Species at Risk Research at BIO - Kirsten Querbach, Patrick O'Reilly, Peter Amiro, Jamie Gibson, Rod Bradford, Jim McMillan, and Arran McPherson

The Maritime Aquatic Species at Risk Office (MASARO) co-ordinates the regional strategy for protecting and recovering species at risk for Fisheries and Oceans Canada. In 2002, MASARO assisted in coordinating a number of initiatives, including species at risk research efforts. Research programs at the Bedford Institute of Oceanography have focused on inner Bay of Fundy Atlantic salmon (endangered), Atlantic whitefish (endangered), Lake Utopia dwarf smelt (threatened), and the leatherback turtle (endangered). The species at risk research conducted within the Diadromous and Marine Fish divisions during the past year has been undertaken with the direction of multi-stakeholder recovery teams and/or internal DFO review teams to ensure specific needs of each species are being addressed.

Inner Bay of Fundy (iBoF) Atlantic Salmon

Wild anadromous iBoF Atlantic salmon have declined by 90% or more since 1989. Juvenile salmon have not been detected recently in nearly one-half of the rivers in which they previously occurred. One research initiative has focused on estimating total population size and survival rates. Survival from smolt to adult is being assessed using mark-recapture studies of both seaward migrating salmon smolts and adults that returned to freshwater to spawn. Within the freshwater environment, models are being developed to estimate total juvenile abundance within a river from electrofishing data. At the smallest spatial scale, electrofishing catchability is modelled and used to make inferences about population density within an electrofishing site. These densities can be modelled as a function of habitat type, which is categorized using remote sensing and a geographic information system (GIS). At the largest spatial scale, population size is estimated for a watershed from the electrofishing data and the distribution of habitat types within the watershed. The results of these analyses will be used to document the decline, status, and recovery of Atlantic salmon in inner Bay of Fundy rivers, identify critical habitat within freshwater, and aid in the development of strategies for their recovery.

Rotary screw trap used to live-capture Atlantic salmon smolts in the Big Salmon River, N.B. - photo by Ross Jones.

A growing body of evidence suggests that the sharp decline of iBoF salmon is due to low marine survival resulting from unknown causes. To prevent the imminent extinction of this assemblage of populations, the recovery team has protected remnant populations in captivity until causes of mortality can be identified and mitigated. Maintenance of small populations in captivity can be complicated and problematic. Inbreeding and loss of genetic variation are concerns for the long-term health of these captive populations and are a result of: (1) the limited pool of founders (many of which may be related), (2) the high reproductive potential of this species, and (3) the expected absence of migration (geneflow) to these populations in the future. Furthermore, exposure to captive conditions may bring about physiological, behavioural, and genetic changes that are thought to decrease the wild fitness of salmon upon their return to their native river habitat.

Many of these concerns have been addressed by incorporating a broodstock management program that includes both captive and wild components. First, remaining iBoF salmon are DNA fingerprinted, and placed into population-specific pedigrees. This pedigree is then consulted to carry out a mating scheme that simultaneously minimizes co-ancestry, inbreeding, between family domestication selection, and mal-adaptive change due to small population sizes, and random genetic drift. Most of the progeny resulting from such crosses are released into the wild, where they are subject to natural selection. A small portion from each family is also being retained in captivity. When it is time to produce the next generation of genebank salmon, juveniles about to go to sea will be recovered from the wild, DNA fingerprinted, pedigreed, and captive-reared to adults. When the original founding families are not present in these wild-exposed samples, representatives from these missing families will be taken from the captive population of genebank salmon. Use of a genetically-sound broodstock management program, and a strategy that involves river-exposure of juvenile salmon, will increase the wild-fitness of salmon and hence, the likelihood of success of future attempts to restore self-sustaining runs of anadromous Atlantic salmon to the inner Bay of Fundy.

Atlantic Whitefish

The endangered Atlantic whitefish is endemic to Nova Scotia and has historically been found in only two river systems. A suite of factors, including over-fishing, river acidification, inadequate fish passage, and the introduction of exotic fish species is thought to have contributed to the loss of all anadromous runs of this species. Consequently, the potential for re-establishment of Atlantic whitefish populations has been the focus of the recovery program. Research to date has included: (1) assessment of habitat quality in candidate lakes for re-introduction, (2) assessment of habitat requirements for natural life-cycle closure, and (3) development of a captive breeding program to support physiological research and the anticipated re-establishment program. Investigated metrics of habitat suitability have included the extent of acidification and species composition/abundance of both benthic macroinvertebrates and stream/lake fish assemblages. The captive breeding program has yielded three age classes of fish which can now be used to assess the tolerance of Atlantic whitefish to water quality variables. Release strategies expected to improve the likelihood of establishing self-sustaining populations will be developed from this information.

Atlantic whitefish - photo by Bob Semple.

Lake Utopia Dwarf Smelt

Lake Utopia, New Brunswick is one of several oligotrophic lakes in eastern Canada where at least two forms of smelt occur in sympatry; the traditional smelt and the dwarf form, the latter of which was designated as 'threatened' in 1998. Threats to population viability include: (1) perceived low spawner abundance, (2) restricted spawning, (3) adult capture in a recreational dipnet fishery, and (4) potentially high predation as a consequence of fish stocking programs. In collaboration with province of New Brunswick biologists and colleagues at the University of New Brunswick, research has focused on accumulating information on spawner abundance, spawning distribution, habitat requirements, and the appropriateness of the stated threats to dwarf smelt. Initial results suggest that spawner abundance may be in the tens of thousands and therefore greater than previously thought. Further assessment of genetic structuring, development of reliable criteria for morphological identification, and systematic surveys of smelt spawning activity are underway.

Leatherback Turtle

Staff of the Bedford Institute of Oceanography have partnered with Dalhousie University since 2000 to study leatherback turtles using satellite-linked timed-data recorders (SLTDRs). This project has tracked leatherback turtles to gain information about migration and feeding (diving and foraging) behaviour. Dalhousie researchers and fisher members of the Nova Scotia Leatherback Turtle Working Group, led by Dalhousie University student Mike James, have been able to live-capture free-swimming leatherback turtles and attach the SLTDRs using a harness fitted to the animal.

A leatherback turtle - photo of the Nova Scotia Leatherback Turtle Working Group.

Preliminary results from this work have revealed coastal and offshore foraging movements (characterized by shallow dives of short duration) in Canadian and USA waters, with extensive feeding in slope waters east of the Fundian Channel and Georges Bank. Time spent in Canadian waters has varied considerably; some animals depart soon after tagging while others remain foraging in Canadian waters for three to four months. Tagged leatherback turtles have migrated to Caribbean waters adjacent to nesting sites, to pelagic waters at low latitude, and to shelf waters off the southeastern United States. Data collected through this research will assist in evaluating the vulnerability of this species to human activities occurring in Canadian waters and throughout its North Atlantic range.

Future

With the Species at Risk Act scheduled for proclamation in 2003, MASARO is creating a regional species-at-risk website to be launched shortly thereafter. This website will house information on recovery planning and provide updates on recovery-related research projects, like the ones described here.