Restoring coastal lagoons for the conservation of a critically endangered freshwater fish
Valencia toothcarp or samaruc (Valencia hispanica) is a small freshwater fish, endemic to Eastern Iberian coastal wetlands. It is restricted to a few small areas in Catalonia and Valencia, and is on the verge of extinction because of the degradation of its habitat and because of competition with Eastern mosquitofish (Gambusia holbrooki), a highly-competitive invasive fish.
Less than 10 wild populations remain, and they are geographically isolated from one another. Captive breeding projects are being carried out but protection of its habitat is inadequate.
This threatened species needs clean, lowland springs and does not tolerate high salinity levels. These springs have suffered intense degradation because of pollution, destruction and the introduction of non-native species.
Currently, the coastal lagoons at L’Ametlla de Mar (Baix Ebre) are a refuge for this species, due to the their unique ecological condition, and the scarce invasion by Eastern mosquitofish. In the area there are also populations of fartet (Aphanius iberus), another endemic Iberian toothcarp, which is also threatened, although its situation is not as critical as that of samaruc.
Coastal lagoons are considered habitats of priority interest by the European Union (*1150 Coastal Lagoons).
Coastal lagoons provide many valuable natural services, such as the buffering of sea–storms.
Many European coastal lagoons have either disappeared or are degraded. In this area, several shallow, clear lagoons exist, populated by aquatic macrophytes such as stoneworts (Chara hispida) and sago pondweed (Potamogeton pectinatus), and sorrounded by sedges, reeds and a rich dune vegetation. The lagoons have both a groundwater origin and a marine influence, and are located in the mouth of Mediterranean ramblas (temporary streams).
In this area, some coastal lagoons had disappeared due to natural and anthropogenic siltation. With the funding of Andrena, the organization Paisatges Vius designed the restoration of three previously existing lagoons, with the aim of recovering habitat for the samaruc.
Specific hydrogeological studies have guided all necessary diggings, in order to guarantee the hydrological functioning of the lagoons. The restored lagoons flooded naturally and immediately, due to their groundwater origin. Their environmental status is monitored using QAELS e2010 , an index of water quality assessment in Mediterranean wetlands based on crustacean and insect assemblages, and ECELS, an indicator for the general conservation status of the ecosystem, based on morphological aspects.
In order to establish new populations, samarucs (from captivity breeding) have been reintroduced in these lagoons, after an ecosystem assessment. Fishes are reintroduced during the mating and breeding season (late Spring).
- L’Estany Tort
Restoration of the original lagoon (january 2015), disappeared during the 70s. Reintroduction (may 2016) of samarucs from the breeding facilities at the Icthyological Centre in the Delta de l’Ebre Natural Park.
- Llacuna del Port de l’Estany
Restoration of the lagoon (may 2016), formerly disappeared due to siltation and disconnected from the sea by a road. Reintroduction (may 2017) of samarucs from the breeding facilities at the Icthyological Centre in the Delta de l’Ebre Natural Park.
- Llacuna de Torrent del Pi
Restoration of two more ponds in this system, increasing habitat size. Samarucs have colonized naturally this lagoon.
- Ichtyological Centre – Delta de L’Ebre Natural ParkEquipment and materials have been provided to support their toothcarp captive breeding program.