Washington State Status Report for the Margined Sculpin

The margined sculpin (Cottus marginatus) is physically distinguishable from the piute sculpin (Cottus beldingi), the only other similar sculpin species within its range, by medial chin pores and anal fin rays. The margined sculpin has one chin pore and 14 to 17 anal rays while the piute sculpin has two chin pores and 11 to 14 anal rays.

The former range of C. marginatus is unknown. Currently it is found in the Blue Mountains of Oregon and Washington. In Washington it is only found in parts of the Tucannon and Walla Walla drainages.

Margined sculpin spawn in the spring. They likely spawn under rocks in pools at temperatures that range from 11.5^o C to 16^o C. Young-of-the-year margined sculpin appear in electrofishing surveys during the fall.

Fish species diversity within the range of C. marginatus is low and it is not understood how they interact. It is known that different species of sculpins are preyed upon by fish, birds and mammals, while they prey upon fish eggs and other small fish including salmon.

The margined sculpin is primarily a pool dweller in streams. Its preference for pools does not appear to be strongly affected by seasons. It is normally found in water temperatures less than 20^o C and adults tend to be found in deeper, faster water than juveniles.

The past and current population status of the margined sculpin is unknown. However, it is locally common. Even if present populations are healthy, its extremely restricted distribution poses concern for the future. Local disturbances may have profound effects on its persistence.

Most of the waters inhabited by C. marginatus have degraded habitat. Problems are caused by development, logging, agriculture, grazing and channelization. These activities result in sedimentation of substrate, elevated water temperatures, algal blooms and reduction in pool habitat. Agricultural and yard chemicals not used properly can directly eliminate fish as well as cause indirect problems such as algal blooms.

The future is somewhat hopeful. The chinook salmon (Oncorhynchus tshawytscha), steelhead trout (Oncorhynchus mykiss) and bull trout (salvelinus confluentus) that inhabit the Tucannon and Walla Walla drainages have been listed as threatened under the federal Endangered Species Act. This requires that many habitat protection measures be implemented that would also likely benefit margined sculpin.

The margined sculpin is confined to an extremely small range worldwide and in Washington. Much of the habitat it dwells in is degraded with an uncertain future. Because of its small range and degraded habitat conditions it is vulnerable and likely to become threatened or endangered in a significant portion of its range without cooperative management. The Department therefore recommends that the margined sculpin be listed as a sensitive species in Washington.