How many species of freshwater fish in Greece: A new book!

New checklist  May 2015

How many species of freshwater fishes in Greece?

The ichthyologists at IMBRIW- HCMR have for years worked on answering this question. Its not easy. And it is important.

We're talking about "species" - a supposedly solid taxonomic unit.

well...it is not that solid or easily defined!

The concept of species has evolved. And now, following the Phylogenetic Species Concept (contra the Biological Species Concept) a major revision of species entities has taken place. In Europe the 'revolution' crash-hit us when Maurice Kottelat and Jörg Freyhof published their "Handbook of European Freshwater Fish" in the summer of 2007. This book provided a kind of whole-scale validation for many new species of inland fishes in Europe ("new" chars, whitefish, salmons, trout). All of a sudden we had many  new species, many of them formally and/or formerly known as subspecies just a few months before. Following the new 'evolutionary' approach to species definition, the notion of sub-species is dead. So even if our country is already famously rich in fish species - what do you do when many of the former entities are split-up with new shiny names?

Now how many in Greece?

In April 2015 we published our annotated list and conservatively defined the number at 160 species firmly following our colleagues Maurice and Jörg. Our new checklist booklet is not one to purport brevity - so if you do read it you will see that we do point to the controversies the new species concept has created.

Now how did we keep track?

This is not easy for the following reasons:

a) Several species groups are poorly studied and need to be re-assessed; studies are in the pipeline that will certainly increase the species number, especially where former subspecies existed. So we expect to see at least another 10 species entities arise within the decade - this is a conservative estimate but we have firm evidence that new species units will be described in the genera of Squalius, Eudontomyzon, Alburnoides, Knipowitschia, Barbatula, Gobio, Rutilus and maybe others!

b) Some species are not only created but may be "lumped" into others and re-assessed not as species but as local population units at best. This may be possible but I predict not many such changes will occur. There are some fish that may fall into this category (one or to Cobitid loaches I believe). Also the new taxonomic work may show that species that were to exist in this country are now proven not to exist since the Greek populations belong to other species. (We did "lose" two species in this way during the last list revision - Salmo dentex and Barbus rebeli where recently deleted from the Greek fish list).

c) Aliens species.They come and "go". Now we confirm 23 species are aliens (the last list had 29!) We have proved that several species where never really established and we have no evidence of several species that were included on Greece former ichthyofaunal list. This issue needs careful monitoring. 

d) The evidence of many Mediterranean marine transient fishes in fresh waters is growing; surely the line is not black-and-white. Already many fish that breed solely in marine waters are included in the freshwater list (grey-mullets and eel for example). And including these migratory fishes is commonplace in most inland faunal country assessments worldwide. Some marine fish are common, widespread and often found in pure freshwater conditions not just the brackish river mouth extremes (a.k.a. transitional waters). Our 2007 list estimate guesstimated that at least 55 'marine' species are frequent migrants or transients into transitional waters (river-mouths, coastal marshes etc). So we need to work on criteria to include the most frequent - pervasive marine transients in the inland waters list. I wager this will help the inland waters list increase by about another dozen fishes within the decade. 

So its at 160 and 47 are exclusive endemics to the Territory of Hellas. 

Where do we go from here?

Web-based ichthyofaunal tracking tool: Fishlist.gr

We are now building a special website that will include all photos/drawings of fishes in Greek inland waters. Plus added information on identification, distribution and conservation and their common names (we especially worked hard to help standardize common names). The web-based tool will also be in Ελληνικά. The first phase of this project will be on air after June 2016. So please keep watching IMBRIW at: http://imbriw.hcmr.gr/en/

The fish checklist booklet is available free-of-charge as a PDF download at http://imbriw.hcmr.gr/en/wp-content/uploads/2015/05/FINAL_MARCH_2015_FreshwaterFishlist-1.pdf and hardcopies may be ordered for libraries and scientific institutions from info@fishlist.gr

The book can also be ordered free-of-charge, if one writes a polite note to us at: 

c/o Mrs. Sofia Giakoumi,
HELLENIC CENTRE FOR MARINE RESEARCH - HCMR
Institute of Marine Biological Sciences and Inland Waters - IMBRIW
46,7 km Athens-Sounio, Anavissos, Attiki, GR-19013 Greece
Tel.: +30 22910 76393

The Aoos river near the Greek-Albanian border: Several new species recently became named and valid as such in this river just in the last 10 years. Still we have doubts about the valid names of at least couple of species (Squalius, Chondrostoma). Research is needed to clear up the taxonomy in this globally important ichthyofaunal area.

