Eric Brown of Edgartown has a secret.
Like many fishermen, when it comes to his favorite angling spot, Eric does not fish and tell. But, he did call last week to share a fish tale.
The star of the story is an unusual animal: an American brook lamprey, which, to be accurate, is not a true fish. True fish, taxonomically-speaking, have jaws, while lampreys are jawless. Lampreys also do not have bones, scales or paired fins.
These are not their only idiosyncrasies; during part of their lifecycle, they are also blind and toothless! “Sans teeth, sans eyes, sans taste, sans everything,” as Shakespeare said, even if he wasn’t speaking of these bottom dwellers.
You may wonder what there is left of them to talk about.
Well, to begin with, this freshwater species leads a unique and somewhat sordid life, as Eric found out when he observed a mass mating of lampreys on his fishing trip. Lampreys actually have a duallife. For three to five years, they exist in their larval form, and are calledammocoetes. As ammocoetes, lamprey cannot see, and they can eat only by filter-feeding algae from their home on the riverbottom.
When the time comes, lampreys (perhaps channeling their inner insect) metamorphose into a distinctly different adult form. Their eyes become functional, their mouth grows into a suction disc with horny teeth, and they become ready for their final love fest, an affair to beremembered!
Male lampreys make horseshoe-shaped gravel nests in the bottom of their stream, using their mouths to move stones into the desired shape. The family name of this species, Petromyzontidae, means stonesuckers.
Once the nest is set, the female attaches her mouth to an upstream rock and allows the male to attach himself to her head. They shake violently together, and they can include other lamprey in their matingritual. Eric saw more than a dozen together last week, and it is not uncommon to see groups of up to 40 lampreys spawning communally in one nest.
This last get-together is the end of the road for American brook lampreys, since they die soon after mating. Their egg and sperm mix in the nest, and larvae will hatch within two weeks to begin the cycle anew.
Brook lampreys are a rare species in Massachusetts, listed as threatened by the Massachusetts Division of Fisheries and Wildlife’s Natural Heritage and Endangered Species Program. According to its Web site, there are only 12 known populations in Massachusetts. Eric was very lucky to see this animal and its mating ritual, which occurs annually in mid-April and earlyMay.
To identify an American brook lamprey, look for an eel-like fish — which, as noted above, is not a fish, nor is it an eel either. It can reach lengths of up to eight inches, has one nostril between its eyes, and seven pairs of gill openings along its side. Its circular, suction cup mouth is also very distinctive, and this lamprey has a two-part dorsal fin along the top of itsbody.
The sea lamprey is the only other species of lamprey found in Massachusetts. It is easy to differentiate the two species, as the sea lamprey is much larger, reaching lengths of up to 18 inches, and it has a more pigmentedbody.
I might suggest running out to see the American brook lamprey doing its spring thing — if we only knew where they were. But Eric isn’t telling.
Suzan Bellincampi is director of the Felix Neck Wildlife Sanctuary in Edgartown.