Bycatch is the term given to the accidental capture of marine life in fishing gear and is a global conservation and fisheries management issue. It is now seen as by far the single most serious, direct threat to cetaceans.  Globally, it is estimated that at least 300,000 cetaceans are caught and killed as bycatch every year. 

Cetaceans can become entangled or wrapped in various types of fishing gear including nets, ropes and lines. Smaller species often die immediately as they are unable to reach the surface to breathe. The large size of some cetacean species means entanglement may not kill them immediately but instead can become a serious welfare issue as they tow heavy ropes, buoys and nets for weeks, months or years before dying. 

Bycatch of cetaceans occurs in all kinds of fishing operations: from large industrial to localised artisanal fisheries. It also occurs in most types of fishing gear. Gillnets and entangling nets are known to cause the highest amount of cetacean bycatch. Large whales are particularly susceptible to becoming entangled in nets and ropes associated with pots and traps and Fish Aggregating Devices (FADs) which are used to attract fish. 

In general, across the world's fisheries there is quite limited bycatch monitoring, data collection and reporting of data. This makes it difficult to assess and identify priority locations and populations on national and international scales.  Some technical solutions do exist for assessment, monitoring and mitigation, and work is ongoing to promote proven uptake of these solutions and appropriate testing of them in fisheries around the world. 

USA Fisheries Bycatch Reporting

All U.S. fishing vessel owners or operators must report all incidental mortalities and injuries of marine mammals that occur during commercial fishing operations under the Marine Mammal Authorization Program. In addition, NMFS’s Regional Fishery Observer Programs, Marine Mammal Health and Stranding Response Program, and Large Whale Entanglement Response Programs document and report marine mammal mortalities and injuries incidental to commercial fishing operations.

USA Current Threats to Cetacean Conservation and Management Measures Taken/Proposed

Interaction with fishing gear can incidentally injure and kill cetaceans and is a leading human-related cause of mortality and serious injury for multiple cetacean species (including North Atlantic right whales and harbor porpoise in the Atlantic Ocean, bottlenose dolphins in the Atlantic Ocean and Gulf of Mexico, humpback whales in the Eastern Pacific Ocean, and false killer whales in the Pacific Ocean). NMFS works with the fishing industry and other experts to develop or modify fishing gear and practices to minimize bycatch.

USA Current Government Programs Related to Cetacean Conservation

The Marine Mammal Commission (Commission) is an independent agency of the U.S. government charged by the Marine Mammal Protection Act (MMPA) to further the conservation of marine mammals and their environment. The Commission works to ensure that marine mammal populations are restored and maintained as functioning elements of healthy marine ecosystems. It provides science-based oversight of domestic and international policies and actions of other U.S. federal agencies with regulatory authority for, or whose actions may affect marine mammals and their ecosystems.

USA Current Government Programs Related to Cetacean Conservation

In August 2016, NOAA Fisheries published a final rule implementing the fish and fish product import provisions of the Marine Mammal Protection Act (MMPA) (81 FR 54390; August 15, 2016). This rule establishes conditions for evaluating a harvesting nation’s regulatory programs to address incidental and intentional mortality and serious injury of marine mammals in fisheries producing fish and fish products exported to the United States.

USA Legal Protections

The Marine Mammal Protection Act (MMPA) contains provisions to address the incidental mortality and serious injury of marine mammals in both domestic and foreign commercial fisheries. With respect to foreign fisheries, section 101(a)(2) of the MMPA states that the Secretary of the Treasury shall ban the importation of commercial fish or products from fish which have been caught with commercial fishing technology which results in the incidental kill or incidental serious injury of ocean mammals in excess of United States standards.

Gabon Marine Conservation

Gabon Bleu is a presidential marine conservation initiative to manage Gabon's coastal and oceanic waters and create a marine protected area network. Gabon Bleu also aims to improve industrial and artisanal fisheries, offshore oil and gas, and maritime security. Gabon Bleu works with local and international NGOs like WCS and WWF. Examples of the intiative's achievements include:
1. New Fisheries and Aquaculture Agency (ANPA)
2. An Ocean Council (CNM)
3. New legislation to create fishing zones and better apply fisheries law.

UK Threats and Measures


The two main species affected by fishing in UK waters are the harbour porpoise and the shortbeaked common dolphin. All Reports to the European Commission on activities conducted by the UK under Regulation 812/2004, and under Article 12(4) of the Habitats Directive, provide details of the monitoring work undertaken and estimates of bycatch.

NZ Threats and conservation measures

Hector’s and Māui dolphins

In 2008, the Department of Conservation and Ministry for Primary Industries put in place a Hector’s and Māui dolphin Threat Management Plan (TMP) that identifies human induced threats to Hector’s and Māui dolphin populations and outlines strategies to mitigate those threats.6 This plan provides a platform in which to guide research, engagement, management and review processes.