Playing the food web game

Playing the food web game

In early November 2018, Sharks4Kids and Sharks And Rays Australia embarked on a joint mission to visit schools around Far North Queensland to talk to the kids about sawfish. Throughout the year, we had finalised developing our ‘North Australian Food Web Game’ and as part of fieldtrips we had already visited the Kowanyama, Old Mapoon and Normanton State Schools. The visits to Kowanyama and Old Mapoon were our second time in these schools, and some of the kids remembered us and how to tag fish, which is fantastic news.

The aim of the school visits is to introduce our work, and the importance of sharks and rays in the local ecosystems, to the kids. We often visit state schools and aim for schools that are off the beaten track. The local Indigenous children often spend time ‘on country’ with their families, often hunting and fishing. Some of their parents work for the local Indigenous ranger groups. But sometimes these parts of their lives are separated from what they learn in school, and so we aim to connect what they see in their free time with ‘boring science’.

I am proud to stand in front of all these little girls and boys as a female scientist. Fieldwork oriented elasmobranch science is clearly a male dominated field, and so every woman in this field is also a #WomenInSTEM ambassador for #GirlsInSTEM. This year, I had 11 other biologists join me on the school visits, and each one of them brought in their own perspectives and knowledge.

For the last visits in November, Paddy Burke, who is currently doing his PhD at Macquarie University, joined me as the representative of Sharks4Kids. Over the duration of one week, we visited schools in Cooktown, Laura, Wonga Beach and Kuranda. Sadly, the Hopevale and Yarrabah state schools did not have time for us. The children that we met were between 4 to 16 years old. In total we spoke to and played the game with 262 students this year. Many of these kids would have never had a chance of meeting scientists before. For example, as the Principal of Laura State School told us, their little town currently sits in the lowest 2% of the socio-economic index of Australia.

Just like, us, the kids love these visits and so do the teachers. Our school visit to the Normanton State School has led to a collaboration in order to develop materials of the life cycle of the freshwater sawfish. During the first term of 2019, the kids will draw these life history stages. The materials will be available on our page, so stay tuned!

This work was supported by the Queensland Government’s Engaging Science Grant, which also allowed us to develop our ‘North Australian Food Web Game’. You can download the game here. It contains colouring in sheets and fun facts of many animals that are found in the rivers of Northern Australia.

The kids from the Laura State School present their coloured in animals from the food web game, together with Paddy from Sharks4Kids and Barbara from SARA

The kids at Wonga Beach State school learn about our research with sharks and rays, including sawfish.

Paddy from Sharks4Kids explains the differences in the four sawfish species that are found in the waters of Northern Australia

A girl from Wonga Beach colours in a saltwater crocodile. Each sheet has facts about the animal on it

During our trip, we were also able to DNA sample some of the saws in private collections

This is my favourite coloured in sheet from our food web game! Some of the kids get really creative while drawing, as visible on this sheet coloured in by a 4-year-old girl from Laura

Accelerometer tags on a sawfishes’ saw

Accelerometer tags on a sawfishes’ saw

 

We were out in the waters of the Mitchell River, near the Indigenous community of Kowanyama. Every day we would wake at 3am ready for a 4am start of setting nets on the river. After a 7hr sampling session, we’d eat and rest and then run another sampling session in the evening, either hand-lining for freshwater whiprays (last year we had also caught a saw-less sawfish like this), or setting more nets.

The first few days we were only catching small bull sharks, which is fairly stressful when gill netting. Sharks don’t do well in gill nets, but in this part of the river, which is freshwater, many of the sharks we had caught over the last three years had a fungus infection visible on their skin. This meant that we had to be even faster releasing them, otherwise they would struggle.

One morning, we had caught multiple juvenile bull sharks in one net, so many in fact that we were continuously checking the net to get them all out so that we could pull the net without injuring them. When the net was finally retrieved, and we arrived back at the camp, we were greeted by a very angry couple waving paperwork at us (in the middle of nowhere) shouting that they had booked this particular camping spot where we had set up our camp. As we did not want to get in trouble with anyone, and our booking had been made by the local rangers who were on weekend break, we had to move. The move took about 3 hrs, and our new camping spot, the only one providing a safe entrance to our boat, also displayed a stark reminder of the presence of saltwater crocodiles (Figure 1).

Fig. 1: Upon assessment of our second camping spot we found this footprint of a saltwater crocodile Crocodylus porosus. Saltwater crocs can be quite dangerous to humans and a colleague from Australia Zoo estimated the owner of this footprint to be over 5m long. Barbara’s foot is a size 38 European. However, during our time at the camp spot this crocodile would have not been able to lift itself up the steep riverbank because of low tides.

