Squali "indigeni"

Photo PRETOMA

Un'interessante notizia proveniente da Mangrol (Gujarat) INDIA:
Gli squali balena che si vedono nelle acque al largo della costa del Gujarat potrebbero essere nativi dell'Oceano Indiano e non migranti provenienti dall' Australia, come comunemente ritenuto finora.
Gli squali balena sono spesso avvistati a Veraval e Sutrapada lungo la costa del Gujarat e al largo della costa australiana: alcuni studi avevano suggerito che gli animali in inverno migrassero in acque più calde alla ricerca di cibo, supportati dal fatto che i tempi della "scomparsa" in Australia e quelli della loro ricomparsa in India, coincidevano.
Questa teoria può essere ricusata se gli accertamenti preliminari del WTI (Wildlife Trust of India ) sono confermati: l'esame di cinque campioni genetici effettuati dall' organizzazione no-profit al largo del Gujarat non corrispondono con quelli provenienti dall' Australia.
Nemmeno i dati fotografici di identificazione degli squali balena hanno trovato una corrispondenza.
"I campioni raccolti fino ad ora non hanno trovato una corrispondenza in tutto il mondo, il che significa che sono unici", ha detto il Presidente del WTI.
Tuttavia, altri dati dovranno essere raccolti prima di poter categoricamente affermare che gli squali balena indiani sono un "popolo distinto".
Un consiglio scientifico è stato istituito per studiare gli squali balena.
È composto da rappresentanti dell'Istituto della fauna selvatica dell'India, Space Applications Centre, Istituto Nazionale di Oceanografia, WTI, Australian Institute of Marine Science, University of Illinois e altri. Oltre il monitoraggio dei loro movimenti, il Consiglio dovrà anche prendere in considerazione aspetti come le abitudini e vedere se vi sia stato un incrocio. Se i risultati sono dimostrati, ciò significherebbe una maggiore diversità genetica per lo squalo balena che migliorerà le sue prospettive di sopravvivenza.
L'Australia è considerata un rifugio sicuro per questo squalo e in alcune zone si sono registrati fino a 300-500 squali balena. Anche Veraval e Sutrapada sono considerate rifugi sicuri e ricchi di plancton; potrebbe essere quindi che la maggior parte degli squali balena indiani restino nelle acque del paese, mentre alcuni possano migrare.
Il WTI ha deciso di monitorare gli squali balena via satellite nei prossimi due mesi estendendo l'iniziativa agli stati del sud come il Kerala, dove gli squali balena sono stati avvistati.
Non più tardi di un decennio fa, gli squali balena sono stati cacciati a centinaia in Gujarat per l'olio di fegato e per la carne. Nel 2000-2001, oltre 500 squali balena sono stati uccisi lungo la costa . La caccia allo squalo balena è stata vietata in India il 28 maggio 2001; da allora, i cacciatori si sono trasformati in protettori.
Nel 2008 è stato firmato un memorandum d'intesa per un progetto di conservazione per creare consapevolezza ed intraprendere attività di ricerca per salvare le specie in pericolo. Il piano prevede inoltre una esplorazione delle opportunità di turismo della regione, legate allo squalo balena, cosa che garantirebbe ulteriormente la sopravvivenza della specie, fortemente minacciata.

Di seguito l'articolo originale, da Livemint.com :

Gujarat whale sharks may be native

Predominantly found off the Australian coast, they are believed to travel from there to warmer waters in winter in search of food
Maulik Pathak

