Song of the Whale Diary: 5th - 9th October

Sunday 5th October
Written by Mark
I returned to Song of the Whale today for the first time since finishing as field assistant last year.  After an early flight yesterday morning when it was 2 degrees C in the UK I stepped off the plane into a pleasant 28 degrees C in Tenerife.  An overnight stay and a ferry trip later I arrived at the boat to catch up with the Song of the Whale team. The nature of the work this year is in stark contrast to the sperm whale population survey undertaken last year. This year the boat is working with a land based team, last year we usually couldn’t see land. This year it takes 20 – 30 minutes to complete a transect line, last year it could take a couple of days. This year the survey area is a few square kilometres, last year it was the entire eastern basin of the Mediterranean! It’s interesting to see the different methodology used this year and demonstrates the adaptability of the vessel. As evening falls we head out of the harbour to do some acoustic surveying overnight, then tomorrow morning we will make contact with the land team and continue our quest for the elusive beaked whales..

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Monday 6th October
Written by Mark
We continue our night offshore survey until 7am when we break from our track line and head back to the near-shore survey area to start working with the land team at 8am.  After some nice acoustic detections we have a sighting of a group of beaked whales in the early afternoon.  In the early evening we head back to La Restinga to drop Patricia back off with the land team and pick up Monica.  Around 9pm we head back out for another night long offshore survey.

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Tuesday 7th October
Written by Claire
The weather is nice and calm this morning, and we have been picking up some good detections through the night. However, we have been noticing some strange clicks on our detection software that appear to be coming from the hydrophone itself. Having finally got it working well after so much trouble this year, this is the last thing that we want. We carry out some tests with different towing speeds and so on, but we are unable to determine the cause. The clicks themselves are not too problematic, and when we stop still and let the hydrophone sink vertically, they disappear, so we are still able to detect animals. Hopefully it won’t get any worse. Throughout the afternoon we have some nice, close sightings of Cuvier’s beaked whales and are able to get some good photo ID pictures, as well as some detections, so for the moment at least, all is well with the acoustic systems.

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Wednesday 8th October
Although the study site off of the south coast of El Hierro is sheltered in many weather conditions, as you get slightly further off shore, you start entering acceleration zones where the wind can get very strong. These are caused by a funnelling of the trade winds around the high, mountainous islands. Overnight we were carrying out some offshore tracklines to see if beaked whales are also detected further off shore, and consequently sailing in some of these zones. This made for rather a rough night. As we go in towards the island again at daybreak we start to get shelter and the sightings conditions are pretty good. The ULL/WHOI group also have their boats out today, and the land team works hard to keep everyone abreast of all of the sightings. We see some Blainville’s beaked whales from the boat and spend some time trying to get some recordings in the area where they dived. When we look back at the pictures we have taken today, we see that we have seen one of the animals before – it has a very distinctive scar on its left flank.

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Thursday 9th October
After another rough night we are greeted at daylight by a very small patch of shelter in which to work today. Rather than the usual north-easterly winds, today we have westerlies. It has also been too rough for the ULL/WHOI group to get their boats out and so we have no land station today either. Despite this, we have beaked whale sightings and detections fairly early on, but by 1400 the sheltered patch is disappearing and we have had no further sightings or detections. We soon decide to head back towards La Restinga.