Age and growth of redeye round herring Etrumeus whiteheadi off the South African coast |
| |
| Authors: | Y Geja MD Durholtz CL Moloney |
| |
| Affiliation: | 1. Branch Fisheries Management, Department of Agriculture, Forestry and Fisheries, Cape Town, South Africa;2. Zoology Department and Marine Research Institute, University of Cape Town, Cape Town, South Africa;3. Zoology Department and Marine Research Institute, University of Cape Town, Cape Town, South Africa |
| |
| Abstract: | Ages of redeye round herring Etrumeus whiteheadi were estimated with associated errors and used to infer life-history information, such as age composition, age-at-maturity and instantaneous mortality rate. Samples were collected in November 2005 during a research survey aimed at estimating the biomass of spawning pelagic fish off South Africa’s west and south coasts. Replicate age estimates obtained from sagittal otoliths were collected with slight bias and relatively high precision. A von Bertalanffy model describing growth of the combined sexes, including juveniles, was Lt = 20.41(1 ? e?0.41(t ? 1.92)). Kimura’s likelihood ratio test revealed no statistically significant differences between growth parameters of males and females. Results suggested that otolith length is a better predictor of age than otolith weight. Maturity estimates for E. whiteheadi were similar to those previously documented. |
| |
| Keywords: | age estimates annuli otoliths precision |
|
|
