Number of southern right whales Eubalaena australis and population trend in the neighbourhood of Península Valdés during the period 1999-2011 by means of aerial and boat surveys

CRESPO, ENRIQUE ALBERTO; PEDRAZA, SUSANA; DANS, SILVANA LAURA; COSCARELLA, MARIANO ALBERTO; SVENDSEN, GUILLERMO; DEGRATI, MARIANA

Buenos Aires

Workshop; Scientific Commitee Workshop on Right Whales; 2011

International Whaling Commissionn

Following severe historical depletion by commercial whaling, several breeding populations (Argentina/Brazil, South Africa, and Australia) of southern right whales have shown evidence of strong recovery, with a doubling time of 10-12 years. The other breeding populations are still very small, and data are insufficient to determine whether they are recovering. Based on the need of having a quick and cheap methodology to estimate relative abundance and population trend we developed a method based on direct counts of whales on the coastal zone. The main objectives are: 1) to develop the method, 2) to estimate relative abundance in the monitoring zone every year, 3) to estimate rate of increase, 4) to document changes in the distribution of whales through time, and 5) to study the seasonal pattern of arriving and departing of whales in the Peninsula Valdés Area.