There are six species of crayfish in Madagascar, all are endemic to the island and most are probably threatened with extinction. The people in the areas where these crayfish live are subsistence rice-farmers, and crayfish harvesting is extremely important to them, both economically and as a source of protein. However, over-harvesting, combined with deforestation, has resulted in populations being lost.
This project will explore ways to increase the sustainability of crayfish exploitation. It will focus on social issues and will run alongside a scientific crayfish research programme. By involving local communities in every stages of the study it is hoped to arrive at an acceptable way of ensuring sustainable harvesting.
Crayfish are fast growing with relatively high rates of reproduction so changes in harvesting practice should be quickly seen in the population. Increasing the minimum size of individuals harvested and preventing harvesting during the breeding season could quickly benefit both the crayfish populations and the catches of local fishermen.
Project Update: March 2001 Our project now has a local name - Orana Tsara Tantana - which means 'well managed crayfish'. We have now recruited an extension officer, Lalaina Rakotoson, an environmental lawyer who has lived for ten years in the main town in the study area, and we have selected our study sites. We are planning to build a house for the project in Bevohajo, a village right on the boarder of Ranomafana National Park; about three hours walk from the road.
I will be based here with a student from the University of Tana, and another student from Fianarantsoa University will be based in Abodokimba, a village close to the town of Ranomafana where the National Parks Authority project attempting to cultivate crayfish is based. This student will be working very closely with this project. We are buying bikes and I will be able to regularly bicycle up to Abodokimba. Lalaina will be working with the villagers in both Bevohajo and Ambodokimba, and other villages where crayfish harvesting is important, to discuss the project and regularly feed information back to them and discuss how it could be applied.
Project Update: June 2001 Interviews have been carried out in 16 villages in the periphery of Ranomafana National Park and at "hotelys" and restaurants in the area (the main commercial sink for the crayfish).The interviews focused on the level of crayfish exploitation, its importance in the local economy and any perceived changes in the availability of crayfish. The survey revisited sites first assessed in 1990 just before the Park was established.
The team has held meetings with all these villages' elders and/or King to explain the objectives of the project and has done an interview on local radio, as well as school visits. A leaflet for local distribution is in production. Study sites have been selected for mark-recapture studies and for experimental crayfish culturing.
Project Update: October 2001 We had a really successful environmental activity day for the children in the village last week. The school teacher from the next village was very enthusiastic and we are planning a similar day to be held in the school now that term has begun.
2nd RSG Grant Awarded A 2nd RSG Grant has been awarded for this project.
Project Update: August 2002 The importance of crayfish to the economy of villages in the Ranomafana area varies widely with certain villages (particularly Vohiparara, Sahavondrona and Ambalavao-Tsararano) relying heavily on crayfish harvesting.
Other villages may contain certain individuals for whom crayfish harvesting is vitally important – these tend to be the poorer, often female headed households. Harvesting may have decreased in importance in the last 10 years since the park was established with fewer families carrying out crayfish harvesting commercially.
The most likely reason for this general decrease in reliance is the increase in alternative economic activities provided through the development of the area, particularly to those villages close to the town of Ranomafana. However, the markets for crayfish appear to have grown over the last 10 years and it is very difficult to estimate whether total number being taken has increase, decreased or stayed the same.
The key question is whether the current harvest is sustainable. The evidence obtained from interviews with villages and from the study in Vohiparara provided an interesting mix of rather contradictory evidence. A number of villages particularly those to whom crayfish harvesting is important, reported that there have been trends in availability and size of crayfish which indicate over-harvesting. However these same villages reported similar trends in the early 1990’s yet they continue to extract many 100’s of crayfish every week and travel times reported are not longer than those reported in the early 1990’s.
However one subject on which interviewees were in unanimous agreement was the decimation of crayfish stocks in the Reny’rano in Vohiparara. This was blamed on a combination of overharvesting, harvesting gravid females but overwhelmingly on the effects of introduced fish species fibata and bilakibasy.
The ecological evidence gathered so far is inconclusive, and further research is needed over the coming months.
Booster Grant Awarded A Booster Grant has been awarded for the continuation of this project.
Project Update: August 2005 Julia Jones looking for crayfish in a stream in Ranomafana, Madagascar.
The work has been going really well. We have extended our ecological work on the rare and less commonly harvested species which has been really interesting. We have also extended the geographical extent of our work, working in Bevoahazo and Vohiparara, Andemoka (a small slash and burn community deep in the forest who depend heavily on crayfish for subsistence use) and Sahavondrona (a village for who, like Vohiparara, selling crayfish to passersby on the road is a major part of their economy).
The population dynamics work continues, we now have 62 sites where we are carrying out mark and recapture on the most commonly harvested species (Oranbato, A. granulimanus) as well as sites for Orannsatria (A. betsiloensis) and Orapotika (A. crosneri). We have also started visiting Tanala villages to the east of the park where slash and burn has reduced the forest to tiny patches or completely removed it. The aim of this work is to demonstrate the simple fact that way beyond any effect of harvesting on crayfish, is the simple effect of habitat loss.
Our work strongly suggests, so far, that as long as there is forest there are crayfish (though heavy harvesting of course affects populations), however once the forest goes the crayfish go too. Rosa (a team member from Bevoahazo) and I have so far visited nine villages and had meetings with elders and young people to ask about what crayfish species are around, what species were present in the past, how populations may have changed and how important crayfish are to them. This work has been really interesting.
Many of these villages lost the forest from the surrounding hills (and the crayfish) in the last 10-20 years. Over and over again the link between crayfish and forest was spelt out to us by the elders. I asked if people missed the crayfish or if it made no difference as they were never an important economic resource (crayfish selling is 'fady' or taboo to most Tanala people). I was told 'we miss the Crayfish, Crayfish are very good food.’ Before you could always get loaka (sauce to eat with rice), if you were willing to collect but now there are no more'. The socio-economic work in Vohiparara and Sahavondrona is also going well. We have been working with the harvesters in these villages to map their use of the forest, seeing how far people are travelling, where they are collecting and how this overlaps with other communities.
This data is essential both to inform our ecological work on crayfish (we can only correctly understand our work on the population dynamics if we know the level of harvesting in these sites) and also to help understand the economic importance of crayfish and other forest products. Particularly in Vohiparara we have had wonderful cooperation with the harvesters for this work. People bring us their catches every day and take part in a small interview about where they went, for how long etc. The next day they tell us how much they earned from the honey/crayfish/frogs or whatever they had collected.
