Weird Lobster Makes Hard Science Harder

Written by on June 1, 2015 in Marine Life

Wit and persistence pay off in scientist’s plight to study the Mediterranean slipper lobster

By Evan Lubofsky

Very rarely do scientific field studies go off without a hitch. Unexpected situations come up, and it takes patience, wits and improv skills to get around them.

But some scientists can’t seem to catch a break.

Jason at Akko. Photo credit: Rebecca Kibler.

Jason at Akko. Photo credit: Rebecca Kibler.

Take Eastern Connecticut State University ecology professor Jason Goldstein. If he knew what he was in for before spending a year studying the behavior of one of the planet’s most elusive and least-studied lobsters, the Mediterranean slipper lobster, he might have called the whole thing off.

Goldstein’s research – which took him from New England to the shores of Northern Israel 6,000 miles away – got off to a rocky start with what would seem like a simple task: rounding up a tank full of lobsters to study.

“To gather up a bunch of New England lobsters for a study, no sweat,” said Goldstein. “Just toss a trap in the water overnight and in the morning you’ll have your study sample. But try collecting a dozen or so Mediterranean slipper lobsters and you’re in for a rude awakening.”

Goldstein, along with slipper lobster expert and colleague Professor Ehud Spanier from the University of Haifa in Israel, had to gear up and SCUBA down to seek out the slippers – nicknamed “sea crickets” in Hebrew for their long abdomens and insect-like, bulging eyes.

While navigating the cavernous landscape of Israel’s Achziv Marine Reserve in Rosh Hanikra, the scientists found themselves in a game of hide-and-seek. The elusive lobsters hid in benthic depressions and crevices, their mottled, rock-colored shells rendering them indistinguishable from the surroundings.

If spotting a slipper was half the battle, catching one was the other. These lobsters knew a thing or two about protection. Some of them buried their flat bodies in the sand when approached, while others clung onto rocks like Crazy Glue.

“One of the slippers extruded such a clinging force, we had to use a crowbar to pry it off of a rock,” Goldstein said. “That was pretty intense.”

Lab patience

Lobster Underwater. Photo credit: Rebecca Kibler.

Lobster Underwater. Photo credit: Rebecca Kibler.

In the lab, the slipper lobsters caused more headaches. They are picky eaters and feed on nothing but live bivalves, forcing Goldstein to regularly stock up on fresh mussels and limpets.

Then, there was the process of outfitting the slippers with activity sensors to track their movements. Unlike many lobster species, slipper lobsters are clawless. And without claws, there wasn’t much to attach the sensors to. So Goldstein improvised and created a specialized sensor harness the slippers could wear on their thick, tank-like backs.

“We built an epoxy cradle on the back of each lobster and cable-tied the harness onto it,” said Goldstein. “We were then able to clip the sensor to the harness.”

Understudied, overfished

Why anyone would go half-way around the world to study such an obscure animal like the Mediterranean slipper lobster is a fair question. Few scientists have bothered much with the species in the past, at least in terms of understanding their daily habits and routines. In fact, these lobsters are classified as “data-deficient” due to how little is know about them.

Elizabeth Dubofsky, a biological sciences instructor at the New England Institute of Technology who collaborated with Goldstein on the project, says overexploitation of slippers makes them a ripe target for a behavioral study. While slipper lobsters are not nearly as commercially-important as spiny and clawed lobsters (two other major groups), they have become a delicacy in Israel and throughout the Mediterranean in recent years, commanding a high market price.

“Part of the reason I wanted to work on this is because we know so little about slipper lobsters yet they have become so targeted in Israeli fisheries,” said Dubofsky. “It’s important to know if there are activity patterns that make them more or less vulnerable to commercial exploitation. Can we limit fishing or collecting of them during their breeding seasons, or is there something about a diurnal rhythms that makes them harder to catch?”

Dubofsky also cites the potential impacts of ocean acidification – the lowering of pH levels in the ocean caused by increased carbon dioxide (CO2) absorption – as a reason for paying closer attention to slippers.

