Acipenser naccarii (Adriatic Sturgeon) The Adriatic sturgeon is on the “critically endangered” list, and is indicated as being “possibly extinct,” as of a 2009 assessment (IUCN, 2017a). This is a species of sturgeon found exclusively in the Adriatic, both in fresh and sea waters. At its most robust, the species once had a range that extended as far south as Corfu, and as far inland along the Po River at its delta. It may even have been found in Spain, although evidence for this is inconclusive. The species was also located seasonally in the Venetian lagoon. There have been attempts to reintroduce the species to some areas, like Greece and also along the Po and other Italian rivers, but those efforts at population restoration have been unsuccessful. Since 1988, fish farming have successfully enabled the Adriatic sturgeon to spawn, but there is no evidence of wild spawning. The Adriatic sturgeon should be spawning in freshwater rivers.

The biggest threat to the Adriatic sturgeon is overfishing, and especially of catching the fish too young to reproduce. Another major threat has been the barriers to entry to its reproductive routes, such as dams along the Po River. This threat is being mitigated via the building of fish passages to allow the sturgeon to swim past...

The Allee effect, habitat competition, and water pollution are also threats.
Amazilia boucardi (Mangrove Hummingbird)

The mangrove hummingbird is described as being medium-sized for the species, and characterized by its green and bronze-green coloring. In fact, male and female have similar coloring with the female having more green spotting on the throat than the male, which has a turquoise-green throat. It is listed as being “endangered.” The mangrove hummingbird is endemic to Costa Rica, in a very narrow range of the Pacific coast “from the head of Golfo de Nicoya to Golfo Dulce,” (IUCN, 2017b). It has “patchy distribution” throughout the coastal mangrove areas, with current population estimates at about 2,150-4,150 mature individuals (IUCN, 2017b). Its preferred food source is the flower of the Pacific mangrove Pelliciera rhizophorae, but the species is not found in all areas along the coast with this type of mangrove. Also, the mangrove hummingbird has been spotted in adjacent areas that do not have this mangrove species. They nest between October and February.

The most significant threat to the mangrove hummingbird is habitat destruction, caused by human activities like the construction of commercial…