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Through the night we travelled towards the eastern boundary of our study area. Few calls were heard despite regularly deploying sonobuoys. Mindful that poor weather was forecast we decided to meander back towards Portland during daylight hours and hopefully find a few pods of whales along the way. During the morning a few gremlins tested the acoustics team but they soon identified the issues and resurrected our systems. When whales were detected they were in a similar location to where we had sighted whales the day before. Using our acoustic bearings we found whales but the conditions were poor with a lot of slop, low light and the whales surfacing unpredictably – together this made photo-identification very difficult. Soon we heard calls from another group and we decided to move on. It seems we had come across another patch of sea favoured by these whales as we quickly sighted more whales, however, the acousticians were not convinced they were ‘their whales’ - the whale(s) they had heard singing. As the project is all about how well we can use acoustic information to lead a ship to singing whales we simply noted these sightings and continued on our bearing. Soon we found new whales and the acousticians were satisfied this time - these blue whales were on the right bearing and distance from our sonobuoys. We then moved to position so the vessel could receive information from two of our buoys simultaneously and we sat and monitored the movement of these whales for several hours. The repeated cross bearings allowed us to track the movement of the whales and after we thought they had moved a reasonable distance we went to their new location to confirm we had been tracking the same whales. Again photo-identification was difficult because the conditions had continued to deteriorate through the day. When blue whales disappear in the swell we know it’s time for us to head home! We are now steaming west and we will try to detect whales as we travel but the team is getting tired after long hours of intense concentration so we may simply shut down operations and spend at least the next couple of blowy days at the wharf.
REGARDS: Mike
Map
A map showing Australia and Antarctica. The map shows the journey of one voyage that has occured in the season, with each route highlighted in a distinct colour.