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The End of Leg 2

October 02, 2024

The Gordon Gunter crew wraps up the second leg of the Vessel Survey for Abundance and Distribution on Marine Mammals and Seabirds.

Two dolphins leaping through the air above bright blue water. Pantropical spotted dolphins frolicking through the water. Credit: Terra Mar Applied Sciences/Kate Sutherland (Permit #21938)

Day 28

While it was a beautiful day to be at sea, Tuesday was a variable experience here aboard the Gordon Gunter. Partly cloudy skies with a Beaufort state less than 3 seems to be the norm for now. These excellent visual survey conditions did not translate into many visual sightings for the marine mammal team, who had one distant sighting of unidentified dolphins. The acoustic team had a slightly busier day, with seven detections of “driveby marine mammals.” This included quick and faint unidentified toothed whales, some mysterious whistles, and what sounded like a beaked whale, but will take more analysis to decipher. It was a quiet day for marine mammals out here in the deep.

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A white bird with black wing tips flys downward toward blue ocean water.
A masked booby diving to feed on a school of flying fish. Credit: Terra Mar Applied Sciences/Kate Sutherland

The bird team, however, knocked it out of the park with 12 species recorded over the course of the day! So, the visual team assisted the bird team by letting them know when there were feeding flocks on the horizon. They always give the bird team a heads up, but we like to think today the seabirds helped them have a better day. Feeding flocks of sooty terns—including adults with their attendant young—were the most numerous species seen today. Other tern species encountered were a couple of royals and a sandwich tern. A young (likely around 2 years old) laughing gull came to check out the ship. It stayed with us resting on the bow camera strut until a few others flew by when it decided to join them and left us behind. We had at least one adult barn swallow and a young tree swallow, the first of the survey leg. While we didn't have as many brown boobies as yesterday, we did have a few adults visit and chow down on some flying fish. Late in the afternoon, a young masked booby decided to dine with them as well. Tubenoses today consisted mostly of Audubon's shearwaters, but we also had at least one Cory's shearwater and a couple of band-rumped storm-petrels. And finally, for those of you who have been keeping count, an adult parasitic jaeger flew by in the late afternoon as well (our second of the survey). Phew. It was a busy day above the water out there!

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A white bird with grey wings stands perched on a metal pipe with relaxed, half-open eyes.
Laughing gull, seemingly contemplating life choices. Credit:Terra Mar Applied Sciences/Kate Sutherland

Day 29

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A dolphin swims just below the surface of blue ocean water.
Rough-toothed dolphin. Credit: Terra Mar Applied Sciences/Nicholas Metheny (Permit #21938)

The survey crew was relatively busy while we experienced great conditions for most of the day. There were some patchy squalls in the morning making for some cooler watches outside, but they didn’t interfere with the survey effort and cleared up by afternoon.

Today was off to another noisy start in the shallows for the acoustics team who are getting used to the industrial sounds of the Gulf of Mexico. Amidst the sounds from offshore oil operations and nearby snapping shrimp, the team detected a group of unidentified dolphins. 

The marine mammal team’s day was much more eventful than the previous day, with 31 sightings. They encountered a high diversity of species and only a few unidentified groups. It was very similar to other days when we started in shallow water and saw bottlenose dolphins. After the transition to deep water we saw pantropical spotted dolphinsdwarf or pygmy sperm whalessperm whales, and pilot whales. The highlight of the day was a mixed group of melon-headed whales and rough-toothed dolphins.

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Two grey whales leap just out of the surface of the water.
Melon-headed whales. Credit: NOAA Fisheries/Paula Olson (Permit #21938)

On the bird front, things went swimmingly with nine species sighted today. These include Audubon’s and Cory’s shearwaters, a few band-rumped storm-petrels, a laughing gull, surprisingly few brown boobies, royal and sooty terns, a magnificent frigatebird, and a group of unidentified shorebirds. Other creatures of note were an unidentified sea turtle and a mahi. 

Day 30

Keeping it interesting, today started with a thunderstorm right on our trackline. It dissipated in less than an hour, and we worked the rest of the day in great conditions (again) with an average sea state of less than 2 on the Beaufort scale.

The acoustic team had a busy start to the day with an abundance of sperm whale and dolphin encounters all overlapping each other. However, the highlight of their nine detections was an incredible beaked whale encounter which was likely a Blainville’s! These whales are rare and difficult to observe, particularly due to their long dive times. So, an acoustic detection was a special treat.

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A white and black bird sits on the surface of the ocean.
A lucky shot of the white-tailed tropicbird that quickly flew away. Credit: Terra Mar Applied Sciences/Nicholas Metheny

The bird team had a very slow day. They noted the first bird, an adult barn swallow, at 10:10 a.m. The next bird appeared about 30 minutes later, a very distant young sooty tern. There was an adult white-tailed tropicbird in our path sitting on the water a little before 1:30 p.m. that flushed and then flew away. But it was there, at least! Then there was a very long lull until 6:30 p.m. when a young brown pelican flew in behind the Gordon Gunter. It looked like it wanted to try landing on the ship, but chose instead to settle on the water nearby. To finish off the day, we had three more birds! One young common tern, the first of the leg, and two Cory's shearwaters appeared beside us just before 7 p.m. We recorded six species and seven individual birds for the day. 

The marine mammal team had a flurry of sperm whale sightings to start the day, but then sightings slowed down until around lunchtime, when we spotted a large group of pilot whales. Pilot whales are one of the easier-to-identify species, even at a distance, due to the shape and position of the dorsal fins. While those two features can distinguish them from other species, the males are also physically different compared to females and have very large, broad-based dorsal fins. Finishing out the list of identified animals were pantropical spotted dolphins and pygmy or dwarf sperm whales.

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A grouping of six dark grey dorsal fins stick out of the ocean surface.
A group of short-finned pilot whales. Credit: NOAA Fisheries (Permit #21938)
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Last updated by Southeast Fisheries Science Center on November 05, 2024