The humpback whales currently migrating past Raoul are travelling south from their breeding grounds in the tropical Pacific. This means that there are a lot of mother-calf pairs travelling together. Yesterday our expedition team was treated to the sight of a young humpback calf breaching repeatedly alongside its mother as they slowly moved out of the bay. We followed the pair for about an hour, and at times it seemed like the calf was spending more time in the air than the water. Humpback calves typically weigh 1-2 tonnes when they are born and gain up to 50 kg per day when suckling from their mothers. This calf was relatively small (a late-season birth) but it had far more energy than it knew what to do with. Watching the calves play and associate with one another has been one of the unexpected joys of this trip.
The satellite tags used for this study are implanted in the whales using a compressed air ‘gun’ fired from the bow of one of our small tenders. Yesterday a shot arced over the back of an adult humpback and landed in the drink as one of the tag attachments became loose in transit. A few days ago we lost a tag for the first time; our gift to Tangaroa. Fortunately yesterday’s tag landed near to shore in only 20 metres of water, and our dive team – Richie, Steve and Braveheart’s culinary genius Charlie – was able to descend and carry out an emergency retrieval. Each of these satellite tags is worth about $3500 so the scuba squad has well and truly earned their beer this week!
Over the past ten days a few of the team have spotted an occasional immense blow of water on the horizon, suspiciously straight and far taller than those made by the humpbacks. This morning our suspicions were confirmed as we watched the pale silhouette of a pygmy blue whale pass slowly underneath our boat. Although not fully grown, this whale was already much larger than the humpback whales we are here to study. It seems that every day the waters around this island show us something new.
Current totals: 20 satellite tags deployed, 79 tissue samples collected, 80+ fluke photo-identifications. One and a half days of fieldwork to go!