Inverse regional responses to climate change and fishing intensity by the recreational rockfish (Sebastes spp.) fishery in California.. Bennett, William A.; Roinestad, Kimy; Rogers-Bennett, Laura; Kaufman, Les; Wilson-Vandenberg, Deb; Heneman, Burr.
NRC Research Press Canadian Journal of Fisheries & Aquatic Sciences:
2004
Notes
The interactive effects of ocean climate and fishing pressure on nearshore rockfishes (Sebastes spp.) were examined using historical commercial passenger fishing vessel catch records from California. Principal component analysis was used to characterize the dominant patterns in catch per unit effort (CPUE) over time (1957–1999) and space (10' latitude × 10' longitude blocks). Ocean climate explained 60% of the variation in CPUE and revealed opposite responses in northern and southern California. In warm El Niño years, CPUE was 4.2 times higher in the north and 1.8 times lower in the south. CPUE responded similarly to low-frequency climate shifts by increasing in the north and decreasing in the south after 1976–1977. Four geographic regions responded as discrete units to environmental forcing and fishing intensity: North, Central, South, and Channel Islands. Over time, annual fish landings declined sharply in the South, with fishing effort remaining stationary and high relative to that in the other regions. In the North, landings and fishing effort remained tightly coupled, with effort an order of magnitude lower than in the South. These findings support a management strategy for nearshore rockfishes in California based on regional responses to ocean climate and fishing intensity. Nous avons examiné les effets interactifs du climat océanique et de la pression de la pêche sur les sébastes (Sebastes spp.) de la région côtière en étudiant des données de pêche des années antérieures provenant des bateaux à passagers de pêche commerciale (« Commercial Passenger Fishing Vessels ») de Californie. Une analyse des composantes principales a servi à identifier les principales tendances des captures par unité d'effort (CPUE) dans le temps (1957–1999) et l'espace (des surfaces de 10' latitude × 10' longitude).
Surplus production, variability, and climate change in the great sardine and anchovy fisheries. Jacobson, L. D.; De Oliveira, J. A. A.; Barange, M.; Cisneros-Mata, M. A.; Felix-Uraga, R.; Hunter, J. R.; Kim, J. Y.; Matsuura, Y.; Niquen, M.; Porteiro, C.; Rothschild, B.; Sanchez, R. P.; Serra, R.; Uriarte, A.; Wada, T..
Canadian Journal of Fisheries & Aquatic Sciences:
2001
Notes
We used fishery and survey data to calculate annual surplus production (ASP) and instantaneous surplus production rates (ISPR) for eight anchovy and nine sardine stocks. In addition, we calculated ASP per unit spawning area for six anchovy and six sardine stocks. Median ASP was highest for stocks with highest median biomass (mostly anchovies), and ASP was typically about 16% of stock biomass. ASP was often negative, more frequently for anchovies (36% of years) than for sardines (17% of years). ISPR was less variable for sardines and autocorrelated for longer-lived stocks (mostly sardines). Strong biomass increases tended to be preceded by short, abrupt increases in ISPR, and declines were pronounced when catches exceeded ASP for 5 years or more. The longest "runs" of positive and negative production were 21 and 4 years for sardine off Japan, 10 and 3 years for sardine off California, 8 and 2 years for anchovy off Peru, and 4 and 3 years for anchovy off California. ISPR is more sensitive to environmental changes than catch, biomass, or ASP and appear to be better for identifying environmentally induced regime shifts. Long time series show evidence of density-dependent effects on ASP in anchovies and sardines, but environmentally induced variation appears to dominate.
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