Water Engagement Roundup
The questions and answers from the Water Engagement Roundup webinar recorded on Wednesday 15 May 2024 are published below. The topic for this webinar was freshwater turtles of NSW and the significance of water management.
Watch the webinar
Wednesday, 15 May 2024. This month, the topic was freshwater turtles of NSW and the significance of water management.
Questions and answers
Does the work of the Commonwealth environmental water holder's Flow-MER program complement, or help inform this work?
A. Yes, our department works with or alongside Flow-MER on various projects. Our Gwydir turtle movement project is connected to Flow-MER's turtle population monitoring through the University of New England.
However, where Flow-MER already has sufficient coverage, we redirect resources to other areas where there is less focus to reduce duplication.
What impact has there been on Darling River turtles following the mass deaths of fish near Menindee? What predictions can be made about the capacity of turtles to respond if the carp virus is released?
A. There has been no targeted monitoring of freshwater turtles in the Darling River, which makes this question really hard to answer. We do have a good understanding of freshwater turtles ability to consume dead fish and assist with decomposition. It is thought that fish kills and the proliferation of carp may have benefited one species: the Broad-shelled turtle. However, this hasn't been substantiated.
What is an ecohydrologist, and how do they engage with other water management areas (irrigation, councils, community)?
A. An ecohydrologist is a scientist who studies the interactions between ecological systems and hydrology.
Our primary purpose is to monitor the effectiveness of environmental provisions in water sharing plans, but we also provide detailed scientific advice on a range of water management issues. This ranges from targeted research to improve our knowledge base to individual pump proposals for water license holders. We are aiming to increase our engagement with the general public and key stakeholders
How do stream impediments such as weirs, barrages and dams affect freshwater turtles?
A. This still remains a key knowledge gap for freshwater turtles. It is assumed that large barriers are just as big a problem for turtles as they are for fish. For example, the major storages in the Gwydir and Namoi Rivers mark the downstream extent of the Western saw-shelled turtle. We have shown that they can move through large regulators, but much more research is required.
How big are the population of freshwater turtles in the Peel River system?
A. There are two recorded species in the Peel River, potentially a third. The known species are the Eastern long-necked turtle and the Murray River turtle. There has been very little turtle focus in this catchment. Only 293 longnecks and 19 Murray River turtles have been recorded in BioNet. There is a general need for more comprehensive surveys across the MDB.
Do you know the official term for our freshwater Terrapins?
A. Historically the term Terrapin had been applied to some turtles across the world. For example in the UK they like to call freshwater turtles terrapins and marine turtles “turtles”. In Australia, all our freshwater species are part of the family Chelidae which are turtles, not terrapins.
Do you know of any Biodiversity Conservation Trust related projects in place for the protection of freshwater turtles?
A. I am now aware of any Biodiversity Conservation Trust (BCT) related projects in place for the protection of freshwater turtles. But we work closely with the Saving Our Species team which are connected to BCT.
How are First Nations concerns and knowledge incorporated into the monitoring and management of turtle populations?
A. Researchers and First Nations groups are working together across the Murray-Darling Basin. Particularly some of our partners: UNE and La Trobe. We as a department need to develop more programs which integrate first nations knowledge of past and current trends in turtle populations, as well as developing a better understanding of the cultural significance of turtles to traditional owners.
What species of turtles were tagged in the Gwydir study?
A. The species of turtles tagged in the Gwydir study were the adult Broad-shelled turtles and Murray River turtles.
Are there ways to change the releases from dams to avoid cold water pollution?
A. The biggest issue regarding cold water pollution is that many of our dams were built to release water from the bottom, which makes sense from an efficiency point of view. But once you start taking water from deeper than about 10m, the temperature drops off sharply. Several options have been explored, from the idea of 'thermal curtains' through to building variable offtake systems which can change the depth at which water is released. The reality is that it's an expensive fix but arguably one of the biggest impacts on many threatened species including catfish. It can mean that water temperatures during warmer months are effectively the same as winter temperatures, which messes up the instinctive cues that many animals and plants rely on as a trigger for breeding and other activities. We also know that fish in cold water polluted rivers are much smaller than in ambient temperature rivers.
So, there is ongoing work to find a realistic solution to this.
Do you use eDNA for turtle presence and absence?
A. The genetic library for freshwater turtles is still in development. We cannot detect all our species yet, but a variety of Universities and private organisations are working on eDNA assays for all species across NSW.
Can turtles use fish ladders?
A. Almost certainly yes, but there is insufficient information to answer this at this point in time. Movement monitoring in the Barwon-Darling River should provide an answer to this question, at least within this system.
Is anything known about possible botulism risks to turtles in relation to mass fish kills?
A. This remains unknown. However, it is unlikely to be an issue for the health of freshwater turtles considering they are natural carrion scavengers and have been for a very long time. They do have the potential to carry or transmit botulism though. See Shelley et al. (2015).
The only article I know of is Shelley et al. (2015) Infant botulism due to C. butyricum type E toxin: a novel environmental association with pet terrapins. Epidemiology & Infection, 143 (3).
Did turtles also die in or around the Menindee fish deaths?
A. Nothing has been reported. If turtles were present (no sampling has been done for a very long time), they would almost certainly be feeding on the dead fish, but may have left the weir pool to avoid poor WQ. They could have died on land trying to avoid poor WQ, which often makes them hard to find.
You can report dead turtles here: TurtleSAT https://turtlesat.org.au/turtlesat/map.aspx
I thought they were known as Tortoise rather than freshwater turtles. Why do we call them turtles now?
A. Tortoise is a terrestrial or land dwelling animal with feet for walking and often a much higher more raise shell.
Terrapin is a northern hemisphere term for freshwater turtles, often used to distinguish between Marine and Freshwater turtles. However, the term Terrapin is rarely used these days.
Freshwater turtles have flipper like feet, often with claws and a much more laterally compressed shell (squished compared to a tortoise). They are a highly aquatic species.
What role does flooding play in dispersing the individuals and changing their distribution?
A. Early evidence suggests flooding and floodplain environments are important habitats for freshwater turtles. We have evidence of male Murray River turtles travelling more than 80km upstream during floods. Taking advantage of the highly connected floodplain to return to a river.
More research is being undertaken to look at how turtles move across the MDB from QLD all the way to SA.
Is it understood what kind of maximum flow rates the Eastern sawshelled turtle can withstand in a major flood event?
A. No, the answer to this question remains unknown. It is likely that most turtles are capable of withstanding large flood events. The shape of their shell would provide a downward force to push the turtle onto the bottom of the channel. Their clawed feed would then allow them to dig into roots and under banks during floods.
It would be great to see this question answered within a flume setup.
What underwater cameras do you use?
A. Any waterproof action camera would work. We use Sony FDR-X3000 and GoPro HERO 12s. However, the cheaper Sony cameras work just as well as the more expensive GoPros