On Samothraki we researched waters. Invertebrates, water quality, riparian vegetation, wetlands, birds, marine life, conservation issues of all sorts, and fish.
One of our team's passions is studying fish in inland waters - any waters inland of the shoreline. Fishes are interesting because they require really special conditions and resources for survival in any inland waters; and conditions on small islands are usually difficult. On Mediterranean islands, stable inland water conditions are scarce. This includes coastal lagoons, stream mouths, and any isolated water behind the beach-fronts (all wetland types of course) and streams of course. On islands, stream freshwater fishes have a hard time surviving - they cannot live without freshwater, so even a single dessication event can render them extinct from an island. On the other hand, marine fishes that swim into inland waters and move upstream need barrier-free movement opportunities and these conditions are rare or often influenced by human water exploitation and various barriers (road-crossings, dams, weirs).
What we found in Samothraki
Working on seven of the most representative of the basins we electrofished and used seine fry nets to collect fishes. Of these only Agistro, Fonias, and the Agios Andreas Lagoon had fishes! (see map below). Although we sampled using the above equipment 10 sites (8 using electrofishing) only six sites had fish. I present initial findings here- some spp. are still not confirmed as to their exact identification.
We found the following taxa of fishes in Samothraki's inland waters:
-Three species of Mugillids (Grey-mullets): these marine fish breed in the sea but enter fresh and brackish waters to feed - they love to feed on algae and detritus so they probably contribute to the cleansing of eutrophic lower stream reaches.
-Two or three species of Blennies: in this case we caught wholly marine Blennies - species that enter fresh and brackish waters but probably reproduce in the sea only.
-Two species of Gobies: One unidentified species and one common marine sand goby have been collected.
-One species of Atherina (sand-smelt): Collected only at Fonias river mouth in large numbers; they commonly enter rivermouths and lagoons when there is an opening to the sea.
-One species of Eel (Anguilla anguilla): Collected only in two rivers, in fact the two which have a good connection to the sea and are mostly perennially flowing towards the sea (Fonias and Angistro). The eel is a globally endanged species, so this find lends special value to the inland waters of the island.
So the inland waters ichthyofauna of Samothraki have a total of at least 9 fish species. This is good, but still we have mysteries and unanswered questions. I was searching for a 'Dwarf Goby' called Knipowitschia caucasica, collected by Bulgarian researchers and published in the '60s; it was found nowhere.
Also, we found no true primary freshwater fishes. And this is remarkable since so much freshwater produced on the island flows to the sea - and at Fonias river for example we could have had a population of say River Blennies and even true primary freshwater fish. Our team searched hard - at one instant I had a hallucination that I saw a River Blenny at Fonias- it was probably a tadpole.
Για να δείτε το πλούσιο φωτογραφικό υλικό κι ολόκληρη την ανάρτηση πατήστε στον παρακάτω σύνδεσμο
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