The Mornos Goby - A new species restricted to the Mornos Delta, Greece

Economidichthys mornosensis / Mornos Goby / Μορνογωβιός (photo: S. Zogaris)

A new species of Goby!

Inland ichthyofaunas in Greece are more than just species lists; they are living indicators of  biogeographic history. The have guided us in the study of describing evolutionary regional units - ecoregions. Their distribution and evolutionary relationships help us reconstruct geological events that shaped aquatic biota at various scales in time and space.

Yet despite decades of research, some small fish species remain taxonomically unresolved. Among them are the tiny freshwater gobies: small, morphologically subtle creatures with disproportionate biogeographic significance. They are good biogeographic indicators because they ''stay put'' - the don't migrate or disperse easily. One of them turned out to be a new species - we discribed it, published just a few days ago, we are calling it Economidichthys mornosensis - the Mornos Goby...endemic to the Mornos Delta!

The Suspicion: Something Didn’t Fit

In the 1990s, Professor P.S. Economidis (1934-2022) noted that a very small goby lived in the Mornos Delta - a delta in the huge and deep Gulf of Corinth. It resembled a species of the genus Knipowitschia, but he expressed doubts about this. Years later, genetic analyses we conducted with our Belgian partner Maarten P.M. Vanhove confirmed that the Mornos goby population was clearly distinct from known species. It does not belong to the Knipowitschia, but to the gobies of the genus Economidichthys — a group of small endemic fish of western Greece named in honor of Economidis. For many years, our fish team at HCMR, often collaborating with co-workers from abroad, has worked on these tiny goby fishes. My mentor Alcibiades Economou always thought something was worth the detective work at the Mornos Delta. 

Fig. 2. The map in Professor Economidis's article in the periodical "Ι Physis" in 1992. It shows all the major freshwater gobies in Greece with approximate distributions known at the time. It provides an erroneous record of Economidichthys pygmaeus at the Mornos Delta and the question mark of a proposed new species there which he called Knipowitschia stephanidisi - question mark (site 9? in this map). Conclusion: many decades later.. Νο E. pygmaeus or Knipowitschia (or any other small goby) at Mornos Delta - but a new very tiny Economidichthys goby (obviously, the one he called K. stephanidisi), named E. mornosensis. 

The Genetic Evidence

My friend, the naturalist and fish expert celebrity, Jörg Freyhof, came in to help close the case of the Mornos Economidichthys population. We needed a complete review and survey of all populations of the related fish, the Western Greece Goby - Economidichthys pygmaeus. This included a search for the original population in the type locality - where it was first found (on Lefkada), specimens described and published back in 1929. We collected Economidichthys widely and also confirmed a population extirpation at the type locality (Lefkada Island). Within other long-term taxonomic work we are doing on several tiny gobies, along with friends from the Czech republic and Croatia, we now focused on resolving the problem at the Mornos once and for all.

First the genetics:  this was already evident in our publication with Maarten P.M.Vanhove back in 2007. Using DNA barcoding (mitochondrial COI gene), our new chapter in this research confirmed a 5.7% genetic divergence from the Mornos population to its closest relative, Economidichthys pygmaeus. In fish taxonomy, a divergence of more than 2% in COI typically indicates the potential for a separate species rather than a local population variant (however, opinion on such thresholds varies). The COI genetic divergence from Economidichthys pygmaeus is remarkably high despite the more widespread E. pygmaeus being found just 40 kilometers to the west of Mornos (in the river basin, next-door, the Acheloos - Evinos system). This divergance is well above typical intraspecific variation (~0.04% within E. pygmaeus populations!). In other words, the Mornos goby represents an independent evolutionary lineage. Although related to E. pygmaeus it evolved in a different world, within a state of a high degree of isolation.

Fig. 3. Genetic results shown through  phylogenetic analyses (ML, NJ, MP trees); A dendrogram here summarizes the relationships among sampled populations: the Mornos population forms a distinct clade (highlighted yellow), apart from the widespread E. pygmaeus populations; an even more distinctive one is Economidichthys trichonis an endemic of the Lakes Trichonis and Lysimachia. From: the paper, Freyhof et al. (2026)

What Makes It Different?

Beyond genetics, morphology supports the Mornos population distinct species status. Males show a prominent black blotch on the first dorsal fin. The perianal organ is smaller and structurally different from that of E. pygmaeus. The posterior back lacks scales at the base of the second dorsal fin.