Mangrol (Gujarat): The endangered whale sharks that are seen in the waters off the Gujarat coast may be native to the Indian Ocean and not migrants from Australia as is commonly held.
Billed as the world’s largest fish, the whale sharks are often spotted at Veraval and Sutrapada off the Gujarat coast. Some of them can grow as long as 45ft and weigh as much as three adult elephants.
Predominantly found off the Australian coast, they are believed to travel from there to warmer waters in winter in search of food. Based on the timing of this “disappearance” in Australia and their appearance in India, earlier studies suggested they migrate to Indian waters along with the ocean currents, said Arun Kaul, senior director, Wildlife Trust of India (WTI).
This theory may be challenged if initial WTI findings are confirmed.
The non-profit conservation organization said five genetic samples from whale sharks off Gujarat didn’t match with those from Australia. Photographic data from the Gujarat whale sharks also didn’t find a match, Kaul said.
“The samples collected so far have not found a match anywhere in the world, which means they are unique,” he said.
Still, more data will need to be collected before it can be categorically asserted that the whale sharks are a “distinct populace,” he said.
Aimed at studying the population and migration of whale sharks, the photo identification is being implemented in collaboration with Ecocean of Australia, which maintains a global whale shark database and is coordinating the research.
A scientific advisory council has been set up to study whale sharks. It includes representatives from the Wildlife Institute of India, Space Applications Centre, National Institute of Oceanography, WTI, Australian Institute of Marine Science, University of Illinois and others.
Besides tracking their movements, the council will also look into aspects such as breeding habits and see if there has been any cross-breeding.
If the findings are proven, it would mean greater genetic diversity for the whale shark, said S.K. Nanda, principal secretary, forests and environment, Gujarat. That would improve its prospects for survival.
Such a finding could also underscore the importance of the Save the Whale Shark Campaign that was launched in January 2004 as an initiative of the Gujarat forest department, WTI and the International Fund for Animal Welfare.
Funded by Tata Chemicals Ltd (TCL), it was launched to spread awareness and change perceptions about the endangered species, which is protected by law and on which very little scientific information is available in India.
“Perhaps we have discovered a population that could be endemic to Indian territorial waters,” said Satish Trivedi, senior official, community development, TCL. Such a discovery is significant for India, he said.
Currently, there are two established populations of whale sharks—the one residing off Australia and another in the Atlantic, Trivedi said.
Australia’s coast is considered a safe haven for the fish and some areas have recorded up to 300-500 whale sharks. Veraval and Sutrapada are also considered safe havens, besides which the sea bed there is rich in sea plankton and sea grass on which the fish feed.
It could be that most of India’s whale sharks remain in the country’s waters while some may migrate, said Manoj Matwal, researcher and assistant field officer, WTI, based on some of the observations made by the local fishing communities.
WTI has decided to track the whale sharks via satellite in the next two months using tags, something India has done previously for green turtles.
Although Kaul said the failure rate and lifespan of the tags would have to be factored in, WTI aims to extend the initiative to southern states such as Kerala where whale sharks have also been spotted.
As recently as a decade ago, whale sharks were hunted in their hundreds in Gujarat for liver oil to waterproof boats and for meat, which was exported. In 2000-2001, over 500 whale sharks were estimated to have been killed along the Gujarat coast. At $1,125-2,250 (Rs.51,525-101,250) apiece, they made for a lucrative catch.
It was wildlife film-maker Mike Pandey’s documentary Shores of Silence that publicized the whale shark’s plight. Before that, apart from the fishing community, few knew about them.
Whale shark hunting was banned in India on 28 May 2001, following its listing under schedule I of the Wildlife (Protection) Act, 1972.
Since then, the former hunters have turned into protectors. After the launch of the Save the Whale Shark Campaign, more than 240 of them, accidentally caught in fishing nets, have been freed by the fishermen.
Rajubhai Luvana, head of a fishing community in Veraval, said at least 25 whale sharks were freed from nets in 2010. The government provides compensation of as much as Rs.25,000 for the loss of nets. Over half a dozen fishing towns in Saurashtra have adopted the whale shark as a mascot.
In 2008, TCL and WTI signed a memorandum of understanding for a conservation project to create awareness and undertake research to save the endangered species. The plan also called for an exploration of whale shark tourism opportunities in the region.