From Amazon to aquarium

Recently I was one of eight volunteers on a project which researches a cottage industry unique to the Rio Negro, a mighty tributary of the Amazon.

Much of each day was spent in fishing, carried out with scientific vigour and serious purpose, our main quarry bein the ornamental fish sought by collectors worldwide.

The aim of the project is "to promote a stable subsistence fishery so that the forest, wildlife and local peoples and the cultures can be preserved."

"An economically feasible fishery at local level would redu the pressure of economic exploitation through deforestatior and hunting. An international fish trade is essential to a sustainable fisher in Amazionia." (Professor Chao).

Except during the hottest part of each day, we were in dugc canoes either netting or trapping fish, sometimes in mid stream and often in the flooded forest itself.

In the river we cast nets at different levels, recording at eaci one the temperature, pH and degree of oxygenation of the water and the depth and speed of the river.

The main stream fielded turtles, catfish and piranhas, and Chao wishes to encourage the fishermen to catch such edibi fish too, especially as species new to man constantly appeai but it was close to the banks and amongst the trees themsel~ that the ornamental fish were found.

The fishermen are Indians" of mixed stock working from tiny clearings on the river banks. Once a week their catch taken to the market town of Barcelos, where they are trans shipped to Manaus for export.
Approximately 40 million of these tiny fish are exported annually (although about 30% die in transit) and the questionarises as to whether such fishing is sustainable. Chao thinks it is, but he is concemed at the long-term question raised by the poor financial retums accruing to the fishermen who receive about $4 per 1,000 fish delivered, whereas we pay about that sum for each fish (for particular rarities it can be 20 or 30 each!).

It is no wonder that some of the forest dwellers are either beginning a "slash-burn" policy to augment their meagre
incomes or drifting into Manaus to join the regiments of slum r dwellers there.

Chao treads a tightrope, therefore, between overfishing on the e one hand and the locals' grinding poverty on the other. He is also up against the cheaper commercial farming of these fish in the States and elsewhere.

I enjoyed it all. We saw caymans and dolphins, stingrays and little electric eels, enormous spiders, many birds from huge black vultures to brilliant kingfishers, butterflies of every size and colour - a great working natural holiday.

HughMiners

Rio Negro, Amazonia - Jose instructing us on how to fish in an igarape (forest stream). Photo: Hugh Miners


Nature notes

Swifts are among the last breeding migrants to arrive in this country. This is because the insects they feed on are not lar or abundant enough until the middle of May. The birds nee to replace their energy after a flight of over 10,000 miles.

Other small birds arriving in this country take a big gamble with the arrival date. They must time their nest building an later the rearing of their chicks to coincide with the maximu crop of insects. In a cold spell, causing a late spring, the number of successful clutches is greatly reduced.

Birds of prey such as owls are very laid-back. They are usually the first birds to begin nesting early in January, but some years, if food species are scarce, apparently by mutual agreement they don't bother to nest at all.

Probably the worst nest builders in the entire animal kingdom are the pigeon family. Usually a few sticks laid across a branch are all the parents bother with. Many eggs never hatch at all, simply because they fall out of the nest! All the pigeon family are like this, from the common wood pigeon right up to the giant Victoria crowned pigeons of New Guinea. It is thought that this might be because they are descended from birds that were originally burrow-nesting.

Among the most elaborate and most successful nests of our native birds are those of the long-tailed tit. The delicate, bag- like nest is made of moss and cobwebs. Inside may be between seven and fourteen eggs.
MarkHanson
Editor's note: We welcome contributions from our members on any aspect of nature; articles of this size - less than 300 words - are easiest to fit in, but I can arrange space for a longer feature if you talk to me before wnting it.


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