Without genetic work it is no longer possible to identify most trout species in Greece. There are five species of native trout. However, unfortunately these fishes are being genetically polluted by mixing through unregulated stocking practices. Stocked fish sometimes show deformities they made in hatchery enclosures (see dorsal fin on this fish from the upper Acheloos - caught at near Anthousa Village in 2007).

The Endengered Beotian Riffle Dace (Τelestes beoticus). This species has a very restricted distribution and seems to require good flowing waters - it may be rarer than we think. More research is urgently needed. (Photo near Livadia in the Kiffisos river catchment).

One of the most enigmatic fishes in this part of the world is the anadromous Atlantic Sea Lamprey. This one was caught by a spearfisher on Kefallonia. We have anectodal evidence for the fish in the Louros river, it may spawn elsewhere. It si a protected species and very rare in Greece. (photo from Tassa Gouzi (Τάσσα Γρουζή) from Kefalonia, downloaded from: http://pronnoi.blogspot.gr/2013/04/t.html). The find was published  in https://www.researchgate.net/publication/266030219_First_confirmed_record_of_Petromyzon_marinus_Linnaeus_1758_from_west_Greece

Common Carp in Greece...does the wild form exist? Probably not,  as our book states. Perhaps the wild stock should be considered extirpated. This photo from the Aliakmon River near Polyphyto reservoir shows a wild-like form of Carp. It did look a lot like the sazan type of the Danube to my experienced friend, Uwe Dussling (Photo by Alkis Economou).

Manos Sperelakis, Yannis Kapakos and Graphics Artist and Publisher, Aris Vidalis (R) with a pallet of Books at HCMR.

The drawings in the book are by our Italian colleague Roberta Barbieri who has been part of the HCMR team since the late 1980s. This is certainly one of the most important aspects of the book - not just decorative. (Catfish).

Finally some notes about HCMR's new book:

The new annotated checklist of Greece’s freshwater fishes was  published in April 2015, the latest such booklet since Economidis’s 1991 seminal popularized checklist. The 134 page book features a brief introduction and carefully coded annotated accounts for 160 species. Particular emphasis is given to the interpretation of recent name changes and taxonomic validity. The book stresses the conservation value of Greece’s freshwater fishes; 47 taxa are noted as exclusively endemic to Greece and there are still important knowledge gaps on the taxonomy of several taxa. Many species are threatened at a global scale and there are fears that some may already be close to extinction; a notable example being the Vistonis Shad (Alosa vistonica) endemic to Lake Vistonis, a large wetland system which has suffered from extreme water abstraction, salinization and pollution. This book’s compilation is based on a group effort; it is authored by 12 members of HCMR and is illustrated with fine line drawings made by Roberta Barbieri. Professor Konstantinos I. Stergiou provides a forward and lends support to initiatives that strive to scientifically compile and maintain national fish checklists.

-------------------------------------------------------------------------------------------------------------------------

And finally some thanks to all who helped so much.

Firstly there are many poeple who keep reminding us to dessemintate our work to the public - to popularize our work. These people send us photos and location information about fishes in Greece - and this book is really inspired by them.

I want to thank some people for really working carefully on this book. First of all Alkis Economou who passed through the book with fine-toothed comb so many times. The rest of the team worked extremely hard - it's hard to explain how hard it is not making mistakes in a checklist! Evan simple things like the fishes totally lenghs need to be checked and re-checked. The English was edited my good cousin in Minnesota, Emily Green. And finaly Dimitra Bobori, Jörg Freyhof and Nicolas Bailly did an excellent job of reviewing and finding even more uncertainties and details. I especially want to thank Jörg Freyhof - who is an expert naturalist and knows about lists. And finally our friend Aris Vidalis for publishing with patience.  

Intermittent vs Perennial streams in the Mediterranean

A very rare near-pristine perennial stream in mid June in Western Turkey (Alabayir Village, near Cine on the Cine river catchment); A single species of fish is present. Note that few deciduous trees and shrubs are in the riparian zone. 

Stream flow intermittency: an elusive concept

Most people don't consider the one-and-most important attribute defining stream ecosystems: the states of intermittent versus perennial flow regime. I think the Australians call this issue "ephemerality of flow". Its a big topic in Med and semi-arid climates. Low or no flow periods during summer are typical in the Mediterranean climate regions; they are a key ecological limiting factor in these ecosystems. There seems to be a threshold and break point. After regular dessication for a few months these river systems are different: intermittent. They are therefore considered temporary rivers - a wide variety of temporary rivers exist.

