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Mola research results

Preliminary Research Results

Preliminary analysis of the tags retrieved thus far suggests that Mola mola are moving from the waters off New England south along the continental shelf or shelf break. One fish traveled as far as the Gulf of Mexico, a distance of about 3,000km in 130 days. The tagged mola spent about 25% of their time in waters near the surface, though several individuals made frequent dives to as deep as 750 meters and spent extended periods of time at depth (>200 meters). The fish dove significantly deeper during the daytime hours than at night. In several of the tagged fish, we observed a change in their diving behavior over the course of the tagging period. In these cases, the mola went from spending most of their time on the surface with lots of diving to shallow depths (100-200 meters) in the autumn months; to little to no time spent at the surface and constant depths of 200-300 meters with occasional diving to as deep as 800 meters. This shift in behavior may be due to warming sea surface temperatures as the fish move southward, as well their encounter with the warm, rapid moving surface waters of the Gulf Stream. Data from the PSAT's with the most recent detachment dates (May 2007) suggest that as the fish are moving northward, they may resume shallower, surface oriented behavior.

See figures to the right and below for more information on mola PSAT tagging results!


Depth data of mola (tag ID 67321). Fish was tagged on 8/23/2006 off of Southern New England. The tag was attached for 5 months and resurfaced on 1/23/2007 off the coast of The Bahamas.

Map of 9 PSAT endpoints from tags attached to Mola mola in August/September 2006 off Southern New England. Tags were attached for up to 5 months

Most probable track of Mola mola tagged off Southern New England in October 2005. The tag resurfaced in January 2006 in the Gulf of Mexico. The fish traveled a distance of 3,000km in 130 days. Track reconstructed using methods of Francois Royer, UNH Large Pelagics Research Center.

Depth profile of mola (tag ID 67321) for three week long periods during the 143 day tagging period: a) 8/23/06-8/30/06, b) 9/22/06-9/29/06, c)12/21/06-12/28/06. Gray bars indicate night.