Coastal Cutthroat Trout

Coastal cutthroat trout in non-spawning coloration.
NPS Photo: Lexa Meyer

(Oncorhynchus clarki clarki)

Other names: Harvest Trout, Sea-Run Cutthroat Trout, Cuts

Coastal cutthroat trout are silvery in coloration with a darker gray or olive back and numerous small black spots evenly distributed over the entire body (Fig. 25). These fish average 12-16 inches but can reach up to 20 inches in length. Spawning individuals of both sexes may develop darker coloring and a pink side stripe similar to rainbow trout (Fig . 26). The characteristic orange slash marks under the jaw may be faint or absent. These orange markings may or may not become more prominent as the fish near spawning readiness. Cutthroat (and coastal rainbows) both exhibit teeth on the head and shaft of the vomer, a bone located at the back of the mouth in the upper jaw (Fig. 27). But cutthroat trout also exhibit small teeth, often difficult to see, on the floor of the mouth behind the tongue. Coastal cutthroat trout exhibit a wide variety of life history strategies ranging from stream resident to sea-run (anadromous) forms. Sea-run forms typically stay quite close to home and rarely venture more than 50 miles from their natal streams.

 

Coastal cutthroat trout in spawning coloration.
Photo: Alaska Department of Fish and Game

Abundance, distribution, and natural history

Forty two cutthroat trout records currently exist, documenting their presence among 16 different stream systems within the park and preserve (however, only 55% of these records provide abundance information). Five of these drainages contain lakes. Coastal cutthroat trout probably occur throughout many park stream systems but their distribution and abundance is poorly known. Most populations are probably small, consisting of perhaps a few hundred fish. Drainage basins containing lakes are thought to be more likely to harbor this species.

Fish typically rear from two to five years in freshwater before going to sea. Cutthroat may reside for a few to perhaps 100 or more days at sea before returning to natal streams to spawn from late April to early June. Cutthroat do not seem to move between river systems as often as do anadromous Dolly Varden char and are probably not ready colonizers of recently deglaciated stream habitat. Similar to steelhead, cutthroat trout may repeat spawning every few years but survival for repeat spawning adults is similarly reduced.

Juvenile growth rates and residency along with adult residency and reproductive timing are poorly documented within Glacier Bay. Fry and juveniles have been reported in streams from June through November. Adults have been observed in streams from April through October.

 

Location of teeth on the vomer bone (roof of mouth) of a coastal cutthroat trout or coastal rainbow.
Illustration: Morrow 1974

Conservation measures and concerns

Cutthroat are generally quite vulnerable to angler overharvest because of their predatory nature and willingness to strike a lure. Southeast Alaska spawning populations are typically small. Multiple cutthroat populations often overwinter together in lakes and these aggregations rarely exceed 2,000 fish. Recreational harvest limits are generally conservative (2 fish daily; 11-22 inch size limit) compared with Pacific salmon species. More information is needed on the distribution and abundance of this species.

 

Relative (averaged across records) coastal cutthroat trout stream residency. Values in parenthesis indicate number of records for each month (total n = 23 records).