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ONGOING RESEARCH Latest
published research See also: NEW South
Africa January 2006 Our team is investigating the Molidae through two complementary approaches–pop-off satellite archival tagging of individuals and genetic analysis of global populations. TAGGING Our tagging work involves special tags called pop-up archival transmitting (PAT) tags. PAT tags are secured using a plastic anchor inserted at the posterior base of the dorsal fin. While attached, the tag records and logs temperature, depth and light intensity. From light intensity, day length and local noon are calculated. This information in conjunction with sea surface temperature measurements is used to document location. After a pre-programmed time, the tag releases floats to the surface and uploads its data to satellite. Thus, daily information on movements and behaviors are obtained without having to relocate either the fish or tag. Should the tag release early or the fish die and sink, the satellite tag will automatically surface and initiate transmission. (For more information on satellite tags see http://www.wildlifecomputers.com/Satellite%20Tags/PAT.htm) Our team has tagged Mola mola off San Diego (California), Capetown (South Africa), Kamogawa (Japan) and Queensland (Australia). We have also tagged Masturus lanceolatus off Hua Lien (Taiwan). To date, six tags have reported and we are in the midst of analyzing our data. We’ll be posting our exciting results soon so stay tuned. The sunfish have some dark secrets to divulge. The mola team
recently returned from a successful tagging trip to Japan where
2 more tags were deployed on Mola mola with the help of the Kamogawa
SeaWorld and the Fisheries Cooperative Association of Kamogawa.
These tags are due to release on Halloween 2003. Whilst over in
Japan, the team also discovered a 1996 record of a Japanese Mola
mola that appears to be a new world record! Check out: http://news.nationalgeographic.com GENETICS Hundreds of tissue samples have been analyzed from mola populations spanning the globe. Some striking differences between certain populations are emerging. We may even have two new species of giant ocean sunfish. So stay tuned on the genetics front as well. COMMERCIAL IMPORTANCE and EDIBILITY While unpopular in Europe and the United States, molas are eaten throughout Asia. Taiwan and Japan are the largest markets. All parts of the mola are eaten including the skin, fin muscles, backbone, testes, and gut which is viewed as a delicacy. In Taiwan, the gut is served as "Dragon Intestines." Unlike their pufferfish relatives, e.g. Fugu, molas do not carry the deadly neurotoxin, tetratrodotoxin (Saito et al 1991). Mola mola is the most common bycatch of the drift net fishery, which targets broadbill swordfish of California and Oregon. According to reports from the National Marine Fisheries Society Southwest Region, between 1990-1998, 26.1% of the drift net catch consisted of the common mola, which translates to a catch of 26,503 individuals. 42.1% of the total discards were mola (Rand Rasmussen, pers comm). In the Spanish driftnet swordfish fishery on the Mediterranean side of the Gibraltar Straits, Mola mola constituted 71% of the entire catch in 1992, 93% in 1993 and 90% in 1994 (Silvani, L. et al, 1999). Until we establish baseline data on these fishes, we have no way of gauging how such capture rates are affecting the wild stock.
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Latest expedition news Japan 2006 Since 2001, the mola team has been tagging ocean sunfish Mola mola in Japan--strengthening our collaboration with colleagues from Kamogawa Sea World and the fishermen of the Fisheries Cooperative Association of Kamogawa. Out of all the mola tagging efforts worldwide, this partnership has undeniably proven the most fruitful. We have deployed 15 tags in total. (10 have reported, 3 have failed and two will release this September 06.) In April 2005, we were able to affix onto a mola dorsal fin the first ever real-time position reporting tag (called a SPOT tag-Smart Position Only Transmitting tag). We tracked its whereabouts (albeit quite sparingly) and while we only received a few location fixes, we demonstrated that a mola fin mount tag was a feasible endeavor with a bit more fine-tuning. This March 06 we put this idea to the test in Japan and are thrilled to report that we successfully deployed 2 real time SPLASH tags provided by John O'Sullivan of the Monterey Bay Aquarium. The beauty of these tags is that, like the old SPOT tags, they can report each time they clear the surface. Plus they report not only position but also temperature and depth. Both the SPLASH tagged molas were double tagged with Mk10 PATs (provided by Acadia Wildlife Preserve Inc.). The mk10 PATs archive temp, depth and location data based on light levels and, upon release from the fish, upload these stored data to satellite which are then relayed it to us. When the PATs release later this year, we will be able to compare the acquired SPLASH data with the archival data and see how well they match up. For more details on these tags visit www.wildlifecomputers.com. Chuck Farwell (Monterey Bay Aquarium) attached the tags with our mola geneticist Steve Karl (University of Hawaii, Manoa) and the extremely competent Kamogawa staff, particularly Toshiyuki Nakatsubo, while Tierney Thys (Sea Studios Foundation) and her 8.5 month old daughter, Marina, lent shore support and photo-documented the effort. The tagged fish were released on the same day, March 15th 2006, off Kamogawa with the help of the Fisheries Cooperative Association of Kamogawa. Water temps were 17.6 C, the seas were calm and the weather was lovely. We were quite lucky as the weather picked up the following day and squalls hammered the coastline. This was a momentous tagging expedition for multiple reasons. Not only did we deploy SPLASH tags on molas for the first time but we also had the good fortune of being able to partner with Dr. Dhugal Lindsay from JAMSTEC-the Japanese Agency for Marine-Earth Science and Technology. Dr. Lindsay conducts regular biological surveys along the Kuroshio current. For this expedition, we coordinated our two schedules so that he could sample in the same water masses as our tagged molas--at least for a short time. Using a state of the art visual plankton tow equipped with high definition video, he sampled not only the delicate critters living in these waters but also measured salinity, temperature and dissolved oxygen. Plus he used an Acoustic Doppler Current meter to get depth, temperature and salinity, and current speeds and directions for the upper 1200m. These data should provide tremendous insight into what is motivating the movements of these behemoth bony fish. Lastly, the wee Marina (Tierney's 8.5 month old daughter) accompanied the expedition so a new generation of potential ocean scientists has already received some valuable field experience. To see the mola and their whereabouts please click on
the link below: Japan Mola Tagging Team Members US members (past and present) Japan members (past and present) See also: NEW South
Africa January 2006 |
RESEARCH
FUNDING
AND SUPPORT PROVIDED
BY
National
Geographic
Committee
for
Research and Exploration
Taiwan
Fisheries
Research Institute
Smithsonian
Visiting
Research Fellowship
University
of South Florida,
Tampa
Pfleger
Institute of
Marine Science (PIER)
Women’s
International
Science Collaboration
(WISC)
Stephen Drogen
Arcadia Wildlife Preserve, Inc
email: info@oceansunfish.org
oceansunfish.org © 2002 - 2006 Tierney Thys, PhD. All rights Reserved
