|Biological Characteristics and Population Status of Anadromous Brook Trout (Salvelinus fontinalis), 66 Years after an Initial Study in Moser River, Nova Scotia, Canada
John L. MacMillan and Reginald J. Madden
Nova Scotia Department of Fisheries and Aquaculture, NS, Canada
Brook trout Salvelinus fontinalis are the most popular native sport fish in Nova Scotia. A decline in the annual catch of brook trout since the early 1980s may reflect a change in the resource. Nova Scotia’s relatively short river systems are believed to facilitate anadromy in many brook trout populations and these trout are important to the sport fishery. Live release traps and water quality measurements were used to assess brook trout population parameters and habitat in the same locations as in the historical studies conducted on the Moser River by Leverin (1939), White (1940 and 1941), Huntsman (1942), and Wilder (1952). In 2006, the timing of anadromous brook trout migration was similar in comparison to White’s study: downstream migration occurred in May and most upstream migration occurred in July. However, a greater proportion of upstream migrating brook trout were detected in June in 2006 compared to June of 1939 to 1941. The number of brook trout trapped per day in Mill Brook, a major tributary of Moser River, suggests that the median number of anadromous brook trout had declined in 2006 (1.5) compared to 1940 (9.5) and 1941 (18). A significant difference was detected in the number of brook trout trapped per day in 2006 compared to 1940 and 1941 (P< 0.05). Relative stock density of brook trout indicated that large trout in the 2006 population was less than that of historical levels. The proportion of brook trout (fork length >300 mm) captured migrating upstream was 3% in 2006 which was significantly less than 26% in 1940 (P< 0.05), and 27% in 1941 (P< 0.05). In 2006, fork length of anadromous brook trout was 221 mm ±25 (mean, SD) at two years of age and 276 mm ±34 (mean, SD) at three years of age and was similar to mean fork length at age from 1939 to 1943. The oldest brook trout aged was four years in 2006 and six years in 1939 to 1943. A maximum age of four years, for the 2006 study, was consistent with other recent studies on anadromous brook trout populations in Nova Scotia.
During low flow periods in August, Moser River pH was 6.5 (0.35,SD) in 1939 and was 5.7 (0.15, SD) in 2006. Diatom inferred pH from a paleolimnological assessment of Mill Lake, located upstream of the Mill Brook trapping site, indicated an increase in acidity by a decline of pH 0.7 units from pH 6.8 in the 1930s. Diatom inferred Gran alkalinity changed from a pre impact range of 4.1 7.2 mg/L to a present day 0.6 mg/L (Ginn, Personal communication). Water temperature was warmer in 1939 compared to that in 1940 41 and 2006. In 1937 and 1939, mortality of salmon and trout in the Moser River occurred during warm low flow conditions (Huntsman 1942). A warming trend occurred over the past 140 years and the summers of 1937 and 1939 were two of the warmest on record for the Halifax region (Environment Canada).
Changes in environmental conditions and exploitation may have influenced the size and age structure of the Moser River anadromous brook trout population.
Nova Scotia’s L2F (Learn to Fish) Program
Nova Scotia Department of Fisheries& Aquaculture, Inland Fisheries Division, Pictou, NS
Recreational Sportfishing has been in decline throughout many areas in Canada. Western provinces have addressed this issue by developing programs to engage youth and implement more interest around this life-long activity. Nova Scotia has taken initiative to increase sportfishing by introducing a youth fishing program.
Learn to Fish was first launched in 2006 and concentrated in the area around Halifax Regional Municipality. Thanks to the success of the pilot project the program was expanded this spring and over twenty sportfishing workshops were held this year throughout Nova Scotia stretching from Sydney to Shelburne.
L2F was designed to promote and develop the recreational sportfishery of Nova Scotia. L2F is aimed at youth, 12 years old and younger, to provide them with the education and skills needed to enjoy sportfishing. The program has two main components: a classroom presentation and an outdoor lesson. The classroom presentation includes local sportfish, habitat and fishing basics. The outdoor lesson is a hands-on sportfishing session at a local lake. L2F workshops were held in schools, youth group clubs, community groups and science/nature camps.
Teachers found the material complementary to topics in curriculum and reinforced healthy, outdoor living. L2F recruits the next generation of stewards of aquatic resources by teaching safe angling skills. L2F’s objective is to introduce youth to sportfishing in a fun, safe environment with mentors that can teach basic angling. L2F’s goal is to ensure youth have a positive sportfishing experience.
