Thumbnail Image

Bycatches and non-tuna catches in the tropical tuna purse seine fisheries of the world

Year of publication 2013

Pages 249

Author Fisheries and Aquaculture Management Division

Product type Book (series)

ISBN 9789251072417

Series title FAO Fisheries and Aquaculture Technical Papers

Series number 2070-7010 - T568

Edition 1

Synopsis (short abstract) This report provides a review of our knowledge of the bycatches, defined as discarded dead, from the tropical tuna purse seine fisheries of the world. The major fishing grounds involved (eastern and western Pacific, eastern Atlantic, and western Indian Oceans) share the gear, the ways of fishing, and the structure of the pelagic communities. Because of that, the species taken in association with tuna schools tend to be the same in all regions. After describing the gear and fishing operations, it discusses the reasons why bycatches happen, and explores the options to mitigate them. The types of sets used to capture tunas and the detection methods used to locate the schools are a major factor to determine which are the catches and the bycatches. The main bycatches are tunas, sharks and rays, pelagic bony fishes, billfishes, and sea turtles. The total discard amount to one to five percent of the total tonnage captured, and tunas of the species targeted amount to over 90–95°percent of thos e bycatches. The silky shark is the most common shark species by far, followed by the oceanic whitetip sharks. Marlins and sailfishes are also taken but in reduced numbers. Olive ridley sea turtles are the most common turtle captured, but the majority of them are released alive and unharmed. Rainbow runners, mahi-mahis, wahoos and amberjack yellowtail are the major pelagic bony fishes taken with the tunas. They are being retained in increasing numbers for utilization. Besides discussing problem s of estimation, the report presents most of the ideas proposed or in different stages of testing, to mitigate those bycatches, including ways to avoid the captures, or to release the individuals from the net or from the deck. Finally, the known or potential ecological impacts of the rapidly increasing fishery on fish aggregating devices (FADs) are reviewed, emphasizing some of the uncertainties that still prevail.

Cite this content as:

Hall, M.; Roman, M. 2013. Bycatch and non-tuna catch in the tropical tuna purse seine fisheries of the world. FAO Fisheries and Aquaculture Technical Paper No. 568. Rome, FAO. 249 pp.

Language English

Also available in:
No results found.

Related items

Showing items related by metadata.

  • Thumbnail Image
    Book (series)
    Overview of mitigation measures to reduce the incidental catch of vulnerable species in fisheries 2021
    Also available in:
    No results found.
    Potentially harmful contact between fisheries and marine vulnerable species represents a global conservation issue and efforts to mitigate the negative repercussions of these interactions belong in strategies for ensuring the sustainability of fisheries. This literature review offers a survey of mitigation measures and techniques that have been developed and tested around the world, aiming to address both the incidental catch of highly mobile species – specifically, cetaceans, seabirds, sharks and rays, and sea turtles – and depredation caused by dolphins. Based on research detailed in over 300 documents, including peer-reviewed publications, reports from international organizations and papers available on the internet, most of the mitigation techniques illustrated are still under development, with only a few already adopted through legislation. The selected mitigation measures are grouped by main types of fishing gear – gillnets and trammel nets, longlines and lines, trawls, purse seines, traps and pots – and further subdivided according to which of the four main groups of vulnerable species – cetaceans, seabirds, sharks and rays, or sea turtles – they are designed to protect. Preventive and curative approaches covering both technical measures (gear modifications, strategies, as well as acoustic, visual, magnetic and chemosensory deterrents) and management measures are described.
  • Thumbnail Image
    Book (series)
    Monitoring incidental catch of vulnerable species in the Mediterranean and the Black Sea: Methodology for data collection 2019
    Also available in:
    Bycatch – a term widely used to refer to the part of catch unintentionally captured during a fishing operation, in addition to target species, and consisting of discards and incidental catches of vulnerable species – is considered one of the most important threats to the profitability and sustainability of fisheries, as well as to the conservation of the marine environment and ecosystems. In the Mediterranean, studies on the incidental catch of vulnerable species cover only a small portion of the total fishing activity. In addition, there are several important knowledge gaps for many types of fishing gear, and several countries and/or subregions, as well as on temporal scales, and only a few measures are in place that address the protection of vulnerable species. Monitoring programmes and surveys on incidental catches, which follow a harmonized methodology allowing for results to be compared across subregions, are necessary to improve knowledge on the issue and to subsequently support the identification of potential mitigation methods and tools, and relevant management measures. This publication and the methodology contained herein aim to provide a framework for the development and implementation of an efficient, standardized data collection and monitoring system for all vulnerable species encountered in the Mediterranean and the Black Sea, namely elasmobranchs, marine mammals, seabirds, sea turtles, and macrobenthic invertebrates.
  • No Thumbnail Available
    Book (series)
    Status of Interactions of Pacific Tuna Fisheries in 1995
    Proceeding of the Second FAO Expert Consultation on Interactions of Pacific Tuna Fisheries Shimizu, Japan 23 to 31 January 1995
    1996
    Also available in:
    No results found.
    This publication includes forty papers and two abstracts of papers presented at the Second FAO Expert Consultation on Pacific Tuna Fisheries held in Shimizu, Japan, from 23 to 31 January 1995. The topics of the papers include: · reviews of tuna fisheries interactions and their research including methods for their study, · new methods for studying tuna fisheries interactions and examination of their applicability, · case studies on tuna fisheries interactions, · analyses of tuna fisheri es involved in interactions and their management, and · an overview of FAO’s project that co-organized and co-sponsored the Consultation. A supplement of an indexed bibliography of papers on tuna and billfish tagging, which was printed separately, is also included. The objectives of the Consultation were to: · review and integrate the outcome of the studies on tuna fisheries interactions, · summarize the extent of tuna fisheries interactions and unresolved research problems, and · fo rmulate guidelines for research on tuna fisheries interactions. The understanding of tuna fisheries interactions was enhanced significantly by recent studies. However, the Consultation noted that the number of quantified interactions is still small due primarily to difficulties associated with evaluating such interactions. The papers providing supporting information for the conclusions of the Consultation are presented in this publication. Interactions were found to vary in significance depend ing on the biological characteristics of the species involved, the sizes of fish caught, the local and stock-wide rates of exploitation, and the distance among fisheries. In many of the studies presented, the inadequacy of fisheries data was stressed. In addition, the lack of understanding of movements of the fish being studied was noted in several papers. General qualitative guidelines presented in several discussion papers stressed that specifically-designed studies be undertaken to adequately quantify interactions. Well-designed tagging experiments were thought to provide the most reliable information about interactions. Guidelines for the collection of data, biological and ecosystem research, modelling, and alternative methodologies for studying tuna fisheries interactions are also included.
Show more

Users also downloaded

Showing related downloaded files

No results found.