Sparkle-Clean Sharks: thresher sharks practice good hygiene in the Philippines

As marine biologists continue to study the physiology and behaviors of sharks, we are learning more and more about these fascinating creatures and what we can do to protect them if it's not too late. Case in point:

Thresher sharks have been greatly depleted in number - caught for their fins and meat - which is disappointing over and above the obvious loss in population because it is a very unique species. The thresher shark's namesake elongated tail fin has been shown to be used as a hunting tool, slashing and stunning its prey. Diver encounters with thresher sharks have always been scarce as they often swim in deep, open waters and don't typically congregate in large groups.

However, off the northern tip of Cebu in the Philippines, a dive tourism business is growing based on the thresher shark. Apparently, a concentration of thresher sharks frequent a seamount there, which increases the opportunity for divers to see these beautiful sharks in the wild.

Researchers from U.K.'s Bangor University have been studying the behavior of these sharks in the Philippines and have recently published their findings in the journal PLoS One. According to the research team, the thresher sharks are frequenting the deep seamount to get a good cleaning. Residing at the seamount are a number of cleaner wrasses, a fish well-known for cleaning larger reef fish by picking away parasites and dead skin or scales. It seems that thresher sharks have caught on to the benefits of this hygienic service and will cruise close to the seamount, slowing down to half their normal speed and allowing the cleaner wrasses to give them a thorough once over.

The researchers have filmed this behavior, amassing over 1,000 hours of footage. They are quick to point out that mankind can have a disruptive effect on this symbiotic relationship - the seamount already shows evidence of dynamite fishing, a local commercial technique that literally destroys reef communities.

According to lead researcher Simon Oliver, “Our findings underscore the importance of protecting areas like seamounts which play an important part in [the sharks'] life strategy to maintain health and hygiene.”

Fellow researcher Dr. John Turner said, regarding their studies, “The work uniquely describes why some oceanic sharks come into coastal waters to perform an important life function which is easily disturbed by man.”

Thresher Shark: non-profit dedicated to shark's preservation

Speaking of sharks, here's a species you don't hear too much about and yet faces imminent danger: the thresher shark.

One of the more unusual and distinctive sharks due to its namesake elongated upper caudal fin or tail, it is believed that the shark might use its tail as a hunting device to stun schooling fish. The thresher shark is a popular seafood item in many forms - fresh, dried, salted - and so it's numbers have suffered (all three thresher shark species are listed as "vulnerable" by the IUCN).

Here's a post from the Shark Divers blog, discussing one of the few shark organizations devoted to the thresher shark. Based in the Philippines where considerable local fishing, commercial and, sometimes, illegal fishing takes place, this group has their work cut out for them.

Thresher shark research & conservation project

Of the myriad of shark conservation sites worth visiting, none come better then the Thresher shark research & conservation project.

We have been following this site for the past year and are always happy with the vibrant field updates, images, video and news.

Consider taking the time to get to know the team behind the Thresher shark research & conservation project.

Shark conservation efforts are hard enough to get traction with; in places like the Philippines, it's doubly so.

It's takes determination, good outreach, and a serious research program to make a difference.

Palau's Shark/Fishing Legislation: a reputation for conservation at risk

Palau has been a favorite dive tourist destination for many years because of its wonderful reefs and bountiful fishlife. And the island has, in the past, taken active steps to protect its shark populations with aggressive action against illegal shark finning operations. All of these efforts have contributed to the island's tourist economy and sound conservation policy.

But that all could potentially be undone with recent legislation that was introduced to both allow for commercial shark fishing and allow for the use of purse seining - a method that brings in a large amount of by-catch. Palau commercial fishing interests have been working with Philippine fishing groups and the combined influence on Palau legislators has produced SB8-44 (which drops the ban on shark fishing) and SB8-50 (which drops an export tax on fish caught by purse seining).

According to FinsMagazine, the collective result of the laws would be:

• To permit and encourage the killing of sharks in Palau’s waters
• To promote shark finning
• To promote fishing methods that according to Monterey Bay Aquarium “result in large amounts of unintended catch” including sharks, dolphins, turtles, rays and juveniles:
  http://www.montereybayaquarium.org/cr/cr_seafoodwatch/sfw_gear.aspx
• To exempt fishing companies from any export taxes on fish taken from Palau’s waters
• To make it practically impossible for Palau’s law enforcement personnel to successfully prosecute alleged violators in the courts
• To risk destroying Palau’s sustainable tourism industry
• To risk destroying Palau’s marine resources through unsustainable practices
• To gamble on all of the above for no apparent gain to Palau or Palauans.

This issue has made the rounds of several shark blogs recently, but opinions from everyone - from divers to land-bound ocean advocates - are needed to remind the Palau government that the negative impact on tourism and the island's marine ecology will ultimately outweigh the short-term gains in a working relationship with Philippine commercial fisheries.

Email the Palau Chamber of Commerce (pcoc@palaunet.com) and Belau Tourism Association (bta@palaunet.com) and the government tourism office Palau Visitors Authority (pva@visit-palau.com) .