Predation on walleye pollock ( Theragra chalcogramma ) eggs in the western Gulf of Alaska: the roles of vertebrate and invertebrate predators

摘要: Estimates were made of the predation rate upon eggs walleye pollock (Theragra chalcogramma) in Shelikof Strait western Gulf Alaska by midwater and near-bottom fish invertebrate predators during April 1990. Adult juvenile dominant (∼99% total abundance) planktivores collected samples. Based on visual inspection stomach contents, a high percentage sampled found to have consumed eggs. Daily egg consumption older age groups was estimated be <1% available at all sampling locations. The only other fishes consume flatfishes bottom trawls but their abundances very low. Gammarid hyperiid amphipods important water column, as determined immunoassays using antibodies developed specifically ascertain presence egg-yolk protein. Decapod shrimp showed proportion positive assays collections. Invertebrate may up 4% number near daily basis. Although we not able account for entire mortality this stock, our method combination techniques is promising terms future attempts estimating mortality.