After an afternoon nap, everything changed. We all agreed that our new camping spot was better than the old one, and started over. We became friends with our neighbours. There were no more bull sharks in the net, but sawfish! And we were finally able to deploy our custom-built tags. These tags combine an accelerometer, which records the movement of the rostrum in 3D space, with temperature, light and pressure sensors, in a casing that allows the tags to be mounted on the base of a sawfishes’ rostrum. An acoustic tag allows active tracking of the animal and a VHF tag allows us to find the tag once it has detached.

There are many release mechanism for tags in saltwater and they generally involve corrosion. In freshwater this does not work and so we tested our own ideas of dissolvable string. With the ‘perfect’ lab-tested configuration, the first tag detached upon release of the animal (2 mins into a 3 day deployment). We modified the set up, and the second and third tag released after about 4 hrs. The fourth tag finally stayed on (figures 2,3 and 4).

Fig 2: The first accelerometer tag is attached to the saw of a juvenile freshwater sawfish Pristis pristis.

Fig 4: A happy SARA team is ready to release this freshwater sawfish, Pristis pristis, with its tag attached.

With a team of four, and three people required on the boat for tracking, it was difficult to take turns going on land, relaxing and preparing food. After close to 30 hrs of tracking the sawfish, with only 3 hrs of sleep, we recovered the tag. Having worked with sawfish for 13 years, this included one of my most memorable moments of fieldwork. As the tag had not been moving for a while, we decided to head to the side of the river where it was located. In order to not scare the sawfish, I beached the boat further upstream, got out and moved to the high bank under which the tag was pinging. The water was clear and I could see the little sawfish with our tag attached to its rostrum hunting baitfish.

One of our field assistants, Sarah, was so impressed by what she had experienced on the expedition that she even ended up with a tattoo of a sawfish (figure 5). Clearly these animals are not only of cultural importance to Indigenous Australians, but to all of us.

 

Fig 5: Our volunteer field assistant Sarah O’Hea Miller turned her experiences of the expedition into a permanent memory in the shape of a sawfish tattoo.

This blog post was written by Barbara for the Save Our Seas Foundation. You can access the original here. 

Queensland and it’s sawfishes. by Nicolas Lubitz & Barbara Wueringer

Queensland and it’s sawfishes. by Nicolas Lubitz & Barbara Wueringer

written by Nicolas Lublitz and Barbara Wueringer

Sawfish are the stuff of legends: Animals that can grow up to 7 m long and have an extended rostrum (the ‘saw’) loaded with teeth. Old newspaper articles have described them as monsters that lurk in our rivers and oceans and are just waiting to attack people. Quite the opposite is true, as sawfish use their „saw“ skillfully in order to stun and manipulate their fishy prey, not caring for us humans. They are magnificent animals, no doubt.

Anecdotal reports claim that sawfish used to be so plentiful that people in Sudan once used their rostra as fence posts. Additionally, a study from Lake Nicaragua estimated that between 1970 and 1975 around 60,000 – 100,000 animals were caught in the lake by commercial fishers. This was once thought to be their largest population. A survey in 1992 could not find traces of a single individual in the lake.

Today, five extant species are recognized. All are either listed as Critically Endangered or Endangered under the criteria of the IUCN, making sawfishes the most endangered of all the sharks and rays in the world. Four out of those five species can be found in Queensland waters, which are thought to be home to some of their last important populations in the world. With significant global declines for all species, the question arises, if the rivers and coastlines of Queensland are still a stronghold for these animals?

First, we need to engage in a debate about our baseline – how abundant was the species in the past? This search can turn philosophical really quickly. How do we determine a healthy population? What levels do we want the population to return to? Does it need to return to pre-human influence levels or is it enough to keep the population at a level where it can somewhat perform its ecological function? Or is exploitation more important than conservation?

Secondly, we need to determine how much the population of sawfish have declined in Queensland. To answer this, sawfish capture data from the Queensland Shark Control Program (QSCP) was analysed. This program started in 1962 and aims to protect swimmers/surfers from potentially dangerous sharks by utilizing gillnets and baited drum lines. Although no scientific evidence exists that the program actually works, it has been in place for decades.

The data shows that between 1962 and 2016, 1450 sawfish were captured,with 99% of captures occurring in the four most northern areas of Queensland’s East Coast, suggesting the existence of critical habitat. Most animals were caught in the nets and not on drum lines.

