THE ANGFA RAINBOWFISH

Dr. Gerald Allen, Western Australian Museum

First Published: September 1994, Fishes of Sahul: Volume 8/3

I could scarcely believe my bad luck. Already two weeks had passed and still no rainbowfishes collected. The year was 1989 and I had travelled to remote Irian Jaya as a member of a conservation survey team sponsored by the Asian Wetlands Bureau and the Indonesian Forestry Department. Our primary task was to assess the rich mangrove environment of Bintuni Bay, reputed to be the largest in the vast Indo-Pacific region.

Besides myself, the team consisted of Dutch ecologist and team leader Paul Erftemeijer, and two Indonesians from the Forestry Department, Zuwendra and Sergius Kosamah. This was an expedition like no other that I had experienced. It was my first serious foray into the mangrove habitat, where conditions were extremely difficult at best and sometimes totally impossible. It soon became obvious why there is very little known about mangrove fishes. It's an incredibly alien and hostile environment. The thick gooey mud and nearly impenetrable tangle of prop roots makes travel on foot, even for just a few metres, a major ordeal. Worse are the hoards of sandflies and mosquitoes, which literally form clouds around you. The sandflies, locally called "agas" were particularly bad, inflicting extremely itchy bites on any exposed skin and also penetrating hair and beard.

At times, it seemed that the prospect of sleep, or more accurately, the lack of sleep, was a cruel joke. Sandfly bites, cramped quarters on rock-hard bamboo sleeping platforms, and surprisingly cool conditions (sometimes accompanied by rain) when out in the open all conspired to make night time a necessary evil that had to be endured. In spite of these hardships the work was extremely rewarding. Not only did I learn a great deal about mangrove fishes, but also a considerable amount about other organisms that frequent this habitat. We also gathered valuable information about the vegetation, including some of the largest (up to 3.5 metres in diameter) individual mangrove trees so far recorded. Additionally, Paul and I compiled a list of birds of the Bintuni region (90 species) that we eventually published.

Although the survey was primarily concerned with mangrove habitat I finally had a chance to chase rainbowfishes during the third week of the expedition. At the beginning of the survey we had hired a 6-metre long motorised canoe, along with a crew of four local villagers. Now back at our Bintuni Village headquarters we prepared for the week ahead. The boat was loaded with fish collecting and survey equipment, as well as plenty of drinking water, a large bag of rice, and extra fuel drums. Hopefully we would be able to buy fish and vegetables at villages along the way to supplement our meagre provisions.

For the first three days we conducted survey work in the mangroves at the eastern end of the bay. On the fourth day we motored up the Yakati River, virtually the only large water course draining the narrow isthmus just east of the Vogelkop Peninsula. The immediate destination was Yakati Village, an hour upstream. Our plan was to overnight there and recruit guides for a three-day trek across the isthmus. Judging from the throng of curious onlookers, visitors were a rarity in these parts. About 50 men and boys greeted us on the river bank and closely followed us up the narrow track leading up to the village. There was standing room only as a 10-deep wall of humanity crowded in around the small hut when we ate our meals. I was followed by mobs of kids wherever I went, including into the bushes for toilet purposes or to the local creek to have a bath. Our celebrity status definitely had its drawbacks!

I could hardly contain my excitement the next morning as we shoved off from the bank. There has been precious little fish collecting in Irian Jaya, but the Yakati region had never been touched. I knew that if we could find some good streams there would surely be new species to collect. After about two hours the river became considerably narrower and our progress ms eventually halted by fallen trees. While unloading the gear Paul instructed the boatman to rendezvous with us at this same spot in three days time.

We set off through the jungle on foot in single file. The four of us were accompanied by three guides and one of our crew members. Initially the going was easy, but the terrain soon steepened and the luxurious topical vegetation closed in. Feeling like a 3-year old on its first outing with roller skates, I stumbled and fumbled over the damp, greasy rock, logs, and vegetation that littered our path. I couldn't believe the agility of the guides. They were barefooted, yet kept a brisk pace while hacking continuously at the thick vegetation with their machetes. Leeches were common on the forest floor. I marveled at the way the guides deftly flicked them from their skin with the machetes, without even breaking stride. I constantly brushed my shoes and pant legs to dislodge these unwanted hitchhikers. Occasionally I would notice a stinging sensation and discovered that one had succeeded in attaching itself. Poor Sergius suffered the indignity of having one attach to his scrotum via a hole in the crotch of his track suit. Evidently it had been there for some time as it was grossly inflated. Ouch!

After several hours we approached the first creek. I could hear roaring rapids from at least a kilometre away. Ten minutes later we located a beautiful, crystal clear stream shrouded in dense rain forest. From the bank next to a 2-metre deep hole I saw a number of very large, bright yellow rainbowfish that I immediately assessed as a new species. I wanted to stop and collect but the others talked me out of it They reasoned that we would have to return via the same route and therefore should wait and collect on the return journey. In other words the fewer items we had to carry the better. I knew their logic was sound, but it took a real act of willpower to follow this advice!

