Scientists from King Abdullah University for Science and Technology and the Woods Hole Oceanographic Institute recently completed a six-year study of whale sharks around the Shib Habil reef in the Red Sea in Saudi Arabia.
Their findings, published in the latest issue of PLOS One, suggest that the Rope Reef may serve as a vital nursery for the endangered sharks. The team tracked the movement and residency of 84 sharks using a combination of three scientific techniques; visual census, acoustic monitoring and satellite telemetry. They found the aggregation to be highly seasonal, with sharks being most abundant in April and May, and that many of the sharks returned to the hot spot regularly year after year. The study also shows roughly equal numbers of male and female sharks using the site, something that could be unique to Shib Habil.
“Using the combined dataset, we can show somewhat conclusively that the aggregation meets all of the criteria of a shark nursery. This is particularly relevant given that Shib Habil is the only site in the Indian Ocean to regularly attract large numbers of juvenile females. Growing late-stage adolescents of both sexes into full adulthood is critical for sustaining a species. Management of critical habitats like Shib Habil and other aggregations will likely be vital for future whale shark conservation,” says KAUST graduate Dr. Jesse Cochran, lead author of the study.
According to the International Union for Conservation of Nature (IUCN), whale sharks are considered endangered, which means the species has suffered a population decline of more than 50% in the past three generations. The new data collected has enabled marine scientists to describe in great detail the residency behavior, seasonal philopatry, and spatial distribution of aggregating sharks, as well as to investigate the apparent sexual integration found at this site.