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Oceanographic influences on the distribution and relative abundance of market squid paralarvae ( Doryteuthis opalescens ) off the Southern and Central California coast
Author(s) -
Van Noord Joel E.,
Dorval Emmanis
Publication year - 2017
Publication title -
marine ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.668
H-Index - 58
eISSN - 1439-0485
pISSN - 0173-9565
DOI - 10.1111/maec.12433
Subject(s) - oceanography , bay , squid , environmental science , zooplankton , population , sea surface temperature , abundance (ecology) , fishery , population density , food web , ecosystem , ecology , biology , geology , demography , sociology
Abstract Market squid ( Doryteuthis opalescens ) are ecologically and economically important to the California Current Ecosystem, but populations undergo dramatic fluctuations that greatly affect food web dynamics and fishing communities. These population fluctuations are broadly attributed to 5–7‐years trends that can affect the oceanography across 1,000 km areas; however, monthly patterns over kilometer scales remain elusive. To investigate the population dynamics of market squid, we analysed the density and distribution of paralarvae in coastal waters from San Diego to Half Moon Bay, California, from 2011 to 2016. Warming local ocean conditions and a strong El Niño event drove a dramatic decline in relative paralarval abundance during the study period. Paralarval abundance was high during cool and productive La Niña conditions from 2011 to 2013, and extraordinarily low during warm and eutrophic El Niño conditions from 2015 to 2016 over the traditional spawning grounds in Southern and Central California. Market squid spawned earlier in the season and shifted northward during the transition from cool to warm ocean conditions. We used a general additive model to assess the variability in paralarval density and found that sea surface temperature ( SST ), zooplankton displacement volume, the log of surface chlorophyll‐ a , and spatial and temporal predictor variables explained >40% of the deviance (adjusted r 2 of .29). Greatest paralarval densities were associated with cool SST , moderate zooplankton concentrations and low chlorophyll‐ a concentrations. In this paper we explore yearly and monthly trends in nearshore spawning for an economically important squid species and identify the major environmental influences that control their population variability.