WAMSI Node 3.2.1 - Diversity, abundance and habitat utilisation of sharks and rays - Acoustic data

Brief description

Elasmobranchs were tagged with acoustic tags and subsequently monitored with acoustic receivers (Vemco VR2, VR2W and VR3) moored on the seabed that constitute the Ningaloo Reef Ecosystem Tracking Array (NRETA). This array is part of the nationwide network of marine acoustic monitoring, the Australian Acoustic Tagging and Monitoring System (AATAMS).

A total of 96 acoustic receivers are deployed at Ningaloo Reef between Coral Bay and Tantabiddi.

A total of 56 acoustic tags were deployed on six species of sharks and three species of rays in the Ningaloo Marine Park in February 2008.

Data is accessible through the IMOS AATAMS website listed below.

Lineage

Statement: Elasmobranchs were tagged with acoustic tags and subsequently monitored with acoustic receivers (Vemco VR2, VR2W and VR3) moored on the seabed that constitute the Ningaloo Reef Ecosystem Tracking Array (NRETA). This array is part of the nation-wide network of marine acoustic monitoring, the Australian Acoustic Tagging and Monitoring System (AATAMS) A total of 96 acoustic receivers are deployed at Ningaloo Reef between Coral Bay and Tantabiddi. These are deployed as three curtains (Tantabiddi, Norwegian Bay, Coral Bay), three arrays (Mangrove Bay, Coral Bay, Stanley Pool), and three points of interest (Coral Bay). Arrays were deployed in November and December 2007, whereas curtains were deployed in February 2008. The Tantabiddi curtain comprises 7 receivers (10-96 m), the Norwegian Bay curtain 13 receivers (95-160 m) and the Coral Bay curtain 12 receivers (7-66 m). The array at Mangrove Bay consists of 50 receivers (1-47 m) and the Coral Bay array consists of 14 receivers (2-34 m). VR2 and VR2W receivers have been deployed on concrete filled tyres in shallow water (<25m) near the reef, or star pickets hammered into the sand, while in deeper waters (>25 – 200m) the units have been deployed on moorings lines with an acoustic release anchored by 120kg steel weights. The acoustic tags were Vemco V16s and V13s that were 35-62 mm long. Most tags were surgically implanted in the peritoneal cavity. The skin around the surgical site was sterilised with betadine spray. A small incision (1.5 cm long) was made in the ventral region forward of the cloaca in both sharks and rays. The tag was sterilised in Savlon and pushed through the incision which was then closed by 4-6 dissolving sutures. Some tags were coated in a paraffin and beeswax mixture in an effort to prevent transmitter rejection. Forceps and needle holders were sterilised between surgeries by submerging then in alcohol. Once the wound was closed it was sprayed with betadine. A mass dependent dose of Engemycine (Oxytetracycline 100 mgml-1) was administered intramuscularly via a 1 ml syringe and 26 gauge needle. The entire surgical procedure from capture to release took approximately 15 minutes. Some larger rays were tagged externally with V16s using a Hawaiin sling or modified speargun. The sex, total length (for sharks and shovelnose rays) or disc width (for stingrays) was recorded and a genetic sample taken from a fin clip. Elasmobranchs for acoustic tagging were caught by a variety of methods. Fishing was carried out both from the shore and from aluminium dinghy’s mainly in the vicinity of Mangrove Bay where there was a large array of listening stations in place. Sharks and rays were caught using gillnets, longlines, handlines, rod and line and dipnets. Gillnets were 25-50 m long, 2 m drop and had a stretched mesh size of 10 cm. They were set from the shore and any fish were removed as soon as they were seen to hit the net. Longlines were anchored at both ends and comprised 100 m of mainline with 10 hooks baited with mullet. Sets were of about 1 h duration. Longlines were deployed from a 5 m aluminum vessel. Fishing with handlines and rod and line was carried out both from the shore and from dinghy’s. Dipnetting was carried out in shallow water to capture rays that could be approached close enough.

Notes

Credit
JD Stevens, PR Last, WT White (CSIRO Marine & Atmospheric Research, Hobart) RB McAuley (Department of Fisheries, Government of Western Australia, Perth) MG Meekan (Australian Institute of Marine Science, Perth)