Suzanne Acord: Cetaceans Are Among Us! March 26, 2014

NOAA Teacher at Sea
Suzanne Acord
Aboard NOAA Ship Oscar Elton Sette
March 17 – 28, 2014

Mission: Kona Area Integrated Ecosystems Assessment Project
Geographical area of cruise: Hawaiian Islands
Date: March 26, 2014

Weather Data from the Bridge at 13:00
Wind: 6 knots
Visibility: 10+ nautical miles
Weather: Hazy
Depth in fathoms: 2,473
Depth in feet: 14,838
Temperature: 26.0˚ Celsius

Science and Technology Log

Cetaceans Are Among Us!

Our Marine Mammal Observation (MMO) crew was in for a treat today. Just after lunch, we spot a pod of sperm whales. We spotted them off the port side, off the starboard side, and eventually off the bow of the Sette. We frequently see Humpback whales in Hawaii, but sperm whales often evade us. Sperm whales can dive down to extreme depths and they feed on squid. These same squid feed on the micronekton that we are observing during the cruise. Sperm whales are the largest of the toothed whales. Their enormous size is obvious when they slap the ocean with their giant tails. Another unique characteristic of the sperm whale is their blow hole, which sits to the left rather than on top of the head. This feature allows our MMO team to easily identify them.

Our MMO lead, Ali Bayless, determines that we should take the small boat out for a closer examination of the pod. Within minutes, the small boat and three scientists are in the water following the pod. We think that a calf (baby) is accompanying two of the adult whales. Throughout the next few hours, our small boat is in constant contact with our flying bridge, bridge, and acoustics team to determine the location of the whales. We keep a safe distance from all of the whales, but especially the calf. While on the small boat, MMO scientists also identify spotted and spinner dolphins. We are essentially surrounded by cetaceans. The small boat is just one of the many tools we use to determine what inhabits the ocean. We also use an EK60 sonar, our Remotely Operated Vehicle, our hydrophone, and sonar buoys.

Our acoustics lead, Adrienne Copeland, is especially excited about our sperm whale sightings. Adrienne is a graduate student in zoology at the University of Hawaii. She earned her Bachelor’s of Science in biology with a minor in math and a certificate in mathematical biology from Washington State University. She has served on the Sette four times and is currently serving her third stint as acoustics lead. This is a testament to her expertise and the respect she has earned within the field.

Adrienne Copeland monitors our acoustics station during our 2014 IEA cruise.

Adrienne Copeland monitors our acoustics station during our 2014 IEA cruise.

Adrienne Copeland studies the foraging behavior of deep diving odontocetes (toothed whales). She shares that some deep diving odontocetes have been known to dive more than 1000 meters. Short finned pilot whales have been observed diving 600-800 meters during the day. During night dives we know they forage at shallower depths on squid and fish. How do we know how deep these mammals dive? Tags placed on these mammals send depth data to scientists. How do we know what marine mammals eat? Scientists are able to examine the stomach contents of mammals who are stranded. Interestingly, scientists know that sperm whales feed on histioteuthis (a type of squid) in the Gulf of Mexico. A 2014 IEA trawl operation brought in one of these squid, which the sperm whales may be targeting for food.

Notice the distinct blue and gray lines toward the top of the screen. These are the think layers of micronekton that migrated up at sunset. The number at the top of the screen expresses the depth to the sea floor.

Notice the distinct blue and gray lines toward the top of the screen. These are the thick layers of micronekton that migrated up at sunset. The number at the top of the screen expresses the depth to the sea floor.

Examine the acoustics screen to the left. Can you identify the gray and blue lines toward the top of the screen? These scattering layers of micronekton ascend and descend depending on the sun. Adrienne is interested in learning how these scattering layers change during whale foraging. Our EK60, Remotely Operated Vehicle, and highly prescribed trawling all allow us to gain a better understanding of the contents of the scattering layers. A greater understanding of whale and micronekton behavior has the potential to lead to more effective conservation practices. All marine mammals are currently protected under the Marine Mammal Protection Act. Sperm Whales are protected under the Endangered Species Act.

Interesting fact from Adrienne: Historical scientists could indeed see the scattering layers on their sonar, but they thought the layers were the ocean floor. Now we know they represent the layers of micronekton, but old habits die hard, so the science community sometimes refers to them as false bottoms.

Live Feed at 543 Meters! 

The ROV prior to deployment.

The ROV prior to deployment.

Our Remotely Operated Vehicle (ROV) deployment is a success! We deploy the ROV thanks to an effective team of crew members, scientists, and NOAA Corps officers working together. ROV deployment takes place on the port side of the ship. We take our ROV down to approximately 543 meters. We are able to survey with the ROV for a solid five hours. A plethora of team members stop by the eLab to “ooh” and “ahh” over the live feed from the ROV. Excitingly, the ROV is deployed prior to the vertical migration of the micronekton and during the early stages of the ascent. The timing is impeccable because our acoustics team is very curious to know which animals contribute to the thick blue and gray lines on our acoustics screens during the migration. In the ROV live feed, the micronekton are certainly visible. However, because the animals are so small, they almost look like snow falling in front of the ROV camera. Periodically, we can identify squid, larger fish, and jellies.

Did you Know? 

Kevin Lewand of the Monterey Bay Aquarium constructs a hyperbaric chamber for marine life on board the Sette.

Kevin Lewand of the Monterey Bay Aquarium constructs a hyperbaric chamber for marine life.

Mini hyperbaric chambers can be used to save fish who are brought to the surface from deep depths. These chambers are often used to assist humans who scuba dive at depths too deep for humans or who do not effectively depressurize when returning to the surface after SCUBA diving. The pressure of the deep water can be life threatening for humans. Too much pressure or too little pressure in the water can be life threatening for marine life, too. Marine life collector, Kevin Lewand, constructed a marine life hyperbaric chamber aboard the Sette. He learned this skill from his mentor. Be sure to say Aloha to him when you visit the Monterey Bay Aquarium in Monterey, California.

 

 

 

 

Personal Log

Daily Life Aboard the Sette

There is never a dull moment on the ship. Tonight we have ROV operations, squid jigging, acoustics monitoring, and a CTD deployment. We of course can’t forget the fact that our bridge officers are constantly ensuring we are en route to our next location. Tonight’s science operations will most likely end around 05:00 (tomorrow). Crew members work 24/7 and are usually willing to share their expertise or a good story. If they are busy completing a task, they always offer to chat at another time. I find that the more I learn about the Sette, the more I yearn to know. The end of the cruise is just two days away. I am surprised by how quickly my time aboard the ship has passed. I look forward to sharing my new knowledge and amazing experiences with my students and colleagues. I have a strong feeling that my students will want to ask as many questions as I have asked the Sette crew. Aloha and mahalo to the Sette.