A while back I got a call from a boat owner visiting Belfast who wanted his hull cleaned. I met him down at the town dock and worked on the 34-foot sailboat. Everything went fine. However, when I swam over to the boat ramp to exit the water, I found I was heavily covered with lots of skeleton shrimp. They were all over me and my gear. And I mean A LOT! There must have been hundreds if not more of them, crawling all over me.

Skeleton shrimp dot my dive glove after I descend an anchor line. Photo by Charles H. Lagerbom.

Skeleton shrimp get little respect; they are kind of like the Rodney Dangerfield of Maine shrimps. That is probably because they are not even real shrimp, but rather crustaceans more akin to lobsters. They are not very big either; most of the ones on me were a half-inch or less.

Their relatives include sand fleas and whale lice. Yikes! A dive buddy of mine who works at a fish farm says they cover everything there, the lines and nets and floats. He says he has been infested with them numerous times and that they really like facial hair.

Skeleton shrimp are Caprella spp. from the amphipod family Caprellidae. They got the name skeleton shrimp because they are transparent; you can see their innards through the skin. Which is why these tiny creatures are sometimes also called ghost shrimp.

Close-up of a Skeleton shrimp. SINC: Servicio de Informacion y Noticias Cientificas and J.M. Guerra-Garcia

Skeleton shrimp have two pairs of legs on the front of their bodies and three pairs on the back. The body is long and cylindrical, segmented like lobsters with a head, thorax, and abdomen. However, the skeleton shrimp body is broken into seven long segments.

They are considered to be the praying mantises of the sea — ready to clamp onto passing food items, including detritus, worms, smaller amphipods, and larvae. They are omnivorous. The front forward legs form powerful claws for defense and capturing food and give them the praying appearance. These grasping appendages are called pereopods.

Skeleton shrimp use their antennae to filter feed and move about the water. Their back legs have strong claws that clamp and cling to other surfaces. Locomotion is by using their front legs and then back legs, kind of like an inchworm.

Full body image of a half-millimeter long skeleton shrimp. SINC: Servicio de Informacion y Noticias Cientificas and J.M. Guerra-Garcia

And this is probably why they clung to me that day. I must have brushed up against the floats on the dock with my tank and back while scrubbing the side of the boat. with the skeleton shrimp clustered on the dock floats in large masses, my tank must have dislodged them in huge clumps, so they naturally then snagged onto me.

To grow, skeleton shrimp shed their exoskeleton to form a larger one. Males tend to be far larger than females, which can measure less than a 10th of an inch in length. For the female, this is the only time, during this in-between exoskeleton period, when they can mate.

Upon completion of mating, females then kill the male. This is done by injecting venom using the female’s sharp jaw. She then deposits the eggs into a brood pouch on the middle part of her body. Skeleton shrimp hatch directly into juvenile adults.

Their typical locations include sub-tidal substrates and shallow or deep water; they have been found at depths over a thousand feet! But most are near the surface near docks and floats and mooring balls.

There has been some commercial harvesting of the larger ones, usually collected here from December to April. Gathered by a dip net, they are usually sold in packages of a half dozen or more. The Gulf of Maine Inc. in Pembroke sells them by the pack.

Pictured is the larger Japanese invasive species of skeleton shrimp Caprella mutica. Creative Commons Attribution-Share Alike 4.0 © Hans Hillewaert

Maine indigenous species do not get very big, less than a 10th of an inch, but bigger sized skeleton shrimp have moved into the area. Known as Caprella mutica, they are an invasive species originally from the Sea of Japan. Showing up in increasingly larger numbers in Maine waters, they out-compete native species, even with real shrimp, nudibranchs, jellyfish, and sea anemones preying on them all.

Now I have encountered skeleton shrimp before; brushing against a mooring line or descending on an anchor chain, you usually get a few on your gloves or suit. But I was not prepared for the huge profusion of them all over me! I was like the guy covered with bees!

They were wicked crawling about, my face included, as I exited the water. Masses of them were on my buoyancy compensator throughout the webbing and in every nook and cranny of my gear. Kind of skeeved me out, that’s for sure!

I brushed off as many as I could right then; they were happy to get back into the water. Swiped off a whole bunch more at the car as I started to de-gear. But then also had to wash a bunch more off the suit and gear back at home, when I did the regular post-dive soaking, rinsing, and cleaning with freshwater.

More skeleton shrimp cling to my dive glove. Photo by Charles H. Lagerbom

After the suit and gear had hung to dry for a day or so, I still found myself scraping dried pieces of them off like dandruff! In fact, there was a pretty good pile of them below the drying rack, which I swept up and dumped in my back yard for fertilizer.

I will never look at an “all the shrimp you want deal” again in the same way. I have had my fill!

Charles Lagerbom teaches AP U.S. History at Belfast Area High School and lives in Northport. He is author of “Whaling in Maine” and “Maine to Cape Horn,” available through Historypress.com.

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