Haldorson, L. J.. University of Alaska, ffljh@acad1.alaska.edu
Boldt, J. J.. Unversity of Alaska, fsjlb3@aurora.alaska.edu

 
PLANKTIVORY BY FISHES IN PRINCE WILLIAM SOUND, ALASKA: A BIOENERGETICS ANALYSIS
 
The vertebrate planktivore community in Prince William Sound is dominated by herring, a year-round resident. Pink salmon juveniles are summer transient planktivores that may be locally abundant. In the 1980's both species had sharp increases in abundance, and in 1992-93 the herring population crashed. The abrupt decline in herring may have been linked to stress resulting from food limitation. We used bioenergetic modeling to estimate Sound-wide plankton consumption by herring and pink salmon from 1985-1994. Consumption (wet weight) by pink salmon ranged from 0.53 to 0.87 g/m2/y, whereas herring consumed 65 to 318 g/m2/y. Prior to 1992, herring consumption always exceeded 250 g/m2/y; however, it dropped sharply to 65 g/m2/y in 1993. Prior to the population crash, herring were probably consuming over 30 % of herbivorous zooplankton production, and may have been at or over the carrying capacity of Prince William Sound. Pink salmon consume a relatively small proportion of Sound-wide zooplankton production, although localized prey depletion may be possible. The increase in hatchery production of pink salmon appears to have relatively little impact on overall zooplankton production in the Sound.
 
Day: Thursday, Feb. 4
Time: 09:30 - 09:45am
Location: Hilton of Santa Fe
 
Code: SS22TH0930H