Gray Whale Abundance Increases for Second Year in 2012
The 2012 gray whale research team included Sergio Martínez A., Diana López A., Tabata Olavarrieta G., Laura Rodriguez J., and Mauricio Rodríguez A. They were joined in February by LSIESP co-director Dr. Steven Swartz, and assisted by Susana Tobar H., Flor Vázquez, Claudia Díaz, and Erandi Calderón Y.
The team began abundance surveys on January 18th and continued until April 15th, effectively covering the entire winter gray whale occupation of the lagoon. These surveys revealed that, like the 2011 winter, the overall number of gray whales utilizing the lagoon was greater than was observed between 2007 and 2010. The greatest number of adult whales was counted on February 22nd and included 205 single adults and 63 female-calf pairs (Fig. 1).
The late season gathering of females with their calves was originally documented during the 1978-1982 winters, but it was not seen in Laguna San Ignacio until 2011. The the comparison of photographs from Bahia Magdalena and Laguna San Ignacio will confirm if there is an exchange of gray whales between these two winter aggregation areas. Researchers also noted that the condition of the newborn calves looked very healthy, and very few “skinny” whales were observed in 2012. This suggested that gray whales are continuing to recover from the nutritional stress that was observed following the range-wide die-off the 1998-2000.
Counts of single whales reached a maximum of 205 whales on February 22nd (Fig. 3). In recent years (2007-2010) most gray whales were distributed in the areas nearest to the lagoon’s entrance and in the middle lagoon area, with few whales occupying the innermost northern areas of the lagoon furthest from the sea. However, in 2011 and again in 2012 gray whales were distributed throughout the entire lagoon, resembling the distribution patterns observed during the 1978-1982 time period. It is not clear why more gray whales are now utilizing more of Laguna San Ignacio than during the previous decade.