Walleye pollock Gadus chalcogrammus Pallas, 1814 found north of Spitsbergen indicates a Pacific-Atlantic connection in the species

A small (36.5 cm) female walleye pollock Gadus chalcogrammus Pallas, 1814 was caught north of Spitsbergen in2011. The specimen had a high number of pyloric caeca (n=109), indicating a Pacific origin. The record is the firstevidence of a possible input to the small Atlantic population of walleye pollock from the large populations on thePacific side.

Northwest Atlantic mackerel population structure evaluated using otolith δ18O composition

The Northwest Atlantic mackerel (Scomber scombrus) population is comprised of northern and southern contingents, each with distinct natal regions in the United States and Canada. We tested hypotheses on natal origin and contingent mixing by analysing natal otolith δ18O values, evaluating the approach through an out-group comparison with the Northeast Atlantic population. Otolith δ18O values varied according to expectations between the Northeast (higher) and the Northwest (lower) Atlantic basins, and between contingents within the Northwest Atlantic stock, although contingent differences varied between years. Most adults (age-3+ years) sampled from US waters (1999–2003) represented the northern contingent (Canadian spawning site). The confirmation of the seasonal mixing of older and larger fish between the two contingents provides support and justification for the development of bi-national (United States–Canada) assessment and management of Northwest Atlantic mackerel.

Genetic population structure in Greenland halibut (Reinhardtius hippoglossoides) and its relevance to fishery management

Exploited marine resources can be managed more effectively when accurate information on geographic population structure is available. Genetic markers offer a powerful tool for fisheries management, because they reveal biologically sound management units. Single nucleotide polymorphisms (SNPs) markers derived from restriction-site associated DNA sequencing (RAD-seq) were developed and used to investigate the stock structure of Greenland halibut (Reinhardtius hippoglossoides). A total of 96 SNPs were analyzed from 384 individuals and eight locations across the Atlantic. Our results suggest a subdivision of Greenland halibut into two populations, an eastern Atlantic population and a western Atlantic population, with a proposed border across the Denmark Strait. In general, Greenland halibut display weak but significant population structure (overall FST = 0.003; p < 0.001), which can be explained by connectivity among populations owing to the migratory behavior or egg and larval drift.

Population decline of endangered lichen Erioderma pedicellatum in Nova Scotia, Canada

Erioderma pedicellatum (Hue) P.M. Jørg. (1972) is a globally endangered lichen known from only four countries worldwide. The Atlantic population in Nova Scotia, Canada, has been declining for at least the last few decades. The population was closely monitored between 2003 and 2012 to determine mortality rates by life stage and population growth. A population viability model was created to assess the future viability of this population. The population declined by 12.8% over the 10 year monitoring period. Mortality rates for juveniles were significantly lower than for adults. The population viability model suggests the population in Nova Scotia will decline by 49% within 25 years. Conservation measures aimed at prolonging adult survival or increasing juvenile survival is, according to the model, the best way to maintain the population.

Distribution and use of brood-rearing and moulting sites of the Atlantic population of Canada Geese (Branta canadensis) in Nunavik, Quebec

The Atlantic population of Canada Geese (Branta canadensis) nests in the coastal lowlands of eastern Hudson Bay and southwestern Ungava Bay in Nunavik, Quebec. Although many aspects of the nesting ecology of this and other northern populations of Canada Geese have been studied and published, there is a paucity of information on the use of brood-rearing and moulting sites. Based on 18 years of band and recapture data from an ongoing banding program, this paper presents the distribution of brood-rearing and moulting sites and the use of these sites over time. Along Hudson Bay and Ungava Bay, the most important brood-rearing and moulting areas are the stretch of coastal lowlands between the Mariet River and Shallow Bay and between Rivière aux Feuilles and Virgin Lake, respectively. Of all adult geese captured during the banding program (n = 41 924), 7.5% (standard error [SE] 0.13%) were recaptures, that is, birds that had previously been caught and banded; annual recapture rates ranged from 5.1% to 11.4%. The mean and median distances between the site of first recapture and the original site of capture were 4.3 km (SE 0.22 km) and 1.5 km, respectively. Juveniles moved, on average, 5.4 km farther than adults and males moved 1.4 km farther than females. Among geese banded as juveniles, males moved twice as far as females: 11.5 km versus 5.7 km.