An overall decreasing trend in catch rates was observed for two locations where standardized catches could be calculated. However, standardized catch rates from the data set are likely underestimating abundances, as the nets were set up to 500m away from the coast, in deep waters where they often did not reach the bottom. Most sawfish captures occurred near the bottom of the nets.  

The facts of this data set make firm conclusions on abundance declines difficult, although it is apparent that the declines have been statistically significant. We need to devote more resources to better understand population trends in Queensland’s sawfishes.

 

You can access the publication on sawfish catches in the Queensland Shark Control Program here.

This blog post was originally written for the Save Our Seas Foundation. Access the original blog here. 

Standardized catch rates for sawfish (fam. pristidae) in gill nets in two separate locations of the Queensland Shark Control Program, 1962 – 2016. Red stars indicate when fishing began and ceased in the respective location. 

A student internship – Part 2 by Grace McNicholas

A student internship – Part 2 by Grace McNicholas

The next morning, we woke to strong winds and white horses on the river, which up until now had been as flat as a pancake. We later discovered an extreme wind warning had been issued for nearby marine areas, but outside of the reach of even the coastguard this information is not easy to come by. Getting the research vessel out without damaging it against the rocks would be impossible. Additionally, as this river is very shallow, the wind was pushing the surface water downstream, resulting in a prolonged low tide. With no boat ramp, its essential the back wheels of the boat trailer can be reversed into the water at the correct angle so that the boat can be winched on securely. Unable to get the back wheels in deep enough due to the low tide, Barbara suggested accessing a small area on the other side of the river where a commercial fisherman had a semi-permanent camp. Barbara and Julia, who had experience with 4WD, took the Troopie back down the bumpy dirt track. Sitting in our half-dismantled but wind-proof camp and snacking on gingernuts, Annmarie and I waited as the wind howled around us.

Three and a half hours later they returned with bad news. The other area was muddy and soft and with no way to pull the boat out. It was back to the drawing board. The next night we took turns to wake up every hour to check the position of the tide, after marking the sand with numbered increments. My first alarm went off at 1am and after scrabbling around to find my headtorch and pulling on my walking boots, I made my way towards the water’s edge. My heart pounded as I scanned the surrounding area for two glowing red orbs, the infamous sign of crocodile eyes. Phew, no sign of crocs tonight, just the familiar glittering of spider’s eyes sprinkled across the ground. I checked the tide, which was still low, then made a note on our timetable back at camp and tucked myself into my swag until my next check at 5am. A little more confident this time, I headed straight for the shore. Surely, I would find a higher tide? No such luck, the waterline had barely moved.

We discussed our next move over breakfast, which for me obviously involved a good old brew of English Breakfast Tea. The wind had died off and although the tide was still low, we’d have to give it our best shot to get the boat out today. After some skilful driving from Barbara, and some manual re-adjustments from all of us, we finally managed to position the trailer at the exact angle the wheels could go back far enough to get the boat on. A few painstaking hours later and the boat was on the trailer. However, the unevenness of the shoreline meant we couldn’t pull it out without tipping the boat, so back in it went.

Up until now the morale had been pretty high, but the midday sun and exhaustion were starting to get to us all. We agreed it was time for lunch. A can of coke and sandwich later and we were ready to try again. After driving the boat a little upstream, we accessed an area we had previously discounted as there was a large shallow sandbank blocking the boats trajectory to the shore. At first sight we still weren’t hopeful, but with some group perseverance, we managed to guide the boat onto the trailer and winch like crazy! To be honest this part was a bit of an emotional blur and the details are a little foggy. The only thing I do know for sure is I’ll never forget the comradeship and pride we all felt when the back wheels of the trailer finally made it out of the water with the boat firmly attached.

We spent the next night in a campground back in town and were ecstatic over hot showers. We squeezed in one more sampling session in the Norman river (there is a boat ramp!), but despite keeping everything crossed we still didn’t catch any elasmobranchs. As disappointing as this was, unfortunately this is the heart-breaking reality of working with critically endangered species with severely depleted populations. The next day we had arranged to visit the local school to talk about sawfish and the research we were doing. Outreach is an important aspect of SARA and these school visits are a fantastic opportunity to connect what Indigenous kids see when out ‘on country’ with actual science, and maybe even inspire the next generation of biologists and conservationists. The interaction and excitement from these kids was truly heart-warming and gives me great hope for the future.

