Aquaculture Research at the
ST. ANDREWS BIOLOGICAL STATION

Aquaculture has increased steadily in recent decades in an effort to provide fish protein to the growing worldwide population. In the Maritimes Region, aquaculture has also become a major economic and fisheries activity. Species currently cultured include mussels, scallops, Atlantic salmon, Atlantic halibut, trout and striped bass.

Research at the Biological Station in the late 1970s led to the development of the Atlantic salmon aquaculture industry in the Bay of Fundy. This industry is now valued at almost $200 million annually, with a production of approximately 35 thousand metric tonnes.

Research on Atlantic halibut and haddock at the Biological Station in the late 1990s has also been transferred to industry. Halibut culture is in the commercial development stage and the prospects are encouraging. Haddock culture is still in the experimental stage, and is a primary focus of research at SABS.

The Aquaculture Division supports developmental research on shellfish species such as sea urchin, scallop, and clam, and collaborates with other divisions on studies of aquaculture-environmental interactions. Through this work, the Aquaculture Divison helps ensure that that aquaculture develops in an environmentally sustainable manner.

For more information:
Section Head: 
Dr. Dave Aiken
531 Brandy Cove Road
St. Andrews, NB E5B 2L9
Tel: 506-529-8854; Fax: 506-529-5862 

MARINE FISH CULTURE

Commercial marine finfish culture in Atlantic Canada is focused almost exclusively on Atlantic salmon. The hazards of basing an industry on a single species have been apparent for years, but no suitable alternative species has emerged. Two marine finfish species now show potential - the haddock and the Atlantic halibut. Earlier halibut research at the St. Andrews Biological Station (SABS) provided a foundation for commercial halibut production at three private hatcheries and growout sites in the Maritimes. 

Under the direction of Paul Harmon, researchers at the Biological Station are now exploring the culture potential of haddock. Eggs, food and fish are combined in a continuous production stream in the Finfish Production Facility. This approach allows research staff to assess any biological and technological constraints that exist in the current culture technology, and refer them to multidisciplinary research teams for resolution. A private company is currently evaluating the commercial potential of haddock at local growout sites. 

Five-gram juvenile culture haddock in the St. Andrews hatchery. 

Recent haddock research emphasis at the Biological Station has focused on nutrition and food technology. The nutritional requirements of larval haddock are not well known, and deficiencies can reduce survival rates and cause developmental problems. This year, Artemia will be incorporated into the larval feeding regime, and the team will expand its research on the development of microdiets. A nutritionally adequate microdiet could be substituted for the live feeds currently required, greatly reducing production costs. 

Timing of egg production is another area of research focus for the Marine Fish Culture project. Natural egg production occurs during a relatively brief period, producing a pulse of fish in the hatchery and nursery. Photoperiod and temperature can be used to accelerate or retard the reproductive cycle of adult broodstock, thereby extending the spawning period throughout a larger part of the year. Eventually the team expects to have broodstock on egg-production cycles that are advanced by three, six and nine months. 

ATLANTIC SALMON CULTURE

Atlantic salmon culture research at SABS is conducted under the direction of Dr. Brian Glebe, with the assistance of Paul Harmon and Wilfred Young-Lai. Many of the projects conducted in this program are carried out in collaboration with industry and university partners. 

S0 ("S-zero") smolts have been transferred experimentally to seawater cages each November since 1999. The first harvest and evaluation of these transfers will take place this winter. In parallel, we are evaluating an alternate strategy that would produce 25-gram S0 "super smolts." 

Annually since 1998, an industry-supported quantitative breeding program has produced 100 families of Atlantic salmon. Individuals from the best families, identified by a selection index for specific traits, are being bred to concentrate favorable genes in subsequent generations. To complement the quantitative breeding program, DNA molecular markers (microsatellites) are being used to maintain pedigrees and eliminate inbreeding. 

The Saint John strain of Atlantic salmon is the only strain permitted for commercial culture in New Brunswick, and early maturation (grilsing) in seawater and growth to harvest weight has been variable in this strain. Sterile triploid (extra chromosome set) all-female stock of Quebec origin are being compared to the diploid Saint John stock. Preliminary results indicate growth to the smolt stage is superior in the Quebec strain. Information on grilse numbers and survival and growth in seawater cages is pending. 

The industry annually vaccinates more than 9 million Atlantic salmon smolts against a variety of pathogens, but vaccines against Infectious Salmon Anemia virus (ISAv) have produced variable results. Short-term laboratory research (up to 800 degree-days post vaccination) indicates survival is improved in vaccinated fish compared to unvaccinated fish, but longer-term trials (up to 2000 degree-days) are needed. 

SHELLFISH CULTURE

The Shellfish Culture program, under the direction of Dr. Shawn Robinson, is developing culture techniques for the green sea urchin, the blue mussel, the sea scallop and the soft-shelled clam. For the past seven years, Dr. Robinson, Jim Martin and their collaborators have been developing enrichment diets for the sea urchin. The objective is to enhance the quantity and quality of roe obtained from commercially harvested urchins. During this same period, the world sea urchin harvest has declined by 20-25%, forcing the industry to generate more money from a smaller number of urchins. One solution is to produce sea urchins in a hatchery-based system and increase both the quantity and the quality of the roe they produce. Diets produced by Dr. Robinson in collaboration with DFO nutritionist Dr. John Castell and their associated industry partners have out-performed the natural diet of sea urchins. These studies have shown that dietary manipulation can increase roe quantity from 10% of body weight to as much as 35%. Their research is now focused on improving roe quality as well. 

Researchers evaluate the quality of sea urchin roe produced on experimental diets. Top-quality roe is plump and golden yellow-orange in color (inset). 

