Shark Tagging

Sharks are fitted with acoustic tags, which emit a sequence of low frequency "clicks" that give each tag a specific audible ID number. These unique signals can be detected and recorded by special receivers.Sharks have to be 400-500 meter from one of the receivers to be recorded.

Sharks can be tagged externally, meaning on a fin, a method that allows tagged sharks to be tracked for a short period of time. Or the tag can be internal, meaning the tag is implanted into the sharks belly through a roughly 2 inch incision, these tags last for up to 10 years and are more suitable for long term studies, especially of shark movements around an island group as Palau.

To capture a shark a single baited hook is suspended from a large, anchored buoy that is monitored continuously. After some initial commotion, a captured shark will soon quieten down enough to be brought alongside the boat. 

When safe to do so, experienced research staff secure the shark with suspension ropes and carefully roll the shark onto its back, putting it into a sleep-like state known as ‘tonic immobility’.  A small incision is then made in the shark’s abdomen, the tag inserted into the body cavity and the incision closed with a few stitches.  At the completion of the minor surgery the shark is rolled over to wake it up.

Even though the process only takes a few minutes, great care is taken to keep the shark’s head and gills in the water so that it can continue to breathe during the procedure.  A plastic ID tag is attached to the dorsal fin as a visual record that the shark has been internally tagged. Details about the shark are recorded such as species, sex, length and a genetic sample is taken. Once the tagging process is complete, lines are carefully removed and the shark is released.

Micronesian Shark Foundation's shark tagging program includes tagging of sharks with acoustic and satellite tags, deploying acoustic loggers around Palau’s reefs, collecting measurements and DNA samples from tagged sharks.

In coordination with the Attorney General's office of the Republic of Palau, further information is obtained through DNA samples from confiscated shark fins.



Shark Counting Program

As part of our scientific research program the Micronesian Shark Foundation is collecting shark count data. This data is collected by dive operators in Palau and the program is now extending to other islands in Micronesia.

The data we collect at "special sites" includes information on the numbers of sharks sighted and their behavior patterns, broken down by species, gender and size. It also identifies other factors such as water temperature, visibility and number of divers underwater.

The information provided allows our scientific researchers an insight to specific shark behavior, for example the migratory patterns of Grey Reef Sharks in Palau and the best months to tag sharks. It also allows to identify irregularities in numbers and behavior related to weather and other natural phenomena.

As example, we observed that Grey Reef Sharks in Palau were changing their mating behavior, as we believe, based on water temperature and eventually seismic activities. While Grey Reef Sharks are normally mating during February and March. In 2012 we observed female grey reef sharks with fresh mating scars in August, showing that the sharks were mating in the month of August, changing their mating pattern, an unusual find. When we analyzed our data, we noticed that the water temperatures during February-April were below the normal. Also quite a few underwater seismic activities were occurring in our region during this time.

While the link between these factors and the shark mating season is not yet clear, it is through such data collection and analysis that we hope to come to a better understanding of these beautiful creatures. Our goal is to have as much data collected all over Micronesia to assist with our scientific research.

The Micronesian Shark Foundation is cooperating with dive shops all over Palau to collect shark data through it's shark count form, designed by Micronesian Shark Foundation founder Tova Harel Bornovsky, containing information on dive site, water conditions, kind of shark, site population pattern, gender and seasonality. Data sheets are compiled and processed by Dr. Mark Meekan.

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