CCFFR-99 POSTER SESSION
Posters can be viewed and discussed between the afternoon of Friday 8 January and the afternoon of Sunday 10 January.

Barber, F. and S. Yuen. Department of Fisheries and Oceans, Ottawa K1A 0E6

IN PINK SALMON A DECLINE IN AN EVEN-YEAR WEIGHT AND IN SIZE-SELECTIVE CANNIBALISM BY ADULT ON YOUNG ARE ASSOCIATED WITH FRASER RIVER SOCKEYE DIVERSION(P)

Catch statistics on mean weight again demonstrate that cannibalism in pink salmon is selective for larger size. A conceptual model (Barber and Yuen 1994, 1995, 1997) which associates a number of trends, ie in coastal salinity, coho weight and surviva l, both Fraser River sockeye (FRS) prespawning mortality and diversion, and Fraser River pink salmon (FRPS) weight, ie an odd-year weight, is extended to include declines in an even-year weight of pink salmon and in size-selective cannibalism by adult on young; both appear inversely associated with an increase in FRS diversion. And just as the decline in FRPS weight was suggested a density-dependent effect (DDE) due to this increased diversion, so the decline seen in at least one even-year weight series may also be a DDE; curiously however the decline in this weight appears less overall than the decline in FRPS weight. In particular the recent large annual FRS diversions appear associated with an absence of trend in recent even-year weights; we infer th at size -selective cannibalism, ie selection for larger young, also varies inversely with diversion: a change in behaviour of adult pink salmon associated with increased FRS diversion, eg earlier schooling and decreased feeding, means less cannibalism an d so decreased selection for larger young.

Challen, L. and R. Mackereth. Faculty of Biology and Centre for Northern Forest Ecosystem Research, Lakehead University, Thunder Bay

ON STREAM BENTHIC MACROINVERTEBRATE POPULATION RESPONSE TO LOGGING ROAD CROSSINGS IN NORTHWESTERN ONTARIO (P)

Stream macroinvertebrate community's dominance, density, species composition and diversity are known to be effected by forest management practices. Thus, stream macroinvertebrate characteristics may be useful indicators when monitoring alterations to fish habitat. This study looked for reliable trends in the response of stream macroinvertebrate communities to Northwestern Ontario logging road crossings. Benthic macroinvertebrate samples were taken upstream and downstream from fifteen road crossings. Stream discharge and substratum size measurements were also collected at these locations. Upstream and downstream invertebrate population parameters were compared. Preliminary analysis showed differences in population characteristic between upstream a nd downstream samples at some road crossings. Variation in population response existed between study sites. Further analysis will test the hypothesis that substrate size and water velocity mediate benthic populations response to disturbance.

Corrigan, Sean and A. Curry. NBCFWRU, Department of Biology, University of New Brunswick, Fredericton, N.B. Rockweed@nb.sympatico.ca

FISH COMMUNITIES IN ROCKWEED IN THE BAY OF FUNDY (P)

The commercial harvesting of Ascophyllum nodosum (rockweed) potentially alters the intertidal architecture influencing fish populations inhabiting the rockweed. The impact on these fish communities cannot be assessed until an inventory of species and a description of their microhabitat use have been compiled. I have surveyed unharvested sites near the mouth of the Bay of Fundy over the course of a year. Traps and nets were deployed in the intertidal zone and fish caught were identified and aged. By means of stomach content analyses, diet choice was described and compared to seasonal prey availability data from the Department of Fisheries and Oceans. I also analyzed underwater video images to quantify the spatial and temporal use of the rockweed be ds by fishes. To date, 12 separate species of fish from varying age classes have been noted. Results will provide a critical guideline for assessing the sustainability of rockweed harvesting in the Bay of Fundy.

Degner,S. and C.Hawryshyn. Department of Biology, University of Victoria, Victoria, British Columbia

POLARISED LIGHT DISCRIMINATION BY RAINBOW TROUT (P)

Salmonids have been shown to be polarisation sensitive through behavioural and electrophysiological experiments. While salmonids behaviourally orient to polarised light fields, it is not yet known whether they can discriminate different planes of pola rised light. This could potentially enhance photocontrast, enabling salmonids to better perform tasks such as visual recognition. Since plankton as well as the scales of fish reflect a pattern of polarised light, salmonids may use this pattern to differen tiate between predators and prey. For instance, the same fish could appear drastically different to a polarisation sensitive observer when it reflected horizontally polarised light compared to when it reflected vertically polarised light. In order to det ermine if rainbow trout can discriminate planes of polarised light, young rainbow trout will be trained to a vertical e-vector using an operant paradigm with food pellets as a reward. Once trained, the fish will be presented with a contrasting e-vector ad jacent to the trained vertical e-vector. (Funded by NSERC)

Forster, M. and W.G. Franzin. Department of Fisheries and Oceans, Winnipeg, Manitoba.

