17856

2003 017 00 INTEGRATED STATUS & EFFECTIVENESS MONITORING

5/1/2004

9/30/2005

157. Collect/Generate/Validate Field and Lab Data

Work Element Usage Report

E: 157 - Sampling in fish-bearing habitat

Because the macroinvertebrate community downstream of headwater junctions is likely to be affected by input of nutrients and the downstream drift of species with different taxonomic or ecological classifications than are found in the mainstem, we will sample drifting and benthic invertebrates in fish-bearing streams to determine the strength and spatial pattern of headwater stream delivery. We will deploy 4-6 drift nets of the same size used in headwater streams a minimum of 15 cm above the stream bottom for 24 hr in conjunction with the sampling of headwater streams. When practical, benthic macroinvertebrates will also be collected with a Hess sampler at the junction of the mainstem and 50-m upstream and downstream of the junction within the mainstem to assess the effects of headwater inputs on the lower trophic levels of these fish-bearing food webs.
Fish will be captured with baited Gee minnow traps, electrofishing when necessary, and by seining in pools within 50-m downstream of the zone of contact between the fishless and fish-bearing habitats (headwater ‘treatment'), and in pools within 50-m upstream of this zone (control), for determining fish responses (including possibly diet) resulting from prey delivery from the headwater tributaries. Because we will likely encounter ESA-listed anadromous salmonids such as spring chinook salmon (Oncorhynchus tshawytscha) and steelhead (O. mykiss), we will use the most passive methods possible to estimate fish population size after obtaining the necessary permissions. Removal methods using minnow traps are much less harmful than electrofishing and impart less mechanical stress to fish than seining. With a careful sampling protocol, removal sampling with minnow traps can estimate fish density in a short (~ 1 d) time period (Bryant 2000). All captured fish will be placed in buckets of fresh stream water and monitored constantly until being returned alive to the stream. Additional estimates of fish population size will be made by snorkeling during both daytime and evening hours to account for variation in fish activity. We will conduct additional sampling of fish at pools 100 m and 150 m downstream to gain further information on the spatial extent of any effects generated by prey and nutrient input from headwater streams.
In order to link the relative contribution of invertebrate-based food webs found in the headwater streams and that of the fish-bearing streams to the condition of relevant fish populations, we must use some direct measures of fish responses to differences in food availability. Analysis of fish diet, condition and behavior will enable us to establish how strongly connected the energetic inputs of headwater streams are to the persistence of resident and anadromous species. During regular sampling of fish at our study sites we will anesthetize individuals of all species with MS-222® and use gastric lavage techniques (Meehan and Miller 1978) to obtain a sample of consumed prey. Although somewhat invasive, Meehan and Miller (1978) obtained high survival rates and pilot studies on hatchery-derived juvenile coho salmon (O. kisutch) in our study system resulted in full recovery with no immediate mortality (Polivka unpubl. data). Following sample collection and preservation, gut contents will be analyzed in the laboratory to determine whether the assemblage of taxa consumed by fish can be linked to either headwater or mainstem production.
Foraging behavior of actively foraging drift-feeding anadromous salmonids will be quantified in the field by a single observer using focal animal surveys (Altmann 1974) in stream pools or other occupied microhabitat patches. Observations will generally not be conducted for benthic sit-and-wait foragers such as sculpins. For each fish observed, the number of foraging attempts per minute will be recorded for a thirty minute period or until the individual quits foraging in the given patch, whichever comes first. Patch residence times of shorter duration than 30 min. will be documented. Additionally, the number and identity of other individuals foraging in the patch will be recorded as will aggressive behaviors such as displays, nips, and chases between individuals. Physical dimensions of the patch will be measured and productivity estimated from drift samples described above to determine mechanistic relationships between fish production and the carrying capacity of stream reaches. Foraging theory predicts that productivity is an important determinant of group size and dynamics such as residence time at the patch scale (Giraldeau and Caraco 2000) and the use of and competition for foraging patches may be an important indicator of fish carrying capacity, particularly where headwaters may contribute to productivity.

1) Peer-reviewed publications and technical reports identifying the response of fish to varying macroinvertebrate production across the four land-use/ecoregion categories.

2) Identification of conceptual approaches and associated field techniques for monitoring the effects of food availability, foraging group size, and intra- and interspecific competition on the performance of fish in areas immediately downstream of fishless low-order streams.

$31,516

22.68%

09/30/2005

Concluded

n/a

n/a

Recurring