Identification of optimal husbandry factors improves survival and growth of larvae and juveniles

A protocol for larval-rearing of pikeperch, which identifies an optimal combination of factors, has been developed to give best growth, survival and development of larvae over the nursery period.

“Progressively, the rearing protocol for pikeperch larval rearing was improved, and an optimal combination of factors was determined. It allows the production of 5,000 juveniles (1.0-1.4 g, 50 dph) per 700-liter tank with swim bladder inflation rate of 90-95%,” cited Pascal Fontaine et al in Improvement of rearing conditions for juvenile pikeperch (Sander lucioperca) production in RAS.

Reliable protocol

A global and multifactorial approach sets it apart from previous studies conducted on the topic.

“Our objective is clearly to identify an optimal combination of factors and to propose a reliable protocol for fish farmers. It is very much an applied research. We consider the larval rearing tank as a complex system. Our research considers the whole larval-period of seven weeks. We are not focused on a specific event, such as first feeding, weaning or growth after weaning.         

“We would like to identify a global combination of environmental, feeding and population factors that will produce a maximum of juveniles well-developed in terms of higher growth, survival and swim bladder rates. We use a pilot-scale 10 m3-RAS, very close to those met on farm conditions,” Fontaine told Hatchery International.

Fontaine is director of the Research Unit Animal and Functionality of Animal Products, University of Lorraine – INRA in France. The project received funding from the European Union’s Seventh Framework Program for research, technological development and demonstration.

Some of the major bottlenecks in larval-rearing have been identified ashigh mortality due to cannibalism;high occurrence of skeletal deformities; andlarge size heterogeneity between larval cohorts at various ontogenic development stages.

Three experiments

Three successive experiments studied the effects of major environmental, nutritional and population factors.

For each trial, pikeperch larvae were distributed in eight 700-liter tanks from an indoor water-recirculating system.

Four environmental factors were tested in the first experiment. These were light intensity; water renewal rate; water current direction in the tank; and cleaning done at two different periods of time.

The study recommended an application of “a light intensity of 50 lx, a water renewal rate of 100%, cleaning of the tank during the afternoon and an inlet of water at the bottom level.”

In the second experiment, four nutritional factors were studied including method of food distribution; co-feeding; and weaning duration. Results showed that “a later onset and longer duration of weaning followed by discontinuous feeding improved larval survival, growth and reduce skeletal deformities in pikeperch populations.”

The third experiment focused on four population factors: initial larvae density; sorting out fish jumpers; sibling or not sibling populations; and female weight. Results suggested “an improvement of juvenile pikeperch production using initial high larvae density supplied by large females.”

“We need to reduce production costs and develop a breeding program,” Fontaine said.

One of Australia’s leading warm water fish hatcheries, located in the Eastern Riverine region of New South Wales,produces Murray cod, silver perch and golden perch for domestic and export markets.

The proprietor of Murray Darling Fisheries, Noel Penfold, spent several years in the industry before branching out on his own, and it took him several more years finding the right property.

“Water quality is everything in aquaculture, especially in a hatchery. Our bore water comes out at 20ºC and has a carbonate hardness buffer of 70ppm. The topography is just right for pond culture: the ground holds water and we’ve got 3-phase power going past the front door,” he said.

Noel is an irrigation engineer and designed and built the hatchery and ponds himself. The farm has 64 ponds covering 9.25ha. Sizes vary: thirty-six (1.5m deep) are dedicated to fry production and another 28 (2.5m deep) are dedicated to broodstock.

The hatchery and nursery facility is spacious, and all air and water plumbing runs either along the walls or overhead, which makes manoeuvring trollies and graders much easier.

The main and most labour-intensive crop is cod (Maccullochella peelii peelii). Thirty to forty spawning pairs are held in each broodstock pond, and in total MDF holds between five and six hundred brood-fish. Their largest fish was 35kg when last weighed, (the heaviest caught in European times weighed 93kg, but there are fossil skulls of fish at least twice that size!)

