the humboldt current system of northern and central chile - figema

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MARTIN THIEL ET AL.natural processes in the HCS. Recognition of this impact has called increasingly for planning andregulation of human activities. The limited predictability of oceanographic conditions and theecological processes in the HCS, however, represents an enormous challenge for efficient managementof this large marine ecosystem. Herein we strive to describe those aspects of the system thatare comparatively predictable and to identify those that will require additional knowledge beforethey can be reliably predicted. In order to achieve this goal, this review provides (1) a brief overviewof historic research activities, (2) a description of the main oceanographic conditions in the HCS ofnorthern and central Chile, (3) an analysis of the pelagic environment and top consumers, (4) anintroduction to benthic systems and nearshore biogeography, (5) a discussion of biological adaptationsof organisms, (6) a portrayal of socioeconomic aspects related to the exploitation of naturalresources, and finally (7) a scenario for marine conservation and an outlook identifying some ofthe main administrative and scientific tasks for the future.A brief history of research on the Humboldt current systemFirst reports on a cool current in the southeastern PacificFirst written accounts of a cold current along the western coast of South America come from theEuropean explorers. According to Gunther (1936), the history of the Humboldt Current began in1515 when Vasco Nuñez de Balboa first sighted the South Sea. The knowledge of this oceaniccurrent dates to the sixteenth century when several Europeans carried out observations suggestingthat waters were cool: Pascual de Andagoya in 1522 was the first Spaniard to explore to the southof the Panamanian coast, Agustin de Zarate published in 1555 his Historia del descubrimiento yConquista de la Provincia del Peru, and the Jesuit José de Acosta described in his Historia Natural yMoral de Indias (1591) the temperature conditions and their influence on the climate (Santibáñez1944). Other travellers carried out additional observations (for details see Gunther 1936), but itwas the German naturalist Alexander von Humboldt who took the first temperature measurements(Gunther 1936, Santibáñez 1944). Humboldt (1846), in his book Cosmos, wrote on page 301: “inthe Southern Pacific Ocean, … a current the effect of whose low temperature on the climate of theadjacent coast was first brought into notice by myself in the autumn of 1802. This current bringsthe cold water of high southern latitudes to the coast of Chile, and follows its shores and those ofPeru northward”. Additionally, Humboldt also was the first to describe EN temperature anomaliesin coastal waters (Kortum 2002).From natural history to ecology to marine conservationThe first Chilean naturalist was Abate Juan Ignacio Molina. He published the following works inItaly: Compendio della storia geografica, naturale, e civili del regno del Chile (1776) and Saggiosulla storia naturale del Chili (1782), which include detailed descriptions of the mineral wealthand native flora and fauna based on the Linnaean system of classification (Ronan 2002). ClaudioGay, a French naturalist who arrived in Chile in 1828, as a result of 12 yr of exploring Chile undergovernment contract, wrote his Historia fisica y política de Chile. In 29 volumes Gay describedthe history, botany and zoology of the country, including detailed descriptions of the marine fauna(e.g., 79 species of decapod crustaceans) (Jara 1997). Rodulfo Amando Philippi, who emigratedfrom Germany to Chile in 1851, was a physician by profession but a naturalist by inclination, andhe is considered one of the most recognised and influential scientists in the development of naturalsciences in Chile (Castro et al. 2006). He contributed numerous taxonomic descriptions to theknowledge of biological diversity of Chile. In a recent article, Castro et al. (2006) conclude thatin comparison with other taxonomists, Philippi was the author of the largest number of presently200
THE HUMBOLDT CURRENT SYSTEM OF NORTHERN AND CENTRAL CHILEvalid species in the Chilean biota. Other scientists who contributed enormously to the knowledgeof the fauna and flora from the HCS of northern-central Chile included Alcide D’Orbigny, EduardFriedrich Poeppig and Carlos Emilio Porter Mosso.Most expeditions during the eighteenth and nineteenth centuries produced observations andcollections that were gathered by individual scientists or ‘naturalists’ aboard global voyages ofexploration and discovery. These voyages often had political, military and economic purposes, withscience being a secondary or even incidental activity (Fiedler & Lavín 2006). After Humboldt’stravels, several pioneer expeditions were carried out in the southern Pacific, but most of themrounded Cape Horn on their way into the Pacific, stopped in Concepción or more commonly inValparaíso, and then turned off to Juan Fernández and from there progressed further into thesouthwest Pacific. The coasts of northern Chile were rarely visited by these expeditions. Also theU.S. Exploring Expedition (1838–1842), the main objective of which was to facilitate Americancommerce (Johnson 1995), left the coast of northern Chile untouched on its way from Valparaísoto Callao. Other expeditions took the same route on their return trips. For example, the NovaraExpedition passed through Valparaíso in April 1859, coming from Tahiti. The corvette H.M.S.Challenger reached Valparaíso in November 1875 coming from Juan Fernández and then continuedto the south. Later expeditions, such as the Fisheries Commission Steamer Albatross, with AlexanderAgassiz on board, explored the northern parts of the HCS, but rarely reached farther south thanCallao, Peru. A notable exception to this general pattern was the H.M.S. Beagle (1831–1836), withCharles Darwin aboard, which after leaving Valparaíso made stopovers in Coquimbo (30°S), Caldera(27°S) and Iquique (20°S) before continuing directly to Callao (Peru) (Darwin 1851, 1854).Expeditions conducted during the first half of the twentieth century were mainly dedicated tothe study of the local biodiversity. One of the most important expeditions during that time, theLund University Chile Expedition in 1948–1949, explored the Chilean coast between Iquique andthe Magellan Straits, but of the 277 stations visited, only 79 were located in northern and centralChile (Brattström & Dahl 1951). Only during the last half of the twentieth century have concentratedresearch efforts been directed toward the oceanography and ecology of the HCS in northern Chile(e.g., Gallardo 1963 and many others).While those initial studies have provided important information on the description of speciesdistribution and abundance in the HCS along the coast of Chile, research during the last quarterof the twentieth century became much more process oriented (Castilla & Largier 2002, Escribanoet al. 2004a,b, Montecino et al. 2005 and citations therein). In particular during the past decade,marine conservation has become an important topic in the marine sciences literature of Chile (see,e.g., Castilla 1996, 2000, Fernández et al. 2000, Fernández & Castilla 2000, 2005, Moreno 2001).Thus, as in other regions of the HCS (e.g., Pauly et al. 1989), research in the HCS along the Chileancoast has shifted from a description of taxonomy and patterns to the examination of processes,which has also resulted in an increasing trend of interdisciplinary studies, in particular betweenecologists and oceanographers.Oceanographic conditions in the southeastern PacificThe HCS is the equatorward-flowing, eastern portion of the basin-scale southeast Pacific anticyclonicgyre, bounded to the north by the equatorial current system and to the south by the WestWind Drift (WWD). The HCS is one of the four major global EBCs, characterised by dominantequatorward alongshore wind stress, offshore Ekman transport, coastal upwelling of cold, nutrientrichsubsurface water and highly productive fisheries (Hill et al. 1998). The narrow continentalshelf and meridionally oriented coastline of South America allow efficient transmittal of atmosphericand oceanographic signals imposed from both lower latitudes through the equatorial current systemand from higher latitudes where increasing seasonality in both wind forcing and oceanic response201
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