Evaluation of Methods Used to Estimate Geographic Stock Area for Ocean Shrimp (Pandalus Jordani) from Logbook Data Information Reports 97-6

Identification Information

Citation

Originator: Robert W. Hannah ODFW

Publish Date: Aug 1997

Online Link: None

BPA Project #:

Contact Information

Agency: Oregon Department of Fish and Wildlife

Name: Cedric Cooney

Job Position: Natural Resources Data and Systems Manager

Telephone: 503-947-6094

E-Mail Address: Cedric.X.Cooney@odfw.oregon.gov

Description

Abstract: Prior analysis of logbook data from the ocean shrimp (Pandalus jordani) trawl fishery has shown that the geographic area in which commercial concentrations of shrimp are found varies substantially between years roughly in proportion to stock abundance (Hannah 1995). This variation in stock area has important implications for assessment of the ocean shrimp stock for example, it indicates that catch per unit effort (CPUE), as it's commonly calculated, will not accurately index abundance (Beverton and Holt 1957, Winters and Wheeler 1985, MacCall 1990 and others). It also suggests that variation in stock area should be accounted fur in developing accurate spawning stock and recruitment indices for ocean shrimp (Hannah 1993). The variation observed in the stock area of ocean shrimp probably stems from changes in the distribution of newly recruited year classes. These distributional changes may result from variation in larval transport or in the geographic pattern of larval survival (Hannah 1993, Hannah 1995). My previous estimates of stock area for ocean shrimp relied on two key assumptions about the nature of the shrimp fishery (Hannah 1995). I assumed that the fishery was directed strongly enough at age one shrimp that the geographic distribution of successful catches would reflect the geographic distribution of these shrimp. This assumption was based on the age composition data presented by Hannah and Jones (1991) showing that age 1 shrimp dominated the trawl catch after about 1979. The second assumption was that variation in the rate at which logbook data were sampled would not create significant errors in the estimates of stock area. Sampling rates in the earlier study, based on the percentage of the total catch included in the logbook data sets ranged from 25% to 47% (Hannah 1995). In this study, I critically evaluated these two assumptions about the shrimp fishery and then tried to develop a standard "best" method for estimating stock area from logbook data for ocean shrimp.

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Geographic Extent: Oregon

Status: Final

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Format: PDF File

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Bibliography Information

Field Name	Value
Biblio ID	5667
Year	1997
Publisher
Request Type	Information Report
Location	Salem HQ
Date Created	Aug 1997
Date Cataloged	6/22/05
Date Published	Aug 1997
Type	info repo
Pages	17 pp
Volume	97-6
Status	2
Descriptor	Shrimp; Logbook data; Oregon
Date Entered	2005-06-22 00:00:00
Location In Clackamas Library	S wall, yellow info reports 2nd row
Author	Robert W Hannah
Duplicates	0
Number Remaining After Requests	5
Presumed All Distributed
Back Room Duplicates
Author	Robert W. Hannah
Risk
Species
Disposition Of Requests	StreamNet Library: Request filled

Is a physical copy maintained for reference at Headquarters? Yes