MEPS 622:157-176 (2019)  -  DOI: https://doi.org/10.3354/meps12996

ABSTRACT: Overexploitation and climate change can reduce the abundance and shift the spatial distribution of marine species. Determining the habitat suitability of a mobile pelagic species, such as blue marlin (BUM) Makaira nigricans and black marlin (BAM) Istiompax indica, can help describe their spatiotemporal distribution patterns over a broad spatial scale, which is crucial for fisheries management. We applied a species distribution model (MaxEnt) to model the dynamic suitable habitat of BUM and BAM using 14 yr (1997-2010) of Inter-American Tropical Tuna Commission occurrence data (n = 20348) from purse-seine vessels in the eastern Pacific Ocean (EPO) and high-resolution remotely sensed oceanographic data. The spatial distribution of suitable habitat for both species varied seasonally and in response to El Niño-Southern Oscillation (ENSO), with BUM positively correlated with chlorophyll a (chl a) concentrations and sea surface temperature and BAM with chl a concentrations and sea surface height. The influence of these environmental variables shifted seasonally suitable habitat between coastal (winter and spring) and oceanic (summer and fall) waters. During La Niña events, suitable habitat was along the equator, while during El Niño, suitable habitat shifted to farther northern and southern waters of the EPO. Analyses on species’ centers of suitable habitat (CSH) revealed that the strength of ENSO did not influence CSH; however, large displacements were observed during these events. The models applied in our study provide critical information on the spatiotemporal patterns of 2 mobile pelagic predators, which can potentially be used to forecast future distributions and develop effective management strategies in response to climate change.

KEY WORDS: Distribution shift · Black marlin · Blue marlin · Marine pelagic fish · Satellite remote sensing data · Incidental catch · MaxEnt · Species distribution model · Tuna purse-seine fishery