Long-term trends of Southern California's kelp and barred sand bass populations: A fishery-independent assessment

TitleLong-term trends of Southern California's kelp and barred sand bass populations: A fishery-independent assessment
Publication TypeJournal Article
Year of Publication2014
AuthorsMiller E.F, Erisman B
JournalCalifornia Cooperative Oceanic Fisheries Investigations Reports
Volume55
Pagination119-127
Date Published2014/12
Type of ArticleArticle
ISBN Number0575-3317
Accession NumberWOS:000346192400007
Keywordsclimate; Cod; evolutionary time scales; management; north-sea; paralabrax-nebulifer; pressures; recreational fisheries; recruitment; sustainable fisheries
Abstract

Power plant entrapment monitoring data provided insights on conditions leading up to and contributing to previously documented collapses of the southern California kelp bass (Paralabrax clathratus) and barred sand bass (P. nebulifer) fisheries. Individuals from all size classes from both species were taken over time at three sites spanning nearly 100 km along the southern California coast. Size class abundance peaked in the 200 to 250 mm SL size classes, or near the minimum size limit for the two southern California fisheries (250 mm SL). Annual modal lengths remained relatively static in P. clathratus, but significantly declined in P. nebulifer with a strong downsizing after 1993. Abundance indices for each species significantly declined over nearly four decades of monitoring: 97% in P. clathratus and 86% in P. nebulifer. Evidence suggests sporadic larval settlement by each species led to occasionally abundant year classes, such as 1982 (P. clathratus) and 1994 (P. nebulifer), interspersed with several consecutive years of comparably minimal settlement. No significant correlations with common climate indices including the Multivariate ENSO Index, Pacific Decadal Oscillation, and North Pacific Gyre Oscillation were detected for either species' year-class abundance index. The P. nebulifer year-class abundance index did significantly correlate, albeit weakly, with annual mean sea surface temperature. These results signify that, at this time, no environmental proxy for either species larval settlement exists.

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