Semotilus margarita
Pearl Dace

Pearl Dace

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Name:

  • Semotilus, from the Greek, sema, "banner"; and the second part meant to mean "spotted"
  • margarita, from the Greek, "pearl"
  • Common name
  • Other common names include: Nachtrieb Dace, Northern Dace, Northern Pearl Dace, Northern Minnow

Taxonomy:

  • Kingdom Animalia
    • Phylum Chordata, animals with a spinal chord
    • Subphylum Vertebrata, animals with a backbone
      • Superclass Osteichthyes, bony fishes
      • Class Actinopterygii, ray-finned and spiny rayed fishes
      • Subclass Neopterygii
      • Infraclass Teleostei
        • Superorder Ostariophysi
        • Order Cypriniformes, minnows and suckers
        • Family Cyprinidae, carps and minnows
          • Genus Semotilus, the creek chubs
  • Minnesota Pearl Dace are of the subspecies Semotilus margarita nachtriebi, named after Professor Henry Nachtrieb, of the University of Minnesota and former director of the Minnesota Zoological Survey.
  • Also known as Margariscus margarita

Description:

  • A stout-bodied, cold water minnow.
  • Length up to 6", 3"-4" average
  • Coloration
    • dusky mottled on the upper sides (many of the scale pockets on the sides are darkened, giving the mottled appearance)
    • silver grey to white on the lower sides
    • white belly
    • usually a dark spot near the base of the tail
    • dark lateral band is distinct on the young, but fades in adults
    • adult males have orange-red sides below the lateral band
    • females may also show some color during spawning
  • Body
    • elongated form, nearly cylindrical in cross section
    • usually complete lateral line of 62-78 scales
    • dorsal, anal, and pelvic fins of 8 rays
    • pectoral fins of 15/16 rays
  • Head
    • mouth terminal, nearly horizontal with the upper jaw, separated from the snout by a groove
    • small barbel in the groove of the upper jaw (occasionally lacking)
    • hooked pharyngeal teeth in a 2, 5-4, 2 pattern, but count is variable.
  • During the breeding season, males have a pink to red-tinted stripe along their lower sides, and the upper sides of the pectoral fins bear paired rows of small, sharp tubercles.

Identification:

Distribution:

  • Native range centered in the northern Great Lakes states with extensions from Nebraska into New Foundland; scattered populations in central Canada
  • A relict or remnant population is found in parts of South Dakota, Nebraska and northern lowa.

Habitat:

  • Cool bogs, ponds, lakes, creeks, and clear streams.
  • Cool, boggy waters of lakes and ponds and in the cold headwater streams often associated with trout.

Associates:

  • Feeds on algae, aquatic insects, free-floating animal plankton, and a variety of other small aquatic organisms.
  • A forage fish for larger sport fishes in some waters.

History:

  • State Endangered in Iowa.
  • State Threatened in South Dakota

Uses:

Reproduction:

  • Spawns in late spring to early summer, in clear water with a weak to moderate current, over sand or gravel.
  • No nest is built, but the small spawning area is guarded by the male.

Comments:

Links:

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Last updated on 15 October 1999