Science & Technology

Shark swims 4,000 km, returns to Galapagos but whereabouts now are unknown

By Susana Madera

Quito, Jul 12 (EFE).- A veil of mystery at present obscures the status of Cassiopeia, a female scalloped hammerhead shark who made a round trip journey of 4,000 kilometers (about 2,500 miles) from Ecuador’s Galapagos archipelago to Central America but whose whereabouts now are unknown.

The pregnant female shark last February was located by satellite transmitter in the Galapagos Marine Preserve and then some weeks later arrived on the coast of the Gulf of Panama, a well-known area for her species to give birth.

During her swimming journey of a little more than two months, Cassiopeia – who belongs to a species that is in critical danger of going extinct – was initially followed by satellite between the Galapagos and the birthing zones along the Pacific coast of Central America.

Scientists like Pelayo Salinas de Leon, with the Charles Darwin Foundation, presume that Cassiopeia left for the Central American coast seeking a “nursery” area for her offspring since along the continent’s coastline there are a large number of mangrove swamps where her baby sharks can find food and protection during their first few years of life.

Although in the Galapagos there are sites that are favorable for giving birth, experts assume that Cassiopeia set out for Central America because along the continental coastline there are many more potential “nursery zones” and her arrival off the coast of Panama, between March and April, coincides with the period during which baby hammerhead sharks begin to appear in the shallower areas near shore.

Sphyrna lewini, the species to which Cassiopeia belongs, has a gestation period of about 11 months and gives birth to between 12 and 41 babies per delivery. The mother departs after giving birth and the baby sharks must fend for themselves, and thus the mangrove-covered areas and other coastal environments provide them with perfect zones to feed, shelter and grow.

After her “express round-trip journey” from the Galapagos, the female shark returned to the archipelago leaving a store of basic information which experts are using to move forward with analyzing the behavior of these animals to better learn how to preserve the species.

“They are a species that knows no boundaries or obstacles. This animal crossed the exclusive economic areas of at least three countries – Ecuador, Costa Rica and Colombia” before arriving at the coast, said Salinas, noting that the sharks also migrate through areas where they have no protection.

Cassiopeia – who measures more than 2.5 meters (8.2 feet) long and is between 10 and 25 years old – has been a key individual for experts because “she had proven with real data the hypothesis that a portion of the females leave the Galapagos and go to the continent” to give birth in the nursery zones.

The scalloped hammerhead shark – Salinas de Leon said – is a species that is in “critical danger of extinction” and “unless we act in a joint manner” to protect their migration routes by establishing biological corridors and implementing a regional fishing management plan, the populations “sadly are going to continue to deline.” Thus, the information gathered thanks to this shark’s “express trip” is very valuable.

“Cassiopeia is a revelation and emphasizes the need to work jointly because she demonstrates the internationality of this species,” Salinas de Leon said, adding that national and international fishing fleets operate in the area to “directly and indirectly” capture sharks.

Overfishing and unregulated fishing are the biggest threats to the hammerhead shark, but also climate change and habitat destruction are harming the species, he said, noting that over the past 50 years or so “between 30 and 50 percent of the worldwide mangrove swamps have been lost.”

In general, sharks are apex predators in the food chains, operating like the “doctors of the oceans” to ensure that “everything remains in balance” within the ecosystems, where they are specialists in feeding on sick or old individuals of other species and thus their disappearance would result in a huge imbalance.

Holding a doctorate in Marine Biology, and having conducted studies in New Zealand, the United Kingdom and Spain, Salinas de Leon lamented the fact that contact was lost with Cassiopeia when she returned to the Galapagos, but he expressed hope that this situation was due merely to the tracking device becoming detached from her due to natural causes and that she had not been caught by one of the fishing boats.

In other cases, he said, experts have known that an animal had been caught by fishermen “because the (animal’s tracking signature) mysteriously appears in somebody’s house.”

“I’d like to think that Cassiopeia is still swimming, free and happy,” he said, noting that the last signal received from her came about two months ago.


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