Environmental Research at the St. Andrews Biological Station : DFO, Maritimes Region

The Environmental Sciences Section (ESS) is one of four Sections in the Marine Environmental Sciences Division in the Maritimes Region and is based at the St. Andrews Biological Station. Within ESS there are five research programs that are concerned with the sustainability of both harvest and cultured fisheries resources and habitat. Specifically the programs focus on: the effects of changes in the coastal and marine environments of wild Atlantic salmon; the effects of mariculture practices on the coastal zone environment; the occurrence and effects of harmful algal blooms; the hazards and risks of organic chemicals and the environment; and the biochemical and physiological effect of organic chemicals on aquatic animals.

For more information:

Dr. Kats Haya
531 Brandy Cove Road
St. Andrews, NB E5B 2L9
Tel: 506-529-8854; Fax: 506-529-5862

The coastal zone stretches from the highest point on the shore reached by tides to the edge of the continental slope (where depths are 200m) and extends to the tidal limit of estuaries. Therefore, the area of concern is very large. The coastal zone is also the most used part of the marine environment by man and the site where resource conflicts are expected. The long-term aim of the benthic ecology program is to understand the factors that influence benthic production and to apply this knowledge to current problems of coastal zone resource management.

Excess feed and feces (organic wastes) from finfish aquaculture operations accumulate in the sediment. Microbial action on these wastes rapidly depletes oxygen and results in a negative impact on the benthic habitat directly under the cage. A build-up of organic wastes may also affect respiration and productivity in the water column distant from the cage site. Recent research by Dr. Wildish focused on such ecological effects of salmonid aquaculture in the Bay of Fundy. As a result of his studies, Dr. Wildish was able to develop and implement a new monitoring strategy based on geochemical measures (sulphide content and redox potentials).

Two methods of using acoustic multi-beam mapping techniques to visualize sediment characteristics.

The geochemical measures provide quantitative data on the degree of organic impact at each site. Ongoing studies are determining the rate at which build up of wastes occur at new sites and the changes that occur when a site is abandoned during fallowing practices. The New Brunswick Department of Agriculture Fisheries and Aquaculture has adopted this monitoring method to aid in their management of the aquaculture sites, for example, determining maximum holding capacity or to recommend moving the cage to minimize impact on the sediment.

A novel way of determining organic enrichment has been devised based on sediment profile photography and Hargrave prism corers. These plexiglass corers are placed in sediments by SCUBA divers and then brought to the surface with a sediment profile of up to 30 cm for photography, sub-sampling, and interpretation. The latter is based on the redox discontinuity depth, organisms, burrows, and voids present/absent as revealed in the digital photographs. The result is an integrated number referable to the organic enrichment index. Dr. Wildish has validated this method, called sediment profile imaging (SPI), in the Bay of Fundy salmon culture industry and it is planned to field test the method in the same industry in Tasmania, Australia.

Dr. Wildish´s group has also begun collaborating with Dr. John Hughes-Clarke of University of New Brunswick, in using sidescan sonar backscatter signals (acoustic imaging) to map the extent of organic enrichment events near salmon cages. They have set-up a Trackpoint based system, called GAPS (grab acoustic positioning system), with the technical help of David McKeown, of Bedford Institute of Oceanography, which can take grab samples at known locations on the seabed. Precise grab sampling is needed to validate the acoustic interpretations.

Atlantic salmon stocks in rivers of the inner Bay of Fundy have crashed in the past decade, believed to be the result of abnormally low survival of salmon during their oceanic phase. In 2001, these stocks were declared "endangered" under the new Canadian Species at Risk Act. This same year, a major marine research effort called the Atlantic Salmon Marine Acoustic-tracking Project, Salar MAP, was launched to study the survival of salmon that originate from rivers around the Bay of Fundy after they enter the marine environment. The objective is to determine the location, timing and potential causes of salmon disappearance at sea.

Dr. Gilles Lacroix leads the project in cooperation with many supporting partners, including the Atlantic Salmon Federation. The project proponents have developed new technology and methodology to track young salmon (called smolts and post-smolts) through marine coastal areas and beyond, and to capture these alive for examination and release.

