[MARMAM] New Publication: River dolphin mortality events in the Amazon

Veronica Iriarte verorcinus at gmail.com
Mon Jun 3 07:02:05 PDT 2013

                              We are pleased to announce the following
publication in Aquatic Mammals:

Iriarte, V. & Marmontel, M. (2013). *River dolphin (Inia geoffrensis, Sotalia
fluviatilis) mortality events attributed to artisanal fisheries in the
Western Brazilian Amazon.Aquatic Mammals, 39(2): 116-124. DOI:

*ABSTRACT:* In the Western Brazilian Amazon, interactions of boto (*Inia
geoffrensis*) and tucuxi (*Sotalia fluviatilis*) dolphins with fishing
activities are common, but the prevalence of incidental/intentional catches
is not known. This article describes incidental mortality events and
intentional killing of *I. geoffrensis* and *S. fluviatilis* entangled in
artisanal fishing gear and the opportunistic use of carcasses as bait.
Between October 2010 and November 2011, surveys were conducted in waters of
the lower Japurá River, between the Mamirauá and Amanã sustainable
development reserves. In order to obtain information on interactions and to
try to establish a stranding/entanglement response program (SERP), informal
conversations were exchanged with local inhabitants (n = 174). Intense
carcass-search surveys (n = 171) along the river in the four hydrological
seasons (e.g., low, rising, high, and falling waters) were conducted,
comprising a total of 1,197 h of sampling effort. Twenty-five
dolphin–fishing interaction events were recorded (11* I. geoffrensis* and
14 *S. fluviatilis*), 19 in 2011 and six in 2012 (through SERP). A total of
11 necropsies (three *I. geoffrensis* and eight *S. fluviatilis*) were
performed. Four individuals (two* I. geoffrensis* and two *S. fluviatilis*)
exhibited evidence of physical violence before death, and two (one* I.
geoffrensis* and one *S. fluviatilis*) died in abandoned gillnets. Two
intentional killing events of* I. geoffrensis* incidentally entangled for
bait use in the piracatinga (*Calophysus macropterus*) fishery were
reported by fishermen, while three carcasses (two* I. geoffrensis* and one *S.
fluviatilis*) with gillnet marks were also used in that activity. At least
six of the *S. fluviatilis *entanglement events occurred in fishing gear
used for tambaqui (*Colossoma macropomum*) and pirapitinga (*Piaractus
brachypomus*) (90/100-mm mesh-size gillnet), two of the most important
commercial fish species in the Amazon Basin. As seasonal fishing
constitutes the main income for riverine human populations, the negative
reactions that cetacean presence causes to people could have a catalyst
effect for the transition from “incidental capture” to “intentional capture
and competitor removal.” Law enforcement and precautionary measures through
good fishing practices inside dolphin critical foraging areas should be
taken together with fisheries’ managers and fishermen to start to develop
multiple-species management and ensure sustainable fishing practices.

The article is available at:  http://www.aquaticmammalsjournal.org

PDF copies can be requested to: verorcinus at gmail.com

Verónica Iriarte
Grupo de Pesquisa em Mamíferos Aquáticos Amazônicos
Instituto de Desenvolvimento Sustentável Mamirauá
Estrada do Bexiga 2584, Bairro Fonte Boa
Tefé, Amazonas
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