Earth Matters: For the love of lampreys

  • Larval lampreys drift downstream and live in the soft bottoms of waterways. Great Lakes Fisheries Commission

  • ​​​​​​​Lamprey in spawning condition are a blotchy brown color. Great Lakes Fisheries Commission

  • The silvery fish at the center is a sea lamprey “transformer,” the juvenile stage of the species. Ken Sprankle

  • Lamprey in their nests await females to breed with. Boyd Kynard

For the Gazette
Published: 8/29/2020 11:56:02 AM

Consider the sea lamprey. Who couldn’t love such a face? With their ancient heritage, their complex lives and their glorious culinary history, these jawless, boneless fish are among the most fascinating of creatures. They live among us, out of sight, wanting only to feed and migrate to the ocean.

Sea lampreys evolved about 360 million years ago, more than 200 million years before the evolution of salmon and herring. They have only cartilage and a round mouth for sucking and rasping. In the last year or two of their lives they parasitize large marine fish, sucking the fish’s fluids, then dropping off and leaving scars, but rarely killing their hosts. The dark, silvery adults grow to between 2 and 4 feet and weigh up to five pounds.

Parasitism by juveniles and adults in the Atlantic Ocean accounts only for about a quarter of their life history. During late winter, adult sea lampreys cease feeding while at sea to make room for developing male and female gonads. 

As they mature, adults enter the mouth of the Connecticut River, where they wait as their bodies adjust to the change from salt to fresh water. After the spring freshets recede in May, they run upriver, mostly at night, along with shad, blueback herring and other anadromous species. 

In 2020, almost 34,000 sea lampreys were lifted over the Holyoke Dam on their annual run into scores of tributary streams, as far as the tributaries of Vermont’s White River, 220 miles from Long Island Sound. By the time they reach a hospitable stream, their bodies are in decline; they have turned a blotchy brown color and are mostly blind as they prepare to spawn.

Spawning adults construct a nest consisting of a shallow depression created by removing gravel and cobble in or at the head of rocky riffle habitat, and piling the rock just downstream of the nest depression. A single male claims a small breeding territory for its nest, where it courts one or two females, alternating building the nest with spawning over two or three days. 

Wrapping their bodies around each other, the male and female simultaneously extrude their gametes, and the eggs are fertilized in the water column, drifting past the rocks piled at the downstream end of the nest. The nest functions to slow stream velocity and increase fertilization of eggs. 

Eggs hatch in four to five days, and the eyeless larvae, called ammocoetes, drift downstream, living in the soft stream bottom, and feeding on microorganisms and particulate organic material. The larvae also release a pheromone, a scent that will lead the returning adults to spawning streams. After four or five years, ammocoetes develop into “transformers,” the juvenile life stage when they migrate down the Connecticut River during fall and spring to the estuary, where they become parasitic adults.

Despite a good run of lampreys this year, we’re seeing a long-term decline in their number, although we still have enough in our rivers to catch and eat them. 

The lamprey has a venerable culinary history in Europe, where they are also found. Lamprey pie was a great delicacy in the royal courts of England since the time of the kingdom’s founding in the 11th century. In the French kitchen, lamprey à la bordelaise is a luxurious traditional dish served at the grandest tables. 

However, a mystery remains: Why have we almost no indication of lamprey as part of the foodways of local Indigenous people? I could not even discover a traditional Abenaki, Nipmuc or Pequot name for the fish. Nor is there mention of lamprey fests in Colonial history. Herein lies a challenge for an enterprising anthropology student.

Lack of tradition, fortunately, did not prevent Andy Fisk, executive director of the Connecticut River Conservancy (CRC), from holding a small lamprey fest where Indigenous chef Neftali Durán (a CRC trustee) prepared a fine Spanish version of lamprey stew. The lamprey was firm and chewy, dense like tuna, but tasted like lamprey.

Lamprey stew aside, we have a lot to thank lampreys for. By migrating and then dying in the tributaries of the Connecticut River, sea lampreys deposit nutrients and materials from the ocean, enriching our woodland streams and soils, increasing the health of our ecosystems. Also, their cleaning and nest-building activities serve to “engineer” the substrate of tributaries. The lamprey leave behind nests in which minnows spawn, along with many millions of eggs, which provide food for minnows, trout and eels. 

Connecticut DEEP fisheries biologist Steve Gephard has seen aquatic insects covering lamprey carcasses and, in the fall, striped bass have been found with stomachs full of sea lamprey transformers. Walleye in the upper Connecticut River have also been found full of lamprey larvae and transformers. The watershed’s ecosystem has evolved with our anadromous fish, and our forests would be much poorer for their loss.

John Sinton is co-moderator of the Mill River Greenway Initiative, honorary trustee of the Connecticut River Conservancy, author of Devil’s Den to Lickingwater: The Mill River Through Landscape and History, and co-author of The Connecticut River Boating Guide. The author is indebted to the following experts and advocates for their help on this column and their heroic work in restoring our migratory fisheries: Steve Gephard of CT DEEP fisheries, Boyd Kynard of BK Riverfish, Ken Sprankle and Melissa Grader of the U.S. Fish and Wildlife Service, and Andy Fisk of the Connecticut River Conservancy. Further information can be found at www.tinyurl.com/earthmatters-53.

Earth Matters has been a project of the Hitchcock Center for the Environment for 11 years. In response to the Covid-19 crisis, the Hitchcock Center has developed special new programming, but their doors remain closed to the public and their budget is severely impacted. To help the Hitchcock Center through this very challenging time, please make a donation at www.hitchcockcenter.org.




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