November 2025

Circle hooks (non-offset 16/0 and 18/0) did not significantly reduce the number of loggerhead sea turtles (Caretta caretta) caught in the Azores longline swordfish and blue shark fishery when compared with non-offset and offset 9/0 J hooks. Use of circle hooks decreased the rate of throat hooking in loggerhead sea turtles. Circle hooks (non-offset 16/0 and 18/0) caught significantly more blue sharks than J hooks in the Azores longline swordfish and blue shark fisheries. 

Acoustic Harassment Devices were not found to be effective in deterring New Zealand fur seals (Arctocephalus forsteri) from mid-water trawls in the New Zealand hoki fishery. Sea Lion Escape Devices are undergoing testing in New Zealand˙s hoki trawl fishery (for fur seals) and the squid trawl fishery (for Hookers˙s sea lion). Preliminary results indicate squid and fish loss via the escape hatch was minimal; in the hoki fishery, fish loss was confined to fast swimming species, including jack mackerel and warehou.

Historically, the whale shark has been hunted for its meat and liver oil. Whale shark fins are considered inferior in quality and the species is generally not targeted for its fins, although a market for them does exist in Asia due to their massive size (Norman 2005). Despite the fact that there is a paucity of data regarding whale shark bycatch, it is believed that the species most commonly becomes entangled in purse seines, longlines, and gillnets, particularly set nets. Whale sharks are slow-growing, attain reproductive maturity late in life, and reach large sizes (Colman 1997; Jones & Kaly 1995). These factors mean that it may be difficult for whale shark populations to recover after mortality events due to hunting or bycatch (Jones & Kaly 1995). Worldwide, bycatch is thought to be one of the leading causes of declining shark populations (Cosandey-Godin & Morgan 2011). Compounding the problem, there is a lack of regulations related to shark bycatch mitigation (Stevens et al 2000). In 1995, an estimated 158 whale sharks were accidentally entangled in nets in Taiwanese waters (Chen et al 1996). Whale sharks are also deliberately killed in this region, as there is a high demand for the meat (Chen et al 1996; Norman 2005). In Indian coastal waters, whale sharks are accidentally caught with regularity by small-scale, artisanal fisherman (Silas 1986). Accidental entanglement of whale sharks is also problematic in Zanzibar (Norman 2005), and in Indonesia, where the sharks are attracted to nets full of caught fish. Whale sharks are frequently found near schools of fish like tuna and bonito; this can lead to accidental entanglement when these fish are targeted by purse seiners (Silas 1986; FFA 2011). possible mitigation measures for whale shark purse seine bycatch include the use of deterrents (Cosandey-Godin & Morgan 2011), the use of smaller stretch mesh (Schaefer & Fuller 2011), the development of ecological fish aggregating devices intended to decrease shark bycatch (Franco et al 2011), and the prohibiting of purse seining in areas occupied by whale sharks (FFA 2011). Species awareness campaigning and ecotourism activities such as dive-with-whale-shark programs may prove to be valuable as well, as evidenced by the development of stakeholder-mediated programs in the Seychelles that have benefitted both humans and whale sharks (Rowat & Englehardt 2007).  

References

Chen, GCT, K Liu, S Joung & MJ Phipps, 1996. Traffic report on shark fisheries and trade in Taiwan. In The World Trade in Sharks: a Compendium of TRAFFIC’s regional studies, pp. 271-322. TRAFFIC Network, Cambridge, UK.

Colman, JG. 1997. A review of the biology and ecology of the whale shark. Journal of Fish Biology 51: 1219-1234.

Cosandey-Godin, A & A Morgan. 2011. Fisheries bycatch of sharks: Option for mitigation. Ocean Science Division, Pew Environmental Group, Washington, DC. PDF available http://www.pewtrusts.org/uploadedFiles/wwwpewtrustsorg/Reports/Protecting_ocean_life/Pew_OSS_shark_bycatch_review.pdf Accessed 28 November 2012.

Forum Fisheries Agency (FFA). 2011. FFA members proposed CMM to prohibit purse seine fishing associated with whale sharks. Scientific Committee Seventh Regular Session, August 9-17, 2011, Federated States of Micronesia. WCPFC-SC7-2011/EB-WP-13. 3 pp.

Franco, J, G Moreno, J Lopez & I Santocristobal. 2011. Testing new designs of drifting fish aggregating devices (DFAD in eastern Atlantic to reduce turtle and shark mortality. International Commission for the Conservation of Tunas SCRS/2001/067.

Jones, GP & UL Kaly. 1995. Conservation of rare, threatened and endemic marine species in Australia. In LP Zann & P Kailola (eds), The State of the Marine Environment of Australia Technical Annex: 1. The Marine Environment. pp. 183-191. Ocean Rescue 2000, Department of the Environment, Sport and Territories, Canberra.

Norman, B. 2005. Rhincodon typus. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. Accessed 28 November 2012. http://www.iucnredlist.org

Rowat, D & U Englehardt. 2007. Seychelles: A case study of community involvement in the development of whale shark ecotourism and its socio-economic impact. Fisheries Research 84: 109-113.

Schaefer, KM & DW Fuller. 2011. An overview of the 2011 ISSF/IATTC research cruise for investigating potential solutions for reducing fishing mortality of undesirable sizes of bigeye and yellowfin tunas and sharks in purse-seine nets on drifting FADs. Scientific Committee Seventh Regular Session, August 9-17, 2011, Federated States of Micronesia. WCPFC-SC7-2011/EB-WP-13. 5 pp.

