Nitzschia sp.

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Nitzschia sp. I
05:10
Captured from Atlantic Ocean 4/4/07 sample. Several specimen are followed. Recorded at 100x magnification on Microscope, with additional magnification of 4-∞ using digital camera.

Nitzschia sp. II
03:36
Nitschia sp. filmed from sample taken from Atlantic Ocean on April 4, 2007, interacting with some other microorganisms; thalassion sp. and pleurosigma sp.

Images at Phytoplankton Sample, 4/07/2007

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Koi - show fish

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Images enlarge to full resolution.
Koi, Japanese Carp, show fish (youtube upload). These were taken at the Brunswick Community College Aquaculture center, and are currently being kept in a recirculating system.

The fish are large. Though related to Goldfish, they grow up to over a ft in length. These particular fish measure over ft in length.


One student remarked today, though large enough for food-fish, Koi are more valuable alive (for show fish).


John Baka, an instructor at BCC said a couple of these large koi are carrying eggs and that's the reason for the branches floating in the pool, for the fish to lay their eggs. I presume the eggs will be attached to the branches and can be gathered for culture.

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Yellow Perch

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Yellow Perch Production
Modified in parts from class notes by Dr. Doug Holland, Aquaculture Program, Brunswick Community College

Yellow perch (Perca flavescens) is a relatively new species to aquaculture. This species is widely distributed, ranging from Nova Scotia to South Carolina along the Atlantic seaboard and throughout the Great Lakes region and as far west as the Dakotas and Nebraska. Commercially, it has been cultured in the upper Midwest, and in the Eastern US from Pennsylvania to South Carolina.

The best culture method for yellow perch is widely debated. The material presented here is based on the extensive experiences of staff at Brunswick Community College and yellow perch farmers in Brunswick County, North Carolina.

Broodstock Management and Egg Collection
Eggs may be collected from the wild, but as with all cultured aquatic species, preferred stock comes from domesticated broodstock. In North Carolina, one of the best places to collect wild eggs is from the Perquimmans River, a tributary of Albemarle Sound. The NC Division of Marine Fisheries manages the waters below the old bridge in downtown Hertford, and there is a healthy commercial fyke-net fishery for yellow perch in these waters. The perch are trapped in the nets during their annual spawning runs in February and March, and fertilized egg ribbons may be easily collected from the nets where the fish spawn. Egg ribbons may also be collected in submerged vegetation along the edges of the river.

Domesticated yellow perch broodfish may be held in ponds at densities up to about 500 lbs/acre. The fish should range from ¼ lb to 1 lb+ in size, and there should be a 50/50 mix of males and females. Good egg production generally requires an annual increase in body weight of at least 50%. Broodfish that are feed-trained will grow and reproduce well on pelleted feeds containing about 40% crude protein and 10% crude fat. Yellow perch generally prefer live food and use of a forage species such as fathead minnows in brood ponds, which will likely improve egg production and success with spawning.

Spawning
Spawning in ponds begins in mid-February. It is a good idea to encourage growth of submerged aquatic vegetation around the edges of brood ponds for the perch to use as a spawning substrate. If there no submerged vegetation exists around the edges, discarded Christmas trees work for spawning substrate. A wetsuit and snorkeling mask may be necessary to recover egg masses in deeper water. Perch often spawn wherever bottom vegetation occurs, across the bottom of shallow ponds. In ponds where the entire bottom is covered with rooted submerged vegetation, only a small percentage of the egg ribbons may be recovered. Egg ribbons should be placed in a cooler full of well-oxygenated water and transported to the hatchery within thirty minutes. Eggs consume oxygen, therefore if the oxygen is depleted the eggs will die.

Fry Production
We have found that standard catfish egg baskets suspended in ordinary aluminum catfish hatching troughs work very well for yellow perch egg incubation and hatching. Instead of rotating paddles we simply place large air stones in the troughs to provide water agitation and aeration. Water from a small header pond is circulated through the troughs at about 1gpm per 100 gallons of trough capacity. During periods of very cold weather, the flow of pond water should be slowed down, and well water (66ºF in Brunswick County) may be added along with pond water or large aquarium heaters may be used to increase the temperature in the troughs. Be very careful using well water in yellow perch hatching troughs. Well water often contains hydrogen sulfide and other toxic compounds. The amount of hydrogen sulfide required to kill yellow perch eggs is barely detectable, and may not be noticeable to anybody but those with the most sensitive noses.

At water temperatures in mid-60'sºF, yellow perch eggs usually hatch in 5-7 days. Hatching time may be up to two or three weeks at colder temperatures. After the fry hatch out, they may be concentrated using light. A 100-watt incandescent "heat lamp" outfitted with a clamp and an 8" diameter reflector, works well and is available at most hardware and builder's supply stores. The light can be clamped to the side of the hatching trough. If all doors and windows in the hatchery are covered and the lights are turned off, the fry will collect under the light in a couple of hours. They are then siphoned into a five-gallon bucket and stocked into fingerling production tanks or prepared nursery ponds.

Fingerling Production in Tanks
Yellow perch fingerlings may be produced in tanks supplied with pond water containing adequate densities of wild zooplankton (a mixture of rotifers and small microcrustaceans is best). 7 days post-hatch, fry should be offered Fry Feed Kyowa B (<250 microns). This feed is available in the US through BioKyowa in Cape Girardeau, Missouri. A 500-gram packet costs about $45, but very little is required to get the fry started on an artificial diet. Once fry are feed-trained, they should be slowly changed over to a finely ground (500 microns or less) freeze-dried krill. After 3-4 weeks, slowly substitute a good quality #0 soft-moist crumble feed, with at least 45% crude protein and 20% crude fat. Rangen Feeds makes an excellent soft-moist crumble feed. After another 3-4 weeks, dry crumbles containing at least 45% crude protein and 12-16% crude fat may be substituted for the soft-moist crumbles.

Yellow perch fry held in troughs or tanks may experience problems with swim-bladder inflation, and settle on the bottom of the tank where they eventually smother and die.

Perch suffering from swim bladder inflation failure (sinkers) are reported from wild populations of Lakes Constance, Geneva, Lucerne, Sempach, and Zurich in central Europe. Sinkers were found at all 7 locations considered in a survey. Relative abundance of sinkers varied from 0.1% to 7.9% of local perch populations. Sinkers from wild populations and sinkers reared in the laboratory showed similar behaviour and malformations. Information on sinker syndrome in 26 physoclistous species is compiled. It is found to be a widespread problem in aquaculture, but is reported here for the first time from natural populations.
Springerlink, Zoologisches Museum, Universität Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland

This is often caused by an ultra-thin layer of lipid (fatty material) that forms on the surface of the water in hatching troughs as the eggs hatch out (the hatching eggs are the source of the lipids). This can be avoided by adding a tiny drop of dishwashing liquid to the surface of the water when the eggs are about to hatch. This may be repeated as necessary. The soap breaks up the surface tension of the water and allows the fry to get the "gulp of air" needed to inflate their swim bladder. Don't overdo it with the soap. It only takes a tiny drop to do the job. More than this will harm the fish.

Fingerling Production in Ponds
Most yellow perch fingerlings are produced in prepared nursery ponds. Small ponds up to three acres in size and 3-5 feet deep work best. The ponds should be drained and thoroughly dried during autumn. Spread about 300 lbs/acre of cottonseed meal over the pond bottom prior to flooding. Begin flooding the ponds 3-4 weeks before anticipated egg hatching. It takes much longer for an adequate zooplankton bloom to develop in winter than in spring or summer, when only a few days may be required to obtain adequate densities of rotifers and early instar microcrustaceans (the preferred food of newly hatched yellow perch). Begin examining the water for zooplankters after 10-14 days. If very few organisms are observed at this time, try inoculating the pond with water from another pond that contains high densities of zooplankters.

Fingerling production ponds should also be fertilized with liquid ammonium polyphosphate (10-34-0 fertilizer grade) or phosphoric acid (0-54-0 fertilizer grade) to promote the development of a phytoplankton bloom. Inorganic fertilizers generally don't work very well to promote phytoplankton blooms at the low water temperatures experienced in January. Begin adding the liquid fertilizer around mid-February at a rate of 1 gallon/acre of ammonium polyphosphate in soft-water ponds, or up to 3 gallons/acre of phosphoric acid in hard-water ponds. Don't use ammonium polyphosphate at the high rates required for hard water in yellow perch fingerling ponds. Yellow perch are very sensitive to ammonia and higher rates may be very detrimental to the fry. Repeat fertilizer application each week until a bloom appears on the pond. Fertilize as needed to maintain a Secchi disk depth of 12-18".

