Utilization of AVHRR and SeaWiFS satellite images in Studies about the distribution, abundante and habitat use by marine mammals in San Matias Gulf, Patagonia (Argentina)

SVENDSEN, GUILLERMO; WILLIAMS, GABRIELA NOEMÍ; DANS, SILVANA; GAGLIARDINI, DOMINGO ANTONIO; CRESPO, ENRIQUE; GONZÁLEZ, RAÚL

Puerto Madryn

Workshop; SAC-D/Aquarius Workshop; 2008

CONAE

The San Matías Gulf (SMG) constitutes the largest of the north-patagonian gulfs, and several of their environmental and biological properties allow us to consider it as a marine ecosystem unity. This gulf presents a variety of environments, habitats and a rich biological diversity, supporting fishing exploitation and other human uses of coastal areas (tourism, industry, ports). One of the most conspicuous oceanographic features of the gulf is the formation of a frontal system during spring-summer months, which separates the gulf into two water masses: the northern, warmer and more saline, and the southern, colder and less saline. Typically, dense plankton accumulations occurring in the frontal areas attract feeding aggregations of fishes, birds, marine mammals as well as fishing vessels. Recent studies allowed to know that the SMG frontal system is an area of high productivity, where intensive fishing trawl occurs during the warmest months. However, the presence of marine mammals related to this frontal system has not been studied yet. In this context, the main goal of our work is to study the marine mammal distribution on SMG, and its relationship with environmental features, like sea surface temperature, salinity and chlorophyll-a, and with special reference to the frontal system. We use environmental information provided by direct measurements of chemical and physical water parameters, and by satellite images of sea surface temperature and primary productivity, obtained from AVHRR and SeaWiFs sensors, respectively. These data are applied: a) to a priori design sighting surveys (aerial and vessel) directed to estimate the distribution and abundance of marine mammals, and b) to analyze the relationship between environmental parameters and marine mammal’s distribution. In this work we present the advances obtained during the initial phase of this study and discuss the feasibility of using satellite information in future studies on the distribution and habitat use of marine mammals in the gulf.