The mornos fish is also extremely small — not exceeding 4 cm in total length (TL). Even when reared in large tanks under captive conditions, individuals remained tiny, suggesting that small body size is an evolutionary trait, not just plasticity due to environmental constraint. The species is very close to the size of the smallest adult fish in Europe, the Trichonis Dwarf Goby - E. trichonis (which has an adult size of about 3 cm TL at its maximum). The closer relative, the Western Greece Goby - E. pygmaeus- is by contrast a 'giant'; we have caught several large specimens at 6 cm TL (as published in our fish checklist - Barbieri et al. 2015). 

Fig. 4. Snapshots from our field aquarium photography - comparison of the three species of the genus Economidichthys (not shown exactly to scale; all from the September 2025): The Mornos Goby Economidichthys mornosensis - A,B,C (three adult males shown). The Western Greece Goby Economidichthys pygmaeus - D. The Trichonis Dwarf Goby Economidichthys trichonis - E.  (Photos by S. Zogaris).

So, based on all the above data, we decided to name and publish the new species as: 

Economidichthys mornosensis

The suggested common names are: Mornos Goby and Μορνογωβιός (Mornogovios).

English and a Greek ''common names'' for animals are important and often we disregard the importance of their consistancy. I see no reason not to call it Mornos Goby (as you will read below, we consider it extremely range-restricted). In Greek, I propose a “genus-based compound name” following the naming style used by Antonis Ch. Kanellis and P. S. Economidis. As a side note, Professor A. Ch. Kanellis (1908–1992) was instrumental in compiling the first Greek lists of bird and mammal names. He also had German colleagues who assisted and he adopted the genus-based compound naming method (although, unfortunately, this was sometimes applied somewhat inconsistently and with various errors- long story...). But note, this is important and interesting; i.e., where the generic identity is embedded in the common name — a common practice in zoological naming (e.g., “sand goby,” “marsh harrier,” “stonechat”). Thus, I propose Μορνογωβιός - a compound name,  instead of Γωβιός του Μόρνου (Goby of the Mornos).

A Species with a tiny geographical range - part of an important biogeographical unit! 

The Mornos goby is a stenoendemic (i.e. a very range restricted, narrow endemic species). Based on our studies and our inventory so far, it survives only in small spring-fed wetlands within the Mornos Delta, nowhere else. Its entire distribution covers less than 5 km² and we have found it in only three water bodies in that system (actually just two in the survey of spring and fall 2025). And, there may be a biogeographical reason for this extreme range-restricted state. We did not find it anywhere else in the Gulf of Corinth basin. This is where the biogeography comes in - read on please.

The geological history of the Mornos River is critical here: the river has and always had drained into the Gulf of Corinth, which once was a lake, just before the start of the Holocene. This likely explains the species isolation and the context for its evolution into a distict species. In contrast, major river basins flowing westward into the Ionian Sea host the related Economydichthys pygmaeus - a much more widespread species because population exchanges (as did river confluences) existed among these systems - all facing sea-ward, westward. How many people know the Gulf of Cornith was not connected to the Ionian sea just 13 K years ago? 

So the Gulf of Corinth freshwaters may make up a biogeographical unit of extreme conservation interest- but only its freshwater wetlands, not the marine gulf it is today....Today, most freshwater coastal wetlands around the Gulf of Corinth have been degraded or totally lost. To the east of the Gulf is a strong rain-shadow area - see Galaxidi and Corinth: dry lands and intermittent/ephemeral streams, almost seasonally-semi arid (no long-term freshwater wetlands). And humans have been activley stealing waters and wastefully destryong wetland for a long time. So, the spring-fed flowing waters on level ground, are extremely rare. Most are found solely in the Mornos Delta. The map below shows the guld and the major river basin flowing within it; the Mornos is the largest, with the largest wetland remnants at its Delta. 

Fig. 5. Copy-paste of map of the Gulf of Corinth, with the rivers entering the Gulf - and the Mornos - the largest (blue spot; where the Delta is today - inserted by me). The Mornos therefore did not drain into the open Ionian like the other westward flowing rivers of Western Greece (i.e. Acheloos, Pineios), it entered a former Lake. The Rion Sill is only 60 m. deep; anytime global sea levels were below this depth, the Gulf was transformed back into a lake. This has been going on for at least 5 million years. Map from: McNeill, et al. 2019. High-resolution record reveals climate-driven environmental and sedimentary changes in an active rift. Scientific Reports, 9(1), p.3116.

