Fishing yields and size structures of Patagonian toothfish (Dissostichus eleginoides) caught with pots and long-lines off far southern Chile

Abstract

Herein, we compare information taken from the Patagonian toothfish ( Dissostichus eleginoides ) fishery operations carried out off the far southern coast of Chile (47°00’S-57°00’S) using pots (pots) and longlines. In January 2006 and from June to October 2006, 167 fishing hauls were done, 119 using long-lines and 48 using pots. The total Patagonian toothfish catch was 60.9 tons, of which 81.2% were caught with long-lines and 18.8% with pots. On average, 5,395 hooks and 147 pots were set per haul, with average yields of 0.08 kg hook -1 and 1.43 kg pot -1 . The average depth for setting the gear was 1,581 m (long-lines) and 1,318 m (pots). Significant differences were found between these two types of gear, as well as between the time of setting and the time of retrieval. Greater fishing yields were obtained from the long-line fishery operations, with significant differences between the gear types in terms of the catch per haul (kg haul -1 ) and the catch per length of the specimens retained (kg 1000 m -1 ). On average, the individuals caught with pots (110.8 cm total length) were larger than those caught with long-lines (105.1 cm total length). Nonetheless, no significant differences were recorded for the size structures. In terms of interactions with birds, during setting, no birds were observed at the trapping operations, whereas a few specimens (≤ 10 birds) were seen during only 2.5% of the long-line operations. During retrieval, birds were observed during 34.9% of the hauls with pots and 62.8% of the longline operations. The presence of mammals around the fishery operations during setting and retrieval was similar for both types of gear.