TEACHING and educating people on the importance of conserving scalloped hammerhead sharks will help raise awareness about the protection of endangered species — particularly species in Fiji.
A statement by the University of the South Pacific, School of Marine Studies said the recent and sharp decline in shark populations world-wide generated considerable interest in shark biology, ecology and particularly in understanding and characterising critical habitats for reproduction and survival such as nursery areas.
USP Marine Studies head of school Professor Ciro Rico said the density of scalloped hammerhead shark pups born in the Rewa Delta was the largest documented by science.
Prof Rico and his team from the university reportedly confirmed to The Fiji Times the decrease in shark populations worldwide was alarming.
He said sharks and stingrays were the most vulnerable to overfishing and also because they had long life spans. Many species produce live-bearing young such as the scalloped hammerhead shark — with low fecundity.
Endangered hammerhead females give birth to anything between 15-30 pups every two years.
Prof Rico said they hoped to identify critical survival areas for endangered hammerheads in Fiji.
He said a scientific documentation of the importance of the Rewa Delta as parturition and possibly as nursery ground for scalloped hammerhead sharks would be published. Hammerheads were listed as endangered species by IUCN. Hunted and killed for their fins by pelagic longline fishing vessles.
“Scalloped hammerhead sharks (Sphyrna lewini) were among the most globally threatened cartilaginous fish species and were known to use coastal embayment and estuaries for parturition and as juvenile nursery ground,” Prof Rico said.
“What we discovered is that every year between December and March, a large number of females, probably from 1000 to 2000, come into the nursery ground to give birth.
“We also know through DNA analyses of kinship that about the same number of males take part in the preproduction of each year’s cohort, but males do not come to the Rewa Delta during the parturition season, only females” he added.
Pro Rico said the team captured hammerheads between September 2014 and March 2016 before later released. A total of 1054 sharks, including 101 recaptures out of the 796 individuals tagged, in an area of approximately six square kilometres. Using DNA analyses, they also confirmed for the first time in any shark species that these pups were produced by at least 500 females and 500 males.”
Prof Rico said despite the identification of several threats to the decrease in shark’ populations, the lack of knowledge about the population status of most shark species could hinder the successful development and implementation of conservation and management plans.