Specifically what and when was the Gulf of Corinth a Lake?
Here I include references (as cited in Freyhof et al. 2026):

Unlike the other large rivers along the Ionian coast, the Mornos River flows into the semi-enclosed Gulf. This gulf experienced very long periods of isolation and freshwater (lake-like) conditions starting at least in the Late Miocene (~5 Ma). Yes, at least 5 million years ago. Even more extensive lake conditions occurred during the Pliocene to early Pleistocene (~2–1 Ma) (Gawthorpe et al. 2018). Around ~1 Ma, increased subsidence and/or a lowering of the western basin threshold (the Rion Sill) allowed seawater from the Ionian Sea to enter the basin. As a result, the basin changed from a lake into a marine gulf (Lykousis et al. 2004; McNeill et al. 2019); freshwater life probably found refuge in the surrouning riparian wetlands - river mouths, springs. Later, during the Pleistocene glacial periods, global sea levels dropped repeatedly (down to ~120 m below present levels). When sea levels were low, the shallow Rion Sill became exposed, cutting off the marine connection with the Ionian Sea. During these times, the Gulf of Corinth once again turned into a very large lake basin (Perissoratis et al. 2000). After the Last Glacial Maximum, sea levels rose again and overtopped the Rion sill in the late Pleistocene (~13.5 ka before present), restoring marine conditions in the Gulf of Corinth (Mazzini et al. 2023). Because the Gulf of Corinth has had this unusual history of alternating between lake and marine conditions, and because it has long been connected to the Mornos River, freshwater environments in the area likely remained isolated for long periods (i.e. no real or ''easy'' connection to the adjacent Acheloos). This long-term isolation probably promoted vicariant separation of freshwater organisms. Such geographic isolation of freshwater ecosystems from the wider Ionian coastal region may have encouraged the local differentiation of fish species (especially poor dispersers, such as tiny gobies); maybe other aquatic species as well.

Fig. 6. This is a freshwater mussel in the Unionidae family that we found in the Mornos Delta, it is a river mussel! It survived in a spring-fed former distributary channel with the Mornos Gobies! Usually you have mussels only in perrrenial river waters, usually bigger rivers. Our Portuguese colleagues are helping us explore the biogeography of these species - this one is a new location discovery, we never new that they existed in the Mornos Delta. So, due to the biogeographic idiosynchrasies of the river Delta we are now researching other aquatic species, there may be new stories here! (Photo: S. Zogaris).

Under Pressure

Somehow, the wetland wonders that were a refuge to this fish and other freshwater biota survived the ups and downs of a large inland lake, then a sea (back-and-forth). But, they could not easily have survived human-induced wetland and surface water ecosystem degradation (this has been going on for a long time in this 'heart of civilization' area....see Ancient Corinth etc etc). 

Although the Mornos Delta is part of the Natura 2000 network, the remaining habitat faces serious pressures:

• Water abstraction and diversion from springs
• Wetland drainage and fragmentation
• Infrastructure development and scattered construction
• Increasing drought frequency

We saw and photographed in 2025: Illegal dumping, trash heaps and garbage tipping, agro-chemical pollution, embankment and drainage channel digging and clearing, wetlnad in-filling, scattered housing being built, and over-abstraction (or so it seems) from a key hotspot wetland site, immediately above the fish species stronghold (during a drought period). 

Fig. 7. This is a pump-house immediately above the spring-fed wetland hotspot which is a critical refuge for the Mornos Goby (and other species). Please see Fig. 10 below for conditions at the wetland immediately below this pumphouse in Sept. 2025. For years we know of the pump-house, however, we know nothing of its impact on the water levels or spring flow. This area is within the heart of the Natura 2000 protected area - and area zones as highly important. No action on the ground. (Photo: J. Freyhof).

The fish and freshwater biota populations are small and fragmented. Our study suggests the Mornos Goby likely qualifies as Critically Endangered. The delta is also home to the globally threatened killifish Valencia robertae, and prorably other rare freshwater animals. We found the mussel (Unionidae)... If research continues, it could be that this area is exceptionally important for aquatic biodiversity. (Anyway, it is important). 

