Growth of Silver Eels (Anguilla rostrata) in Two Areas of Newfoundland

Abstract

Seaward-migrating American (silver) eels were collected with fyke nets in Dog Bay and Holyrood Bay on the northeast and south coasts of Newfoundland. In both areas, silver eels evidently undertake their spawning migration at ages 9 to 18 years (mean 12.9 yr), but the mean length and weight of eels from Dog Bay were significantly larger than those from Holyrood Bay. The smallest silver eel in the samples was 56.9 cm long, and all specimens were considered to be females because there are no records of males longer than 40 cm from Newfound land waters. Growth of silver eels from the two areas was compared with the growth of silver and yellow (immature) eels from the Topsail area (near S1.John's) in an earlier study. The size of the watersheds, inhabited by the eels prior to migration, may partly be reflected in the size of eels at the time of migration, because growth of eels was evidently faster in the area with the largest watershed than in the areas with smaller watersheds, probably reflecti ng variation in competition for food and space. Orbit diameter of silver eels from Newfoundland was larger than those of non-silver eels of the same size range from Lake Ontario, indicating that size of the eyes increases with onset of maturity.

Life History of American Eels from Western Newfoundland

“…The accuracy and precision of VBGF parameter estimates improve with increasing sample size, and estimates of L ' and theoretical age at a length of zero (t 0 ) depend greatly on the extremes of the length and age distributions. The sample size for age (and length) is relatively low, potentially biasing the VBGF parameter estimates, but the extremes of the length and age distributions for female silver eels compare well with those at other Newfoundland sites (Gray and Andrews 1971;Bouillon and Haedrich 1985).…”

“…The lengths, weights, and ages of American eels from two sites in western Newfoundland varied by sex, maturation stage, and habitat, primarily because the eels from Muddy Hole were mostly yellow juvenile eels and those from the Castors River were mostly silver maturing eels. Such differences due to life stage and geographic variability in habitat productivity and environmental conditions are well documented (Tesch 1977;Helfman et al 1987;Vøllestad 1992), including those for rivers in Newfoundland (Gray and Andrews 1971;Bouillon and Haedrich 1985).…”

“…Few studies exist of American eels in Newfoundland; three published studies focus on sites in eastern Newfoundland Andrews 1970, 1971;Bouillon and Haedrich 1985), and unpublished studies examine the biology and commercial fishery for eels on the southwestern coast (Brennan 1976) and the general commercial eel fishery (Fletcher and Anderson 1973). The Newfoundland sites are among the most northerly described in the literature.…”

Simulation of the Impact of Dams and Fishing Weirs on Reproductive Potential of Silver-Phase American Eels in the Kennebec River Basin, Maine

“…The hypothesis of Helfman et al (1987) that males are rare upriver of the estuary and females are distributed throughout a basin has never been carefully tested. Silver American eel runs from freshwater portions of rivers in the northern portion of their geographic range may be predominantly females (Smith and Saunders 1955;Bouillon and Haedrich 1985;Jessop 1987) or males (Krueger and Oliveira 1997;Oliveira and McCleave 2000).…”

Annual and Monthly Variation in Species Composition and Catches of Fishes from the Tabusintac River Estuary in the Southern Gulf of St. Lawrence

“…In Canadian waters, females can exceed 100 cm whereas males seldom exceed 61 cm (Scott and Scott 1988). Bouillon and Haedrich (1985) did not report any males over 40 cm from Newfoundland rivers. If these observations are applicable to the Tabusintac River then the majority of Eels caught in our study, most of which were greater than 60 cm, were predominantly female.…”