Saltwater crocodile ‘King Charles’ part of world-first research trial

A sprawling crocodile farm on the Tropic of Capricorn is not where you would expect a royal reception.

But wildlife researchers are greeted with just that when they come face-to-face with a 3.7-metre saltwater crocodile.

“Meet King Charles,” the farm’s owner John Lever says.

Charles is just one of the big male “salties” from Koorana Crocodile Farm taking part in a groundbreaking trial with scientists from the University of Queensland.

The world-first artificial insemination program is being conducted at the farm outside Rockhampton in central Queensland.

On any other day, you wouldn’t want to be this close to a crocodile like Charles.

But today, he’s lying in a cage on the back of a ute, as the research team go to work to collect semen.

Creating crocs

Semen collection and preservation is another step towards artificial insemination for crocodiles.

In the beginning, the small, on-farm trial produced one baby crocodile.

Lead researcher Stephen Johnston says he is confident a full trial would see a much higher success rate.

“They have some of the highest sperm concentration out of any species that we work with,” Mr Johnston said.

“We’re talking in order of anything around one-to-five billion sperm per millimetre.”

Koorana manager Adam Lever says commercially, artificial insemination made a lot of sense, and it would avoid the female animals being attacked by their mates.

Mr Johnston, an associate professor in wildlife reproduction, says it’s hoped the work will lead to more sustainable crocodile farming worldwide.

“When we first started, about eight years ago, we were trying to develop an artificial insemination program for crocodiles, [for us] to be able to learn how to collect the semen sample, to preserve it and then put it back into the female to produce fertilised eggs,” he says.

“We’ve probably collected semen from maybe 50 crocodiles now and we’ve got a base by which we can compare what’s normal and what’s not normal, so that’s important.

“We’re also extending on the original idea of artificial insemination by looking at how long the sperm will last in the refrigerator.

“That gives us an option if we were to collect semen from this farm and if we were going to another farm, we could essentially transport it and then do the AI at the other end.”

Despite funding issues, Mr Johnston and his fellow passionate researchers believe the work is beneficial for not only the conservation of crocodiles but other species around the world.

“This particular trip we’ve got some overseas researchers that are really interested in the crocodile as a model and understanding its reproductive physiology and how it compares to other vertebrates,” he says.

Mr Johnston says some of the samples collected will go to colleagues in Spain and Ireland.

“One of the things that the crocodile gives us is the chance to look at an animal that’s outside of the mammal range,” he says.

Breeding ground

The crocodile industry is worth millions of dollars in Australia.

It’s renowned for producing high-quality croc skins for the luxury fashion market, as well as meat and other by-products.

The commercially operated Koorana Crocodile Farm has more than 3,500 crocs in its watery stable and supplies meat and leather to Australian and overseas businesses.

Adam Lever says if successful, the AI technology could improve skin pattern quality through genetic selection.

“It was a world-first study when it first came through,” he says.

“It means we can take strong genetics from one male and inseminate our breeding colony with that one.”

Just like with beef breeding programs, researchers are optimistic.

“This is a farm and obviously there are commercial reasons for doing the sort of things similar to say cattle AI programs,” Mr Johnston says.

“In the United States with alligators, they have been quite successful at doing artificial insemination and that produces a number of offspring that way.

“Once we’ve established and we’ve got the technique working, I’m confident we’ll get it to work here.”

A potential game-changer

As saltwater crocodiles are a protected species, the industry operates under the scrutiny of government.

Mr Lever says AI would be a game-changer for the industry while ensuring the preservation of the species and contributing to the economy.

“If we had a selection of five good-sized males then we could hopefully inseminate 50, 60, 70 females.

“We envisioned from the start that it would be beneficial for conservation studies for other species and that’s the main aim for this.

“But if it can be utilised in the farming industry we’ll definitely jump on board with it.”