Nutrient reserves and helminths of lesser snow geese.
DAVE SHUTLER, Dept. Biol., Acadia Univ., Wolfville, NS
RAY T. ALISAUSKAS, Cdn. Wildl. Service and Dept. Biol., Univ. Saskatchewan,
J. DANIEL McLAUGHLIN, Concordia Univ., Montreal, QC.
Costs of parasitism are predicted to be higher with higher parasite loads, and with more virulent parasites. Greater virulence may be favored at higher host densities and with greater inter parasite competition (diversity). We tested whether higher helminths loads were associated with reduced nutrient levels (indexed by lipids, protein, minerals, and true body mass) of host lesser snow geese, Chen caerulescens caerulescens. As part of a larger study on nutritional ecology, 771 wintering or migrating geese were shot between Jan and May 1983 in 27 different date locations (hereafter, samples) in a south north gradient from mid continental North America. Nutrient levels and parasite communities varied substantially among samples, so we analyzed data within each sample, controlling for structural body size (first principal component of 10 body size measurements), sex, and age. There was no compelling evidence that trematodes, cestodes, or helminth diversity were associated with significant variation in nutrient levels, but
nematodes appeared to negatively affect fat loads. However, associations between fat reserves occurred most often in geese collected between Mar and May when nematode prevalence and intensity were lower. This suggests that the most common nematodes (Heterakis dispar and Trichostrongylus tenuis) were more virulent later in the year, that infected individuals had been chronically infected and suffered cumulative nutrient losses, or that geese became more vulnerable to effects of parasites later in the year, possibly
because they redirected resources away from immunity in anticipation of reproduction.
Maritimes Breeding Bird Atlas
Maritimes Breeding Bird Atlas Coordinator
P.O. Box/ B.P. 6227, 17 Waterfowl Lane
Phone/Tel: 506 364 5045, 1 866 5atlas5
The Maritimes Breeding Bird Atlas is a five year, volunteer based project to assess the distribution, abundance and status of birds breeding in Nova Scotia, New Brunswick and Prince Edward Island. A first Maritimes Breeding Bird Atlas was done between 1986 and 1990 and still provides the most up to date distributional information for many Maritimes bird species. Field work for the second Atlas began in the spring of 2006 and will continue through 2010. Volunteers collect breeding evidence data using standardized field methodology, based on a 10 by 10 km square UTM grid system. Thus far, 700 volunteers have spent 13,000 hours surveying the Maritimes for breeding birds. Preliminary results, including new breeding species and changes in species distributions, as well as future applications will be discussed.
Trans-Atlantic migration of Atlantic salmon (Salmo salar) within the North Atlantic Gyre
Aaron D. Spares*, Michael J. W. Stokesbury, and Michael J. Dadswell
A.D. Spares: Biology Department, Acadia University, Wolfville, NS B4P 2R6, Canada; E-mail: email@example.com
The currently accepted marine migration model for Atlantic salmon proposes southern European stocks (<62oN) migrate in relatively straight lines from natal rivers to feeding grounds off West Greenland while Northern European stocks (>62oN) feed within the Norwegian Sea. North American stocks migrate directly to waters off West Greenland in summer and over-winter in the Labrador Sea and off the Grand Banks west of 44oW. Contrary evidence has led us to agree with an alternative trans-Atlantic migration hypothesis proposed by Reddin et al., 1984b. This hypothesis suggests North American and European salmon enter the North Atlantic Gyre on their respective sides to travel counter-clockwise with surface currents around the entire gyre before maturing and returning home. Evidence supporting this hypothesis includes distribution of catches and tag returns in former fisheries, and recent post-smolt catches in the Norwegian Sea. Tagging and scale discrimination studies demonstrated mixed continental stocks feeding on both sides of the North Atlantic. Salmon tagged as smolts in North America have been recaptured off Norway (n = 2) and the Faroes (n = 4) whereas adult fish tagged off the Faroes were recaptured in Canadian rivers (n = 4). Southern European tagged smolts were recaptured off Labrador and Newfoundland (n = 8). A study of bioaccumulated caesium-137 (137Cs) in a Quebec river population estimated 43% fed east of Iceland (~15oW). Recent 137Cs concentrations of Canadian (n = 143) and Irish salmon (n = 30) suggested 14.2% and 10.0%, respectively, fed east of the Faroes (~8oW) before homeward spawning migrations. Higher resolution research on marine migration of Atlantic salmon using acoustic/archival tags is necessary to test these two models.
