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AHUYEMAR – Development of innovative methodologies to prevent the interaction of marine mammals with purse seine nets during fishing activity

Pleamar program

Description:

The project aims to eliminate or reduce the bycatch of marine mammal species, mainly dolphins, by purse seine fisheries in the Northwest Cantabrian National Fishing Ground. To this end, the characterization of the species with which the fishing gear has the most interaction and their behavior patterns will be carried out; A protocol of action will be designed in the presence of dolphins and the most appropriate technology will be selected to scare them away. Towards the middle of the development of the project, the design and execution of an experimental observation campaign during fishing activity will begin to determine the effectiveness of the new methodology established and scaring equipment. Depending on the results obtained, the proposed action protocol will be adapted and implemented.

See the project.

Line of action:

Marine ecosystems

Status:

Finalizado

Execution date:

2019

General Objective:

To prevent the accidental capture of marine mammal species (dolphins, porpoises, etc.) that are caught in purse seine fisheries carried out in the Cantabrian National Fishing Ground NW.

Specific objectives:

1. Identify the species of marine mammals with which the fishing gear has the greatest interaction and their pattern of behavior

2. Select the most appropriate technology to drive away the virus, with the consequent experimental campaign and processing of the data collected.

The execution of Ahuyemar has made it possible to collect information on the interaction of cetaceans with the purse seine fishery of the North Atlantic fishing ground. The extraction of historical data, between 2009 and 2011 by CEMMA personnel, in addition to the data provided by 450 purse seine crew members and 53 interviews conducted with sailors on observation and incidents that affect marine mammals around purse seine gear, have been relevant since they allowed to make a report on characterization and behavior patterns in relation to purse seine that included the following conclusions:

Considering the entire fleet (253 vessels in 2020), on average there is an accidental capture of cetaceans every day in the waters of the Cantabrian and Northwest fishing grounds.

  • 96.4% of the sailors interviewed stated that it is common to observe cetaceans during fishing days. Only 31.4% of sailors correctly identified cetacean species. The two species most frequently observed were the common dolphin and the bottlenose dolphin (52%).
  • Most sailors (59.4%) considered cetaceans to be harmful to their activity while 23% considered them beneficial. 45.3% stated that, in reality, the negative impact of cetaceans on their activity was not really significant, and therefore no measures need to be applied. 28.2% admitted that the negative impact existed, with the breakage of nets being the main damage to the purse seine fleet, but they were resigned to the situation, indicating that the damage that cetaceans cause to the purse seine fleet had always been present and they considered that it was not possible to reach any type of solution.
  • 70.2% of sailors stated that cetaceans are accidentally caught. The two species of cetaceans most involved in the accidental captures that occur in the purse seine fleet in waters of the Cantabrian and Northwest fishing grounds are the common dolphin (77.2%), and the bottlenose dolphin (18.5%).
  • 48.9% of the sailors interviewed indicated that, once the cast is over, cetaceans usually survive capture and leave the purse seine alive.

Regarding the embarkations to test the pinguers, the scheduled days of embarkation were fulfilled, 14 whale sightings were made, of which ten (71.4%) were systematic sightings and four (28.6%), opportunistic. Of these 14 sightings, 12 (85.7%) were made by the scientific observer and two (14.3%) by the skipper of the ship CHA-VEIGA. In the case of the 12 sightings made by the scientific observer, 10 corresponded to the common dolphin, 1 to the bottlenose dolphin and 1 sighting to an unidentified dolphin.

ARVI reported that it was not possible to verify the effectiveness of marine mammal dispersal systems, due to the reduced presence and absence of interaction of cetaceans with the purse seine vessel. In this way, in order to be able to record cetacean-fishery interaction events and evaluate and validate these devices, it would be necessary to significantly increase the sampling effort, have a team of multiple observers, several participating purse seine vessels and longer sampling periods.

Finally, a report was made on dispersal methods and a protocol of good practices in the presence and/or accidental capture was delivered, aimed at the crew of the purse seine fleet, since prevention and the performance of correct maneuvers during fishing can reduce interaction and minimize cetacean mortality for this reason.

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AHUYEMAR – Development of innovative methodologies to prevent the interaction of marine mammals with purse seine nets during fishing activity