the humboldt current system of northern and central chile - figema

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MARTIN THIEL ET AL.Niño 3.4 index32A10−1−2−31982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006Scallop seeds (n bag −1 )600500400300200100N° of scallop seeds by collector bagN° of collector bagsB30252015105Collectors (100,000 bags)01982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 20060Harvest (1000 t)20161284Natural Gacilaria productionCultivated Gacilaria productionC01982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006Figure 28 (A) SST anomalies for the time period 1982–2006 (from http://iri.columbia.edu/climate/ENSO);(B) average number of scallop Argopecten purpuratus settlers per collector bag (individuals bag −1 ) and thenumber of collector bags placed in Bahia Tongoy (30°S); (C) harvest of Gracilaria chilensis between 18°Sand 35°S from natural banks and from culture beds. (Source for A and B: SERNAPESCA, Region IV, Chile.)on the populations of large kelps and other macroalgae in northern Chile (Vásquez 1999). Kelpaquaculture is presently in a developmental phase and has not yet achieved economic importance.Other resources currently being investigated for aquaculture in northern Chile are bivalves fromsandy beaches (Mesodesma donacium, Tagelus dombeii). Culture of these bivalves is aiming atstock repopulations after extinction of local stocks (see also Artisanal benthic fisheries, p. 278ff.).Additionally, there are several introduced species that are presently cultured in northern Chile.The Pacific oyster (Crassostrea gigas) was originally introduced in northern Chile in the 1970s,and despite fast growth rates, aquaculture activities then moved to southern Chile because thereculture costs are cheaper (bottom culture vs. suspended culture in northern Chile). The productionin northern Chile is marginal, and there are only two oyster companies remaining. During the firsthalf of 2004 these produced only 935 t, which represents a 46.8% decrease compared with theproduction during the first half of 2003. The influence of ENSO on the production of oysters isnot well known, but since Pacific oysters have a wide range of temperature tolerance EN effectsmay be minor (or positive).294
THE HUMBOLDT CURRENT SYSTEM OF NORTHERN AND CENTRAL CHILEOther species introduced to the coast of Chile are abalone, originating from California andJapan. These have been mainly cultured in land-based facilities, but due to an increasing productionand limited holding capacities on land, sea-based culture (as already established in southern Chile)is also considered for northern-central Chile. The production of abalones increased from 1 t in1998 to 342 t in 2005, and for the year 2006 it is expected that the Chilean abalone industry willproduce >500 t. Only in Region IV, currently five abalone production centres are established andan additional five centres have solicited permits to initiate new aquaculture activities during 2006.The present abalone production in Chile is mainly based on the red abalone (Haliotis rufescens).However, the Japanese abalone (H. discus hannai), which has a better market value, is also raised,but to a lesser degree since culture technology has higher requirements (and costs) than those forred abalone.Although the land-based abalone culture is not directly affected by variations in environmentalconditions, ENs may have severe effects on abalone culture because they can produce strong impactson the population of large kelp, the main food resource presently used in abalone culture. The lackin supply of fresh food algae may produce serious bottlenecks in the culture of abalone. Some ofthese problems are occurring presently and the National Fisheries Service (SERNAPESCA) isconcerned with the overexploitation of kelp, restricting the extraction from natural kelp beds andpromoting research for cultivation and management of seaweeds. This scenario presents importantchallenges for applied research in the near future.In general, aquaculture in northern and central Chile does not reach the levels it has in southernChile. Some of the main reasons for this are related to the fact that the coast of northern Chile is(1) mostly exposed to wave action and (2) is strongly affected by important interannual variationsin oceanographic conditions. Future efforts should probably focus on the development of landbasedculture facilities and integrated systems where animals and algae are produced in combination(Chopin et al. 2001).Conservation of marine biodiversityand Marine Protected AreasThe HCS extending from Ecuador to southern Chile is considered as one of the large marineecosystems for high-priority attention (Boersma et al. 2004). The growing use of coastal areas byhuman activities is also increasingly threatening marine biodiversity in the HCS. The most importantthreats are overfishing, aquaculture, pollution by sewage and mining activities, runoffs of chemicalsused for agriculture, oil spills and tourism activities (Vásquez et al. 1999, Fernández et al. 2000).All countries, including Chile, that have ratified the Convention on Biological Diversity (CBD)treaty agreed to develop a network of Marine Protected Areas (MPAs, as defined by IUCN 1994)to ultimately protect 10% of the marine environments by 2012, based on an ecosystem approach(Wood 2006). However, the actual establishment rate of MPAs (4.5% annual increase) reveals thatthe work plan is unrealistic and will not be achieved before the second half of this century (Wood2006). The Chilean case is a paradox as its economic exclusive zone (EEZ) corresponds to 17.8%of the Latin-American EEZ and is three times larger than its terrestrial territory (~18% of which isalready protected; Pauchard & Villarroel 2002). However, only 0.03% of the Chilean EEZ (0.67%of the territorial sea) is protected as MPAs (CONAMA personal communication). Further, only14% of the surface area of these MPAs are located within the HCS of northern and central Chile(18°S to 41°S). Considering that ~95% of the Chilean population is located between 18°S and 41°Sand the growing human impact in coastal areas, this zone represents one of the greatest challengesfor marine conservation.The Chilean fisheries management policy, through creation of Management and ExploitationAreas (AMERBs) for benthic resources from coastal habitats, is focusing on economically important295
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