Northwest Fisheries Science Center

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Document Type: Journal Article
Center: NWFSC
Document ID: 8254
Title: Does larval advection explain latitudinal differences in recruitment across upwelling regimes?
Author: Jennifer L. Fisher, William T. Peterson, Steven G. Morgan
Publication Year: 2014
Journal: Marine Ecology Progress Series
Volume: 503
Pages: 123-137
DOI: 10.3354/meps10732
Keywords: upwelling,Recruitment limitation,Larval supply,Advection,Larval behavior

Larval supply determines year-class strength of fisheries and complex ecological
interactions among adults of benthic marine species. In upwelling regions, a latitudinal cline in
the intensity and persistence of upwelling is thought to affect larval advection and recruitment,
thereby regulating the intensity of interactions in adult populations and communities. We tested
this hypothesis by determining the monthly cross-shelf abundances of nearshore benthic crustacean
larvae throughout development during the peak upwelling season for 7 years in a region
of intermittent upwelling and high recruitment (45°N). We tested whether larvae were found farther
offshore during upwelling conditions, and we compared their interspecific cross-shelf distributions
to previous results from a region of strong, persistent upwelling (38°N). We also compared
larval abundances across the 2 upwelling regions for 1 year. Most species were retained nearshore,
regardless of intra- and inter-annual variations in the intensity of upwelling. In both
upwelling regions, larvae of each species consistently occurred at different distances from the
shore. Further, there were no differences in nearshore larval abundance across upwelling regions
for all but 1 larval stage of 1 species. Thus, latitudinal variations in the intensity and persistence of
upwelling do not appear to affect larval survival, providing further evidence that nearshore processes
may be a primary determinant of larval delivery to the rocky intertidal across these regions.

Theme: Ecosystem approach to improve management of marine resources
Foci: Understand how climate influences ecosystem variability.