Oceanic and atmospheric patterns during spawning periods prior to extreme catches of the Brazilian sardine (<i>Sardinella brasiliensis</i>) in the southwest Atlantic

Abstract

SUMMARY: Relative maxima and minima of landings of Brazilian sardine captured in the Southeast Brazil Bight (SBB) were compared with oceanic and atmospheric composites relative to the spawning period in December and January, prior to these landings. Atmospheric and oceanic variables such as wind stress, Ekman transport, mixing index, sea surface temperature (SST), precipitation, outgoing long wave radiation and geopotential height were analyzed, revealing distinct climatological patterns in the SBB for these extreme catches that have not been described before. The system could be characterized by cooler SST composite anomaly (SSTA) along the SBB as a response to increased cloud cover and reduced incidence of short-wave radiation, predominating one year before the Brazilian sardine catch maxima. This system can take on a different configuration in which positive SSTA condition in the SBB is associated with a less intense South Atlantic Convergence Zone displaced southwards one year before the period of minimum catch. Our results indicate that the spatial structure of the spawning habitat is influenced by specific ocean-atmosphere interactions rather than simply resulting from the choice of a stable environment. This climatic constraint strongly affects the interannual variability of the Brazilian sardine production.Keywords: Brazilian sardine, southwest Atlantic climate, air-sea interaction, South Atlantic Convergence Zone, sea surface temperature, Southeast Brazil Bight.RESUMEN: Patrones oceánicos y atmosféricos durante períodos de puesta previos a capturas extremas de la sardina brasilera (Sardinella braSilienSiS) en el océano Atlántico sudoeste. -Los desembarcos máximos y mínimos de capturas de la sardina brasileña en la Plataforma Sudeste Brasilera (SBB) se compararon con los patrones climáticos oceánicos y atmosféricos durante períodos de puesta, en diciembre y enero. Se analizó el comportamiento climático de variables oceanicas y atmosféricas como la influencia del viento, el transporte de Ekman, el índice de mezcla, la temperatura superficial del mar (SST), las precipitaciones, la radiación ascendente de ondas largas (OLR) y la altura geopotencial. Este análisis permitió la identificación de patrones climatológicos característicos sobre la SBB, no observados en trabajos previos. Los análisis revelaron que el sistema se caracteriza por SSTA más fríos sobre la sardina como respuesta a un incremento de la nebulosidad y la reducción de la incidencia de las radiaciones de onda corta, que predominan un año antes de las máximas capturas de sardina. Este sistema puede asumir una configuración distinta en la que SSTA positivos sobre la SBB se asocian con una SACZ desplazada hacia el sur un año antes del periodo de capturas mínimas. Nuestros resultados indican que la estructura espacial del hábitat de puesta es una consecuencia de las interacciones específicas océano-atmósfera, más que de una elección de ambiente estable y que ello influencia fuertemente la variabilidad interanual en la producción de sardina brasile...

Reconstruction of Marine Commercial Landings for the Brazilian Industrial and Artisanal Fisheries From 1950 to 2015

“…Sardinella brasiliensis is one of the main cases of collapse in Brazilian waters, whose landings reached the lowest level in 1990, and again in 2000, triggering the establishment of the Committee for Management of Sustainable Use of Sardine in 2005 and the preparation of a plan for the sustainable use of this resource in Brazilian waters in 2011 (Cergole and Dias-Neto, 2011). As a pelagic resource, it is also highly impacted by interannual environmental changes (see, e.g., Soares et al, 2011). Future analysis should include environmental factors as an association with El Niño events was already found (see, e.g., Paes and Moraes, 2007;Soares et al, 2011).…”

“…As a pelagic resource, it is also highly impacted by interannual environmental changes (see, e.g., Soares et al, 2011). Future analysis should include environmental factors as an association with El Niño events was already found (see, e.g., Paes and Moraes, 2007;Soares et al, 2011). Sardine catches increased from 2000 until 2015, but more current data must be analyzed to check if this trend has been maintained.…”