2014 Feb Whale shark sampling in La Paz, Mexico –

Mike from Dinsdale lab went to La Paz, Mexico for Whale shark sampling with Dr. Deni Ramirez, founder of the organization Tiburon Ballena Mexico (Whale shark Mexico). See address below for more information about Dr. Ramirez’s work with Whale sharks in La Paz.




Whale sharks (Rhincodon typus) are the largest sharks (and fish) in the ocean, reaching lengths of up to 20 m (60 ft) (1). These animals are globally distributed at the tropics and subtropical latitudes. Despite their large size, we know relatively little of whale shark biology. For parts of the year, juveniles and pregnant females will occupy shallow, productive embayment’s, feeding primarily on plankton (2). For the remainder of the year, whale shark whereabouts are largely unknown. For instance, we do not know where whale sharks engage in reproductive behaviors. We do know however, that whale sharks exhibit two functional, distinct populations: an Indo-Pacific and Atlantic population (3). This suggest whale sharks have minimal migration between the two regions, at least from a mating perspective.

In La Paz, Mexico, at the southern end of the Baja Peninsula, whale sharks congregate between the months of October and March. Juvenile males and females come to this site year after year until they reach maturity (approximately 7 meters for male whale sharks and 9 for females in the Pacific (4)). Through collaborations with Dr. Deni Ramirez of Whale Shark Mexico, we aim to expand our understanding for microbial dynamics on the skin of the largest shark. The La Paz subpopulation lends itself well to study due to the predictability of the sharks to this site each year, their relative close proximity to town, and the well documented return of several individuals (identified by unique spot patterning). We are excited to continue this collaboration with Dr. Ramirez in the near future.

  1. Chen, C.T., Liu, K.M. and Joung SJ. 1997. Preliminary report on Taiwan’s whale shark fishery. TRAFFIC Bull 17:53–57.
  2. Martin RA. 2007. A review of behavioural ecology of whale sharks (Rhincodon typus). Fish Res 84:10–16.
  3. Vignaud TM, Maynard JA, Leblois R, Meekan MG, Vázquez-Juárez R, Ramírez-Macías D, Pierce SJ, Rowat D, Berumen ML, Beeravolu C, Baksay S, Planes S. 2014. Genetic structure of populations of whale sharks among ocean basins and evidence for their historic rise and recent decline. Mol Ecol 23:2590–2601.
  4. Ramirez Macas D, Vázquez-Haikin A, Vázquez-Juárez R. 2012. Whale shark ( Rhincodon typus ) populations along the west coast of the Gulf of California and implications for management. Endanger Species Res 18:115–128.

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