Saturday, September 5, 2009

End MED-09

Today marks the end of operations for MED-09 after over 5,000 nautical miles covered across the western Mediterranean Sea. We could not try to tag animals today since we needed to leave the operational area by evening, but we attempted to run some additional visual and acoustic surveys to add to the biological data already obtained. The seas were not friendly, however, and as we got further north they became rougher and we had to break off the surveys and begin the trek back to LaSpezia. We had sustained winds of 35 knots, with gusts of over 40 with large waves rolling the ship most of the day as we left.

While all of us are looking forward to being back on land for different reasons, we are also sad to see this project come to an end. We have had assembled, on an outstanding and quiet research vessel, an all-star team of specialized experts from around the world. What we have been trying to do is incredibly difficult -- measuring behavior in some of the most challenging animals on Earth to study. Certainly there is some disappointment that we were not able to tag and conduct controlled exposure experiments on beaked whales. But that is counterbalanced by some of the significant accomplishments that were made in this project, many of them related to improvements in methodology and technology in working with such difficult species.

Perhaps our most significant accomplishment was refining and demonstrating the ability to use an integration of visual and multiple acoustic methodologies to follow focal groups of beaked whales over multiple dives for hours. This was the first BRS project for beaked whales off of an acoustic listening range where there are many hydrophones mounted on the bottom. All our assets were based on the main vessel, and we demonstrated that we could use them in an integrated way to track animals that dive for long periods and cover large areas. A key part of this integration was the development of custom geospatial software for displaying the visual and acoustic animal detection data along with the position of the ship, tag boat, and important ocean features. This capability proved to be essential for real-time decision making in tracking focal animal groups. Lessons learned in developing and refining these capabilities will be imperative in subsequent efforts to track and study beaked whales and other cetaceans.

Additionally, we made several major contributions to understanding the biology and oceanography of three different areas of the western Mediterranean that have not been extensively studied. We made nearly 500 sightings of over 5,000 individual cetaceans from eight species. When and where these animals were seen relative to the physical, biological, and acoustic environments will be very useful in developing and refining predictive habitat models for where marine mammals will occur in the Mediterranean Sea and other areas. Our oceanographic data (see post of 27 August) will be critical in that regard. So to will the large number of passive acoustic measurements made from sonobuoys to measure ambient noise be useful in assessing the extent to which human sounds (e.g., from the dense shipping traffic we saw in many areas) affect the acoustic environment for marine mammals who depend heavily on the use of sound.

Summary information regarding our efforts and accomplishments will be publicly available at a later date. Each of the participating organizations will be provided a link to this information and a subsequent message will be posted to this blog when it is available. We expect that many of our measurements will be used by participating researchers and graduate students in different areas and results will ultimately be presented in scientific meetings and journals.

Thank you to those who have been following the blog for this project. We appreciate the interest in this project. We would like to acknowledge the outstanding crew of the NATO research vessel Alliance that has been our home for the last six weeks. From the captain on down, it is an outstanding platform from which to work with an extremely precise and professional crew. Efforts to better understand the behavior of marine mammals and how sound we make in the oceans can affect and harm them will continue in different ways and places around the world, and it will be served by the efforts of the many dedicated people involved in this project (the team from the second leg appears below).

Friday, September 4, 2009

Found the calm, not the whales

We started the day in the northern part of our area where we have had almost all of our beaked whale sightings, but there was enough swell and wind that we headed south in search of better seas. We found enough lee from the island as we headed down to have workable weather by mid-morning. We covered over 80 miles along and across canyons and seamounts we had previously not searched that looked promising. However, like yesterday we saw almost no marine mammals (and zero beaked whales) despite the favorable conditions. At least in our week's worth of intense visual and acoustic surveys in the Tyrrhenian, marine mammals in the areas we have surveyed seem to be concentrated in particular spots.

Tomorrow will be the last operational day for MED-09. We intend to conduct visual and acoustic surveys, as conditions allow, heading back north and then continue on during the evening back to LaSpezia.

Thursday, September 3, 2009

Where Did They Go?

