Using distribution patterns of small fishes to assess small fish by-catch in tropical shrimp trawl fisheries

Publication Type: Journal Article

Year of Publication: 2014

Authors: Foster, SJ, Arreguin-Sánchez F

Journal: Animal Conservation

Issue: 17

Pagination: 217–224

Date Published: 11/2013

Keywords: conservation, fisheries, impact, non-target species, protected areas

Abstract:

Ecologically sound fisheries management and improving future food security
require that small fish by-catch in tropical shrimp trawl fisheries is maintained at,
or reduced to, sustainable levels; restricting trawling in particular places, or at
particular times, has been suggested as a means for achieving this goal. The
purpose of our research was to compare patterns in occurrence, density and body
size across depth, latitude and time for four small fish taxa caught as by-catch in
the southern Gulf of California shrimp trawl fishery: Diplectrum spp., Prionotus
stephanophrys, Pseudupeneus grandisquamis and Stellifer illecebrosus. We then
used these results to explore the potential for trawler impacts on these taxa, and
the possible placement and timing of fishing restrictions to mitigate potential
impacts. Our results confirmed, however, the difficulties of regulating such fisheries
for multiple by-catch species, in that their distribution patterns varied in a
way that precludes a ‘one size fits all’ solution. The four taxa analysed – only four
of the hundreds obtained as by-catch in this fishery – exhibited distribution
patterns at odds with one another. Observed intra- and inter-taxon variations in
the relative importance of different spatial and temporal variables in determining
occurrence, density and size argues that several permanent trawl closures covering
a range of depths and latitudes, and not temporal ones, might be required to
mitigate potential trawl impacts on these fishes. Our results also suggested a higher
potential for impact on S. illecebrosus than the other taxa: occurrence and density
of the former declined, whereas occurrence or density of the others increased
across the study area as the fishing season progressed.

DOI: 10.1111/acv.12078

Short Title: Anim Conserv