Stock the prepared nursery ponds with 200,000 to 500,000 fry. Lower stocking densities will result in larger fingerlings at harvest. Higher stocking densities may result in greater numbers of fingerlings, but they will be smaller at harvest. Yellow perch fingerlings may be harvested from ponds after 50-70 days. The fingerlings may be trapped with up to 40-50% success, but the remaining fish must be seined or concentrated by draining the pond into pre-constructed catch basins or kettles around the pond drains. Be very careful handling the fish and plan to harvest on cool days.

Yellow perch fingerlings produced in ponds must be feed-trained. Harvested fingerlings should be placed in raceways or tanks with flowing water and good aeration at a rate of 35-40 lbs per 1000 gallons of water. Following stocking of the fingerlings, the water in the tanks or raceways should be stopped and treated with oxytetracycline at a rate of 100g active ingredient per 1000 gallons of water to prevent fin rot. This bacterial disease will kill 30-40% or more of the fingerlings if this is not done.
Begin offering the perch finely ground freeze-dried krill at a rate of 5% of body weight per day. Once the perch are actively feeding, slowly switch the diet over to a #0 soft-moist crumble containing 45% crude protein and 20% crude fat. After about two weeks, dry crumbles should be substituted for the soft-moist feed. Yellow perch are not completely feed-trained until they have been taking artificial feed for 3-4 weeks. By this time, fish that are not feed- trained will starve to death and may be cannibalized by the other fish.

At this stage of their lives, yellow perch will consume up to 15% of their body weight each day. If they are not fed to satiation, they will cannibalize their siblings, and large losses (as much as 50-75%) have been attributed to this.

Frequent grading may also reduce cannibalism. Be careful not to grade the fish too frequently. Excessive handling may stress the fish and cause an outbreak of fin rot or other bacterial diseases. Yellow perch should not be handled at all at temperatures above 26ºC.

Fin rot
Fin rot in perch is generally related to stressful handling and/or severe water quality stress during harvesting. With mild cases can be treatment in a salt bath of 5 ppt will assist the fish in fighting the infection. Severe cases should be quarantined where possible and a veterinarian called to prescribe registered chemicals.
The tolerance for perch with fin rot for live or whole fresh chilled is:
• Minor cases: 5%
Major cases: nil - Fish should be processed for the fillet market.
From Size Gradings, on Fin Rot

Grow-Out to Market Size
There are many opinions among both producers and researchers about how best to produce market-size yellow perch. The market size for yellow perch is quite small compared with other cultured species, ranging from about ¼ pound (115 grams) up to about 1/3 pound (150 grams). Canadian markets will take some yellow perch that are both larger and smaller than this, but 115-150 grams is the preferred range in most markets. At Brunswick Community College and at yellow perch farms in Brunswick County, we have attempted to grow yellow perch to market size in a variety of ways. We have grown perch in open ponds, and in cages placed in ponds. We have successfully produced market-size perch in indoor recirculating systems, and in "outdoor recirculating systems", which utilize tanks supplied with water that is recirculated through ponds which function in particulate removal and biofiltration.

Pond Culture: This has proven to be a rather unreliable way to grow yellow perch to market size. We have tried many different stocking regimes, and have generally found that perch feed poorly, grow slowly (and with great variability in growth rates), and cannibalize each other heavily in open pond culture. When 1-2" feed-trained fingerlings are stocked into ponds, it generally takes 18-24 months to produce market-size fish, and a large number of the harvested fish will be outside the optimum range of size for foodfish markets. There is also low survival (40-60%) due mainly, we believe, to cannibalism. It also appears that pond-reared fish generally have a lower dressing percentage (41-45%) compared with tank-reared fish (45-51%). Total production in ponds ranges from 500 to 2500 lbs/acre per production cycle. This translates to an average production of 700-1000 lbs/acre per year, which is probably not a profitable production rate under most circumstances.

Cage Culture: Yellow perch feed and grow well in cages, as long as water quality is maintained at high levels. Yellow perch are very sensitive to ammonia. When cages are placed in shallow water, fecal material and uneaten feed tend to build up beneath the cage and cause localized problems with high ammonia concentrations in the waters around the cages. For this reason, cages should be placed in deep water (at least twice the depth of the cage) or the cages should be designed so that they can be easily moved. Aeration should be available at all times to maintain water quality around the cages. Large fingerlings (at least 4") must be stocked into cages. Smaller fingerlings necessitate the use of small mesh sizes for cage materials. Small mesh cages do not provide adequate water circulation, and may become completely clogged with algae and debris.

Indoor Recirculating Systems: This has become the most popular method for producing market-size yellow perch. Most market-size perch are produced in the upper Mid-Atlantic and upper Midwest states, where winter temperatures are cold enough to dramatically slow growth rates. Perch are maintained on feed and actively grow year-round in indoor climate-controlled recirculating production systems. They are routinely stocked in these systems at densities up to four fish per gallon, with production of up to 0.5 lb per gallon of tank capacity. Perch may be stocked in these systems at any size, but many producers prefer large stockers, in the range of 3-5". These fish are very expensive, on the order of $0.20 to $0.35 per fingerling (at an average cost of $0.07 per inch for feed-trained fingerlings). There is no reason perch cannot be stocked at smaller sizes, around 1-2", which would cost about $0.07-0.14 per fish. Since it takes 3-4 fish to weigh one pound at harvest, this would provide considerable savings to the producer. Also, yellow perch are prone to significant variability in growth rates, with resultant cannibalism. Cannibalism rates of up to 50% are not uncommon when fish are underfed and un-graded. Feeding to satiation and frequent grading, especially at smaller sizes, will greatly reduce problems with cannibalism. Be careful not to handle fish so frequently that they become stressed, especially at temperatures above 26ºC.

Outdoor Recirculating Systems: The use of outdoor tanks with water supplied by gravity flow from an adjacent pond has been shown to be a very cost-effective method for producing yellow perch in southeastern North Carolina. The water is returned to the pond by a low-head sewage pump. The pond also serves as a particulate settling chamber and biofilter. One example of the various systems now in place in Brunswick County is one that is able to produce at least 5000 lbs of market-size yellow perch in three 5000-gallon tanks supplied with water from a 1-acre pond. By separating solid fecal matter and uneaten feed into a separate small retention pond, we believe this system may be able to produce perch at much higher levels on a per-acre basis. Such a system is currently being planned for construction at Brunswick Community College.



The smaller sizes should be fed as often as is practical, up to three or four times each day. Fish more than 4 or 5 inches only need to be fed once or twice each day.

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Rainbow Trout Culture II

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Rainbow Trout Culture II
Notes modified from Dr. Doug Holland, Aquaculture, Brunswick Community College.

Feeds and Feeding
Many companies manufacture high quality trout feeds. Feeds in all particle sizes are available, beginning with crumbles #00, 0, 1, 2, 3, 4 which are best suited for fry and small fingerlings. Advanced fingerlings, larger fish and broodstock should be fed floating or sinking pellets 1/16", 1/8", 3/16", etc.

Homemade diets should be avoided, especially unsterilized trash fish. The risk of disease combined with a diet that is usually nutritionally unbalanced, may result in a variety of nutritional disorders.

Feed utilization by the fish is of utmost importance.
Feed should be distributed in a manner that all fish get something to eat. To do so reduces variations in growth rate genetically inherent in fish. Such genetic predisposition are made worse by uneven distribution of feed and aggressive feeding instinct among individual fish.

Feeding can be made less efficient and/or wasted because:
1. Low temperatures
2. Excessive flow-through rates
3. Excessive water turbidity (trout feed by sight)

Automatic feeders may reduce labor costs, but also may result in poor feed conversion and/or uneven feed distribution, which contributes to higher feed cost. The cost of feed is generally higher than labor costs, therefore automatic feeders may represent a "false economy".

The best way to keep track of feed conversion is to keep accurate records of daily consumption rates and frequent sampling of fish for average size and weight. Fish sampling should be done preferably every two weeks but at least once per month.

Grow-Out Techniques
"The least-cost producer wins"
To develop a production strategy with any culture, available markets should be investigated first, then "working backwards" to determine a workable production strategy. By knowing the particular requirements of any market, the producer can develop methods to produce at the lowest unit cost.

Most consumers want an even supply of food-size fish throughout the year. Fluctuations in demand occur during certain times throughout the year:
- Thanksgiving and Christmas. Less people eat fish and seafood during the Holiday season.
- During Lent many people give up meat for religious reasons. Lent begins on Ash Wednesday the day following "Mardi Gras" and ends at Easter. The demand for fish and seafood increase during this time of year.

Fertilized eggs/embryos of trout, called "eyed trout eggs" are available from various parts of the world during most of the year.

