| Gray seals (Halichoerus grypus) were historically distributed along the Northeast coast of the United States (U.S.) and Canada through the 17th century. They were considered locally extinct in U.S. waters until the 1980s, when naturally reestablished breeding colonies were observed on islands off of the Northeastern U.S. Here I present archaeological records indicating that gray seals were historically distributed along the Northeast United States Coast (from Maine to Connecticut). They currently pup at three established colonies: Muskeget Island, Massachusetts, Seal Island, Maine, and Green Islands, Maine. I used aerial survey data of these sites to document the current population status. A minimum of 2620 pups was born in the U.S. in 2008 Some of the local breeders have been observed with brands and tags indicating they had been born on Sable Island, Canada. I explored the possible contribution of immigration from Sable Island and local reproduction as sources of this population increase.;Two large populations in Canada (Gulf of St. Lawrence and Sable Island) are both possible sources of immigrants for the recovering U.S. population. To identify the source population for the U.S. gray seal population and to assess the stock structure of gray seals in the northwest Atlantic, tissue samples were collected from both Canadian and the U.S. populations for genetic analyses. I used a combination of nine highly variable microsatellite loci and a 320bp segment of the mitochondrial control region as molecular markers to show that there is little population differentiation in gray seals in the Northwest Atlantic.;Species characteristics and the availability habitat influence the degree of recovery in exploited species. Finally, I considered three factors that are key in recolonization: (1) the ability of the species to disperse; (2) life history parameters of the species including age at first reproduction, number of offspring produced per reproductive event, the frequency of reproductive events and life span; (3) environmental conditions that affect the species including hunting pressure and habitat quality. Examples of animals that are long lived and have low reproductive rates are discussed in light of these factors with special attention given to the gray seal. |
