[MARMAM] New publication - Using a recreational echosounder to investigate predator-prey overlap in Hector's dolphin and little penguins

Tom Brough tom.broughnz at gmail.com
Thu May 23 02:24:23 PDT 2019


Kia ora MARMAM,

We are pleased to announce the recent publication of our article in PLoS
ONE.

Tom Brough, William Rayment and Steve Dawson. 2019. Using a recreational
grade echosounder to quantify the potential prey field of coastal
predators. PLoS ONE 14(5): e0217013.

Abstract

Quantifying the distribution of prey greatly improves models of habitat use
by marine predators and can assist in determining threats to both predators
and prey. Small epipelagic fishes are important prey for many predators yet
their distribution is difficult to quantify due to extreme patchiness. This
study explores the use of recreational grade echosounders (RGE) to quantify
school characteristics of epipelagic fish and link their distribution to
that of their predators at Banks Peninsula, New Zealand. The hydro-acoustic
system was groundtruthed with 259 schools of epipelagic fish. During 2015
and 2016, 136 hydro-acoustic surveys were conducted with concurrent
observations of Hector’s dolphin (Cephalorhynchus hectori) and little
penguins (Eudyptula minor). The relative abundance of the two predator
species during surveys was modelled according to the relative abundance of
potential prey using generalised additive mixed models. Schools of
epipelagic fish were readily detected by the RGE system and were more
abundant in summer compared to winter. The models performed well,
explaining 43% and 37% of the deviance in relative abundances of dolphins
and penguins respectively. This is the first study to link the distribution
of Hector’s dolphin to that of their epipelagic prey and confirms the
utility of RGE in studies of habitat use in marine predators. Limitations
associated with a lack of formal acoustic calibration and data formatting
can be overcome and would make RGE valuable, inexpensive tools for
investigating variability in populations of small pelagic fishes.

Full text pdf copies of the article are available at
https://doi.org/10.1371/journal.pone.0217013

Alternatively, feel free to email me at tom.broughnz at gmail.com for a copy,

Many thanks,

Tom Brough

*Marine Mammal Research Group*
*Department of Marine Science*
*University of Otago, Dunedin*
*Aotearoa/New Zealand*


*http://whaledolphintrust.org.nz/ <http://whaledolphintrust.org.nz/>*
*https://www.facebook.com/whaledolphintrust/
<https://www.facebook.com/whaledolphintrust/>*
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