Bioenergetic calculations evaluate changes to habitat quality for salmonid fishes in streams treated with salmon carcass analog

Abstract

Nutrient supplementation in oligotrophic streams is proposed as a means of mitigating losses of marine-derived subsidies from declining or extirpated populations of anadromous fishes. One of the central predictions of nutrient addition is an increased production of fish through bottom-up increases in invertebrate abundance. Such changes in food availability may increase growth and production rates for stream fishes by increasing habitat quality. In this study we apply bioenergetic calculations to estimate changes to habitat quality based on predicted increases in net energy intake. We compared invertebrate drift abundance and estimated changes in energy availability in streams treated with salmon carcass analog versus untreated controls. Our results revealed a two-to threefold increase in invertebrate drift abundance following the addition of salmon carcass analog; however, this effect appeared to be short-term. Measures of the energetic profitability of stream habitat for salmonid fishes revealed small, yet significant, increases in net energy availability in streams that received analog additions, but only after controlling for differences in physical habitat features such as temperature and stream flow.

Evaluation of the Methodology to Assess the Influence of Hydraulic Characteristics on Habitat Quality

“…Fishes as bioindicators have been selected because of their suitability for assessing the ecological integrity of rivers, for their sensitivity to changes in river habitats, occurrence, longevity, and mobility [11,14,15]. Changing the riverbed morphology and, hence, faster water heating is a significant threat to fish, as they are ectothermic animals [16].…”

Bioenergetic Habitat Suitability Curves for Instream Flow Modeling: Introducing User‐Friendly Software and its Potential Applications

“…For example, NREI computed by the program on user-supplied depth and velocity point mea surements could be used as a rapid approximation of carrying capacity, based on the proportion of energetically profitable habitat (Wall et al 2016). Similarly, it could also be used to test or predict the effectiveness of habitat restoration efforts aimed at increasing rearing capacity, (Hafs et al 2014); (Keeley et al 2016). The potential spatial scale of these applications is only limited by the quantity of hydraulic data and computing power.…”

Fisheries Volume 45 Number 11 November 2020

“…For example, NREI computed by the program on user-supplied depth and velocity point measurements could be used as a rapid approximation of carrying capacity, based on the proportion of energetically profi table habitat (Wall et al 2016 ). Similarly, it could also be used to test or predict the effectiveness of habitat restoration efforts aimed at increasing rearing capacity, (Hafs et al 2014 ); (Keeley et al 2016 ). The potential spatial scale of these applications is only limited by the quantity of hydraulic data and computing power.…”