Comparative study of skipjack tuna <em>Katsuwonus pelamis</em> (Scombridae) fishery stocks from the South Atlantic and western Indian oceans

Abstract

The skipjack tuna, Katsuwonus pelamis, inhabits tropical and subtropical oceans the world over, and contributes substantially to total tuna catches. Both fishing pressure and anthropic influences affect skipjack populations, impacting on economic returns and investment. The present study analyses and compares spatial time series of catch and catch per unit effort (CPUE), of pole-and-line fishing of skipjack tuna from Brazil, South Africa and the Maldives. Both regional and inter-regional analyses were conducted for the period 1970-2014 in order to ultimately investigate potential associations between these fisheries, climatic conditions and the El Niño Southern Oscillation (ENSO). Correlation tests and spatial mapping tools were used. From 2004 to 2011, South African skipjack catches correlated positively with Brazilian ones and negatively with Maldivians. CPUEs from the Brazilian and Maldivian skipjack fisheries showed a significant positive correlation in the period 1982-1993. Yearly catches from all regions were strongly associated with the Northern Oscillation Index (p &lt; 0.001), an ENSO index. This study reflects an effort to articulate an inter-regional appraisal of skipjack pole-and-line fisheries embedded in the context of a globally changing climate, in the face of which emerging economies are the most vulnerable. Evidence of common patterns influencing these fisheries should encourage international South-South cooperative management and understanding of the resource.

Climate change, tropical fisheries and prospects for sustainable development

“…Climate-related shift in spatial distribution of marine species has been recorded in both coastal and offshore waters [235][236][237] ; some species (such as the Brazilian sardine) are moving to cooler and deeper waters, whereas others (squid) have migrated to areas with warmer winter temperatures 238 . Rising sea levels and hydroclimatic variability, for example, have resulted in loss of mangrove and wetland habitats 239 , including in the Amazon and Pantanal floodplains 230 , and this is expected to have knock-on effects of the production of fisheries associated with these habitats.…”

Aggregative capacity of experimental anchored Fish Aggregating Devices (aFADs) in Northeastern Brazil revealed through electronic tagging data

“…Purse seine fishing around FADs is currently responsible for more than half of the tuna catches worldwide (Parker et al, 2014). Due to the great economic importance and environmental impacts of these activities, most of the studies dedicated to the behavior of FAD-associated species, and the relationship between the fish and the FAD, have focused on tunas (Dahlet et al, 2019;Moreno et al, 2019;Oshima et al, 2019).…”