One initiative is a large-scale project to track and compare the migration of these salmon during their first summer and autumn at sea. The SALAR, a small craft outfitted with the latest in acoustic telemetry equipment for tracking tagged salmon in the Bay of Fundy, was launched in 2001. For the first time, migrating wild salmon smolts, captured at the mouth of rivers, were tagged by implanting coded acoustic tags known as pingers, in their abdomen and releasing them after several hours of recovery. The tagged wild smolts were released from five Bay of Fundy rivers. Lines of listening posts (an acoustic receiver attached to a mooring station), akin to toll gates across the Bay of Fundy, were used to monitor the pingers and record the time and location of smolt passage. Several hundred automated acoustic receivers were deployed to monitor the passage of tagged salmon from the rivers, through the coastal zone, inner and outer Bay of Fundy, and into the Gulf of Maine from May to October. The project is the first in Canada to use whale-safe gear on the listening posts to prevent whale entanglement. The objective is to identify the distribution and migration routes for salmon in relation to environmental conditions. It will clarify our understanding of the first summer of marine life for salmon and provide much needed answers to questions about the habitat used by post-smolts from rivers of the inner Bay of Fundy. To date, Salar MAP has achieved a significant breakthrough in our ability to conduct research on salmon at sea. The project is the first to track small fish such as wild smolts and post-smolts from fresh to salt water over an expanse as large as the Bay of Fundy for a full season in the marine life of salmon.

Simultaneously, surveys aboard the Fisheries and Oceans Canada research vessel, CCGS Alfred Needler, use new methods to capture live salmon for examination as they leave the Bay of Fundy. The aim is to identify where endangered salmon stocks go after they leave the rivers and to assess their health. For the first time in almost three decades, exploratory fishing resulted in the capture of live salmon post-smolts in the Bay of Fundy for examination. The CCGS Alfred Needler was equipped with prototype trawling gear designed by Salar MAP to capture salmon alive with minimal impact. After examination, post-smolts were returned to the water alive. External marks and scales were used to identify if post-smolts captured at large in the Bay of Fundy were wild or of hatchery or aquaculture origin. A health report card for each group of fish was produced for comparison between stocks and over time. This includes ratings for condition, growth, parasites and diseases. By conducting these surveys annually, the success of the recovery strategy undertaken for inner Bay of Fundy salmon will be assessed.

Marine phytoplankton, including some that produce toxins, can reach undesirable concentrations during annual blooms. These harmful algal blooms (HABs) may have an adverse effect on wild and cultured fisheries resources. The HAB program is under the leadership of Ms. Jennifer Martin. The objectives are to:

Magnified cells of the phytoplankton species in the Bay of Fundy that produce the biotoxins associated with paralytic shellfish poisoning (a) and amnesic shellfish poisoning (b).

This program has provided a better understanding of algal bloom dynamics, especially those that can cause harm to fisheries and human health.

The Bay of Fundy has a long history of shellfish accumulating paralytic shellfish poisoning (PSP) toxins annually following blooms of Alexandrium fundyense, a phytoplankton species known to produce the toxins. During 1976 and 1979, there were hundreds of tonnes of herring mortalities due to PSP toxins that were accumulated through the food chain. Domoic acid, the toxin in amnesic shellfish poisoning, has also been detected in shellfish in the Bay of Fundy. Although the species that produces domoic acid in the Bay of Fundy, Pseudo-nitzschia pseudodelicatissima, is present year round, concentrations exceeded one million cells per litre and resulted in unsafe levels of domoic acid in shellfish only in 1988 and 1995. In addition, several other harmful species that have been responsible for problems elsewhere in the world have been observed in Bay of Fundy and adjacent waters.

A study of the occurrence and dynamics of phytoplankton populations from 4 locations in the south west Bay of Fundy was initiated in 1987 and continues today. In this study, all phytoplankton greater than 5 µm in size are identified and enumerated. Also, environmental and chemical parameters are measured in order to try to identify factors that control HABs. The knowledge gained from these studies was instrumental in identifying and assessing the future risk to finfish aquaculture from a bloom of Mesodinum rubrum that caused fish kills in Passamaquoddy Bay in the late 1990´s. The production of a phytoplankton identification key for the Bay of Fundy area is in progress.

Collaborative studies with Drs. Kats Haya and Shawn Robinson (Aquaculture Division) have indicated that the year-round presence of PSP toxins in scallops is due to incomplete depuration before the accumulation of more toxin as a result of annual blooms of Alexandrium fundyense. On the other hand, mussels accumulate PSP toxins but can readily depurate PSP toxins within two months.

Ballast water taken on by vessels for stability has also been identified as an important vector for the transfer of harmful algal species worldwide. Ms Martin has initiated a program to provide scientific background and support for improving Canadian guidelines for offshore ballast water exchange. Such studies will help to assess the risk from the introduction of non-indigenous species through ballast water exchange operations.

