Research

Expeditions

Galapagos 2011

San Diego 2010

Bali 2008

San Diego 2006

Japan 2006

South Africa 2006

Japan 2005

Indonesia 2004

South Africa 2004

Taiwan 2000

Our team is investigating the Molidae through two complementary approaches–pop-off satellite archival tagging of individuals and genetic analysis of global populations.

Select a topic below to read more...

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
/news/2003/05/0513_030513_sunfish.html
.
The mola team is also planning to tag more sunfish this July and August off the coast of California. And come December, theyll be heading to South Africa.

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."

Video Fish Scientist Humor - YouTube

Unlike their pufferfish relatives, e.g. Fugu, molas do not carry the deadly neurotoxin, tetratrodotoxin (Saito et al 1991).

BYCATCH
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.

 Japan 2005

This marks the fourth year, the mola tag team has visited Kamogawa SeaWorld in Japan. Our first trip in 2001 included Heidi Dewar, Ellen Freund, Chuck Farwell from the Monterey Bay Aquarium and Tierney Thys. The last 3 trips (‘03,’04, ‘05) the team has whittled down to just Farwell and Thys.

dinner

Celebration dinner with the wonderful staff from Kamogawa SeaWorld.

team

Chuck Farwell, Tierney Thys and Nakatsubosan


Expedition News—Japan Mola Tagging April 2005

Plan B saves the day

While it may have been perfect timing for enjoying the serene profusion of cherry blossoms in Japan, it was suboptimal timing for capturing wild molas off the east coast.Nevertheless, our journey ended in success—thanks to the advance preparation of our consistently reliable friends at Kamogawa SeaWorld. Fortunately, back in March, the Kamogawa staff had collected 3 molas, as a Plan B, just in case the seas didn’t deliver during our April visit. Turns out they were right to plan ahead as the seas held tightly to their molas this trip.

Every year has presented different tagging challenges as well as a fair share of good luck. In the first year, 2001, we deployed 3 tags in April and all of them reported. Fortunately, one tag was retrieved by fishermen in the northern Aomori prefecture, sent to Kamogawa SeaWorld, and returned back to us wherein we extracted a complete and tremendously exciting data set. (Note: Retrieved tags offer up an uncompressed dataset while tags that release from the animal in the wild transmit their data only in compressed form.) In 2003, we deployed 2 more tags that both reported additional data and in 2004 one of our 3 deployed tags offered another dataset. At present, we are putting the finishing touches on our manuscript reporting the data from these tags.


In order to transmit, the SPOT must clear the water. This means that only those marine animals exhibiting consistent surface bouts are viable tag- toting candidates. Such critters include marine mammals and turtles who must come to the surface to breathe; some species of shark that regularly slice the surface with their dorsal fins and several species of fish like striped marlin that stick part of their tail fins clear of the surface. We figure the ocean sunfish, with its characteristic surface basking behavior and habitat of flapping its dorsal fin out of the water, particularly in the high latitudes, is a prime candidate for SPOT toting.
SPOT tags have been successfully deployed on a number of fish species including salmon sharks, blue sharks, mako sharks and most recently striped marlin. Visit the near real-time tracks from the Tagging of Pacific Pelagics Project, part of the Census of Marine Life www.coml.org. http://las.pfeg.noaa.gov/TOPP/TOPP_tracks.html website to see the exciting and fun tracks of these animals (For more information on SPOT tags, see www.wildlifecomputer.com.)

anchovies

anchovy catch

Harvesting the set nets full of anchovies

mola tagging

Affixing the SPOT to the mola

livewell

Transporting the mola from the holding tanks at Kamogawa to the fishing boats

mola release

Releasing the mola to ply the waters and collect data.

black kites

The magnificent fish hawks (black kites Milvus migrans) that welcomed us back at the docks with open talons.

black kite

 

 

 

This year (2005) in addition to deploying 2 more PAT tags, we decided to try something new—a real-time tag--called a Satellite Position Only Tag (SPOT). For details see sidebar.

As in past trips, our plan was to work with the fishermen of the Kamogawa Fisheries Association to capture, tag and release wild molas from set nets. Starting at 4:30 AM, we met with the head of the fisheries operation, Mr. Sakamoto--a strapping 38 year old--who’s been running this tight operation for upwards of 20 years. He and the head of the fish market, Mr. Watanabe, welcomed us with big smiles, black coffee and seaweed tea—like drinking a shot of hot ocean. These fishermen and the Kamogawa SeaWorld staff have become like family to us over these past years of working in Japan.

Sakamotosan and Watanabesan shared with us the daily printout of the Kuroshio Current location and temperature readings of the greater Kamogawa coastal area. Turns out the water temperatures had been unseasonably low for the past few days (13¾C) but were turning warmer since our arrival (17¾C). After finishing our tea, we were off to the boats in a flash.

Our first day out, the fishermen discovered the main set net—the one most likely to have molas--had torn substantially due to the previous day’s fast currents, rendering the net out of commission for at least 3 days. This left two set nets to sample. We headed to the near shore net.

Watching the harvest of these nets is quite an experience. Maneuvering a complex maze of yellow buoys outlining the net boundaries, the fishermen position 2 boats one across from each other to begin their haul. As they lift the net section holding all the fish, the water starts a slow dark boil. Hidden schools below press tightly together and a confetti of glitter rises up from the depths—silent sequins scraped from the skins of the panicked silvered swimmers below. With each tug of the net, tail fins and fin flicks smash and slice the surface frothing the water into silver white. A smaller net is lowered in to scoop up the living silver bounty and purse load after bulging purse load are pulled from the depths. Nothing escapes.

Day after day, the nets offered up large schools of anchovies and, on one day, a tremendously rare school of more than 400 good-sized yellowtail jacks, but no molas were to be found. With time running out, we had to embrace plan B and accept Kamogawa SeaWorld’s generous offer to use the molas they’d captured back in March. With the staff’s expert assistance, we placed one SPOT tag on the dorsal fin of their largest mola in the holding tank at the aquarium. The great benefit of doing this bit of new tagging on shore was that we could observe the tagged animal for two days and record its acclimatization to the tag process. It responded wonderfully well to its additional fin load. In fact, within just a few minutes of tagging, it slurped down a tasty mixture of squid, oysters, shrimp and tuna paste. For the remainder of our watch, the SPOT tagged mola expressed normal swimming behavior and the tag transmitted successfully each time the fish’s dorsal fin cleared the water’s surface in the holding tank.

With one day remaining, we transferred the SPOT tagged mola, along with another mola, to two transport tanks, trucked them to the fishing docks and transferred them both into a large live well on board the fishing ship.

Then it was off to the release point offshore--as far as the fishermen were willing to motor us away from their set nets. Right before the release, we attached the two remaining PAT tags, took genetic samples, measured total length and bid our little autonomous mola vehicles bon voyage and sayonara.

Fingers crossed the SPOT tag delivers!

Random facts: Mola meat is selling for 500 yen/kg this year while last year, with more animals around, it sold for 350 yen/kg.

seal

An adorable spotted seal (Phoca largha) that showed up on the beach the day we arrived.

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