Abstract
Commercial fisheries data, collected as part of an observer programme and covering the period 1997-2014, were utilized in order to define key reproductive traits and spawning dynamics of the Patagonian toothfish Dissostichus eleginoides at South Georgia. Multi-year spawning site fidelity of D. eleginoides was revealed through the identification of previously unknown spawning hotspots. Timing of female spawning was shown to have shifted later, leading to a shorter spawning duration. A decrease in length and mass of female and male spawning fish and a reduced number of large spawning fish was found, evidence of a change in size structure of spawning D. eleginoides. During the study period fewer later maturity stage females (including spawning stage) were observed in conjunction with increased proportions of early stage female D. eleginoides. The findings are discussed in the context of reproductive success, with consideration of the possible effects such spawning characteristics and behaviours may have on egg and larval survival. This work presents the first long-term assessment of D. eleginoides spawning dynamics at South Georgia and provides valuable knowledge for both the ecology of the species and for future fisheries management of this commercially important species.
Original language | English |
---|---|
Pages (from-to) | 278-301 |
Number of pages | 24 |
Journal | Journal of Fish Biology |
Volume | 91 |
Issue number | 1 |
Early online date | 9 Jul 2017 |
DOIs | |
Publication status | Published - Jul 2017 |
Bibliographical note
This study was possible thanks to the generous support and funding from Georgia Seafoods Ltd. The work was carried out in association with project partners: the Government of South Georgia & the South Sandwich Islands, and the British Antarctic Survey. The authors thank the captains, crew and on-board observers involved in longline fishing and data collection at sub-area 48·3 for the period 1997–2014. Thanks are extended to I. Marengo for advising on spatial statistics; M. Soeffker for early discussions on toothfish tagging work at South Georgia which highlighted potential spawning grounds; and also to M. Belchier and P. Brewin whose comments helped improve the manuscript.Keywords
- Dissostichus eleginoides
- fisheries management
- reproduction
- Shag rocks
- spawning
- spawning dynamics