Spawning Murray cod

Spawning drums are put into the ponds in late August and spawning commences during the last week of September. Farm manager Leigh Logan theorises that photoperiod triggers spawning more than temperature.

“The start of spawning doesn’t vary that much, even though water temperatures do. It’s never later than the first week of October, when temperature can be 16ºC.”

Water temperatures have a bearing on the duration of the season: sometimes it’s over by the first week in November; but in a cool spring spawning can be strung out till the first week in December. Regardless of the duration of spawning, they get 350-400 viable spawnings yielding 3.5million larvae each year.

Three-pronged market

The market for juvenile cod is three pronged, which determines the procedure from this point. One market, mainly for export, is for yolk-sac fry. They pack 10,000 in a polystyrene box, and although the fry have to be weaned on arrival, the economics pay off when freight and handling costs are considered.

Local commercial clients usually prefer to buy weaned fingerlings. In this case, the fry are stocked into plankton ponds that have been freshly flooded 10-15 days prior to liberation. As the bore water is 20ºC pond temperature is not a problem, although Noel admits that producing a plankton bloom early in the season, when temperatures fluctuate between night and day, can be problematic.

The ponds are dosed with sufficient agricultural lime and dolomite to bring the carbonate hardness up to 120ppm, scarified and then fertilized with lucerne hay, urea and phosphate. The plankton bloom is managed with 10hp of paddlewheel aeration per hectare when necessary. Evaporated water is replaced, which keeps the hardness buffer at acceptable levels, as well as keeping the ponds fresh and well stirred.

After six weeks the fry measure 25-30mm and are brought into the weaning shed. All fingerlings that come in from the ponds receive a formalin dip to remove any ectoparasites.

Feeds and feeding

They’re fed brine shrimp (Artemia), and weaning onto dry starter crumbles commences on day three. The price of brine shrimp eggs is high; they use six tins a day at $170 each. (Leigh pointed out that their Asian clients pay considerably less for brine shrimp, which is another reason they purchase yolk-sac larvae). Weaning is painstaking — it takes from 10 to 15 days — but they’ve got it down to a fine art and Leigh said they achieve 95% success.

While genetic improvement at this stage has been restricted to the selection of better performing fish for the broodstock ponds, MDF improves its seedstock performance by culling approximately 30% from the bottom of each cohort before they go to their grow-out customers.

“It’s a numbers game, I know,” said Noel, “but if you can identify and eliminate the slow growers as early as possible, they’re numbers that add up down the track in the growout farms.”

MDF is a member of the Hatchery Quality Assurance Scheme. To ensure biodiversity in public water restocking orders the broodstock must come from the catchment area of the intended liberation, and the fingerings have to be held until they’re 45-50mm, however, they don’t need to be weaned.

Noel recently withdrew from the NSW Fisheries dollar-for-dollar restocking program. He evaluated the new compliance requirements imposed by the department, particularly those associated with the occupational health and safety responsibility covering angling club members, and found the insurance costs too high and the risk outside of his control.

Broodstock maintenance

The cod broodstock are left alone in their respective ponds. Leigh reasons that the fish have developed their hierarchy and as their feeding regime is a controlled mixture of maintenance pellets and trash fish, the ponds’ biochemistry keeps the water quality stable. Constant observation ensures nothing untoward catches them out, and evaporation replacement keeps a steady water exchange through the ponds.

Chilodonella [a ciliated protozoan ectoparasite] is the only thing we have had to treat, and… it’s quite a straightforward operation,” he said. “We dose the pond with a mild formalin dilution, apply vigorous aeration and exchange the pond water throughout the treatment. The treated water goes to the settlement pond water where the biodegradable formalin breaks down under aeration and sunlight. Keeping the ponds healthy is the secret. We rarely have to treat the fish.”

Spawning perch is different

The perch spawning season overlaps that of the cod, although the methodology is very different. Egg maturation is temperature-triggered. They’re ready from December to January when pond temperatures are around 24-25ºC. The ponds are lowered and the broodstock netted.

