Seasonal, Thermal, and Zonal Distribution of 



Ocean Sunfish, Mola mola (Linnaeus), 



off the North Carolina Coast 



David S. Lee 



North Carolina State Museum of Natural History, 

 P.O. Box 27647, Raleigh, North Carolina 27611 



ABSTRACT. — Most previous information on the ocean sunfish, 

 Mola mola, has been derived from beached specimens and contributed 

 little to our understanding of typical distributional patterns of the spe- 

 cies. More than 60 encounters with Mola mola in North Carolina's 

 offshore waters reveal that this fish is an epipelagic migrant, occurring 

 in shallow water (10 to 40 fathoms in depth) commonly in the spring 

 between mid-March and mid-June. In the fall it has been seen less 

 frequently (mid-October through November), and the species is essen- 

 tially absent in the winter. 



In spite of its cosmopolitan distribution, little information is avail- 

 able concerning the natural history of the ocean sunfish, Mola mola 

 (Linnaeus). This is particularly true in the southeastern United States, 

 where nearly all records are of animals found awash in the surf. Because 

 such records may reflect atypical patterns of movement and distribu- 

 tion, observations on the .seasonal, thermal, and zonal distribution of 

 Mola at sea are of interest. Between 1977 and 1986, I conducted 126 

 offshore trips for trye primary purpose of monitoring seasonal occur- 

 rence and abundance of marine birds and mammals. During this period, 

 however, I also incidentally observed other pelagic organisms (see Lee 

 and Booth 1979, Lee and Palmer 1981). 



All but seven of the offshore survey trips departed from either 

 Oregon Inlet or Hatteras Inlet, Dare County. Of the seven trips that did 

 not, five were from Beaufort Inlet, Carteret County; one was from Wil- 

 mington, New Hanover County; and one was from Virginia Beach, Vir- 

 ginia. Each daylong outing lasted 10 to 1 1 hours and typically followed 

 predesignated transects of 20 to 55 miles (32 to 88 km) from the point of 

 departure and into the Gulf Stream. All of the Oregon Inlet and Hatter- 

 as Inlet surveys extended to at least the 100-fathom contour, and many 

 went several miles beyond the 1,000-fathom contour. Trips were made 

 at all seasons, but monthly coverage was uneven (see Table 1). Ideally, 

 water surface temperature, directional movement, and time and location 

 of sightings were recorded for each sunfish observed. Data are not uni- 

 form, however, because some charter boats lacked LORAN and other 

 recording equipment, sea conditions necessitated abbreviated record 



Brimleyana No. 12:75-83, September 1986 75 



