Distribution, migration and behavior of the ocean sunfish, Mola mola, in the north Atlantic 
PI: Hunt Howell and Inga F. Potter
PROJECT DESCRIPTION:
The purpose of the project is to improve the understanding of the habitat, migration routes, behavior and environmental
associations of M. mola in the North Atlantic Ocean. The project is the first to examine the distribution, movement,
and behavior of Mola mola in the North Atlantic, establishing a baseline of information for the species in the region.
The primary objectives of the study are: 1) to determine the spatial and temporal distribution of Mola mola off the
northeast coast of the United States; 2) to study their movement and migratory patterns; and 3) to quantify their
temperature and depth preferences. Results of the project will contribute to the development of predictive models and
management strategies that will aid in the management of a poorly understood marine species, whose populations are
believed to be declining due to bycatch and its increasing commercial use in Asia. Data on distribution of Mola mola may serve as a useful indicator of nutrient rich areas with high productivity, where other important marine organisms
may be found.
PROGRESS thru 10/31/2006:
The project has made good progress in its first six months, and is in keeping with its original objectives.
Objective 1: To determine the spatial and temporal distribution of Mola mola off the northeast coast of the
United States (by analysis of aerial sightings of M. mola in from the North Atlantic Right Whale Consortium and the
OBIS-SEAMAP Databases).
There has been continued collection and analysis of aerial survey data from past years as well as from the current year
(NMFS Right Whale Sightings for the northeast US , spring-summer 2006).
Objectives 2 & 3: To study the movement and migratory patterns of M. mola , and to
quantify temperature and depth preferences (by tagging individuals with pop-up satellite archival tags (PSAT's)).
Fourteen fish were tagged with PSAT's during August and September 2006. Twelve of the tags were deployed from a fishing vessel
off Nantucket Island , MA and two tags were deployed from a fishing vessel out of York , ME. Following the protocol outlined in
the project proposal, tagging was successful in all cases. Thus far, one tag has popped off prematurely due to the fish staying
at a constant pressure of less than 20 meters for several days. The tags are programmed to pop off between five and eight months,
and as such, they are projected to pop-off between mid-January and late May 2007.
PRELIMINARY DATA
With 13 tags currently deployed, 1 tag un-deployed and 1 tag prematurely detached, the large majority of the PSAT data has yet to be
retrieved. The tag that popped-off prematurely (ID 67331) did so on 9/14/06 and was attached to the fish for a period of 14 days.
The tag popped off due to “constant pressure” because the fish stayed within a depth range of 0-20 meters for 4 consecutive days.
Based on the pressure data, the fish appeared to be alive and active up until the pop-off date. The pop-off location was
approximately 440 km from the deployment location, along the southern shore of New Jersey . During the 14 day tagging period, the
fish maintained a much shallower depth range than fish tagged during the previous field season (0-70 meters) and stayed mostly
within a temperature range of 18-20°C (68%).
Analyses of NMFS aerial survey data, and local reports of Mola from fisherman and beachgoers on Nantucket Island , were combined to provide information on the local seasonal distribution of M. mola from May – September 2006. Based on the aerial survey data, Mola sightings were first reported on June 7, 2006 in the Great South Channel and peaked between late July – early September with large numbers of fish reported in both the northern Gulf of Maine and the Great South Channel (there were no NMFS aerial survey reports in August 2006). On Nantucket , Mola sightings peaked mid-September with large numbers of Mola reported in shallow, inshore waters (100-200 meters from shore) for a period of several weeks. NMFS aerial surveys were not conducted in August 2006, and were then only conducted sporadically in September and October. Recent surveys report little to no Mola sightings for the Gulf of Maine , Georges Bank, and the region to the south of the Cape and Islands .
PLANS FOR THE NEXT SIX MONTHS TO YEAR:
In the next six months, analysis of PSAT data will continue as data becomes available. Aerial survey analysis will also continue.
The 1 remaining PSAT may be deployed off the coast of Florida in the winter months (January –February 2007).
CONFERENCES
Inga Potter presented preliminary data in a poster at the Large Pelagics Symposium, Gulf and Caribbean Fisheries Institute
Conference in Belize City, Belize. Nov 6-12, 2006.
