Posted on June, 27 2014

Interviewed by Jorge Oliveira Dantas

Biologist Rosalvo Duarte Rosa was a member of the technical staff of the Rio Juruena Migratory Fish Species Expedition conducted by WWF in May. He lives in Alto Floresta in the north of Mato Grosso state and has considerable knowledge and experience of the Southern Amazon, which embraces parts of the states of Amazonas, Rondonia and Mato Grosso. He spoke to WWF team about the expedition’s work and the importance of conserving fish species in the region surrounding the Juruena National Park.

Part of the expedition’s work involved monitoring the fish species. How was that done in practice?

We captured 20 specimens of the matrinxã (matrinsham) species (Brycon amazonicus) in the vicinity of the great waterfall known as Salto Augusto, inside the Juruena National Park limits. 10 specimens were caught above the falls and 10 below. The fish specimens were sent to the laboratories of the Federal University of Mato Grosso where they are now being analysed. We want to find out whether the two fish communities separated by the falls have exactly the same genetic characteristics and therefore belong to a single community or whether there are differences between them and they are in fact two distinct communities of the same species.

What is the importance of this work?

It is very important insofar as it enables us to determine the conditions of this species at this moment. In that way we will obtain information and knowledge of the species that currently does not exist. It means that in the future, in the event of hydroelectric projects being implanted in the region, for example, we will have baseline references that will help us to determine what may to happen to these fish populations.

Do have any idea when the work will be finalised and when the results of the study will became available?

Possibly we will have some answers by the end of July or the beginning of August.

How will people be able to access the research results?

This research will probably be the object of a scientific article and it is highly probable that something will be published online as well so that the results can be made available to as many people as possible.

Why is it so important to study the migratory fish species of the Juruena region, like the matrinxã, for example?

Migratory fish species have an important dependence on undisturbed natural conditions, an integral habitat. It means that if we detect the presence of various migratory species here, we can be reasonably sure that the area has maintained its natural integrity and has not been degraded by human activities. Furthermore, these migratory species play an important role in the food consumption of the local riverside dwellers. The migratory fish species are the main component of local people’s diet. That means it is important to know all about them, preserve them and do everything to prevent their extinction, thereby avoiding a serious problem for the riverside communities

If something serious were to happen that jeopardised migratory fish species on a large scale, how would that affect the local riverside communities?

It would mainly affect their food supply because these fish are the basis of the diet of all peoples that live along the riverbanks. Anywhere you go you find people mainly eat fish and farinha (manioc meal). If you interfere with the migratory flows of these fish species then you will be removing them from the places where they can usually be found and caught by fishermen from the local communities. The first impact would be to make it hard for people to catch the fish that are the basis of their subsistence consumption and that would seriously jeopardise the lives of people living in these communities.

Still on the subject of interfering with migratory patterns: would there be any impacts on the economic activities carried out in the regions surrounding the Juruena National Park?

Yes, there would. We know that the sport angling lodges, which obviously depend on the presence of these fish, hire people from the local communities as guides and boatmen for the tourists that come to the region. So this tourism offers a source of employment and income to the people that live long the river banks. If the fish were to disappear, so would the jobs.

Would it be possible to say that the amount of fish present in the Juruena River today is less than the amounts registered in previous years?

Yes, we can already observe that there has been an impact. However, the Juruena River is not being affected so badly as the Teles Pires River where the reality is one of intensive agricultural production and large-scale plantations and the silting up of water courses is far more serious and extensive. In the Juruena, those processes are still incipient and their impacts have been smaller than in other regions. However, great care must be taken to ensure that there is no destruction of forest and river banks and no silting up with reductions in fish numbers.

Do you think that Brazilian society as a whole manages its rivers and other water resources properly?

No. I think people need to pay a lot more attention to this issue. We can see, for example that there is a clearly defined policy of building big dams and hydroelectric installations without due assessment of the real impacts of such large-scale works. The Amazon has now become the target for the installation of such large scale hydroelectric projects, but I cannot see evidence of any concern for what is happening to the populations that reside in the areas surrounding them and who depend on all the resources found there. When you build a dam you generate an impact, above all, on the area’s fish, and that is a matter for serious concern. There are plans to build eight hydroelectric plants in the Tapajós River basin. All the riverside and regional communities from Jacareacanga to Barra de São Manuel and right up to the headwaters of the Juruena will suffer the consequences, just as the people living in the Teles Pires region are suffering today.