Marine Mammal Commission

Marine Mammal Bycatch

Marine mammal bycatch refers to any marine mammal adversely affected as a result of being unintentionally entangled, ensnared, or caught by nets, lines, traps, or hooks, or otherwise interacting with fishing gear. Because bycatch is the greatest direct cause of marine mammal injury and death in the United States and around the world, Section 118 of the Marine Mammal Protection Act (MMPA) requires the National Marine Fisheries Service (NMFS) and the U.S. Fish and Wildlife Service (FWS) to address marine mammal bycatch through science, gear research, and restrictions on fishing gear and practices.

National Bycatch Strategy

NMFS has developed priorities and strategies for reducing fisheries bycatch at the national level, as part of its National Bycatch Reduction Strategy. Those priorities and strategies are reviewed periodically to incorporate new information and research. Comments submitted by the Commission on NMFS’s National Bycatch Strategy are listed below (see “Learn More” section).

The federal management framework for monitoring and mitigating bycatch is based on methods to estimate the ability of marine mammal populations to sustain human-related mortality (i.e., the potential biological removal, or PBR, of each marine mammal stock), assessment of the numbers of animals taken, and take reduction efforts based on structured consultations among fishery managers, scientists, conservationists, and fishermen on NMFS’s take reduction teams. The Marine Mammal Commission’s 2014 Priorities Report underscores the need for regular stock assessments for marine mammal species that are impacted by fishery interactions. In addition, there is a need for increased observer coverage within and across fisheries to ensure reliable estimates of bycatch. Observed bycatch mortality is a fraction of the total mortality due to fisheries interactions. Many deaths go undetected and are referred to as cryptic mortality. The Commission is planning a workshop in 2016 that will address the problem of fully accounting for mortalities that are not detected through observer data or strandings.

We are also looking for ways to create economic incentives to reduce marine mammal bycatch in fisheries. For example, in September 2015 we co-hosted with NMFS an international workshop on incentive-based fishery bycatch measures. This workshop focused on incentives such as individual transferable bycatch allocations to provide greater flexibility to fishing vessel operators to reduce their marine mammal bycatch in a more cost effective manner.

Take Reduction Teams (TRTs)

NMFS Take Reduction Teams

Atlantic Large Whale

Atlantic Trawl Gear

Bottlenose Dolphin

False Killer Whale

Harbor Porpoise

Pacific Offshore Cetacean

Pelagic Longline

The seven active TRTs around the United States review and recommend specific bycatch reduction measures for particular fisheries (e.g., Atlantic pot/trap, California drift gillnet, Hawaii shallow- and deep-set longline) through a negotiated, multi-stakeholder process. The TRTs are mandated with the goal of reducing marine mammal bycatch to levels below PBR within six months, and to reduce bycatch to levels approaching the zero mortality rate goal within five years. Not all TRTs are successful, and the Commission continues to strive for effective measures and their full implementation and enforcement through active participation on all the TRTs. The Commission’s 2015 Annual Meeting included a session examining TRT performance, with a specific discussion of the factors determining successes and challenges in some of the East Coast TRTs.

Learn more about TRTs and the development of take reduction plans.

Value of Research and Fishery Bycatch Data

Hooked false killer whale.

Hooked false killer whale from the Hawaii long-line fishery. (Eric Forney, NOAA)

Reliable and accurate fisheries bycatch data are critical to develop policy measures aimed at reducing the impacts of fisheries bycatch on marine mammals. Elements needed to accurately assess and mitigate the impacts of fisheries bycatch on marine mammals include:

  • the ability to collect fisheries bycatch data (e.g., through fishery observer programs),
  • the ability to assess the abundance and trends of marine mammal stocks (e.g., through marine mammal surveys), and
  • the ability to test the effectiveness of mitigation efforts aimed at reducing interactions between marine mammals and fishery operations.

In many cases, insufficient resources for collecting accurate fisheries and marine mammal data has resulted in poor or dated management information, particularly PBR estimates. The uncertainty and lack of data create a need for precautionary fishery bycatch measures that may be more restrictive than necessary, leading to unnecessary economic losses in commercial fisheries. Studies have shown that a modest increase in resources for marine mammal data collection results in more tailored bycatch reduction measures, and therefore higher profits to commercial fishermen. Lack of data and research has also limited progress in assessing the ecological effects of fishing on marine mammals and marine ecosystems, which are often much more challenging to assess and mitigate.

A ring seal entangled in fishing equipment image

A ring seal entangled in fishing equipment. (NOAA)

To help address these issues, the Commission co-sponsored two workshops with NMFS to look at innovative and cost-effective ways of collecting marine mammal data needed to develop more accurate stock assessments. One workshop examined the use of unpiloted aerial vehicles (drones) to survey marine mammals, and to collect data on their condition and behavior. The second workshop focused on the use of passive acoustics deployed on fixed or towed arrays, or housed in floated buoys or autonomous underwater vehicles (gliders), to detect and estimate the density of marine mammals from their calls.

We fund relevant research through our grants program and provide advice on measures to reduce bycatch. We also are seeking partnerships with other government agencies, industry and the private sector to look for economic incentives for the development and use of new technologies for collecting bycatch data.

learn more

Marine Mammal Commission Letters

April 25, 2016:
Letter to NMFS on proposed rule to establish a Standardized Bycatch Reporting Methodology.

March 25, 2016:
Letter to NMFS on proposed rule for Seafood Import Monitoring Program.

November 9, 2015:
Letter to NMFS on proposed rule to prohibit imports of seafood products.

July 10, 2015:
Letter to NMFS providing preliminary input on revisions to the National Bycatch Strategy.