Silas, EG. 1986. The whale shark (Rhiniodon typus Smith) in Indian coastal waters: Is the species endangered or vulnerable? Marine Fisheries Information Service 66: 1-21. Stevens, J, R Bonfil, NK Dulvy & P Walker. 2000. The effects of fishing on sharks, rays, and chimaeras (chondrichthyans), and the implications for marine ecosystems. ICES Journal of Marine Science 57: 476-494.

This paper focuses on mitigation measures specified by the International Commission for the Conservation of Atlantic Tunas (ICCAT) related to threatened seabirds foraging in the south Atlantic Ocean. The authors developed an ecological risk assessment for various combinations of mitigation measures to protect five threatened albatross and petrel populations, comparing those specified by ICCAT to those recommend by the Seabird Bycatch Working Group of the Agreement on the Conservation of Albatrosses and Petrels (ACAP). They conclude that updating existing mitigation measure specifications for pelagic longlining in the South Atlantic to reflect current best practice guidelines would potentially reduce seabird mortality by 41–86 %, and predict that simultaneous application of all three ACAP recommended mitigation measures recommended (includingnight setting, branch line weighting, bird-scaring lines, and hook shielding devices) could reduce seabird mortality by 72–93 % and therefore should be considered by ICCAT.

Pearl Nets, a passive acoustic deterrent, were tested in commercial gillnet fisheries in the Western Baltic Sea. Compared to a control, the Peal Nets reduced harbor porpoise bycatch and maintained target catch rate for Atlantic cod.

The Consortium for Wildlife Bycatch Reduction was founded in 2004 by Duke University, Maine Lobstermen’s Association, New England Aquarium, and University of New Hampshire. Blue Water Fishermen’s Association joined the Consortium shortly thereafter. Administered by Dr. Timothy Werner of OAI Consulting and UMASS-Boston, the Consortium supports collaborative research between scientists and the fishing industry to identify practical bycatch reduction solutions for endangered species.

The Consortium’s focus is in three primary areas: 

• Understanding interactions between threatened non-target species and fishing operations
• Research and development of bycatch reduction approaches
• Facilitating global exchange of information on bycatch reduction techniques

The Consortium’s underlying philosophy is that a science-industry partnership is the best way to identify effective and sustainable bycatch solutions. Further, its members recognize that change in fishing practices should be commercially viable, operationally practical, and use the best available science to evaluate the degree to which they will result in bycatch reduction benefits for non-target species. Equally important, even if a fishing technique is shown conclusively to reduce bycatch in a particular non-target species or population, it should not pose an increased threat to other endangered species or for that matter be unsustainable for marine biodiversity in general. In this respect the Consortium’s work program adheres to an ecosystem-based approach.

Currently, the Consortium promotes the Global Bycatch Exchange for promoting collaboration in reducing fisheries bycatch. We encourage you or your group to share a profile and help advance the Exchange as a platform for creating partnerships.

This study examined spatial interactions between false killer whales (Pseudorca crassidens) and the Hawaii-based deep-set longline fishery. False killer whales occur as bycatch in this fishery that exceed allowable levels. Five satellite tagged whales (occurring within three groups) in combination with logbook entries showed that only two groups of whales approximated gear at a distance closer than 50km. On two occasions whales from one group came close enough to interact with gear, and one of six sets involved had no catch which may be explained by depredation. The haul phase showed the highest “attraction effect,” and the results suggest this portion of fishing activity may be an important factor in bycatch, especially seeing as at other times the whales showed limited time interacting with gear.

This study evaluated the cetacean interactions with a bottom-set net fishery along the mainland Portuguese Southern coast (Algarve) from 2018-2022. Depredation by bottlenose dolphins occurred in 17.7% of hauls, while bycatch occurred in

The Consortium for Wildlife Bycatch Reduction, in collaboration with Ocean Associates, Inc., and with funding from Broadreach, is pleased to announce the availability of grants for reducing marine bycatch.

Ocean Associates, Inc., in collaboration with the Consortium for Wildlife Bycatch Reductionand with funding from the National Marine Fisheries Service Office of International Affairs andSeafood Inspection, is pleased to announce the availability of grants to support capacity building

for reducing marine mammal bycatch.

Black Sea Harbour porpoise (Phocoena phocoena relicta) bycatch mitigation in the Bulgarian waters of the Black SeaFinal report

January 2020

GHANA WILDLIFE SOCIETY

Final Report to Anderson Cabot Center for Ocean Life at the New England Aquarium

PROJECT TITLE: Baseline Assessment on Marine Mammal Bycatch along the Coast of Ghana during 2019-2020

Attached is a list of Recipients of the 2020 grants

Mapping Cetacean Occurrence and Bycatch in Indian Waters: Bridging Knowledge Gaps Through Fisher Community Networks

There was no significant difference in the number of loggerhead sea turtles caught in the Azores longline swordfish and blue shark fishery between straight 16/0, offset 16/0, and offset 18/0 circle hooks. Circle hooks decreased the rate of throat hooking in loggerhead sea turtles caught in the Azores longline swordfish and blue shark fishery. Straight 16/0 circle hooks caught the most blue sharks in the Azores longline swordfish and blue shark fishery, followed by offset 18/0 circle hooks. Offset 16/0 circle hooks caught the fewest blue sharks.