From 1995 to 2006, US federal fisheries observers deployed aboard commercial fishing vessels in the US mid-Atlantic region documented captures of loggerhead Caretta caretta, green Chelonia mydas, Kemp's ridley Lepidochelys kempii, and leatherback Dermochelys coriacea turtles in commercial sink gillnet gear. Data collected by these observers were used to characterize sea turtle bycatch in sink gillnet gear, including the temporal and spatial distribution, fishing characteristics, species composition, and sizes of turtles captured. In addition, these data were used to develop a generalized additive model to evaluate and predict bycatch rates (turtles per metric ton of fish landed) of sea turtles. These rates were then applied to commercial gillnet landings over the same time period to estimate total bycatch of loggerhead turtles. Bycatch rates of loggerheads were correlated with latitude, sea surface temperature, and mesh size. Highest predicted bycatch rates occurred in warm waters of the southern mid-Atlantic, in large-mesh gillnets. From 1995 to 2006, the average annual bycatch estimate of loggerheads was 350 turtles (coefficient of variation = 0.20, 95% CI over the 12 yr period: 234 to 504). Characteristics and magnitude of bycatch can help inform population assessments, while the distribution of bycatch rates can be used to help inform bycatch mitigation options.
Gray seals were historically distributed along the northeastern coast of the United States, but bounties and lack of protection reduced numbers and they were rarely observed for most of the 20th century. Once protections were enacted, the population started to rebound. Here, we describe the recolonization and recovery of gray seals in the United States, focusing on the re-establishment of pupping sites. We fit individual generalized linear models to various time series (1988–2019) to estimate rates of increase in observed pup counts at four of the more data-rich sites. Annual rate of increase at individual sites ranged from −0.2% (95% CI: −2.3–1.9%) to 26.3% (95% CI: 21.6–31.4%). The increase in sites and number of pups born in the United States is driven by population growth and immigration from Canadian colonies and is part of a larger recovery of the Northwest Atlantic population. Wildlife protection, a healthy source population, habitat availability, and species traits that allow for dispersal and high productivity were all important factors in this recovery.
The northwest Atlantic subspecies of gray seal (Halicheorus grypus grypus) has been increasing for more than a half century and has reestablished breeding colonies in Canadian and US waters. In 2016, visual, oblique, and vertical large-format digital photographic surveys were conducted at all known breeding colonies in the northwest Atlantic. Total pup production in the northwest Atlantic was estimated to be 109,000 (SE = 17,500) pups. At 87,500 (SE = 15,100) pups, Sable Island accounts for 80% of total pup production. Regional differences in pup production trends are evident. Pup production in the Gulf of St. Lawrence and along the eastern shore of Nova Scotia has been relatively stable. Since 2004, the rate of increase in pup production at Sable Island has slowed to about 5%-7% per
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