Estimating Dungeness crab (Cancer magister) abundance: Crab pots and dive transects compared
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- More information: Fishery Bulletin: Volume 102, Issue 3
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Abstract
Dungeness crabs (Cancer magister) were sampled with commercial pots and counted by scuba divers on benthic transects at eight sites near Glacier Bay, Alaska. Catch per unit of effort (CPUE) from pots was compared to the density estimates from dives to evaluate the bias and power of the two techniques. Yearly sampling was conducted in two seasons: April and September, from 1992 to 2000. Male CPUE estimates from pots were significantly lower in April than in the following September; a step-wise regression demonstrated that season accounted for more of the variation in male CPUE than did temperature. In both April and September, pot sampling was significantly biased against females. When females were categorized as ovigerous and nonovigerous, it was clear that ovigerous females accounted for the majority of the bias because pots were not biased against nonovigerous females. We compared the power of pots and dive transects in detecting trends in populations and found that pots had much higher power than dive transects. Despite their low power, the dive transects were very useful for detecting bias in our pot sampling and in identifying the optimal times of year to sample so that pot bias could be avoided.
Study Area
Publication type | Article |
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Publication Subtype | Journal Article |
Title | Estimating Dungeness crab (Cancer magister) abundance: Crab pots and dive transects compared |
Series title | Fishery Bulletin |
Volume | 102 |
Issue | 3 |
Year Published | 2004 |
Language | English |
Publisher | NOAA National Marine Fisheries Service |
Contributing office(s) | Alaska Science Center |
Description | 10 p. |
First page | 488 |
Last page | 497 |
Country | United States |
State | Alaska |
Other Geospatial | Glacier Bay |
Google Analytic Metrics | Metrics page |