Early results of the West River, Sheet Harbour, NS acid mitigation project.
Acid Precipitation negatively affects Atlantic salmon (Salmo salar L.) and other aquatic organisms. As stream acidity has not decreased with decreasing industrial emissions, immediate mitigation initiatives are required for the persistence of some salmon populations. The Nova Scotia Salmon Association’s West River, Sheet Harbour Acid Mitigation project was designed to treat the once prolific salmon river.
A monitoring program was conducted over 2.5 years to assess the early impacts of lime additions to the downstream aquatic communities. While signs of salmon recovery are assumed to require at minimum 3.5 years, preliminary signs of recovery were shown in stream chemistry and aquatic invertebrate communities. Acidity levels were reduced to those conducive to successful juvenile Atlantic salmon survival. Downstream aquatic invertebrate communities increased in abundance and realized shifts in relative dominance of some taxa, with the resurgence of those presumably the most acid sensitive. With river conditions ameliorated, the spring of 2007 marked the start of a live gene banking program, aimed at providing a sound method of re-seeding the river with this genetically distinct salmon stock. The West River pilot project is an essential “next step” towards the protection of Southern Uplands salmon stocks and was designed to demonstrate the feasibility of this modern liming technique as well as the role of liming in salmon river restoration.
THE ELUSIVE EASTERN RIBBONSNAKE: METHODOLOGY, MOVEMENTS, AND HABITAT USE
Tara L. Imlay* and Thomas B. Herman
Department of Biology, Acadia University, Wolfville, NS, B4P 2R6, firstname.lastname@example.org, email@example.com
The Eastern Ribbonsnake (Thamnophis sauritus) is fairly common throughout most of its range. However, at the northern limit of the range, the highly disjunct Nova Scotia population has been listed as Threatened federally (SARA) and provincially (NS Endangered Species Act). Despite its common status, few studies have focused on the habitat requirements and movement patterns of this species, probably due in part to its cryptic nature. The large knowledge gap surrounding habitat use and movement patterns has made identifying the appropriate actions for protection and recovery of the species a challenge. In 2006, a high density site of Eastern Ribbonsnakes was identified on Molega Lake, which also supports a high density of lakeshore cottages. We have tested the effectiveness of using external radio-transmitters, fluorescent powder tracking, and visual surveys to obtain information on habitat use and movement of ribbonsnakes at this site. Several difficulties were encountered during radio-transmitter attachment, including the loss of transmitters within 24 hrs of attachment and impaired movement in some individuals. Powder tracking and visual surveys provided fewer logistical difficulties, but have inherent biases. Despite difficulties with methodology, we have managed to collect information on movement and habitat use of ribbonsnakes during various stages of their life history at a site experiencing considerable human disturbance. Additionally, work at the site has generated public interest in the species and provided significant stewardship opportunities.
Detecting the genetic consequences of shoreline degradation in Nova Scotian populations of the rare plant, Sabatia kennedyana (Fern.).
Jolene T. Sutton and Sara Good-Avila
Department of Biology
24 University Ave.
Wolfville, Nova Scotia
Morphology and genetics of the threatened plant, Sabatia kennedyana (Fern.), were examined to test for effects of human-mediated habitat disturbance in Nova Scotia. Although theory predicts that habitat fragmentation will lead to the loss of genetic diversity, there were no differences in either genetic or morphological variation between naturally-disturbed and human-disturbed sites. However, because traditional genetic diversity estimates reflect historical levels of variation that have built up in populations over many generations, they may be insensitive to the effects of contemporary landscape changes. In genetic analysis, spatial autocorrelation can be used to estimate the relatedness between pairs of individuals based on their multilocus genotypes, and provides a method for comparing the spatial genetic structuring among populations. For Nova Scotian populations of S. kennedyana, comparison of the regression slopes of relatedness against distance revealed that intra-population spatial genetic structuring was deteriorating in anthropogenically-disturbed shoreline habitats. These results suggest that human-modified sites may suffer from 1) reductions in seed bank viability, 2) increased plant mortality, and/or 3) reductions in clonal patch size/structure. By incorporating a spatial component to our analysis of genetic data we were able to detect consequences of contemporary habitat disturbance before the predicted changes in overall genetic diversity could occur. This research reveals one method for early identification of fragmentation effects, and may allow for more proactive conservation management.
