*4.2. Conservation Status*

*K. panizzae* is not a species considered to be at risk (for IUCN it is least concern and the conservation status is favourable) and can survive, as in the example of Comacchio, even in the case of high eutrophication, but the destruction of original habitats, mainly from a morphological point of view, can result in local population decline. In the Venice lagoon, *K. panizzae* was found to considerably prefer canals inside the salt marshes, compared to the open lagoon complex [80]. Its density, in fact, can vary significantly on both spatial and temporal scales: the annual mean in a saltmarsh creek was found to be 1374 ± 3167 ind/ha, while in a saltmarsh close to man-regulated canals it was 58 ± 80 ind/ha; during summer, in the saltmarsh creek, up to 14,000 ind/ha can be collected [69], while in autumn density can be 780 ± 1402 ind/ha [80]. The preference for more sheltered areas and possibly with macroalgal cover may depend, also, on the potential greater availability of bivalve molluscs of the genus *Cerastoderma*, whose shells are chosen as nest by males [39]. As a result, erosion and alteration of the natural habitat, with the decline or disappearance of the structures of salt marshes can compromise the population vitality [69].

*K. panizzae* was reported in 34 Natura 2000 sites, 25 of whose are coastal lagoons (Table 3) distributed along the Adriatic coast both on Italian and Balkan side [81,82]. However, recent phylogenetic studies, based on mitochondrial DNA analysis, have shown that *K. mrakovcici*, *K. radovici* and *K. panizzae* are not distinct species and are all *K. panizzae* [12], so the distribution range of the species should be reconsidered. The Adriatic and Ionian seas are the centre of diversity for sand gobies, with a total of 17 species belonging to five genera, including *Knipowitschia* and *Ninnigobius* [12]. The wide distribution of *K. panizzae* and the high ability to survive in extreme conditions allows us to suppose a good intraspecific genetic diversity, favoured also by the panmictic behaviour and by the presence of a free postlarval stage, favouring specimen dispersion with tide currents. However, there is a lack of specific studies comparing the genetic diversity among populations from di fferent regions.
