Athens Nature Journal: Peloponnesian fish survey: Let the fish speak!

July 24th 2013

Fish sampling in the freshwaters of the Peloponnese. In five days, we managed to sample 25 sites in a standardized way using electrofishing gear. It is normally inconceivable to sample so many river sites so rapidly, but I know most of these areas from previous monitoring and this time....we were in the mood for a rally....

Some of the results of this "trip-at-full-tilt" follow in point-form below. The map above show the major areas sampled and a rough sketch of the route we took from Athens. In refering to the fish species I try to use English fish names to follow the example of birding narratives...Where I give the acronym (cf) for "confer" after a fish name I mean that the identifications of the fish taxon requires confirmation, and we have collected samples in order to confirm IDs. Fish tell us a lot about local conservation needs, I hope we can cope with the many unmet needs in the Peloponnese....

ARGOLIS

- At Nea Khios wetland we found two brackish canal inflows to the coastal wetland but no fish other than Mosquito fish. We could not search this area well and should come back to it.

- The Springs of Lerni still hold Stymphalia Minnow(cf), Freshwater Blenny and Three-Spine Stickleback!!! We were worried the freshwater fish populations had collapsed after a near-total drying-out of the springs due to a long drought several years back. The Lerni Spring site is a conservation priority and the site has been damaged recently be infilling works for recreation development (shoreline infilling and reed removal). A nearby spring tributary just north of Lerni (in Milos) has an outflow to the sea and it held Freshwater Blenny and Eel also. (We did not find the so-called Roumani Marsh nor did we visit Kefalari springs a bit further north: the last remaing freshwater habitats in this part of the dry Argolid).

THE NORTH

- We discovered a population of Peloponnesian Chub (cf) at upper Assopos (Near Petri Village, Nemea) along with Stymphalia Minnows!!! This river had been also hit by drought/over-abstraction for agriculture- and the fish in these cold spring waters were a surprise! The waters were a cold 15 C and they had a few Rainbows - we took 4 of these alien trout specimens for a friend in Klitoria....

- Stymphalia lake has low water levels this year and the Phragmites is choking most of the lake, the eastern inflow tributary had Stymphalia Minnows and we observed some very elusive chub also. (We caught only a couple of fry of the Chub...could this be be alleged Stymphalia Chub???).

-Former Kandila Lake (drained in early 80s) was disappointing. Only very few Stymphalia Minnows (cf) and a few Mosqitofish (Gambusia) in the Canals; the very cold springs were fishless.

- Vouraikos has very polluted cold waters above Kalavrita - so severe was the polluted water that one site had no fish or amphibians. (Oddly enough there were plenty of marsh birds such as moorhen and rail in the thick reed-mace and reed). Further upstream we found what looked like Peloponnesian Chub (cf) - these are allegedly the Stymphalia Chub but they look very very similar to other Peloponnesian Chub to me. We sampled at the Bridge to Kertezi - the water was unusually cold and fish densities were low...

NORTHWEST

-At the river Vergas, upstream of Kotychi Lagoon, we documented a new record of Gournara (Tropidophoxinellus hellenicus) - a beautiful "carp-minnow" of Greece's west coast. The neaby Pinios had lots of these fish above the Pinios Reservoir. Vergas is severely threatened by over-pumping of waters for agriculture. Only about 1 km or less of refuge-like "water ribbons" are left in the middle part of the drainage, near the village of Nisi. We also documented (re-confirmed) the existence of the Alphios Riffle Dace which was locally abundant here (a total of 5 fish species, but no Eel we found).

- On the main tributary of the Peloponnesian Pinios, about 1 km above the Reservoir (near Kalivakia village) we found 9 fish species and documented Carp and Gibel Carp in the river system - I think for the first time in this river. Fortunately no Sunfish yet in these warm waters (temp: 28.6 C). Gibel Carp is a notorious invasive which was not spread in many Peloponnesian rivers yet (as opposed to what has happened in Northern Greece), but we did find it on the tributary of the Ladon (of the Pinios) near Efyra also.

- At Alphios, beneath the Alphiousa Dam, hydro-peaking effects from the large irrigation dam have severely altered fish communities. Perhaps river mining activities are also to blame. No Stymphalia Minnows were found, and fish densities were low. We did manage to find 9 speceis: Sunfish included! The hydropeaking effect on the river persists even below the national road bridge near Epitalio. Very very few freshwater fish down here (although we found large numbers of mugilids in the rapids cascading down the base of the bridge). Sunfish was recorded here this time too! Fishermen fish for Sea-bass here also.

