domingo, 3 de mayo de 2015

Titicaca expedition: lago menor, the massive mortalities

Collecting the dead frogs in the Lago menor
Today we were working in the lago menor side of the lake, our first two localities were not so different than before, even in one of the localities the water was not green anymore, but we noticed a big amount of zooplankton in the water, probably a normal situation after an explosion of phytoplankton.
We were travelling a lot to try to cover different areas and at the end of the day we went out by boat just some minutes and when we arrived to a spot of 3 meters by 2 we were able to find in less than 5 minutes 106 dead individuals, this with almost no effort just getting with the net the frogs that were floating in the surface of the lake, but we also noticed that there were much more individuals under the vegetation, but we did not take all these animals because was almost night.
Some of the dead frogs in the lake
With the samples we are collecting until now we saw that this event caused the death of these frogs from 5 to 10 days but the villagers told us that before there were much more but they took out those because the smell was very bad. From all the dead individuals we found we carried out some post-mortem analysis and we found that most of the dead frogs were females with eggs and in several cases the frogs had a not normal muddy substance as gut content.
Taking out the dead frogs
We are trying to collect as much samples as possible for future analysis and to try to understand what is causing this problem that it seems that is associated with the water that arrives in the rivers of the region every rainy season. But talking with the people here they say that is the first time that this happens at that scale. Also for us it was impressing to see that amount of dead frogs and even we saw in the past several deaths, we never saw at this scale.
Postmortem analysis, several females with eggs

Tomorrow we are going to start working with the boat in the area to see how the situation is; also diving in the area to see how is going in the open areas where normally the frogs are also present.

Working with the postmortem analysis

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