A Method for Forecasting the Timing of Ripeness in Pacific Herring (Clupea harengus pallasi) Females
| Autor: | D. M. Ware, R. W. Tanasichuk |
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| Rok vydání: | 1990 |
| Předmět: | |
| Zdroj: | Canadian Journal of Fisheries and Aquatic Sciences. 47:2375-2379 |
| ISSN: | 1205-7533 0706-652X |
| DOI: | 10.1139/f90-264 |
| Popis: | A procedure was developed to forecast when Pacific herring females become ripe. The method uses a size-independent quantitative measure of maturity (D), which is the difference between the observed GSI (gonosomatic index) and the GSI expected at full maturity (Q) for a given body weight. We use D to segregate fish within samples, and then to split the samples into maturity groups. These groups often reflect discrete spawning waves. We regress mean D values for samples within a maturity group against date of collection to calculate when the observed GSI will equal Q, that is, when those females will be ripe. Analysis of data for 14 maturity groups indicates that the date of ripeness can be forecast with an average accuracy of 0.5 d, 5–6 d before it occurs. This procedure should be useful to fishery managers concerned with staging fisheries on mature fish and to investigators who need to know when a spawning stock reaches full maturity. |
| Databáze: | OpenAIRE |
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