The Maugean skate is a small- to medium-sized species, probably surviving only in Macquarie Harbour. A captive management program that is conducting close population monitoring on this species has raised an additional 124 individuals. This program began almost two years ago with just four skates captured from their natural habitat, which is home to industrialized salmon farming. Scientists are currently searching for ways to breed these endangered skates in captivity. For now their aim is to return the skates to the wild, but that’s only the beginning of these unsuspecting creatures’ stories.
Right from the start of the program, their team has faced a number of obstacles. They eventually lost two first skates–one to a bacterial infection and the other to failure to thrive as an underweight. Despite these setbacks, the program boasts a significant achievement: 96 Maugean skate eggs have hatched and survived in captivity, alongside an additional 26 skates that hatched from wild-sourced eggs.
Captive Management Program
The captive management program operates on a decade-long cycle. It has multiple facilities, with two based at the Institute for Marine and Antarctic Studies (IMAS) in Taroona. Skates are separated into tanks based on age group for their continued care and development, as well as health monitoring and research purposes. Our biggest female Maugean skate, nearly two years old, is already maturing eggs, showing steps toward going into production for breeding efforts.
One of the pillars behind the Junction program’s success is constant vigilance and scientific methodology. Staff often ‘candle’ the skate eggs to check on the development of the embryos. This more conservative approach wants to increase the odds of survival for these fascinating endangered reptiles.
“As soon as you have animals in captivity, there are things that will happen that you just can’t predict.” – Professor Jayson Semmens
The program is based on proven practices already employed by zoos and aquariums. Professor Semmens stated, “We will do a studbook — the exact same method as zoos and commercial aquariums — to determine who should breed with who.” This very detailed process is intended to ensure that they best capture the genetic diversity of the wild population.
Mating Behavior Observed
Over the last year or so, the two adult Maugean skates in captivity started courting each other, a signal they might breed, which bodes well for future efforts. Upon closer observation, researchers noticed bite marks on the female’s wing, indicating aggressive mating interaction. Genetic testing has shown that this female skate originated from an egg found in the wild. She is a member of one of 15 different “families” of skates living in Macquarie Harbour.
The maturation process differs between the sexes. Males typically reach maturity in four years, females sometimes at five years of age in the wild. However, with better practices in captivity this timeline could be moved up significantly.
“In captivity, they might not be behaving as they do in the wild … it definitely looks like they’re going through the mating process,” – Professor Jayson Semmens
At least one of their fly-studying counterparts is still baffled by how similar these conditions are to the wild.
Future Release Plans
Looking forward, scientists are discussing potential release strategies for the Maugean skate. Part of the plan involves returning some people to their natural environment. We will learn how they evolve and thrive under extreme environments, even if in contained settings.
As Professor Semmens pointed out, that raises a lot of considerations that need to be unpacked before any such release. “Do you need to, for instance, have the embryos and the eggs raised at lower oxygen levels to make sure they can cope with it, or can they cope with it no problems?” This question conveys the challenges with reintroducing captive bred skates back into an environment where the conditions are very different.
“There could be other ways of doing it, such as collecting eggs from the wild to raise and release,” Professor Semmens noted.
“The plan is to release them first, and basically help us understand the process,” – Professor Jayson Semmens
As efforts continue to understand this unique species better, the research community remains vigilant about both the successes and challenges posed by breeding and reintroducing Maugean skates.
