Biological station keeps innovating in aquaculture

Atlantic Canada’s oldest fisheries-research station is helping to shape a new industry. The St. Andrews Biological Station in Passamaquoddy Bay, New Brunswick, on the Bay of Fundy, began groundbreaking work on salmon aquaculture in the 1970’s. Among highlights in following years, researchers developed new methods for farming groundfish such as haddock and halibut. Now, they are looking into the future with polyculture, in which different forms of aquaculture reinforce one another.

Salmon aquaculture: The Norwegian scientists who first farmed Atlantic salmon drew on physiological research from the St. Andrews station. In turn, station scientists in the 1970’s drew on Norwegian experience to pioneer salmon aquaculture in Passamaquoddy Bay.

After working out initial methods with private-sector and provincial government partners, researchers such as Arnold Sutterlin, Richard Saunders, and Dick Peterson kept improving techniques. For example, research showed that changing the daily exposure to light in hatcheries could speed the salmons’ development to the smolt stage, when they can live in salt water. Station scientists researched nutrition and other factors and outlined best practices for the rapidly expanding new industry.

More recently, Paul Harmon and Brian Glebe have helped aquaculturists to use light exposure at cage sites to influence growth and maturation. The station has also helped in the testing of salmon vaccines, especially against Infectious Salmon Anemia (ISA).

Using genetic analysis or “DNA fingerprinting,” St. Andrews scientists working with university researchers have identified genetic markers associated with different salmon traits. For ecological reasons, salmon farming in southern New Brunswick must rely on broodstock originating in the Saint John River only. Understanding genetic markers will help the industry to breed superior individuals together, improving growth and resistance to disease.

The station continues to foster an industry providing one job in four in the Passamaquoddy area, and yielding salmon worth about $180 million in 2003, even before processing or other added value.


Salmon cages in Passamaquoddy Bay. (Photo courtesy of Shawn Robinson)

Much of the salmon and other research has taken place in co-operation with partners from the private sector, universities, the provincial government, and other agencies including the National Research Council (NRC).

Groundfish aquaculture: As salmon farming increased, station scientists diversified into other marine fish. Groundfish, white-fleshed species such as halibut, cod, and haddock, are a valued food item in many countries. Researcher Ken Waiwood did pioneering work on both halibut and haddock. The St. Andrews station developed broodstocks for both species that provided the foundation for commercial hatcheries during the past ten years.

Few halibut broodstock were available at first. Wild stocks were low, and holding the large Atlantic halibut – about 15-20 kg and more than a metre long at maturity – took considerable space. The small number of broodstock increased the threat of inbreeding. Biological station scientist Debbie Martin-Robichaud and colleagues at the NRC’s Institute for Marine Biosciences in Halifax, Nova Scotia, began using genetic markers to identify related halibut and prevent the mating of siblings.

The same DNA techniques let them detect gene and chromosome patterns associated with desirable traits such as larger size. A small tissue sample can show which halibut the industry should breed for best results.

In another twist, researchers set out to improve growth by producing more female halibut, which grow faster. By exposing young halibut to certain natural chemicals, they create “neomales” whose milt, or sperm, produces only female offspring.
 

Stripping milt from a halibut. (Photo courtesy of Debbie Martin-Robichaud)

The station and its research partners have built up an array of halibut-culture tools and techniques unmatched in the world. Work is also going forward on haddock and cod. If market and other factors bring a buildup in groundfish aquaculture, the biological station will have helped lay the foundation.

Integrated aquaculture: In 2002, scientist Shawn Robinson, together with Thierry Chopin of the University of New Brunswick and a team of other scientists and industry partners, began working on polyculture. Mussels and kelp growing on salmon cages were a nuisance. Research found ways to turn them into a benefit.

Leftover food and natural waste from salmon cages produce an underwater rain of nutrients, both organic and inorganic. The researchers put rafts near cages and suspended lines bearing juvenile mussels, or “spat,” and tiny kelp (a type of seaweed).

They found that both grew nearly 50 per cent faster than in ordinary conditions. And with the filter-feeding mussels taking up organic matter and the kelp consuming inorganic nutrients such as nitrogen and phosphorus, waters at the cages stayed cleaner.

“It gets down to recycling,” Shawn Robinson says, “with a market benefit.” The cage-site mussels can get to the minimum commercial size in eight to ten months, far faster than in regular mussel farming. Providing the shellfish pass food and safety standards, they can go to the restaurant and retail trade. Kelp has markets in food, nutriceutical, and other applications.

In aquaculture, the move from concept to full-scale commerce can take years. The promising new venture into polyculture needs to build more scientific data and to work out operational matters, such as avoiding seasonal toxic algal compounds that can accumulate in mussels.
 

Putting a kelp rope down. (Photo courtesy of Jeff Piercey)

But already, polyculture is showing the way towards higher value from a given site and a more thoughtful, ecologically-oriented approach to aquaculture.

Meanwhile, scientists are working on a wide variety of other projects, such as culturing scallops, clams, and sea urchins. The St. Andrews Biological Station continues to pioneer.
 

Last updated : 2007-11-15

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