A threatened dwarf among fishes could threaten other species

New study on Adriatic dwarf goby distributions gives insights on its invasive potential

Scientists recently published a study in Marine Biodiversity on the distribution of a goby fish, named Knipowitschia panizzae also known as the Adriatic dwarf goby. Although a dwarf among gobies, K. panizzae is giving scientist a headache. Knipowitschia panizzae is threatened by itself. But the expansion of its distribution could threat the conservation of other threatened species. The findings of the newly published study by Spinelli et al. 2017 show that this threatened goby fish has invasive potential in vulnerable transitional water habitats.

Image: Scientists in the Field monitoring the Fauna and Flora of Capo Peloro Lagoon / Source: provided by Dr. Andrea Spinelli

Where do gobies live and why are they important?

Gobies are worldwide distributed and one of the largest fish families comprising more than 2,000 species. One can find them in tropical and temperate near-shore marine, brackish and freshwater environments. Usually, gobies are relatively small, typically less than 10 cm (3.9 in) in length and in general of minor impatience to food as humans. Nevertheless, one should take into account that they are of great significance as prey species for commercially important fish.

What is threatening the Adriatic dwarf goby?

The Adriatic dwarf goby is native to the Mediterranean Sea. Specifically, the distribution of the Adriatic dwarf goby is limited to the Adriatic and Ionian Seas, where it prefers fresh and brackish waters with plentiful vegetation. Unfortunately, “it is a threatened species and it could be extinct in habitats within its natural range of distribution due to habitat degradation and destruction” states the leading author Dr. Andrea Spinelli from the University of Messina (UM) and specifically from the Department of Chemical, Biological, Pharmaceutical and Environmental Sciences in Messina, Italy. “The anthropogenic pressure is one of the most important processes, which could modify the distribution of the Adriatic dwarf goby. Therefore, the species has been proclaimed to be endangered and protected in Italy and Croatia and it is also listed in Appendix III of the Bern Convention and in Annex II of the European Union Habitat Directive.”

Image: The Adriatic dwarf goby Knipowitschia panizzae / Source: provided by Dr. Andrea Spinelli

Where did the Adriatic dwarf goby invade?

In the framework of the program of the Provincia Regionale di Messina, entitled “Settlement dynamics and colonization of allochthonous assemblages in the Capo Peloro Lagoon” scientists directed by Prof. Giacobbe (UM) are monitoring the Capo Peloro Lagoon since 2010.

Already in the past, the scientists were able to announce the first record of another goby, the large-headed goby, Millerigobius Macrocephalus in the Lagoon. Now in 2015, “during our monthly monitoring, K. panizzae we first observed in the Ganzirri canal” says Dr. Andrea Spinelli. The Ganzirri canal is part of Capo Peloro Lagoon that host two lakes, the Ganzirri and Faro lake. The whole lagoon receives significant marine inflows through the canal. Therefore, the canal is a gateway for introducing invasive species. “Exactly there in the canal, we found all 12 counted K. panizzae species. They were near the artificial rocky banks, lying on the bottom or swimming approximately 50 cm above the canal bed” describes Dr. Andrea Spinelli from UM.

Image: Capo Peloro Lagoon – Area of investigation / Source: provided by Dr. Andrea Spinelli

What or who introduced the Adriatic dwarf goby?

“The spreading of the species has been suggested to be of anthropogenic origin,” underlines Dr. Andrea Spinelli and adds that “such spreading, is in accordance with the already proved by other scientists introduction of flora and other fauna into Faro lake.” As the Adriatic dwarf goby is rapidly growing and is opportunistic generalist predator, could easily become invasive species in fragile ecosystems such as the Capo Peloro Lagoon.

Why is the threatening the Capo Peloro Lagoon?

The “Capo Peloro Lagoon” is a zone of special protection and a site of community interest. It has been listed as Natura site (ITA 030008). Both lakes that the Capo Peloro Lagoon hosts are subjected to high anthropogenic pressure. To be able to measure the impacts on the marine ecosystem scientists need to know the actual habitat and its inhabitants. “Unfortunately, the faunistic or floristic inventory of this ecosystem is still scare,” says Dr. Andrea Spinelli from UM “but through the program of the Provincia Regionale di Messina we can now monthly monitor this fragile ecosystem”.

Based on the recent findings of Dr. Andrea Spinelli and his colleagues (Spinelli et al. 2017), they suggest that “the population dynamics of K. panizzae and its influence on the ecosystem of the Capo Peloro Lagoon should be monitored. Based on these data the relation to the possible further spreading of K. panizzae along Mediterranean lagoons could be then further investigated”. The authors’ goal is to inform citizens and scientists that could contribute with their observations to the investigation of other introduced species and specifically to describe the current state of the Adriatic dwarf goby and other invasive species.