Independent Advisory Team for Marine Mammal Assessments

Marine mammals face a number of challenges from human-induced stresses, including incidental entanglement in fishing gear, such as gill nets, crab or lobster trap lines, and trawls. As part of the legal requirement to protect marine mammals established by the Marine Mammal Protection Act (MMPA) of 1972 and its amendments in 1994, each marine mammal stock in U.S. waters needs to be assessed regularly in order to monitor its conservation status.

Independent Advisory Team for Marine Mammal Assessments, Science Center for Marine Fisheries, Gulf Coast Research Laboratory
Humpback Whale
Source: Wikimedia Commons/Whit Welles

Assessment requires a reliable estimate of abundance and a reliable estimate of how many marine mammals are seriously injured or killed annually in fishing gear. The difficulty of detecting and counting marine mammals, combined with their complex migratory behavior and the dynamic distribution of fishing activities, makes assessment of the risks to marine mammal stocks from fisheries challenging. If fishermen and managers were able to better characterize and assess the risks to marine mammals associated with each fishery, for example where and when marine mammal “hotspots” overlap with the fishing activity, they would be better able to reduce or prevent any adverse effects of the fishery on the marine mammal stocks.

Dr. Paula Moreno manages a project of GCRL's Science Center for Marine Fisheries (SCeMFiS) aimed at better understanding the status of marine mammals and improving the methods used to evaluate the risks posed by fisheries. The project relies on a team of four scientists with expertise in stock assessment techniques and in marine mammal interactions with fisheries. Ultimately, this project is intended to facilitate long-term sustainability of both marine mammal stocks and marine fisheries and thereby support the objectives and requirements of the MMPA.

Among the key subject areas being investigated is how to refine existing approaches for estimating “allowable” (i.e. safely sustainable) rates of human-caused serious injury and mortality. Potential Biological Removal (PBR) levels are calculated regularly for each marine mammal stock during the assessment process. These levels take into account information on stock abundance, productivity, and status.  When bycatch in a given fishery exceeds the PBR (or a set percentage of PBR), this triggers measures to reduce and monitor the bycatch in that fishery.

The project is co-funded by the National Science Foundation through SCeMFiS and its membership. (SCeMFiS is funded by the National Science Foundation Industry/University Cooperative Research Program. Funding is provided directly by NSF plus membership fees paid by private companies, trade organizations and federal agencies that have joined SCeMFiS.) Dr. Moreno is the Principal Investigator. Work began in August 2013, with the first phase to be completed by late spring 2014. At present, the project's study area is limited to the U.S. Atlantic Exclusive Economic Zone, where 52 marine mammal stocks occur, but the outcomes are expected to be applicable to other regions, including the U.S. Gulf of Mexico where approximately 57 marine mammal stocks have been identified. The project’s study area may be expanded in a later phase to include the Gulf explicitly to help to address specific challenges in this region.

Project Goals and Objectives

Year 1

Efforts are aimed at (a) reviewing the state of knowledge concerning marine mammal stocks and their interactions with fisheries and (b) recommending research to fill significant gaps.
This is to be accomplished by:

Year 2 and Beyond

The results of funded research after Year 1 would be expected to lead to reduced uncertainty in stock assessments, and hence improved policy and management. This could include the development of a framework for better understanding the impacts on marine mammals of particular fisheries and for tuning management in ways that benefit both conservation and fisheries. The ultimate objective would be to provide a stronger scientific foundation to facilitate and guide efforts to conserve marine mammal stocks and ensure sustainable fisheries.

Education Objectives

Scientists with expertise in quantitative techniques to estimate abundance and trends, particularly as applied to marine mammals, are in great demand. One objective of this project is to involve and train students, thus helping to meet that demand in the future.

Independent Advisory Team

The Independent Advisory Team (IAT) has been selected and consists of the following scientists:

Other project contributors include:

Understanding Marine Mammal Stocks

Knowledge of many marine mammal stocks and their interactions with fisheries is not adequate to meet the conservation and protection goals of the MMPA or to ensure that fisheries regulations are defensible and effective. Difficulties include the following:

The MMPA requires that marine mammal stocks are monitored and that annual Stock Assessment Reports (SARs) are published covering all stocks of cetaceans (whales, dolphins, and porpoises), pinnipeds (seals, sea lions, and walruses), manatees, sea otters, and polar bears in U.S. waters. These SARs are the fundamental basis for all science and policy efforts by U.S. government agencies in relation to marine mammals. The current levels of uncertainty in SARs for many species are very high.

The key parameter for marine mammal stock assessment is the PBR level, defined by the MMPA as "the maximum number of animals, not including natural mortalities, that may be removed from a marine mammal stock while allowing that stock to reach or maintain its optimum sustainable population." PBR values are currently unknown for nearly one third of the 52 Atlantic stocks. For most of the Atlantic stocks (90 to 95%), PBR levels currently rely on general default values rather than species-specific values for at least some inputs, for instance the rate of population growth.

This project will attempt to find ways to reduce uncertainty in stock assessments and PBR estimates. An initial step will be to examine and summarize existing data from various sources, including the SARs. Particular attention will be given to the question of what survey data are available for the various marine mammal stocks.

New Data Sources and Stock Assessment Methodologies

Ongoing technological advances are providing new and potentially powerful sources of data on marine mammals, fisheries, and the marine environment. Examples include enhanced vessel tracking and reporting systems, satellite-linked sensing and tracking systems, buoy data collection systems, drones and gliders, and survey programs such as the Atlantic Marine Assessment Program for Protected Species.

The project team will seek innovative ways to use these new and emerging resources to improve stock assessments. Modeling is certain to be a valuable tool in future work. Risk assessment models and stock simulations can be used to examine the range of potential effects where knowledge and data are uncertain, and thus provide needed guidance for policy-making and research prioritization.

Independent Advisory Team for Marine Mammal Assessments, Science Center for Marine Fisheries, Gulf Coast Research Laboratory
Captain Budd Christman, NOAA Corps,
NOAA Photo Library