Silver Lamprey
  • Adult silver lamprey.
  • Side view adult.
  • Side view adult.
  • Top view adult.
  • Bottom view adult.
  • Head-on view adult.
  • Close-up flank of a large adult with pigmented lateral pores. Pores are unpigmented in smaller adults
  • Close-up head.
  • Close-up mouth and snout.
  • Close-up tail.
  • Close-up dorsal fin.
  • Close-up teeth: Notice the unicuspid circumoral teeth and the close-together supraoral teeth.
  • Close-up head region: Count of myomeres starts past last branchial pore; there are 46-53 trunk myomeres.
  • Close-up dorsal fin: There is a connection between the 1st and 2nd dorsal fin lobes.
  • Close-up teeth: Notice the unicuspid circumoral and the closely spaced supraoral teeth.
  • Close-up teeth: Notice the unicuspid circumoral and the closely spaced supraoral teeth.
  • Count myomeres from last branchial pore to anus. Notice the connected dorsal fin.
  • Whole body view of an ammocoete (larval stage). Juveniles have no eyes or sucking disk.
  • Close-up head of an ammocoete (larval stage). Juveniles lack eyes and have a hood-like mouth.
  • Close-up mouth of an ammocoete (larval stage). Juveniles have soft sieve-like tissues in the mouth.
  • Close-up tail of an ammocoete (larval stage). Juveniles have connected dorsal fin lobes.
  • Alternative side view of a small adult.
  • Alternative view of the mouth of a small adult.
DescriptionSimilar Species
Lampreys (Petromyzontidae)
Mouth and Snout: Sucking disk in adults, flexible hood in juveniles, no jaw. Teeth well-developed and sharp in adults; none in juveniles. No barbels. This parasitic species has unicuspid circumoral teeth (rarely 1 or 2 bicuspid out of 9 or 10 teeth. Gill openings consist of seven circular holes. Body Pattern: Large adults are blue or blue-gray on the sides and back and grayish or bluish on the lower surface. Solid color. Dark gray, silver gray, or brownish dorsal surface and flanks, grading to light gray/brown or off-white ventrally. Lateral pores mainly unpigmented, except in large adults. Body Shape: Elongate, cylindrical, flexible body. Typical adult size is 260-320 mm, with a maximum of 385 mm TL.
No paired fins; tail is spade-like and continuous with the dorsal and anal fins. Rounded tail. Dorsal fin is two lobed with no spines. No pectoral, pelvic, or adipose fins.
Distinguishing Characteristics
Eel-like body and sucking disk identify the lamprey family. First and second dorsal fins broadly connected. Lateral pores mainly unpigmented, except in large adults. Adults only: maximum disk diameter greater than maximum body diameter; supraorbital lamina teeth cusps close together, inner circumoral teeth unicuspid. Maximum length 385 mm TL. 46-53 trunk myomeres. See also similar species information.
Breeding Adults
Lampreys spend most of their lives as ammocoetes. They transform to the adult form in the fall, cease feeding, breed in the spring, and die. The adult form is the breeding form.
Ammocoete form. Distinguished from adults based on head and mouth characteristics. Ammocoetes lack eyes, have a hood-like covering of the mouth without a papillary fringe, and have soft sieve-like tissue in the mouth. Young adults are usually light yellow-tan, lighter on belly and gradually darkening toward the back; the sides are sometimes mottled, and occasionally slatey. Note that there are no reliable characters for consistently distinguishing Ichthyomyzon ammocoetes. The photo shown here for the juvenile form is a northern brook lamprey.
None known from Wisconsin.
Compare Similar Species
1st and 2nd Dorsal Fins
Lamprey, American BrookSeparated
Lamprey, ChestnutConnected
Lamprey, Northern BrookConnected
Lamprey, SeaSeparated
Lamprey, SilverConnected
Lamprey, Southern BrookConnected
Trunk Myomeres
Lamprey, American Brook64-75
Lamprey, Chestnut51-56
Lamprey, Northern Brook46-56
Lamprey, Sea63-73
Lamprey, Silver46-53
Lamprey, Southern Brook49-57
Lateral Pores
Lamprey, American BrookUnpigmented
Lamprey, ChestnutPigmented
Lamprey, Northern BrookUnpigmented
Lamprey, SeaUnpigmented
Lamprey, SilverUnpigmented (pigmented in large adults)
Lamprey, Southern BrookPigmented
Maximum Disk Diameter Relative to Maximum Body Diameter in Adults
Lamprey, American BrookLess
Lamprey, ChestnutGreater
Lamprey, Northern BrookLess
Lamprey, SeaGreater
Lamprey, SilverGreater
Lamprey, Southern BrookLess
Supraoral Lamina Teeth
Lamprey, American BrookWidely separated
Lamprey, ChestnutClose together
Lamprey, Northern BrookClose together
Lamprey, SeaClose together
Lamprey, SilverClose together
Lamprey, Southern BrookClose together
Inner Circumoral Teeth
Lamprey, American BrookBicupsid
Lamprey, ChestnutBicupsid
Lamprey, Northern BrookUnicupsid
Lamprey, SeaBicupsid
Lamprey, SilverUnicuspid (rarely 1 bicuspid)
Lamprey, Southern BrookBicupsid
Maximum Total Length (mm) in WI
Lamprey, American Brook202
Lamprey, Chestnut271
Lamprey, Northern Brook171
Lamprey, Sea760
Lamprey, Silver385
Lamprey, Southern Brook~170
Similarity Index
Lamprey, American BrookModerately similar
Lamprey, ChestnutVery similar
Lamprey, Northern BrookVery similar as ammocoetes, moderately similar as adults
Lamprey, SeaModerately similar
Lamprey, SilverN/A
Lamprey, Southern BrookVery similar as ammocoetes, moderately similar as adults