The biology and ecology of Valencia letourneuxi Sauvage 1880 (Valenciidae) - Prospects for conservation

Data are provided on the distribution, abundance, early development and biology of the endangered Greek endemic species Valencia letourneuxi Sauvage 1880, along with a record of its occurrence at new localities. V. letourneuxi is a small-bodied and short-lived insectivorous species, exhibiting cryptic colouration and sexual dimorphism. It matures in the first year of life, reproduces serially in late spring and summer, and deposits spherical eggs, around 2 mm, on aquatic plants. Most morphometric characters show size-specific trends, which complicate comparisons among populations or with other species. Of specific systematic importance is the relative position of the anal and dorsal fins, which remains almost unaltered throughout development, and allows safe distinction from A. fasciatus. The species was found mostly in deep areas with clean and slow running water, usually associated with freshwater springs. Rich submerged vegetation is the prominent ecological feature of all sites in which the species was found. Using as criteria of rarity the limited geographic distribution, the confinement of the species in few localities of each aquatic system and the low local densities, V. letourneuxi can be characterised as a "restricted and locally rare species". The restricted distribution, coupled with the narrow ecological requirements, makes the species vulnerable to extinction. Its disappearance from at least four aquatic systems and the serious population decline in a number of other systems seems to be connected with habitat loss or degradation caused by human activities. The prospects of conservation are discussed

Portraying fisheries and ecological status of a Mediterranean lake

Background. Gaps of knowledge in lentic systems and discrepancies in official fishery statistics biased fisheries state and inhibits the development of conservation strategies. For that reason the integration of conventional (official data from fisheries landings) and unconventional (fishermen knowledge) sources of data, accompanied with the use of historical archives will outline the framework of the monitoring of freshwater resources.The presently reported study integrated local ecological knowledge of fishers, historical data, field surveys and scientific data to present better management options for a Mediterranean lentic system (Volvi Lake, northern Greece). Materials and methods. On-the-spot interviews were conducted with the professional fishers of Volvi Lake (northern Greece) in parallel with field surveys of environmental parameters during 2014–2015 and complemented with archival freshwater-related information. Results. The results of the presently reported study point to commercial fisheries as a declining activity, with little scope for a future, due to internal and external threats. This diagnostic can probably be generalized beyond the case study to other freshwater ecosystems in Europe, where decreasing fisheries productivity due to overfishing, habitat loss, and pollution, coupled with low economic productivity has led to an increased marginalisation of freshwater fisheries. Conclusion. The reported difficulties of freshwater fisheries could be bypassed through creation of fishers’ typology regarding their dependence on fisheries. Upgrading the methodological approach followed by the official reporting system in freshwaters might also facilitate the fulfilment of the requirements of the EU Water Framework Directive