cape york Archives - Sharks And Rays Australia

A long awaited delivery

by Barbara | May 27, 2021 | Blog | 0 comments

by Nikki Biskis

Our cases are settling into their new homes quite nicely. With over 20 completely built and in various stages of delivery, we should have these displays up and interactive by the time roads open up after Far North Queensland’s wet season.

Since SARA began collecting sightings from the public in 2016, we have received over 140 sawfish saws in donation. After being DNA sampled and morphometric data taken, the saws are destined for display cases, with a select few reserved for educational talks and trainings. With funding from Queensland’s Chief Scientist’s Advanced Queensland Citizen Science Initiative and Save Our Seas Foundation, we are able to put up a case in almost every roadhouse between Cairns and the tip of Cape York. The goal of these cases is to inform communities about how to safely release sawfish from fishing gear and report sightings to us. This sightings information is used in collaboration with many other sawfish groups across Australia in develop status assessments and conservation measures.

During a trip up to Laura in March 2021, Barbara and Nikki from Sharks And Rays Australia delivered the first 5 display cases to their final locations and Nikki got to finally meet the people she’s been talking with for over a year. As always, the country is gorgeous, but people are what make experiences special. Everyone so far has been incredibly supportive of the mission to save sawfish and excited to have a case up on their wall.

The extra 40 kms to Hann River were well worth it. Rob, Renee and Ozzy (their emu!!) welcomed us out of the rain and we found an amazing spot for the display – front and centre. It’s one thing to see cases printed and built, but another to witness them being mounted for all the visiting recreational fishers to see. Finally, we headed back down to Cairns, stopping in Laura for a sawfish training with the Laura Indigenous Land and Sea Rangers and school visit – and leaving them with the final case at the Laura Roadhouse.

Over the next two months, it only gets better. Display cases have been sent all the way up to Bamaga to be exhibited at the Bamaga Tavern, out to the Daintree Discovery Centre, and even to the Northern Gulf Natural Resource Management Georgetown office. If you’re heading up to Far North Queensland for fishing – you can’t miss them! A special thanks goes out to our intern Maddi Jones for building the last round.

Then, an opportunity like no other! Barbara and Michelle flew to Adelaide at the end of April to present a case to the Rodney Fox Shark Museum, which will open within the next 6 weeks. Fellow elasmo lovers are sure to hear about the opportunity to send in their sightings now.

There is still much to come. We’re partnering with Indigenous Land and Sea Rangers to bring cases to the land where sawfish are still seen, and to the Traditional Custodians that watch over them. In addition, we are currently working on designs for our larger saws – some up to 1.5 m – for museums and wildlife centres in Queensland, including Australia Zoo, the Karumba Barra Discovery Centre, Sea World Gold Coast, and Kronosaurus Korner. After all, for animals this charismatic, theses saws deserve to be seen in the correct context, better some catch on the wall of the pub. They are a piece of Australian history, and hopefully an example for how citizen scientists came together to keep them a living icon. We cannot wait to see the sighting reports that come through as result of this project, bringing crucial data to building a more complete picture of sawfish species distributions in Australia.

If you are in Australia and would like to donate your sawfish saw to SARA, or report a sighting, head over to www.cytags.com.

A rare insight into the habitat requirements of large Aussie sawfish

by Barbara | Jan 21, 2020 | Blog | 0 comments

By Barbara Wueringer

Sawfish are very unique creatures, which sometimes poses problems when working with them. The saw of a large sawfish can easily be one the biggest safety hazard you will face during fieldwork. But these animals have another adaptation that has made it difficult to attach tags to them. As the animals often come into shallow waters they have the ability to loosen up their dorsal fins, allowing the fins to fall on the side.

When I worked with captive largetooth sawfish (locally in Australia known as freshwater sawfish) Pristis pristisa decade ago, I realized that in situations that I interpreted as likely stressful for the animals, their two dorsal fins would not stay upright anymore. In captivity these situations included water changes where the water levels in the tanks were first dropped and again raised.

