Experimental site of the Lapitxuri

Scientific & technical context:

INRAE built the experimental spawning channel of Lapitxuri in 1980 as part of the "Salmon" plan (state/regional funding and ministry). The objective was to study the optimal conditions for the development of Atlantic salmon in a semi-natural environment and to define the scientific basis for the production of restocking juveniles, with a view to technology transfer. Since then, many scientific programs have relied on the site, particularly original and unique in Europe, to carry out experiments in ecology and behavior study (growth, dispersal, reproduction,...).

Description of the facilities:

The channel is built at the head of the Nivelle basin, in the municipality of Aïnhoa. The absence of intensive agricultural and human activity ensures the good physico-chemical quality of water and the absence of pollutant. Average temperatures range between 4 and 20°C over the year. The site’s breeding facility is recognized as free from VHS/IHN (approval number 64330056) and is monitored annually by the Aquitaine GDSA and DSV 64. The 4 tools present on the site are:

•  The spawning channel : fed by a diversion from Lapitxuri stream, it has a slope of 2%, measures 130 m and consists of a succession of 13 reaches (10m x 2.8m). The inflow is adjustable from 50 to 150 l.s-1 and an automated pumping/recirculation system allows the water to rise upstream of the channel in order to compensate for the low flows of the derived stream. The granulometry (10 to 80mm) and physical parameters (water height, surface and connectivity of the reaches, etc.) can be adjusted. Anti-bird nets avoid the risk of predation on fish. One of the originalities of the channel lies in the possibility to study behaviors thanks to underwater observation chambers and video equipment. During the night period, airborne infrared lighting allows certain behavioral monitoring.

• 10m troughs : 8 troughs (10m x 0.5m, depth: 0.25 m) allow experiments on young stages (salmonids). Different sets of grids or pitfalls are adaptable. Shading nets limit water warming, algae development and avian predation. They are supplied with filtered water at 15 μm for a maximum flow rate of 52 l.s-1 and are equipped with a passive safety system eliminating the risk of water supply interruption due to power cuts.

•  The incubation laboratory : it allows the incubation and monitoring of small batches of eggs or fry. It is equipped with two Heath-type cabinets (capacity of 160,000 eggs), 6 incubator troughs and 6 bins of 60L. It is supplied with 15 μm filtered water to avoid the risks of clogging the shelves in case of flood.

•  The breeding platform : it is equipped with 16 basins of Swedish type of 4 m²  and 8 basins of 1 m² . It allows the stabling of fish and possibly the rearing of juveniles in connection with experiments on site or off-site (natural environment, technical platform, ...).

Contact : Jean-Christophe Aymes

Location