Author: Reighard & Cummins, 1916
FBname: Northern brook lamprey
Comments: Freshwater. Generally associated with warmwater habitats and tolerant of variation in terms of discharge, water temperature, and substrate. Mainly inhabits warmwater, isolated segments of moderate-sized to large streams with summer flows 0.03-31 m3/s, summer water temperatures 14-25.6 ˚C  (Ref.89241).  Adults inhabit clean, clear gravel riffles and runs of small rivers. Ammocoetes occur in quiet water over sand, silt and debris (Ref.1998). Metamorphosis occurs in late August to September, in Michigan and extends to early October in Québec (Ref. 89241). Non-parasitic, the adults and possibly the larger ammocoetes in the resting stage do not feed (Ref. 1998). Adults live less than 6 months. In Michigan, the spawning period is from 13 May to 6 July, at water temperatures between 12.8-23.3 ˚C, with peak spawning activity in late May to mid-June. In Québec, spawning occurs in May, at water temperatures between 12.8-17.2 °C, peaking at temperatures between 13.3-15.6 °C. Nests are usually in the open and are poorly defined, but have also been found downstream of large stones 18-36 cm in diameter, or on a patch of gravel downstream of a submerged log. The nests are found in streams having 3.5-8 m width, 10-61 cm depth, and 0.1-0.6 m3/s flow. Up to 13 spawning lampreys have been found in a nest. There are reported occurrences in Michigan of communal spawning of Northern Brook Lamprey with Silver Lamprey (Pine River), and of Northern Brook Lamprey with Sea Lamprey (Devils River). Fecundity, 1,200 eggs/female. During spawning, adults preyed upon by <i>Ambloplites rupestris</i>.  In the Laurentian Great Lakes Basin, it has been negatively affected by control measures directed towards <i>Petromyzon marinus</i>, except for the chemosterilization of males, which affects only the latter species. Vladykov (1949) reported that in the province of Québec, Canada, fishermen use ammocoetes as bait for sportfishes (Ref. 89241).