Abstract
Movement and re-aggregation after fishing of a stock may have a major impact on estimates of abundance and stock assessment parameters such as natural mortality. The propensity of blacklip abalone (Haliotis rubra Leach) to re-aggregate after fishing was studied using a combination of in situ tagging with fine-scale mapping of two distinctly different abalone populations. Controlled fishing of each population was conducted to test the hypothesis that removal of abalone by fishing stimulates movements that result in re-aggregation. Declines in abundance due to fishing were evident but less than those expected had no recovery occurred. Changes in the fine-scale spatial distribution of abalone suggested that re-aggregation occurred through a series of contiguous displacements. Smaller emerging abalone did not appear to be the prime source for this re-aggregation. These results undermine the utility of change-in-ratio and catch-per-unit-effort methods of abundance estimation. They also highlight the need to develop methods of abundance estimation that accommodate the impact of aggregating behavior on blacklip abalone populations.
Original language | English |
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Pages (from-to) | 771-779 |
Number of pages | 9 |
Journal | Journal of Shellfish Research |
Volume | 20 |
Issue number | 2 |
Publication status | Published - 2001 |
Externally published | Yes |
Keywords
- Abalone
- Aggregation
- Haliotis rubra
- Movement