This thing called life

This thing called life

Murray crays: unicorns of the river

My Honours student Verita with a Murray Cray in the Ovens River. Susan Lawler

Murray crayfish never fail to impress. When you pull up the hoop nets from the murky depths and those large white claws start waving about, the uninitiated invariably recoil, sometimes even threatening to upset the boat in their efforts to avoid these spiny armoured angry aliens.

Probably this is why fishers enjoy catching them so much. The pay- off is a sense of being part of something strange and magical. There is a thrill involved in grabbing one of these beasts while the claws wave and snap and the tail flips water in your face. There is the joy of discovery and secret knowledge when you turn it over to check for the berries that mean it is a fertile female.

If you have not seen a Murray cray live, feel free to have a look at me and my ten-legged friends as shown on Catalyst last year.

In the past, a long weekend could be self-catered by the catch, a pot of lovely lobster meat after a day on the river. Nowadays, fishers are struggling to fill the modest bag limit of 5 per day. Legal sized individuals are increasingly hard to find, and the really large animals that could feed a family and provide bragging rights for the rest of the season are just not seen anymore.

Murray crays used to be abundant enough to support a commercial fishery. Now they are protected in South Australia, where they are as rare as a mythical beast. They are protected in the ACT, where they can be found but are listed as vulnerable. They can no longer be found near Mildura, where they used to support a recreational fishery. And they are threatened in Victoria and part of an endangered lower Murray ecological community in NSW, but are still part of a recreational fishery in those states.

Naturally, there are restrictions. Murray cray season is closed from the beginning of September to the end of April. Berried females (those bearing eggs that will produce the next generation) must be returned to the river, and the bag limit is 5 crays per person per day. But in many popular fishing spots it is getting hard to find legal sized individuals, and fishers are naturally tempted to take animals that are nearly legal so that their day on the river is not wasted.

These declines are not new. In Victoria the fishery was closed in 1983 in response to low catch rates, but it was reopened again in 1991 with a range of restrictions, including the minimum size limit of 9 cm OCL (occipital-carapace length, or the distance between the eyes and the base of the tail).

Our research on the Murray crays in the Ovens River compared catch rates over many years with a survey in the 2010 season. This included contacting and seeking comments from people who fish for Murray crays. We found an alarming decrease in the number of animals in the river as measured by number caught per net lift (or catch per unit effort). Perhaps more concerning was that the 91 fishers who responded to our survey agreed that the catch rate had decreased, the animals were smaller, and it was increasingly difficult to reach their bag limit.

More poignantly, some of these fishers rang us to express their dismay that they were still allowed to do this. Some reported that they had voluntarily stopped fishing and hung up their nets. Now they have a chance to report directly to the people who control the regulations.

The Fisheries Scientific Committee of the Department of Primary Industries in NSW is seeking public submissions on a proposal to list the Murray cray as vulnerable. This will not lead to an immediate closure of the fishery, but it will protect their habitat. Submissions are due next week on 21 December.

Fishing pressure did not wipe out the crayfish in South Australia, a change in the river’s conditions that did that. River regulation, droughts and even floods have impacted Murray crayfish populations. So fishing pressure is not the only cause of decline, but it is one of the few contributing factors under our control.

Low oxygen conditions caused by floods last year meant that Murray crays were walking right out of the river, which got everyone’s attention. I went on local TV to tell people not to gather them up for a feed, because some folk made the assumption that the crays were dying. Unlike fish, crayfish have gills that can function out of the water as long as they remain damp. These crays were catching their breath and could return to the river as long as they were not attacked. The truth was that birds and other predators probably had more of an impact than people. Everything, it seems, likes to eat crayfish.

I will be putting in a submission about the Murray cray and urge others who have appropriate local knowledge to do the same. Use this link to make your views known about this iconic and apparently delicious species. I say apparently, because I have never eaten one myself.

For me, it would be like eating a unicorn.