Critical aspects of the Falkland Islands pelagic ecosystem: distribution, spawning and migration of pelagic animals in relation to oil exploration

Abstract

ABSTRACT1. The oceanography and topography of the southern Patagonian shelf, with the strong Falkland current deriving from the Antarctic Circumpolar current moving northwards both west and east of the Falkland Islands, creates an area of very high zooplankton productivity immediately to the north of the islands.2. Information on the distribution, spawning times and larval distribution of the most important fish and squid species is reviewed in this paper. High densities of macroplanktonic euphausid and hyperiid amphipods, especially in the summer, attract and sustain squid stocks (the pelagic Illex argentinus and bentho-pelagic Loligo gahi) and pelagic fish (Micromesistius australis and Sprattus fuegensis).3. There is an important spawning ground for three fish species having pelagic eggs and larvae (Micromesistius australis, Salilota australis and Sprattus fuegensis) on the shelf break immediately to the south and southwest of the Islands. The shelf surrounding the islands, and west and south towards the Argentine coast, forms a nursery area for the larvae of these and a number of other fish and squid species.4. Pollution emanating from the oil exploration tranches to the north of the islands or oil-based activities on the north shores of the Islands, although coincident with the area of high plankton productivity, would be unlikely to affect, in any major way the pelagic ecosystem around the Falkland Islands unless it became entrained in the area of slack water to the north of East Falkland. However, water flows from the Special Co-operation Area over critical spawning areas for a number of fished species (red cod, southern blue whiting and L. gahi) and has the potential to affect not only these but the Falkland shelf waters which act as a nursery area for many marine species.

DNA Metabarcoding as a Marine Conservation and Management Tool: A Circumpolar Examination of Fishery Discards in the Diet of Threatened Albatrosses

“…There was an unidentified clupeid in the diet at Diego Ramirez in (Arata and Xavier, 2003, and a small unidentified fish at New Island in 1987 that made up 80% of the fish prey (Thompson, 1992), which may have been sprat. This species has a high biomass across the southern Patagonian shelf as far as the Magellan Strait (Sánchez et al, 1995), Chilean channel waters (Diez et al, 2012) and around the Falkland Islands (Agnew, 2002), and is common in the diet of other seabirds and The hierarchical clustering of albatross diet and fishery catch data by month, based on the proportion of sequences (RRA, black text) and proportion of catch (blue text). Clusters were based on dissimilarity indices calculated with the Manhattan method, and hierarchical clustering was constructed using the average agglomeration method (note low sample sizes during January 2014 and 2015).…”

Predicting the distribution of a threatened albatross: The importance of competition, fisheries and annual variability

“…This region is also a spring spawning area for pelagic fish including the Fuegian sprat Sprattus fuegensis and the southern blue whiting Micromesistius australis (Agnew, 2002), which are common prey for black-browed albatrosses (own unpubl. data), and also for demersal fish such as red cod Salilota australis (Arkhipkin et al, 2010).…”

Segregation of SE Pacific and SW Atlantic southern blue whiting stocks: integrating evidence from complementary otolith microchemistry and parasite assemblage approaches

“…In the SWA area, massive westward migrations occur during the early winter, crossing the Burdwood Bank towards the Staten Island (Agnew 2002), where they tend to concentrate in August as gonads mature (Macchi and Pájaro 1999). From there, they seem to move northeast to reach the Falkland (Malvinas) spawning grounds (Fig.…”

“…Both are relatively long lived, highly mobile mesopelagic species that inhabit a wide depth range and engage yearly reproductive migrations to shallower waters in autumn, with massive spawning events in late winter-early spring. M. australis is associated predominantly with sub-Antarctic waters, at temperatures between 3 and 10°C (Figueroa et al 1998;Cassia 2000;Agnew 2002). This species is ubiquitous along the outer shelf and slope (130-800 m) of South America (South from 37°S), Antarctic Peninsula, Falkland (Malvinas) Islands, Scotia Ridge islands and New Zealand Plateau.…”