A stretch of exceptionally calm seas off of the North Carolina coast made for two very productive field days for some of the Read Lab researchers and students.
On Friday morning, 4 October, we deployed five marine autonomous recording units (MARU), or pop-up buoys, across the continental shelf off of the Outer Banks as part of a collaborative project with NOAA’s Northeast Fisheries Science Center and Cornell’s Bioacoustics Research Program. The objective of this project is to investigate the timing of right whale migration through the Mid-Atlantic region, as well as the relative distance from shore and acoustic behavior of migrating whales. See Joy Stanistreet’s recent post for more information about this project.
Following the buoy deployment, we had several hours left in the day to conduct marine mammal surveys as part of our ongoing survey effort for the Navy. We encountered eight groups of offshore bottlenose dolphins, but even more exciting was the sighting of a fin whale, from which we were able to obtain photo-identification images and a biopsy sample (SEFSC Permit 779-1633) which will provide insights into the population of fin whales that visit this area. This is the fourth fin whale we’ve encountered and the third biopsy sample we’ve obtained from fin whales along the shelf break in the last two months. This particular fin whale had a very distinctive dorsal fin, which will help us identify the individual and possibly match it to previous sightings from the Atlantic.
On Saturday, 5 October, we headed out to work on another ongoing project that is focused on locating deep-diving marine mammals, such as sperm whales and beaked whales, while obtaining biopsy samples from them. Deep-diving mammals spend a lot of time (up to an hour) below the surface, where they feed on deep-water prey such as squid; therefore it can be rather challenging to locate these animals from a vessel. We’ve had success locating sperm whales acoustically using a directional hydrophone, and have even collected biopsy samples from them, but so far, we have had less luck encountering beaked whales this year. Fortunately for us, the flat-calm seas on Saturday were conducive for sighting the elusive creatures, and when we encountered a group of three beaked whales in the morning, we were pleasantly surprised. Past attempts at approaching beaked whales in this area have proved challenging, so we knew we may only have one chance to get close enough to the group to obtain good photo-id images and biopsy samples. The group consisted of a heavily scarred male and a mom/calf pair. The animals were consistently diving for 10-15 minutes between surfacings and were traveling in a predictable direction, enabling us to stay with them long enough to make an approach. On the third surfacing of the group, we obtained a partial sample from the adult female, and a full sample from the male. These are the first genetic samples of beaked whales that we have been able to collect.
A total sightings list for the day included an additional beaked whale sighting, for a total of seven individuals, in addition to nine pilot whale sightings, six bottlenose dolphin sightings, and one group of Risso’s dolphins, from which we collected two biopsy samples.
Next year, the Deep Diver project will be focusing on attaching tags to sperm whales and beaked whales to record their dive behavior.