The objectives of the environmental chemistry and toxicological research program of Drs. Kats Haya and Les Burridge are:

Harmful effects (toxicity) of a compound depend not only on its chemical properties but also on how much the animal is exposed to and for how long. Exposure to a sublethal concentration of a chemical can impair an organism´s ability to maintain a healthy physiological state and can cause changes in behavioral, physiological, and biochemical processes. A goal of this program is to investigate such responses and to develop a series of diagnostic tests to assess the health of aquatic communities and populations. Identification of conditions for optimum health is critical, for example, in maximizing the growth rate and economic return for cultured fish. The well-being of invertebrate populations is essential to the good health of the near-shore ecosystem. Current studies focus on the environmental impact of chemical wastes produced by the salmon aquaculture industry and the effect of chemicals that affect normal hormonal function on the growth and survival of wild juvenile salmon during their seaward migration.

Salmon aquaculture is an important renewable resource industry in both the Pacific and Atlantic coasts of Canada. In a relatively small marine area in southwest New Brunswick and Maine, the industry has developed rapidly from a few farms in 1982 to over 100 salmon culture sites in 2000. The salmon aquaculture industry is an anthropogenic source of organic and chemical wastes. Organic wastes result from excess feed and faeces that may accumulate in the sediment and lead to eutrophication in the water column and anaerobic conditions in the sediment. Poor water quality and crowded conditions induce stress in caged fish and contribute to impaired growth and predispose them to disease. This necessitates the use of chemical therapeutants to combat sea lice infestations and disinfectants help to prevent the spread of the virus, Infectious Salmon Anaemia.

This project takes an integrated and multi-disciplinary approach to assessing the impacts on the ecosystem of chemicals used in the salmon aquaculture industry both in the Pacific and Atlantic coastal regions of Canada. The objectives are: to identify chemicals, their sources, and the quantities released; their distribution, environmental fate and concentrations; and their effect on the ecosystem and important harvest fisheries resources. In addition, it is hoped that potential conflicts with other users may be addressed to provide a basis for improved protection of cultured and wild fisheries resources and their habitat.

Recently, chemicals have been used to combat sea lice infestations that have plagued the salmonid aquaculture industry in New Brunswick. The lethality of these chemicals to aquatic "non-target" animals, particularly crustaceans such as lobster and shrimp was determined. One treatment, Ivermectin (used as an anti-parasitic additive in fish food) was found to be lethal to shrimp, but only if the shrimp ate the food. Pyrethrins, a pesticide administered by bathing the salmon in a sea water solution of it, was less toxic to Stage I lobster larvae than the other three larvae stages. In a collaborative study with Ms. Susan Waddy (Aquaculture Division), lobsters were found to be tolerant to a single exposure for 60 minutes to azamethiphos, an organophosphate pesticide, at concentrations expected in the environment. The same lobsters became increasingly sensitive on subsequent exposures spaced two weeks apart. In addition, azamethiphos was found to affect spawning and impair reproduction of female lobsters. Laboratory studies indicate that another in-feed preparation, emamectin benzoate, has effects on the growth of lobsters.

Results of collaborative studies with BIO scientists indicated that the profile of heavy metals and persistent organic chemicals in the sediment near cage sites were different than in sediment further from the site. For example, copper, zinc, organic carbon and polychlorinated biphenyls (PCBs) concentrations were higher in sediment near the salmon sites than in sediment sampled further from the cage site. The sources of the chemicals in the sediment were probably from the fish oils and other natural ingredients used in the production of fish feed. Other effects observed are impacts on the biodiversity of macrofauna and the presence antibiotic resistant bacteria in sediments near salmon aquaculture sites.

Decreased growth is a common response in fish exposed to sublethal concentrations of chemicals. Research has focused on the study of biochemical mechanisms involved in the utilization of the energy derived from food. Exposure of juvenile Atlantic salmon to pesticides or conditions of low pH resulted in decreased growth. Various biochemical measurements suggest that energy was utilized to combat the effects of the exposure to the detriment of growth. Other studies have shown that chemicals can disrupt smoltification, the physiological process which culminates in salmon successfully surviving the change from life in freshwater streams to life in the ocean. A preliminary study indicated that nonylphenol, a chemical that may interfere with sex hormone functions, may interfere with smoltification, growth and survival at sea. A collaborative field and laboratory study with scientists from universities, the Department of the Environment and DFO to study this effect of nonylphenol is in progress.

Environmental Research at the ST. ANDREWS BIOLOGICAL STATION

Environmental Research at the
ST. ANDREWS BIOLOGICAL STATION