Coquimbo - Chile 14- 17 October 2007 ABSTRACTS ABSTRACTS Keynote Lectures Symposium Contributions Oral Contributions Poster Contributions 21 Coquimbo - Chile 14- 17 October 2007 KEYNOTE LECTURES LIFE CYCLES AND POPULATION DYNAMICS OF HOLOPLANKTONIC COPEPODA IN THE HUMBOLDT CURRENT SYSTEM Escribano, R. Center for Oceanographic Research in the eastern South Pacific (COPAS), Departamento de Oceanografía, Universidad de Concepción, Chile. E-mail: [email protected] Crustacean holoplanktonic Copepoda are the main grazers in the pelagic system of the world ocean and a key component for the carbon cycling and functioning of the ocean biological pump. In the last few decades, our knowledge on life histories and population dynamics of key copepod species of the Humboldt Current has substantially increased, enhancing the understanding of phenological responses to environmental forcing. A key process modulating population dynamics and life history traits of copepods is the wind-driven coastal upwelling. Upwelling fuels primary producers, providing a rich variety of autotrophic and heterotrophic organisms which are both efficiently utilized by copepods as food supply. However, upwelling also exerts a strong influence on physiological adaptations, because of a highly heterogeneous coastal environment over the space and time. Copepods ought to adopt mechanisms to cope with highly patchy food resources, strong horizontal and vertical gradients in temperature, density and dissolved oxygen and constraints imposed by a very shallow oxygen minimum zone, which may restrict their habitat in the vertical plane. Copepod populations have certainly succeeded in evolving adaptations to upwelling forcing, although trade-off processes are certainly occurring, such as non-linear interaction with prey organisms and strong predation pressure by carnivorous zooplankton and fishes. These two processes may modulate copepod recruitment and mortality and so influencing patterns of population growth. In this work, the main features of population dynamics of dominant species of copepods of the Humboldt Current and their adaptations to upwelling variation are revised, aiming at gaining an integrated view of plankton dynamics of pelagic crustacean in highly productive coastal upwelling systems. PARENTAL CARE IN BRACHYURAN CRABS: THE EFFECTS OF BODY SIZE AND TEMPERATURE Fernández, M. Estación Costera de Investigaciones Marinas & Center for Advance Studies in Ecology and Biodiversity, Dpto de Ecología, Pontificia Universidad Católica de Chile, Santiago, Chile. E-mail: [email protected] Although the ecological pressures that select for parental care in aquatic and terrestrial environments may be similar, the constraints imposed by the environment to aggregate the embryos and to care them differ, as do the patterns of investment in parental care. The constraints to brooding in the ocean seem to be related to the physical characteristics of aquatic environments. Several lines of evidence suggest that oxygen concentration is a limiting factor. In fact, constraints to supply oxygen to aggregated embryo masses is one of the mechanisms invoked to explain the allometric relationship between the capacity to produce eggs and the capacity for incubation. This capacity, in turn, might be affected by temperature, since oxygen demand of the embryos increases with temperatures. I studied the constraints to supply oxygen to aggregated embryo masses and the associated costs, using as model Brachyuran crabs (an exception to the rule) of different body sizes. I also evaluated the effect of temperature. Results show that the cost of brooding is insignificant at small body sizes, and extremely high at large body sizes, pattern that seems to affect egg production and limit parental care at large body size. Brooding behavior and the cost of oxygen provision increases with temperature while reproductive output decreases, suggesting a tradeoff between investment in eggs and the cost of providing oxygen to the embryos at different temperatures (latitudes). These patterns may also apply to other marine invertebrates since oxygen limitation during early development occurs in other brooding species, and might have consequences on population dynamics and species distribution. In fact, recent studies along the coast of Chile show that sea surface temperature explain the decrease in diversity of brooding species at low latitudes (high temperatures) among Brachyuran, Anomuran and Mollusc species. These results relate the mechanisms constraining parental care in the ocean with the consequences on population dynamics and biodiversity patterns. Fondecyt 1060489, FONDAP-Fondecyt grant 1501-0001, Pew Foundation 22 Coquimbo - Chile 14- 17 October 2007 KEYNOTE LECTURES DEEPWATER DECAPODS