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Marine Mammal Assessments at the NEFSC

A major goal of the Marine Mammal Protection Act (MMPA) is to allow marine mammal populations to rebuild and remain at the population’s Optimum Sustainable Population level. To accomplish this goal the data collection and management scheme depicted below was developed.  To go through this scheme, start with the programs that collect the basic data (human-induced mortalities, abundance, and stock structure).  These data are then used to assess the status of each stock which is annually updated in the Stock Assessment Reports. A stock is considered “strategic” when the level of human-induced mortalities (such as by-catch in commercial fisheries and ship-strikes) is larger than the Potential Biological Removal (PBR) level.  PBR is derived from abundance estimates and measures of uncertainty in the estimates of abundance and mortalities.  According to the MMPA if a stock is considered strategic, then a Take Reduction Team (TRT) must be created to develop a Take Reduction Plan, which is a plan to reduce the mortalities to levels below PBR.  The monitoring/data collection programs continue updating the mortality and abundance estimates.  So, if updated estimates indicate that the level of human-induced mortality is above the PBR level then the Take Reduction Plan must be updated with the goal to reduce the levels of mortalities.  The Scientific Review Group is an independent group of scientists that reviews the scientific issues involved in this scheme.  

PSB and other parts of NMFS are involved in most of these steps within the data collection and management scheme.

assessment flow chart

In the Atlantic there are 5 TRTs to which PSB contributes information.

Large whale TRT

North Atlantic right whale

humpback whale

fin whale

minke whale

Balaena mysticetus

Megaptera novaeangliae

Balaenoptera physalus

Balaenoptera acutorostrata

Northeast trap/pot

Mid-Atlantic trap/pot

Southeast trap/pot

Northeast gillnet

Mid-Atlantic gillnet

Southeast gillnet

Atlantic trawl gear TRT

long-finned pilot whale

short-finned pilot whale

common dolphin

white sided dolphin

Globicephala melas

Globicephala macrohynchus

Delphinus delphis

Lagenorhynchus acutus

Mid-Atlantic mid-water trawl

Mid-Atlantic bottom trawl

Northeast mid-water trawl

Northeast bottom trawl

Harbor porpoise TRT

Gulf of Maine/Bay of Fundy harbor porpoise

Phocoena phocoena

Northeast gillnet

Mid-Atlantic gillnet

Coastal bottlenose dolphin TRT

coastal bottlenose dolphin

Tursiops truncatus

Mid-Atlantic gillnet

Virginia pound net

Mid-Atlantic haul/beach seine

Atlantic blue crab trap/pot

North Carolina inshore gillnet

North Carolina roe mullet stop

North Carolina long haul seine

Southeastern US Atlantic shark gillnet

Southeast Atlantic gillnet

Pelagic Longline TRT

long-finned pilot whale

short-finned pilot whale

Globicephala melas

Globicephala macrohynchus

Atlantic pelagic longline


Observer data needed to estimate by-catch rates in commercial fisheries is collected by the Northeast Fisheries Observer Program (NEFOP), also part of the NEFSC.  PSB analyzes these observer data and uses additional databases to estimate bycatch that is attributed to commercial fisheries. PSB also uses the observer data to investigate what types of gear characteristics and environmental factors are associated with high bycatch.  This type of information has been very helpful to the Take Reduction Teams in developing a plan to reduce bycatch.

PSB is also involved in collecting the needed data and analyzing those data to estimate abundance of cetaceans and seals

fisheries observeraerial observer seals on Wasque

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