For grow-out to market size fish, differential growth rates in fingerlings make stocking almost any size during most of the year possible. Differential growth rates during grow-out to market size further contributes to overall size variability, making market-size fish available throughout the year.

Growth rates of fish may be controlled by any combination of:
1. Genes. Natural variability exists between different strains and individuals within strains.
2. Feeding rates
3. Temperature which is not under the control of the farmer, but may be anticipated and utilized in overall production strategy.
4. Current/flow rate - swimming against rapid currents requires more energy which reduces growth rate at a constant feeding rate.
5. Grading. While it is best to have every fish growing at an optimum rate, naturally the rate will differ from individual to individual and from strain to strain. This can be used to ensure that market size fish are available at any and all times of the year.

Grading the fish
Grading should be done on a regular basis, but if done too frequently it risks increased stress and reduction in production levels.
A variety of grading methods are available. Producers should choose carefully to ensure the greatest grading efficiency with the least stress on the fish as possible.

Effluent Management
Types and amounts of allowable effluents from trout farms are governed by state and federal regulations. The most important of these is the NPDES permit, National Pollutant Discharge Elimination System. An NPDES permit is required of trout farms that produce more than 30,000 lbs annually.

Trout streams and other coldwater receiving waters are likely to be more profoundly affected by effluents than warmer waters, due to the low natural nutrient levels of most coldwater streams.

Suspended solids are the most serious effluent problem:
1. Contribute to Biochemical Oxygen Demand (BOD).
2. Can completely cover the bottom of receiving streams.

Settleable Solids = Suspended solids that settle out of standing water in one hour.

0.3 lb. of settleable solids are produced for every lb of feed offered to the fish in trout raceways.

Settleable solids are typically removed from effluents through the use of sedimentation basins.

Total pollutants in trout farm effluents come from many sources, but most originate from feed offered to the fish.

Levels of effluent pollutants due to feed can be calculated using the equation:

Average ppm pollutant = Pollutant Factor x Lbs Feed
Water Flow (gpm)

Pollutant factors for this equation:

Total ammonia 2.67
Nitrate 7.25
Phosphate 0.417
Settleable solids 25.0
BOD 28.3

Example
250 lbs of feed are offered each day in a hatchery with 1,000 gpm of water flow. What is the concentration in ppm of settleable solids in the effluent?

25.0 x 250
------------- = 6.25 ppm
1,000


An example of a sedimentation basin design from arizona.edu on Filtration and Biofiltration
Sedimentation basin design: Wide inlet (to reduce velocity), a surface area of .7 to 1.4 sq. ft. of basin per gpm flow (for feces with a specific gravity of 1.01 or greater), wide outlet weir (never a stand pipe), no baffles (which increase velocities) and a simple waste drain. A depth of just a few inches is enough for most designs.
Source: University of Arizona
Sedimentation Basins
These are usually tanks, ponds, lagoons, etc. which serve the purpose of slowing velocity of the water, and allow suspended solids to settle to the bottom.

Four factors taken into account for design of sedimentation basins:
1. Retention time
2. Density of waste solids
3. Water velocity and flow distribution
4. Water depth

Retention time = average period that a unit of water remains in the basin.

Retention time ranges from 15 minutes to 2 hours. For a given rate of flow, retention time increases with area and depth of the basin.

If not carefully engineered, a sedimentation basin will have an area of rapid flow down the middle, with backwater "dead zones" where water stagnates and is replaced very slowly. A system of baffles should be incorporated into the design to ensure even flow through the basin.

The basin should be about 1.5 feet deep. A shallower basin promotes scouring of the bottom, keeping solids suspended throughout the basin. There may not be enough time for solids to settle out completely in a deeper basin.

There are several types of sedimentation basins:

1. Linear clarifier - a modified concrete raceway.

Water should enter the raceway through a series of screens to distribute flow and reduce turbulence.

2. Lagoons - usually a shallow earthen pond.

The larger the pond, the more effluent it can accommodate.

3. Commercial Settling Systems

There are many types and designs of these systems available. They all generally incorporate baffles and settling tubes. This type requires less space and retention time than linear clarifiers or lagoons. They are expensive, and usually impractical in commercial aquaculture.

Solid Waste Disposal
Over half of all nutrients released by trout farms are in the form of settleable solids. The sludge from sedimentation basins is a high quality organic fertilizer. It may be composted and made available to organic farmers, gardeners, etc. It may be possible to market such material to help offset costs of waste management.

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Rainbow Trout Culture

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Feed and fingerlings make up greater than 70% of the total cost of raising trout. Assuming a sales price of $1.10 per pound, and total cost of production of $0.76, the farm nets $21,452 per year on 60,480 pounds harvested.
-NC Dept. Agriculture and Consumer Services

Modified from notes by Dr. Doug Holland, Aquaculture, Brunswick Community College on Rainbow Trout Culture I

North Carolina is the second largest producer of rainbow trout in the United States, following Idaho in production.

Aquaculture is the fastest growing segment of U.S. agriculture. The farm valueof the U.S. aquaculture industry is estimated at nearly $1 billion. Trout food fish production accounts for about 10% of the total value, and catfish for about 50% of the value. Trout farming is the oldest form of commercial fish production in the U.S.; trout have been grown in culture systems for over 150 years. Rainbow trout is the predominant species raised. Trout are cultured in earthen or concrete raceways (rectangular tanks) supplied with flowing water. In 2000, an estimated 447 trout operations harvested and sold 59 million pounds of trout valued at $64 million. Idaho produces 58% of the total dollar production. North Carolina is the second largest producer, with about 7% of the production value. In 2000, U.S. trout farmers sold 70% of their harvest to processors, 18% through recreational fee fishing operations, 5% directly to restaurants and retailers, and the remainder to other outlets. Production in the U.S. trout industry has remained stable over the last decade. Three reasons for limited expansion are: lack of suitable sites for new facilities; increasing costs associated with fish waste management; and difficulty in competingwith the retail prices of imported trout orother seafood products.
(see http://www.ncagr.com/Aquacult/Trout01.pdf)

There are about 89 farms in NC, and most of these are west of Asheville in southwestern North Carolina. The largest concentration is in Transylvania, Graham, Macon and adjacent counties.

The annual production of rainbow trout in NC varies, but lately has averaged around 7.1 million lbs, worth 1.10 per lb on average. It is obvious when looking at these figures that most of the farms in NC are small-scale family operations, each producing less than 100,000 lbs of trout each year. There are several large farms, however, and some of these are quite profitable.

Environmental Requirements
Rainbow trout is a coldwater species and requires water temps less than 68°F year-round for optimum growth. They may survive at somewhat higher temps, but with little or no growth and high stress levels.

Culture of rainbow trout in raceways requires large amounts of flow-through water. A farm with a holding capacity of 100,000 lbs of fish would require a minimum flow of 5000 gpm (gallons per minute) during the driest part of the year, assuming that it has oxygen-injection technology and a highly experienced manager. Few places have this much high-quality, cold water available year-round, even in the NC mountains. Most of the best sites in southwestern NC are already taken.

Tank and Pond Design

Major types of culture structures:
1. Ponds
2. Raceways
3. Tanks

Earthen ponds are still utilized on older farms, but are less than optimum for grow-out of food fish, though useful for fee-fishing operations. The irregular flow in current create "dead areas" which inhibit circulation of water. Difficulties in grading and sorting fish are created by slope in the side of ponds. Higher maintenance than raceways or tanks is required due to accumulation of organic matter and weed problems, etc., which are relatively economical to build, though to conserve on unit/volume, often constructed larger than they should be.

The larger the pond, the more difficult to manage. Using small, straight-sided earthen "raceways" has proven a better method and make for easier management than small round ponds. They can be lined with butyl liners to make management even easier.

"Unless your ground is a thick impervious clay, it is important to line your pond with a waterproof layer. There are several types of material on the market which you could try but most experts agree that the final choice is between relaxing beside a deluxe, butyl rubber lined pond or continuously repairing the holes in a pond lined with one of the cheaper alternatives. To protect the liner from stones you can use a layer of old carpet or sand under the butyl sheet.

If a layer of geotextile under the butyl helps protect it against stones, then another layer of geotextile, this time on top of the butyl, helps the soil to adhere to the sloping edges."
From Building a Pond - Butyl Liners

Raceways are the most widely established culture system for Rainbow Trout in both the United States and Europe. Comparing advantages with disadvantages, the disadvantages are generally outweighed.

The advantages are large densities of fish can be maintained, with few "dead" areas. Compared to ponds, differentiation in growth rate is reduced. Crowding fish for grading and harvest is much easier. A raceway can have a built in system for crowders and bar graders that are easily moved up and down the raceways, without physically removing them from the water or transferring them. Raceways may be partitioned, where several size classes of graded fish may be held simultaneously.

