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Acoustic Discrimination

ISSF scientists are exploring innovative ways to use acoustic equipment at sea as a tool to prevent overfishing — and reduce bycatch — in purse-seine tuna fisheries.

We are studying how echosounder buoys near Fish Aggregating Devices (FADs), for example, can detect the distinctive “sound signatures” of different tuna species — and transmit that information to vessels before fishers travel to a FAD to make a set.

If fishers can harness acoustic technology to “preemptively” estimate the type and amount of fish (or “biomass”) gathered at a particular FAD, they can choose to fish only on FADs with higher proportions of tuna species for which stocks are in healthy condition — and avoid those that have attracted larger groups of non-target species.

Web Feature Story

Our Web feature story on acoustic discrimination — with animated illustrations and photos of ISSF research projects — shows how fishers can use acoustic technology to better identify species at FADs and to fish more sustainably.

Acoustic Signature Decoding

As a first step in leveraging acoustic technology to help differentiate the tuna species swimming at FADs, ISSF scientists have focused on decoding the species’ unique acoustic signatures. They have identified the signatures for skipjack, bigeye and yellowfin — an often-overfished species.

Insights from our current, multi-year acoustic research project with AZTI at IATTC’s Achotines Laboratory in Panama, for example, may help fishers to minimize catches of undersized yellowfin.

Through workshops with buoy manufacturers and fishers, we’ve disseminated results of the tropical-tuna acoustic discrimination project funded by the NOAA Bycatch Reduction Engineering Program (BREP).

Other ISSF acoustic research has been funded by the FAO GEF Common Oceans ABNJ Tuna Project, the Basque government, and NOAA fisheries.

Collaborative Projects

Since 2011, ISSF has partnered with fishers, marine scientists, and organizations like AZTI, the Secretariat of the Pacific Community (SPC), the Inter-American Tropical Tuna Commission (IATTC), and the Common Oceans ABNJ Tuna Project on a variety of acoustic research projects.

For example, we are working with acousticians to study how to reduce FAD impacts by using sonars to estimate biomass and validate echosounder readings.

On at-sea research cruises — including with these commercial fishing vessels — ISSF scientists have performed acoustic tagging and acoustic surveys, gathered data, tested equipment, and enhanced their understanding of tuna behavior at FADs:

Albatun Tres (with AZTI and Albacora )
Gutsy Lady 4 (with Tri Marine)
Mar de Sergio (with AZTI and Albacora)
Torre Giulia
Yolanda L (with Servigrup)

Several of these vessels appear on the ProActive Vessel Register.

Scientific Discoveries

In addition to our scientific reports and blog posts, ISSF scientists publish their acoustic research findings in leading fisheries and marine science journals, including co-authoring articles on “target strength” and tuna species discrimination.

To support tuna conservation and bycatch-mitigation efforts worldwide, ISSF shares our acoustic-discrimination research — and related recommendations — with fishers, Regional Fisheries Management Organizations (RFMOs), equipment manufacturers, and other sustainable-fishing stakeholders.