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Data from: Benefits of turbid river plume habitat for Lake Erie yellow perch (Perca flavescens) recruitment determined by juvenile to larval genotype assignment
Carreon-Martinez, Lucia B.; Walter, Ryan P.; Johnson, Timothy B.; Ludsin, Stuart A.; Heath, Daniel D. — 2016-04-09 Nutrient-rich, turbid river plumes that are common to large lakes and coastal marine ecosystems have been hypothesized to benefit survival of fish during early life stages by increasing food availability and (or) reducing vulnerability to visual predators. However, evidence that river plumes truly benefit the recruitment process remains meager for both freshwater and marine fishes. Here, we use genotype assignment between juvenile and larval yellow perch (Perca flavescens) from western Lake Erie to estimate and compare recruitment to the age-0 juvenile stage for larvae residing inside the highly turbid, south-shore Maumee River plume versus those occupying the less turbid, more northerly Detroit River plume. Bayesian genotype assignment of a mixed assemblage of juvenile (age-0) yellow perch to putative larval source populations established that recruitment of larvae was higher from the turbid Maumee River plume than for the less turbid Detroit River plume during 2006 and 2007, but not in 2008. Our findings add to the growing evidence that turbid river plumes can indeed enhance survival of fish larvae to recruited life stages, and also demonstrate how novel population genetic analyses of early life stages can contribute to determining critical early life stage processes in the fish recruitment process.
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Data from: Pop‐off data storage tags reveal niche partitioning between native and non‐native predators in a novel ecosystem
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Raby, Graham D.; Johnson, Timothy B.; Kessel, Steven T.; Stewart, Thomas J.; Fisk, Aaron T. — 2022-04-26 1. Niche partitioning might be predicted to be particularly dynamic in ‘novel ecosystems’ characterized by human-altered environmental conditions and biological invasions. Restoration efforts for native species in such systems can be informed by detailed characterization of niche partitioning. 2. In Lake Ontario, fishery management agencies have been engaged in a long-term struggle to restore native top predators including lake trout (Salvelinus namaycush). Meanwhile, management agencies continue to stock non-native species like Chinook salmon (Oncorhynchus tshawytscha) into the lake to support a recreational fishery and to help control the abundance of a non-native forage fish, the alewife (Alosa pseudoharengus). 3. We used pop-off data storage tags to study fine scale (9.1M lines of data from 22 animals) behaviour and habitat use by lake trout (native) and Chinook salmon (non-native) in Lake Ontario in terms of depth and temperature, recorded at ≤70 s intervals for periods of up to 12 months. 4. Chinook salmon occupied warmer and shallower waters during summer than did lake trout, and their niche breadth was wider. They achieved greater niche breadth in part because they were much more active vertically, cumulatively traveling 103±1 m hour-1 during summer (model-estimated median), whereas most lake trout were relatively inactive vertically (7±1 m hour-1). In each of our analyses, there was more inter-individual variation among lake trout than among Chinook salmon, driven by some lake trout that spent considerable time making forays into warmer, shallower waters. 5. Synthesis and applications. Our results illustrate the different foraging tactics used by two species in the Great Lakes and reflect their distinct life histories. Vertical and thermal niche partitioning between Chinook salmon and lake trout helps to explain how these species can co-exist in a multi-species fishery even while having substantial overlap in diet. The diversity of behaviours exhibited here by native lake trout have likely helped them persist during dramatic changes to the forage base in recent decades; that flexibility could help underlie their long-term prospects for restoration during future changes to the ecosystem.
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Telemetry data from: Realized thermal niche approach eliminates temperature bias in 3 bioenergetic model estimates
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Ivanova, Silviya V.; Fisk, Aaron T.; Johnson, Timothy B. — 2023-12-04 Raw data for Ivanova et al paper in Ecology and Evolution Datafile is an .rds file. Abstract: Bioenergetics models estimate ectotherm growth, production, and prey consumption – all key for effective ecosystem management during changing global temperatures. Based on species-specific allometric and thermodynamic relationships these models typically use the species' lab-derived optimum temperatures (physiological optimum) as opposed to empirical field data (realized thermal niche) that reflect actual thermal experience. Yet, dynamic behavioural thermoregulation mediated by biotic and abiotic interactions may provide substantial divergence between physiological optimum and realized thermal niche temperatures to significantly bias model outcomes. Here, using the Wisconsin bioenergetics model and in-situ year-round temperature data, we tested the two approaches and compared the maximum attainable lifetime weight and lifetime prey consumption estimates for two salmonid species with differing life-histories. We demonstrate that using the realized thermal niche is the better approach because it eliminates significant biases in estimates produced by the physiological optimum. Specifically, using the physiological optimum, slower-growing Salvelinus namaycush maximum attainable lifetime weight was underestimated, and consumption overestimated, while fast-growing Oncorhynchus tshawytscha maximum attainable weight was overestimated. While the physiological optimum approach is useful for theoretical studies, our results demonstrate the critical importance that models used by management utilize up-to-date system- and species-specific field data representing actual in-situ behaviours (i.e., realized thermal niche). https://creativecommons.org/licenses/by/4.0/legalcode

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(Author: Johnson, Timothy B.)

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