Prior modification by humans, many intermittent or ephemerally flowing streams where in fact perennial! Very few people know about this (or seem to care). So what we see a lot of today are "artificially intermittent streams" due to anthropogenic pressures (i.e. over-pumping of aquifers, tapped springs, over-abstraction of surface waters, dams etc).

Streams are varied, many types exist in the Med.
Many small catchments are really desiccated naturally by local climatic conditions: Lengthy drying periods that occur naturally and make rivers bone-dry for a long time (over 4 months, for example). These are naturally intermittent. When there is no groundwater feeding, no wet refugia for wholly aquatic life we have very few wholly aquatic biota that can adapt. These naturally intermittent streams are interesting, full of wonder and semi-aquatic life but they are different from perennial systems: fewer hygrophilous deciduous trees, fewer and hardier fishes, different plant communities, different species of water bugs; many terrestrial species living withing the river-bed.

An artificially intermittent stream in Western Turkey, near Karpuzlu; here most of the water is pumped away for agriculture and large sections are dry for a for a few months. Summer 2014.

A small intermittent stream in Eastern Central Greece, near Lamia in early June. One species of fish, Sperchios Barbel present in tiny pools. The fish migrate up and down when the stream floods in winter-spring. Summer 2014.

The above stream 4 km downstream of the above site; near Lamia, Greece. Bone-dry by early June; no fish. Is it naturally or artificially intermittent? The big trees are Oriental Planes good indicators that there is ground water. There may be a wet hyprhoeic zone beneath the stream bed. Summer 2014.

The Xeropotamos river on Samothraki Island - it is a naturally intermittent stream (now totally intermittent due to increased water diversions for agriculture). The river bed is wide and a fascinating rocky habitat for local terrestrial biota. This photo is from late July. Note the near-lack of deciduous trees on the riparian. Summer 2014.

The Erassinos stream of Attika Greece (near Vravrona outside of Athens) in February 2014. This stretch is an artificially intermittent part with no fishes and reduced riparian vegetation. Upstream - about 3 km - are the rivers springs which maintain water and fishes year-round.

Fishing in a small intermittent stream in Southeast Cyprus, the Oroklini stream just south of the National Highway between Larnaka and Pyla. The stream is now artificially perennial due to the increased waters from sprawl in its small catchment! Mosquitofish and eels exist at this section (just before Oroklini Lake).Winter 2012.

Definitions for education's sake:

Perennial Stream – A well-defined channel that contains water year-round during a year of normal rainfall. Aquatic environment of river bed located below the water table for most of the year. Groundwater is the primary source of water for a perennial stream, but it also carries storm-water runoff. The flow may be heavily supplemented by storm-water runoff. Hydrological and physical characteristics commonly associated with the continuous conveyance of water.

Intermittent Stream – A well-defined channel that contains water for only part of the year, typically during winter and spring when the aquatic bed is below the water table. Water is absent - in a "bone-dry" conditions for at least three months for a considerable stretch of the stream (in a normal year). Entire river sections (tens of kilometers normally are dry in summer). Usually the riparian vegetation and aquatic vegetation are different in a similar stream with Perennial character. An intermittent stream often lacks the biological and hydrological characteristics commonly associated with the perennial conveyance of water. 

Ephemeral Stream – Ephemeral stream means a feature that carries only storm-water in direct response to precipitation with water flowing only during and shortly after major precipitation events. An ephemeral stream may or may not have a well-defined channel, the aquatic bed is always above the water table, and storm-water runoff is the primary source of water. An ephemeral stream  lacks the biological, hydrological, and physical characteristics commonly associated with the perennial or intermittent conveyance of water. In the Mediterranean deciduous trees are usually absent on ephemeral stream riparian zones.

I'll keep you posted about this topic in the near future.

• Check this link for a general development from the states:

Intermittent vs Perrenial Stream Bioassessment Arizona USA

• For a recent European approach developed within the MIRAGE project which HCMR also took part in please see:

A novel approach to analysing the regimes of temporary streams in relation to their controls on the composition and structure of aquatic biota

• Another integrated presentation of classification approaches again from the MIRAGE project which HCMR also took part is:

THE_MIRAGE_TOOLBOX_AN_INTEGRATED_ASSESSMENT_TOOL_FOR_TEMPORARY_STREAMS