AN ANALYSIS OF THE EFFECTS OF AGRICULTURAL LANDUSE PRACTICES ON PRAIRIE STREAMS AT DIFFERING SPATIAL AND TEMPORAL SCALES (P)

The effects of local agricultural practices on stream habitat and stream biota are being studied via a comparative analysis of nine different catchments in southwestern Manitoba. Stream analyses, riparian zone assessments, and quantification of local landuse practices are being conducted at different spatial and temporal scales. The nine sites are representative of three different catchment sizes : from 20-30 square kilometres, from 60-70 square kilometres, and from 250-300 square kilometres. Six of t he study sites are located on streams flowing through areas dominated by agricultural activity. Three of the study sites are located on streams virtually undisturbed by human development. Sampling and analysis are being done seasonally, and will be examin ed against regional historical data. This study is intended to determine the presence or absence of agricultural contaminants in stream environments in relation to local landuse practices. An additional component of the study is to examine the role of the riparian zone in the transport of these substances. The catchments will be assessed in terms of the quality and availability of aquatic habitat, species diversity, stream productivity, and riparian zone integrity.

Galloway, B.J. and J.D. Kieffer. Department of Biology and Centre for Coastal Studies, University of New Brunswick, Saint John, New Brunswick.

THE INFLUENCE OF TEMPERATURE ON THE PHYSIOLOGICAL DISTURBANCE ASSOCIATED WITH EXHAUSTIVE EXERCISE IN JUVENILE ATLANTIC SALMON (SALMO SALAR) (P).

In this study, we investigated the effects temperature on the post-exercise recovery process in juvenile Atlantic salmon. To test these effects, we measured the metabolic fuels (e.g., Phosphocreatine, ATP) in the white muscle, and the muscle [lactate ], plasma [lactate], and plasma osmolarity during rest, exhaustion, and 0, 1, 2, and 4 hr of recovery from exhaustive exercise in (I) fish fully acclimated to either 12 or 18 C, or in (II) fish exercised at 12 C and acutely exposed to 6 and 18 C during re covery. Preliminary results indicate similar recovery patterns of muscle and blood metabolites in fish fully acclimated to either 12 or 18 C. In contrast, however, the patterns of recovery were markedly influenced when fish were exercised at 12 C and al lowed to recover at either 6 or 18 C. For example, muscle phosphocreatine and ATP levels decreased following exhaustive exercise, however, recovery was delayed considerably in fish exposed to 6 C during recovery. Muscle lactate levels increased immediate ly following exhaustive exercise in all fish, but the concentrations remained elevated throughout the 4 hr recovery period in fish exposed to 6 C. Fish acutely exposed to 18 C during the recovery period had cleared all their muscle lactate by 4 hrs. Rec overy of both plasma lactate and osmolarity showed similar patterns to that of muscle lactate. Overall, our preliminary results indicate that acute temperature shifts can markedly influence the recovery patterns in fish following exhaustive exercise. Ad ditional experiments will be conducted to determine how acute temperature changes influence gas exchange and ammonia excretion patterns in fish following exhaustive exercise.

MacIntosh, K. and R. Mackereth. Department of Biology, Lakehead, University, and Centre for Northern Forest Ecosystem Research, Thunder Bay, ON.

MOVEMENT BY BROOK CHARR, RAINBOW TROUT AND COHO SALMON INTHREE TRIBUTARIES OF NIPIGON BAY, LAKE SUPERIOR (P)

Tributary streams of Lake Superior are known to be important habitat for salmonid species and this habitat is potentially threatened by timber harvesting. Three small tributaries of Nipigon Bay, Lake Superior, were chosen to study the movement patter ns of brook charr (Salvelinus fontinalis), rainbow trout (Oncorhynchus mykiss) and coho salmon (Oncorhynchus kisutch), prior to having these catchments harvested. In previous studies, low recapture rates were obtained (17-63%) of marked individuals withi n study reaches. In 1998, a two-way weir system (involving two weirs) was placed below the natural migratory barrier in one of these three tributaries, to determine the extent and direction of movement in and out of the reach (466 m length) by the salmon id species inhabiting this stream. Daily monitoring, during the months of June, July and August, revealed that each species moved in and out of the study reach with most movement by young of the year (YOY) fish (>90%). Brook charr comprised approximatel y 70% of the catch in each direction. Movement was associated with increases in stream flow. Upstream movement was notable during a minor flow increase (4 fold) in the summer (averaging 6.7 fish/day) and, was accentuated during major increases (8-30 fo ld) in the latter part of the spring and summer (averaging 15.5 and 13.8 fish/day, respectively). Downstream movement was only notable during the major flow increases in the latter part of the spring and summer (averaging 7.7 and 6.7 fish/day, respective ly). The highly mobile nature exhibited by YOY salmonids in this study should be considered when assessing land-use impacts on salmonid stream habitat.

Morrison, Bruce J. and Stephen S. Crawford. Axelrod Institute of Ichthyology, University of Guelph, Guelph, Ontario.

