Mottled Sculpin
  • Side view adult.
  • Side view adult.
  • Side view adult.
  • Top view adult.
  • Bottom view adult.
  • Head-on view adult.
  • Close-up flank.
  • Close-up head.
  • Close-up mouth and snout.
  • Close-up tail.
  • Close-up dorsal fin.
  • Close-up anal fin.
  • Close-up pectoral fin.
  • Close-up pelvic fin.
  • Notice that the two dorsal fins are connected, the lateral line ends under the 2nd dorsal fin, there are no scales; CPL/POD < 1.
  • View of underside of head: Notice that the gill membranes are broadly joined forming a shallow angle; there are two midline chin pores (invisible).
  • Close-up pelvic fins: The pelvic fins are not fused and have 4 rays; the spine is fused with the first ray to form one element.
  • View of inside of mouth: Notice the presence of palatine teeth.
  • Close-up pelvic fins: Notice that the pelvic fins are not fused; there are 4 rays; the spine is fused with the first ray to form one element.
  • Close-up head: The profile is dorso-ventrally flattened and there is a preopercular spine.
  • Alternate side view of a round goby (top) and mottled sculpin (bottom): Notice the differences in the scales and the pelvic fins.
  • Alternate side view of a round goby (top) and mottled sculpin (bottom): Notice the differences in the scales and the pelvic fins.
  • Alternate side view of a round goby (top) and mottled sculpin (bottom): Notice the differences in the scales and the pelvic fins.
  • Alternative top view of an adult.
  • Alternate bottom view of a round goby (top) and mottled sculpin (bottom): Notice the differences in th pelvic fins (fused/separate).
DescriptionSimilar Species
Family
Sculpins (Cottidae)
Body
Mouth and snout: Terminal and very wide, with bands of fine teeth in bands on upper and lower jaws. No barbels. Snout rounded to blunt and dorsal-ventrally flattened. Body patterning, color, and scales: Mottled with irregular blotches, dark brown or black on a brown background with a cream or whitish belly. No scales, but a few fine prickles anteriorly just below the lateral line. Fins with brownish speckles, spots, and/or blotches. Body shape and size: Body dorsal-ventrally flattened, especially anteriorly. Typically 35-100 mm (1.5-4 in) TL; maximum about 137 mm (5.5 in).
Fins
Tail, dorsal and other fins: Rounded or square tail. Two dorsal fins, slightly connected, the anterior with 6-9 flexible spines and the posterior with 17-19 rays (counting last forked ray as one). Pelvic fins thoracic, each with 1 spine and 4 rays. No adipose fin. Anal fin with 13-15 rays (counting last forked ray as one) and no spines.
Distinguishing Characteristics
The mottled sculpin can be distinguished by its pair of free and independent pelvic fins and its lack of scales. See also similar species information.
Breeding Adults
Male may become very dark, with an orange edge to the first dorsal fin.
Juveniles
Similar to adults.
Hybrids
Mottled sculpin X slimy sculpin reported from Wisconsin but unconfirmed; known from elsewhere (no photos).
Compare Similar Species
Pelvic Rays
Sculpin, Deepwater3
Sculpin, Mottled4
Sculpin, Slimy3
Sculpin, Spoonhead4
Prickles
Sculpin, DeepwaterFew, just above lateral line
Sculpin, MottledFew, below lateral line
Sculpin, SlimyFew, below lateral line
Sculpin, SpoonheadMany, on head and back
Lateral Line
Sculpin, DeepwaterComplete, or nearly so
Sculpin, MottledEnds below 2nd dorsal fin
Sculpin, SlimyEnds below 2nd dorsal fin
Sculpin, SpoonheadComplete
Dorsal Fins
Sculpin, Deepwater1st and 2nd clearly separate
Sculpin, Mottled1st and 2nd touching
Sculpin, Slimy1st and 2nd touching
Sculpin, Spoonhead1st and 2nd touching
Gill Membranes
Sculpin, DeepwaterNarrowly joined, meet at acute angle
Sculpin, MottledBroadly joined, meet at shallow angle
Sculpin, SlimyBroadly joined, meet at shallow angle
Sculpin, SpoonheadBroadly joined, meet at shallow angle
Exposed (not covered with skin) Preoperculer Spines
Sculpin, Deepwater2-4; largest greater than or equal to 1/2 of eye diameter in length
Sculpin, Mottled1; ~1/2 of eye diameter in length
Sculpin, Slimy1; ~1/2 of eye diameter in length
Sculpin, Spoonhead1; greater than 2/3 of eye diameter in length
Midline Chin Pores
Sculpin, Deepwater1-2?
Sculpin, Mottled2
Sculpin, Slimy2
Sculpin, Spoonhead1
Palatine Teeth
Sculpin, DeepwaterPresent
Sculpin, MottledUsually present
Sculpin, SlimyUsually absent
Sculpin, SpoonheadAbsent
Ratio of Caudal Peduncle Length to Post-Orbital Distance
Sculpin, Deepwaterless than or equal to 1
Sculpin, Mottledless than or equal to 1
Sculpin, Slimygreater than or equal to 1
Sculpin, Spoonheadless than or equal to 1
Similarity Index
Sculpin, DeepwaterVery similar
Sculpin, MottledN/A
Sculpin, SlimyVery similar
Sculpin, SpoonheadVery similar
Comments
Sculpin, MottledModerately similar to round goby and tubenose goby, but distinguishable by its pair of free and independent pelvic fins and its lack of scales. In the gobies, the two pelvic fins are fused to form a disk and scales are present.
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