Gone Fishin' : Basking shark Is One Of Largest Seen In Our Waters

June 11, 2009

Release from: Nelson Sigelman
Martha's Vineyard Times

Greg Skomal, Massachusetts Division of Marine Fisheries (DMF) biologist and shark expert, has traveled to a variety of exotic and strange locations to study sharks. Those destinations have included the Great Barrier Reef off Australia and the Red Sea in the Middle East. On Sunday he only needed to go to Gay Head.

Saturday afternoon Aquinnah police called Greg to tell him that a large shark had washed up on the beach. He grabbed a kitchen knife because his dissection kit was at his New Bedford laboratory and went to take a look at the fish, accompanied by his two-year-old son, Wilson, and wife, Kimberly.

Greg likely thought of the line in that famous fish movie when the Amity police chief sees the shark and says they will need a bigger boat, only Greg was going to need a bigger and sharper knife.

The basking shark was 30 feet long and likely weighed about 5,000 pounds said Greg. When he arrived it was rolling in the surf washing up on Moshup Beach within sight of the Gay Head Cliffs.

Greg said that for a brief moment he thought of donning his waders in order to get closer to the shark. Then he considered what might happen if the fish rolled the wrong way - sushi for Greg.

On Sunday he arrived better prepared to examine the fish. A team of volunteer assistants - including Jeff Kneebone, a doctoral student from Univ. of Mass Dartmouth, Louis Hall, a MV Charter School teacher, and Justen Walker, educational coordinator and camp director for Felix Neck - accompanied Greg and lent a hand in the arduous task of dissecting the fish.

I asked Greg if the basking shark washed up with one of my fishing plugs in its mouth. "The day one of those fish takes a lure is the day sportfishing changes," Greg said.

Sunday was a beautiful day. Greg and his team first measured the fish, and then began a dissection that included taking samples of the liver, reproductive organs, and backbone.

Cutting into a basking shark is not easy. The scales are basically teeth and very abrasive. "It was the biggest one I've ever cut," said Greg. "I shredded my hands just leaning on it."

The shark was a male and appeared to be in perfect health and pristine shape. The claspers, the sharks sex organs, were three feet long. "It was an amazing fish," he said.

Greg said he has looked at dozens of fish that have come ashore over the last 20 years including one that washed up on Dogfish Bar in 1989.

Greg said in almost all the cases the fish were in good shape. He has no definitive answer as to why the sharks washed up but he suspects it has to do with a miscalculation on the part of the sharks.

Basking sharks are very large fish that must swim about two to three knots in order to keep enough water moving over their gills to breathe. He thinks the fish sometimes are unable to sustain forward movement when they get caught up in shallow water or areas of high surf near rocks.

The Vineyard experienced a full moon tide and high surf on Saturday. Greg said there are reports that the shark was initially seen alive and struggling in the surf. "All it has to do is get inside the surf line," Greg said. "It doesn't take much to kill these fish."

The first weeks in June are prime time to see basking sharks in Island waters. The basking shark has a huge mouth and tiny teeth. The shark uses comb-like gillrakers to filter small shrimp-like creatures from the huge volume of water it takes in when it opens its mouth.

The appearance of a basking shark on the beach follows the release of a study that shed new light on the migratory routes of basking sharks.

Greg, the lead author of a study, "Transequatorial migrations by basking sharks in the western Atlantic ocean," published in the June 23 issue of Current Biology and his fellow biologists unlocked one of the mysteries associated with basking sharks, the world's second largest fish.

The study identifies the shark's previously unknown winter habitat. The discovery has implications for conserving the species, according to state environmental officials.

For years scientists believed the shark moved to deeper water and hibernated.

However, with the help of satellite technology, the study revealed that Atlantic basking sharks, previously believed to inhabit only the waters off the United States and Canada, have a range that stretches the length of the Atlantic Ocean.

The basking shark has little food value, but was once fished heavily in the early part of the 20th century in the waters surrounding Great Britain, primarily for the oil found in its huge liver.

It is now listed as a vulnerable species. Estimates place the global population at 10,000 individuals.