We’ve been getting a number of calls reporting something flopping around in the water, appearing injured, possibly about to strand. The animals have been reported as entangled sea turtles, sharks, seals, and fish. Lately, what these fluttering creatures turn out to be is an “Ocean Sunfish.” Ocean sunfish , or Mola, are large, silvery, disc-shaped fish with long dorsal and anal fins, very tiny pectoral fins, an enormous head, and almost no tail. The “something flopping” frequently reported is the Mola’s tall, pointed dorsal fin waving above the water when the animal is in its normal, vertical swimming position. Sometimes on a sunny day you can see these fish lying horizontally at the surface, basking in the sun – hence the name “sunfish”.
There are three species of ocean sunfish, all in the Family Molidae. The round-tailed or common mola (Mola mola) is the species most frequently seen around Cape Cod. The other two species are the sharp-tailed mola (Masturus lanceolatus) and the slender mola (Ranzania laevis). All three species are found in temperate and tropical waters world-wide, usually in deeper water. They prefer water over 50 degrees Fahrenheit (10 degrees Celsius).
The common mola is very large, reaching on average 1.8 meters (5.9 feet) in length, 2.5 meters (8.2 feet) in height, and 1,000 kg (2,200 pounds) in weight. They hold the record for the world’s heaviest bony fish with one specimen that was 3.1 meters (10 feet) long and 2,235 kg (4,927 pounds) (Source: Carwardine 1995 via oceansunfish.org).
Sunfish primarily feed on jellyfish. Their diet also includes salp, squid, crustaceans, small fish, fish larvae, and even eel grass. They feed at all levels of the water column. Perhaps they have been sighted nearshore recently because they were following the food….
The New England Coastal Wildlife Alliance (NECWA) tracks local ocean sunfish sightings and also responds to stranded animals.
If you see an ocean sunfish, please complete this NECWA sightings form:
If you find a stranded ocean sunfish, live or dead, please:
call NECWA at 508-566-0009.