Fluctuations of year-class strength in petrale sole (Eopsetta jordani) and their relation to environmental factors Public Deposited

http://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/nv9355709

Descriptions

Attribute NameValues
Creator
Abstract or Summary
  • The effects of potential parental egg production and environmental factors on year-class strength (YCS) of petrale sole (Eopsetta jordani) were investigated in two areas off Oregon and Washington (Pacific States Marine Fisheries Commission areas 2B: 42° 50'N - 44°18'N, and 3A: 45° 46'N - 47°20'N). Indices of YCS based on Summed-CPUE (summed catch rates of females for ages 6 + 7) and cohort analysis (numbers of females attaining age-6) tended to be significantly correlated within and between areas 2B and 3A (r ≥ 0.45, P ≤ 0.06). Since cohort analyses were deemed more reliable YCS indices than Summed-CPUE indices, only cohort analyses were used to determine the role of potential parental egg production and environmental factors on YCS variations. Large YCS fluctuations were evident from 1958 to 1977. Year-classes born from 1962 to 1965 and from 1973 to 1977 were intermediate to weak cohorts in areas 2B and 3A. In both areas, estimates of commercial catch rates suggested a substantial decline of abundance from the middle 1970's to the middle 1980's. The fact that the large decrease of YCS for cohorts born from 1973 to 1977 was not preceded by a decline in commercial catch rates, and that spawner-recruit relations were not detected, suggested that density-independent factors were more important than parental-stock size during the initial decrease of YCS in the 1970's and the subsequent decline of catch rates in the late 1970's. For cohorts born from 1958 to 1977, a regression model based on indices of offshore Ekman transport from January to March, and alongshore transport from December to February accounted for nearly 55% of the YCS variations in area 2B. For area 3A, sea surface temperature from December to February along with the previous environmental factors explained about 65% of the YCS variation. In a lower extent, winter salinity variations due to the Columbia River also appeared to be related to recruitment strength in area 3A. These findings suggested that YCS fluctuations of petrale sole from 1958 to 1977 may have been primarily forced by winter and early spring oceanographic conditions affecting distribution and/or survival of eggs and early larval stages.
Resource Type
Date Available
Date Issued
Degree Level
Degree Name
Degree Field
Degree Grantor
Commencement Year
Advisor
Academic Affiliation
Non-Academic Affiliation
Subject
Rights Statement
Language
Digitization Specifications
  • Master files scanned at 600 ppi (256 Grayscale) using Capture Perfect 3.0 on a Canon DR-9080C in TIF format. PDF derivative scanned at 300 ppi (256 B&W), using Capture Perfect 3.0, on a Canon DR-9080C. CVista PdfCompressor 4.0 was used for pdf compression and textual OCR.
Replaces
Additional Information
  • description.provenance : Approved for entry into archive by Linda Kathman(linda.kathman@oregonstate.edu) on 2009-01-12T19:36:56Z (GMT) No. of bitstreams: 1 Castillo_Gonzalo C._1992.pdf: 671112 bytes, checksum: cf23e509ed1ae7ef9edf2cab3e37b221 (MD5)
  • description.provenance : Made available in DSpace on 2009-01-12T19:36:58Z (GMT). No. of bitstreams: 1 Castillo_Gonzalo C._1992.pdf: 671112 bytes, checksum: cf23e509ed1ae7ef9edf2cab3e37b221 (MD5)
  • description.provenance : Submitted by Patricia Black (patricia.black@oregonstate.edu) on 2009-01-12T17:44:33Z No. of bitstreams: 1 Castillo_Gonzalo C._1992.pdf: 671112 bytes, checksum: cf23e509ed1ae7ef9edf2cab3e37b221 (MD5)
  • description.provenance : Approved for entry into archive by Linda Kathman(linda.kathman@oregonstate.edu) on 2009-01-12T19:35:34Z (GMT) No. of bitstreams: 1 Castillo_Gonzalo C._1992.pdf: 671112 bytes, checksum: cf23e509ed1ae7ef9edf2cab3e37b221 (MD5)

Relationships

Parents:

This work has no parents.

Last modified

Downloadable Content

Download PDF

Items