[MARMAM] new paper on right whale entanglement rates

Amy Knowlton aknowlton at neaq.org
Tue Oct 23 08:21:23 PDT 2012

Dear Colleagues, 


We are pleased to announce the publication of the following in Marine
Ecology Progress Series:


Knowlton AR, Hamilton PK, Marx MK, Pettis HM, Kraus SD (2012) Monitoring
North Atlantic right whale Eubalaena glacialis entanglement rates: a 30
yr retrospective. Mar Ecol Prog Ser 466:293-302


ABSTRACT: Entanglement in non-mobile fishing gear has been identified as
one of the leading causes of mortality in North Atlantic right whales
Eubalaena glacialis. To investigate this issue further, all available
photographs of right whales taken from 1980 to 2009 were examined for
evidence of entanglement with gear used in fisheries based on presence
of rope or netting on the whale or scars inferred to have been caused by
an encounter with rope. Photographs of 626 individual whales were
assessed and 1032 unique entanglement events were documented. Of the 626
animals, 519 (82.9%) had been entangled at least once and 306 of the 519
(59.0%) had been entangled more than once. Males and females were
entangled at similar rates. Juveniles were entangled at a higher rate
than adults. On average, 25.9% of adequately photographed animals
acquired new wounds or scars from fishing gear annually with no
significant trend over time detected. However, the annual percentage of
animals observed with rope on the body increased significantly during
the study period, suggesting that it is becoming more difficult for
whales to free themselves completely from fishing gear. Such high annual
rates of entanglement remain a serious conservation concern for right
whales because entanglements can have both lethal and sub-lethal
effects. Federally required changes to fixed-gear fisheries in US waters
have not reduced serious injuries and mortality to legally required
levels. Here we show how documenting various annual rates of
entanglement can monitor progress and impacts that fishing gear
regulations may have on right whale recovery. 


KEY WORDS: North Atlantic right whale * Eubalaena glacialis * Fishing
gear * Entanglement * Scars * Conservation 


The paper is Open Access and available here:




Amy Knowlton

Research Scientist

John H. Prescott Marine Laboratory

New England Aquarium

Central Wharf

Boston, MA 02110

(617) 973-0210


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