Day 20
We began a new week today, and finally experienced something other than blue skies and calm seas. The Gordon Gunter began the day with a thunderstorm hot on her tail, but we managed to stay ahead of the storm and its lightning. The rest of the day was average conditions: partly cloudy, Beaufort sea state 3–4, and swell of 2–3 feet. The marine mammal visual team experienced a more dramatic decline in marine mammal encounters today, with only three sightings of bottlenose and unidentified dolphins. Maybe the marine mammals had a case of the Mondays and called off.
Masked boobies took the weekend off, but they were back this morning with our first sighting at 9:30 a.m. We began the day with five brown boobies, but by the end, just one lone adult female was left perching on our anchor. Before long a masked booby found the ship, and we were treated to the two birds flying in our survey zone. While the smaller brown booby was definitely more acrobatic, the larger masked booby flushed more fish with a single dive.
The morning began with a bang featuring sooty terns, a number of band-rumped storm-petrels, and a single Leach's storm petrel flying along with a group of the former. A sandwich tern flew right over the ship midday, and a distant bridled tern perched on what looked like an old cushion floating by. Sadly, the incredibly ratty-looking young brown booby who has been with us since July 3, who we fondly referred to as “Raggedy Ann/Andy”, jumped ship at about 11:49 a.m. It had exposed primary feather shafts and a dull bill, which could indicate poor health. These characteristics can occur due to inadequate preening (if a bird is away from a roost too long—they can't clean themselves), diseases, poor nutrition, or exposure to toxins. We wished the bird well as it headed over to a large barge.
Day 21
The aftermath of Hurricane Beryl has stirred up most of the Gulf, and we were getting tossed around a bit more than we have experienced thus far. In case you were wondering, a sea state five is pretty rough and makes it difficult to survey, let alone stand up straight. The marine mammal team surveyed in less than desirable conditions, but were still able to find a few groups of bottlenose dolphins. They did have to put the wind dams up on the bridge wings to keep from getting buffeted, as we will be on this course for the next day surveying into the high wind and seas.
The bird visual team saw a few big birds by the ship this morning. The immature masked booby from yesterday hung out with the ship before wandering away. We had a single female adult brown booby that was eventually joined by two more. We also had our greatest number of Cory’s shearwaters so far this trip, along with a few band-rumped storm-petrels, an Audubon’s shearwater, a royal tern, and a sandwich tern.
Tomorrow we will spend the day transiting to the southern end of one of our longest track lines, and then begin our journey northwest in the central Gulf.
Day 22
The survey group spent the day transiting across deep water. The seas and winds laid down overnight, and the teams woke up to calm seas. There was a strong haze for most of the day which made everything appear very monotone, but we still had good luck finding animals.
The marine mammal team had 13 sightings today, five of which were dwarf sperm whales or pygmy sperm whales. Typically, these hard-to-see species are only spotted on super calm days in deep water. This is largely due to their behavior. They rest at the surface for only a few minutes to breathe, then slip underwater again like ninjas. The team also positively identified Risso’s dolphins and a sperm whale.
The bird team started the day with a flock of sooty terns and a couple of Audubon's shearwaters. The booby report for the day consisted of brown and red-footed. Conditions were nice with many mats of seaweed around. It seemed like the perfect opportunity for spotting seabirds since the mats are usually full of tasty prey. In reality, the day was a bit quiet with another light-form red-footed booby and a couple of other tubenose species—band-rumped storm-petrel and Cory's shearwater. The treat today was a flyby prothonotary warbler. For those of you not familiar with this species, it is a small songbird with a gorgeous golden head, back, and underparts. This one zipped by with a few call notes before disappearing behind the ship. We were out in deep water where these birds might not be expected, but they actually migrate across the Gulf of Mexico, so perhaps it was just on a flight path!
The acoustic team was ecstatic to get the array back in the water after a short break to troubleshoot equipment! They kicked off the day with a bang of 15 acoustic detections, including 11 sperm whales and many dolphin species. Perhaps the most exciting thing for the acoustics team was that there was now less background noise from the ship due to reduced cavitation after the propellers were scrubbed during our recent port call. Cavitation noise comes from the formation and then breaking of bubbles that form around a propeller as the ship moves through the water. Reduced cavitation noise increases our chances of detecting marine mammals. It's good to be back!
Day 23
The crew spent the day transiting from deep to shallow water, experiencing relatively calm seas, partly cloudy skies, and lower humidity, which made for pleasant survey conditions. The acoustic team was rewarded with eight acoustic detections today, three of which were probably beaked whale species. Analysts will scrutinize the data more closely when more time allows after the survey to determine the species. The team also detected sperm whales 11,000 meters away. It’s safe to say the acoustic team is happy to be back in deeper waters with the deep-diving species.
The marine mammal visual team encountered a variety of species with 26 total sightings. They started with a sighting of melon-headed whales or pygmy killer whales. There were also a few sperm whale sightings, as well as some pantropical spotted dolphins. One of the deep water sightings was a bit of a conundrum. Thankfully one of the bird observers was at the ready with a camera and captured a few photographs for identification purposes. However, it was difficult to confirm the species, even with photos! The visual team eventually identified it as a beaked whale but was not able to narrow it down to a species. As we moved into shallower water, sighting diversity dropped to bottlenose dolphins and unidentified dolphins that were likely also bottlenose dolphins.
Today was a slow day for the bird team. Few birds were observed, but the birds they did see were exciting ones. They started the day with a small escort of brown boobies before they gradually dwindled away, possibly due to the lack of flying fish. The rest of the bird roster for the day included Audubon’s shearwaters, band-rumped storm-petrels, and a distant questionable storm-petrel that could have been a Leach’s or band-rumped. A laughing gull and several different tern species were encountered including royal terns, sandwich terns, as well as a bridled tern. As we got closer to shore, the team made several sightings of black terns. However, the “Bird of the Day” was the magnificent frigatebird. Frigatebirds are so efficient at soaring that these birds can stay aloft for upwards of two months, sleeping and resting while in flight!