Dear MARMAM Readers,
On behalf of my co-authors, I am pleased to share our recent publication, which will be available in the next issue of Aquatic Mammals:
Rechimont M.E., Lara-Domínguez A.L., Morteo E., Martínez-Serrano I., Equihua M. En prensa. Depredation by coastal bottlenose dolphins (Tursiops truncatus) in the southwestern Gulf of Mexico in relation to fishing techniques. Aquatic Mammals 44(5):458-470. ISSN: 1996-7292, doi: 10.1578/AM.44.5.2018.458
Abstract: Cetacean–fishery interactions are a recurring
problem. These interactions are conflict prone,
especially between fishers and those seeking
marine mammal conservation. In the southwestern
Gulf of Mexico, a large fleet of artisanal fisheries
operates using a range of different techniques. We
recorded 90 fishing operations in two different
fishing areas of Veracruz, Mexico, between 2009-
2010 and 2014-2015, assessing whether dolphin
interaction negatively affects fish catch and fish
gear. These potential impacts were evaluated
using three generalized linear models (GLMs)
hypothesizing that (1) depredation decreases catch
per unit effort (CPUE), (2) the predator presence
modifies catch composition, and (3) prey species
presence increases the likelihood of depredation.
Of the gillnet hauls analyzed, 27 were subject to
depredation by bottlenose dolphins, despite conditions and fishing methods varying among sites.
Higher CPUE attracts larger pods, but a negative
effect by depredation was not detected. We also
found that depredation probability increased when
there were higher capture volumes, when mackerels and jacks were present, and when operations
were most southwesterly. Despite the short distance (< 80 km) between sites, we found that bottlenose dolphins on each site displayed different
feeding behaviors towards fishing nets. Regarding
conservation, bycatch caused by dolphins does
not seem to be problematic. In fact, the increase
in boat traffic and declining prey abundances due
to overfishing could be the main causes of fishers’
economic loss. Dolphin–fishery interactions may
not represent an actual challenge for marine conservation managers, but stakeholders, fisheries,
and governmental institutions should be aware that diminishing returns due to overfishing could
exacerbate the apparently false notion of dolphins
competing for the fish.
Key Words: catch composition, fishing gear,
CPUE, interactions, PNSAV-Marine Protected Area,
Veracruz
Thanks!
Eduardo Morteo, Dr.
Head Researcher Level C
Marine Mammal Laboratory (LabMMar, IIB-ICIMAP)
Institute of Biological Research
Universidad Veracruzana
Calle Dr. Castelazo Ayala S/N, Col. Industrial Ánimas, Xalapa, Veracruz, Mexico, CP 91190.
Ph/Tel: +52 (228) 841 89 00
E-mail: emorteo@uv.mxhttp://www.uv.mx/personal/emorteo/
http://uv-mx.academia.edu/EMorteo
https://www.researchgate.net/profile/Eduardo_Morteo/?ev=hdr_xprf