A Small Fish, A Larger Message

The story of the discovery of the Mornos Goby reminds us that Greece’s freshwater biodiversity may still provide amazing surprises. Small and inconspicuous aquatic species are often the most vulnerable and there is no real concern for them. Scientists and naturalists must speak for them. These biota depend on fragile habitats that are easily altered or destroyed. Legal so-called protection alone is not enough. Without scientific work, active management and habitat restoration, conservation remains only “on paper.”  Protecting this tiny fish means protecting an entire wetland ecosystem at the landscape scale — and the natural heritage it represents. This means an action plan and careful conservation politics  - on the ground. We need to save the landscapes of the Mornos Delta and specifically help protect the spring-fed wetlands within these landscapes. Can we do it? Below I provide some important snap-shots of local conditions. First of all, please keep in mind, this area is a Protected Area.... 

Fig. 8. Within the terrestrial protected areas of the Gulf of Corinth (marine areas not shown) we have the Delta (top left) inside the SCI called PARALIAKI ZONI APO NAFPAKTO EOS ITEA - PERIOCHI PIGON CHILIADOU (GR2450004). In fact, back in 2017, we at HCMR (and with the support of a consortium surveying fish for the Natura project) expanded the protected area to include a critial spring area, the 'Periochi Pigon Chiliadou'. Our ''success'' in this really means ''nothing'' (I was responsible for delineating the new extenstion of the Natura on behalf of the fish - that, nearly 10 years ago). If you cannot promote measures on the ground you are doing practically nothing (see photos below).  

Fig. 9. Landscape scenes from the Mornos Delta within the Natura 2000 protected area (GR2450004). A typical agricultural-domainted, second-home building area and beach tourism hot-spot. Rapid land-use change are taking place. These photos are from Google Maps; I am not making a statement here or propagandizing, there is no conservation action for freswaters on the ground - none at all. 

Fig. 10. One of the most important habitats for the Mornos Goby, a spring area which I intentionally leave un-named since I a fear it may be vandalized or disturbed since, really, there is no real protection: Left: the hotspot area in Sept. 2014 and Right in Sept. 2025.  (Photos: S. Zogaris).

Last thoughts

Looking back, I have been to the Mornos many times in the last 20 years - Alcibiades Economou introduced me to the area. I have been there with nearly a dozen people and I can name them all and cherish memories with them. I was fortunate to visit in 2014 with P.S. Economidis who told us the story of how A. Stephanidis had first collected the mystery tiny goby at the Mornos Delta. I have been there with nearly all my co-workers from HCMR and with wonderful naturalists, such as Nikos Petrou from the Hellenic Society for the Protection of Nature and our brilliant collaborator, Brian Zimmerman from Zoological Society London. Later on we helped expand the Natura 2000 boundaries there. All this reminds of what we do - rarely talked about - Natural History - and for this you need inventory and taxonomy.

I would like to express my sincere gratitude to everyone who has worked to collect aquatic animals and study their taxonomy in this country, including our collaborators from abroad. Taxonomic research requires decades of careful fieldwork, in-depth study, data-management, collection management and long-term dedication. This type of work rarely receives substantial funding or recognition. It is sustained mainly by the curiosity, commitment, and perseverance of naturalists who are driven by a genuine desire to understand biodiversity. In fact, most people work behind the scenes, they are not even mentioned in the scientific articles. Such combined efforts provide the foundation for evolutionary research, biodiversity promotion in our cultures and conservation policy, and conservation actions. May we continue to collaborate, support one another, and advance this work with the same dedication and scientific integrity.

The paper: 

FREYHOF, J., GEIGER, M. F., & ZOGARIS, S. (2026). Economidichthys mornosensis, a new freshwater sand-goby from Greece (Teleostei: Oxudercidae). Zootaxa, 5759(1), 26-40.

Our paper with the full details is available from the Authors through ResearchGate:

https://www.researchgate.net/publication/400759296_Economidichthys_mornosensis_a_new_freshwater_sand-goby_from_Greece_Teleostei_Oxudercidae

Our man in Lake Baringo: Joseph Aengwo

 Focus on Ecoguides: Joseph Aengwo

February 2026 - Kenya (our third Fam tour visit)

I’ve always wanted to talk more about the eco-guides — about the people who quietly dedicate their lives to it.

We often celebrate destinations. We photograph landscapes. Tick species off our lists. But we rarely pause to acknowledge the individuals whose deep knowledge, lived experience and interpretation abilities make wildlife tourism and nature promotion possible.

