Title
Spatial ecology of blue shark and shortfin mako in southern Peru: Local abundance, habitat preferences and implications for conservation
Date Issued
01 January 2016
Access level
open access
Resource Type
research article
Author(s)
Adams G.D.
Adams G.D.
Adams G.D.
Flores D.
Flores O.G.
Aarestrup K.
Svendsen J.C.
Svendsen J.C.
Gulf Coast Research Laboratory
Instituto del Mar del Peru
Peace Corps Peru
Instituto del Mar del Peru
Instituto del Mar del Peru
Technical University of Denmark
CIIMAR - Interdisciplinary Centre of Marine and Environmental Research
Technical University of Denmark
Abstract
While global declines of pelagic shark populations have been recognized for several years, conservation efforts remain hampered by a poor understanding of their spatial distribution and ecology. Two species of conservation concern are the blue shark Prionace glauca and the shortfin mako shark Isurus oxyrinchus. To improve management of these species, this study examined their local abundance patterns, habitat preferences, and distribution in the Southeast Pacific. Catch per unit effort (CPUE) data from an artisanal fishery in Peru were used to identify geographic hot spots and model abundance estimates as a function of environmental variables, including the El Niño Southern Oscillation (ENSO). A 10 yr data series revealed declining annual landings since 2012, despite no changes in management structures. Significant aggregations of both species were found in southwestern Peruvian waters (74-76°W, 17-19° S), with both speciesspecific hot spots targeted by major fishing efforts. P. glauca CPUE increased during La Niña conditions (i.e. low water temperature anomaly), and CPUE of both species declined when water depths exceeded 1000 m. Correlations with lunar illumination and chlorophyll a were revealed in P. glauca and I. oxyrinchus, respectively. Modeling explained 57 to 61% of the deviance, indicating that other factors not included in the present study might account for unexplained variance in CPUE (e.g. thermocline depth, location of marine fronts, dissolved oxygen, and gear characteristics). Given the importance of the examined area to shark fisheries and the exploitation of multiple species of conservation concern, the information presented here can be used to inform management strategies designed to limit the depletion of pelagic sharks.
Start page
19
End page
32
Volume
31
Issue
1
Scopus EID
2-s2.0-84994627632
Source
Endangered Species Research
ISSN of the container
16134796
Sources of information: Scopus Directorio de Producción Científica