Strandings of southern right whales (Eubalaena australis) at Península Valdés, Argentina from 2003-2007

UHART, M.; ROWNTREE, V.J.; MOHAMED, N.; POZZI, L.; LA SALA, L.; ANDREJUK, J.; MUSMECI, L.; FRANCO, M.; SIRONI, M.; SALA, J. E.; MCALOOSE, D.; MOORE, M.; TOHUEY, K.; MCLELLAN, W. A.; ROWLES, T.

Santiago, Chile

Otro; The International Whaling Commission's 60th annual meeting; 2008

International Whaling Comission

More southern right whales die and strand each year on their nursery ground at Península Valdés, Argentina than anywhere else in the world. The Office of Protected Resources of the US National Marine Fisheries Service (NMFS) has provided support to the Argentine Programa de Monitoreo Sanitario de Ballena Franca Austral (PMSBFA) since 2003 to develop a better understanding of the health risks and disease susceptibilities of right and other baleen whales. Between 2003 and 2007, the PMSBFA team photographed, measured and collected tissue samples from 192 dead southern right whales including 170 calves, 15 adults and 7 juveniles.  Stranded calves ranged in length from 3.78-9.83 m, and the apparent mean growth rate, determined by calf length and estimated date of death, was 2.5cm/day.  Ten calves less than 4.24 m were recorded from June through November possibly indicating a broad birthing period. In relation to the last 30 years, calf deaths increased sharply in 2005 and 2007.  The population experienced an apparently severe mortality event in 2007 in Golfo Nuevo, the southern gulf of the Península Valdés.  Sixty calves died between October 4th and December 16th. Unfortunately, most calves died offshore and were in advanced states of decomposition when they stranded. With assistance from a team of specialists sent to Argentina by NMFS, a number of dead whales were thoroughly examined.  Though harmful algal blooms in the area are hypothesized to be linked to these deaths, no conclusive evidence was found in our investigations.