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The Argentine shortfin squid (Illex argentinus) sustains one of the world's largest squid fisheries. This squid presents strong interannual fluctuations in abundance, attributed to its semelparous life strategy coupled with environmental influences on recruitment. Several stocks have been identified, but the south patagonic stock (SPS) is the most abundant and the main support (ca. 80%) of the Argentine fishery. SPS spawns in autumn–winter, but there are controversies regarding the spawning ground location. We studied the relationship between the recruitment variability and oceanographic conditions to which eggs and paralarvae are exposed, considering two possible spawning ground locations: Patagonia and Southern Brazil. We tested the hypothesis that the SPS recruitment variability could be controlled by oceanographic fluctuations related to the transport of the egg masses spawned on each of the two grounds, to their retention on the continental shelf and to the attainment of the thermal habitat required for eggs hatching. We used a 24‐ years long time series (1993–2017) of catch per unit effort of the squid fishery, and a shorter stock‐assessment series as recruitment proxies; and satellite data of SST and of geostrophic velocities derived from sea surface height. This information was employed to model the advection of the squid egg masses along the external shelf and slope and to estimate the annual recruitment success. Results show that if spawning occurs in Patagonia, 52% of the recruitment variability could be explained. On the other hand, if spawning occurs in southern Brazil, it does not result in successful recruitments for the SPS. [ABSTRACT FROM AUTHOR]

Cannibalism by fishes on planktonic eggs is typical of filter-feeding marine planktivores, i.e. fishes that have the ability for filtering large volumes of water and concentrate small food particles. We report an unusual case of cannibalism on planktonic eggs by adults of the non-filter feeding fish Micropogonias furnieri, which are opportunistic bottom-feeding carnivores that prey mainly on polychaetes, molluscs and crustaceans. Spawning of M. furnieri takes place in the innermost part of the Rı´o de la Plata estuary, near the upstream edge of a salinity wedge. Strong haloclines retain planktonic eggs in a bottom salty layer, thin enough to generate spatial coexistence of the planktonic eggs and the bottom associated adults. Moreover, eggs remain sufficiently concentrated as to be sucked in by fish lacking filtering apparatus. It has been stated that cannibalism appears to be genetically based but controlled or induced by different environmental cues. Our case, however, shows that environmental influence on cannibalism is not restricted to a signal that triggers the cannibalistic behavior: oceanographic processes may also act generating specific scenarios that promote and perhaps regulate the occurrence of cannibalism. [Copyright &y& Elsevier]