Population Characteristics and Movement of Atlantic sturgeon in Minas Basin, Bay of Fundy during Summer.
Sierra Wehrell, Adrien Rawley, Aaron Spares, Anna Redden and Michael Dadswell
Dept. of Biology, 24 University Avenue, Acadia University, Wolfville, NS B4P 2R6
Atlantic sturgeon (Acipenser oxyrinchus) are known to migrate into the Bay of Fundy but little is known about the sturgeon found in Minas Basin. Fisheries research projects in Minas Basin have shown that Atlantic sturgeon are common in the Basin between the months of May and September. Trawl surveys during 2004 and 2005 caught 57 sturgeon; 33 of which were measured and tagged with dart tags. The mean fork length of captured sturgeon was 1342.5 ± 203.5mm in 2004 and 1369 ± 181.3mm in 2005. A directed sturgeon study was commenced in 2007 during which a total of 144 sturgeon were caught. Of these 54 sturgeon were captured in weirs in the Five Islands region on the north side of the Basin and 90 were caught by trawling between Blomidon and Avonport in the southern Basin. Of these, 121 sturgeon were tagged, measured, and tissue samples taken for DNA analysis. Mean fork length of sturgeon captured in the weir was 1184 + 326.2 mm and of those caught by trawling, 1377.8 + 194.6 mm. Trawl catches during the 3 years were not significantly different but were different from those captured in the weir during 2007 (t-test, p>0.05). Two sturgeon were recaptured in the southern Basin during 2007 after being tagged in Five Islands and at large 1-2 months. A Petersen estimate suggests a population of approximately 1650 sturgeon occurred in the Basin during the summer of 2007. During 2005 and 2007 pectoral spines were removed from the sturgeon for ageing and we will analyze these in the near future. Further sampling during 2008 will complete our information on the population characteristics for the summer, Minas Basin sturgeon population. We anticipate that distant tag returns and/or DNA analysis will provide us with clues for the origin of this group of Atlantic sturgeon.
Managing Dairy Cattle Pasture for Biodiversity.
Alan H. Fredeen1, Sina Adl2, Kathleen Aikens3, Nicole Arsenault2, Thomas
Bouman3, Gaëtane Carignan1, Cathy Conrad4, Clayton D'Orsay6, Caroline
Halde1, Andrew Macdonald3, Anthony Mazzocca5, Ralph Martin1, David
McCorquodale3, Nancy McLean1, Aaron Mills2, Yousef Papadopoulos5, Sheena
Townsend3, Peter Tyedmers2 and Julien Winter1.
(1) Nova Scotia Agricultural College, Truro, NS; (2) Dalhousie
University, Halifax, NS; (3) Cape Breton University, Sydney, NS; (4) St.
Marys University, Halifax, NS; (5) Agriculture and Agri-Food Canada;
Charlottetown, PE (6) UPEI, Charlottetown, PE
Complexity in agricultural landscapes maintains biodiversity of insects, birds, plants and soil biota. Grasslands and pastures are particularly important for biodiversity because they provide large, unique areas of habitat, that are much less disturbed than cropland. In 2004, a five-year study began in Truro, Nova Scotia into managing dairy cattle pasture for biodiversity. One component of the study is looking for complementary grass mixtures to improve pasture yield and conservation of soil mineral nitrogen. Another experiment has created a multi-habitat pasture with intensive defoliation, conventional defoliation, and lax defoliation management of the pasture sward. Botanical diversity was decreased by lax defoliation, but only on more productive paddocks in the pasture. Plant residue decomposition in the soil was dominated by fungi under lax defoliation, and bacteria under intensive defoliation. Using dairy cattle to create this multihabitat pasture had no significant effect on cow health or milk yield. On a broader scale, a
life-cycle assessment compared the environmental impact of milk production from cows confined year-round to cows pastured for five months of the year. While the two systems were similar in impact, a movement to less reliance on high-energy feed and more pasture was suggested.
