Characteristics of Coldwater Streams Temperature – cold Flow Variability – high but floods uncommon, close to groundwater Substrate – relatively coarse Canopy Cover / Light / Productivity – usually dark with low productivity Water Chemistry – highly variable but usually soft-water Other Fishes – few Socio-Economic Value – high

Effect of Temperature on Growth

Summer Temperature Regime

Flow Variability Spring Fed Desert Ephemeral Typical Mountain Perennial

Substrate Large Boulders are important “pool forming elements.” Clean gravel sized substrates needed for spawning.

Canopy Cover and Light Closed canopy, dark, cold, low productivity, energy derived from ALLOCHTHONOUS sources. Open canopy, light, warmer, high productivity, energy derived from AUTOCHTHONOUS sources.

Canopy Cover and Light

Water Chemistry: strongly dependent on geology Alk > 20 mg/L Alk < 5 mg/L

Brook Trout “Hot Spots” Small, Cold, Stable Flow, Clean Gravel Bed, Open-Canopy, Alkaline

Associated Species Brook Trout Mottled Sculpin Longnose Dace Blacknose Dace Northern Hognose Sucker Warpaint Shiner Fantail Darter

Northern Hognose Sucker Associated Species Small Cold Large Cold Cool Warm Brook Trout Mottled Sculpin Longnose Dace Blacknose Dace Northern Hognose Sucker Fantail Darter Warpaint Shiner

$40,000 Economic Value of Coldwater Fisheries in WV per mile of trout stream per year in economic benefit directly from angler expenditures A2n $15,000 per mile (national average)

Trout Population Dynamics Population numbers tend to be “recruitment limited” (i.e., the number of adult trout is directly dependent on the success of the recruitment class) (what is this phenomenon called?). Early spring flow regime has a strong influence on juvenile trout recruitment (high flows in spring result in poor y-o-y classes).

Trout Population Dynamics Population biomass tends to be food limited. Biomass tends to be highest in high light, highly alkaline streams.

Trout Population Dynamics Trout Production is strongly seasonal. Spring and Early Summer are the times to grow. Animals are just holding on at other times.

Trout Population Dynamics The spatial and temporal dynamics of early age classes are determined by the reproductive process. Spawning, Larval Development, Juvenile Survivorship The dynamics of adults is strongly influenced by immigration and emigration. Larger adults move around in the watershed in response to seasonal changes in habitat quality (temperature and food) and life history requirements (spawning, feeding, refuge).

Juvenile and Small Adult Distributions are Stable, but not Large Adults

Trout Population Dynamics Local Survivorship Immigration Study Sites

Large Adults Good for reproduction groundwater stable temp stable flow bed-moving flows rare safe from predators Large Adults Good for eating high light high productivity lots of small fishes

Trout Population Dynamics Mainstem High Light Tribs Low Light Tribs

What it Means Drainage Networks are the Appropriate Management Units…Not Stream Reaches Movement Barriers, Areas outside of Normal Reproductive Areas, Areas not considered “coldwater”, Fishing mortality at watershed scale.