Battling to eliminate carp from Australian waterways 🐟 | Meet the Ferals Ep 9 | ABC Australia

they're the rabbits of the river our worst feral fish the carp behaves rather like an aquatic vacuum cleaner eventually turning the riverbeds into mud where nothing will grow carp were first introduced to Australian waterways by European acclimatization society's wanting to catch them for food and fun by the 1920s they were well established in the Murray River and while they are a problem in other regions the Murray Darling Basin is where they had the greatest negative impact as a European car release into rivers like this here in Gippsland has been described by the fisheries wildlife department is a great tragedy we are reflected in this nation we are afflicted with this disgusting mud sucking creatures bottom-dwelling mud sucking creatures these bottom dwellers do indeed muddy the waters and with as much as 90 percent of the aquatic biomass now carp they also starve native species of their food while there's millions of baby carp mouths eating the same thing as the baby native fish there's a lot of competition since the 1970s many methods have been employed to get rid of them some pretty rudimentary others a little more high-tech it's called electric fishing and it's proved highly successful they've been fished to make fertilizer all been snap frozen before we get it these are probably come from down in South Australia or perhaps from the Gippsland lakes and throughout the carp infested waterways they've been caught for human consumption there's a lot of people think you can't eat carp and you absolutely can't eat car commercial fishers Glenn and Tracey Hill have tried to convince skeptics it can be a tasty treat if you look after it do it right I understand what you got to do to process it it's a brilliant fish it's the most farmed fish in the world so billions of people in the world can't be wrong the fish itself is actually pretty versatile the swim bladders can be used as fining agents in winemaking and there's even a use for the skin the skins now used in leather products that'll range from things like purses to belts to wallet those sort of things we're just in the process of commercializing it now and with carp producing massive amounts of eggs up to 15% of their body weight the road has a market in Europe there's a poor person's caviar the big old don't fish are the ones that are really good for us for the road but the bottom line for these bottom feeders is it's difficult to substantially reduce carp populations by simply catching them partly because they are such prolific breeders one three kilo carp for example will lay three million eggs in a normal year and in a good year when breeding conditions are right they'll do it another spawning so you've got this massive numbers of eggs from one fish netting is the main method of capture primitive and effective but it has limitations the more you catch the harder it is to find those that remain so a decade ago the more scientific approach was attempted okay these aren't an osmotic pump you inject hormones or other chemicals into it and it slow releases at over a period of two weeks female carp had small pheromone pumps surgically inserted then they were put in a cage as a live lure for male fish the trials eventually found the invasive procedure wasn't cost-effective as it didn't attract enough male fish another process in which fish had radio tracking devices attached has been more successful well that was our first Judas Cup of one of 12 that were releasing the lake and he's got a radio transmitter on his back in over the next two years he'll lead us to his friends and family when the carp aggregate for spawning overwinter the Fisher's can go in and catch the masses of fish it's a technique that helps reduce carp in two large tasmanian lakes male fish implanted with GPS trackers were followed to the spawning spot and teams electro fished sending small electric currents through the water to stun the fish for a few seconds allowing enough time to check whether they were actually calm so how'd you go carp control in Lakes Sorrell and Crescent has been so successful that it's difficult now to find the fish it's very different to the old days I think our best day back in 2012 was a 750 carp in a single day now this season we've got three carp in four months we spend a lot of hours and a lot of days pulling nets for nothing remarkably after 25 years of concerted carp management funded by nearly 14 million dollars from governments the island state is now considered carp free something the mainland could only dream of the scenario is different here because we've got them contained even though the lakes are big they're contained to one catchment they're not widespread and that was the most important factor and it's part of the reason why the program survived to the point that we're going to achieve eradication one research project that looks promising in terms of helping solve mainland Australia's feral fish problem was the daughter Lascar project in 2000 dr. Ron thresher and his team at CSIRO started testing technology that induces carp to produce only male offspring if we could come up with a a gene construct that we could put into an animal that resulted in all of its offspring being male and all of their offspring being male and all of their offspring being males even then after a couple of generations you'd wind up no females the population would just crash but 2012 the project had been wound up in part because the technology was still several years away from adoption it was a great disappointment to the research team who felt they were close to a solution to an extent and we've proven what we wanted to prove which is that the technology works you know doing it in zebrafish the next critical step is finding out whether it works in carp and if there's a sad bit it's because we're halfway through that experiment and we're going to have to terminate it before we actually get the definitive answer by far the most promising and most controversial carp control measure comes in the form of a virus virus causes high mortality in all age groups of carp and it's common carp and koi carp which are the only two species that are affected by the virus carp herpes virus emerged in the late 1990s and caused havoc in northern hemisphere carp populations it's being investigated as a biological control for carp in Australian waterways once it infects a fish it seems to get into there and many organs and it probably kills them by interfering with the function of gills kidney and gut a 15 million dollar research program called the National carp control plan spent three years looking at the environmental and economic feasibility of releasing the virus it's time to to introduce and and bring in one of the most what I think personally as a scientist will be one of the most effective controls on carp that we can get as a starting point research has gathered baseline population data there's believed to be up to a thousand carp per hectare this is really the first time that there's there been the resources to go out there and get this this total abundance figure and you know it's sort of a Holy Grail other research examined the water quality impact of millions of fish dying in the river they found when they dumped six tons of dead fish into an enclosed wetland the oxygen level dropped which could be lethal to other non-target fish water New South Wales measures the impact of different quantities of dead fish at Prospect reservoir which supplies Sydney about a thousand kilograms per hectare the dissolved oxygen stayed at zero for up to five days and that's a real concern because for such a prolonged period at low zero you're pretty much wiped out the rest of the ecosystem I think the worst-case scenario is that the intention of the national plan to improve native biodiversity could have the opposite effect and actually cause loss of native biodiversity John Conlan works for the International Institute for water education in the Netherlands and believes the virus will actually give native fish a chance to reclaim their territory it will be very short-lived if there is water quality problem and it will be only for one season for a lifetime of benefits the National carp control plan is now in the hands of decision makers the release of the virus will need approval of all the states as well as the federal government we can absolutely close the book on whether or not carp or a problem we know they are we know that they have tremendous environmental impacts and we know that this problem is not going away by itself you

Channel: ABC Australia

Views: 850,857

Keywords: ABC, Australia, ABC Australia, Carp, Carp in Australia, Carp in victoria, Carp in the murray river, Carp in the murray-darling, Carp in Tasmania, Carp fishing, Carp eating, Carp fishing in australia, carp cooking, how to cook carp, carp extermination, how to hill carp, meet the ferals, landline, landline abc, feral animals in australia, pest animals in australia, australian invasive species, feral animals and pests in australia, feral animals, pest management

Id: lvxJVvFiUGY

Length: 10min 23sec (623 seconds)

Published: Fri Apr 17 2020