Golden perch (Macquaria ambigua) females showing heavy ovaries and red swollen vents are injected with 500iu/kg of pregnyl, and males with 250iu. After injection, five males and two females are stocked in a gently aerated 1,500-l tank. Ovulation takes 36-48 hours. The fertilized eggs are netted into a clean flow-through tank. Incubation takes around three days and yolk sacks are depleted in another five. Plankton blooms only take 5-7 days to establish at this time of year. After 6-weeks in the ponds the larvae are 25-30mm. Another fortnight sees them coming out of the ponds at 35-40mm and much deeper in the body. The process for silver perch (Bidyanus bidyanus) is pretty much the same, except the hormone dose rate is lower — 200iu/kg — and only the females are injected.

Leigh again: “Initially, a batch of cod can take nearly a month to put through the system; longer if they have to be weaned. The perch are all done and dusted in a week.”

The changes to the native fish hatchery industry over the 25 years during which Noel has been involved have been major. The industry participation rate has declined while the industry itself has grown enormously. Farm dam stockings, once important, have been replaced by sales of seedstock to local commercial growers and producers in East and southeast Asia. The demand for high volumes has seen operations like MDF producing millions of fry and fingerlings, which has helped finance expansion and structural changes, to the point where a hatchery can be run comfortably by two people with some casual help at the height of the season.

For more information contact Noel Penfold at This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Side Bar

Two different markets

The markets for the two lines of fish are also markedly different. Export cod have to be bagged and boxed, the inspection requirements have to be complied with, export paperwork submitted, certificates issued at both ends, and regular farm and catchment health audits carried out. In the case of MDF, the catchment audit is not a problem as no water comes onto the farm, and none leaves it. Noel attributes the reports of the quality of his seedstock from buyers to the healthy start they get at the hatchery. Weaned fish sold locally can be transported in bulk in aerated tanks but they still have to be weaned, graded and delivered.

Golden perch, also known as callop and yellow belly, are a prized eating and angling fish. Their market is for the private- and public recreational trade. Silver perch sales are mainly to government stocking programs and a small growout industry based on the live fish markets in the east coast capital cities. They’re delivered in tankers directly from the ponds for both public and commercial stocking.

The Russian company Ivanovo Compound says that it has invested Rub17 million (US$250,000) into a new facility for breeding African marble catfish in Nizhny Novgorod.

Sergey Feflov, general director of Ivanovo Compound, said that the company had already concluded preliminary agreements to supply fry to several regions bordering Nizhniy Novgorod Oblast, plus to fish farms in the remote regions of Siberia.

The company intends to build a feed mill, producing products specially designed for the dietary needs of African catfish. In this way it can provide its partners with fry, feed and support when it is needed.

Ivanovo Compound’s business strategy relies in part on forecasts by the Russian Aquaculture Producers Association, commonly known as Rostybhoz, which indicate that several dozen farms for rearing African catfish may be established in the country, with potential production up to 40,000 metric tonnes.

If that forecast comes true, then the demand for fry would be significant.

African catfish is widely used for production of various pates, fish sticks, dumplings and in some cases even baby food.

Belgium’s TomAlgae, which specializes in freeze-dried algae for use in shrimp and oyster hatcheries, is aiming to ramp up export of its products to U.S. hatcheries. To help accomplish this, TomAlgae contributed one of 11 prizes in the ICX (Industry Connection) competition at the 2017 Fish 2.0 contest.
Having a consistent and reliable source of seed remains ons of the biggest issues facing oyster producers in the US and Canada.

Even the region's largest grower is not immune to it.  Having a consistent and reliable source of seed is a perpetual problem, Bill Taylor, the president of Taylor Shellfish based in Washington State, told Hatchery International earlier.

In the Canadian west coast, farmers are faced with the same problem, according to  Keith Reid of Stellar Bay Shellfish.

