PROJECT DESCRIPTION
BACKGROUND
The European sturgeon (Acipenser sturio) is one of five priority fish species listed in Annex II of the Habitats Directive. Once a very wide ranging species from the North and (Eastern) north Atlantic and Mediterranean coast of Europe and the Black Sea, the world population has been reduced to one last declining population in the Garonne catchment - Gironde estuary/ Garonne and Dordogne rivers - which harbours no more than 500 to 2 000 individuals. These immature fish all come from the last recorded breeding cycle in 1988 and probably constitute the best chance of survival for the sturgeon. Despite total protection accorded to the species since 1982, the population continues to decline dramatically because of the degradation and inaccessibility of spawning sites; water pollution, and accidental fishing (by-catch).
The LIFE project formed part of a larger long term national programme for the preservation of the sturgeon. This was necessary as the particularities of the species (average reproductive age is about 25 years) meant that it would be sometime before any positive results would appear. The project would also contribute to the improvement of water quality in the aquatic environment and to the conservation of most other migratory fish species. Eventually the economic benefits of this species could also be envisaged such as the production of caviar.
OBJECTIVES
Working from a sound scientific base, this project had two principal objectives: urgent actions for the rehabilitation of the breeding and feeding sites of the European sturgeon (Acipenser sturio), and the perfection of a captive breeding technique using a core genetic stock to produce juveniles for reintroduction.
In addition, information would be collected on the distribution and levels of by-catch in the estuary and coastal waters as well as an information and education campaign designed to gain the support for this flagship species amongst the general public.
The specific measures planned to achieve these objectives were:
1. To collect fish from the wild to establish a captive breeding stock for the artificial reproduction of young fish (alevins). A proportion of the alevins reared would be released into the wild to restock the remnant wild population, with the remainder kept for rearing in captivity to the juvenile stage.
2. To identify and determine the quality of suitable natural spawning sites still accessible to breeding sturgeon on the Dordogne and Garonne rivers, and the extent and effectiveness of current statutory protection for these sites.
3. To monitor the remaining wild European sturgeon population to determine its migratory movements and distribution in the Gironde estuary and open sea beyond, and the levels of by-catch.
4. To raise awareness of the European sturgeon’s plight amongst fishermen and the general public to generate support and cooperation for conservation measures. .
RESULTS
Although there still remained a lot to be done to safeguard the future of European sturgeon Acipenser sturio, the LIFE project played a major role in collecting the scientific information needed to advance and direct the measures necessary for its long term survival. As well as achieving all of the project’s specific objectives, LIFE was also instrumental in establishing a close working relationship between all the stakeholders (scientists, technicians, elected representatives, fishermen and NGOs) which would be essential for the continuation and realisation of future conservation actions.
Specific achievements for the four key objectives are:
1. To establish a captive breeding population.
The capture of a sexually mature male and female in 1995 resulted in the artificial reproduction of 23 000 young fish (alevins): 9 000 were released into the wild and 240 fish were reared in captivity to the juvenile stage from the remainder. A lot of practical knowledge on the conditions required to rear European sturgeon in captivity was gained from this operation. This would be vital for the success of future captive rearing as sturgeon are very long lived and do not reproduce until 10-15 years old.
2. Quality and protection of remaining spawning sites.
From an initial 31 sites identified, 23 were considered to be still suitable as spawning sites (9 on the Dordogne and 14 on the Garonne), which was estimated to be sufficient for the needs of the current breeding population. 22 of the 23 potential spawning sites were protected by regional habitat protection orders (APPBs), but despite this some were still damaged.
3. Monitoring movement of the remaining wild population and by-catch.
Thanks to a close working relationship between fisherman and research scientists, a lot more is now known about the sturgeons distribution within the Gironde estuary (90% of juveniles in just four sectors) and at sea (85% in French waters), as well as its migratory habits and the fishing practices to which sturgeon’s are most vulnerable and therefore detrimental to its future survival. These results will help identify zones where modifying practices or restricting fishing should greatly reduce losses due to by-catch, a major cause of the current population decline.
4. Raising awareness.
A communications strategy (posters, brochures, stickers) targeted professional fishermen and was successful in modifying their attitude and response whenever they accidentally caught a sturgeon. The wider public was targeted through a travelling exhibition and feature articles in magazines.Although there still remained a lot to be done to safeguard the future of European sturgeon Acipenser sturio, the LIFE project played a major role in collecting the scientific information needed to advance and direct the measures necessary for its long term survival. As well as achieving all of the project’s specific objectives, LIFE was also instrumental in establishing a close working relationship between all the stakeholders (scientists, technicians, elected representatives, fishermen and NGOs) which would be essential for the continuation and realisation of future conservation actions.
Specific achievements for the four key objectives are:
1. To establish a captive breeding population.
The capture of a sexually mature male and female in 1995 resulted in the artificial reproduction of 23 000 young fish (alevins): 9 000 were released into the wild and 240 fish were reared in captivity to the juvenile stage from the remainder. A lot of practical knowledge on the conditions required to rear European sturgeon in captivity was gained from this operation. This would be vital for the success of future captive rearing as sturgeon are very long lived and do not reproduce until 10-15 years old.
2. Quality and protection of remaining spawning sites.
From an initial 31 sites identified, 23 were considered to be still suitable as spawning sites (9 on the Dordogne and 14 on the Garonne), which was estimated to be sufficient for the needs of the current breeding population. 22 of the 23 potential spawning sites were protected by regional habitat protection orders (APPBs), but despite this some were still damaged.
3. Monitoring movement of the remaining wild population and by-catch.
Thanks to a close working relationship between fisherman and research scientists, a lot more is now known about the sturgeons distribution within the Gironde estuary (90% of juveniles in just four sectors) and at sea (85% in French waters), as well as its migratory habits and the fishing practices to which sturgeon’s are most vulnerable and therefore detrimental to its future survival. These results will help identify zones where modifying practices or restricting fishing should greatly reduce losses due to by-catch, a major cause of the current population decline.
4. Raising awareness.
A communications strategy (posters, brochures, stickers) targeted professional fishermen and was successful in modifying their attitude and response whenever they accidentally caught a sturgeon. The wider public was targeted through a travelling exhibition and feature articles in magazines.