Species of the Month

These species have been featured in our FYI newsletter as "species of the month."

• Brook Lampreys
• Snapping Turtle (Chelydra serpentina)
• Spotted Salamander (Ambystoma maculatum)
• Eastern Hog-nosed Snake (Heterodon platirhinos)
• Blue Ash (Fraxinus quadrangulata)
• Brook Trout (Salvelinus fontinalis fontinalis)
• Wood Frog (Rana sylvatica)
• Smooth Serviceberry (Amelanchier laevis)

Brook Lampreys

Two species of brook lamprey are found in the Thames watershed. The American Brook Lamprey (Lampetra appendix) has been recorded in about half a dozen locations scattered throughout our area. Like our native Brook Trout, this species seems to require water temperatures that remain cool, rarely going above 22º C. As such it is a good indicator of coldwater conditions and streams where trout may persist or where trout re-introduction may be a possibility.

Until a few years ago, only very dated (1884, 1931, 1974) and suspect Thames records existed for the Northern Brook Lamprey (Ichthyomyzon fossor). In 2004, a population of this species, considered a “Special Concern” species at risk federally and provincially, was discovered in a South Thames River tributary near London. Further sampling has confirmed the presence of an apparently stable population.

Brook lampreys’ reputation suffers from their superficial similarity and distant relationship to the Sea Lamprey, a very destructive invasive species that attacks Great Lakes gamefish and was largely responsible for the widespread Lake Trout decline. Unlike their relatives, brook lamprey are non-parasitic. For most of their lives they are blind larvae, emerging occasionally from their tunnels in soft stream substrates to feed on algae and organic debris. After five to seven years they change into the adult form, spawn, and die.
Although little is known about brook lamprey biology, American Brook Lamprey are likely a significant component of coldwater aquatic ecosystems, while Northern Brook Lamprey play a similar role in warmwater systems.

Brook lampreys are similar in shape to eels, and have a series of uncovered round gill openings on the sides of the head, behind their eyes, and a single nostril on the upper surface of the head. Pictured is the American Brook Lamprey.

The Northern Brook Lamprey is a small, non-parasitic lamprey with small eyes and seven pairs of gill openings. It has a dark greyish brown back and sides, and a pale grey or silvery white belly. (Photo: Lucas Foerster)

Contact: , Aquatic Biologist

TOP