Teetering on the edge of extinction

Basking shark

With a massive body and a mouth that emerges from the deep blue like a man-made dungeon cell, the basking shark resembles a great and terrible monster. But this is an animal whose terror resides only in its appearance. This harmless creature floats through the water with its mouth agape under a bulbous nose feeding mainly on plankton.

It is only its size and the industry of man that has brought the basking shark from an abundant population to the brink of extinction.

Twenty years ago kayakers and boaters in the Salish Sea would have had a chance to see a fairly common dorsal fin that did not belong to a whale. The basking shark, who is named for “sunning” itself on the surface of the water, is called “sunfish” or “sailfish” in some parts of the world. Basking sharks in this region are often referred to as the gentle giant slaughtered almost into oblivion.

“It’s absurd. They weren’t a threat,” said resident shark expert and author Gene Helfman.

The shark’s sharp decline started in the 1990s because high numbers were getting caught in fishing nets and the Canadian government authorized ramming to keep them from being a nuisance.

For shark lovers like Helfman, driving these marine animals into near extinction is a travesty. He is a Lopez resident and the author of “Sharks: The Animal Answer Guide.”

By the time Helfman was 13, he had read almost every book ever published about sharks. That passion still drives him today as he easily ticks off facts about the basking shark, an animal most islanders these days know little about.

This species is known to enter bays and estuaries as well as venturing offshore. Basking sharks are often seen traveling in pairs and in larger schools of up to a 100 or more.

Unlike the great white shark or hammerheads, basking sharks are known for being tolerant of nearby divers or boaters. Although there are reports of these sharks ramming boats while being harpooned.

These fish are further described by Helfman as large, innocuous and slow-moving like the shark version of the manatee.

In the British Isles basking sharks are an eco-tourism highlight and there is an extensive online database to alert visitors of potential sighting areas.

“A diver could get in the water with them,” said Helfman. “But you wouldn’t want to ride on them – they are sharp with scales.”

People have reported brushing up against a shark and receiving bad scrapes.

Recovery?

The basking shark is currently listed as vulnerable on the International Union for Conservation of Nature Red List. According to National Oceanic and Atmospheric Administration, basking sharks are listed as a species of concern dealing with the Eastern North Pacific population. Like many sharks, basking sharks are very slow to reproduce with up to a 14-month gestation period. According to Helfman, a lot of sharks take a year off to reproduce.

“So you’ve got an excess of two years in a animal that doesn’t mature until it is 20 years,” he said. “They were never super numerous so they were easy to wipe out and will be slow to come back.”

According to the Vancouver Sun, eight basking sharks were spotted in 2014 off the west coast of Vancouver Island but also as far north as Haida Gwai, an archipelago on the North Coast of British Columbia, Canada.

NOAA researchers reported five sightings in the Puget Sound area in between August and November of 2014.

In 2010 and 2011, NOAA Fisheries funded two projects studying the habitat and movements of basking sharks along the west coast. According to a NOAA press release, Southwest Fisheries Science Center has been examining historical records of basking shark sightings, coordinating with international partners on research and data collection, and deploying satellite tags on basking sharks. Three satellite tags have been deployed, one in 2010 and two in 2011. Tracking data from one of these tags show that basking sharks travel from the California coast offshore to waters close to Hawaii.

Basking sharks primarily eat plankton and are entirely passive feeders – there is no suction involved. Because plankton is so abundant the impact of the loss of this species in our waters is hard to measure. Plankton are tiny animals that can be found near the water’s surface.

“I would be very surprised if ever a major population consumed a significant portion of the plankton,” said Helfman. “Plankton is an incredible resource.”

And because there is a wealth of other marine animals that eat plankton – including whales, herring and baby fish – the plankton is not in danger of becoming too great in number.

What may be lost if the species never returns is further research on some of the mysteries of the animal. For instance: what do they do for the winter?

Research shows that basking sharks “disappeared” from the northern Atlantic in winter. It was speculated that they went into deep water and hibernated or mated. According to Helfman, more recently, with the help of satellite tags, researchers found they migrated south, as far as Brazil, but stayed as far down as 1,000 feet rather than feeding near the surface as they do in our waters.

“In all likelihood, they are following food such as zooplankton aggregations that are also in deeper water off Brazil,” said Helfman. “This isn’t surprising given that many marine animals that occur in shallow water at high latitudes tend to live deeper at lower latitudes.”

But many questions remain about these creatures.

Helfman recalled one story of a basking shark that was found at the mouth of the Amazon river. What was it doing there? We may never know. If the shark passes into extinction we definitely will not get those answers. For Helfman and other researches the inquires will never end.

“It’s a fascination I have never grown out of,” said Helfman.

Did you know?

• The basking shark is the second largest living fish, after the whale shark.

• Basking sharks have the largest liver: 2,200 pounds on land, seven pounds in water.

• They can grow to more than three feet in width, 5.2 tons and 30 feet long.

• They can travel as far as 3,000 feet under water.

• One female was found with about 80 pups with different DNA.

 

 

If you see a basking shark in West Coast waters, contact the basking shark sighting hotline at (858) 334-2884 or email basking.shark@noaa.gov.