i
Sacramento River winter Chinook cohort reconstruction : analysis of ocean fishery impacts
-
2012
-
[PDF-643.48 KB]
Details:
-
Personal Author:
-
Corporate Authors:
-
NOAA Program & Office:
-
Description:"Endangered Sacramento River winter Chinook salmon (SRWC) are harvested incidentally in ocean salmon fisheries that target more abundant stocks. To evaluate the effect of these fisheries, cohort reconstructions were performed for ten broods (1998-2007) of hatchery-origin SRWC using coded-wire-tag data. Results indicate that the majority of ocean fishery impacts were attributed to recreational fisheries south of Point Arena, California. For complete broods 1998-2005, the number of potential SRWC spawners was reduced by an estimated 11 to 28 percent owing to ocean salmon fisheries. The spawner reduction rate for incomplete broods 2006 and 2007 will likely be zero, or nearly zero, due to the closure of most ocean salmon fisheries for 2008 and 2009 in California. SRWC were predominantly caught as age-3, consistent with estimates of high (> 85 percent) age-3 maturation rates that resulted in low ocean abundance of age-4 and older fish. Spawner reduction rates and ocean fishery age-3 impact rates were largely concordant, and no temporal trend in these rates was observed over the range of years considered here, with the exception of recent years with widespread fisheries closures. In contrast to the relative consistency in ocean fishery effects on the SRWC population, the composite (hatchery and natural-origin) SRWC stock has experienced recent increases, and subsequent declines, in spawner escapement. These recent trends in spawner escapement cannot readily be explained by the exploitation history estimated during the same time frame"--Abstract.
-
Content Notes:Michael R. O'Farrell, Michael S. Mohr, Allen M. Grover, William H. Satterthwaite.
"August 2012."
System requirements: Adobe Acrobat Reader.
Includes bibliographical references (pages 32-33).
-
Keywords:
-
Series:
-
Document Type:
-
Place as Subject:
-
Rights Information:Public Domain
-
Compliance:Library
-
Main Document Checksum:
-
Download URL:
-
File Type:
