Sawshark satellite tagging

Understanding the movement of sharks is an important component of optimising conservation and management strategies. However, this information can be difficult to obtain for sharks that occur at depth. The common sawshark (Pristiophorus cirratus) is small, benthic shark and regularly occurs at depths of 40 to 500+ meters.  These sharks are frequently caught by Australian commercial fisheries as non-target catch. Despite their frequency of capture, very little is known about how far they can move and why. To better understand their movement ecology, we are tagging individuals using satellite telemetry, specifically pop-up satellite archival tags, to follow their movements.

This video captures the satellite tagging procedure of our fieldwork on the TV Bluefin off the northeast coast of Tasmania, Australia. Once an animal is captured, we obtain biological data such as the animal’s weight, sex and length. The animals are then tagged, which involves implanting a small dart into the muscle below the dorsal fin to anchor the tag to the shark. After tagging the shark is placed in a holding tank to recover. Once we are happy that the shark is fit and recovered from the tagging process, we deploy our remotely operated vehicle (ROV) to monitor the shark as it enters the water. This helps us to monitor any post-release responses of the released shark and observe any interactions it may have with wildlife, such as the very inquisitive seal that can be seen in this video! This particular shark was monitored to approximately 30 meters depth over 20 minutes. In time, the tag will release from the shark and transmit its archived data to a satellite network, thus providing valuable insights into where the shark has been.