The Isopod Mesidotea entomon in the Chignik Lakes, Alaska

• Published in: Journal of the Fisheries Research Board of Canada
• Main Author: Narver, David W.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1968
• Subjects: General Medicine; Arctic; Lower Lake; Alaska
• Online Access: http://dx.doi.org/10.1139/f68-010; http://www.nrcresearchpress.com/doi/pdf/10.1139/f68-010

Studies on the isopod Mesidotea entomon (Linnaeus) from 1961 to 1964 in the two Chignik lakes, Alaska, showed that at least part of the population was benthic during daylight and pelagial at night. In Chignik Lake the isopod was most abundant in association with organic and mud bottoms and areas where salmon carcasses accumulate. Abundance decreased from early to late summer, perhaps because of a postreproductive mortality. It is suggested that males grow faster than females, though both sexes mature at age I+ and that growth terminates with maturation. Most reproduction apparently occurs in early summer but some ovigerous females were found as late as September. Length at maturity in both sexes was less than reported by other workers in Arctic marine populations. Mature isopods were smaller in the upper lake (males 40–46 mm, [Formula: see text]; and females 29–38 mm, [Formula: see text]) than in the lower lake (males 41–65, [Formula: see text]; and females 29–47 mm, [Formula: see text]) of the Chignik River system. Females in the upper lake had a higher average fecundity and a greater increase in fecundity per unit increase of length than those in the lower lake.