Relationship Between the Spatiotemporal Distribution of Dominant Small Pelagic Fishes and Environmental Factors in Mauritanian Waters

Abstract

The relationship between the spatiotemporal distribution of three dominant small pelagic fishes, including chub mackerel (Scomber japonicus), horse mackerel (Trachurus trecae) and round sardinella (Sardinella aurita), and the environmental factors in Mauritanian waters were analyzed by using 4 years of logbook data of commercial purse seine fisheries to improve the efficiency of fishery and management of sustainable exploitation. A Tweedie-generalized additive model (GAM) of 8-day average catches and the monthly geostatistical analysis of daily catches were used in this study to analyze the influence of environmental factors on catch per unit of effort (CPUEs) and to map the spatial distribution of three mixed dominant small pelagic fishes, respectively. A 10′ × 10′ grid was used, and environmental factors were processed from remote sensing, including 8-day average sea surface temperature (SST), the nearest distance between SST fronts and CPUE position (Df), chlorophyll-a (Chl-a) concentration, salinity, and eddy kinetic energy. Results showed that 1) the distribution of three dominant small pelagic fishes might be related to the intensity of upwelling in Mauritanian waters; 2) oceanic fronts might play a key role in the ecology of chub mackerel, horse mackerel, and round sardinella; 3) Chl-a concentration might be associated with the feeding grounds of chub mackerel; 4) the target species distribution appeared sensitive to gradient changes in the amount of salinity; 5) three zones (northern, central, and southern) with variable abundances were delineated; and 6) a high concentration of the center of gravity in the central zone might be related to the strong upwelling of nutrient-rich waters. This study can provide new insights to enhance the fishery efficiency and sustainable exploitation management of purse seiners in certain area off Mauritania.