SECTION 2: Science that Matters to Canadians

DFO Science is moving to an ecosystem approach to science. A key driver to this approach is the knowledge that fishing and other human activities are having marked effects on the structure of aquatic ecosystems, and in particular, on the most productive ecosystems. The structure of these ecosystems developed over long periods of time, through complex interactions. Intergovernmental bodies concerned with aquatic science and management recognize that scientists must try to quantify the effects of human-driven changes in terms of the complex interactions in ecosystem functioning and to determine whether the effects are reversible, and if so, over what time scales.

In the publication New Ecosystem Science Framework for an Integrated Approach to Management, DFO Science outlines key concepts of ecosystem science and describes the development and adoption of better tools to monitor and study entire ecosystems.

To address federal and departmental priorities and public good needs for the next five years, DFO Science developed a Five-Year Research Agenda, 2007–2012, which focuses on 10 essential research priorities and associated research priority areas. These priorities, which highlight basic and applied research needed for developing new knowledge and improving the use of existing knowledge, are strongly influenced by DFO Science's New Ecosystem Science Framework in Support of Integrated Management. See Five-Year Research Agenda, 2007–2012.

A: TARGETED RESEARCH

The Cascading Effect of the Loss of Top Predators

The collapse of the Atlantic cod fishery and the implications of over-fishing are well known to most Canadians, but the big question remained: “If the cod fisheries have closed, why aren't cod stocks regenerating?”

To gain insight into that question and to understand what happened in the ecosystem of the Eastern Scotian Shelf, Dr. Ken Frank and colleagues at the Bedford Institute of Oceanography analyzed ecosystem data. They discovered that the loss of top predators such as cod, due to over fishing, and the impacts of climate change, have caused a cascading effect throughout the trophic levels of the food chain, influencing the lower levels and causing deep and possibly permanent changes to ocean ecosystems. While it cannot be stated definitively, the results of the study suggest that the ecosystem is operating in a new way, and that fishery closures may not succeed as a strategy for the cod stock's regeneration. The DFO report State of the Eastern Scotian Shelf Ecosystem created a wave of interest on the international scene and led Dr. Frank to publish an article about the work in the journal Science. See the report at: www.dfo-mpo.gc.ca/csas/ csas/status/2003/ESR2003_004_E.pdf

Until recently, most biologists believed that the marine food chain was fixed in a bottomup fashion, and that it was “primary production” of the smallest organisms — phytoplankton — that determines the operation of the system. If primary production were the main governing factor, it would be only a matter of time until the cod fishery bounced back. However, the cod fisheries were closed over a decade ago and there has been no major recovery.

Researchers analyzed 64 different indicators of the ocean's ecosystem, such as sea surface temperature, salinity, contaminants, heavymetal presence, wind patterns, plankton abundance, fish size and condition, and commercial catches, and linked changes across the ecosystem and at different trophic levels, going back to the 1970s. What they proved, for the first time in ocean waters, was a “top-down” cascade of changes driven by fishing and complicated by changing water temperatures.

The decimated cod stock ate fewer shrimp, small crab, herring, sand lance and the like, which became the dominant predators that ate more of the large zooplankton, which in turn declined (zooplankton includes cod eggs and larvae). This intensified predation works against cod recovery. The decrease in zooplankton eased predation on algal phytoplankton, which then increased. Phytoplankton now consumes more of the nitrates in seawater, which have fallen. In short, the changes from heavy commercial fishing cascaded right down to the level of primary production and nutrients.

People in Atlantic Canada's coastal fishing ports who have lived off cod for centuries are adapting, and today take larger than ever catches of valuable crab and shrimp. But Dr. Frank warns that is no guarantee of future abundance. He notes that intensive fishing down the food chain, at a lower trophic level, can be just as dangerous as depleting the top level.

The Eastern Scotian Shelf study also demonstrates why ecosystem-based management systems have been proposed to solve some of the problems inherent in conventional management. His study clearly shows that ecosystems are highly dynamic, and that exploitation is also a driver of change. The analysis points to the need to understand marine ecosystem functioning in order to replace marine exploitation with the sustainable use of marine resources.

DFO Science and University Researchers Collaborate to Study Ecosystem Change, Capelin and Seabirds

The northwest Atlantic is undergoing extensive ecosystem changes associated with both oceanographic conditions and overfishing. Recent research suggests that seabirds have the potential to be quantitative indicators of the status of fish such as capelin (Mallotus villosus) — a key forage fish species in the northwest Atlantic ecosystem, and a primary prey for large predators including cod, seals, whales and seabirds.

