Influence of oceanographic variability on recruitment in the Illex argentinus (Cephalopoda:Ommastrephidae) fishery in the South Atlantic

Abstract

'~e p a r t m e n t of Zoology, University of Aberdeen. Tillydrone Avenue, Aberdeen AB24 2TZ, United Kingdom ABSTRACT: The fishery for IUex argentinus in the Southwest Atlantic is subject to large inter-annual variability in recruitment strength. In this paper we attempt to build a predictive model using sea surface temperature (SST) to examine links between recruitment to the Falkland Islands fishery and environmental variability during the juvenile and adult life history stages. SST data from the National Center for Atmospheric Research (NCAR) were found to be comparable with near-surface data derived from in situ expendable bathy-thermograph (XBT) profiles in the southern Patagonian shelf. Variation in SST during the early Me stages appears to be important in determining recruitment of I. argentinus.SST in the hatching grounds of the northern Patagonian shelf during the period of hatching (particularly June and July) was negatively correlated with catches in the fishery in the following season. SST anomaly data from positions in the Pacific and Southwest Atlantic were used to examine teleconnections between these areas. Links were seen at a lag of 2 yr between the Pacific and southern Patagonian shelf, and at about 5 yr between the Pacific and northern Patagonian shelf. This is consistent with SST anomalies associated with El Nifio in the Pacific propagating around the globe via the Antarctic Circumpolar Wave (ACW). Predicting cold events via teleconnections between SST anomalies in the Pacific and Atlantic would appear to have the potential to predict the recruitment strength of I. argentinus in the Southwest Atlantic.

Impacts of climate variation and potential effects of climate change on South American seabirds – a review

“…Wind-driven coldwater current systems such as the Falkland/Malvinas Current are strongly affected by climate forcing. For example, ENSO-mediated SSTAs generated in the Pacific propagate to the Southwest Atlantic with a lag of 2Á3 years via the Antarctic Circumpolar Current (Waluda et al 1999); furthermore, the Antarctic Oscillation, i.e. fluctuations in the strength of the circumpolar vortex, may also have an influence (Silvestri & Vera 2003).…”

“…Gentoo penguins mainly feed on fish and squid that occur close to their breeding sites (e.g. Masello et al 2010), and the abundance of their prey is influenced by environmental variability (Waluda et al 1999(Waluda et al , 2004, which may vary locally across the archipelago. In contrast, thin-billed prions and rockhopper penguins feed on zooplankton and range widely over the Patagonian Shelf and, in the case of the prions, into the Drake Passage to the south.…”

Wavelet analysis of correlation among Canary Islands octopus captures per unit effort, sea-surface temperatures and the North Atlantic Oscillation

“…In this way, yearly recruitment (Robin and Denis, 1999), and consequently the availability to the fishery (Agnew et al, 2002;Chen et al, 2006), is conditioned by the effects that climatic variability has on their relatively large pelagic paralarvae stages in relation with their longevity (Waluda et al, 1999). Therefore, it is likely that those climatic variables that can be measured at surface level (i.e., SST) may have direct effects on the survival rates of these pelagic stages.…”

“…Therefore, it is likely that those climatic variables that can be measured at surface level (i.e., SST) may have direct effects on the survival rates of these pelagic stages. The influence could be explained either through growth, food availability or natural mortality due to other causes (Forsythe, 1993;Caveriviere et al, 1999;Robin and Denis, 1999;Waluda et al, 1999;Leporati et al, 2007;Pierce et al, 2008). It could therefore be more feasible to differentiate climatic effects from the influence of fishing in these species, because their response to environmental fluctuations should be faster (Hernández-García et al, 2002;Chen et al, 2006;Caballero-Alfonso et al, 2010).…”

Environmental influences on commercial oceanic ommastrephid squids: a stock assessment perspective

“…The Falkland Islands fishery consists almost exclusively of winter spawners and fishery managers assume that it target a single stock (SPS) south of 45°S (Brunetti and Ivanovic 1992). China (Lu and Chen 2013), Chinese Taipei (Chen and Chiu 2009) and the Falkland Islandshave exploited the SPS cohort of I. argentinus since 2000 (Waluda et al 1999).…”