By David Crook
A field trip in November last year to the remote Roper River estuary reminded me that the best experiences in life often arise from adverse circumstances.
The field trip was part of an acoustic tracking study of barramundi and forktail catfish that myself and Lachie Hetherington (PhD student) from Charles Darwin University are undertaking in collaboration with the NT Department of Land Resource Management and NT Fisheries, with help from the Yugul Mangi indigenous rangers.
The Roper River – which flows into the western Gulf of Carpentaria – is one of the Northern Territory’s few perennial rivers, and has been earmarked as a potential candidate for future water resource development. The aim of our project is to provide information on the movements of barra and catfish in relation to river flow, thus helping water managers to make informed decisions about the potential effects of future water resource development on the ecology of the system.
Prior to our trip to the Roper estuary, the research team had spent three epic weeks in the freshwater reaches catching and surgically implanting transmitters into 80 barra and 20 catfish, as well as installing an array of 26 acoustic receivers. We were “forced” to catch the fish by angling because the conductivity of the system is too high for the NT Fisheries electrofishing boat to work effectively. We had a nice shady camp and a place to take a quick dip in the river without fear of being eaten by one of the local lizards. However, the “build-up” weather was very hot and humid and the days long and tiring. As much as I love my fishing, I’d had enough of chucking lures for barra by the end of the three weeks (gladly, this was a temporary condition, resolved immediately upon my return home).
With the fish tagged and the freshwater acoustic array installed, the next step was to cover the estuary with receivers before the wet season rains arrived. We had 12 of the new acoustic release receivers from Vemco to install and the aim was to place one every 10-15 km along the 150 km of river and estuary below Roper Bar. We set off early on a hot and sunny day in November from the boat ramp at Ngukurr (an aboriginal community 30 km downstream of Roper Bar). Chris Errity from Fisheries was skippering the NT Fisheries boat with Lachie and myself on-board. Clarry (the head ranger) and two other Yugul Mangi Rangers were leading the way in their boat.
Our plan was to travel the 120 km from Ngukurr to the estuary mouth – a journey we estimated would take about 3.5 hours. Once there, we would have time for a quick fish (during our lunch break of course) and then return back upstream dropping the receivers in as we went. Two and a half hours into the journey and about 30 km from our destination, all was going to plan. I was enjoying the scenery and beginning to doze off to the thrum of the outboard. Chris was following the rangers as they adroitly avoided hazardous rock bars.
Suddenly, the thrum of the engine became a whine and very rapidly a disturbing squeal. Chris stopped the boat and it was immediately apparent that we were in a spot of bother – out of nowhere we had a blown gearbox. A few expletives followed, but I must say that we all remained pretty calm. Thankfully, the rangers had been keeping an eye out and turned around quickly to see why we had stopped. Given the situation, it was decided that the only course of action was to continue towards Port Roper, with the rangers towing our boat the remaining 30 km.
Now, covering 30 km under tow is a slow and boring process, even with the advantage of wonderful scenery. It took us another three hours to reach Port Roper. It was with great relief that we all sat in the roasting sun to eat our lunch beside the tree-less boat ramp. The issue now was what to do next. We had done plenty of calculations on the amount of fuel required for the trip. However, this did not include spending three, fuel-guzzling hours towing another boat. The rangers’ boat now did not have enough fuel to return to Ngukurr. Of course our boat still had heaps of fuel, all locked up safely in the under-floor tank and completely useless to us.
Fortunately, Chris knew one of the local crabbers (Vu Van Nguyen) and was able to borrow 100 L of fuel to save our bacon. Although it was now mid-afternoon and a long way back to Ngukurr, we decided to do what we came to do and get the receivers in the water. All fuelled up, I jumped in the rangers’ boat and we headed 10 km further downstream to the estuary mouth to deploy five of the receivers. By now the sea breeze had kicked in big time. Rather than deploying the receivers in the calm morning conditions as planned, we got smashed by huge waves. Still, at least some receivers were finally in the water.
I was then dropped back at the boat ramp where the plan was for Lachie and I to mind the disabled boat at Port Roper until Chris could get back to pick us up. Chris’ journey involved a 4 hour return boat trip to Ngukurr with the rangers (dropping off the remaining receivers as he went), followed by another 3 hours of driving on dirt roads at night back to Port Roper. He also had to grab a feed and 100 L of fuel to pay back Vu. Given the stifling heat, increasing numbers of midges and impending darkness, I wasn’t looking forward to 8 hours of waiting around at the exposed boat ramp until Chris returned. I didn’t even have a book to read!
At this point, our luck changed for the better. Vu came down to the boat ramp in his old Landcruiser and asked if we’d like to come up to his shack for dinner and a few beers. Of course we very happily agreed and within a few minutes were kicking back with icy-cold cans of XXXX Gold. Absolute bliss! I was now starting to think that Chris had definitely got the rough end of the deal.
From the outside, Vu’s corrugated iron shack on the river bank looked pretty dodgy. However, once inside it was really well set-up and surprisingly cool. We spent the rest of the afternoon and evening chatting with Vu and his wife, and enjoyed a superb Vietnamese dinner. Vu came to Australia from Vietnam as a refugee in the 1970s and has been fishing commercially ever since. His knowledge of mud crabs and the Northern Territory was amazing, and he was very interested in the sort of research we were doing. It was one of those great experiences that don’t come along too often, and I felt very privileged to have had the chance to spend time talking with Vu in this unique setting.
At about 11 pm, Chris pulled up outside the shack after his epic journey. We thanked Vu and returned his fuel, then headed to the boat ramp to pick up the boat. Getting the boat back on the trailer without the motor (in the dark, in crocodile infested waters) had its moments, not helped by the fact that the winch had broken on the corrugated roads into Port Roper. Somehow we managed and were just about to hit the road when another vehicle showed up and started to launch their boat. I couldn’t believe it. Out in the middle of nowhere at 11:30 pm, these guys just pulled up ready to go fishing. The lengths people will go to chasing barra is astounding!
After another three hours of corrugations, we finally arrived at our accommodation at Roper Bar at 2:30 am, totally exhausted. After everything that had happened, I now look back and think about the awesome experience of that day. Our epic boat trip down the beautiful Roper River, all new to me. Lunch on the banks of the river with the indigenous rangers, talking about their spectacular country. Hanging out with Vu in his shack with cold beer, a delicious dinner and great conversation. Getting the work done despite the challenges. Sharing this all with great colleagues.
Just another day at the office? Hardly!
 Port Roper is located about 10 km from the mouth of the Roper River estuary. If you are envisaging a scene of bustling activity with ships, cranes and wharves, think again. Port Roper is a boat ramp and a handful of fishing shacks.