Swimming with the sea lions near Bird Island

On Thursday (5/15) we split the group up and took two boats to Bird Island (Isla San Jorge). It's approximately 28 miles from the coast of Puerto Peñasco, which meant an hour and a half long boat ride for us. Our main goal of the day was to swim with the sea lions and complete a census for CEDO. We tried on our wetsuits (provided by CEDO) the day before, which was quite a harrowing task. Most of us had never tried on a wetsuit, so we were very surprised to find out how difficult they are to put on. (And take off) We felt like arthropods molting when it was time to take off our wetsuits. Once we got close to bird island, we understood where the name comes from. The island was flocked with birds, mainly the brown-footed and blue-footed boobies. We also saw some seagulls, cormorants, red-billed tropic birds, and pelicans. Once we arrived at the island and anchored our boats, we saw the hundreds of sea lions that inhabit the island and the surrounding waters. Sea lions are in the Phylum Chordata, along with all other vertebrates. (Including humans!). The 5 defining characteristics of the Phylum Chordata are 1. A notochord 2. A dorsal hollow nerve chord 3. Pharyngeal slits (gills) 4. Thyroid gland 5. Post-anal tail. Chordates must possess all of these traits at some point, but some are only in the embryonic stage. This means that as humans, we possess gills and tails in the womb. Crazy! The sea lions at bird island were incredibly excited to see us, and were very friendly even in such close proximity. In the attached gif, you can see the juveniles swimming around me. (It wouldn't let me attach the video so I had to turn it into a gif lol) They were so curious and loved interacting with all of us. After we were done diving and snorkeling we got back on the boats to conduct the sea lion census for CEDO. We drove very slowly around the island and Elizabeth, Elba, and I counted all of the males that we could identify while Valentina and Isabella counted the females. The mature males are extremely easy to identify because of their pronounced primordial crest and extremely large size in comparison to the females. The juvenile males have a minimally pronounced primordial crest and are not yet considerably larger than the females, so they are hard to differentiate from far away. I had sent my mom the video of the sea lions swimming with me the other day and she said "Seals?!?!?!?!😍😍😍." Very funny but this is a great chance to discuss the difference between sea lions and true seals! They are both in the Phylum Chordata and Class Pinnipedia, so they are very closely related. The family Otariidae (eared seals) contains sea lions and fur seals, while the family phocidae (earless seals) contains all of the true seals. Sea lions and fur seals can be distinguished by their external ears, longer necks, and anterior flippers that help them sit up or walk on land. True seals have no external ear flap, shorter necks, and cannot rotate their anterior flippers for walking so they resort to bouncing on their bellies as a form of locomotion on land. Those are the main differences, and the most helpful ways to visually distinguish them quickly. The photo I attached has even more information :) Hope that makes sense mom!! 

-Audrey Wain







Comments

Post a Comment

Popular posts from this blog

Tide pooling and Phyla Fun

Image
Yesterday we all headed down to the rocky intertidal shore at Vina Del Mar to go tide pooling. The rocks were massive and considerably difficult to traverse. I think everybody fell at least once. No major injuries though! We worked our way to the rocks just in front of the water first, in order to get a chance of seeing that area before the tide started to come in and cover it up. We found a wide array of organisms, including swimming crabs, porcelain crabs, hermit crabs, turban snails, blennies, brittle stars, sunstars, sea urchins, two-spotted octopus, sea urchins, sea cucumbers, anemones, isopods, chiton, etc. My personal favorites were the brittle stars and the marine isopod. Brittle stars are in the Phylum Echinodermata, which also includes sea stars, sea urchins, sea cucumbers, and sand dollars. Some characteristics of Echinoderms are their radial symmetry (except in larval stages), water vascular system, and calcium carbonate endoskeleton. This brittle star in particular was a s...
Read more

First Day!

Image
Our journey began yesterday morning when we loaded into the vans and took off from the MCC Red Mountain campus.  We arrived at CEDO yesterday afternoon and settled into our new home for the week. Later that evening, we ventured downtown and had dinner at a restaurant with a scenic view.  Some of the students went down to the shore to do some night tidepooling and saw a few cool organisms. The real fun began this morning, when we went out for our group first tidepooling excursion just a short walk away from CEDO. I'll let the students share what we found 😀. We are planning to finish up our lecture material today so that we can focus on field work the rest of the week--we have a full schedule including tidepooling at rocky shore and sandy habitats, kayaking an estuary, and snorkeling with sea lions! I'm looking forward to the fun-filled week ahead! -Whitney
Read more