AND THEIR FISHERY ALONG THE PACIFIC COAST OF LATIN AMERICA Wehrtmann, I.S.1, Arana, P.M.2 1 Centro de Investigación en Ciencias del Mar y Limnología (CIMAR) and Escuela de Biología, Universidad de Costa Rica, San Pedro, San José 2060, Costa Rica; 2 Escuela de Ciencias del Mar, Pontificia Universidad Católica de Valparaíso, Casilla 1020, Valparaíso, Chile. E-mail: [email protected] A considerable number of marine shallow water fisheries show clear signs of overfishing. Due to this situation, scientific and commercial efforts have increased during the last few decades to gather information concerning the ecology and fishery- biology of deepwater resources. Decapod crustaceans represent an ecological and economical important portion of the deepwater fisheries in the world. Regarding the Pacific of Latin America, especially Chile and Costa Rica are commercially exploiting several decapod species inhabiting waters below 200 meters. Here we present a brief overview of our current knowledge about the biology of the following commercially important deepwater decapods from the Pacific coast of Latin America: Solenocera agassizii, Haliporoides diomedeae, Campylonotus semistriatus, Heterocarpus reedi, H. vicarius, H. affinis, Pleuroncodes planipes, P. monodon, Cervimunida johni, Lithodes antarcticus and Chaceon chilensis. During the second part of our presentation, we present currently used fishing techniques and fishery statistics of these decapods in Pacific Latin America, focusing on statistics concerning Heterocarpus spp.. By-catch is a serious and well known problem associated with bottom trawl fisheries. We present the by-catch composition of shrimp fisheries in Costa Rica and Chile, and discuss problems associated with by-catch and discard rates in some deepwater shrimp fisheries in the area. Finally, we describe current management plans for selected commercially exploited deepwater decapods in Pacific Latin America, highlight their strengths and weaknesses, and compare these strategies with those implemented in similar decapod fisheries outside of Latin America. 23 Coquimbo - Chile 14- 17 October 2007 SYMPOSIUM CONTRIBUTIONS INTRASPECIFIC VARIABILITY: A NEGLECTED FRONTIER IN THE LARVAL BIOLOGY OF DECAPOD CRUSTACEANS Anger, K. BAH/AWI, Helgoland, Germany. E-mail: [email protected] Developmental patterns in decapod crustaceans are commonly considered as canalized, i.e. as constant species-specific traits, which are relevant for phylogenetic analyses. However, there are numerous examples of intraspecific variability in larval morphology and developmental pathways, especially in caridean shrimps. This “background noise” has widely been ignored, although it may affect conclusions drawn from interspecific comparisons in the contexts of taxonomy and life-history evolution. Intraspecific variability in the number and morphology of successive stages also impedes the identification and staging of field-collected larvae, impairing studies of their ecology, growth, dispersal, and recruitment. On the other hand, experimental studies of the extent and causes of developmental variability under controlled conditions may provide new criteria (in addition to rates of survival, moulting and growth) that can be used for the evaluation of larval fitness in relation to different environmental conditions: Morphologically stunted forms occurring after a given number of moults may indicate sublethal physical or nutritional stress prevailing during the period of larval development, while rapid morphogenesis should reflect favourable conditions. Variability in developmental patterns may also result from carry-over effects of previous conditions persisting from the embryonic through the larval phase. Similarly, variations in larval traits may affect the recruitment success and postmetamorphic fitness of benthic juveniles. Plastic developmental traits are therefore potentially relevant for population dynamics, distribution patterns, and the formation of metapopulations in benthic species with complex life cycles. Moreover, the testing of cultivation techniques, especially in shrimp aquaculture, should benefit from the introduction of additional evaluation criteria. In conclusion, intraspecific variability remains a frontier in larval biology that should no longer be neglected. GUIDELINES FOR THE EXPLOITATION OF A VIRGIN RESOURCE IN THE FRAMEWORK OF A ROBUST HARVEST STRATEGY Barón, P.J.1,2, Leal, G.A.1, Dellatorre, F.G.1, Parma, A.M.1 1 Centro Nacional Patagónico (CONICET) Argentina; 2 National Technological University. E-mail: [email protected] Exploitation of commercial true crabs along the Atlantic coasts of Argentine Patagonia has not acquired the status of a formal fishery yet. Although two commercially promising resources, the