Sharks and rays of PNG
PAPUA New Guinea is a global biodiversity hotspot, loved for its birds-of-paradise, tree-kangaroos, figs, rhododendrons and umbrella trees. The area is also a region of exceptional marine biodiversity and home to many species of sharks and rays, including a number of species recently described as new to science.
Working with PNG’s National Fisheries Authority, Will White of CSIRO’s Australian National Fish Collection and colleagues have authored a new field guide describing the biodiversity of the sharks and rays of PNG, many of which hold significant cultural value in PNG as well as being a valuable resource.
“Fishing is an important source of food and income for all coastal communities in PNG,” White says. “Like tuna and prawns, sharks are an important export commodity. Our field guide covers the taxonomy, biology, distribution and abundance of PNG’s sharks and rays and provides an important capacity building tool for PNG’s fisheries and conservation agencies.”
The field guide also supports sustainable fishing of sharks and rays. Sharks are slow growing, vulnerable to overfishing and at risk from practices such as harvesting fins, which are prized in China for making shark-fin soup. Overexploitation in some countries has led to dramatic declines in shark populations.
“Supporting developing countries to manage shark and ray fisheries is important,” White says. “PNG has a substantial marine territory in an area of high biodiversity value, which needs to be balanced against the livelihoods of people who may have few alternative options for employment and industry.”
Discovering new species
Highlighting the scarcity of scientific knowledge of the biodiversity of sharks and rays in PNG, the researchers described many new species of sharks and rays ahead of publishing the book.
Discovered in the Kimberley and Kakadu in Australia as well as in PNG, Urogymnus acanthobothrium is a recently described species of giant whipray that occurs in both brackish and marine waters and reaches up to 1.6 metres wide across its disc.
A new species of guitarfish, the Papuan Guitarfish (Rhinobatos manai) was described based on just a single specimen collected during deep water surveys by a French research vessel in 2014. The specimen was, an adult male of 73 cm length, was named in honour of Dr Ralph Mana of the University of Papua New Guinea in recognition of his work on deep water fishes of the region.
Surveys of catches of sharks and rays also turned up new sightings of known species.
“Our surveys of artisanal fishers in the Daru area resulted in the local rediscovery of two threatened species of river sharks, Glyphis garricki and Glyphis glyphis,” says White. “These species are also known from northern Australia. These are the first confirmed sightings of these species in PNG since the 1960s and 1970s.”
Working alongside the local community
“The assistance provided by fishers and villagers during surveys was invaluable and provided important insights into how the various shark and ray species are caught and utilised in PNG,” White says.
A total of 19 PNG fisheries observers were deployed on commercial fishing vessels during this project, providing a large amount of biodiversity information. Coastal fisheries surveys in areas such as Daru, New Ireland, Bougainville, Manus Island, Milne Bay and the Sepik River also provided important information.
“We also worked with the dive community in PNG and were able to confirm a number of new records of species from images supplied by divers during the project,” White says. “The grey nurse shark [Carcharias taurus] was confirmed from PNG based on images from Milne Bay by Bob Halstead and the pygmy devilray [Mobula kuhlii] was confirmed based on images provided by Dietmar Amon from Lissenung Island in New Ireland.”
Natural history collections also provided an invaluable insight into the biodiversity of sharks and rays in PNG. The team visited 14 museums around the world to examine specimens from PNG waters. The oldest specimens were two stingrays found in the Muséum National d’Histoire Naturelle in Paris, which were collected from PNG in 1825.
The field guide
Sharks and Rays of Papua New Guinea is the first dedicated field guide to the sharks and rays of PNG. The four year project to assess the shark and ray resources of PNG was funded by the Australian Centre for International Agricultural Research (ACIAR), CSIRO and the PNG National Fisheries Authority. It brings together new information as well as information from scientific publications and other disparate sources, making it easily accessible.
The work built on the legacy of Ian Munro, who founded the CSIRO fish collection that ultimately became the Australian National Fish Collection. He undertook most of his early work on the fishes of New Guinea, including his monumental Fishes of New Guinea in 1967.
Under ACIAR’s partnership model, CSIRO scientists are continuing their work in PNG to help build scientific capacity in the fisheries sector.
Sharks and Rays of Papua New Guinea can be downloaded for free or purchased in hard copy from ACIAR.