—We estimated the variation in instantaneous rates of growth (G) and mortality (M) between intraannual cohorts of juvenile American shad Alosa sapidissima in the Pamunkey River, Virginia. The ages of juveniles captured by push net during the juvenile abundance index surveys in 1998 and 1999 were estimated by counting daily rings on the sagittal otoliths. Weight-at-age and abundance-at-age data ...

Alewife Alosa pseudoharengus, a small clupeid fish native to Atlantic Ocean, has recently (∼150 years ago) invaded the North American Great Lakes and despite challenges of freshwater environment its populations exploded and disrupted local food web structures. This range expansion has been accompanied by dramatic changes at all levels of organization. Growth rates, size at maturation, or fecund...

Artificial barriers on lowland rivers impede the spawning migrations of anadromous fishes, preventing access to historical areas. In cryptic European shads Alosa alosa and fallax (‘shad’ hereafter), this has resulted in population declines across their range. Conservation programmes aim facilitate passage migrators over these so require baseline information spatial temporal extent current migra...

Adaptation to freshwater may be expected to reduce performance in seawater because these environments represent opposing selective regimes. We tested for such a trade-off in populations of the Alewife (Alosa pseudoharengus). Alewives are ancestrally anadromous, and multiple populations have been independently restricted to freshwater (landlocked). We conducted salinity challenge experiments, wh...

Ultraviolet-sensitive vision (UVS), believed to have evolved from an ancestral state of violet-sensitive vision (VS), is widespread among terrestrial birds, where it is thought to play a role in orientation, foraging, and sexual selection. Less is known, however, about the distribution and significance of UVS in seabirds. To date UVS has been definitively demonstrated only in two families (Lari...