There is hope a study of close to 1,000 whale sharks found cruising the picturesque Ningaloo Reef in Western Australia may lead to further changing practices of marine vessels on shipping routes.

Key points: A five-year photographic sample of whale sharks finds around 16 per cent were injured in suspected collisions with marine vessels

A five-year photographic sample of whale sharks finds around 16 per cent were injured in suspected collisions with marine vessels The number of injuries doubled from 2011 to 2012–2013, with shipping routes becoming busier

The number of injuries doubled from 2011 to 2012–2013, with shipping routes becoming busier Experts say there is evidence to suggest that slowing down large ships in certain areas could prevent collisions and injuries

Surface wounds, amputations and deep lacerations were among the injuries seen on whale sharks photographed off the coast of Exmouth between 2008 and 2013.

The imagery was used in a new study that found one fifth of the gentle giants had scarring or amputations from suspected collisions with marine vessels.

Under WA legislation, the 15 tourism operators that host whale shark tours within the Ningaloo Marine Park are required to take images of each shark they encounter for photo identification purposes.

Those images make up a comprehensive database that helps to identify sharks that are returning to the area as part of their annual migration.

Whale shark scientist Emily Lester scoured images and videos taken by tourism operators and researchers and found about 16 per cent of the animals captured on camera showed some form of serious injury.

"Some of the major scars were probably bite marks from predators, but most were the marks of blunt trauma, lacerations or amputations arising from encounters with ships, particularly propellers," she said.

Alarmingly, Ms Lester and her colleagues from the Australian Institute of Marine Science also found that the injuries recorded during 2012 and 2013 had almost doubled compared with 2011.

She said one possible explanation was that there was an increase in shipping activity throughout the whale sharks' range, in and out of the Ningaloo area, and collisions were becoming more frequent.

Whale sharks, which spend much of their lives near the surface of the ocean, don't stand much chance against an iron ore carrier in WA and international waters. ( ABC News: Kathryn Diss )

Long-time issue

Previous studies have shown increasing global shipping traffic threatened marine megafauna — including whales, which come to the surface to breathe and therefore spend much of their lives in the surface waters of oceans.

Australian Institute of Marine Science principal researcher Mark Meekan, who has been studying whale sharks for more than two decades, collaborated with Ms Lester on the study and said the aim was to get a clearer understanding of the threat.

"It's a problem that's been going on for some time … this study was something that we tried to quantify with numbers," Dr Meekan said.

"These big animals rest on the surface of the ocean for an hour or so at a time and of course, at that time, while they're lolling about and gently swimming along at the surface, they're very susceptible to boat strikes.

"The problem here is that the whale sharks aren't necessarily staying at Ningaloo.

"These animals move off out into the Timor Sea and up to Indonesia quite frequently and the problem is, of course, that the scaring we're seeing and the increase in scaring through time may be happening in other places."

Whale shark injuries documented in a new study show 16 per cent of them have injuries. ( Supplied: Australian Institute of Marine Science )

Dr Meekan said because of the whale sharks' migration patterns, scientists did not know exactly where the collisions were occurring.

"We see some animals at the start of the season that are unmarked and by the end of the season have scars on them," he said.

"So there is some scarring happening in Ningaloo … But it may well be that the majority of this threat is actually happening in other places."

While whale sharks that survive strikes bear the scars, those that do not survive cannot be quantified because whale sharks are 'negatively buoyant', meaning that when they die they sink to the ocean floor.

Whale shark tourism delivers an estimated at $12.5 million in economic activity for the Ningaloo Reef region. ( Supplied: Leith Holtzman )

Global attention

At a global level, in 2017 the International Whaling Commission identified the need to create a strategic plan to reduce the threat of ship strikes, which it hoped would achieve a permanent reduction in ship strikes by 2020.

While Dr Meekan stopped short of saying he wanted to see shipping channels modified to protect the species, he said he hoped awareness would lead to monitoring and fewer collisions.

"It's clearly in places like the big shipping lanes that we might actually have to think about what's going on," he said.

"We do that for other big marine megafauna, like right whales for example.

"We have areas of shipping lanes where the ships slow down so much so that they don't actually hit whales.

"So the idea and the concept of looking out for marine megafauna and dealing with it through slowing the ships down could be easily applied to whale sharks."

According to a 2018 study, over half of the known mortalities in populations of North Atlantic right whales in recent decades had been from ship strike — endangering the survival of the species.

In 2013, changes were even made to shipping routes in the San Fransico Bay and Los Angeles area to specifically reduce the presence of ships where whales were known to frequent.

Department of Biodiversity, Conservation and Attractions research scientist and study co-author Holly Raudino said mitigating the impact of collisions was made harder because of jurisdictional capabilities.

Dr Raudino said the first step in reducing these interactions would be by "identifying hotspots of where these collisions are occurring through spatial modelling".

The report — Multi-year patterns in scarring, survival and residency of whale sharks in Ningaloo Marine Park, Western Australia — was published in the Marine Ecology Progress Series.

Major scarring from predator bites was also observed on 4.8 per cent of all whale sharks in the study.