Monterey Bay Aquarium Research Institute
2013 midwater ecology cruise

Day 5 – What's for dinner?
November 11, 2013

Over the last few days we’ve shared photos and stories of some of the amazing deep-sea animals we’ve seen this week. However, I’m going to be honest—it’s not all giant jellyfish and mystery molluscs down there. We spend a lot of time looking at marine snow and hoping to come across something cool. In fact, over the course of my career working in MBARI’s video lab, I’ve watched thousands of hours of video and made over a million observations of animals in our video annotation database (VARS), but most of those observations are of tiny things flying by the screen. That data has incredible value, giving us depth and geographical distributions. However, I will admit, it’s much more exciting to see interesting behaviors and new animals. Those exciting observations are like a grain of sand on a beach, a rare glimpse of a world that humans could never view without submersibles, and the high-definition cameras make it all the better.

Today was a day that epitomizes this idea. We spent many hours looking at not much more than marine snow, but we were rewarded for our patience. It is always interesting to be able to see deep-sea animals eating their prey. Some of the feeding interactions we saw today included jellyfish eating comb jellies, jellyfish eating other jellyfish, amphipods eating jellyfish, squid eating squid, squid eating fish, just to name a few.

Left, The jellyfish Aegina sp. holding on to the comb jelly Lampocteis cruentiventer in hopes of eating it later. Right, Aegina sp. eating another Aegina sp.
Left, One squid (Gonatus sp.) eating another Gonatus sp. The red one is winning and the white one losing. Right, Gonatus sp. eating a fish, most likely a lanternfish. You can see the white tail of the fish peeking out of the squid’s arm tips.

Seeing these feeding interactions with the ROV is invaluable. After we trawl for animals by dragging a net through the water, we can dissect animals to see their gut contents to know what they ate, but that gives us no insight into how animals behave while feeding and how predators and prey interact. Today, we saw one of the most spectacular feeding events that we’ve quite possibly ever seen with MBARI’s ROVs. ROV pilot Knute Brekke spotted a squid eating something. We stopped to look—well, first you have to see the images to believe me.

A relatively small squid, Gonatus onyx, attacking an owlfish, Bathylagus sp. This squid is probably four to five inches long, while the owlfish is about 10-12 inches long.

With the expert ROV flying of Knute and Mark Talkovic, we watched this fight for just under an hour. The squid, although much smaller than the owlfish, clearly had the upper hand. The squid was tightly holding the fish over the gill slits, possibly in attempts to suffocate the fish. It was also rotating the fish in its grasp, biting a groove all the way around, behind the head. The fish would twitch occasionally, but was clearly losing the battle. Stay tuned for a YouTube video featuring this epic battle between invertebrate and vertebrate. We all know which marine organisms are way cooler, and now we have proof of how much more ferocious they are.

— Susan von Thun

Previous log Next log


Day 7 Day 7
November 13, 2013
Last day

Day 6 Day 6
November 12, 2013
Stayin' alive!

Day 5 Day 5
November 11, 2013
What's for dinner?

Day 4 Day 4
November 10, 2013
On the hunt for deep-living animals

Day 3 Day 3
November 9, 2013
Deep midwater respirometry system (MRS) deployment

Day 2 Day 2
November 8, 2013
Expansion of the oxygen minimum zone

whale's fluke Day 1
November 7, 2013
Why study the midwater and what the heck is OMZ?


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
Research Specialist, 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 and depth and relative to other physical factors.

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. Kris started working at MBARI in 1996 after finishing her master's degree at University of California, Santa Cruz. She's looking forward to going to sea this month to collect video transects and to search for deep-sea lobster larvae from the family Polychelidae.

susan von thun Susan von Thun
Senior 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.

Stephanie Bush
Postdoctoral Fellow, MBARI

Stephanie will be collecting squids and octopuses for the Monterey Bay Aquarium's upcoming cephalopod exhibit "Tentacles". She will also continue her research on deep-sea cephalopod behavior and population connectivity in planktonic animals.

goetz Freya Goetz
Museum Technician, Smithsonian Institution

Freya is collecting hyperiid amphipods, polychaetes and sampling of other animals for Karen Osborn at the Smithsonian Institution's National Museum of Natural History. The animals collected will be for a variety of projects including the study of amphipod eye structure, animal microbiomes and population genetics.

burford Ben Burford
Research Assistant

Ben's undergraduate degree encompassed terrestrial and aquatic zoology, ecology, and botany. He has become fascinated with and engrossed in the study of deep-sea ecology and behavior. This focus comes after recently completing an internship in the Robison Midwater Ecology Lab at MBARI where he examined the behavior of the deep-sea cephalopod, Chiroteuthis calyx.