Species Accounts
Umbridae - Mudminnows - Umbres
Mudminnows are freshwater fishes of the Northern Hemisphere found in Alaska, central and eastern North America, and in Europe and Siberia. There are only 7 species with 1 reported from Canada and the NCR.
They are characterised by the dorsal and anal fins being far back on the body near the tail as in the Pike Family, no adipose fin, a toothless maxilla bone in the upper jaw, no pyloric caeca (finger-like gut branches), branchiostegal rays 5-8, rounded tail fin, absence of a duck-billed snout and no groove between the upper lip and the snout.
The closest relatives of this small, innocuous fish are members of the large, predatory Pike Family.
Mudminnows, as their name indicates, are found in muddy or swampy areas. They can survive low oxygen conditions by breathing air. They can survive drying by burying themselves in the soft ooze and detritus. It is doubtful that they can survive complete desiccation of the habitat. There is evidence that some species can survive being frozen in ice and certainly the Canadian species remain active in winter under an ice cover, using oxygen directly from gas bubbles under the ice.
Central Mudminnow / Umbre de vase
Umbra limi (Kirtland, 1840)
Taxonomy
Other common names include Western Minnow, Mudfish, Mudpuppy, Dogfish and Mississippi Mudminnow.
Key Characters
This is the only species in the family in Canada and is easily recognised by the anal and dorsal fins being close to the tail, absence of a duck-like snout and by the vertical bar at the tail fin base.
Description
Dorsal fin rays 13-17, anal rays 7-10, pectoral rays 11-16 and pelvic rays 6-7. There is no lateral line and lateral scales number 30-39.
Colour
The head and body are brown, black or olive-green above, the flanks brown with traces of numerous bars in some fish and the belly white to yellowish. Fins are brown, sometimes tinged with pink or orange. Spawning males have iridescent green or blue-green anal and pelvic fins. The peritoneum is light brown with darker speckles.
Size
Size attained is 13.2 cm standard length (and 14.8 cm total length).
Distribution
Found in central North America west of the Appalachian Mountains south to Tennessee and Arkansas. In Canada it is found in southern Manitoba and adjacent areas of western Ontario and south of a line from the southeastern corner of Lake Superior across to about Québec City.
Origin
This species is entered the NCR from a Mississippian refugium.
Habitat
This species inhabits weedy and detritus-rich streams, ditches, bogs and small ponds where oxygen content may be low compares to other fish habitats. They may also be found in lakes. The bottom is usually mud and detritus but can be gravel and stones. Small (1883) reports them hovering in mid-water using the pectoral fins and darting violently to the surface and back at long intervals, presumably to gulp air.
Age and Growth
Females live longer than males and may attain 9 years of age, but this is uncertain as Mudminnow scales are difficult to "read" for age. Maximum age may be only 4 years. Males are mature at 1-2 years of age and females at 1-3 years.
Food
Mudminnows feed on bottom-dwelling animals such as crustaceans, insect larvae, worms, molluscs, rarely small fish but certainly other Mudminnows, and other small inhabitants of weedy, detritus-rich ponds and small creeks. Curiously only female Mudminnows ate fish in a Manitoba study and older females consumed mostly fishes. During winter this diet may contribute to egg development so that spawning can occur soon after ice break-up, and so young have longer to grow before facing their first winter. Prey is attacked by a swift dart from concealment in vegetation. Mudminnows are common prey for many larger fishes such as catfishes and members of the Pike and Sunfish families. The Northern Water Snake (Nerodia sipedon) eats this fish in Ramsay Lake, Gatineau Park (McMurray, 1984). Even birds, muskrats and foxes have been recorded as eating them.
Reproduction
This species moves upstream, onto shores or into ponds and marshes to spawn. Thellen (1994) gives a spawning temperature of 13°C for the Outaouais. Spawning occurs in early spring over flooded areas and up to 2286 eggs are produced which stick to vegetation and are abandoned by the parents. A female from the NCR caught on 19 April contained eggs 1.4 mm in diameter.
Importance
They have been used as bait fish and are excellent aquarium fishes as they do not require an air pump.
© Brian W. Coad (www.briancoad.com)