1Public Involvement in Mainland NS Moose Recovery Efforts
Anthony (Tony) L. Nette
Manager, Wildlife Resources
136 Exhibition Street,
Kentville, Nova Scotia
Ph# (902) 679-6140
As stated in the Recovery Plan for Moose (Alces alces americana) in Mainland Nova Scotia, March, 2007:
“Governments and researchers alone will not be effective in recovering this species. Success will depend on a high level of awareness and strong determination within the general public of Nova Scotia to maintain and enhance conditions for moose numbers to increase.” And, “For recovery to be successful, stewardship and cooperation between First Nations, industry, governments, and the public is essential.”
A “draft” communications plan, including approaches to education, public awareness, reporting sightings and illegal hunting, and engaging landowners in stewardship of moose and their habitat, will be presented.
Causes of high nest failure of endangered Piping Plovers in southern Nova Scotia.
Sue Abbott1 & Julie McKnight2
Bird Studies Canada, Dartmouth NS; firstname.lastname@example.org
Canadian Wildlife Service, Dartmouth NS; email@example.com
The Piping Plover (Charadrius melodus melodus) is an endangered shorebird that breeds on coastal beaches throughout Atlantic Canada. A reproductively-isolated sub-population of plovers, which currently represents approximately 65% of the province’s population, breeds in southern Nova Scotia (Halifax, Lunenburg, Queens, and Shelburne counties). Population estimates from the International Piping Plover Census show that approximately 56 plovers bred in southern Nova Scotia in 2006 - a decline of 27% since 2001 and a decline of 45% since 1991. Between 2000 and 2007, a total of 237 pairs and 321 nests were monitored in Lunenburg, Queens, and Shelburne counties. In most years, annual productivity for the region was below the minimum productivity target (1.65 fledglings per pair) estimated to be necessary to maintain the population at its current level. Over one half of all monitored nests failed to hatch and nest failure is, thus, a major factor limiting productivity. We examined the causes of nest failure and the performance of nest exclosures, used to protect eggs from predators, from 2000-2007. Predation was the leading cause of nest failure followed by abandonment and inundation due to tides. Through our examination, we hope to develop and implement beach-specific approaches that are informed by, and adapt to, natural and anthropomorphic changes over time.
Ducks Unlimited Canada’s Eider Initiative
Mark Gloutney and Katherine Mehl
Ducks Unlimited Canada, box 430 Amherst, NS. B4H 3Y4.
Ducks Unlimited Canada’s (DUC) Eider Initiative is designed to help fill gaps in our knowledge of Common Eider Somateria mollissima dresseri ecology. The study focuses on two area along the Newfoundland and Labrador coast. The study has the following objectives:
Calculate and assess geographical variation in adult female survival, seniority (proportion of population returning to breed each year), recruitment (proportion of first time breeders in the population), and overall population growth using CMR techniques.
Obtain estimates of breeding propensity (proportion of individuals breeding annually) using CMR techniques to obtain
Estimate juvenile/sub-adult survival.
Determine age at first breeding.
Identify a) the links between breeding and wintering areas, b) migration chronology, and c) migration pathways, as well as potentially locating moulting and wintering areas for females.
Four of five years of field work have been completed. To date, more then 2100 adults 8200 duckling and 750 preflight juveniles have been banded. Two hundred and sixty six direct band recoveries have been reported, with 90% of the harvest individuals being banded as ducklings or juveniles. Seventy three percent of the recoveries come from Newfoundland and Labrador.
European green crab populations in eastern Prince Edward Island:
variations among sites and along the spring-summer season
Vanessa Lutz(*), Lisa Rosenberg, Pedro Quijon
Department of Biology, University of Prince Edward Island, Charlottetown-PEI
The European green crab (Carcinus maenas) is an aggressive generalist predator of marine habitats. It successfully colonized New England, where it was associated with the decline of the soft-shell clam industry during the 1950s and subsequently expanded into the Maritimes. Since the 1990s the green crab has become an established population on the eastern shores of Prince Edward Island (PEI) where it threatens both the native diversity, and the fisheries and aquaculture industries. The green crab occurs in high abundances relative to many native crab species and is frequently the dominating species, significantly impacting the ecosystems where it colonizes. In order to describe recent populations of green crabs and their variation along the spring-summer season, we sampled six estuaries across PEI using a 30 m beach seine. At each estuary between May and September, we sampled six sites, including two inner, two outer, and two in the middle of the estuary. Green crabs were found in four of the chosen estuaries, all in eastern or southern PEI: Basin Head, Montague- Brudenell, Murray River, and Pinette. We compared green crab abundance, sex ratio, and size distribution between the four estuaries, and discuss these results in light of the recent success of this species’ spread to western PEI.
