Larval lamprey distribution and habitat use in small stream channels on the Oregon coast. Starcevich, S., J. & Clements, S., P. Technical Report
Larval lamprey distribution and habitat use in small stream channels on the Oregon coast [pdf]Paper  Larval lamprey distribution and habitat use in small stream channels on the Oregon coast [link]Website  abstract   bibtex   5 downloads  
Potential fish passage barriers have been identified in over 4,100 small streams (i.e., <8 m wide) in coastal Oregon basins from the Nehalem River south to the Coos River and may be blocking Pacific lamprey access to spawning and rearing habitat. The impact of these barriers is unknown because of a lack of information on how Pacific lampreys use these small stream habitats. We conducted a pilot study using multi-state occupancy modeling to better understand distribution, habitat use, and sampling detection of larval Pacific lampreys in small streams to improve monitoring techniques and begin to evaluate the effect of barriers on lampreys in the Coastal Oregon Province. Electrofishing surveys were conducted by a two-person field crew from July through October, 2012. Sampling occurred in two small wilderness basins and streams in the Siuslaw, Umpqua, and Coos river basins. Streams channels ranged from 0.8 to 20 m wetted width and contained no known barriers to upstream migratory fish passage. Pacific lamprey larvae occupied all streams in the sample frame and overlapped substantially with Western brook lamprey in longitudinal distribution patterns. Detection probability of larvae in the low abundance state was high (p1) = 0.85) fast-water units and were rarely detected in high abundance in fast-water units. Pacific larvae were more abundant and occupied a greater proportion of the sample sites compared to Western brook larvae. Pacific lamprey larvae were detected in stream channels as small as 4 m wide. Larval occupancy and detection estimates obtained in this study are useful for designing future studies. Several improvements to the study design will lead to more precise estimates and greater scope of inference in continued research into larval distribution in small stream channels. =0.85). Larvae in general were more likely to occupy pools than

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