“All animals with exoskeletons have to absorb calcium carbonate from seawater to develop shells,” she said. “As you increase CO2 in water, the water becomes more acidic and results in less available calcium carbonate, making it harder for slippers to create their shells.”

According to Goldstein, climate change in general may be a threat to slipper lobsters, and studying their behavior will help answer future questions such as how they respond to a warming Mediterranean Sea and how their seasonal migrations might change as a result.

“These lobsters have seasonal migrations just like clawed lobsters and will leave shallow waters for deeper waters,” he said. “The Mediterranean has been heating up substantially over the past decade and the average and maximum temperatures have changed. The temperature threshold for these lobsters to migrate could change so by figuring out what’s ‘normal,’ we can compare the changing environment to that normality.”

Off to the market

Diving. Photo credit: Rebecca Kibler.

Diving. Photo credit: Rebecca Kibler.

Just as the kinks had been worked out and the experiment gained momentum, two of the slippers croaked. They needed to be replaced, but as much fun as diving back down with a crowbar sounded, Goldstein chose a quicker – albeit more expensive – path.

He drove to a fish market in the city of Acre in northern Israel where, despite the handsome price, he bought a few slippers to replenish the study sample.

“No English was spoken,” said Goldstein. “So there I am, trying to communicate with the guy and tell him that I needed a few lobsters that are healthy and kicking with all their parts intact.”

Goldstein looked like a lively lobster himself, gesturing and waving his arms around to communicate as the fish dealer deadpanned back at him in incomprehension.

“He has no idea I’m trying to study them and just thinks I want to eat them for dinner.”

Understanding normal

Goldstein spent the next several months observing the lobsters in the lab and assessing their movements through a combination of activity data and time-lapse video. He eventually finished out the study, released the lobsters back into the water, and worked with Dubofsky to begin analyzing the data he worked so hard to collect.

The results – despite the grueling, year-long ordeal – weren’t all that earth-shattering. Not that they needed to be. According to Goldstein, any science on the biological and physiological traits of the Mediterranean slipper lobster was new science.

“The study confirmed some basic but important facts about the rhythmicity of these animals,” he said. “Like many other crustaceans, slippers march to the beat of a normal circadian (24-hour) rhythm, and they typically forage at night. We also found that they are able to anticipate environmental changes so they can return to their dens before having to do battle with predators.”

According to Dubofsky, it’s hard to picture a slipper lobster having to fight off another creature.

“It’s amazing, because when you see how formidable looking these lobsters are, you just can’t imagine anything ever going after them or eating them,” said Dubofsky. “They are so rock-solid.”

The final stretch

Having established these activity baselines – which are detailed online in the ICES Journal of Marine Science – Goldstein’s work in Israel was done. He packed up and flew back home to New England.

But, of course, it wasn’t Miller Time yet. While unpacking his things, he noticed a receipt on one of the bags indicating it had been inspected ‘behind the scenes’ at airport customs. He suddenly realized that the equipment case holding the activity sensors was gone. It turns out, the sensors, which likely appeared suspicious looking, had been confiscated at airport customs at some point during the trip home.

“I’m not sure if it happened when I left Israel or entered the States, but my stuff was gone,” said Goldstein.

While losing the gear stung a bit, the activity data had been preserved, making it possible for further analysis to be done. Goldstein, being the keen problem-solving scientist he is, had the good sense to back up all his data before hopping on the plane.

“Before leaving, I sent an email to myself attaching the data files, and saved a copy to Dropbox as well,” he said.

Good thing, too. Otherwise, Goldstein might have found himself in a wetsuit again with crowbar in hand, plunging in for another round of slipper hide-and-seek. Sometimes, all it takes is one thing to go right to save a whole experiment.

This study was funded in part by the U.S.—Israel Fulbright Fellowship program and a Sir Morris Hatter Research grant.

Copyright © 2015 by Marine Science Today, a publication of Marine Science Today LLC.

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  1. Steve "Ollie" Kilpatrick says:

    Great article!! Jason has been a friend of mine since 6th grade, and it’s great to see how far his hard work has taken him 🙂