Assemblages associated to intertidal biogenic habitats and their potential disruption by an invasive species
Andrey Malyshev(*), Pedro Quijon
Department of Biology, University of Prince Edward Island, Charlottetown, PE
Beds and clumps of mussels and oysters are well known for aquaculture and recreational purposes along coastal Prince Edward Island (PEI). Their importance as habitats for invertebrate assemblages and for recruits of decapod crustaceans hiding from larger predators have, however, received less attention. The ongoing invasion of PEI’s coast by species such as the green crabs (Carcinus maenas), and their use of low-intertidal mussel and oyster beds as primary sites for seasonal recruitment may represent an influential structural factor on the invertebrate communities associated to these habitats. In order to understand the potential changes introduced by this invasive species, we first document the composition and abundance of communities associated to oysters and mussel clumps, and compared them with that of unstructured sediments on three coastal sites near Charlottetown, PE. We then discussed these differences in relation to the results of a preliminary green crab inclusion experiment conducted to test whether the presence and feeding by juveniles of this species produce any significant changes on communities associated to the most common of these habitats: the mussel clumps.
A survey of methods for modelling species occurrence, with an evaluation of their predictive power and generality.
Dr. David J. Lieske
Dept. of Geography and Environment, Mount Allison University
A survey of recent studies in species occurrence (distribution) modelling reveals the use of a wide range of modelling methods. The proliferation of so many approaches has resulted in uncertainty as to the most appropriate or useful method to adopt given a problem at hand. The purpose of this study was to provide an overview of the methods used to model species occurrence, and to illustrate the use of a number of traditional (logistic regressions and GAMs) and non-traditional, spatially-explicit modelling methods (spatially autocorrelated regression and geographically-weighted regression). Important questions included: how accurately do the models predict species occurrence, and how generalizable are they when applied to different contexts? The accuracy assessment conducted for these methods highlights that the best modelling approach to use depends on the intended application of the predictions. For interpolation into regions that have been under sampled, simpler models may be less accurate than more complex models, but are potentially more general and reliable in their performance. In this study, habitat specificity and life history were also found to also be an important determinant of the suitability of different modelling approaches.
An Evaluation of the Ecological Responses Associated with the Salt Marsh Restoration Project in Musquash, New Brunswick, Canada.
Deanne M. Meadus1 and Jeff Ollerhead2.
1 Ducks Unlimited Canada, Amherst, NS. (firstname.lastname@example.org)
2 Mount Alison University, Sackville, NS. (email@example.com)
Construction of dykes and subsequent draining of wetland has resulted in the conversion of 65% of the Upper Bay of Fundy salt marshes to agriculture. Recently, there has been increasing interest to promote the restoration of these lost systems. As salt marsh restoration activities increase, a better understanding of physical and biological processes and anticipated outcomes have become imperative. With the introduction of full tidal influence to the 38-acre property complete, Musquash Marsh was an ideal location to address some of these knowledge gaps. Ducks Unlimited Canada and Mount Allison University developed a salt marsh evaluation program to assess changes in geomorphology, vegetation and the animal community. Two adjacent salt marsh segments served as reference sites. Changes in surface elevation were monitored through marker horizons, placed in the marsh before the restoration, using differential global positioning systems (GPS). Changes to marsh hydrology, measured by low-level aerial photographs and differential GPS surveys of channel cross-sections, and the depth of tidal inundation was measured using a water level recorder. Vegetation surveys were conducted to assess changes in vegetation height, density, and species composition. The avian community response to the restoration was evaluated. In addition, invertebrate surveys assessed the food availability in the restored salt marsh. Preliminary results of these variables will be discussed.
Conservation Genetics of the Freshwater Mussels, Pyganodon cataracta and Pyganodon fragilis, in Atlantic Canada.
Lily Stanton and Don Stewart
Acadia University, Department of Biology.