The disadvantages are a lack of utilization of the full water volume and abrasion. Fish tend to "school" together in 1/3 to 1/2 total volume of the raceway. Raceways are usually either poured concrete or concrete block construction. When fish are crowded to feed or grading/harvest, repeated contact with concrete walls may open them up to bacterial and fungal infections.

Round or semi-round tanks are being used by many newer farms. An advantage of round tanks is the self-cleaning aspect which takes place due to centripetal forces by the circulating water. Uneaten feed and fecal wastes are moved to the center of the tank as water moves around in circular motion. Once collected these materials are removed using a "double-drain" type system. This system reduces need for maintenance and labor costs.

Almost any tank can be used, though important it is durable, weatherproof and UV-resistant for outdoor use. It should be round or semi-round (above). This is also important in establishing a current against which the fish will swim, as is the habit of Rainbow Trout. It is important as well to obtain a tank that is already assembled or be easily assembled, and economical in cost. Tanks which are more convenient to set up and use may create an added expense, compared to cheaper tanks which will be durable though requiring more time and labor. The costs of labor and management must be compared with the cost of tanks.

Round tanks are preferred by many trout producers because the entire life cycle of the trout may be carried out in a variety of tank sizes, from broodstock to growout. There are some systems which now provide tanks that allow for fertilized eggs to be placed on top, and fry to pass through to an underlying container when hatched, which may then be removed, allowing fry to grow to fingerlings or even to market size. A major disadvantage of tank systems is the high cost, a higher initial investment is required compared to raceway systems, and comparatively, raceway systems are much more expensive to build and maintain than ponds.

Strains of Rainbow Trout
Once the culturing system has been constructed, the strain of trout must be determined.
Different strains have different characteristics that affect production and marketing:
1. DO tolerance
2. Temperature range/tolerance
3. Optimum culture densities
4. pH range/tolerance
5. Water hardness requirement
6. Growth rates under various temperature regimes.

Choosing a strain best suited to individual environmental conditions for each farm is important.

Optimum Production Level
Optimum production level for a particular system/farm may be determined by the equation:

OP = T + F + O + C

Where:

OP = optimum production level

T = ideal temperature for optimum feed conversion

F = correct amount and size of food

O = dissolved oxygen level needed to metabolize food

C = ideal flow rate for optimum exercise (swimming against the current).

Increase in temperature within the optimum range for trout production will result in increased metabolic rate, therefore feeding rate. Feeding rates should be adjusted with changes in temperature. These increases due to an increase in temperature are accompanied by an increased demand for oxygen. DO (dissolved oxygen) saturation level decreases with any increase in temperature. Due to these factors, supplemental sources of oxygen to keep DO at optimum levels, at or near saturation, are required. Aeration devices or oxygen injection may accomplish this. Oxygen injection, using pure bottled oxygen is expensive, but in many cases is economically feasible, even desirable.
Producers must be on guard not to become dependant on a pure oxygen injection system because it creates an artificially high level of production, which is unsustainable over long periods of time. Besides a risk of mechanical failure, it also creates stress to the fish due to crowding which may reduce feeding, growth rates and even potential risk of disease. An outbreak would spread rapidly and cause high mortality rate. Producers must compare risks with profit when dealing in such highly intensive production. While an oxygen injection system may look good theoretically, losing all your fish at once due to a system failure could put you out of business.

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Hybrid Striped Bass

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From Dr. Doug Holland's notes (Brunswick Community College) on Hybrid Striped Bass, with some modifications for this blog.

Top to bottom: white bass, striped bass and hybrid striped bass (Bodie bass)
Source: NC Wildlife

Various hybrids of the striped bass have shown improvement in survival, improved growth, greater resistance to disease, and tend to be hardier under culture conditions than wild striped bass.

-The two most common crosses are:

"original cross" - striped bass (Morone saxatilis) female X white bass (Morone chrysops) male
-R.E. Stevens, SC, 1965, (Also known as the "Palmetto Bass".)

"reciprocal cross" - white bass female x striped bass male.
-Bayless, SC, 1966 (Also known as the "Sunshine Bass".)

The "original cross" remains the most popular and numerous in commercial culture. Newly hatched fry are larger and have higher survival rates in pond fingerling production than do the "reciprocal cross," therefore fingerling production is more profitable.

Hybrid striped bass are produced in all types of systems, including:

1. Open static pond culture (NC)
2. Cage culture (very limited)
3. Raceway & tank culture using flow-through water (FL, CA, MS, etc.)
4. Intensive recirculating systems (mixed results)

Hybrid fingerlings are traditionally produced in fresh water. But growout to food size is done in both fresh and brackish water, and is also possible in saltwater. Striped bass are anadromous. They spawn in freshwater and move into saltwater as adults.

"Striped bass (Morone saxitilis) are one of 7 anadromous species found in the Cape Fear River system. Due to dramatic drops in the population, a coast wide moratorium on striped bass fishing was imposed from 1985 to 1990. Although striped bass populations in other N. C. drainages have rebounded, the Cape Fear River striped bass population has not (Mallin et. al. 1998,1999,2000). Although declines in water quality and the introduction and possible predation and competition by nonnative catfishes are probably contributing to the problem, one specific culprit could be competition from hybrid striped bass. [...] Hybrid striped bass are a hybrid of striped bass (Morone saxatalis) and white bass (Morone chrysops). They have been stocked as a put and take fishery in Lake Jordon nearly every year since 1983. The hybrids are introduced to the Cape Fear River by flooding events. Through competition, hybrids utilize the resources normally available to striped bass (Patrick and Moser 2001). Hybrids do not reproduce and so the resources they keep from striped bass are not converted into reproduction. As a result of competition with hybrids, striped bass may not be as healthy and in turn, not produce as many juveniles. Tag and recapture data from studies conducted in this drainage suggested that hybrids conduct a spawning run with true striped bass as has been documented in other systems (Patrick and Moser 2001, Bishop 1967). Due to competition with true striped bass for food resources and spawning habitat, hybrid striped bass are likely having a negative impact on the striped bass population in the Cape Fear River system. Catch-per-unit-effort data showed a statistically significant drop in the fall gill net samples (Figure 32). While commercial landings of striped bass in North Carolina have shown a gradual increase since 1990. Landings in the Cape Fear System remain low and this is the only river in North Carolina that stocks hybrid striped bass. Although the hybrid striped bass population appears to be decreasing, future surveys should examine whether this trend continues."
From Anadromous Species of the Cape Fear River System, UNC, Wilmington

Phases of Hybrid Striped Bass Production:

1. Phase I fingerling production
-Generally to about 2" (1-2.5")

2. Phase II fingerling production
-Range from 3 to 10 inches (average 4-6")

3. Phase III or Foodfish Production
-Range from 0.7 to 4 lbs (most desirable market size is 1.5 to 2 lbs).

The production of phase I and phase II hybrid bass is covered in Hatchery Management I and II.

Production of Market-Size or Phase III Fish

Pond Culture
Since the late 1970's, production of large striped bass has been in practice at the Edenton National Fish Hatchery, where they have used pond culture to produce, maintain and spawn domesticated striped bass broodstock from five different Atlantic strains.

During the early 1980s attempts to produce stripers and hybrids in earthen ponds by some commercial farms in California, Maryland, and elsewhere was met with some success. In the late 1980s Carolina Fisheries was established in Aurora, NC to commercially produce market-size Hybrid Striped Bass in earthen ponds and was the first financially successful pond-based farm. It has been followed by many others in eastern North Carolina. In all twenty eight farms were established by 1998, thirty five by 2000.

In all, the largest pond-based farm is located in northern Mississippi, covering 600 acres (larger than all others combined).

"It may be the only farm-raised hybrid striped bass farm in Mississippi, but it is the largest such operation in the world."
From Nature’s Catch is largest striped bass farm in the world

Current Pond-culture Techniques
Earthen ponds should average about three acres in size, but can range between 1-5 acres and 4-8 ft. in depth. Production can be in fresh water, but minimum hardness and alkalinity values of water should be 100 ppm.

Weed control is an important contributing factor in good production, though management may be difficult in clear, hardwater ponds. Ponds should be filled during winter and fertilized in at the beginning of late winter and continued into early spring at high rates with liquid 10-34-0 or phosphoric acid to promote phytoplankton bloom to adequately shade the bottom.

Phase II fingerlings may be stocked after filling the pond. Generally they are more readily available in spring than any other time of the year. When temperatures are moderate, handling the fingerlings cause the fish less stress.