DFO researchers Drs. John T. Anderson and Mariano Koen-Alonso, and university professors Drs. Bill Montevecchi, Gail Davoren and Brad de Young, led a collaborative research program with commercial fish harvesters to investigate mechanisms underlying changes to the biology and behaviour of capelin. The program utilized state-of-the-art multibeam technology operated by the Canadian Hydrographic Service, which provided a detailed benthic map of the marine habitat.

Although capelin typically spawn on beaches in waters off the coast of the island of Newfoundland, this research was spatially centered on Funk Island, home of many seabird colonies. The research identified and characterized 11 off-beach capelin spawning sites in nearby inshore waters. A comparison of beach and off-beach sites showed that capelin egg development strategies differed. Integrated results from hydroacoustics and biological sampling suggested that daily vertical movements of capelin and its zooplankton prey are correlated and vary with capelin size. These patterns influenced the daytime feeding schedules of seabirds.

Meanwhile, observations of seabird distributions, surveys of capelin availability, and colony-based measures of seabird diets revealed that seabirds were selective foragers that expanded their foraging ranges when capelin were less available in certain years. Changes in the diets of seabirds, such as the common murre, can be linked to changes in the availability of capelin larger than 100 mm in size, suggesting that seabird diets have the potential to become a quantitative indicator of capelin status. Overall, this type of research framework is important for moving toward ecosystem approaches to fisheries.

Research Behind the Scenes of Snow Crab Stock Assessment

The snow crab fishery is an economically important one restricted to male crabs — but protecting females does not guarantee stock renewal. Overexploiting mature males could result in a lack of mating partners for mature females. The Moncton-based population biology team of Renée Allain and Candy Savoie has been monitoring mating and reproductive performance by observing the quantity of sperm reserves in the females' spermathecae, as well as the total number of fertilized eggs. This is a long and painstaking project requiring huge patience. However, it will develop a better understanding of the dynamics of the snow crab population and the stock condition. For an understanding of the snow crab, it is equal in importance to a biomass estimation by trawl survey.

Snow crab larvae hatch in May in the southern Gulf of St. Lawrence. The planktonic phase lasts approximately 12 to 16 weeks. After the last larval molting (megalopae) it becomes a tiny snow crab and settles on the ocean bottom. The megalopae generally inhabit the area underneath the transition layer between the mixed layer of water at the surface and the deep water layer known as the thermocline. Based on recent study, the snow crab fisheries research team of Michel Biron and Christine Ferron hypothesized that the best larval settlement areas for snow crab may be on the hard-bottomed regions where the thermocline is close to the ocean floor. Their hypothesis is based on results obtained on the sediment type, larval abundance by stage and the abundance and distribution of post-larval crabs. Protecting favourable larval settlement sites may lead to better protection and management of the stock.

By-catch Survival and Conservation

Many commercial fisheries are unable to perfectly target for their desired or regulated species and sizes of fish, and incidentally capture undersized individuals as well as those from other species. The live release of these incidentally captured fish — commonly known as "by-catch" — is often used as a simple conservation measure. In Atlantic Canada, for example, undersized halibut and species at risk, such as spotted wolffish, are released. However, the practice is effective as a conservation measure only if the fish survive on release.

Biologists Hugues Benoit and Tom Hurlbut in DFO's Gulf Region are investigating the potential post-capture survival of fishes released during commercial fishing operation in order to establish effective conservation measures. They are using a combination of data collected by at-sea observers during a large number of actual commercial fishing trips and simulated fishing conditions using a vessel with live-fish holding facilities. Determining survival under conditions relevant to commercial fishing operations is not straightforward and therefore, to date, has been done for a limited number of species and to varying degrees of accuracy.

Factors affecting the likelihood of survival of by-catch include: environmental ones, such as water and air temperatures; those related to the fishing operations themselves, such as the gear used and how long fish remain out of water; plus differences in resilience between species. The study results will allow researchers to better determine the conditions under which post-capture release is a viable option and those where avoiding the by-catch is the only conservation option toward minimizing fishing-induced mortality.

Research Mission in the Sargasso Sea

In March and April 2007, DFO researcher Martin Castonguay of the Maurice Lamontagne Institute participated in an international mission in the Sargasso Sea on the breeding biology of eels. Spearheaded by Denmark, the mission brought together scientists from five countries. It involved two vessels, a Danish oceanographic vessel, and a Canadian commercial trawler on which Martin Castonguay, mission head, was aboard. DFO provided a financial contribution in the form of a grant under the International Governance Agenda.

The mission achieved its main objective: to collect eel larvae samples in order to shed light on fundamental questions relating to the population genetics of the American eel and European eel. However, due to a variety of technical difficulties, researchers were unable to achieve the objective of capturing adults on the spawning site. A workshop was held in August 2007 in Copenhagen to discuss the focus of the scientific articles that will result from the research program.

