D.F. Bertram
Scott A. Hatch
M.J. Hipfner
L. Slater
W.J. Sydeman
Y. Watanuki
J.A. Thayer
2008
<p><span>We tested the hypothesis of synchronous interannual changes in forage fish dynamics around the North Pacific Rim. To do this, we sampled forage fish communities using a seabird predator, the rhinoceros auklet (</span><span class="named-content" data-type="species">Cerorhinca monocerata</span><span>), at six coastal study sites from Japan to California. We investigated whether take of forage fishes was related to local marine conditions as indexed by sea surface temperature (SST). SST was concordant across sites in the eastern Pacific, but inversely correlated between east and west. Forage fish communities consisted of anchovy (</span><span class="named-content" data-type="genus">Engraulis</span><span> spp.), sandlance (</span><span class="named-content" data-type="genus">Ammodytes</span><span> spp.), capelin (</span><span class="named-content" data-type="genus">Mallotus</span><span> spp.), and juvenile rockfish (</span><span class="named-content" data-type="genus">Sebastes</span><span> spp.), among others, and take of forage fish varied in response to interannual and possibly lower-frequency oceanographic variability. Take of primary forage species were significantly related to changes in SST only at the eastern sites. We found synchrony in interannual variation of primary forage fishes across several regions in the eastern Pacific, but no significant east–west correlations. Specifically in the Japan Sea, factors other than local SST or interannual variability may more strongly influence forage fishes. Predator diet sampling offers a fishery-independent, large-scale perspective on forage fish dynamics that may be difficult to obtain using conventional means of study.</span></p>
application/pdf
10.1139/F08-076
en
Canadian Science Publishing
Forage fish of the Pacific Rim as revealed by diet of a piscivorous seabird: Synchrony and relationships with sea surface temperature
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