Monterey Bay Aquarium Research Institute
2012 midwater ecology cruise

Day 4 – A squid's diet
July 16, 2012

The plan for today was to launch the Midwater Respirometry System (MRS) early in the morning, but the system was not responding properly so we could not launch it. While Kim Reisenbichler and the remotely operated vehicle (ROV) pilots were trying to fix it, we adapted our schedule and decided to recover the camera system we launched yesterday afternoon. This was a short dive from 8:45 a.m. until 10:10 a.m. The retrieval went smoothly and the videos recorded overnight will now be analyzed by Henk-Jan Hoving, a postdoctoral fellow in the Midwater Ecology Lab. Here is how Henk-Jan describes his mission on this cruise:

During this cruise one of my focuses is the feeding ecology of pelagic (open ocean) cephalopods. Information on feeding will tell us where species fit in the pelagic food web of the Monterey Canyon. Also, a critical part in keeping animals alive in the lab is knowing what they feed on. Knowledge of diets will therefore also help us to improve husbandry.

We investigate the feeding ecology of pelagic cephalopods in three ways. One is by looking into the stomach contents of individuals collected with the ROV. The stomach contents of cephalopods are often hardly recognizable, because they use their sharp beak and radula (a minutely toothed ribbon-like anatomical structure) to macerate their food. Ingested food goes via the esophagus, which passes through the brain in cephalopods, to the stomach. I will be using DNA sequences to identify the stomach contents.

Squid tissue samples will be analyzed to obtain a stable isotope signature, allowing us to construct the position of squid in the food web, and to characterize trophic relationships. The analysis of fatty acids in the squid tissue will render more specific information on the group of organisms (e.g. fish or crustaceans) the squid fed on.

Another valuable way to learn more about the diet of pelagic squid is the archived ROV footage in MBARI's Video Annotation and Reference System (VARS) database. Over the years of MBARI's ROV observations, many squid species have been encountered with food in their arms. Yesterday, we observed a Gonatus onyx with a myctophid fish (Stenobrachius leucopsarus) in its arms. Almost all knowledge that is available in the scientific literature on squid's diets is based on trawl-captured individuals. The stomach contents of trawl-captured squid may be biased by so-called net feeding. Induced by stress, trawl-captured squid start eating any organism that is within reach, biasing diet studies. The ROV records of squid with captured prey provide a unique natural insight into the squid's diet.

—Henk-Jan Hoving

Gonatus squid feeding on a myctophid fish.

The second dive of the day started at 11:05 a.m. We collected different animals including several squid (Taonius and Chiroteuthis calyx). We also collected some Sergestes similis shrimp that will be used by Kim Reisenbichler for respirometry experiments.

Cockatoo squid. (Taonius)

Kim managed to fix the MRS that was then reconnected to the ROV in the evening. Everything is now ready for tomorrow morning!

—Geraldine Fauville

Previous log Next log


Day 6 Day 6
July 18, 2012
Seeing in the dark

Day 5 Day 5
July 17, 2012
Important observations

Day 4 Day 4
July 16, 2012
A squid's diet

Day 3 Day 3
July 15, 2012
Science never sleeps

Day 2 Day 2
July 14, 2012
Searching the deep sea

day one Day 1
July 13, 2012
Our first dive


R/V Western Flyer

The R/V Western Flyer is a small water-plane area twin hull (SWATH) oceanographic research vessel measuring 35.6 meters long and 16.2 meters wide. It was designed and constructed for MBARI to serve as the support vessel for ROV operations. Her missions include the Monterey Bay as well as extended cruises to Hawaii, Gulf of California, and the Pacific Northwest.

ROV Doc Ricketts

ROV Doc Ricketts is MBARI's next generation ROV. The system breaks new ground in providing an integrated unmanned submersible research platform, with many powerful features providing efficient, reliable and precise sampling and data collection in a wide range of missions.

