Wednesday, April 29, 2015

Student Guest Post: Northern Brook Lamprey by Bobbielynn Richarchson

Title: Northern Brook Lamprey Ichthyomyzon fossor

Kingdom- Animalia
Phylum- Chordata
Class- Cephalaspidomorphi
Order- Petromyzontiformes
Family- Petromyzontidae
Genus- Ichthyomyzon
Species- I. fossor

There are 31 species of lamprey found in the world. Several of these species are threatened. However, the focus will be on the genus Ichthyomyzon, which has six species: I. bdellium, the Ohio lamprey, I. castaneus the chestnut lamprey, I fossor, northern brook lamprey, which is the focus of this discussion. I. gagei the southern brook lamprey, I. greeleyi the mountain brook lamprey also known as the Allegheny brook lamprey. And I. unicuspis or the silver lamprey (Minnesota Department of Natural Resources, 2015).
The northern brook lamprey, can grow to six inches in length with an eel like body shape without scales. They have small, almost nonexistent eyes and seven pairs of gills. And a continuous dorsal fin. In this species they have small, rounded teeth in a sucker like mouth. Many of these species are very similar in appearance, but have little traits that differentiate them from the northern brook lamprey. The adult chestnut lamprey and silver lamprey are distinguishable by their sharper and longer teeth (Government of Canada, 2010). Unlike some other lamprey species however, the northern brook lamprey is not parasitic during any of its life stages. The larvae are filter-feeders, consuming microscopic plant and animal life and decaying matter. Adults have a non-functional intestine and do not feed at all, living only on what was consumed in its larval stage. (Ministry of Natural Resources and Forestry, 2012).

The northern brook lamprey is found in small rivers and streams across the northeast part of the United States and parts of southeast Canada. Found in Pennsylvania only in a small portion of the northwest part of the state (Pennsylvanian Fish and Boat Commission, 2015). They prefer cool water streams, with a soft substrate like silt for the larval stage which are filter feeders. Adults have no digestive system at all and rely on the food stores collected during growth of their larval stage. Adults are typically found over coarse substrate, sand or gravel, in swifter waters, riffles, or runs. Larval stages are found burrowed in fine sediment or organic debris in side channels or other quiet water in areas with embedded woody debris (Minnesota Department of Natural Resources, 2015).
They are a major source of food with predators like rainbow trout, brown trout and rock bass. And because they are a non-parasitic species they pose no threat to freshwater fish or people. Economically, they have been used as bait in the past, but otherwise have no use to humans.
Spawning occurs in May and June and individuals becomes sexually mature at around six years. The males use the soft silt and small pebbles using their sucker like mouth to create small nests. These nests take the form of shallow depression in the substrate on the bottom of the stream. Up to 30 lamprey may spawn together in one area. They will lay up to 1000 sticky eggs are deposited in the nest and adhere to the substrate. (Ministry of Natural Resources and Forestry, 2012). After reproducing, like many fish species, the lamprey will die a few days later. Eggs take two to four weeks to hatch into the larval stage which are free swimming and begin feeding to build up the nutrients required as adults during mating. (Karvel-Fuller, B. 2013.)
The use of lampricides for the control of the invasive sea lamprey (petromyzon marinus) including lampricide TFM (3-trifluoromethyl-4-nitrophenol) kills larvae before they develop lethal mouths and migrate to the lakes to feed on fish. Unfortunately this treatment also kills nonparasitic species like the northern brook lamprey. And bayluscide a liquid or powdered form of this can be used alone or combined with TFM to reduce the amount needed during treatments. Both can also have negative effects on amphibians and some freshwater fish (Government of Canada, 2010).
Pollution and changes in water levels and temperature have made it difficult for eggs to develop and hatch properly, dropping the already low survival rate of larval stage lamprey. Habitat degradation along stream beds is also a problem as it removes the substrate that the lamprey need for reproduction. Most is caused by humans thanks to aggricultureal runoff and erosion of stream banks that cause water levels to drop and temperatures to rise with larger surface areas (Karvel-Fuller, B. 2013).

Habitat protection is the only management system used, although only generally, as they aren’t considered economically important. Because of this the species despite being endangered has been ignored by different species protection agencies. There are relatively simple things that can be done to help maintain populations.
By building up and maintaining plant buffers it is possible to avoid contamination from agricultural areas. One of the best ways to do this, and it is a cheap solution that can be implemented by both farmers and agency official, employing best management practices for around freshwater streams. This includes planting native plants to stop erosion and help filter runoff, and also the creation of stream zones that are left undisturbed to give optimum condition for the lamprey.
Watershed management is also necessary to protect the undisturbed habitat and water quality required by the northern brook lamprey. Frequent testing of water for safety is recommended, if issues arise the buffer system can be implemented. Control of lamprisides, and pollutants that effect sensitive freshwater organisms is also going to be a major challenge in protecting this species. By implementing non-chemical means of control like lamprey walls, which collect sea lampreys but have spaces for smaller species to swim through, or hand collection, it will increase survival of the species (Karvel-Fuller, B. 2013).

Government of Canada, 2010.  Aquatic Species at Risk - The Northern Brook Lamprey (Great Lakes –
Upper St. Lawrence). Fisheries and Oceans Canada. Accessed March 10, 2015.
Pennsylvanian Fish and Boat Commission, 2015.  Gallery of Pennsylvania Fishes. Lampreys. Accessed
Ministry of Natural Resources and Forestry. 2012. Species at Risk. Northern Brook Lamprey. Accessed
Minnesota Department of Natural Resources, 2015. Ichthyomyzon fossor (Northern Brook Lamprey).
Karvel-Fuller, B. 2013. "Ichthyomyzon fossor" (On-line), Animal Diversity Web. Accessed March 10, 2015

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