Non-Entangling & Biodegradable FADs Guide

ISSF’s Non-Entangling & Biodegradable FADs guide for tuna fishers, Regional Fisheries Management Organizations (RFMOs), governments, and vessel owners shows research-based best practices in Fish Aggregating Device (FAD) design — both to avoid bycatch and reduce marine pollution.

Four tuna RFMOs already require fleets in their regions that fish with FADs to use only non-entangling designs. Some RFMOs additionally encourage fleets to build those FADs with biodegradable materials. The guide, first published in 2012 and revised in 2019 to include the biodegradable recommendation, is available in several languages.

ISSF 2016-17: Mitigation of Silky Shark Bycatch in Tropical Tuna Purse Seine Fisheries

Date Added: December 12, 2016
Downloaded: 425 times
Tags: Bycatch Mitigation, Moreno, Purse Seine, Restrepo, Sharks, Tuna
Authors: Dagorn, Moreno, Restrepo
Language: English
Author(s): Victor Restrepo, Laurent Dagorn & Gala Moreno
report_type: Technical Report

Description

Pelagic sharks are not targeted by tropical tuna purse seine fisheries, but they are caught incidentally, especially around floating objects like FADs. The shark bycatch-to-tuna catch ratio in purse seine fisheries is quite small, on average, less than 0.5% in weight. Over 90% of that bycatch is composed of silky sharks, Carcharhinus falciformis. Because of their low reproductive rates and other life history characteristics, silky sharks are a vulnerable species.

The contribution of purse seining to the total catch of this species varies by ocean: from 4% in the Indian and Eastern Pacific Oceans, to about 25% in the Western and Central Pacific Ocean regions. The global magnitude of catch of the purse seine fishery is quite large, so reducing the mortality caused by these fisheries can contribute to global conservation efforts. This document summarizes mitigation techniques that can be used in this fishery.