Hello my name is Miss Gillingham. Please join me as I travel to Greece to study the dolphins of the Amvrakikos Gulf!

Sunday, August 14, 2011

The 5th Day at Sea - Dolphins Everywhere!

How can one not be impressed by Amvrakikos? Especially on a day, when dolphins were found in abundance. Today we headed to transect G on the other side of the gulf. Scanning the horizon, Joan pointed out indicators to help us locate dolphins that may be far away. For example, flocks of birds often dive around where dolphins are feeding and try to snatch up some tasty morsals. Can you see the birds in this picture? I will get better ones to post from Joan later. Sure enough, in no time at all, everyone was calling out spottings. From almost every direction. We had been assigned an area to keep watch off so if 12:00 was the bow (front) and 6:00 the back we could cover 360 degrees around the boat and identify the location. Of course in our excitement we forgot half of what we were suppose to say (the where and how far) until Joan calmed us down and chose our focal group. This group we were to follow no matter what else was seen in the area until we had obtained enough data or the dolphins chose to leave us behind. Can you see the dolphin behind me? I also have a video to add but so far no go but I will work on it. The main objective Joan and his team have been trying to answer is 'How many dolphins live in the Amvrakikos Gulf?' and 'Are they residents or migrantory?' Over the years, since 2001, the evidence points to bottlenose dolphins living in the gulf. They had tested just outside of the gulf where dolphins could enter from the sea and only one group of dolphins were ever found, none of which entered the gulf. This is important because the Amvrakikos is the dolphins home. Whatever happens to the gulf then can affect the dolphins.

Thankfully, none of the bottom trawlers or purse sieners we discussed earlier are allowed here, only small sustainable fishing is allowed. This means there is plenty of sardines (the main diet) for dolphins to eat. Yahhh!Do you remember the European Pilchard I mentioned in the first blog? It is a type of sardine. Also, there are no predators, like sharks - Yahhh again. So we should have happy and plentiful dolphins. Can you see the contrast to the Kalamos region we visited before? Like Kalamos however, the main threat to dolphins is us (and looked what happned to the wildlife there!). Because we have seen what can happen (we have proof!)we need to be extra careful.

In the past few years however, there have been quite a few changes to the gulf that may be having an effect. Firstly, a port has been built that has reduced the width of the channel uniting the gulf and the sea (from 700 meters to 370 m) which prevents circulation of the water. Also dams and irrigation can reduce the water coming into the gulf while farming and nearby cities add pollutants. As we saw earlier, pollutants are high enough in the gulf to prevent people from eating the mussels that live here. This has made the waters 'eutrophic' a fancy word to mean high in nutrients. Which is normally a good thing until there are too many. Too many nutrients can reduce the oxygen levels in the water. Thankfully for the dolphins, who breathe above the water, this doesn't directly affect them, however anything living below 20 meters will struggle. Keep it up and the food source for dolphins will also find it difficult to 'breathe'.

There are numerous concerns that I will need to get more into later but for now it's time to go and identify what we have found. By looking at the photos Joan has taken we group dolphins with the same 'indents' together then compare them to the data base of dolphins they have seen before in the area. In the photo below Ioannis and I are comparing past photos Using our new skills, I am going to run back to the reseach base to identify what we saw today and even add some new ones to the group - two babies (calves)ahhhh. Don't worry, I'll beg Joan for a photo :-)


2 comments:

  1. You must have had to be very strict with yourself to not look at dolphins at the other side of the boat when they arrived! I suppose that's the difference between being part of a scientific survey and a pleasure cruise (not very scientific if dolphins aren't being counted because over excited humans are looking the other way!). It must have been torture at first though (thankfully you saw lots more).

    ReplyDelete
  2. Do the oxygen levels reduce with too many nutrients in the water because algae forms?

    ReplyDelete