In 2001, the group began evaluating the potential of integrated culture involving blue mussels, kelp and Atlantic salmon. Ideally, the mussels will utilise organic matter from the salmon feed, the kelp will absorb nutrients excreted by the salmon, and the salmon will benefit from the improved water quality. This work involves four graduate students and is being done in conjunction with scientists from the University of New Brunswick. 

Scallop culture research consists of three main thrusts. The first explores how the early life stages are linked to the environment. This allows industry to use sophisticated tools such as satellites to find scallop spat. The second is looking for the best grow-out technology for taking the scallops to a marketable size or to a smaller size for release. The third is studying the biofouling that settles on cages and nets. Recent experiments have identified some of the harmful species involved and explored the possibility of using other species to control the biofouling. 

BROODSTOCK MANAGEMENT

The broodstock program, led by Debbie Martin-Robichaud, is responsible for the production of high quality halibut and haddock seedstock for research by university, government and industry, and for the development of improved broodstock management techniques for new finfish aquaculture species. 

Martin-Robichaud and assistant, Stephanie Warrington, are currently working with scientists at the University of New Brunswick and the National Research Council to develop all-female stocks of cultured halibut. Growth studies on halibut indicate that juvenile females grow faster and mature later than males. These are important factors in increasing the economic benefit to potential growers. The team is also conducting "gynogenetic studies" to identify the mechanism that controls sex determination in halibut. The goal is to get mature male halibut broodstock to produce feminized milt or sperm. Inseminating females with this feminized milt will result in all-female offspring from marketable fish without the use of invasive hormonal treatments. Studies are also being done to determine if environmental or biochemical factors such as temperature and aromatase inhibitors can be manipulated to alter the number of female halibut produced under culture conditions. In addition, the team is using the tools of molecular genetics, such as DNA fingerprinting, to identify the pedigree of all cultured Atlantic halibut broodstock maintained in Atlantic Canada. This is important for the prevention of inbreeding and the development of genetic selection programs. 

MARINE FISH PHYSIOLOGY

Marine biologist John Martell is studying the effects of egg-incubation temperature on the development and growth of haddock through the juvenile stage. Temperature during incubation can significantly affect development, metabolism, and growth, particularly of 

Haddock embryonic development from two days after spawning (upper right) to hatching of the larvae (lower right). 

muscle, and this effect can be followed throughout the life of the fish. Using image analysis, Martell monitors gross structure, development, and cellular and tissue organization of the fish. Differences in metabolic and biochemical function are being determined for all life stages through examination of various aerobic and anaerobic enzymes and metabolic products. This research will help define how temperature affects the production of white muscle, a major component of the body mass of a fish. 

ENVIRONMENTAL BIOLOGY

The Aquaculture Division´s mandate includes sustainable aquaculture. Susan Waddy and her assistants Natalie Hamilton and Sarah Mercer have developed a sustainable aquaculture component under the Environmental Biology project. The primary focus of the project is the influence that environmental factors have on the development, growth and reproduction of cultivated species, but the team also conducts multidisciplinary research on the impacts of aquaculture chemo-therapeutants on the environment, including non-target organisms that have commercial value. These studies are conducted in collaboration with the Marine Environmental Sciences Division. 

Current work includes the sublethal effects of aquaculture chemicals such as azamethiphos (the active ingredient in Salmonsan®) and emamectin benzoate (the active ingredient in Slice®). These are used by the salmon industry to eliminate sea lice, a serious parasite of salmon. The assay organism for these studies ­the American lobster­ is ideal because it is commercially valuable and its biology is well known. The project will determine whether chemicals can act synergistically with natural environmental factors to disrupt important biological processes in lobsters. 

Lobster being hand-fed in a research study. 

An important focus of the study is whether an organism´s response to a chemical can vary with the time of year. Chemicals that cause sublethal effects at one time of the year may have no effect at another. This is important information for risk assessment. Preliminary results indicate lobsters may be less sensitive to azamethiphos in the autumn than in the spring. 

Information gained from these studies is being used by the aquaculture industry in the therapeutant-approval process. This information is also used by the government in responding to concerns from the public and the fishing industry regarding aquaculture impacts. 

BIOTECHNOLOGY

Dr. Edward Trippel and assistant, Steve Neil, apply biotechnology in support of commercial finfish aquaculture development in Atlantic Canada. Pedigree development and strain selection are important for successful commercial aquaculture, and the potential of haddock as a commercial aquaculture species has prompted a search for the best combination of traits for intensive culture of this species. Trait heritability factors of 0.2 to 0.3 indicate that attempts to improve growth and survivorship in this species through strain selection will be successful. 

NUTRITION RESEARCH
 

The Nutrition Program, under the direction of Dr. John Castell, provides nutritional information and research on established and prospective aquaculture species such as Atlantic salmon, haddock, halibut and sea urchin. Dr. Castell, his assistant Tammy Blair, and associated graduate students have conducted feeding trials to establish the nutritional requirements of these species and to analyze the nutrient composition of natural foods of species that are important to aquaculture.

Recently, a six-month feeding trial was conducted with Atlantic salmon in which the fish meal was replaced by a high-quality crab meal. Increasing levels of crab meal were found to produce a corresponding increase in salmon fillet pigmentation, feeding efficiency and growth rate. A similar study will be conducted with juvenile halibut. The crab meal was also found to be an acceptable supplemental protein source in diets used to enhance roe production in sea urchins, producing roe with good flavour, colour and texture.

Experimental diets used in nutrition studies are produced with a Hobart extruder (above left) and then fed to sea urchins (above) and other test animals to assess nutritional value.