Whale Shark Expedition - Cendrawasih Bay  E-mail
Science & Conservation
Written by Kenneth Wiedenhoeft   
Fri, 2 Oct 15 01:46

We have just finished our latest adventure, a trip tagging whale sharks.

 

Indonesia's Cenerwasih Bay is a place where whale sharks come to feed on small fish falling from the nets of “Bagans”. “Bagans”are boats of about 10 to 15 meters(33 to 49 feet) long and larger with outriggers. Underneath there are large nets that are lowered at night, then bright lights are turned on to attract fish. At predetermined times the lights are turned off and the nets raised along with the fish trapped within them. As the nets rise small fish overflow or escape through holes in the nets. Whale sharks normally feed mostly on plankton but began coming to feed on those fish. Eventually the fishermen began feeding them additional fish and the added source of food available has attracted a larger number of sharks and established a place where tourists can reliably find whale sharks to interact with. We have dove/snorkeled with as many as 7 at one time. They are friendly and appear to actually enjoy people interacting with them.

 

There is still much unknown about whale shark behavior and migration habits, therefore in an effort to gain further knowledge some are being tagged with electronic devices that record such data as depth, temperature, time, etc

 

There are currently 3 types of tags being used. The first is attached to the body near the dorsal fin by injecting a small anchor under the skin that is connected to it. That type must be monitored by someone approaching the whale shark and reading data with a device similar in function to a bar code reader. 

The second type is also attached near the dorsal fin but is designed to break free after a programmed length of time. Once free, it will float to the surface and upload its stored date to scientists via the satellite. 

 

The third type is new and employs the latest technology to store more data at higher resolution. It has batteries that keep it operating for 6 months. When the whale shark occasionally surfaces, a set of sensors detects that the fin is out of the water, the tag's transmitter turns on, and the stored data is uploaded to a satellite. It was this third type that was installed during this trip.

 

The installation of tags during our trip was performed by a team of local Indonesian scientists from “Conservation International”, University of Papua, and the National Park organization and was led by Doctor Mark Erdmann from “Conservation International”. Completing the task required coordination with the fishermen. When a whale shark appeared, it was lured into their net, the net was raised to near the surface, and the operation began. The dorsal fin of the shark has no nerves so attaching a tag causes no pain. They lay calmly while 4 holes were drilled through the fin and bolts attached the tag. Once tagged they were assisted with clearing the net and they swam away unconcerned, looking for more to eat. A total of five were successfully tagged.

 

It is always a very enjoyable experience interacting with these beautiful animals but this time it was an exceptional experience.

Add a comment

 
CI Report From Mark Erdmann - Expedition Leader  E-mail
Science & Conservation
Written by Dody Wiedenhoeft   
Fri, 2 Oct 15 00:27

Report from doctor Mark Erdmann, the expedition leader for recent CI expedition:

 

"My organization (Conservation International) has been working with the Ministry of Marine Affairs and Fisheries to conduct satellite tagging of both manta rays and whale sharks to better understand their movement patterns within Indonesia - particularly to get a handle on whether they are migrating via "hotspots" of hunting activity (such as Lamakera and Tanjung Luar in NTB) and if they are in fact frequently leaving Indonesian waters altogether. We anticipate soon being able to release a report on the results of the manta ray tagging to date (in Raja Ampat, Komodo, Nusa Penida and Sangalaki) that may be of interest to many of you - hopefully within next 1-2 months.

 

In the meantime, the whale shark tagging in Cenderawasih and Triton Bays has been more challenging, as the towed satellite tags have tended to get "snagged" when the sharks swim close to the bagans and their nets. Indeed, if you look at the state of the art for shark satellite tagging around the world with everything from Great Whites and Tigers to Blues and Blacktips and Caribbean reef sharks, the standard approach is to use "fin mount" satellite tags whereby the satellite tag is actually mounted directly on the dorsal fin (bolted through it) - which ensures the tag doesn't cause significant drag or get tangled. To do this, the sharks are usually caught by long-line, pulled up to a research boat, and then either anaesthetized or turned upside down to put them into a state of "tonic immobility" before the researchers drill holes through the fin and mount the satellite tag. The dorsal is generally believed to not be innervated, so there is reportedly no pain associated with this mounting technique. At any rate, this approach has never been done with whale sharks previously, as it is of course highly unlikely to catch them on a long line and they are far too large to pull up on a boat deck. However, we recently were successful in working with the BBTNTC Cenderawasih National Park authority and Ministry of Fisheries to deploy 5 fin-mount satellite tags on Cenderawasih whale sharks, utilizing the fact that the sharks are frequently caught in the bagan nets at night and are very docile and subdued until they are released from the net. We operated on 5 sharks that were caught in the nets at night, and these five sharks are now happily swimming around Cenderawasih and transmitting daily data on their whereabouts and their diving behaviour. Not surprisingly, they have all remained in the Kwatisore region since tagging last week. 

