According to a new study, one in five whale sharks has been injured by a commercial transport ship.
According to a new study, one in five whale sharks has been injured by a commercial shipping vessel, due to the world’s busiest shipping routes in the world.
- A new study in Australia tracked 913 whale sharks between 2008 and 2013
- The team found that about 20 percent showed significant scars or amputations.
- It is believed that these injuries come mainly from collisions with ships.
- Whale sharks swim near the surface, which makes them a frequent obstacle for boats.
A new study of whale sharks around the Ningaloo reef, on the western coast of Australia, found that one in five was injured in a collision with a commercial ship of some kind.
Researchers at the Australian Institute of Marine Sciences tracked a population of 913 whale sharks between 2008 and 2013 and found that about 20 percent showed new scars or signs of amputation of fins.
While the team believed that part of the scars came from predator bites, most were attributed to collisions with large marine vehicles.
Researchers in Australia tracked 913 whale sharks between 2008 and 2013 and found that about 20 percent should have signs of injuries consistent with colliding with a commercial ship, including injuries such as amputation or deep laceration.
“These large animals rest on the surface of the ocean for an hour or so at a time,” researcher Mark Meekan told Australia ABC News“And, of course, at that time, while moving and swimming gently on the surface, they are very susceptible to the blows of the boats.”
According to the researchers, it is difficult to identify where and when sharks are injured, as they travel across a wide region, to Indonesia, the Timor Sea and beyond.
“We see some animals at the beginning of the season that are not marked and at the end of the season they have scars,” Meekan said.
“So some scars are happening in Ningaloo … But it may be that most of this threat is happening elsewhere.”
To complete their study, the team relied on a database of photos and videos taken by 15 different whale shark tourism companies that operate around the Ningaloo reef.
Australian law requires that these companies document animals during their daily expeditions as part of the country’s preservation efforts.
The team found that the injury rate had grown faster over time, almost doubling between 2011 and 2013
The team used a database of videos and photographs collected by tour operators of whale sharks in Western Australia, which the law requires to help document animals.
The photos and video revealed a wide variety of injuries, including superficial wounds, fin amputations and deep lacerations.
Worriedly, they found that the injury rate seemed to be accelerating and had almost doubled between 2011 and 2013.
Researchers fear they may still be underestimating the frequency of injuries for several reasons.
“As a result, the ship would not feel a collision between a large ocean ship and a whale shark,” said researcher Emily Lester, “it is likely that we are underestimating the number of deaths due to the impact of the ship, since our study could only document sharks that survived their wounds’
The team believes that the main cause of the injuries comes from shipping ships, which are often so large that they probably wouldn’t even feel a collision with a whale shark
In addition, because whale sharks have negative buoyancy, they sink to the bottom of the ocean when they die, which makes it difficult to classify the absence of a particular whale shark due to death or simple migratory change.
Commercial shipping vehicles have been a threat to whale populations worldwide.
A study of North Atlantic free whales found that more than half of the deaths recorded were caused by commercial ships.
“It’s clear that in places like the big shipping routes we may have to think about what’s going on,” Meekan said.
Whale advocates have pressed to change commercial shipping routes to avoid the critical points of whales, but with the international waters involved along with companies from many different countries, it can be difficult to reach an agreement.
The team hopes that by using their data to show the critical points of injuries, it will be easier to negotiate on alternative routes.
What are whale sharks?
Whale sharks are the largest fish breed in the world.
A mature male shark can grow more than 32 feet, with the longest animal measuring 61 feet.
Despite their name, whale sharks are not whales, they are carpet sharks that move slowly and feed by filtration.
Sharks prefer warmer waters and migrate each spring to the west coast of Australia.
According to CSIRO research scientist Richard Pillan, whale sharks gather on the Ningaloo reef between March and October before migrating to other parts of the world.
Sharks feed on smaller fish, with their favorite food such as plankton, and surface during feeding.
They are more in danger of being hit and killed when they go through fishing boats and commercial vessels when they surface to feed.
Their number has decreased dramatically in the last 15 years, largely due to illegal fishing that is still practiced in parts of the world like Asia.
Very little is known about their mating behavior. The only litter size that has been documented had more than 300 puppies.
Source: National Geographic scientific researcher and CSIRO Richard Pillan