By late afternoon we were well into the interior. We stopped at an abandoned sago-gatherers "pondok" (camp), situated on the edge of a small grassy clearing surrounded by tall mountains. While our guides prepared a sleeping shelter, Sergius and I explored the immediate vicinity in hopes of finding rainbows. This effort was rewarded about 30 minutes later when we discovered a narrow stream in dense forest that we dubbed Pondok Creek. Rainbows were plentiful in the deeper (to 1.5 metres) sections. As there was no hope of transporting live specimens I decided to use rotenone. Sergius blocked the 3-metre wide creek with a small seine while I slowly poured in the chemical mixture 100 metres upstream. We spent the next hour scooping up the stunned fish with dip nets. The collection yielded about 150 specimens of an unrecognisable Melanotaenia. The only other fish present was the widely distributed gudgeon, Oxyeleotris fimbriata.

The only food on this trek was rice and peanuts. Therefore when Sergius and I returned to camp with our rainbowfish catch one of the guides asked if I would donate some of our catch for the evening meal. I had plenty of specimens, so why not? Having studied rainbowfish for 15 years, I had never bothered to investigate their edibility. Our cooking facilities were pretty crude. Aside from a large pot for preparing rice and boiling water we lacked both utensils and plates. Instead the food was served on broad green leaves and was eaten with our fingers. The rainbows were boiled and served whole. If you haven't tried them my advice is don't! They were definitely bad news. Due to a diet consisting largely of ants that fall onto the water's surface the flesh was strongly permeated with the taste of formic acid.

It was our original intention to completely traverse the isthmus from sea to sea. However, the weather closed in on the first night and it rained incessantly. Rather than risk the crossing in treacherous conditions we decided to spend an extra day and night at the pondok. This gave me a chance to collect at nearby Lake Kuramoi, where I was successful in finding yet another new rainbowfish.

That evening back at the pondok I was dismayed when one of the guides informed Paul that he did not want us to collect at the creek we had crossed on the first morning of our trek. He explained it was a sacred site and it would upset the spirits if we fished there. This was indeed bad news. Ever since first sighting it I had constantly relished the thought of collecting the new rainbow on the return journey. I retired to my cramped section of the mosquito-netted sleeping platform feeling frustrated and angry.

The next morning we broke camp as soon as we had sufficient light. Slowly, in much wetter conditions than the inbound journey, we retraced our route to the Yakati River. Paul knew how strongly I felt about collecting at the creek which had suddenly been declared off limits. He must have read my mind because he warned me that it would be unwise to linger behind the party and then stop to make a quick "undercover" collection. I promised not to do this.

I was pleasantly surprised when we arrived at the creek and was told that the guides had reversed their original decision. They said I could not use nets or rotenone, but was welcome to try with a bit of handling and a small hook. I immediately tried to find some sort of bait, but was unsuccessful. As a last resort I dropped in a shiny bare hook. Instantly, a large rainbow shot from cover and gulped the hook. I quickly jerked the beautiful 12 cm-long specimen onto the bank and placed it in a water-filled plastic bag. In the next few minutes I caught two additional specimens, using a small, tightly packed ball of rice for bait. Niko, our crewman, caught a small crayfish, which I then used to catch a pair of 18 cm-long grunters. These were the first adult specimens of Hephaestus lineatus, a species I first discovered on the Vogelkop Peninsula several years earlier. I also sighted a 30 cm Tandanus catfish foraging on the bottom, but it would not take the bait

Fortunately I carried a tiny photographic aquarium in my backpack and was therefore able to capture the brilliant live colours of this stunning rainbow on film within minutes of its capture. However, this task was more difficult than you might think. I had left my strobes back at Yakati Village in order to save weight so was forced to utilise natural light. Only a tiny bit of sunlight filtered onto the uneven and well vegetated forest floor. I had to lay on the ground to reach a position level with the fish. Just as I was about to click the shutter the sun would move slightly necessitating a shift of the aquarium. I was finally rewarded with a few good shots after crawling on my belly for several minutes in pursuit of the elusive shaft of sunlight.

The trial and tribulations of collecting and photographing this highly attractive fish were definitely worthwhile. It turned out to be the same species as the one taken in the middle of the isthmus near our camp, although the specimens from the "sacred" creek were much larger and more vividly coloured. Several weeks later I was able to thoroughly examine the specimens back in my laboratory in Perth. It was clearly a new species as I suspected, superficially bearing a resemblance to the Lake Tebera rainbowfish (Melanotaenia herbertaxelrodi). Its description was eventually published in the March 1990 edition of the French journal Revue Francaise Aquariologie. It gave me considerable pleasure to name it M. angfa in honour of the Australia New Guinea Fishes Association. As we all know, this organisation has been instrumental in creating awareness by both government agencies and the general public of the highly unique character of our native fish fauna and the urgent need to conserve the aquatic environment, which is vital for it continued survival. It has been a privilege to be a member of ANGFA over the years and I wish the Association every success for the future.