From the Ledge: Saturday, May 28

This is the second in my series of reports from this year’s expedition to Cashes Ledge with Brian Skerry and Brown University biologist Jon Witman. Follow the expedition on Twitter for regular updates!

What a special place to be. The fog cleared yesterday, and after our own dinner, as the sun set behind the clouds, we sat on the bow watching whales lunge feed on schools of herring. When the herring balls, moving as one unit, came close enough to the ship, you could see each individual fish swimming just below the surface. At night, the sky was filled with stars, as you would expect I guess being 100 miles from land.

Strong winds and larger waves had been predicted for today, but we’ve been lucky to have calm seas and a bright, warm sun.

The team reported that the visibility was better than yesterday, giving a milky blue look underwater. One diver said the absence of current made it feel like “hydrotherapy” – even though the water was still only 49°F.

On the first dive of the day, Dr. Jon Witman placed two GoPro cameras on Ammen Rock, one on top of a knoll and the other in a gulley, to take video of the fish swimming by. He collected the cameras on the second dive and will bring them back to his lab for analysis.

Brian Skerry described to us the scenery that he tried to capture with his photographs: gold kelp with a soft amber-colored algae bottom, a wolfish slithering into the kelp just near the bottom of the anchor line, and a photo-shy red cod.

Just before lunch, Dr. Witman gave the group a science lesson about the internal waves found at Cashes Ledge, which are what make the ecosystem so productive. The waves, which give the surface water a slick appearance, create what he calls a “food elevator,” delivering layers of concentrated phytoplankton to the deeper waters multiple times a day. Seabirds feed and minke whales dive into the layers.

The most exciting part of the day was when two minke whales swam through the dive site just as the team was surfacing! They then stayed in the area to feed on the plentiful plankton at Ammen Rock.

It’s late in the afternoon, but the camera team is about to head out for their third dive. Dr. Witman has collected his data for this site and will dive again tomorrow.

Dive 1: 50 minutes, average depth 32 feet, max depth 43 feet
Dive 2: 48 minutes, average depth 38 feet, max depth 51 feet
Water temperature: 49°F