*7.2. Gobiiformes, Gobionellidae*

*K. panizzae* and *N. canestrinii* distribution is more limited than that of *A. fasciatus*; however, where present, they show important density, demonstrating an exclusive relationship with lagoon morphology. *K. panizzae* partially provides similar information as *A. fasciatus* does for saltmarsh systems, but it is also sensitive to alteration of mudflats (sensu Wolanski and Elliott [111]), where males usually prepare the nests. Therefore, the creation of infrastructures (such as navigable canals and water pipe digging) or their maintenance and, in general, the use of dredging systems represents a serious threat for the local population, ending in the destruction of breeding sites. Males of both species need hard structures and cavities to build their nest, such as shells or other artificial structures. This means that the substrate of their breeding habitats should be structurally complex.

Depending on the habitat structure, the literature demonstrates that the population density of *K. panizzae* can vary by even up to two orders of magnitude. Approximately, it can be supposed that a population with an annual density below 100 ind/100 m<sup>2</sup> should be monitored with particular care.

Despite being able to tolerate high eutrophicated systems [67] and suffering from the alteration and fragmentation of native habitats, due to the loss of typically lagoon morphologies as in the case of *A. fasciatus* and *K. panizzae*, *N. canestrinii* is particularly sensitive to salinity increase, its optimal salinity values ranging from 2 to 20 and never exceeding 30 [87]. Human-regulation of water exchanges is frequent in Mediterranean costal lagoons to meet the need for numerous anthropogenic activities, such as navigation and fishing and aquaculture, and to maintain the functioning of the ecosystem [122]. Modifying communication with the sea and dredging canals may lead to significant changes in retention time [123] and salinity values [122]. Moreover, the ongoing climate changes and the future sea-level rise can accentuate these processes, increase eutrophication and accelerate the erosion rate of wetlands [5,124]. Although the species seems to not be affected by high eutrophication levels, the salinity rise and the saltmarsh degradation remain a serious threat. In light of these considerations, the decrease of *N. canestrinii* populations could be a marker of environmental processes leading to higher salinity and a higher sea level, indicating a direction of change in coastal lagoons towards marine environments.

### *7.3. Conservation Management Issues*

Consulting the European Union database and the literature:

	- a. data collection is compulsory, and in the case of Natura 2000, started in the mid-1990s and for all Member States, allowing the assessment of long-term trends on a large spatial scale;
	- b. data are comparable;
	- c. the access to funding can be facilitated.
