Survey 2020 Aitoliko Lagoon
Diving and Data Calendar of the presence of seahorses in the lagoon of Aitoliko – Messologgi
Date |
Divers |
Dive in |
Dive out |
Temp |
Location |
Description / Remarks |
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Lampros Charelos |
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Lagoon Aitolikou – Mesologgi
Lagoon Area: «Agios Elias»
Map attached |
After contacting Lambros Charelos with us, we were informed about the existence of a population of seahorses in the lagoon of Aetoliko. Lambros Charelos is a professional diver who lives permanently in Aetoliko and works in fish farming in units in Astakos. He often visits the lagoon, fishing for small-sized sea bream and cephalous fish. He has been observing seahorses for almost the last 2 years. The seahorses made an impression on him, where he has been monitoring them systematically for the last 2 years until today. At shallow depths and in brackish waters with limited visibility, turbid waters often meet mainly large seahorses. Hippocampus gutulatus, has been found almost all over the lake, but mainly in the main area of Agios Ilias. Probably some end of land water vein, the fact that this area is more remote and isolated, are just working cases for a first interpretation of the preference of seahorses in the area of Agios Ilias. Then our communication with Lambros was almost weekly, where he informed us about the number and size of the seahorses he located, the point, the temperature and the depth. He sent photos and videos. So on May 30, a group of 2 people from the institute left Athens to meet Lambros and dive in the area of the lagoon of Aetoliko in Agios Ilias. |
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30/05/2020 |
Manos Mitikas Vasilis Mentogiannis Lampros Charelos Vasilis Galanis |
11:30 |
14:30 |
23,5c |
Lagoon Aitolikou – Mesologgi
Lagoon Area: «Agios Elias»
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Diving in the lagoon of Aetoliko, area of Agios Ilias. Following Lambros, we started a coastal South-East course, at a depth of -0.5 meters to -2.5 meters. Visibility did not exceed half a meter and the bottom is very rich in mussels, tiny crustaceans and many more. With a relatively large dispersion and frequency over a period of about 2 hours and a distance of about 350 meters, we identified more than 25 large individuals. The vast majority of them are male. At depths from 0.5 to 2 meters. At 15 seahorses I stopped photographing them numerically and continued just holding the total number. The area offers perhaps the best possible camouflage. Making them very difficult to locate. Medium-sized as well as small seahorses were not detected at all. Obviously, it is very difficult to locate them and observe them. All of the seahorses found were of the Hippocampus gutulatus species only. In one seahorse, we installed 5 cameras for about 3 hours, recording time lapse video every 5 seconds. In addition to the remarks on the hippocampus, one water snake passed through the video area, was also impressive. |
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31/05/2020 |
Manos Mitikas Vasilis Mentogiannis Lampros Charelos
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10:00 |
13:00 |
23,5c |
Lagoon Aitolikou – Mesologgi
Lagoon Area: «Agios Elias»
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The next day we also dived in the same area but moved independently underwater, to perform different tasks. Manos and Lambros conducted a method for measuring transects. The methodology is the development of a 50-meter-long metro tape (route). At point “0” start and end point “50”. Investigation of the 50-meter route, by a diver on each side of the metro tape. The diver to the left of the tape recorder records the existence of seahorses up to 3 meters away from the tape recorder. So we have: At XTH 00, distance of 1 meter, normal to medium-sized female. At XTH 02, distance 3 meters, large male. At XTH 47, distance 3 meters, large male At XTH 49, a distance of 3 meters, large male
A total of 2 seahorses were found on the land side. At XTH 03, distance 3 meters, large male At XTH 50, 1 meter distance, large male
A total of 6 seahorses were found on a 50-meter-long and 6-meter-wide route.
We also installed 5 cameras for about 3 hours, recording time lapse video every 1 second to monitor and record a seahorse.
Then with the boat of the president of the fishermen Mr. Kargiophyllis Spyros. We did some salinity measurements.
Water column salinity measurements. The instrument was the YSI Pro30. So we have the following measurements:
*Parts Per Thousand
In conclusion, we have a successive decline in theocracy in the water column from the surface to the bottom and an increase in salinity. |
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Some conclusions: The picture of the lagoon is encouraging, estimating that the population of seahorses are estimated to hundreds. As Lambros Harelos informed us, seahorses of the species Hippocampus-hippocampus have been also identified in a northern part of the lake where the bottom is characterized as more sandy. In the area we explored at Agios Ilias, the seahorses do not seem to be threatened, as they are in shallow waters and the morphology of the bottom does not allow fishing with sliding tools. The president of our fishermen informed us that they relatively often catch seahorses in their nets. He told us “20 years ago, there were thousands, that was well known! Now the lagoon is dying, at -4 meters the water is anoxic, without oxygen”. In fact, during our first dive, I headed deep to explore the area in greater depth. I noticed that after -4 meters, the environment becomes gray, dark and at -5 meters I did not notice any living organism. A dense hydrogen sulfide zone has turned most of the lake anoxic. The lake is dying. Sweet water and fertilizers, aggravate the waters of the lake. Reducing its enrichment with fresh seawater further aggravates its condition. I also send you what I was able to locate from relevant literature (unfortunately in Greek language), I have spoken with a x director of the institution whose recently ceased operation and I have also contacted with the University of Patras.
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