Midwater respirometry system (MRS)

The MRS conducts oxygen consumption rate measurements in situ gauging the metabolism of animals without subjecting them to the stresses of transport to the surface. MRS has been modified to operate in deeper water with an expanded capacity, enabling respiration studies on animals that live deeper than 1,250 meters.

Detritus sampler

Detritus samplers are large plexiglass containers with lids that can be controlled by the pilot of the ROV and gently closed once an organism is trapped inside.


The CTDO is mounted on the ROV and takes in situ measurements of environmental parameters such as conductivity, temperature, depth, and oxygen concentration.

High frequency suction sampler

This sampler acts like a vacuum cleaner sucking up samples and depositing them into one of the 12 buckets.

 Research Team

bruce robison Bruce Robison
Senior Scientist, MBARI

Bruce Robison's research is focused on the biology and ecology of deep-sea animals, particularly those that inhabit the oceanic water column. He pioneered the use of undersea vehicles for these studies and he led the first team of scientists trained as research submersible pilots. At MBARI, his research group has focused on the development of remotely operated vehicles as platforms for deep-sea science.

kim reisenbichler Kim Reisenbichler
Senior Research Technician, MBARI

Kim's general area of interest is the study of midwater and deep sea animals. He has developed many tools and techniques to observe, manipulate, and collect these organisms, and to maintain the animals in the lab.

rob sherlock Rob Sherlock
Senior Research Technician, MBARI

Rob is interested in the ecology of midwater invertebrates. He has worked in the Robison lab and been involved with the Midwater Time Series since he came to MBARI in 1996, identifying and quantifying mesopelagic animals and the changes in that community over time, depth and relative to other physical factors. He is looking forward to more sea-time this year than last!

kris walz Kris Walz
Research Assistant, MBARI

Kris works with the Midwater Ecology group, analyzing ROV video transects between 50 and 1,000 meters in depth to identify biological organisms from all taxonomic levels, most of which spend their entire lives in the oceanic water column. Kris started working at MBARI in 1996 after finishing her Master's at UC Santa Cruz. She's looking forward to returning to sea this month to collect video transects and search for deep-sea lobster larvae from the family Polychelidae.

susan von thun Susan von Thun
Research Technician, MBARI

Susan works in the MBARI video lab, where her primary responsibility is to watch video taken with MBARI's remotely operated vehicles (ROVs) and make observations about the organisms, behaviors, equipment, and geological features that she sees. While annotating video, she's become adept at identifying numerous deep-sea organisms, specializing in midwater organisms. She works closely with the midwater ecology group and the bioluminescence lab to expand her knowledge of the fish, jellies, cephalopods, and other groups in the midwater.

henk-jan hoving Henk-Jan Hoving
Postdoctoral Fellow, MBARI

Henk-Jan is a postdoc in the Midwater Ecology Group of Bruce Robison, Ph.D., investigating the life history strategies of pelagic cephalopods. Cephalopods have one reproductive cycle after which they die. Henk-Jan is interested in how long deep-sea cephalopods live, and how different species shape their reproductive strategies to optimize their single reproductive event.

Karen Osborn Karen Osborn
Smithsonian Institution

After completing her Ph.D. at University of California, Berkeley and MBARI, then a postdoc at Scripps Institution of Oceanography, Karen received a scientist position at the Smithsonian National Museum of Natural History. Her research focuses on the evolution of pelagic invertebrates, primarily polychaete worms and isopod crustaceans.

Bret Grasse
Monterey Bay Aquarium

Bret is an aquarist at Monterey Bay Aquarium where his job is to highlight and display a wide variety of marine organisms by providing the best possible conditions for each individual in captivity. Bret specializes in tropical systems and cephalopods.

Geraldine Fauville Geraldine Fauville
Summer Intern, MBARI

Geraldine has a master's degree in marine biology and is currently working toward a master's in education, communication and new technologies at the University of Gothenburg. She is a summer intern with MBARI's ITD division, investigating the potential for outreach and communication that social media holds.