I’m back in England now, and as I sit here writing this, I can’t help but feel overwhelming proud of myself. SARA expeditions are hardcore, working in some incredibly harsh conditions, with some of the most endangered animals on the planet. From day one of landing in Cairns, to those bucket showers in the outback, this experience has been the most rewarding thing I have ever done; and although I wasn’t lucky enough to see a sawfish, to have even had the opportunity to be involved in a project that could change the fate of future conservation is reward enough. Those two weeks will stay with me forever and it couldn’t be an easier decision for me to sign up for another trip next year.

I’d like to thank Julia and Annmarie for being such enthusiastic, caring team mates and Barbara, the sawfish Goddess herself, for being such a wonderful mentor and friend to all of us.

 

A student internship – Part 1. by Grace McNicholas

A student internship – Part 1. by Grace McNicholas

It’s safe to say, each of us were equally as excited to be part of an all-female team representing women in science. Our international research team consisted of myself (Grace), a visiting Master’s student from the University of York (UK), conducting a two-month internship with SARA, Annmarie, a Master’s student from the University of Mississippi (USA) visiting Australia as part of the #SawSearch project, Julia, an Aussie undergraduate student at the University of Wollongong, and of course Dr Barbara Wueringer, principal scientist and founder of SARA.

It was now the middle of August and I had been in Cairns since the beginning of July 2018. As part of my Master’s programme I was required to complete a two-month placement with an external organisation. I had contacted Barbara earlier that year and was lucky enough to secure a project, much to my excitement! After skyping a few times, and brainstorming some ideas, we decided I would investigate the effect of environmental parameters (i.e. temperature, tide, salinity etc) on sawfish distribution. I would be using data collected by SARA over the last 4 years of river systems of the Gulf of Carpentaria. Of course, as grateful as I was to spend two months in sunny tropical Cairns, I couldn’t miss the opportunity to get involved with some data collection myself, so I booked myself onto the two-week Southern Gulf expedition in August and headed down under.

Barbara welcomed me with open arms and we soon began to establish a daily routine working from her home office. I spent my days working through spreadsheets and analysing data under her guidance. When my eyes started to feel a little bit too square and I needed a break, Mr. Jaxy (Barbara’s adorable dog) was always there for a cuddle. I was loving every minute of working on this project, but I couldn’t wait to get into the field and see for myself how the data I’d been using had been collected.

We met on a sunny Monday morning in Cairns and soon began packing up the Troopie and boat trailer with everything we would need to camp and conduct research for the next two weeks. Stuffed to the rafters we set of on our long drive, headed to Normanton on the west coast of Far North Queensland. From there we made our way to the homestead of the large cattle station we had kindly been allowed to camp on. Now as an English girl, I had no concept of what a cattle station is or how big they are. So, for those of you who like me don’t know, picture an American ranch, cowboys and the lot, then add an Aussie twist. We were greeted by the managers daughter and son who gave us directions to a little dirt track which ran parallel to the river and where we would find a clearing we could set up camp. The kids joined us on a sampling session a few days later and proceeded to make fun of me for accidentally calling mustering ‘herding’ and for daring to worry about crocs and snakes.

We found the clearing, backed the boat into the river, then after a slight mishap involving a lot of mud, furious shovelling and a tow from the station manager, we were finally ready to set up camp. Being a seasoned expert, Barbara has the whole camp thing down to a fine art. We swiftly erected a large gazebo as a cooking and resting area, two privacy tents (one for our bucket water ‘showers’ and the other for our very luxurious drop toilet), and finally our own private sleeping swags. After dinner, we sat around the campfire chatting and marvelling at the night sky, the buzz of excitement growing for the days ahead.

The next day Barbara gave us a research induction and then the four of us set out on our first gillnetting session of the trip. Setting gillnets is an art but after a few questionable first attempts, we soon got to grips with it. Sampling sessions usually consisted of setting two nets, which were checked every 30 minutes. Between checks, we anchored the boat within sight of the nets and kept our fingers crossed we would catch a sawfish, ray or shark. Checking the nets requires some good spatial awareness and team work, carefully lifting the top (float line) and bottom (lead line) out of the water to check the full depth of the net. It’s all hands-on deck during these sessions, untangling and measuring fish, writing down data and photographing animals to assist with later species identification. I went from having no prior gillnetting experience to confidently setting and checking nets after just a few days, testament to being thrown in at the deep end from day one and learning on the go. Most sampling is done very early in the morning or during the cooler evenings, as we choose sampling times based on activity patterns of target species and not our own. We had caught a range of teleost species including bony bream, barramundi and some very cute catfish, but after three days we still had no luck finding any sawfish or other elasmobranchs. We decided to try our luck elsewhere and relocate to different river.

Apparently, the outback had different ideas.

continue to Part 2 here