Fish Abundance and Habitat Recommendations of the Lake Whatcom Tributaries

The tributaries of Lake Whatcom, Austin/Beaver, Anderson, Olsen, and Smith Creeks, provide essential habitat for many fish species native to the Pacific Northwest. However, development in the watershed has contributed to habitat alterations and even degradation of habitat quality. In this report, fish abundance and diversity, and habitat quality is compared both temporally, and among different streams. Anderson Creek was found to have the greatest species diversity. Cutthroat trout was the most abundant fish at each stream throughout the study period and was observed at every study site. Restoration recommendations for each stream were aimed at supporting existing native fish populations primarily by improving bank stability and restoring riparian zones. Future management plans should take into account the current and historical fish populations in the watershed and consider the recommendations identified within this report. Introduction The Lake Whatcom Watershed, located in Whatcom County of Washington state, is the primary source of drinking water for the county and consists of a large area of native fish habitat. All of the tributaries in the Lake Whatcom watershed have been subject to varying levels of anthropogenic influences, particularly from housing development. For example, the Austin/Beaver Creek basin has undergone vast disturbances since the development of Sudden Valley, establishing 5,000 residents along with roads and a golf course, beginning in 1969 (Smith 2009). The Olsen Creek watershed on the other hand, has experienced minimal housing development compared to the other tributaries, and is partially owned and protected by the city of Bellingham and the Department of Natural Resources (Olsen Creek Preserve, 2016). As future plans for development, restoration, and watershed management are considered for the Lake Whatcom watershed, it is important to consider the past and current habitat quality of these tributaries. Lake Whatcom and its tributaries host a variety of fishes native to the Pacific Northwest, including Cutthroat trout (Oncorhynchus clarkii) and Prickly sculpin (Cottus asper). Native runs of Kokanee (Oncorhynchus nerka) are also present, although greatly depleted in recent years, in Olsen, Anderson, and Smith Creeks (Fish Distribution and Periodicity, 2001). Historically, Kokanee have also been stocked in the watershed by the Brannian Creek state fish hatchery, located at the south end of the lake. Habitat quality of the tributaries is of particular concern for adfluvial species, such as Cutthroat trout and Kokanee, who utilize upper and lower stretches of their home streams. This report focuses on the four main tributaries of Lake Whatcom, Smith, Olsen, Austin/Beaver, and Anderson Creeks. Beaver Creek converges with Austin Creek before flowing into the southwest side of the lake, Anderson Creek drains into the south end, and Smith and Olsen Creeks are situated on the northeast side of the lake (Figure 1). Figure 1. Lake Whatcom basin, showing where the tributaries drain into the lake. Sample sites are located at each star.