Posted by Kurt Schaefer
Thursday, 23 June 2011
At 0445 h on the morning of June 19th, the weather held true to the forecast and the wind was in excess of 30 kts and the seas were very rough. The sonar mark of the aggregation at the FAD where we had been conducting our latest studies was still present and probably over 50 tons of tunas were present. It would not be possible to make a set that morning under such unfavorable and dangerous conditions. It would be necessary to jog back and forth with the Yolanda in the vicinity of the FAD, rather than just drifting nearby, as there was concern in such rough conditions about the stability of the vessel and more so the workboat on the deck of Yolanda. The weather remained quite severe throughout the afternoon of the 19th, with the strongest winds and roughest sea state yet experienced during this cruise. One of many reasons we have sincere respect and caution for the ever-changing moods of the sea is the 48 h change from the best to the worst sea state conditions.
The morning of June 20th at 0500 h, the Yolanda approached the FAD under somewhat better weather conditions to evaluate the aggregation at the FAD and determine whether it would be possible to make a set. Unfortunately, based on the sonar, it appeared a good portion of the aggregation had dispersed and there was less than perhaps 30 tons of tunas remaining. Furthermore, the weather was still rough, but of greater concern was the current, which had increased to about 2.4 knots and was now too strong to consider making a set without taking an unnecessary risk to the vessel and equipment, including the net. We decided we would abandon this FAD and move on to another in a different area to begin our 7th set of experiments and hopefully conclude those with a successful set, should weather permit. A speedboat was deployed to retrieve the VR2 from the FAD and we had already downloaded the enlightening data collected over the past 4 days.
We should be arriving at a promising FAD in an area to the east tomorrow morning, 21st of June. We will be carefully evaluating the weather forecast between now and then, and hoping to get another window of opportunity to deploy the workboat and undertake the 7th set of experiments. I look forward to informing you about the outcome of our next series of field experiments on tuna behavior, following their conclusion.
Until then, all the best from those of us aboard Yolanda,