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Use of Egg Presence–Absence to Derive Probability‐Based Management Criteria for Upper Chesapeake Bay Striped Bass
Author(s) -
Uphoff James H.
Publication year - 1997
Publication title -
north american journal of fisheries management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.587
H-Index - 72
eISSN - 1548-8675
pISSN - 0275-5947
DOI - 10.1577/1548-8675(1997)017<0663:uoepat>2.3.co;2
Subject(s) - chesapeake bay , morone saxatilis , fishery , bass (fish) , zoology , bay , fishing , coefficient of variation , stock (firearms) , biology , mathematics , estuary , oceanography , geography , statistics , geology , archaeology
I used egg presence–absence for striped bass Morone saxatilis from five Maryland spawning areas during 1955–1992 to develop criteria for assessing whether upper Chesapeake Bay spawning stock was at a level providing high and stable recruitment or below a level where recruitment declines appreciably. Strong year‐classes did not occur when the proportion of tows with eggs ( E p ) fell below 0.60. and the probability of a poor year‐class occurring increased greatly as E p fell below 0.80. Mean recruitment increased and coefficient of variation decreased as E p rose from 0.40 to 0.80. Highest mean recruitment and lowest coefficient of variation occurred when E p was at or above 0.80. A probability‐based assessment of upper Chesapeake Bay spawningstock recovery indicated a high risk that spawning‐stock status did not recover in 1994 and a low risk in 1995. Upper Chesapeake Bay E p , grew during the late 1950s, was highest and stable during the 1960s, decreased through the 1970s to its nadir in the mid‐1980s, and then grew quickly through the early 1990s. Stable E p coincided with annual instantaneous fishing mortality rates ( F ) of 0.50–0.60; decreasing E p occurred when F exceeded 0.75, and increasing E p occurred when F was less than 0.25.