Over the last five years or so as Freshwater Life Project has begun to implement our long term aim to assess the viability and initiate our program for re-introduction of Salaria fluviatilis to Cyprus, I’ve had a great deal of time to study and understand not only the implications of such a plan, but also about the behaviour and natural interactions of this lovable Blenny with its environment and particularly its role as a host for the larvae of the freshwater mussel Margaritifera auricularia.
Several years ago, it was by accident that I stumbled across the scientific publication by Yves Lignereux et al while searching for reports on the Amathus River in Cyprus. I came across their paper, which identified the presence of both M. auricularia (listed as the synonym cf. Pseudunio auricularia) and Unio cf. mancus, two freshwater mussels mostly likely consumed by ancient Cypriots around the time of the 4th-5th century at the ancient ruins of Amathus in the Limassol district; the interesting part about this finding was that Limassol district is also the location where the only known specimens of the Cyprus Blenny were found and so this naturally evoked a lot of questions in my mind.
On each of our 2015, 2017 and 2018 surveys of rivers in Limassol district, we have not been able to find evidence of either Salaria fluviatilis or Margaritifera auricularia, however since preserved specimens of Cypriot blennies do exist we cannot immediately rule out the possibility of Spengler’s mussel having existed once upon a time in Cyprus also.
Why would it be good to find Spengler’s Freshwater Mussel in Cyprus?
Since M. auricularia larvae, also known as glochidia, are dependant on their fish host to complete their life cycle, evidence of them in Cyprus rivers would provide irrefutable proof that the same habitats were formerly inhabited by the fish host; this would enable us to be sure that the re-introduction locations are the correct ones.
Loss of one means loss of both
Spengler’s freshwater mussel is one of the most threatened invertebrate species on Earth, formerly widespread across Europe it is now extinct in Belgium, Czech Republic, Denmark, Germany, Italy, Luxembourg, Netherlands, Portugal and the UK and only remains in just four locations (three in France and one in Spain). Of the remaining populations, all are in decline and the majority of the remaining individuals are all found within one population. None are particularly productive and this may be due to a lack of or low abundance of their natural hosts, which as well as Salaria fluviatilis includes Sturgeons in the Acipenser genus, but the list of threats to the species is truly remarkable and it is estimated that within 20-50 years the species will be eradicated from Earth altogether.
The Atlantic Sturgeon Acipenser sturio, arguably the main host for the glochidia of Margaritifera auricularia, was most recently recorded in the Mediterranean in 1991 when the last known individual from the region was fished and sold at a local market; similar fates have befallen the other members of the genus and as a direct result of this over-fishing we see the decline in Splenger’s freshwater mussel.
One extirpated species preventing the extinction of another?
With the absence of sturgeon in the Mediterranean and the possibility to re-introduce the freshwater Blenny to its former habitat in Cyprus, we are also presented with an opportunity to explore the idea that the introduction of Spengler’s freshwater mussel in Cyprus could prevent its untimely extinction. The idea of rewilding is still relatively new to the mainstream public and is already quite a controversial topic among conservationists, generating a great deal of debate and even criticism. It is also questionable as to whether this type of translocation would even constitute rewilding, since the evidence for the existence of the mussel on Cyprus is not certain other than its presence at the Amathus ruins, a human habitation to which it may have been transported as food.
A question of ethics
The issue of ethics around this sort of idea is important and we must aim to find either live or historical evidence of a freshwater mussel in Cypriot rivers or at very least find some degree of lost functionality that it may contribute before contemplating the prospect of introduction; at this stage we remain open and welcome to all professional consultancy/ experience and will continue our research with this idea in our consideration.
Learn more about our Freshwater Blenny Project