Ask for health certification by a qualified veterinary lab to make certain the fish are healthy, well graded, and sufficiently large enough to produce adequately sized marketable fish in one growing season. Though this may vary according to geography. Use the same method for estimating average size and numbers of fingerlings as outlined for catfish. In eastern North Carolina, a one hundred gram fish will grow to about 1.5 lbs in one growing season.

Stocking rates can range between two and five thousand fingerlings per acre. Optimum results have been obtained by stocking between 3000-3500 per acre.

Acclimating Fish to Water
As with any species of fish, fingerlings should be acclimated to water temperature before stocking them into the pond. This involves pumping water from the receiving pond into the haul tank over a period of 20-30 minutes until temperature and pH are approximately equal. A difference in temperature which comes to more than 10°F, is considered large and a longer acclimation period is required. Three minutes for every degree up and 1.5 minute for every degree down.

Hybrid Striped Bass are normally fed a diet consisting of 38% protein and 8% fat, but better results have been achieved using a feed containing 40% protein and 10% fat. A feed that is a mixture of both floating and sinking pellets is best. Hybrid Striped Bass sometimes feed slower after satiation, and all-floating feed may end up going to waste on the embankment.

Feeding rate should be around 2% of body weight per day, depending on:

1. Age
2. Size
3. Water temperature
4. Time since last feeding
5. Water quality
The best method to determining appropriate feeding rate is by observing feeding activity and adjust accordingly.

Good water quality is crucial in production. Bass are less tolerant of poor water quality. Pay careful attention to DO (Dissolved Oxygen levels) which should never fall below 4ppm. The dissolved oxygen level should consistently be kept above 5ppm. Aeration capacity is required for production. A three acre pond should be outfitted with a 5 horsepower electric paddlewheel aerator. Variable horsepower aerators should be outfitted on larger or smaller ponds. Sometimes additional aeration is required, and is usually supplied with PTO-driven paddlewheels. Most farmers have one tractor with PTO paddlewheel for every four ponds on the farm.

Keep ponds salted to increase chloride levels up and prevent problems with nitrite.

To keep ammonia levels down and ponds cool during hot summer weather it may become necessary to frequently flush ponds. Hybrid Striped Bass is really more of a coolwater than a warmwater species.

Disease and Parasites
Yellow grub (Clinostomum complanatum), a digenetic trematode is the most economically devastating disease & parasite problem encountered. These parasites are characterized by their life cycle... having a definitive host (birds) a first intermediate host (snails) and a second intermediate host (fish).


Rams Horn Snail - An intermediate host in the life cycle of the Yellow Grub.
Photo by author, 2007
No effective FDA-approved treatment exists for yellow grub, though it may be controlled by eliminating the predatory birds (primarily cormorants and great blue herons) and/or the snails.
• Trained dogs can chase away birds or a depredation permit can be obtained to shoot them. By controlling weeds snails can be effectively reduced, particularly bottom-rooted macrophytes on which they feed. Introducing snail-eating fish is now one area of research being looked into.
• Snail numbers may be greatly reduced by draining and drying ponds annually. Quicklime (CaO) may be applied to remaining puddles or copper sulfate at 10 ppm to kill any remaining snails. Be aware both treatments will also kill any fish remaining in the puddles.

ICHTHYOPHTHIRIUS MULTIFILIIS, or "ICH" for short, is one of the freshwater fish diseases. Ich is a waterborne microscopic parasite that reproduces in small colonies among the slime coat and/or skin of your fish. A common sign of beginning stages of Ich infection are what is called "flashing", where fish will swipe against aquarium decorations or the gravel at the bottom of the tank in an attempt to seemingly scratch themselves. Only one or two small colonies will appear at first, and be very difficult to identify until this infection advances to near maturity. The irritating Ich parasite, if untreated, will very rapidly overwhelm the fish with tiny white spots, making your fish seem as though they have been sprinkled with salt.
Source: http://www.fishtankguy.com/health.php

Ich (Ichthyophthirius multifiliis) is a protozoan parasite that sometimes causes devastating losses in commercial Hybrid Stripe Bass, and other species. This parasite is difficult to treat. The best prevention method is through the use of disease-free certification of incoming fingerlings and avoid use of water supplies containing wild fish.

Other common diseases include the bacterial diseases MAS (Aeromonas spp.) and columnaris (Flexibacter columnaris). Terramycin medicated feed is used to control these and other bacterial diseases, but is not specifically approved by the FDA for use on hybrid striped bass intended for use as human food.

Other disease problems have been reported but are either secondary (such as fungal diseases) or relatively rare.

Harvesting Hybrid Striped Bass
Hybrid Striped Bass are harvested using standard seining techniques. They are sorted by size and packed in 100 lb boxes on ice for shipment to East Coast markets, primarily Northeastern US and Florida. Some fish are sold live, to live-haulers for shipment to Asian-American markets in the Northeast.

Single-Pass Tank/Raceway Culture
Successful culture of Hybrid Striped Bass in single-pass tanks and raceways are nearly as lucrative as pond culture, depending on circumstances. Fish grown in these systems require the same basics in feed and water quality. Some advantages are the lack of problems with yellow grub, as long as the fingerlings are grub-free. There are better feed conversion than in ponds and harvesting is easier and less costly. Such factors help offset increased costs associated with intensive culture in tanks and raceways.

Recirculating System Culture
Sufficient attempts have been made to grow Hybrid Striped Bass in recirculating systems, but many failed due to problems associated with water quality and disease.

Cage Culture
Cage culture of Hybrid Striped Bass holds promise in locations where water quality is sufficient for good health and growth rates throughout the growing period. Feeding in brackish public waters is likely to cause degradation of water quality around the cages. If large numbers of fish are fed in many cages in a semi-closed brackish water body (such as a small sound or lagoon), a generalized reduction in water quality over the whole area is likely. Even if cage or net-pen culture is demonstrated to be technically and economically feasible, it may not be politically acceptable in many areas, and is likely to be regulated out of existence before it can get started.

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N.C. trout, catfish sales increase

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Shoppers buying N.C. trout, catfish

(Winston-Salem Journal (NC) (KRT) Via Thomson Dialog NewsEdge) Mar. 6--The N.C. Department of Agriculture and Consumer Services said yesterday that the state's sales of farmed trout and catfish rose last year because more people understand the nutritional value of fish.

According to the department, trout sales increased about 10 percent, to $7.2 million last year. Catfish sales increased 19 percent, also to about $7.2 million.

North Carolina ranks second, behind Idaho, in trout sales, the department said. The state ranks sixth in the country in catfish sales.

Read the entire article...

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Stages of Fish Larvae Development

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I've purchased a copy of Zooplankton of the Atlantic and Gulf Coasts (A Guide to Their Identification and Ecology) by William S. Johnson and Dennis M. Allen.

While skimming this book I found many useful and informative sections on groups of zooplankton, including fish. Below is an example of the descriptive illustrations found in this book.

Understanding fish larvae is important in Aquaculture, including knowing the proper timing for changing between food sources, as in transferring fish from hatchery to growout ponds. An example can be found in the sidebar, with a list of catfish life stages.


Typical fish egg




Illustrations from Pg. 270, Zooplankton of the Atlantic and Gulf Coasts
Anatomy of larval fishes, based on naked goby Gobiosoma bosc. Middle illustration shows an early feeding stage that has yet to develop fin rays. The last in the series is a juvenile, which is generally defined as a young individual that is fundamentally the same as the adult in morphology.

Excerpts from Zooplankton of the Atlantic and Gulf Coasts, pg. 269-271
"A few species attach sticky eggs to objects at the bottom, but most are simply released into the water column; some are bouyant and some sink to the bottom (demersal eggs). Fish eggs are usually spherical, from 0.5 to 2 mm. The transparency of most of most fish eggs distinguishes them from the typically opaque eggs of invertebrates. Recently spawned eggs have oil droplets or "yolk" that support early development. Development of an embryo is usually rapid, and often within hours of spawning, the outline of the young larva is easily seen within the egg. At hatching, the now-free larva still has a yolk-sac attached to support early development.
The change from the larval planktonic phase to the juvenile and adult lifestyle often involves "remodeling" of the basic larval body plan, resulting in major changes both in morphology and in functional capabilities. The newly hatched yolk sac larvae grow and develop using nutrients provided in the yolk. As the larvae grow, they add musculature, fin rays, and sensory capabilities. Newly hatched larvae are feeble swimmers, but swimming capablities improve rapidly as larvae grow. Some larvae show schooling behavior at a relatively early age. As swimming speed and endurance increase, some larvae show distinctive patterns of vertical migration that may be associated with predator avoidance, feeding migrations, or selective tidal transport. Early larvae are usually transparent with pigmentation increasing during growth.
When the yolk sac is resorbed, the larvae enter the critical "first feeding" stage where they must find and capture prey in the plankton or perish. First foods are quite small; rotifers, ciliates, and copepod nautilii. Vision develops early, and most larval fishes are visual feeders. Prey are perceived at close range, usually within one fish body length... Prey detection and selection seem to be based on prey size more than on any other factor, but motion and color may come into play. Feeding stops in complete darkness but may continue in moonlight. It is interesting that larvae can see in and feed using ultraviolet light, a capability lost in many adults."

