Scientists discover winter home of world's second-biggest fish (CNN)

[eppur_se_muova]

(CNN) -- The migration patterns of basking sharks have long mystified marine biologists, but new research has finally revealed where the world's second-biggest fish hide out for half of every year.

"While commonly sighted in surface waters during summer and autumn months, the disappearance of basking sharks during winter has been a great source of debate ever since an article in 1954 suggested that they hibernate on the ocean floor during this time," said Gregory Skomal of Massachusetts Marine Fisheries, one of the authors of a report recently published in "Current Biology".

"Some 50 years later, we have helped to solve the mystery while completely re-defining the known distribution of this species."

Using new satellite-tagging and a new geo-location technique, the researchers found that basking sharks make long migrations through tropical waters of the Atlantic Ocean during the winter, traveling at depths of 200 to 1,000 meters.

The researcher's data show that the sharks sometimes stay at those depths for weeks or even months at a time.



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more: http://www.cnn.com/2009/TECH/science/05/07/eco.baskingsharks/index.html





I'm sure all fishermen recognize the fish in that photo as The One That Got Away.

[Submariner]

1. Atlantic Salmon

is one of the last species that science did not know the fishes whereabouts during the winter. Once they found out it was the southweat corner of Greenland, that doomed the species to overfishing. Although, I would hope the basking shark is not on the "let's eat this one to near extinction too" list.

[Aragorn]

2. don't be so sore about that.

Note, in the photo upper left what appears to be bait on a hook. Where do they sell the fishing license for this? :)

[eppur_se_muova]

3. Basking sharks are plankton feeders, so can't be caught on a baited hook.

And apparently they aren't prone to forming large schools, so trawling would catch one only occasionally. This is largely why we knew so little about them previously.

[muriel_volestrangler]

6. Sadly, it is on the list from overfishing

Red List Category & Criteria: Vulnerable
...
The basking shark is extremely vulnerable to overfishing, as a result of its slow growth rate, lengthy maturation time, long gestation period, probably low fecundity, and probable small size of existing populations (Compagno 1984). The species has been the object of harpoon fisheries from small boats in many parts of its range. During the last century they were also harpooned by whaling vessels. The basking shark has also been taken in nets, including bottom gillnets and even bottom and pelagic trawls, and formerly was a problem to salmon gillnetters in the Pacific northwest of North America by fouling gillnets. The meat is used for human consumption fresh or dried salted; its fins are used for shark-fin soup; its liver, rich in oil and very large, is extracted for its high squalene content but the liver oil was formerly used for tanning leather for lamp oil; the hide is processed for leather and the carcass is rendered for fishmeal (Compagno 1984).

http://www.iucnredlist.org/details/4292

Over the years basking sharks have been hunted for a variety of reasons. Flesh for food, cartilage for assumed medicinal properties, liver-oil for burning and lubricants, and fins for the Asian shark fin soup trade, have and in some cases still are, the impetus behind basking shark fisheries. Although protected in some regions (as detailed above). fisheries still target the sharks, particularly as a lucrative form of by-catch. More international protection is needed whilst so little is known of the species numbers, biology, ecology and movements. Genetic analysis to determine any levels of population subdivision currently being carried out by an international group may help elucidate genetic isolation within international populations (eg. is the NE Atlantic European population distinct from the NW Atlantic / American population?)

Current Threats

Although in some areas protection has allowed a reduction in fishing pressure, the species is now suffering from its status as a tourist attraction. Direct harassment from a curious public is an increasing threat. Collisions with boats are not unusual and, although illegal in the UK, naive but deliberate disturbance is increasingly common. The image shows the damage that propellers can cause to basking sharks.

Basking sharks have also been known to suffer from intentional harm. The image shows a Basking shark which was found alive, stranded on the beach at Ferry side. Camarthenshire in 1995. It was suffering serious injuries to its snout and tail as well as multiple abrasions on its underside. The shark was put down by a local veterinarian who concluded that the shark had been deliberately gaffed (hooked by the head) and towed alongside a boat.

Another threat to sharks is static fishing gear. This shark was found just in time by divers off Achill Island, West of Ireland. Its snout had become entangled in lobster pot ropes during feeding with its mouth agape. Divers managed to release the shark from the ropes and set it free.

http://www.mcsuk.org/marineworld/baskingsharks/basking+shark+protection

[Ian David]

4. OMG!

[beam me up scottie]

5. You couldn't sleep the other night either, eh?

I can't get that stupid music out of my head after watching it.