Error message

Deprecated function: The each() function is deprecated. This message will be suppressed on further calls in menu_set_active_trail() (line 2385 of /srv/data/web/vhosts/www.indiseas.org/htdocs/includes/menu.inc).

Humboldt (Northern) - Exploitation

The northern Humboldt Current System off Peru produces more fish per unit area than any other region in the world oceans, representing less than 0.1% of the world ocean surface but presently producing about 10% of the world fish catch (Chavez et al., 2008). In Peru, each subsystem (pelagic, demersal and coastal) is clearly differentiated and species inhabiting each of them are exploited by a particular fleet.

Pelagic Subsystem
The coastal pelagic subsystem is characterized by cold and rich upwelled waters (i.e. CCW). Pelagic fish are targeted by purse seiners (Fig. 2) and comprise 95% of the Peruvian catches, the most important being the neritic anchovy (Engraulis ringens), sardine (Sardinops sagax), the transzonal jumbo squid (Dosidicus gigas), jack mackerel (Trachurus murphyi) and chub mackerel (Scomber japonicus). The anchovy population has been recognized as the largest neritic fish population and the largest single fishery stock ever recorded. The anchovy fishery has spanned three stages since 1953, the first from 1953 to 1972 with a maximum annual catch of 12 million t (1970), the second in which a stock collapse (1973) was followed by 20 years of low anchovy biomass, and the third since 1992 to the present, the present time with a recovery of catch levels and a maximum annual catch of ~10 millions t (1994). Fisheries scientists and managers tend to agree that the 1970s collapse was caused by a combination of both fishery-related and natural factors (e.g. Alheit and Niquen, 2004). The low level anchovy period was characterized by an increase in sardine catches with a maximum annual of 3.5 millions t in 1988, whereas horse mackerel and chub mackerel reached maxima of 750 000 t in 2001 and 400 000 t in 1989 respectively. According to their observed abundances, the invertebrate jumbo squid and mesopelagic Panama lightfish (Vinciguerria lucetia) are also important but only the first is commercially exploited (maximum annual catch of 400 000 t in 2011). The less abundant longnose anchovy (Anchoa nasus) and mote sculpin (Normanichthys crokeri) are considered to be interesting indicators of the approach of equatorial waters from the north and sub-Antarctic waters from the south respectively, i.e. warming or cooling of the system.

Demersal Subsystem
Near the equator, the HCLME is bordered by the Equatorial Undercurrent (EUC) (Wolff et al., 2003), which runs eastward parallel to the equator, ranging from about 2°N to 2°S. Before reaching the South American west coast, the current divides into northern and southern branches. The subsurface (50-300 m) and oxygen-rich waters (0.25-2.0mL.L-1; Moron et al., 2001) of the southern extension of the Cromwell Current (SECC) penetrate southward alongshore Peru (classically up to 9°S and up to 14°S during El Niño), favouring the existence of a rich demersal subsystem. Consequently, demersal species dynamics are highly variable, depending on the intensity and southern range of extension of the SECC in northern Peru (Samame et al., 1985; Espino et al., 1995). Demersal species are caught by bottom trawlers (Fig. 3) mainly for direct human consumption. Peruvian hake (Merluccius gayi peruanus) is the main target species. Peruvian rock seabass (Paralabrax humeralis), Peruvian banded croaker (Paralonchurus peruanus) and lumptail searobin (Prionotus stephanophrys) are caught as by-catches, but still important for human consumption. Two important periods have marked the hake fishery since 1966. During the 1970s, foreign large factory trawlers caught a maximum annual catch of about 300 000 t (1978). Then, during the 1990s, a local modernized trawler fleet developed, with a maximum annual catch of more than 200 000 t (1996) (Wosnitza-Mendo et al., 2004). Important population and ecological changes have been identified for hake and the demersal community, such as the drastic reduction in mean length of hake in 1992 and 1998 (Guevara-Carrasco and Lleonart, 2008). Overfishing diminished hake reproductive capacity, modified the sex ratio in favour of females and increased population vulnerability to environmental stress, in particular to the El Niño (Wosnitza-Mendo et al., 2004; Ballón et al., 2008).

Coastal Subsystem
For fishery management purposes, the Coastal nearshore subsystem is restricted to the west by the 5 nautical mile limit parallel to the coastline. It is dominated not only by fish species but also by an important diversity and biomass of benthic invertebrates. These are caught by a large artisanal fleet (e.g. around 10 000 vessels) (Fig. 4) able to land almost up to 400 000 t fish and shellfish per year for direct human consumption (Estrella and Swartzman 2010). Typically, the most abundant fish are the South Pacific bream (Seriolella violacea), mullet (Mugil cephalus), South Pacific menhaden (Ethmidium maculatum) and drum (Sciaena deliciosa). Scallop (Argopecten purpuratus), mussel (Aulacomya ater) and snail (Concholepas concholepas) are the domimant invertebrates (Wolff et al., 2003).