SOUTHWEST

- At Peristeras (near Kalo Nero) we caugh a Sea-Bass. It looks like a Spotted Bass (Dicentrarchus punctatus); the first I have ever seen in Freshwaters in Greece - if my ID is verified since it is a small individual (about 19 cm, but fully spotted...). Remarkable concentrations of Eels and Freshwater Blennies were found both at Peristeras and Neda (beautiful rivers!).

-At the pretty little river of Yiannousagas (near Pylos) we found very few Peloponnesian Barbels -their populations are extremely low in the warmer, lowered-flowing reaches due to abstractions for agriculture and tourist developments. The river once supported two water mills we were told and Barbels grew large and were actively fished by the locals (we were told....). Freshwater Blenny numbers were also low now; again, perhaps a sign of water abstraction stress on the river (at the riffle-pool portion downstream of Schinolakkas Village). We were told the water is now also abstracted for new Golf Courses and we saw large reservoirs for the Golf lawns nearby...

- At Finikounda we found a stream with very little water; later we searched downstream and found some very stagnant scour-pools with coolish water! (22.9 C). But very very few fish - a total of 3 Spartan Carp-Minnows (Tropidophoxinellus spartiaticus) were seen here along with grey-mullet, eels.... and terrapins.

- A beautiful small river exists near Nea Koroni. Locals say there are Otters here (or were). Anyway, we found a clear blue pool full of Spartan Carp-Minnows and many many eels! Upstream the river is dry and it no longer reaches the sea in Summer. But what remains here is a little peice of paradise...

- We searched the Pamissos and found a couple of Tench at Valyra (much smaller the ones our team had caught and cooked back in '09). These are introduced fish so we feel fine to do this sometimes. Valyra seemed polluted this time. But still lots of Eels here.

- Meligalas a few kms upstream was not polluted. Here the Pamissos was at its full glory and full of fish, including pretty little Stymphalia Minnows and huge Peloponnesian Chub (cf) that ware looking kind of "different" to us (taxonomic work on the Chub here is a must...).

SOUTHEAST & CENTRAL

-At Evrotas, just upstream of the Bridge of Sparti I was in awe....what a magnificent Mediterranean river. Cold-water (17 C in the morning) and full of fish, dice snakes, amphibians. Paradise.

- I visited Lake Taka for the first time. I was told by our team that in the past the area was full of Stymphalia Minnow, now we found none. A huge reservoir has been constructed and the pools left by the earth-works excavating earth for the embankments were full of alien fishes. He found Economidi's Goby (aka Western Greece Goby) here - perhaps the first recored of this transplanted speceis in the Peloponnese!!!. Also there were "Southern Greek" Roach, perhaps from Lake Trichonis - we not sure; and Gibel Carp (along with Carp). And the place was crawling with Sunfish. Sunfish everywhere... What a pathetic ersatz ecosystem -a totally artificial assemblage!

- We found a single Peloponnesian Barbel (!!!) near the village of Karkalou in the upper Lousios. This was a surprise because this cold-water upper part of the Lousios had only a few Peloponnesian Chub (cf) back in 2002 when our team last fished here. Who knows how these fish got into this isolated montane basin at 900 asl. Another mystery.

CONCLUSIONS

Fish, like birds, should be actively "used" for conservation and resource management and impact assessments. But fish are "invisible" to most people.... The impacts of wetland abuse and water mismanagement in the Peloponnese are severe. A new problem is the issue of invasive alien fish species. A long-lasting problem is the great issue of research gaps in taxonomy, biology and ecology of the fish species, many of which are seriously threatened. Inventory and monitoring is a must. Popularizing this knowledge is also critically needed.

DETAILS

For the record, specialists my be wondering how its possible to do so many electrofishing samples so rapidly. This was a two-man trip, it would be much better to have three persons. We slept about 7 hours each night, often just past midnight, we usually ate on the road (quick pic-niks), not at restaurants (two exceptions). We ate light and rarely took alcohol. We slept at the following places: 18/7: Argos, 19/7: Kleitoria, 20/7: Amaliada, 21/7: Gialova, 22/7: Sparti. We shared in driving and used only one back-pack electrofisher (Smith-Root 24 L).We electrofished at least 40 meter stretches but oftentimes at least 100 meter stretches in rivers or along lake and wetland shores. The observed fish composition, fish numbers, size-classes per species were recorded immediately after each sampling event. Since we collected the caught fish and later photographed them we could confirm compositions and relative abundances with high accuracy; however it is more accurate to do this while e-fish sampling on-the-spot (therefore the need for a third person keeping protocol...). We recorded both caught and observed electrocuted fish abundances. We also carefully recorded habitat data after each sampling event (using the HCMR Rapid Ichthyo-Assessment Protocol). Each site was photographed and often filmed. This work was an HCMR and Czech National Museum collaboration. I thank my friend Dr. Radek Sanda for being such a great companion on this exciting trip -well worth it!