On the third day of the Brad Sneeden Marine Science Academy, the students had three activities that took them all over the Sound just off Beaufort, NC. My group of students started off on Piver’s Island at the Duke Marine lab, then boarded the Susan B. Hudson research vessel to go over to Shackleford Island. At Shackleford, we met up with Dr. Sue Stuska who took us to view some of the island’s wild horses. Finally, we reboarded the Susan Hudson for a dredge/trawling activity in the sound.
Duke Marine Lab
At the Duke Marine Lab, students met with one of the graduate students in marine biology. She led us through a discussion of the characteristics of marine mammals, starting off with whales. The students were given the task of pretending to be each of the three types of baleen whales: strainers, gulpers, and bubblers. The students seemed to have the most fun being bubblers. Here’s a picture of four students working together as bubblers using oregano to represent fish, straws to represent the whales expelling bubbles from their blow holes, allowing them to create a “bait ball” of fish.
And here’s a video from Nature’s Great Events of a humpback whale swallowing a bait ball created by dolphins:
From there, the students got a chance to try out Adobe Audition to view and listen to recordings of dolphin sounds. Students worked to isolate the “voices” of particular dolphins by listening and viewing the waveform of the audio files.
Shackleford Island Horses
After boarding the Susan B. Hudson and taking the short trip over to Shackleford, the students had a walking lunch on the way to view some of the horses. Shackleford has 121 wild horses that have been here in North Carolina for centuries. Legend has it that they swam/washed ashore from sinking ships sailing from Europe, however the likelihood of those ships carrying both male and female horses is slim. The horses are genetically linked to Spanish horses, but there is no certain point or time of origin for these horses in North Carolina.
This group of horses walked up to us and a couple of them were less than 5 feet away from members of our group. Dr. Stuska assured us that to these horses humans are generally little more than part of the landscape, like trees or bushes. They do not as of yet look for human food as they have an abundance of food on the islands. They also only become wary of humans if we come too close or appear to surround them.
While we watched, Dr. Stuska discussed a couple of different methods for biological sampling by having some students continuously looking for behavior changes, while others recorded behaviors every 30 seconds. The students were testing the hypothesis that mares graze more often than stallions. Though we only were able to watch for about 4 to 5 minutes, the hypothesis was supported by the data collected. Dr. Stuska confirmed the results, but added that stallions appear to eat faster than mares despite the decreased grazing time.
After the few minutes of data collection, we moved further down the island to observer another harem. This one had eight total horses including a couple of foals. One of the females was suspected to be pregnant and another of the rangers was attempting to collect a dung sample to confirm their suspicions. We spent about another half hour observing the horses and then headed back to board the Susan Hudson for our trawling activity.
On Board the Susan Hudson
The winds were too strong for us to take the Susan Hudson out oceanside, so we stayed in the sound for our dredge and trawling activities. After a few minutes on the water, we dropped the dredge bucket to see what sorts of organisms we could collect off the bottom of the Sound. Our dredge returned an abundance of sea urchins and lots of empty oyster shells. Digging around we found a few other interesting critters. There were some small crabs, a couple of hermit crabs, live scallops, and a couple of unknown gastropods. The students were most interested in the sea urchins and a brittle star that was found after the initial search.
After the dredge, we tossed out the trawl net to see what we could find higher in the water column. Hauling in the net returned a small number of fish, but some with interesting differences. We caught a couple of spot, a small flounder, and a lizardfish. Students took time to look at the adaptations that allowed each fish to fill its’ particular ecological niche. Earlier in the day, the students caught a flounder that was young enough to still have an eye on each side of its head, but unfortunately had to toss it back before our group boarded the ship.
All in all, Day 3 was a wonderful day, with cooler temperatures, no rain, and some excellent science activities enjoyed by all!!