 

At any rate, I wanted to let you know that there are now 5 sharks with these fin-mount satellite tags on them, in order that you know to expect this if you go to Cenderawasih and your guests ask about this. We plan to leave these tags on the sharks for a year or more (depending on how battery life is looking and if they are still resisting fouling), after which we'll remove them. We intend to provide regular updates on their movements on the www.birdsheadseascape.com website

 

Best,

 

Mark"

Add a comment

 
Diving with CI  E-mail
Science & Conservation
Written by Kenneth Wiedenhoeft   
Thu, 1 Oct 15 23:43

Our last trip was a charter by Conservation International with Mark Erdmann, Gerry Allen, Ronald(a local C.I. Employee), and Sarah Lewis(a Manta Ray specialist) on board. The planned itinerary was to Kri Island first then to Ayau Island via Eagles Rock. Several days were to be spent there. Sarah and Ronald were to research Manta Rays while Mark and Gerry searched for new fish species. From there it was to Kwatasori for tagging of whale sharks. 

 

We first sailed to Kri Island where a research meeting was held with Max Ammer then we started to depart for Eagles Rock only to anchor in front of Sorrido Bay. For the next 2 days our guests dove in the Kri area.  

 

From Kri we skipped plans for Eagles Rock and sailed directly to Ayau Island. During the 3 days there Sarah and Ronald managed to tag a baby Manta while Mark and Gerry discovered a couple possible new fish species. 

 

On the 4th day, we departed for Manokwari in late afternoon amid worsening weather conditions. Swells parallel to out intended direction made sailing difficult but we managed to struggle on until midnight when conditions got much worse. Fearing for our safety we turned South traveling in the same direction as the waves and headed toward the North Eastern tip of Waigeo. That eliminated the severe rolling that had developed and we began to feel more comfortable. 

 

We rounded the tip of Waigeo about four o'clock in the morning. 

 

Daylight finally arrived and weather conditions began to improve as we continued South towards “Blue Magic” dive site. From there we headed west along the Southern side of Waigeo then North West toward “Eagles Rock” and along the Western side of Kawe Island toward Wayag. All went well until we hit the open stretch between Kawe and Wayag where wave conditions forced us to retreat back to the “Eagles Rock” area where we could spend the night in a small bay.

 

As we approached the area we stopped, dispatched the divers, and headed toward the bay.

 

In the meantime, the guests dove in the bay and at “Eagles Rock”. While at “Eagles Rock” Mark was watching some Mantas then turned around to see a 3.5 meter(11 feet) Tiger shark swimming toward him. He went into a defensive position thinking that it might be attacking but coincidentally the speed boat above started its motor and the noise scared the shark away. 

 

Soon after we traveled along the Eastern side of Kawe then around the corner to the bay near “One Tree Rock” to dive and spend the night. The next morning we sailed to Wayag, weather was much better. After spending the day at Wayag we headed South toward “Dayang” on the Northern coast of Batanta Island. We arrived early morning, the guests dove there, and early the next morning we rounded the Western tip of Batanta and stopped for a dive in a bay along the South coast. From there we sailed along the Southern side to the South Eastern tip and anchored for the night. 

 

Early the next morning we sailed to Sorong and ended our trip with a sigh of relief. It is one trip I am happy is over with.  The trip was declared a productive success. A manta ray was tagged, two new fish species were definitely discovered, and there were several possibly new fish species found.

Add a comment

 
Follow the Raja Ampat Expedition  E-mail
Science & Conservation
Written by Dody Wiedenhoeft   
Thu, 17 Nov 11 11:28

We are happy to say that we are currently supporting another great expedition with TNC scientists (The Nature Conservancy). We will be sailing away for the next few weeks with them. You can definitely follow their progress from the following link:

http://blog.nature.org/2011/11/follow-the-raja-ampat-expedition/

Add a comment