Today was a bit of a puzzle. Due to heavier winds and swell around our favored locations, we started our day well south of where we have had the most luck in this area. The conditions were better than expected and the heavier seas were further to the north. Consequently, we adapted our search plan to proceed to the area where we found multiple groups yesterday. Conditions ranged from acceptable to excellent throughout the day, though we did get some rolling swell by late afternoon. We covered quite a lot of ocean, moving down the canyon edges around the 1500m contours that haven proven to be good here but, despite having workable conditions from dawn to dusk, we did not have a single beaked whale sighting all day. A few fin whales were seen, along with the occasional group of dolphins, but it was puzzlingly quiet.

The forecast is for marginal conditions over much of our area tomorrow, but we are hoping for better than expected weather again and for the beaked whales to 'pop up like mushrooms' as was described on one of our better days by one of our Italian colleagues.

Wednesday, September 2, 2009

Close again -- then sudden winds

Today we were tantalizingly close again and had an excellent, four-hour focal follow of an adult male and adult female Cuvier's beaked whale (seen here from the tag boat during one of several close approaches). Note the prominent scars marking the male (top), which are thought to result mainly from fights with other males, and the absence of these scars on the female (bottom). The higher winds we had feared from the forecast held off quite a few hours beyond what was predicted and we had outstanding conditions for much of the day. We have quickly figured out where to locate Cuvier's beaked whales in this area (along the 1500m depth contour on the edges of canyons has been the best) and we soon found multiple groups of animals again. We passed up the first group because it was a mother with a small calf, but then found a good candidate group and began to track them.

The image to the left shows a sequence during today's focal follow. It is a bit of a complicated figure (you may need to blow it up a bit) with a lot going on (there was!). But it is a great example of how we can use all our tools to follow animals that dive for over an hour to great depth and then re-spot them at the surface and track them for hours. The sequence began with the ship in the northwest (upper left) corner of the figure and moving along at 6 knots (note the orange dots showing our position being spaced further apart than the rest of track where we were going slower). As we moved to the southeast, the group of two adults was spotted visually during their brief surface intervals. The red symbols with "A" and "B" labels are multiple positions of the same two whales during two surfacings in the same general area. After the animals went down on a deep feeding dive, we passed their spot and dropped a sonobuoy to monitor near that location (small circle with crosshairs along our track). We then moved around the spot monitoring with multiple arrays of listening sensors towed slowly (note our orange position markers being closer together) and began tracking them acoustically. The red circles on our track indicate when the acoustics team heard beaked whale clicks (the bigger the circle the stronger the sounds) and the purple lines show the direction from which they think the sounds are coming. We moved slowly along and kept the group on our port (left) side with very consistent detections - and the acoustics team could even tell that it was two animals. As we approached 30 min of clicking we felt confident enough of where they were and where they would come up that we deployed our tag boat and positioned them accordingly. When the animals re-emerged (positions C1-C5), we had our tag boat about 500m away, despite the fact that the animals were down for 79min and had moved 1500m in directly the opposite direction we had been traveling! As you can see from the increasing number of the "C" sightings in clusters ("E" was another single animal) we moved with the group over multiple other surface intervals between the multiple "shallow" dives (shallow is relative for beaked whales since they can be over 500m) that the animals do before deep feeding dives. The tag boat had several excellent chances, but the animals banked away several times in the last few moments before the tag could be attached. Eventually the group went on another feeding dive and we tracked them again by listening and had a bead on where they would surface. Just at that time, though, the winds tripled very suddenly (we saw the wind line coming) and the tag boat had to be recovered.

We have just a few more days at sea on MED-09 and remain hopeful we can get a few more chances like this and can have the sustained conditions needed to get that last few meters to attach one of the tags and conduct the sound exposure experiment. The weather for tomorrow does not look great, but possibly workable, and we are now fairly confident of where to find beaked whales in the Tyrrhenian Sea when we have the right weather.

Tuesday, September 1, 2009

Flat Seas -- Many Beaked Whales

The sea was glassy calm for several hours this morning - perfect conditions for our visual team. The wind picked up a little bit throughout the day and shifted more to the south where the islands provide us less shelter, but it remained workable throughout the day. We again spotted quite a few fin whales and had the intermittent groups of dolphins, including some that were harassing a group of beaked whales we were following.

With the favorable weather, we found multiple beaked whales groups clustered in a relatively small area. One challenge was that this area was close to the edge of our allowed operational box, which limited our ability to follow several good candidate groups. Another was that many of the groups had small calves, preventing us from close approaches for tag attempts. Overall we had more than 10 different group sightings but are still searching for the right combination of conditions for tagging. Tomorrow looks to be workable but a little less calm than today.