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, 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.

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.

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