Zooplankton of the Atlantic and Gulf Coasts (A Guide to Their Identification and Ecology) by William S. Johnson and Dennis M. Allen is available at amazon.com

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Aquatic Food Web and Aquaculture

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The past week I've spent a lot of time with my new toy, the microscope and realizing the difficulty of properly identifying phytoplankton/zooplankton, decided to order a few select books which may can help in that arena.
One of those books I chose after an extended surf on amazon is Pennak's Freshwater Invertebrates of the United States. I received the book just yesterday, have skimmed over it and rather pleased with the sheer number of illustrations, though the vast majority are line-drawings and not in color. Nonetheless it appears it will make a valuable reference book on freshwater invertebrates. There's a large section dedicated solely to rotifers or, properly rotifera (Wheel animals) Chapter 7 pgs. 129-190, a subject that's raised often in Aquaculture. It contains a rich collection of illustrations to help identify individual species of rotifers.
From looking it over, it seems this book would be best approached if you read the introduction first instead of skipping to latter chapters. The introduction seems to be plentiful in information that brings the reader up to date on issues related to freshwater invertebrates.

In our class, the instructor gave me a copy of Zooplankton Succession and Larval Fish Culture in Freshwater Ponds, by Gerald M. Ludwig, (a full list of documents in pdf format, are listed here http://srac.tamu.edu/fulllist.cfm). In this paper it tells the proper timing to add fish to the pond. You don't want to put the fish in too early, for lack of plankton (their food source), and too late can result in the zooplankton eating the fry:

Tiny fry eat only tiny prey, but tiny fry are preyed upon by many creatures bigger than they are. It is important to know the size of the fry you are stocking and to make sure that the pond you are putting them into contains plankton of the size that will be their prey and is also void of creatures that will prey on the fry.

Fish fry eat zooplankton, phytoplankton and tiny plants and animals attached to objects on the pond bottom... Most fish fry eat three main types of zooplankton-- rotifers, copepods and cladocerans. For the tiniest fish fry, small rotifers may be the only zooplankton small enough to eat. For larger fry, the smallest rotifers may not provide enough nutrients to make chasing and ingesting them worth the effort. Copepod nauplii, which are just hatched copepods, are important first foods for larval fish, too. Protozoans may also be eaten, but little is known about their contribution to fry diets.
- Zooplankton Succession and Larval Fish Culture

The document goes on to tell the stages of succession in ponds, the first group appearing in ponds are the rotifers which obtained their name from their "wheel organ," a ring of cilia that appears to rotate around the mouth. Rotifers can reach maturity in 2-8 days, and hatch from "resting eggs" that survived on the bottom of the pond while it was dry. Most are asexual, until conditions are harsh, then they become sexual and and resting eggs are produced again.
Rotifers are followed by copepod nauplii, the second largest group to appear in ponds, and reach maturity about 18 days after the pond is filled. With their growth (up to 2-3mm) they provide larger food source for larval fish. Only larger fry such as catfish have large enough mouths to eat adult copepods.

Although copepods may be prey for larger fish fry, sometimes the roles are reversed. Introducing small fish fry into a pond full of large copepods can be disastrous... When cyclopoid copepods are prevalent, they may eat all the fish fry stocked.
- Zooplankton Succession and Larval Fish Culture

The document explains proper timing of fry stocking, such as "the proper timing of fry stocking in relation to filling and fertilizing the ponds, can make the difference between having an abundant harvest or a complete crop loss... and optimum growth of fry."
The entire document can be downloaded at http://srac.tamu.edu/fulllist.cfm).

To understand the aquatic food chain itself, and problems associated with reliable research in this area, is explained in broader detail in Pennak ...

Page 32, Pennak's Freshwater Invertebrates of the United States
"During the past two generations the literature of aquatic biology has been replete with "productivity" and "trophic level" studies. It is unfortunate that most of these studies are misleading because they (1) are seasonal rather than year round, (2) have been conducted on complex (rather than simple) ecosystems, and (3) are based on only a fraction of the species making up a particular ecosystem. As a consequence, the generalizations postulated in many of these investigations are open to doubt and modification. Actually, a much more fruitful approach of population dynamics and interrelationships involves habitats characterized by few species and few niches. Examples are alkali and saline ponds, relatively barren alpine lakes, spring brooks, very small ponds, warm springs and small mountain streams. Using such bodies of water, it should be relatively easy to determine food habits of individual species and to make quantitive estimates of populations. Productivity indexes, food cycles, energy transfers from one trophic level to another, species interactions, and seasonal population fluctuations are all important ecological concepts that should be derived from such studies on a year-round basis. It is important to note that the measurement of associated physical and chemical factors in small streams, lakes, and ponds is simpler than in more complex types of aquatic habitats and in terrestrial habitats.

Fig. 1.12 Basic features of aquatic food webs. See text for explanation.
Nevertheless, even in the simplest aquatic habitats the determination of pyramids of numbers and food chains (or, better, "food webs") is an involved problem, and only a very few thorough and inclusive studies have been attempted. The great majority of trophic investigations are concerned with only a few energy or biomass transpositions, the remainder being only roughly estimated. In any such study the basic role played by detritus [that is, loose fragments or grains worn away from rock and/or disintegrated, eroded matter] and bacterial action should not be minimized. In a schematic fashion, Fig. 1.2 shows the fundamental food interrelationships for any aquatic habitat, regardless of size and complexity. Only recently have aquatic ecologists come to realize the overwhelming role of detritus in the food web. The significance of various segments of this diagram vary enormously from one habitat to another. Some habitats, for example, have few or no fishes; other habitats have no rooted aquatics or a poor substrate fauna.
Solid lines indicate consumption or utilization of food. Broken lines indicate death and disintegration of detritus as the result of cetain bacterial activities. The circle arrows originating and ending at "zooplankton," "fish," and "substrate fauna" are meant to show that certain species in each of these categories are carnivorous and feed on other individuals within the same category. Actually each such category may represent two, three, or more trophic levels. "Substrate fauna" includes all bottom invertebrates as well as protoctistans, micrometazoans, and macrometazoans associated with the surface of rooted aquatic plants and other objects. By inference, "bacteria" also includes molds and their activities.
For simplicity, certain minor aspects of this food web have been ommitted. For example, the contribution of excretory materials to the main reservoir of dissolved nutrients is not shown. By inference, "fish" should include other vertebrates, such as frogs, salamanders, and turtles. Not shown, but nevertheless intimately concerned with the continuing balance within the web, are the nitrogen, sulfur, and phosophorus cycles. These are fundamentally similar to the same cycles operating in terrestrial habitats."
Source: Pennak's Freshwater Invertebrates of the United States, pg. 32-33

yep, Pennak is a great reference for freshwater inverts.. I have a 1978 edition on my shelves -- haven't used it in awhile since I really don't do FW stuff anymore. I just pulled it out and checked out the intro.
You're right -- it's a good discussion on the FW food web.

Enjoy your new treasures!

Terri
www.ncseagrant.org

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Closterium

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I am taking a shot in the dark at what the identification of this particular creature is. The closest thing I've came across that looks anything like it,

Closterium is a desmid, a microscopic green algae that occurs in all types of freshwater habitats. Desmids are typically one-celled, though sometimes filamentous or colonial, and are divided symmetrically into semicells connected at a central point. Closterium is characterized by a sickle shape and sometimes contains gypsum crystals.
Source: Closterium Video No. 1

Source: Closterium Tables, XXVII, XXVIII, XXIX, XXX

More Closterium Images

(+/-) Enlarge Photo
Cloisterium resting near Cypridopsis

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Alonella - Zooplankton

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The Genus Alonella is a group of very small waterfleas. Fine features of the carapace and postabdomen are used to distinguish among species - necessitating use of a high-powered light microscope at a minimum.
Source: Genus Alonella

Large image, 1298 x 1289 pixels, 295 k

I am not certain yet which species this waterflea would be classified among, but I'm positive it's Zooplankton and fairly certain it falls within the genus Alonella.
This photo was created by fine-focusing at two separate depths and merging the photos. Nice seeing its wee little legs (antennae?) in detail.

