Dear colleagues, 

we just published a comprehensive 51-pp review on cetaceans foraging behind 
trawlers, worldwide. 

For a pdf please contact the first author, Silvia Bonizzoni 
<silvia.bonizz...@gmail.com>.

Bonizzoni S., Hamilton S., Reeves R.R., Genov T., Bearzi G. 2022. Odontocete 
cetaceans foraging behind trawlers, worldwide. Reviews in Fish Biology and 
Fisheries. https://doi.org/10.1007/s11160-022-09712-z

ABSTRACT
Several populations of odontocete cetaceans, including at least 19 species, 
have modified their behavior and adapted to foraging in association with 
trawlers. We review information on odontocete interactions with different types 
of trawlers across 13 Food and Agriculture Organization fishing areas around 
the world. We also review knowledge gaps, the effects on odontocete ecology, 
distribution, behavior and social organization, the main mitigation options, 
and some management avenues that could help reduce incidental mortality. 
Trawlers involved in the interactions varied greatly in gear and target 
species, implying odontocetes have developed behavioral specializations to 
forage under a variety of conditions. Specialized behavior included venturing 
into a moving trawl net to feed on the organisms trapped in the net, feeding on 
fish stirred up by the net, extracting fish from the outer mesh, feeding on 
catch lost during hauling, and scavenging on discarded catch. Foraging behi!
 nd trawlers facilitates access to prey, and in some instances may compensate 
for scarcity of natural prey within areas exposed to intensive fishing or 
environmental degradation. This opportunistic foraging strategy, however, 
exposes the animals to potential harm and mortality in trawl gear. The combined 
effect of facilitated foraging and bycatch on the status and trends of 
odontocete populations is unknown. The economic damage caused by odontocetes, 
e.g. in terms of loss of marketable catch and gear damage, remains largely 
conjectural. Attempts to reduce depredation and/or bycatch in trawl gear have 
included acoustic deterrents and exclusion devices installed in nets, although 
neither technique has proven to be consistently effective.
-

A one-page synthesis can be found in the European Cetacean Society (2022) 
poster that can be downloaded from the link below:
https://www.dolphinbiology.org/_download/literature/Bearzi_etal_ECS_2022.pdf


Sincerely,

Giovanni Bearzi
https://www.dolphinbiology.org/people/giovanni_bearzi.htm





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