The Role of Predation in Age‐ and Size‐Related Habitat Use by Stream Fishes

Abstract

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org. Abstract.I examined the effects of age and body size on intra-and interspecific habitat relationships for 15 species of fishes in a natural second-order warm water stream. Juveniles (age 0) of all taxa and adults (>age 0) of taxa with small maximum body size (darters and cyprinids) were at high densities predominantly in shallow riffle and raceway habitats. Adults of taxa with large maximum body size (catastomids and centrarchids) were at low densities predominantly in deep pool habitats. Based on the complementarity in depth distribution of large and small fishes, controlled experiments were conducted in a seminatural experimental stream to assess (1) the effect of large centrarchid piscivores in pools on the habitat use of small fishes, (2) the influence of structural complexity of pool habitats on the interaction between centrarchid predators and their prey, and (3) the effectiveness of centrarchid predators at capturing small fishes when shallow refugia exist. In the ex? periments, juvenile hornyhead chub, white sucker, and smallmouth bass were allowed to select one of four physical habitats in the presence and absence of adult smallmouth bass: riffle, raceway, structurally simple pool, or structurally complex pool. Predators were re? stricted to pool habitats so that riffles and raceways were effective refugia. Predation by bass occurred even though effective refugia were present. However, the taxa exhibited considerable variation in susceptibility to predation; white suckers were most vulnerable and smallmouth bass least vulnerable. In the absence of bass, juveniles of all taxa preferred structurally complex or structurally simple pools, even though benthic insect densities were higher in riffles than pools. In the presence of bass, juveniles of all taxa were largely restricted to shallow riffle or raceway refugia, with the extent of the shift in distribution to shallow habitats related to the vulnerability ofthe taxa to predation. If juvenile fishes occurred in pools with centrarchid predators, juveniles were at low densities and only in pools with high structural complexity. These results suggest that the high density and extensive overlap in habitat use of small fishes in shallow habitats of small warm water streams is related to the increased risk of predation by centrarchids in pools.

Nature and Functions of Cover for Riverine Fish.

“…Pêche Piscic. (2002) 365/366 : 297-324 the highest risk of predation in shallow habitats is for large fish, due to non-gape limited predators (birds and mammals) whereas in deeper habitats it is for small fish from gapelimited, piscivorous fish (POWER, 1987;SCHLOSSER, 1987). Some laboratory and field experimental studies have clearly demonstrated that terrestrial predation risk from wading/diving animals is much higher for water-column species in shallow pools than in deep pools and added cover markedly increases their survival (HARVEY and STEWART, 1991;LONZARICH and QUINN, 1995;REINHARDT and HEALEY, 1997).…”

“…Species richness increases with watershed size (GUÉGAN et al, 1998) and at the local scale with habitat diversity (GORMAN and KARR, 1978;SCHLOSSER, 1982SCHLOSSER, , 1985SCHLOSSER, , 1987. Numerous studies, mainly dealing with the association of upland stream salmonid assemblages with woody debris, revealed the importance of cover as a key factor governing fish distribution (BOUSSU, 1954;GRANDMOTTET, 1983;ANGERMEIER and KARR, 1984).…”

Use of Ecohydraulic-Based Mesohabitat Classification and Fish Species Traits for Stream Restoration Design

“…The greatest richness and density occurred during the summer and fall periods, with a total of 23 species and average unit densities ranging from 4.9 to 218.6 fish per 100 m 2 . Others found the same seasonal patterns of use where feeding, resting, evasion from predation, and spawning were the dominant trait strategies [172,178,179,193,194,197,198,201,203,[214][215][216]. Schwartz and Herricks (2008) [79] found that feeding strategy could be summarized as: insectivores mainly occupying the pool-front unit, omnivores in the scour pool unit, piscivores in the pool-mid unit, and herbivores in the glide and riffle with raceway unit.…”

“…Within the mesohabitat scale, differential habitat use by fish between pools and riffles has been extensively studied [77,123,175,[193][194][195][196][197][198][199]. It was observed from these studies that pools and riffles locally diversify lotic conditions providing strong abiotic environmental controls on fish distribution and abundance.…”

“…In the Midwest US for example, centrarchid species occupy pools and darter species will occupy riffles [179,197]. Spatial segregation by fish between pool and riffle habitats is also influenced by several biotic factors including predator-prey interactions [194,201], interspecific competition or aggression [202,203], differential body size and body morphology related to energetics of maintaining position in different hydraulic conditions [78,200,204], and innate habitat preferences. Riffles and lateral shallow areas such as submerged point bars provide cover for smaller fish from larger predatory fish [205,206].…”