This is one of those stories.

On a recent FAM trip to Lake Baringo in Kenya, I had the privilege of meeting someone who embodies what true "eco-guiding-with-a-local" is all about: Joseph Aengwo, one of the famous bird guides who began at Baringo but has developed a company, now guiding nearly everywhere in East Africa.

Joseph is a prominent and highly experienced ornithological guide from Lake Baringo. And when I say experienced, I don’t just mean he knows bird names. I mean he understands birds really deeply and their environment too— how the Rift Valley breathes, how the seasons shift, how bird calls change with the light.

Born and raised on the shores of Lake Baringo — a true birding haven in the heart of the Rift Valley — this landscape is not just his workplace. It’s his boyhood wonderland, memory, culture, heritage.

This was one of our top birding targets at Baringo, the Northern Carmine Bee-Eater. Tick at the Baringo Lake causeway to the Tumbili Cliffs! 

Professionally, Joseph is formally trained in tourism and wildlife management from Moi University. He is also a bronze badge member of the Kenya Professional Safari Guides Association — a credential that reflects both skill and commitment to guiding standards in Kenya. But what truly sets him apart isn’t the certification. It’s the way he guides.

There’s a quiet confidence in how he organizes guiding. A patience in how he adjusts to the clients/guests. A generosity in how he shares stories — not just about species, but about conservation, community, and the life-forces that keeps Lake Baringo thriving. 

Joe also has been active in conservation and he knows the situation of the lake ecosystems very well. Also, he has a great sense of humour...our man in Baringo!  

He told us there are now about 20 boys (and a one or two girls) involved locally in nature conservation actions, and some of them are active in in ecoguiding as well;  most of them beginners. We met two of them who had staked-out owls and other cryptic birds for Joe. Joe is still associated with the Lake Baringo Biodiversity Conservation Group (LBBCG) formed in 2008, a non-profit local environmental group that plays a role striving to protect this place. The group aims to promote community awareness on environmental conservation and protection of key species sites and habitats, also encouraging community participation. Its all very low-key, very informal. We saw very few tourists. 

Now all these pics may bring to mind a wonderful beautifully managed and manocured National Park. But this is not to be in Baringo!  The situation here is not protected, its not a fortress park or any such park. And there are problems. Things are rapidly changing and there are also issues of serious poverty. The lake waters have risen substantially in the last few years, displacing people, flooding wildlife habitat and ruining agricultural areas, drowning villages. Between before 2009 and late 2020, Lake Baringo’s water level rose by approximately 9.5 meters (from about 972 m to around 981.5 m above sea level) — a dramatic rise over roughly a decade.

This situation is unusual, but it is also seen in Lake's Bogoria and Naivasha, also to a lesser extent at Lake Nakuru. 

The main hypothesized causes based on current understanding point to:

🌧️ Chagnes in Rainfall patterns (more intense rain) and catchment changes (vegetation change; increased run-off). These are currently the most strongly supported explanations for the main driver of  the recent water level rise.

🌍 Geological forces - unknown. The lake’s tectonic context matters for its hydrology, but there is no definitive evidence that plate movement is the main cause of the contemporary lake level rise.

🧠 Some discussions about underground fault-seepage changes exist, but they remain hypotheses rather than confirmed causes.

Also, despite this serious and unresolved problem of the lake waters, the area has a strong wildlife - human population conflict too. Large mammals are scarce. Poaching is rampant and displaced peoples have settled in difficult conditons. Overgrazing is also a serious problem. 

So, in this case, organized ecotourism may support and promote solutions to these big problems, big landscape scale measures are needed for conservation. Of course, since we work in science of this sort, we also would promote science-led initiatives to deal with such serious issues. This place is too important to neglect!

Rhinos and Giraffes and other mega-mammals once roamed below these hills onthe shores of the lake, now there is nothing like that. Poaching is a problem. This beautiful and huge landscape is not protected and there are serious problems. 

Joe with one of the best Birders in Bulgaria, my good friend Tihomir Stefanov. This is the causeway to the Tumbili Cliffs- amazing place for birding and fish-watching.

The endemic Baringo Tilapia - Oreochromis (niloticus) baringoensis. 

This amazing semi-desert, arid land beauty. And full of birds.