More Photos and Video of Alonella

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Feeding the Catfish

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Chad at BCC told us he was going to feed the catfish, and if we wanted to see them come up to eat... to follow. I captured some neat shots today, with the catfish surfacing for food pellets.




Image enlargement
Catfish surfacing...

Image enlargement
Catfish surfacing... and food pellets floating nearby in the water.
Catfish video - Windows Media Player
feeding_catfish.wmv
4967 kilobytes / 4.96 meg

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Volvox

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Several years ago (around 2003) I made my mind up that one day, I was going to photograph a volvox after learning about these fascinating little creatures. They're somewhere between the plant and animal kingdom. A volvox is a colony of sisters, but they use photosynthesis / chlorophyll like plants do.

Made a goal, stuck to it, and made it happen.
Today, after all this time, I captured my first volvox. Mind you, it's not much of one, but it is a volvox. And, for all case and purpose, that's what matters. I've tried multiple samples of algae over the weekend, and today I tried a new pond out (out back of the Aquaculture facility) and in the dissection microscope, I saw a volvox. Twice it was lost behind other material, but alas I did capture it on my camera.

Enlarge Image The volvox was located at the lower right hand corner of the photograph. Photograph made at Brunswick Community College by me of course. *smile*

Later this evening, I did capture a clean, green little volvox... all to itself, and made video and photos of it.

Volvox






Additional Links
Volvox, Images and Videos, Pg. 1
Volvox, Photographs, Pg. 2
Volvox, Photographs, Pg. 3
Volvox, Photographs, Pg. 4

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Spring Break

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Since this is my "college journal" of sorts to tell the world my joy, whoa and tribulations... I'm really looking forward to upcoming Spring Break. aaaarrrrggghhh... I really hope I'm going to be able to catch up on all the loose ends with my school-work.

John (instructor at BCC) recently gave me a printout, "Aid to the recognition of Fresh-Water Algae, Invertebrates, and Fishes"... after peering through the microscope for several hours and seeing such diversity of life-forms in different samples of water (three to date),
1. John's "Algae tank",
2. a sample strained from a salt-water tank, and lastly,
3. the BCC Aquaculture Ctr. has a tiny pond with lily pads growing in it. I began seeing the significance of the paper he gave me.




Lilypads in a tiny pond in front of BCC Aquaculture Ctr.
I'm thinking to go through the samples one at a time, and capture each in photograph, and video if its interesting...



What's frustrating... it may take 25 or 50 or more shots, via exterior digital camera (using super-macro, to even get one good clear image through the lens of my microscope). Even these shots... the best of the batch, came out blurry. The software program which was included with the microscope I purchased is good, but it can never match the light, and quality of the real-life scene I'm seeing through the lens of the microscope. Capturing a high-focused, quality and true-to-life image, takes a lot of time, and needless to say, a lot of work.
-- ... then document more detailed information about the lifeform...
what it is, and what it does. This, along with so many other things I'm caught up in, like our final research project (I chose disection of a fish) and honestly haven't made the first crack at working on it [too many other things I'm wrapped up into] I have my schedule stretched out so thin, to do and accomplish so much, I emphasize aaaarrrrggghhh... I need more time to do it all.
I'm over-extended. But I really do love it. The Aquaculture center has so many interesting things going on it. I just sorted through some of my recent photographs, like this one of the crawfish the center has growing in a trough out in the hatchery.


So many interesting things to learn about, but so little time. College was definately the right choice for me, although I'm not the youngest student (mid-late 30's) but it's never too late to start learning something new. I just couldn't get enough information from the web, and I couldn't afford all the books on Amazon required to get where I want to be in my personal studies / hobbies. Our local meterologist George Elliot, WECT News 6 said, when you stop learning new things, you stop growing. So, it's never too late to get back into school.
My interest in marine biology has been growing since I first became interested in Cetaceans (whales, porpoise, dolphins) back in 2001, followed by a growing interest in mollusks, which developed from some trips to the beach and sifting through beachdrift... little creatures often taken for granted by tourists who walk right by, stepping on the shells and sometimes breaking them... which is bad, on the occasion, say an Angelwing, a very fragile shell washes up in one piece on the shoreline, and they do on a rare occasion. It dawned on me, each of the species I was looking at, have a unique story to tell. I began finding out what those stories are. Marine Biologist Terry K. Hathaway with NC Sea Grant has helped to identify most of those species, and I really have appreciated the input.

Right now, Algebra is what's dragging my schedule down. My Algebra instructor told me I should have taken his course, when not taking as many other courses -- making more time to focus on Algebra. But on a positive note, I'm about to complete another course that ends mid-term, and that may free up more time to devote to Algebra studies, at least hopefully, ideally...

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Freshwater Microscopy

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Two new items on the web.

John Baka, instructor at Brunswick Community College's Aquaculture Program shares photos of pests that affect North Carolina fish culture... fish eggs, and other great stuff.

John and Fish Eggs at BCC

Freshwater Microbes
Photos of microscopic organisms from a freshwater sample. Videos and images of freshwater algae and insects.

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Breeding fish at Kenyir Dam

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Company in project to breed fish at Kenyir Dam
R. S. N. Murali

A Negri Sembilan-based aquaculture trader has responded promptly to a call by Prime Minister Datuk Seri Abdullah Ahmad Badawi to the private sector to play its role in turning the National High Impact Aquaculture Industry Zone (ZIA) project into a successful venture.
T. Bitara Sdn Bhd of Oakland Commercial Park in Seremban will introduce state-of-art technology from China and Japan in freshwater fish breeding at Kenyir Dam soon.
The company’s chief executive officer Herman Nyam said the multi-million-ringgit project on a joint venture basis with a foreign company was expected to be initiated after the Chinese New Year celebrations.
“We will have a brand new start for the New Year creating job opportunities for locals,” he said after visiting the proposed project site at Kenyir Dam together with his director Shamsul Bahari recently.
Nyam said the company felt Terengganu was suitable for the introduction of the latest technology as the state was investor-friendly and willing to render assistance to businessmen at any time.
“We are looking at a technology which will increase the output of fish production in a short span of time and therefore we cannot afford to have red tape imposed especially in the licensing process,” he said.
Nyam said the company’s fish project at Talang Dam in Negri Sembilan had yielded robust growth since it was started five years ago.
“With the support of the Negri government, the fish is being marketed to China, Japan, Taiwan, the United States and India,” he said.
Nyam said that fresh graduates would be given the opportunity to manage the project in Kenyir Dam once the project was launched.
“These graduates will be head-hunted to manage the project and we expect to absorb 30 of them at the pioneer stage to manage our project,” he said.
Read the article in its entirety.

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Can fish farming save depleted cod?

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February 07, 2007
By Simon Rabinovitch
LONDON (Reuters) - Cod, a mainstay food from Britain to Brazil, all but disappeared from Canadian waters in the 1990s after years of overfishing, and scientists say a similar fate awaits the shoals of the North Sea.

But fish farms are putting cod back in North Sea water, at least within enclosed sea pens, easing the strain on wild fisheries and, fish farmers say, protecting a species that would otherwise be fished into extinction.

Off the Shetland Islands in northeast Scotland, Johnson Sustainable Seafoods is providing what it says is a model of good farming practice.

Given more space to roam around their pens and fed a natural diet, the Shetland cod farm has won the backing of Britain's Organic Food Federation.

"Fish farming can be the saviour," said Karol Rzepkowski, managing director of the company. "It takes a little bit of left-field thinking, having the right ethic and the right ethos, and it can be done right," Rzepkowski said.

RESTOCKING THE WATERS?

The Shetland farm expects to harvest 2,500 tonnes of cod this year and aims to double its output in 2008. Other producers include Pan Fish in Norway, which recently acquired Marine Harvest to become the world's leading fish farming group.

Much more is needed, though, if cod farming is help redress the decline in the wild population. Globally, the wild catch has plunged to about 1 million tonnes a year from 4 million in the 1960s. Stocks in northern waters, especially the Barents Sea, remain strong, but the World Wildlife Federation and others warn that overfishing is changing that.

Experts say it will be a long time before farmed cod production rivals the wild catch. "I don't think at this stage we are anywhere close to that," said Barrie Deas, chief executive of the Britain's National Federation of Fishermen's Organisations (NFFO).

Farmed cod will also be hard pressed to match the popularity of farmed salmon, more than one million tonnes of which were consumed last year, say aquaculture analysts at Norway's Kontali Analyze.

Salmon is better suited to aquaculture and its distinctive pink hue offers a marketing advantage over cod's white anonymity, Kontali Analyze noted.

TRULY SUSTAINABLE?