“We don’t have enough production capacity here right now. We have several hatcheries that are expanding and I buy some product from every one of them to spread out the risk,” Reid says.
He plans to buy 60 million seeds this year. “I couldn’t risk the chance that one or two growers might run into a problem and couldn’t deliver.” For that same reason Reid says he wouldn’t build or rely on a hatchery of his own.  He says he is buying about 50 percent of his seeds from Chile.
West Virginia’s White Sulphur Springs National Fish Hatchery expects to resume supplying rainbow trout eggs to hatcheries in 14 states in 2019.

Flood waters damaged the US Fish and Wildlife Service facility in June 2016. Most of the physical damage has been repaired; the hatch house has been cleaned out and disinfected. However, another year and a half remains before the hatchery can fully resume its primary mission of supplying eggs because the facility requires a full three years to come up to speed, reported the West Virginia Gazette Mail.

It has taken more than a little adjustment on the part of the hatchery’s staff to get over the effects of the flood — not just to oversee repairs to all the damage, but also to grow a brand-new population of trout, the paper reported.

“We won’t be completely back to normal until 2019, but we’re getting there,” Tyler Hern, White Sulphur’s lead fish biologist, was quoted as saying.
New York State Governor Andrew Cuomo has announced that the state will put $10.4 million into restoring shellfish populations around Long Island.
A new hatchery in the Republic of Karelia, Russia should help establish self sufficiency for the aquaculture sector in that part of the country, according to regional governor Artur Parfenchikov.

The new facility will focus on the production of trout fingerlings and trout caviar, he added. Both products are in high demand in Karelia, but local aquaculture farms have to import it, primarily from Norway, because the two hatcheries currently operating in the republic are producing fingerlings only for recreational purposes and not in sufficient quantities.
A collaborative effort between the Centre for Environment, Aquaculture and Fisheries Science (Cefas) and the University of Exeter was launched in late October by Secretary of State for Environment, Food and Rural Affairs, Michael Gove. The intent is to bring together world scientists “to ensure the key challenges facing sustainable growth of the aquaculture industry are better understood, both at home and internationally.”
The large-scale production of farmed fish along the Norwegian coastline results in large amounts of sludge each year. The sludge is a mixture of fish feed and faeces. Non-removal of the sludge can lead to toxic algal blooms and poor water quality for the fish. But the sludge also contains chemicals such as phosphorus, which can be used in fertilizer production for land-based farming, and can be converted into biogas for use at land-based hatcheries.
Scientists with the University of Southern Mississippi and staff at the Perciformes Group, based in Rockport, Texas, will focus on developing facilities and appropriate protocols for breeding and developing premium-quality tripletail (Lobotes surinamensis) for the retail and restaurant markets.
With huge contributions to the livelihood, employment and food security of coastal communities in Nigeria, the fisheries sector is one of the country's most important. Amidst a high demand for quality catfish seed, one hatchery in Ughelli Delta State could have significant impacts on Nigeria's aquaculture.
Through a grassroots approach, a USAID-funded program is offering a solution for sub-Saharan Africa’s fish farmers’ perennial problem of sourcing catfish fingerlings.
Octopus or tako, in Japanese, is a special ingredient in Japanese food culture. There are over 250 different species in the world with roughly 60 caught in and around Japan. Two thirds of the world's share, or 160,000 tons, is consumed every year in Japan as sushi, sashimi, tako-yaki balls and western-style dishes.
A hatchery for the production of four million sterlet (Acipenser ruthenus) fry per year will be built in the Republic of Tatarstan, Russia according to Ilya Shestakov, chairman of the Russian Federal Agency for Fisheries (Rosrybolovstvo).
Page 10 of 25

Subscription Centre

New Subscription
Already a Subscriber
Customer Service
View Digital Magazine Renew

Most Popular

Latest Events

The Fish Site seminar
Wed May 29, 2019 @ 1:00PM - 05:00PM
Aqua Nor
Tue Aug 20, 2019
Aquaculture Europe 2019
Mon Oct 07, 2019

We are using cookies to give you the best experience on our website. By continuing to use the site, you agree to the use of cookies. To find out more, read our Privacy Policy.