Verreaux's eagle (Aquila verreauxii), used be known simply as Black Eagle when I was a kid. Rare bird indeed.

One of the most captivating places for birds are the famous Baringo cliffs. 

Looking accros the lake to the islands; a short rain-shower blessing the landscapes. 

Rising waters of Lake Baringo, looking north, from the causeway near Tumbili Cliff Lodge. 

The lake as viewed from Tumbili Cliff.

The location of Lake Baringo in the East African Rift Valley. A critical problem is the water level rise. Maps from: Herrnegger M et al. Paleohydrology repeating? Regional hydrological change may lead to an overflow and cross-mixing of an alkaline and a freshwater lake in East Africa. Journal of Hydrology: Regional Studies. 2024 Oct 1;55:101951.

Joseph Aengwo

Have a look at Joe's website at: https://kenya-birding.com/

Cell Phone: +254 727 856 048
email: joe.aengwo@gmail.com

Also, we thank our good friend DERRICK MURIUKI GICHIMU who rents out the best cars for any Safari. Derrick is one of our best friends in Nairobi and he knows Kenya. Find Derrick at: muriukidgichimu@gmail.com or at: Kompact safaris Kenya car hire | budget friendly Kenya car hire/ self drive 4x4 Nairobi

Electrofishing the large rivers of Western Greece - the Ionian Freshwater Ecoregion

I’m posting a handful of snapshots boat electrofishing in the rivers that spill into the Ionian Sea. Western Greece is often described with postcard words—gorges, plane-tree galleries, turquoise springs—but for a freshwater biologist the real poetry is in the fish.

These river and lake basins sit in an ecoregion of unusually high endemism. In plain terms: many of the species we net here exist nowhere else on Earth, restricted to a single basin or to a tight cluster of neighbouring basins. Each river is its own little evolutionary archive, shaped by histroical isolation, ancient geographical barriers, limestone karst and local ecological dynamics. You can feel that history in the bucket: a familiar “Mediterranean” fish assemblage, yes—but also odd local forms, subtle variations, and those small, secretive fishes that only make sense once you’ve seen the ecosystems that produced them.

Boat electrofishing looks dramatic (and, inevitably, people ask if it’s “fishing”....). It isn’t sport; it’s scientific sampling—carefully standardised, short pulses, tight safety protocols, capture technique and quick handling so fish can recover and swim away. The routine is half choreography: the skiff sliding along a run, the anode poles probing the margins, dip-nets ready, data sheets getting damp, GPS logging each transect. Meanwhile, we’re also reading the river: flow, substrate, cover, riparian conditiosn, the scars of water abstraction, the shadow of barriers, the die-back of the platanus trees due to an alien fungus invasion; the occasional surprise of an alien species where it shouldn’t be.

And still—despite multiple pressures and degradation—these Ionian rivers can feel astonishingly alive and wild. Every survey reminds me that conservation here isn’t an abstract idea. It’s local, basin by basin, decision by decision. Protect the habitat, and you protect an entire, irreplaceable lineage.

 

Fish Pictured here include (in order of appearance): Economidichthys pygmaeus - Goby, Knipowitschia sp. - Goby; Squalius peloponensis - Chub; Luciobarbus graecus (with D. Kommatas) - Barbel; Dicentrarchus labrax - Sea Bass; Luciobarbus albanicus - Barbel; Knipowitschia sp. - Goby; Liza (Chelon) ramada (in net) - Mullet; Salaria fluviatilis (juv.) - Freshwater Blenny; Alosa fallax - Twaite Shad. 

My colleagues: Alexandros Ntakis, Dimitris Kommatas, Vassilis Pappas, Anthi Economou and Petros Chronopoulos. Some pics taken by Vassiliki Vlami who was also on one of the trips. And again my thanks to HCMR, we are so grateful to work there...

You are also welcome to download one of our recent papers on the fish assemblages within this Ecoregion: 

Fish_assemblage_taxonomy_highlights_spatial_patterns_of_b-diversity_within_a_freshwater_ecoregion

And a map by my good colleague Theocharis Vavalidis from the above paper. The major river basins where HCMR does electrofishing using a boat are numbered as so: 1) Kalamas, 2) Acheron, 3) Louros, 4) Arachthos, 5) Acheloos, 6) Evinos, 7) Mornos, 8) Pineios, 9) Alpheios, 10) Pamissos, 11) Evrotas.