For now, attracting more attention than production figures is Johnson's claim that it is raising the world's first organic, sustainable cod.

One staunch opponent of the aquaculture industry is Bruce Sandison, chairman of the Salmon Farm Protest Group, based in Scotland. Barely pausing for breath, he reels off a list of problems: diseases have spread in crowded sea pens; farmed fish have escaped and damaged wild stocks; the farmed product is less healthful for consumers.

"The same thing is going to happen with cod," he said, pointing out that a disease called Francisella decimated about half the cod in a Norwegian fish farm in 2005.

"What we're playing with here is a wild species that has existed on the planet since probably the end of the last ice age. We're pushing that toward extinction, and we're going to replace it with a totally artificial species."

Questions have also been raised about the sustainability of fish farming. It takes a huge cull of smaller wild fish, about four tonnes worth, to feed every single ton of the captive population.

The Shetland farm has found a way around this problem. All its cod are fed with the "off-cuts" -- scraps destined to be discarded -- of wild fish already caught for human consumption.

"I doubt if that would be practical if the kind of expansion that is envisaged takes place," said Deas of Britain's National Federation of Fishermen's Organisations.

Aware of this limitation, researchers are beginning to consider alternative food sources, raising a distant prospect of truly sustainable fish farming. And if organic farms are also successful in curtailing harm to the broader environment, aquaculture could win over more of its critics.

"There would not be a lot left for us to moan about," said Tom Pickerell, a fisheries policy officer at the World Wildlife Fund-UK.

FROM SEA PEN TO TABLE

In the meantime, Johnson's Shetland cod has been able to lure a growing number of customers. Sold under the No Catch brand name, it is available in hundreds of Tesco and Sainsbury's supermarkets across Britain.

"It allows people to enjoy cod but without having any sort of guilty conscience about where that cod is coming from," said Joanna Keohane, spokeswoman for Tesco.

The avoidance of guilt is clearly a powerful influence in some markets: British shoppers are happy to pay a premium for the farmed cod over its wild brethren.

Copyright © 2007 Reuters, All Rights Reserved.

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Common Carp

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Notes from Fundamentals of Aquaculture, James W. Avault, Jr., Ph.D., pgs. 86-93

The common carp (Cyprinus carpio) is the longest and most widespread cultured finfish.

Common carp (Cyprinus carpio)
From Амурский сазан, Vertebrata
The common carp has been cultivated for 2400 years in China and 1900 years in Japan and widely distributed throughout the world. The common carp is farmed as far north in freezing regions such as the former Soviet Union and as far south as the Phillippines where it is cultivated in rice fields. In Austria, the Christmas carp is an important tradition and in many Asian countries carp serves as an important source of animal protein.

In 1965, Carp was recorded to have contributed 231,525 tons to the world fish supply, which excludes production in China which would exceed all combined figures. In all a total of 1.65 million tons of common and Chinese carp was grown there in 1965, but the last estimate could be half too low.

Through selective breeding, strains of carp have been developed over the centuries, including the leather carp and mirror carp. These two strains have remained in use, while others discarded. Carp breeding has continued around the world, with the mirror carp strain, now referred to as the "Israeli carp".

In China, a fully scaled strain of common carp, known as the big-belly carp, evolved, withstanding harsh environment of overcrowding and poor water quality. This fish strain is one of the few culture species which is considered truly domesticated.

The common carp was introduced in the United States in 1877, and is found today in 48 states. Though this species is prized in Europe and Asia, it has been considered by some to be a pest because it muddies water while foraging, intereferes with sportfish such as largemouth bass and the flesh contains numerous small bones. Some states have developed programs to regulate carp populations in reservoirs. Carp usually spawn in beds of weeds along shorelines, with the adhesive eggs sticking to vegetation, so one effective control method is by lowering the water level and stranding eggs after spawning.

Common carps are hardy, fast-growing and tolerant under adverse conditions with a prolific reproducers in captivity. The carp is a freshwater fish, but can tolerate up to 20 ppt salinity, and alkaline (acid water), not bothered by turbid water and grows on a variety of feeds including agricultural byproducts. Its biology and reproduction are well known making it easily farmed in a variety of culture systems. One expirament conducted by Szumiec (Poland, 1979) reported on common carp farming, with goal of producing 2.2 lb or larger. Stocking rates varied from 121-4047 per acre. Feeds included pellets and dough containing 25% protein derived mostly from plant origin, wheat used as a comparable carbohydrate feed and super pellets which contained 40% protein (primarily animal origin). The study lasted from April until the end of September and repeated for four years. Some fish reached as much as 3 lbs, and it was concluded ponds can produce 1786-2679 lbs per acre of carp with carbohydrate feeds, and 2679-5358 per acre with protein-rich pellets.

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NOAA 2008 Budget Request

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NOAA ANNOUNCES 2008 BUDGET REQUEST

Feb. 5, 2007 — Retired Navy Vice Adm. Conrad C. Lautenbacher, Ph.D., undersecretary of commerce for oceans and atmosphere and NOAA administrator, today announced highlights of President Bush's proposed 2008 budget for the Commerce Department's National Oceanic and Atmospheric Administration. Lautenbacher said NOAA's request totals $3.8 billion or an increase of 3.4 percent over the administration's 2007 request.

"The President's budget makes a substantial investment in our oceans that will pay dividends for years to come," said Lautenbacher. "We will be able to make great progress in the goals laid out in the President's Ocean Action Plan of ensuring sustainable use of ocean resources, protecting and restoring marine and coastal areas and enhancing ocean science and research."

Sustainable use of ocean resources + $25 million:
- Establish the regulatory framework for environmentally sustainable commercial aquaculture opportunities.
- Improvements for better management of aquaculture harvests.
- Support of the new and expanded requirements of the Magnuson-Stevens Management Reauthorization Act of 2006.
- Additional funding for observer programs and market-based approaches to fisheries management.

News Audio (mp3)
NOAA Administrator Conrad Lautenbacher media teleconference briefing in Silver Spring, Md., on NOAA 2008 budget request.

Support for the President's U.S. Ocean Action Plan

- Protection and restoration of marine and coastal areas + $38 million
- Enforcement and management of the newly designated Northwestern Hawaiian Islands Marine National Monument.
- Funding to restore nearly 1,000 stream miles for endangered Atlantic salmon and other species.
- Klamath River salmon recovery.
- Competitive grant programs focused on the Gulf of Mexico Alliance coastal resource priorities.

Climate Monitoring and Research

- Support for the National Integrated Drought Information System +$4.4 million.
- Support for the U.S. Integrated Earth Observation System +$0.9 million.
- Research to understand the link between ocean currents and rapid climate change +$5 million.
- Enhance computational support for assessing abrupt climate change +$1.0 million.

Read the Entire Story at NOAA News Online

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Aquaculture in South Africa - Farming Endangered Abalone

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'Abalone farming has the highest economic value as compared to all other farmed products'

Known in South Africa as "perlemoen", abalone is so endangered the government has drastically reduced the total allowable catch in the wild and attempted to encourage saltwater farming of the curlicue-shaped shellfish.
Resembling a giant limpet and a distant relative of garden snails, it thrives only in oceans or special land-based farms that use seawater to cultivate the creatures.

'The amount of illegal abalone confiscated in South Africa has skyrocketed'
Abalone's growing popularity in Asia, where it is a status symbol and reputed aphrodisiac, has spurred sophisticated smuggling rings, some linked to China's notorious Triad gangs, according to South Africa's Institute of Security Studies.

The amount of illegal abalone confiscated in South Africa has skyrocketed to more than a million shellfish from a mere 21 000 in 1994. It is now common for police to pull over trucks, sometimes refrigerated, carrying illegal abalone on the roads of the Western Cape and Eastern Cape, where most of the delicacy is harvested. "We've had good successes, especially towards the end of 2006, where we seized huge quantities of abalone - this is just the tip of the iceberg," said Captain Billy Jones, a spokesperson for the Western Cape provincial police. But legitimate businesses also see a future in abalone farming in South Africa. 'Abalone farming has the highest economic value as compared to all other farmed products'
Production accounts for 60 percent of the country's aqua-culture revenues. In 2006 it was worth more than R141-million and employed about 800 people.

"Abalone farming has the highest economic value as compared to all other farmed products and is the highest employer within the marine aquaculture sector," said Blessing Manale, spokesperson for South Africa's department of environmental affairs. He said the department hoped job losses in shrinking abalone fishery could be offset in the burgeoning farm-raised sector, which in 2006 produced more than 900 tons of abalone and is projected to hit the 1 000 ton mark in 2007.

Read the entire article SA caters to Asia's craving for 'perlemoen', News for South Africa (February 06 2007 at 11:44AM)

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