Our team is
investigating the Molidae through two complementary approachespop-off
satellite archival tagging of individuals and genetic analysis
of global populations.
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/
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.
Well 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
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
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.
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."
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.