Prior to this study only 12 aggregation sites had been identified globally. The team - which brought together researchers from King Abdullah University of Science & Technology (KAUST) and marine organisations in Massachusettes - used satellite tags to track the movements of 47 whale sharks in the red sea between 2009 and 2011. They discovered that most of these sharks congregated on a single aggregation site in the Saudi Arabian red sea.
They also observed that approximately 10% of the tagged whale sharks left the red sea, indicating potential global interconnectivity between populations.
What is particularly notable about this aggregation site is that the population was equally distributed between males and females. In other know juvenile whale shark aggregation sites, males dominate. Still, very little information regarding whale shark sex segregation is known.
The discovery of this 13th site adds valuable insight into whale shark activity. As with most large, pelagic animals little is known of whale shark life history. Population estimates vary greatly, putting the number somewhere between 27,000 and 476,000 adults worldwide. The researchers also found that the tagged sharks spent very little time at the surface making frequent dives to 500m and as deep as 1360m; owing to the fact that the majority of whale shark observations and tagging have occurred at the surface our current data may greatly under-represent actual whale shark behaviour.
The researchers report that there are no known fishing efforts for whale sharks by either Saudi Arabia or Djibouti although as with all marine animals which stray too close to the surface they are vulnerable to ship strikes.
Growing up to 12meters in length, the whale shark is the largest known fish, and like most "marine giants" is a suspension feeder with a predominantly vegetarian diet.
Whale sharks are listed as Vulnerable in the IUCN Red List. Like most shark species they can sometimes be taken as bycatch of the fishing industry, often by entanglement in nets, and are vulnerable to poaching for their fins and oil rich livers. However, in many parts of the world whale sharks generate valuable income for the tourism industry as swimming with whale sharks has become a popular holiday experience; in these areas whale shark protection tends to be upheld as many countries see the benefits live whale sharks can bring.
This study adds new insight into whale shark populations in the red sea and lends support for putting in place conservation measures for this whale shark population.
Breumen, M., Braun, D., Cochran, J., Skomal, G. and Thorrold, S. (2014) Movement Patterns of Juvenile Whale Sharks Tagged at an Aggregation Site in the Red Sea. PLOSOne http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0103536
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