Longitudinal Differences in Brook Trout Density and Mean Length in Headwater Streams of Western Massachusetts

摘要: Brook trout (Salvelinus fontinalis) face many threats throughout their native range in the eastern United States including climate change, invasive species, and recreational angling. Understanding habitat requirements distribution of young year adult brook small headwater streams is essential for conservation species. With this research, we sought to better understand pattern year, detect seasonal movement adults before during spawning season, determine if preferentially inhabit stream reaches different sizes. To explore these fishhabitat relationships, electrofished 30 meter with catchment areas ranging from 0.09 km 4.90 systems two western Massachusetts watersheds. Sampling was conducted spring fall 2014. We used generalized linear mixed models evaluate density density, mean length all fish sampled. The results indicate that quadratic or increases size. found no differences densities. also did not find a longitudinal difference length. These lead us believe sizes included study are equally important persistence should be considered priorities. This demonstrated need additional research upper since our explain significant proportion variability data. Additional landscape variables measured how population dynamics vary longitudinally managed future. Introduction: stream-dwelling Eastern States. depend on cold, oxygenated water suitable have narrow thermal limit (10-19°C: Hillman et al. 1999), thus likely impacted negatively by increasing temperatures associated change. In addition decreased availability due warming waters, distributions warmer species such as smallmouth bass (Micropterus dolomieu), brown (Salmo trutta), rainbow (Oncorhynchus mykiss) shifting upstream putting pressure (EBTJV 2006). Populations declining over much isolated headwaters (Hudy 2008). populations particularly vulnerable degradation changes connectivity (Mollenhauer 2013). It distributed use longitudinally. Although considerable has