Integrated Multi-Trophic Aquaculture in the Bay of Fundy: Continuing to Evolve

Developing new techniques for the evolution of aquaculture-based seafood is the goal of the Integrated Multi-Trophic Aquaculture (IMTA) program at the St. Andrews Biological Station and the University of New Brunswick in Saint John.

Under the leadership of Drs. Shawn Robinson (DFO) and Thierry Chopin (UNBSJ), the program promotes the practice of recycling waste by-products from one species to become inputs, such as fertilizers and food, for another. In this way, the entire operation becomes more socially acceptable, economically profitable and environmentally benign. The concept of a balanced system combines fed fish species, such as salmon, with natural biofilters like mussels and seaweeds on a single farm site, so that fewer of the nutrients originating from the highenergy fish food are wasted. The seaweed extracts inorganic byproducts like nitrogen and phosphorous out of the water, and the mussels thrive in an environment enriched with concentrations of food and waste particles. The research has been ongoing in the Bay of Fundy with the salmon industry for six years.

Seaweed such as kelp, and shellfish such as mussels are key components of the project, as are equipment development and harvesting techniques. Economics and marketing — keys to the industrial success of the project — are being directed by Dr. Neil Ridler (UNBSJ) in close collaboration with Cooke Aquaculture. Water flow dynamics through the IMTA sites are being studied by Dr. Fred Page of DFO, while the general health of the sites is being monitored by Dr. Les Burridge, also of DFO. Gregor Reid, a postdoctoral researcher on the project, has developed computer models to evaluate the amount of nutrient recovery from the IMTA system.

It would appear that by adding kelp to the sites, it is possible to recapture up to 40 percent of the nutrients available during its growing season, while mussels can recapture up to 50 percent of the fine particulates released from the salmon cages. This extra food and energy these species receive results in growth rates about 50 percent faster than normal. Additional species are also being investigated.

In the next five years, the program will be supported by the Atlantic Innovation Fund of the Atlantic Canada Opportunities Agency, along with industrial partners Cooke Aquaculture Inc. and Acadian Seaplants Limited, and governmental partners Environment Canada (EC), the Canadian Food Inspection Agency (CFIA), and the New Brunswick Department of Agriculture and Aquaculture (NBDAA). The team is working to promote and advance the IMTA concept across Canada and beyond with research partners such as the Pacific SEA-Lab Research Society.

Atomic Bomb Radiocarbon Shows Beluga Whales Live Twice as Long as Previously Believed

In disproving the old assumption that beluga had semi-annual growth layers in teeth, a DFO research team, led by Dr. Rob Stewart of the Freshwater Institute, proved that the whales live twice as long as previously believed — altering our understanding of beluga population dynamics. The researchers validated the ages of beluga based on datespecific incorporation of atomic bomb radiocarbon into tooth growth layer groups (GLGs). The research confirmed that GLGs form annually in beluga and provide an accurate indicator of age up to at least 60 years old. Radiocarbon assays of dentinal layers formed in belugas harvested between 1895 and 2001 indicated that radiocarbon from atmospheric testing of nuclear weapons was incorporated into growing teeth and retained for the rest of the animal's life.

The team included Steve Campana, Cynthia Jones and Barbara Stewart. Learn more in the December 2006 issue of the Canadian Journal of Zoology at: http://article.pubs.nrc-cnrc.gc.ca/RPAS/rpv?hm=HInit&journal=cjz&volume=84&afpf=z06-182.pdf

Aquatic Biotechnology Research and Development Program

Fisheries and Oceans Canada is linking innovative biotechnology and genomics science with higher-level policy making and on-the-ground fishery and aquatic ecosystem management decisions through its Aquatic Biotechnology R&D Program. There are four research themes in the DFO Aquatic Biotechnology & Genomics R&D Strategy: Biotechnology and Aquatic Resource Profiling, Biotechnology and Aquatic Animal Health, Biotechnology and Aquatic Ecosystem Health, and Regulatory Science for Aquatic Animals with Novel Traits. Read more about the strategy online at: www.dfo-mpo. gc.ca/biotech/docs/abgrds_e.htm

A prominent example of research conducted under the theme of Regulatory Science for Aquatic Animals with Novel Traits is the recently published study looking at the interaction between the genetic make-up of fish and the environment in which the fish were raised. DFO has conducted research to investigate questions about genetically engineered (GE) fish from a regulatory point of view, and this continuing research is taking place in closed, biocontained facilities.

