Tourism diving/swimming impact on a non-reproductive rockery of Southern sea lions.

COSCARELLA, M.; DANS, S. L.; CRESPO, ENRIQUE ALBERTO

Setubal

Congreso; 27th. ANNUAL CONFERENCE OF THE EUROPEAN CETACEAN SOCIETY; 2013

This work evaluates the influence of tourism boats and divers on the dynamic of a non reproductive rockery of Otaria flavescens. Data were gathered at Punta Loma, Chubut (42 °48' S, 64 °53' O) between June 2011 and February 2012. Fixed time censuses were carried out once a week at least three times a day, and additional censuses were carried out when a boat with divers was spotted near the rookery. Number of sea lions classified by age category, number of boats, number of divers and swimmers and distance from the rockery to the boat were gathered. The effects of these variables on the number of sea lions were assessed adjusting GAMMs, modeling variance heterogeneity and autocorrelations, using as response variables the total number of sea lions on the rockery and the number of adult males. Models were selected using AICc . Total number of individuals was affected mainly by the time of the day and date of census, varying daily and seasonally; increasing from February to September. The only two other variables influencing the number of sea lions were the number of swimmers (snorkeling) near the rockery and the number of boats, although these were weakly correlated. Adult males behave very different, and also the time of the day and date were the major factor influencing it’s dynamic. The other variables are not detected as influential, with the exception of the number of females in the rockery. The tourism related variables present a minimal influence on the rockery dynamic when compared with natural (ie: seasonal and daily) fluctuations.