Species · Catostomus columbianus
Bridgelip Sucker
A small sucker of the Columbia and Fraser systems whose lower lip never quite splits in two, and the one most easily confused with a fish that is at risk.
Family
Catostomidae
Origin
Native
Status
Yellow list (BC); not listed by COSEWIC or under SARA
How to tell it
The bridgelip is the small sucker of the Columbia and Fraser systems, and its name is its field mark. In most suckers the lower lip is split down the middle into two lobes. In the bridgelip, as the Natural History Museum of Los Angeles County puts it, that cleft is shallow, so the two halves of the lower lip are not fully separated. Turn the fish over and you see a bridge of lip across the middle.
It is native, secure and of no interest as a sport fish; FishBase lists it as edible but not eaten. It matters to a fly angler for two reasons. It lives in trout water and feeds on the bottom like the trout do, and it looks enough like the mountain sucker, whose Pacific populations COSEWIC assessed as Special Concern, that any small sucker deserves a careful look before it goes back.
The quick read
FishBase gives the bridgelip a maximum length of about 30 cm and a common length nearer 16 cm, so it is the smallest of the four suckers on these pages. The BC Conservation Data Centre describes its habitat as lake margins and riffles, sand and silt runs, and backwaters of creeks and small to medium rivers with swift, cold water and gravel or rocky bottoms. FishBase says it probably eats algae and bottom invertebrates, and that its young may be eaten by some salmonids.
Telling it from the other suckers
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Largescale sucker: the bridgelip’s common neighbour in the Columbia system. Its lower lip is fully split, the cleft forming a broad inverted V, and it grows to twice the bridgelip’s size.
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Longnose sucker: long, pointed snout overhanging the mouth, a deep cleft in the lower lip, and fine scales.
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White sucker: short snout, narrow V-shaped cleft in the lower lip, and a deep tail wrist.
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Mountain sucker: the one that matters. COSEWIC’s 2010 report says the mountain sucker is the only other sucker with an incomplete cleft in the lower lip. It is told from the bridgelip by deep notches at the corners of the mouth, no small bumps on the front face of the lips, and lower scale and fin-ray counts. COSEWIC assessed its Pacific populations as Special Concern in 2010.
If you cannot tell a small joined-lip sucker apart, treat it as a possible mountain sucker and get it back in the water quickly.
Range in British Columbia
The BC Conservation Data Centre places it on the Pacific slope from the Fraser River south through the Columbia drainage, and ranks it S5 and Yellow listed. COSEWIC’s mountain sucker report records the bridgelip in the North Thompson, Similkameen and Columbia rivers, notes it is found more often in lakes than in streams in BC, and cites its presence in the Pend-d’Oreille River on the BC side. StreamNet’s Pacific Northwest list places it under the genus Pantosteus, a name some sources now use.
The app’s water lists name suckers only generically. In the Kootenays the Pend-d’Oreille is the water a source names; elsewhere, a joined-lip sucker is a fish to identify rather than assume.
If you catch one
A bridgelip that takes a nymph has found it on the bottom, where it feeds. Keep it in the water, cover its eyes if it struggles, and back the hook out with pliers, as the BC synopsis advises for any fish. One hooked outside the mouth has been snagged, and the synopsis says it must be released immediately. If you want trout rather than suckers, lift your nymphing rig a little off the stones.
Rules that apply
The 2025–2027 BC Freshwater Fishing Regulations Synopsis does not list the bridgelip or the mountain sucker as a protected species; the only sucker on its protected list is the Salish sucker, which the synopsis names under Region 2, the Lower Mainland. Province-wide rules apply: no live fish in your possession in the wild, no moving live fish between waters, no fin fish as bait except where the synopsis allows it, and no spear fishing in Region 4. Check the current synopsis before you fish.
Frequently asked questions
How do I check the lip without hurting the fish?
Cradle it upside down in the shallows for a few seconds and look at the lower lip. Split into two lobes: largescale, longnose or white. Joined across the middle: bridgelip or mountain sucker. Then let it go.
Do bridgelips and largescales hybridize?
None of the sources used for this page describe it. COSEWIC notes that the mountain sucker hybridizes with several other suckers, and that hybrids between the mountain and bridgelip suckers were not known to Smith in 1966, though there is some evidence they do occur.