Anchovy Fishery Threat to Patagonian Ecosystem

Abstract

Spearfishing was becoming an increasingly important economic activity in the Caribbean as a result of socioeconomic factors related to underemployment and the low capital outlay for equipment. For a year (2011) we surveyed spearfishing in 23 Jamaican beaches. Spearfishing has expanded from approximately 1% of fishers in 1991 to about 10% in 2011. The fishery is larger than expected and probably produced 4 000tons per year. Though reef fishes dominated catches, other resources such as lobsters, conch and octopus were regularly taken. Many small juvenile fishes were observed in catches well below their adult or optimum sizes. A total of 58% of spear-fishers reported they would have significant difficulty finding alternative employment if spearfishing was banned. Spearfishers reported exploiting the entire island shelf and also nearly all the offshore banks, especially Pedro Bank. Night spearfishing was common and targeted sleeping reef fishes. The activity is banned and should be enforced. Our recommendations include: register all spearfishers, actively manage spearfishing, a partial ban for part of the year and a ban on using scuba and hookah gear for spearfishing. Rev. Biol. Trop. 62 (Suppl. 3): 141-149. Epub 2014 September 01.

Combined impact of ultraviolet radiation and increased nutrients supply: a test of the potential anthropogenic impacts on the benthic amphipod Amphitoe valida from Patagonian waters (Argentina)

“…In the case of the Chubut River, the input of nutrients is especially important due to human activities, e.g., through the use of fertilizers and input of effluents (Helbling et al, 1992). As a result, the area is characterized by a high productivity that supports an important fishery (Skewgar et al, 2007) as well as populations of birds and marine animals (Yorio and Quintana, 2008). In the last decades the Chubut River valley has increased its land use for agricultural purposes and herding, thus generating a large amount of nutrients via fertilizers that are carried out to the river.…”

Natural and anthropogenic factors affecting the feeding ecology of a top marine predator, the Magellanic penguin

“…v www.esajournals.org conspecifics (Tella et al 2001, Forero et al 2002a and fishing pressure (see Skewgar et al 2007, Yorio et al 2010. Indeed, increasing densities of conspecifics may increase competition for common resources among penguins and deplete more optimal prey types such as anchovy (Tella et al 2001, Forero et al 2002a.…”

“…Ours is the first to explore simultaneously the role of these different physical, biological and anthropogenic features likely affecting marine resources availability, and, consequently, driving the feeding and foraging ecology of this central-place forager. Accordingly, we provide a useful framework for evaluating v www.esajournals.org and predicting the potential impact of currently undergoing fishing policies such those aimed at developing a trawler fishery for anchovy as an alternative to the overfished hake (Skewgar et al 2007 and references therein) on Magellanic penguin populations. Consequently, this work supposes an important advance in the way we tackle the management and conservation of this species.…”

“…Competition may contribute to observed inter-colony differences in diet, but also result in poorer reproductive performance at those colonies experiencing high levels of competition (Tella et al 2001, Forero et al 2002a. Similarly, fishing activities may also affect diet, distribution and, ultimately, penguin reproductive performance since anchovy, hake and squid are important target species for commercial fisheries in the area (Argentinean ''Ministerio de Agricultura, Ganadería y Pesca,'' www.minagri.gob.ar; accessed on September 2012), suggesting high competition between fisheries and penguins (see Skewgar et al 2007, Yorio et al 2010.…”

“…In addition, the abundance and distribution of conspecifics and fishing vessels were expected to influence the diet and foraging distribution of penguins through a density-dependent depletion of optimal (i.e., high-protein) prey types (Tella et al 2001, Forero et al 2002a). We used remote sensing and geographic information systems (GIS) to derive several explanatory variables likely informing marine productivity patterns (Acha et al 2004), fishing pressure (Skewgar et al 2007, Yorio et al 2010, and intra-specific competition (Tella et al 2001, Forero et al 2002a. A species distribution model was used to quantitatively infer the role of different environmental features in explaining the at-sea distribution of penguins and general linear models were used to evaluate the effect of food availability on different dietary metrics (inferred from penguin blood d 13 C and d 15 N values).…”