Fishery-induced Changes in the Population Structure of Pink Shrimp Pandalus jordani

Identification Information

Citation

Originator: Hannah, R.W. and S.A. Jones

Publish Date: 1991

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: The trawl fishery for ocean pink shrimp (Pandalus jordani Rathbun) has increased dramatically since the early 1970s. Catch and effort statistics and catch sampling data from 1968-88 were analyzed to evaluate changes in the shrimp population structure. Carapace length at age one and two have increased significantly since 1978, concurrent with a reduction in fishery catch per unit effort, strongly indicating density- dependent growth. The seasonal pattern of growth provides further evidence for density-dependent growth. The number of age three shrimp in the catch has declined markedly since 1978, while age one shrimp have increased from 30.6% of the catch to 69.2%. The percentage of age one shrimp maturing as females has increased to 30-50% in some years, while the overall percentage of males shows no trend. The changes in growth, and age and sex composition of the catch are attributed in part to the impact of the trawl fishery, which is currently continuing to intensify. Density-dependent growth, and the ability to accelerate the sex change process make pink shrimp resistant to over-harvest. However, at some exploitation level the reduction of the age 1 spawning stock should begin to reduce subsequent recruitment. Recent strong year classes indicate that the fishery probably has not reached that level of exploitation.

Purpose: Manuscript accepted 24 August 1990. Fishery Bulletin. U.S. 89:41-51 (1991).

Time Period of Content: 1968-1988

Geographic Extent: Oregon Coast

Status: Final

Use Constraints:

Format: PDF file

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Attributes Description: Not yet described

Bibliography Information

Field Name	Value
Biblio ID	8512
Year	1990
Publisher
Request Type	Report
Location	Salem HQ
Date Created	1990
Date Cataloged	8/3/05
Date Published	1991
Type	stp spine
Pages	pp41-51
Volume
Status	2
Descriptor	pink shrimp; population
Date Entered	2005-08-03 16:33:13
Location In Clackamas Library	Wildllife/marine life
Author	Robert W Hannah; Stephen A Jones
Duplicates	0
Number Remaining After Requests	1
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Is a physical copy maintained for reference at Headquarters? Yes