Cephalopod

A two-spot octopus makes beautiful formations in a tank at MBL on August 2.

The California two-spot octopus was anticipating dinner last week. Its tentacles spread out, and the two spots on either side of its body that give the animal its name darkened.

Bret Grasse, the manager of cephalopod operation at the Marine Biological Laboratory where the octopus resides, described this as common behavior when someone approaches the tank.

Mr. Grasse and his team, including fellow aquarist Taylor Sakmar, have been charged by MBL to develop what he described as a “cephalopod empire,” where cephalopod species that include squids, cuttlefish, and octopuses can thrive and reproduce for generations.

Culturing animals in the lab over multiple generations opens up the possibility to use these marine creatures as genetic models, a group that has consisted of non-marine animals such as mice, rats and drosophila [fruit flies].

“It’s taking it to the next sophisticated step for scientific inquiry to use genomic tools,” MBL senior scientist Roger T. Hanlon said.

Dr. Hanlon has been studying cephalopods’ color camouflage capabilities for over 20 years. He has grown species to adulthood in the lab from eggs collected in the wild.

To learn how specific genes target the brain and result in animal activity and behavior, however, animal cultures with known lineages and whose genetic information can be replicated must be developed. That is what Mr. Grasse was brought here to do.

“It’s a piece of a larger puzzle to start generating the new model organisms that will drive research here over the next decade,” MBL scientist Joshua Rosenthal said.

The job of Mr. Grasse and his team is to best mimic the cephalopods’ natural environment, such as seawater composition and temperature, in the aquarium. He looks at data collected by divers and to the animals themselves for clues.

“Part of our job is getting into the head of a cephalopod and to do our best to understand how the animal is feeling, based on their behaviors,” Mr. Grasse said.

Behavior can vary between different species as well as individuals. Another two-spot octopus preferred to be more reclusive, hunkering down in the mug it lives in in its aquarium.

“He’s saying, ‘No photos, please,’ ” Mr. Grasse joked.

His team has to troubleshoot myriad conditions to get them just right for the animals to thrive in the laboratory.

Influences in the wild to be replicated include lunar and light cycles, water flow and the temperature required for an animal to lay eggs and for them to hatch.

“We are doing the job of the mother cuttlefish,” Mr. Grasse said.

Once the eggs hatch, however, there is a whole new challenge, Mr. Sakmar added.

“The animals teach us,” Mr. Sakmar said. “They can always prove us wrong.”

Mr. Grasse and Mr. Sakmar have had success previously at the Monterrey Bay Aquarium, where Mr. Grasse cultured the flamboyant cuttlefish; the pajama squid, named for its stripes, which look like pajamas; and others.

This summer at MBL, Camilla J. Bowin, a student from Bucknell University, is working with Mr. Grasse to study how pajama squid behavior changes from day to night by filming them. So far, she has observed that the tiny squid are more active at night, feeding and mating, and their colors may darken at times.

Cephalopods’ capacity for color change drew Camilla into this area of research.

“I love seeing all the color patterns,” she said. “Every day is different.”

Stimulating natural behavior seen in the wild is also part of making the animals feel at home.

For example, the octopuses receive “games” to exercise their hunting strategies, such as jars with crabs inside, which the octopuses must unscrew to eat, or a shrimp on a stick that they learn to pull off.

“We keep the neurological processes stimulated to mimic natural behavior,” Mr. Grasse said.

Octopuses’ complex nervous systems and behavior are one reason why scientists want to study them. For example, their neural systems are large, with one-third of their neurons in their head and two-thirds extending into the arms.

They essentially have eight spinal cords, said MBL research fellow Eric Edsinger, who was on the project that sequenced the first entire octopus genome for the California two-spot octopus in 2015.

Learning more about the brain-behavior connection in octopuses and other cephalopods is an avenue to explore.

“We’re all waiting for the culture problem to be solved to open the floodgates on what could be done,” Dr. Edsinger said.

Dr. Rosenthal has found that squid, cuttlefish and octopus have a higher rate of RNA editing in their neural tissue compared to a close relative, the more primitive nautilus.

“I don’t know biochemically how it is working,” Dr. Rosenthal said. “But if I could manipulate separate aspects of their genes, I can start answering those questions.”

Other possible research applications being discussed include soft robotic studies, nanorobotics for medical use, and color-changing cosmetics, Mr. Grasse said.

When Mr. Grasse arrived at Monterrey Bay Aquarium more than 10 years ago, he saw a niche to be explored. People there were successfully raising a variety of animals but the cephalopods proved elusive. The egg survival rate was about 20 percent, Mr. Grasse said. During his time there, Mr. Grasse increased that number to 95 percent for some species.

At MBL, he is starting with small and hardy species for the first phase of a three-phase project. So far, the facility is housing about 1,000 individuals. The facility will be a cephalopod source for researchers worldwide.

“We are in the very introductory phase of this but are moving in the right direction,” Mr. Grasse said.

High school student Ella R. W. Spencer is working with the dwarf cuttlefish for a summer project. She lives outside of Philadelphia and has been coming to Woods Hole for the summers and attending the Woods Hole Children’s School of Science since she was 7.

Ella has been feeding cuttlefish probiotics with the bacillus bacteria. The idea is to replace any unwanted bacteria the cuttlefish may be harboring. She first feeds the probiotic to the small shrimp that the cuttlefish eat and has been observing four tanks with about 10 hatchlings in each. Half of the cuttlefish receive the probiotic; the other half do not.

Ella has found that those treated with the probiotics are .07 to .08 grams heavier than those who have not received the probiotics.

The next phase is to do DNA sequencing to learn which type of bacteria live with the treated versus non-treated cuttlefish, she said. Studying the unknowns about cephalopods and their behavior drew her into this research field.

“This is kind of a mystery in a way,” Ella said.

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