Wolfville, Nova Scotia
The presence and diversity of freshwater mussels are important indicators of a healthy aquatic ecosystem. Although freshwater mussels are distributed worldwide, they attain the greatest diversity in North America. Yet, despite their high diversity, Molluscs are among the most threatened groups of organisms in North America, with over 70% of species identified as endangered, threatened, or of special concern. The conservation status of many Canadian freshwater mussels, including some12 species of mussels found in Atlantic Canada, have not been directly assessed by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). Pyganodon cataracta (the Eastern Floater) and Pyganodon fragilis (the Newfoundland floater) are both found in Atlantic Canada but their taxonomic status and exact geographic distribution is uncertain. Historically, these species have caused considerable debate among taxonomists, due to very subtle morphological differences that exist between them and indeed some diagnostic characteristics, such as shell colouration and stomach anatomy, have shown to be unreliable. Given the difficulties in delineating freshwater mussels based on morphological traits, molecular techniques may be extremely useful for classifying species and our research will attempt to determine if P.cataracta and P. fragilis are two distinct species, just one species, or a mixed hybridizing population.
Northern Gannet Mortality from 1988 to 2007 Records from the Southern Gulf of St-Lawrence
Greg Campbell1, Tasha Armenta1, Pierre-Yves Daoust2 Julie Paquet3 & Becky Whittam1
1. Bird Studies Canada, Atlantic Region. P.O. Box 6227, 17 Waterfowl Lane, Sackville, NB, E4L 1G6
2.Canadian Cooperative Wildlife Heath Centre, Atlantic Veterinary College, UPEI
3. Canadian Wildlife Service. P.O. Box 6227, 17 Waterfowl Lane, Sackville, NB, E4L 1G6
Northern Gannets often wash up in large numbers on beaches in the southern Gulf of St. Lawrence, defined here as extending from the Baie des Chaleurs and the Northumberland Strait up to western Cape Breton and the Îles-de-la-Madeleine. A database of 378 gannet mortality records for the southern Gulf of St. Lawrence from August 1988 to May 2007 was created from various sources, including the Canadian Wildlife Service, necropsy records from the Atlantic Veterinary College, the New Brunswick birders’ listserve and Bird Studies Canada’s Maritimes Beached Bird Survey.
Exceptionally high numbers of birds were found in 1991 (98), in 1994 (43), and in 2003 (108). Over all years, the highest numbers of gannets were found in May and June, and no birds were recorded in January, February or March. The high numbers in May and June are mainly due to the records of large die-offs in the springs of 1991, 1994, and 2003. Nonetheless, when these exceptional years are removed from analyses, May and June still have the highest records of gannets.
Most identified birds were adults (80%), with some immature birds (7%) and hatch-year juveniles (13%). Atlantic Veterinary College necropsies and on-site assessment of causes of death revealed a cause of death for only 143 of all 378 gannets found in the southern Gulf of St. Lawrence. Over half (53%) of all diagnosed birds likely died of entanglement in fishing nets or hooks and almost all entangled birds were found in May and June. Remaining birds died of trauma, disease, or emaciation resulting from unexplained starvation. Only one gannet, from beached bird surveys off the west coast of Cape Breton, was found with evidence of oiling.
Biodiversity Assessment of Agricultural Riparian Areas, Upper Cornwallis River and Tributaries, Nova Scotia.
Kaitlin Almack, Graham Dixon-MacCallum
The Annapolis Valley has a long history of agricultural use with a recent increase in residential development. These land use patterns have caused the accumulation of pollutants in river largely from farmland runoff and more recently, public sewage outflow. We explored the relationship between terrestrial biodiversity, land use and agricultural practices along riparian areas. Riparian areas filter water, trap sediment and provide habitat for a variety of wildlife. We identified 17 study sites in 4 different ecotopes in riparian areas across the Tri-brook watershed, an agricultural area north of Berwick, NS. The Tri-Brook Watershed includes the tributaries of the Upper Cornwallis River. Birds and invertebrates were sampled as indicator species to assess terrestrial biodiversity. A point count bird survey was conducted in the month of June and in July terrestrial invertebrates were collected with pit fall traps. We also completed a Riparian Health Assessment at each study site and a plot-based vegetation survey. It is our hope to relate the diversity of birds, invertebrates and vegetation to the Riparian Health Assessment. Our study will provide useful information on how wildlife in terrestrial riparian ecosystems, respond to intensity of agricultural stress. Finally, this study will make recommendations for the modification of the Riparian Health assessment to include, criteria influencing terrestrial wildlife and will increase the local relevance of the health assessment.