Methea Sapp-Cassanego, August 4, 2007

NOAA Teacher at Sea
Methea Sapp-Cassanego
Onboard NOAA Ship Delaware II
July 19 – August 8, 2007

Mission: Marine Mammal Survey
Geographical Area: New England
Date: August 4, 2007

Weather Data from Bridge 
Visibility: 5 in haze lowering 3 to 5 in showers
Wind Direction: Southwest
Wind Speed: 10-15 knt increasing to 20 knt.
Swell height: 3-5 feet building 4-6 feet

A solitary ocean sunfish basks in the sun while a shearwater skims by.
A solitary ocean sunfish basks in the sun while a shearwater skims by.

Science and Technology Log 

Rotations have been going like clock-work, although today’s sightings have again been numerous we still have not found any more right whales.  Again I’ll fill today’s blog with some species profiles of animals we’ve seen today.  By the way, the sightings list for today includes, pilot whales, minke whales, offshore bottlenose dolphins, common dolphins, white-sided dolphins, beaked dolphins and harbor porpoise.  We’ve also seen a few Mola mola which are not tallied since they are not marine mammals.

Atlantic White-sided Dolphin (Lagenorhynchus acutus) Researchers and scientists also refer to this animal as a “Lag.” Identification: At first glance the Atlantic white-sided dolphin looks very much like the common Atlantic dolphin. Its body is slightly more robust then that of the common Atlantic dolphin; its tail stock is also thicker.  The upper portions of the body are black while the lower belly and chin are white; a long horizontal grey strip bisects the upper and lower body portions. The flippers are also grey.  Max length and weight: 510 pounds and 9 feet. Diet and Feeding: Fish and squid Migration: No organized or seasonal migration Distribution: Found in cold waters of the northern North Atlantic from the Northeast United States to Northern Europe and Southern Greenland.    Special Note: Atlantic White-sided Dolphins are especially gregarious and are often seen swimming along the side of boats and bow riding.  They will also mingle and feed with fin and humpback whales. Several hundred are caught and killed each year as a source of food by the Faroese Island people.  

References 

Collins Wild Guide: Whales and Dolphins. HarperCollins Publishers, New York, New York. 2006.

Ocean Sunfish (Mola mola)

Identification: This oddly shaped fish is most easily identified when it is basking at the surface. Its large disk-like body is pale grey to white in color; lacks a true tail; both the dorsal fin and anal fin are extremely elongated so that the fish is as tall as it is long. Sunfish are solitary but may occasionally be found in pairs.

Max length and weight: Averages 5 feet 9 inches in length and 2,200 pounds.  Records exist of sunfish spanning 10.8 feet in length and weighting just over 5,000 pounds.

Diet and Feeding: Primarily seajellys but also feeds on salps, squid, crustaceans, comb jellies and zooplankton. Sunfish are pelagic and may feed at depths just shy of 2,000 feet.

Migration: No organized or seasonal migration

Distribution: Ocean sunfish are found globally in both temperate and tropical waters. Research suggests that populations of sunfish inhabiting the Atlantic and Pacific have greater genetic differences than populations in the Northern and Southern Hemispheres.

Special Note: The ocean sunfish poses no threat to humans and is commonly approached by divers. Its meat is of minimal economic importance although there seems to be an increasing popularity in sunfish cuisine and it is considered a delicacy in some parts of the world. The sunfish has few natural predators due to the thickness of its skin which can measure up to 3 inches in some places.  More often than not the sunfish encounters its greatest threat when caught in fishing gear.  Sunfish by-catch totals ~30% of the total swordfish catch off the coast of California and ~90% of the total swordfish catch in the Mediterranean.

Impressive size and startling appearance make the ocean sunfish a favorite attraction at the Monterey Bay Aquarium.  This photo is freely licensed via Wikimedia Commons and is courtesy of Fred Hsu.
Impressive size and startling appearance make the ocean sunfish a favorite attraction at the Monterey Bay Aquarium. This photo is freely licensed via Wikimedia Commons and is courtesy of Fred Hsu.

 

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