Lampreys: Still Hangin’ Around

The Lampreys: Still Hangin’ Around

Mountain Brook Lamprey by Rob Criswell photos by the author

If there is one piece of advice that is most appropriate for Ohio lamprey is rather widespread and common in the the non-parasitic lampreys, it’s “Get a life!” Look at you! Allegheny River system, where it lives in medium-sized You’re born. You drift aimlessly about. You slither into a creeks up to the Allegheny River itself. These two parasites mass of sand, muck and sticks. You live in a burrow for are smaller (up to 11 inches for the Ohio and 13 inches for years, as a larva of all things. You survive on microscopic- the silver, as adults) than the sea lamprey and generally have sized orts that drift past. When you finally turn into an little impact on other fishes that they coexist with. adult, you don’t eat a single meal. And, you breed and die Our cast of diminutive (4 to 8 inches as adults) shortly thereafter. non-parasitic lamprey characters includes possibly the Pennsylvania is host (no pun intended) to seven lamprey Commonwealth’s most rare, regularly occurring fish species, three are parasitic and four are not. And, although species. The American brook, least brook, mountain brook their life cycles are unconventional to say the least, these and northern brook lampreys, all inhabit, as their names eel-like leftovers from ancient times are important elements suggest, smaller waterways including spring runs, brooks, of our native fish fauna. creeks and occasionally small rivers. Our parasitic species include the Ohio, silver and sea After spawning, helpless lamprey hatchlings drift lamprey. As adults, they attach themselves to a fish by downstream until they encounter suitable habitat in slower a toothy, suction-disk sort of mouth and rasp and suck water in which to develop. These nurseries consist of nutrients from this luckless “host.” The sea lamprey is sand, silt, muck and detritus (dead and decaying coarse infamous for its invasion of the Great Lakes and the crash vegetation) with a consistency that allows the excavation of lake trout and other fisheries it caused in those waters. Its of a small burrow. There, they filter-feed on algae and large adult size (up to 24 inches in landlocked populations protozoans that drift past through a hood-like funnel and nearly 48 inches in sea-run specimens) and feeding around their mouth. They spend 3 to 6 years in this austere habits make it a formidable predator. But, many don’t realize existence as they develop into adulthood. These developing that the sea lamprey is native to and still common in the larval lampreys are call “ammocoetes,” and they may grow Delaware River and its tributaries, where it is in balance with larger in this form than they will be when they are adults. other organisms there. The transformation from ammocoete to adult begins The silver lamprey inhabits large rivers and lakes. It in the late summer or early fall. By spring, the “hood” has only been documented in Pennsylvania a few times, is replaced by a toothy oral disk (also called a “buccal in tributaries to Lake Erie, and probably does not spawn funnel”), which permits the efficient attachment to the regularly here. Recent survey work has revealed that the host fish. The teeth in this disk are well developed in

54 Pennsylvania Angler & Boater • July/August 2013 PFBC Facebook: PaFishandBoat The mountain brook lamprey inhabits smaller waterways. The silver lamprey inhabits large rivers and lakes. As adults, they This non-parasitic lamprey occurs in fairly small numbers attach themselves to fish by a toothy, suction disk mouth and in the Allegheny River drainage and a few places in western rasp and suck nutrients from its host. Pennsylvania. parasitic species but not so much in those that will not Always rare to begin with, this lamprey has been impacted feed. Pennsylvania lampreys spawn in communal nests in by habitat loss and almost certainly by a federal Great Lakes April and May. Undulating masses of spawning lampreys sea lamprey control program. It is listed as an endangered in shallow riffles have been referred to as “dead men’s species in Pennsylvania. fingers” in northwestern Pennsylvania. They die shortly The best news that resulted from the recent survey after spawning, and it is not unusual for researchers to find work is that the American brook lamprey is doing well in pools with dead and dying lampreys lying about during Pennsylvania. It was found in many smaller streams that these months. were not been previously surveyed. Formerly a candidate Survey work that has resulted from funding through species, as a result of these recent efforts it was delisted in programs such as State Wildlife Grants, the Wild Resource December 2012. In addition, the Ohio lamprey, mentioned Conservation Program and County Natural Heritage earlier, now appears to be more common than records Inventories has greatly increased our knowledge of the previously indicated, as is under consideration for delisting. status of our brook lampreys in recent years. Generally, With the exception of the sea lamprey (in a negative these species have restricted distributions in the state, sense) lampreys are of little economic value to man. They but their status varies. Populations of the least brook serve as prey for gamefish and are considered a delicacy lamprey, a candidate species, have changed little over the in parts of Europe, Japan and South Korea. And, they are past 25 years, and it appears to be uncommon but stable. sometimes used in biomedical research. Its primary range is scattered through the Ohio River Although many Pennsylvanians rarely see them, lampreys drainage in the southwest region of Pennsylvania, but are important environmental indicators—canaries in the there is also a small occurrence in the Susquehanna River coal mine of sorts. They are rather intolerant of degraded drainage in southernmost Chester County. conditions and pollution, and the fact that some are The mountain brook lamprey occurs in fairly small listed as endangered, threatened or candidate species and numbers in the Allegheny River drainage and a few places absent from many waterways tells us our water quality in western Pennsylvania. It too appears to be somewhat improvement work is far from complete. stable but exists in small numbers. It is classified as a The lampreys also make up an important chapter in our threatened species. environmental history. Although barely fishes, lacking jaws The dubious distinction of being our most rare fish and paired fins and held together by a skeleton of cartilage, probably should be bestowed upon the mountain brook they are considered the most primitive of the finny tribes lamprey. First discovered in a tributary to Lake Erie in and the oldest living. 1968, it has been collected only a few times since that Due to their absence of real bones, fossil lampreys dating instance. In fact, a specimen found in 2009 was the first back 360 million years have reported. adult documented in the state in more than 30 years. Although it isn’t much of a life, it works for the lampreys.

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