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There are three major areas of concern when it comes to sharks: observed bycatch, unobserved mortality due to entanglement in fishing gear, and difficulties in monitoring the practice of shark finning — and enforcing anti-finning measures.

Shark Bycatch

Sharks are caught in purse-seine, longline, gillnet, and other tuna fisheries, usually as bycatch.

Because of their low reproductive rates and other life-history characteristics, many species of sharks are vulnerable to fishing. 

Common Shark Species in Tuna Fisheries

  • Silky shark (Carcharhinus falciformis)
  • Oceanic whitetip shark (Carcharhinus longimanus)
  • Shortfin mako shark (Isurus oxyrinchus)
  • Blue shark (Prionace glauca)
  • Common thresher shark (Alopias vulpinus)
  • Pelagic thresher shark (Alopias pelagicus)
  • Bigeye thresher shark (Alopias superciliosus)


Anti-Shark-Finning Measures

Some vessels intentionally catch sharks to harvest their fins, which are valuable in certain markets. Shark finning threatens shark populations and violates the U.N. FAO Code of Conduct for Responsible Fisheries and IPOA-Sharks.

Our conservation measures 3.1(a), 3.1(b), and 3.1(c) ask ISSF participating companies to take certain steps to help prevent shark finning in the seafood industry.

Bycatch Prevention Strategies

Fishers can take steps before and after the tuna catch to reduce unintentional catches of silky sharks by up to 62%. We outline shark bycatch-mitigation techniques in scientific reports and skippers guidebooks. 

For shark bycatch rates by ocean, see our “Tropical Purse Seine Fisheries Bycatch” infographic series.

Bycatch Handling & Release Techniques

In ISSF guidebooks, infographics, posters, and scientific reports, we publish best practices that purse-seine fishers can follow onboard to safely release live sharks from the deck. We also have compiled shark identification resources by ocean.

We also report on collaborative workshops with fishers to discuss new equipment and handling techniques for releasing accidentally caught sharks and other species.

FAD Design & Management

Our Non-Entangling & Biodegradable FADs Guide for fishers illustrates how to build FADs without netting, which can entangle sharks.

To inform Regional Fisheries Management Organization (RFMO) requirements for fleets, ISSF shares science-based shark-conservation best-practices information through position statements and other outreach efforts. We also evaluate RFMO FAD management measures intended to help protect sharks.


Shark Photo Gallery

View and download photos of sharks from our photo gallery, taken by ISSF scientists and scientist-consultants.

Our Shark Videos

ISSF’s YouTube channel features exclusive videos about our shark research.

Biodegradable FADs Guide

Four tuna RFMOs already require the fleets in their regions that fish with FADs to use only non-entangling FAD designs. Some RFMOs additionally encourage fleets to use biodegradable materials in FADs.

ISSF’s Guide to Non-Entangling & Biodegradable FADs is a resource for RFMOs and fishers transitioning to more sustainable FAD designs.