A Hammerhead Shark named Sylvia

Given the fact that Cocos island is known to have one of the World’s greatest congregation of sharks, naming a single specimen can be close to impossible. Not unless that particular shark has a distinct feature that is unique only to itself. Like for instance, let’s the case of a popular killer whale featured in an box office adventure movie where you can easily identify it through its curved and bent dorsal fins.

In the case of Sylvia the Hammerhead Shark, it has no distinct body markings like spots, stripes or any body deformity. But how were they able to sort out a single shark among its huge population and give it a name?

Shark Tagging

If you will rely on both body markings and anatomical deformities as what they are doing with identifying specific individuals of whalesharks and manta rays, then you will be having a hard time doing this. Instead of bench marking these body features, scientists use acoustic transmitters. This small device is embedded in the sharks body through a spear gun or harpoon and targeted just under the dorsal fin. Although it may initially stung the shark when harpooned, it will leave no long term damage.

But scientist are not doing this just for the sake of naming a specific shark individual. Once embedded, this device will emit a signal where it can be track on board via a monitor. Conducted just this year, this shark tagging expedition was participated by a collaboration of scientists from CREMA Costa Rica, Fins Attached Marine Research and Conservation, Ocean First Foundation and Mission Blue. They were able to tag 5 adult female hammerhead sharks and were monitored using 7 acoustic receivers. Expected results of this study will allow scientist to understand the swimming patterns of hammerhead sharks including their migration pathway. In fact, they are expecting that the results of the study will fully support the establishment of “Protected Swimways” for sharks and other migratory species. This area will cover the Galapagos Island of Ecuador, Malpelo Island of Colombia and Cocos Island of Costa Rica where these islands are known to house a large population of sharks.

And so far, the initial results are promising.

Of all the names, why Sylvia?

First of all, scientist are certain that the hammerhead sharks they had tag were females by verifying that it has no claspers which is the male reproductive organ. Among the five sharks they have tagged, they dub the first shark and named it Sylvia. But why Sylvia? Why not Dennise, Melchora, Elsa, Gregoria and other female names? Or perhaps Marjorie?

Scientists, staff and crew on board the shark-tagging expedition named the shark after Dr. Sylvia Earl of the US based Marine Conservation Organization called Mission Blue. Dr. Earl, who leads the expedition, has dedicated here entire life in protecting sharks and other marine wildlife and has been one of the key persons in lobbying Governmental Institutions in establishing Marine Sanctuaries such as the Proposed Protected Swimways of Malpelo, Galapagos and Cocos Island.

Reference

The Costa Rica Star: news.co.cr

CREMA Costa Rica: cremacr.org

NOAA: www.nefsc.noaa.gov

https://www.youtube.com/watch?v=fvRjpG8n-RM&feature=youtu.be

Video courtesy from CREMA CREMA