Friday, October 2, 2015

Barriers to fish movement: Tributaries of the Sperchios river

Road crossing creating two meter drop impassable for migrating fishes. This is serious pressure on natural fish communities.

October 1st 2015 West slopes of Mount Iti, Sperchios River Basin.

After the first heavy rains trout move and migrate. They encounter barriers. Some natural some human-made. Upstream of these barriers rivers change - if the barriers are human-made the result is river degradation; a fishless river.

Here in the mountains of the southern tributaries of the Sperchios in Central Greece we are studying river fish communities; trying to interpret what we observe. Sometimes we find no fish at all...but in perfectly natural clean wild's because of the barriers!

The photos below were taken when our three-man team was accompanied by the naturalist and photographer Thanassis Skouras just a couple of days ago. Thanassis helped us electrofish as a volunteer but also took loads of photos. So I am posting them here as a memoir to this wonderful and typical day of fish research.

Our HCMR team is working to build an inventory of fish assemblages and environmental conditions and learning a lot. We are listening to and observing river life. What a wonderful feeling to build a knowledge base. I just feel I should say how privelaged I feel to be learning something that can help systems like rivers be better managed. And restored.

Photos above show typical four-person electrofishing in a mountain catchment ranging from about 600 m. to 300 m asl (some of these within the Iti National Park region). You may notice barriers in the background: a road crossing and hydroelectric plant. Some stream sections have fish others none (but we did find some Salamanders in a beautiful cold-water spring). Most of the fishes caught here are Trout (Salmo cf. fariodes) and a very few Sperchios Barbel (Barbus sperchiensis). Thanks to Thanassis Skouras for the photos and my great colleagues Sofia and Yannis.

Also for anyone genuinely interested in the issue of upland stream within Iti National Park please have a look at one of our first expeditions in the area in November 2012 at: Ichthyological_survey_of_the_major_montane_streams_of_Mount_Iti