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Feeding dynamics of larval Pacific herring ( Clupea pallasi ) on natural prey assemblages: the importance of protists
Author(s) -
FRIEDENBERG LAURA E.,
BOLLENS STEPHEN M.,
ROLLWAGENBOLLENS GRETCHEN
Publication year - 2012
Publication title -
fisheries oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 80
eISSN - 1365-2419
pISSN - 1054-6006
DOI - 10.1111/j.1365-2419.2011.00611.x
Subject(s) - biology , pacific herring , predation , larva , clupea , veliger , herring , ecology , copepod , acartia tonsa , zoology , ichthyoplankton , clupeidae , fishery , crustacean , fish <actinopterygii>
The role of protists in the diet of larval Pacific herring ( Clupea pallasi ) was examined in laboratory incubations conducted in May and June 2008 using a natural assemblage of microplankton (10–200 μm). Available prey consisted of protists (diatoms, dinoflagellates, aloricate ciliates, and loricate ciliates) and metazoans (trochophores, bivalve larvae, rotifers, copepod nauplii, and gastropod larvae). We used a prey enumeration technique that included soft‐bodied heterotrophic protists (aloricate ciliates and athecate dinoflagellates) in the diet. We observed significant consumption of aloricate ciliates, loricate ciliates, bivalve larvae, dinoflagellates, and other available prey 73–200 μm. Clearance rates (mL larva −1 h −1 ) and an electivity index E* were used as measures of prey selectivity. The herring larvae showed strong selection for bivalve larvae and 73–200 μm available prey; however, across all valid experiments, protist prey were selected for at rates comparable to metazoans. Ingestion rates (μg C larva −1 h −1 ) showed that the majority of larval carbon intake was from diatoms and aloricate ciliates. The results of this study illustrate that there is a direct trophic link between larval herring and the microbial food web, and protists may make up a substantial portion of the larval fish diet, possibly alleviating food limitation.