Estimations of the tourist carrying capacity of whale sharks (Rhincodon typus) in the Bay of La Paz, B.C.S. Mexico

A high number of juvenile whale sharks (Rhincodon typus) gather to feed in a predictable manner at the Bay of La Paz, Mexico,. The analysis of fresh injuries carried out from 2009 to 2016 shows that each year between 35% and... [ view full abstract ]

A high number of juvenile whale sharks (Rhincodon typus) gather to feed in a predictable manner at the Bay of La Paz, Mexico,. The analysis of fresh injuries carried out from 2009 to 2016 shows that each year between 35% and 64% of sharks are harmed by boats. This problem originated by an increase on demand for tourist activities has generated the need to take specific management measures. A numerical model was implemented for the calculation of Tourist Carrying Capacity (TCC). 73 field work trips were made between 2015 and 2016, in order to record the number of boats making the whale shark activity and the good practices of the rules. For this study, the average number of photo-identified sharks per month was taken as abundance, using historical data from 2007 to 2016. The calculation of TCC was carried out monthly because shark numbers vary throughout the season, presenting a high in December with a range of 8 to 53 photo-identified sharks and an average of 31 sharks. Data shows a range from 6 to 17 boats at the same time. However, based on this study, modifications were made to the management plan and the precautionary principle was followed, starting with 14 boats at the same time. A tourist season that covers the months of October to April is suggested. It will be discussed how the management of this species must take into account the seasonality and abundance of sharks and the challenges to conservation that they entail.