OPTIMAL SAMPLING OF COMMERCIAL CATCH FOR LAKE WHITEFISH ASSESSED AT ONE LOCATION.(P)

Lake whitefish is a culturally and economically important fish to the Chippewas of Nawash First Nation. Their commercial fishery surrounds the Bruce Peninsula in Lake Huron and it has historically been divided into five management zones. Sampling is typically conducted at a single assessment location. Approximately 5% (1 in 20 fish) of the entire catch is sampled, regardless of the size of the total catch. The efficiency of this sampling protocol is compared to alternative designs, including one- a nd two-stage sampling using management zone (primary unit) and fishing event (secondary unit). Cost to the fishing operations and the assessment program is also incorporated within the design.

Rankin, K.R. and R.W. Mackereth. Faculty of Forestry and Centre for Northern Forest Ecosystem Research, Lakehead University, Thunder Bay, ON.

THE RELATIONSHIP AMONG PHYSICAL AND HYDROLOGICAL STREAM AND DRAINAGE BASIN CHARACTERISTICS AND RIPARIAN VEGETATION STRUCTURE (P)

To examine the relationship in Ontario's Boreal forest among riparian vegetation structure and physical and hydrological stream and drainage basin characteristics, vegetation and stream surveys were completed at 40 streams having 1, 10, 40, and 100 km 2 watersheds. Characteristics of the watersheds including drainage area, relief and shape, a measure of surface roughness, area of lakes and wetlands, surficial geology, % forest cover types, and cutover area were collected using Geographic Information S ystems (GIS). We hypothesized that select drainage basin characteristics, along with riparian vegetation community type and structure will show a direct relationship with stream habitat characteristics. We also tested the hypothesis that smaller scale ( 1-10 km2) drainage basins and the surrounding riparian zone will have a greater influence upon stream habitat characteristics than larger scale (10-100 km2) watersheds. A model will be calculated from the acquired data which predicts the susceptibility o f a stream to disturbance by harvesting practices using GIS.

Shepherd, T., Page, F. and MacDonald, B. Biology Dept., Centre for Coastal Studies and Aquaculture, University of New Brunswick, Saint John, New Brunswick.

DISTRIBUTION OF SPINY DOGFISH (SQUALUS ACANTHIAS) IN THE BAY OF FUNDY AND SCOTIAN SHELF IN RELATION TO HYDROGRAPHIC VARIABLES. (P)

Changes in various environmental factors are known to influence the spatial distribution of many fish species. Using standard groundfish bottom trawl survey data (1970-97) environmental preferences of Spiny dogfish were objectively analyzed. Prelimina ry analysis showed that dogfish consistently selected water of relatively high temperatures. Preferred salinities and depths seemed to vary with available temperatures. We concluded that Spiny dogfish are "temperature keepers". This is a significant findi ng when considering both long and short term changes in continental shelf bottom water temperature.

Steinhilber, M. and J. S. Nelson. Department of Biological Sciences, University of Alberta, Edmonton, Alberta

AN ECOMORPHOLOGICAL ASSESSMENT OF CISCO (TELEOSTEI: SALMONIDAE) IN NORTHEASTERN ALBERTA (P)

Sympatric forms of cisco in two small northern Alberta lakes were examined morphologically and ecologically to assess whether any are species distinct from the widespread Coregonus artedi. One of these populations (in Barrow Lake) was previously ident ified provisionally as C. zenithicus. In both lakes, highly significant differences between sympatric forms were found in gill raker number as well as other counts and body proportions. Despite differences in adult body size and growth rate, no evidence w as found to support the hypothesis that different feeding strategies have induced non-genetic modification of key morphological characters in sympatric forms. Morphological distinctiveness, lack of apparent intergrades, and little evidence for ecophenotyp ic modification suggest the forms within each lake represent separate gene pools. The putative C. zenithicus in Barrow Lake differs in a number of characters from a sample of Great Lakes C. zenithicus and from the paratype, but is likely an unusual form o f this species.

Wisenden, B.D., Stacey, N.E., McCutchen, N.A. and C.A. Paszkowski. Department of Biological Sciences, University of Alberta, Edmonton, AB. P6G 2E9

ASSESSMENT OF OILSAND WASTE WATER ON OLFACTORY FUNCTION IN FISHES (P)

Environmental assessment of industrial activity is key to the responsible and longterm management of both industry and the natural resources it affects. A relatively unexplored area of environmental impact is the potential for interference by industri al effluents on responses to biologically important odourants. In this preliminary study, 5-year old tailings pond water (TPW) from the Syncrude Canada Ltd. oilsand operation in Fort McMurray, Alberta, was tested for potential effects on fish responses to three classes of odourants: (1) food odours, (2) alarm pheromones and kairomones that mediate predator-prey interactions, and (3) hormonally derived sex pheromones (steroids and prostaglandins). Electro-olfactogram (EOG) recordings showed that acute expo sure to TPW consistently and dramatically reduced the magnitude of EOG response to all tested odors. However, behavioral bioassays failed to detect any effect of TPW on odor-induced feeding, alarm reaction, or sex behavior. Despite these apparently contra dictory findings, these pilot studies provide an example of a novel, inexpensive, sensitive and biologically relevant approach to environmental impact assessment.