Classification of streams and stream habitats is useful for research involving establishment of monitoring stations, determination of local impacts of land-use practices, generalization from site-specific data, and assessment of basin-wide, cumulative impacts of human activities on streams and their biota. This article presents a frame-work for a hierarchical classification system, entailing an organized view of spatial and temporal variation among and within stream systems. Stream habitat systems, defined and classified on several spatiotemporal scales, are associated with watershed geomorphic features and events. Variables selected for classification define relative long-term capacities of systems, not simply short-term states. Streams and their watershed environments are classified within the context of a regional biogeoclimatic landscape classification. The framework is a perspective that should allow more systematic interpretation and description of watershed-stream relationships.

https://faculty.washington.edu/cet6/pub/Temp/CFR521e/Frissell_etal_1986.pdf

A hierarchical framework for stream habitat classification: Viewing streams in a watershed context

Gerking (1959 Biol Rev 34: 221–242) proposed a theory about the restricted movement of stream fishes that may be considered a paradigm in salmonid biology The restricted movement paradigm (our 

Restricted Movement in Resident Stream Salmonids: A Paradigm Lost?

We constructed an energetic model to determine the optimal focal point current velocity (i.e., microhabitat) for rainbow trout (Oncorhynchus mykiss) and rosyside dace (Clinostomus funduloides) in Coweeta Creek, a fifth-order stream in North Carolina, USA. Energetic costs were evaluated by quantifying the metabolic expenditure associated with swimming at a given velocity. We estimated benefits by measuring potential energetic gains of feeding at a given velocity. This included estimates of the ability of the fish to capture prey at different current velocities as well as estimates of the frequency and the energy content of drifting prey at various velocities. We derived separate models for small (53-70 mm SL (standard length)) and medium (71-125 mm SL) trout, and medium (47- 52 mm SL) and large (53-70 mm SL) dace for all seasons, deriving net energy gain as a function of current velocity. We predicted fishes would occupy velocities at which net energy gain was maximized. Predicted velocities were compared with those utilized by fishes inhabiting Coweeta Creek. Optimal velocities predicted by energetic models ranged from 7.7 to 22.1 cm/s, and closely matched actual velocity use (average deviation = 2.6 cm/s). Prey capture success appeared to be the most important component in the models. Consequently, we constructed models based solely upon aspects of capture success; the average deviation from velocity use with these models was only 1.8 cm/s. Thus, the ability of dace and trout to capture prey at varying velocities appears to be the dominant factor affecting microhabitat selection in these species.

https://www.jstor.org/stable/info/1940796

An Energetic Model of Microhabitat Use for Rainbow Trout and Rosyside Dace

Habitat use by juvenile coho salmon Oncorhynchus kisutch, steelhead Salmo gairdneri, and the coastal subspecies of cutthroat trout Salmo clarki clarki in small streams in western Washington was influenced by hydraulic characteristics of different types of channel units. Coho salmon preferred pools with average velocities less than 20 cm/s; very few fish were found in riffles with high current velocities. Steelhead occurred in riffles and also utilized deep pools with relatively high velocities along the center of the channel. Cutthroat trout were intermediate between coho salmon and steelhead in their use of swiftly flowing habitats. Variation in body shape and fin size among the three species generally fit the predicted morphologies that would be favored in different locations within the channel. Coho salmon possessed a deep, laterally compressed body with large median and paired fins. These features are believed to facilitate rapid turns and quick but transient burst swimming. Steelhead possess...

Channel Hydraulics, Habitat Use, and Body Form of Juvenile Coho Salmon, Steelhead, and Cutthroat Trout in Streams

The interactions between dominance status, feeding rate and growth in rainbow trout, Salmo gairdneri Richardson, were analyzed using published data on experimental populations. There was a positive correlation between metabolic expenditure and food intake in both dominant and subordinate fish, but dominants obtained a greater intake for a given expenditure than did subordinates. Subordinates that adopted a high–return/high–cost foraging strategy actually expended more energy than they acquired, whereas those that minimized energy expenditure obtained a net energy gain. This led to the surprising finding that the growth rate of subordinates was negatively correlated with food intake.

Intraspecific variation in competitive ability and food intake in salmonids: consequences for energy budgets and growth rates

Increases in water temperature and fish size should increase standard metabolism and food demand. Stream-dwelling trout may then, despite the increased cost of swimming, seek faster water where food is more abundant. We tested these predictions with juvenile steelhead trout, Salmo gairdneri, in a California stream and found that increased fish size and water temperatures did result in the increased selection of microhabitats with high water velocities. Faster water provided proportionally larger amounts of drifting invertebrate food. Higher velocity, shallower, and coarser substrate microhabitats also enabled fish to capture prey from portions of the water column substantially faster and more productive than at their resting positions. Velocities selected in this stream were similar to those which would result in a doubling of metabolic rate. Models evaluating trout habitat and effects of modifications should take energetic factors into account.

Energetic factors influencing foraging tactics of juvenile steelhead trout, Salmo gairdneri

The first microsatellite loci for the endangered tidewater goby Eucyclogobius newberryi are described. A partial tidewater goby genomic library was constructed in pUC19 plasmid. Microsatellite-containing clones were isolated, sequenced, and amplified. Out of 12 positive clones sequenced, 3 were polymorphic and proved useful in a preliminary genetic screen of 3 well-separated populations (50 individuals each) along the central California coast. The number of alleles per locus ranged from 2 to 3. This initial study suggests a population bottleneck had occurred in one of the populations.

Jerry J. Smith

Papers

Energetic factors influencing foraging tactics of juvenile steelhead trout, Salmo gairdneri

Isolation and characterization of four microsatellite loci in the tidewater goby (Eucyclogobius newberryi).