DFO researcher Dr. Robert Devlin and his team, Drs. Fred Sundström, Mare Lõhmus and Wendy Tymchuk, compared the effect of rearing GE and non-GE salmon in contained semi-naturalized streams and under hatchery conditions. The GE salmon showed decreased growth in the semi-naturalized streams when compared with those raised in hatchery conditions, while wild-type fish were much less affected by the rearing environment.

Research showed that GE salmon from hatchery environments, when put into contained semi-naturalized streams, have a greater impact on prey than non-GE salmon. However, it was also found that the rearing environment can have a strong effect on predatory behaviour: genetically engineered fish reared in semi-naturalized streams were not only smaller, but were also not as predatory as hatchery-reared GE fish of the same size or age.

Dr. Devlin and his team also looked at the predation behaviour of GE-fish that were reared in hatchery conditions but not fed unlimited amounts of food. These fish were fed a restricted ration (that is, an amount of food that was the same as that desired by wild-type hatchery-raised salmon) and didn't grow as large as the GE-salmon that had unlimited food. Surprisingly, when these fish were examined for their predation behaviour in the semi-naturalized stream, the restricteddiet GE fish consumed more prey than either the wild-type or the unrestricted-diet GEsalmon. When this result is compared to the reduced predation that was seen in the GEsalmon reared in the semi-naturalized streams, it is clear that predatory effects are not just determined by the size of the fish or that the fish is transgenic — it is likely a combination of how the fish were reared and their genetic make-up.

The results from this study demonstrate that the rearing environment can dramatically change how fish behave in that environment as well as how fish grow and develop. This “uncertainty” can lead to either an underestimate or an overestimate of risk. This research is particularly important to regulators as it suggests that results from experiments using GE fish reared or studied under hatchery conditions may not be applicable to how a given fish type may behave or grow in the wild. An English-language article describing this topic more fully is found online in the journal for the Proceedings of the National Academy of Sciences of the United States of America (PNAS) at: www.pnas.org/cgi/ content/abstract/104/10/3889

Marine Studies of Pacific Salmon

Canada maintains two research programs on factors that regulate the early marine survival of Pacific salmon. These studies are essential for separating the effects of fishing and freshwater habitat change on salmon production from natural variations in oceancarrying capacity. Furthermore, Canada's Salmonid Enhancement Program (SEP) annually releases over 300 million Pacific salmon in coastal waters. Understanding how SEP-produced salmon interact with the wild Pacific salmon and affect the ocean-carrying capacity for Pacific salmon are important questions for effective conservation and provision of sustainable fisheries.

Strait of Georgia Study

Juvenile salmon surveys have been conducted in the Strait of Georgia during July and August for the past 10 years. Information collected during these surveys includes fish length, distribution and diet of juvenile Pacific salmon and other non-salmonid species, and information on the early marine survival of juvenile salmon in the region. This information is being used to assess the impact of changes in the ocean climate on Pacific salmon. Recent research has been focused on understanding the decreasing marine survival of coho salmon in the Strait of Georgia.

The percentage of Canadian hatchery coho salmon in the Strait of Georgia increased from almost zero in the early 1970s to an average of 70 percent in the late 1990s, but between 2000 and 2006 the percentage declined to only 30 percent. The recent decline may result from several factors: an overall reduction in the number of hatchery coho released to the Strait during the year, and the continued release of hatchery coho during May, which unfortunately coincided with an earlier-thanusual May "spring bloom" of prey production in the Strait of Georgia. Adding to the story, there has been a recent increase in abundance of wild coho salmon in the Strait that has not yet been explained. Research has shown that hatchery and wild coho salmon differ in their response to early marine conditions, but more adequate explanations are needed. Those explanations are among the objectives of a new initiative studying the broader ecosystem in the Strait of Georgia.

High Seas Pacific Salmon Program

Under this program, DFO has been collecting oceanographic data, juvenile salmon and associated species along the West coast of British Columbia and Alaska since 1998 to assess the effects of ocean conditions and climate change on the distribution, migration, growth rate and survival of Pacific salmon. These surveys are normally conducted during spring/summer, fall and winter over two- to four-week periods. One of the more unexpected findings has been the link between salmon growth and the quality of the food they prey upon. Even small changes in prey quality have been seen to have a large effect on the growth trajectory and ultimate survival of juvenile coho salmon.

The program also has strong international linkages. Salmon and ocean systems do not respect political boundaries. The High Seas team collaborates with similar research programs in the United States to develop an integrated picture of salmon behaviour and the conditions that affect their survival. Their research is also relevant to the work of the North Pacific Anadromous Fish Commission, which brings together scientists from Japan, Russia, the United States, Korea and Canada to share resources and results related to fisheries research.