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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Teaching a man to fish...

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Today I visited the local fish market for "fish heads" to do part of my fish dissection project. I want to investigate how the brain of a fish works and interconnected. They were very kind and supplied me with a bag full of fish heads, on the house. *smile*

I saw they had this neat bumper plate in the window.

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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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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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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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Marine Aquaculture Task Force Suggests Regulating Aquaculture

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Woods Hole, MA -- Congress should enact legislation to ensure that strong environmental standards are in place to regulate the siting and conduct of offshore marine aquaculture, according to an independent panel of leaders from scientific, policymaking, business, and conservation institutions. At the same time, the Marine Aquaculture Task Force suggests that the federal government should provide funding and incentives for research, development, and deployment of technologies, and techniques for sustainable marine aquaculture.
Aquaculture is the farming of fish, shellfish, and aquatic plants, and it accounts for nearly one half of all seafood consumed in the world today. The industry is growing rapidly as wild fish stocks decline.

The Task Force—-organized by researchers from the Woods Hole Oceanographic Institution (WHOI), with support from The Pew Charitable Trusts and The Lenfest Foundation—-was charged with examining the risks and benefits of marine aquaculture and developing a set of national policy recommendations to guide future development of our oceans.

Members of the panel have been meeting since the summer of 2005, and they released their findings in a media conference call. View full report -- Sustainable Marine Aquaculture: Fulfilling The Promise; Managing The Risks.

“There is a growing need for seafood to feed a hungry world, but the world’s fisheries can no longer meet the demand,” said task force chairman Rear Adm. (ret.) Richard F. Pittenger, former WHOI vice president for Marine Facilities and Operations and a former Oceanographer of the Navy. “Half of our seafood comes from aquaculture, and that share is only going to grow. The federal government has proposed a fivefold increase in U.S. aquaculture production, and while we certainly agree with an increase, we believe it must be done in an environmentally responsible way.”

Read the rest of this story at Pew Charitable Trusts News Release

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Lowering pH Levels in Water

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As a follow-up to my earlier post, on pH levels and water

Water samples which indicate a high pH level when tested, could be adjusted by straining water through peat. The instructor at BCC compared it to "tea," which is dark, but safe for fish. Added to the aquarium, the pH level was brought down within a safe range.

Here's John straining the brackish water.

Large debris are removed by hand, then strained through a fine net tightened down with a bungee cord (pulley) on a large bucket.


Brackish water, (low pH solution added to one of the empty tanks). John (instructor of Aquaculture Practicum at BCC) warned it wouldn't be good for fish to be swimming in their tank and suddenly the pH drops an entire point, so the transition is accomplished gradually.

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Which Fish Do Fast Food Restaurants Use?

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McDonalds' Fish Filet Sandwich
The Filet-O-Fish is a fish sandwich sold by McDonald's since 1963. It contains a breaded fish patty made from Pollock or Hoki.
Source, 1 and 2

Alaska pollock is commonly used in the fast food industry, for example the fish filet at both McDonald's and Burger King are also made from Alaska pollock.
The Alaskan pollock is said to be "the largest remaining source of palatable fish in the world." Atlantic pollock is largely considered to be a white fish, although it is a fairly strongly flavored one. Alaska pollock has a much milder taste, whiter color and lower oil content. (Pollock, Wikipedia)

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