In the wild, when juvenile sawfish venture into shallow waters of 20 cm depth or less, they could easily fall prey to terrestrial predators such as wedgetail eagles, which can reach a wingspan of 2.8m and are commonly encountered in the outback, and near rivers in Northern Australia. This means that it might not be stress, but the low water levels that caused the fins to drop!

The floppy fins pose some difficulties to attaching satellite tags to the dorsal fins of sawfish. The last time that sawfish in Australia, according to our knowledge, were tagged with satellite tags was in 2008 (Stevens et al. 2008). The authors tagged 7 sawfish (5 P. clavataand 2 P. zijsron) with SPOT tags that were bolted to the tip of the dorsal fins of sawfish. These tags are commonly used on sharks, and they can only connect to a satellite and send a location point when the dorsal fin breaks the surface. Additionally one pop-up satellite archival tag was put on another P. clavata. While the PAT tag provided depth data and popped off from the animal after 49 days within a few km of the tagging location, the SPOT tags only provided a handful of locations each (Stevens et al. 2008).

Dr Wueringer holds a towed SPOT-253 tag from Wildlife computers that has been attached to a sawfish. Note the first dorsal fin of the animal falling to the side.

The dwarf sawfish that has been tagged is ready to be released.

Since then, satellite tagging of sawfish has come a long way, and thankfully with the information provided by our American colleagues, our tagging has been more successful. They successfully trialled the methods of attaching towed tags to large smalltooth sawfish Pristis pectinata (for more info see Carlson et al. 2014, Guttridge et al. 2015, Papastamatiou et al. 2015) and shared their set up with us.

The next challenge for us was to find sawfish that were healthy (i.e. did not have their saws amputated) and large enough to tow the tags. In March 2019 it finally all came together and we were able to deploy two of our towed SPOT (smart position and temperature) tags! The first one was deployed on a 280cm long, and likely sexually mature female, Dwarf sawfish Pristis clavata and within 24 hrs the second tag was deployed on a 300cm long juvenile green sawfish Pristis zijsron.

One tag detached after about 3 months while the other one stopped sending location data 10 months after deployment. However, while the analysis and project is still ongoing, we can already see that the data we have received is amazing.

One of the most important outcomes of the tag deployments is that we were working with a commercial fisher on this expedition, who now knows how to deploy tags for us and is excited to do so. So we hope that the next tags won’t have to wait another 3 years to be deployed, as we all work together to find large sawfish.

This image shows a subset of the raw location fixes that we received from our tagged green sawfish. Each dot represents a location fix. Location fixes can have errors (including land based locations), especially when a tag does not surface long enough to send its data to the satellite.

This project has received funding by the Save Our Seas Foundation, the Seaworld Research and Rescue Foundation Inc., the Shark Conservation Fund and the Sydney Aquarium.

This blog post was originally written for the Save Our Seas Foundation. you can access the original here.

References

Carlson, J. K., Gulak, S. J. B., Simpfendorfer, C. A., Grubbs, R. D., Romine, J. G. and Burgess, G. H. (2014). Movement patterns and habitat use of smalltooth sawfish,Pristis pectinata, determined using pop-up satellite archival tags. Aquatic Conserv. Mar. Freshw. Ecosyst.24, 104-117.

Guttridge, T. L., Gulak, S. J., Franks, B. R., Carlson, J. K., Gruber, S. H., Gledhill, K. S., Bond, M. E., Johnson, G. and Grubbs, R. D. (2015). Occurrence and habitat use of the critically endangered smalltooth sawfish Pristis pectinata in the Bahamas. J Fish Biol87, 1322-1341.

Papastamatiou, Y. P., Dean Grubbs, R., Imhoff, J. L., Gulak, S. J. B., Carlson, J. K. and Burgess, G. H. (2015). A subtropical embayment serves as essential habitat for sub-adults and adults of the critically endangered smalltooth sawfish. Global Ecology and Conservation3, 764-775.

Stevens, J. D., McAuley, R. B., Simpfendorfer, C. A. and Pillans, R. D. (2008). Spatial distribution and habitat utilisation of sawfish (Pristis spp) in relation to fishing in northern Australia. 26.