Prey availability and diet of juvenile brown trout (<i>Salmo trutta</i>) in relation to riparian willows (<i>Salix‐</i>spp.) in three New Zealand streams

Sagar, P. M.; Glova, G. J.

doi:10.1080/00288330.1995.9516685

Cited by 39 publications

(32 citation statements)

References 23 publications

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“…The present study also found broad variation in the feeding patterns of brown trout on a seasonal basis across several streams and demonstrated that prey selection was not proportional to the environmental density of macroinvertebrates, similar to other studies (Sagar and Glova 1995;MacNeil et al 2000;Crespin De Billy and UsseglioÀPolatera 2002). Brown trout are visual feeders, thus prey preference and capture probability are likely influenced by the accessibility, size, color, mobility, and degree of exposure of various prey types (Rader 1997;Crespin De Billy and UsseglioÀPolatera 2002).…”

Section: Broad Patternssupporting

confidence: 72%

Seasonal feeding selectivity of brown trout Salmo trutta in five groundwater-dominated streams

Cochran-Biederman

Vondracek

2017

Journal of Freshwater Ecology

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Availability and selection of macroinvertebrate prey is important to explain temporal and spatial variation in growth among stream salmonids. However, few studies contain information to identify such relationships. Our objectives were to quantify drift and benthic macroinvertebrate prey availability and selection by brown trout on a seasonal basis in five streams across three years in southeastern Minnesota. Few taxa were dominant in diets and the environment with considerable variability in drifting and benthic prey within streams and seasons. Brown trout consistently selected only one or two taxa, and displayed neutral or negative selection for other taxa. In general, large-bodied, energy-rich benthic prey were selected over other more abundant aquatic macroinvertebrate taxa and drifting prey. Foraging patterns suggested a preference of benthic feeding. Electivity of benthos and drift varied spatially and temporally with a negative relationship between the total proportion of prey available and prey electivity. In general, seasonal growth and prey electivity were not related across all streams, but were positively related within two of five streams. Understanding seasonal and spatial relationships among growth, prey availability, and prey selection may aid future management of streams, as climate change is expected to alter physical conditions and biological communities of streams.

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Section: Broad Patternssupporting

confidence: 72%

Seasonal feeding selectivity of brown trout Salmo trutta in five groundwater-dominated streams

Cochran-Biederman

Vondracek

2017

Journal of Freshwater Ecology

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“…The effect of gut passage on later survival and reproductive potential of snails was not assessed in my study, but shells of live egested snails were observed to be undamaged. These results, combined with molluscs often being a minor component of trout diets (McCarter 1986;Sagar & Glova 1995), suggest trout are weak regulators of Potamopyrgus populations. In New Zealand, some native fishes may exert strong lethal effects on Potamopyrgus, such as bullies that commonly eat these snails (Rowe & Chisnall 1996) and do not pass them live (Holomuzki & Biggs 2006).…”

Section: Discussionmentioning

confidence: 93%

“…Clearly, both Potamopyrgus and Physella are eaten by brown trout (McCarter 1986;Sagar & Glova 1995;Kristensen & Closs 2008), introduced mainly from Europe c. 1880 and now widely abundant in New Zealand streams and lakes (McDowall 1990 (10.190.4 cm FL) and eight fish at ageÂ20 months (29.490.7 cm FL) were collected to compare snail consumption patterns between age classes. Immediately after capture, fish were placed in 12 or 16 white plastic tubs (each 80)43)22 cm high), depending on year.…”

Section: Introductionmentioning

confidence: 99%

Within-reach spatial variability of snails and molluscivory by brown trout

Holomuzki

2010

New Zealand Journal of Marine and Freshwater Research

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Linking habitat distributions of prey to the probability of predation is important to understanding consumptive effects of predators on prey populations. This study reports how within-reach spatial variability of two snails, the hydrobiid Potamopyrgus antipodarum and the physid Physella acuta, was linked to habitat-based predation risk by young brown trout (Salmo trutta) of different age classes. Potamopyrgus is endemic to New Zealand streams and lakes, where it commonly co-exists with the invader P. acuta, but both snails are worldwide invaders to many freshwater systems. Examination of egested snails revealed Potamopyrgus and Physella were consumed in similar numbers within age classes. However, 10-month-old trout consumed, on average, fewer snails than 20-month-old trout, and 8-month-old trout ate essentially no snails, suggesting snails were a more important prey item for larger age-1 fish than smaller age-0 fish. No Physella were egested alive by any trout age class. However, 38% and 16% of the Potamopyrgus consumed were egested alive by 10-and 20-month-old trout, respectively, with some passing live afterÂ70 h in digestive tracts. Physella and the spiny-shell form of Potamopyrgus were significantly denser on macrophytes than on stony sediments in midchannel, and these habitat distributions affected their odds of consumption. Risk of consumption by trout was Â10 times greater for Physella than Potamopyrgus on stones, but their risk was similar in protective macrophytes. Odds of consumption were similar for spiny and smooth shell forms of Potamopyrgus on stones, suggesting spines do not provide protection from large predators like trout. My results suggest that brown trout can potentially exert stronger population regulatory effects on Physella than on Potamopyrgus and that these effects are partly mediated by macrophyte cover.

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“…These groups also dominate drift communities in other New Zealand rivers ( & Glova 1992), and species in these orders are important in the diets of drift-feeding fish (Dedual & Collier 1995;Sagar & Glova 1995). Similarly, these groups have been shown to be important drifting orders in international studies (Elliott 1967b;Radford & Hartland-Rowe 1971;Brittain & Eikeland 1988;Mathooko & Mavuti 1992;.…”

Section: Comparison Of Taxonomic Compositionmentioning

confidence: 99%

Relationships between drifting and benthic invertebrates in three New Zealand rivers: Implications for drift‐feeding fish

Shearer¹,

Stark

Hayes

et al. 2003

New Zealand Journal of Marine and Freshwater Research

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We assessed whether taxonomic structure and density of aquatic drift could be predicted from the benthos in three New Zealand rivers. The three main orders contributing to both the benthos and drift were Ephemeroptera, Diptera, and Trichoptera. Drift and benthic densities for all taxa and all rivers combined were not significantly correlated (adults inclusive and exclusive). There were significant positive correlations between benthic and drift densities for the three main drifting orders-Ephemeroptera, Diptera, and Trichoptera when data from all rivers were combined. However, these relationships were not always detected in individual rivers. The propensity for Deleatidium to drift was negatively related to chlorophyll a concentration; suggesting density-dependent drift mediated by food limitation. Drift was reduced when periphyton chlorophyll a concentration was high in relation to benthic Deleatidium density. This highlights an unexpected effect of periphyton proliferation on invertebrate drift and drift-feeding fishes. Despite finding some correlations between benthic and drifting communities, defining general relationships between benthic and drifting communities is challenging given the complexity of density-dependent and densityindependent mechanisms that influence invertebrate drift.

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Prey availability and diet of juvenile brown trout (Salmo trutta) in relation to riparian willows (Salix‐spp.) in three New Zealand streams

Cited by 39 publications

References 23 publications

Seasonal feeding selectivity of brown trout Salmo trutta in five groundwater-dominated streams

Seasonal feeding selectivity of brown trout Salmo trutta in five groundwater-dominated streams

Within-reach spatial variability of snails and molluscivory by brown trout

Relationships between drifting and benthic invertebrates in three New Zealand rivers: Implications for drift‐feeding fish

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