Scholarlink

<p>Warming freshwaters can have profound effects on species composition and community structure and can increase the consumptive demand of predators. Here we explore synergistic impacts of warming and invasion within a freshwater community in Southcentral Alaska (USA). We quantified changes in population structure and predator diet composition using observed data for an introduced population of Northern Pike (<i>Esox lucius</i>) spanning a decade of warming temperatures and declining salmon returns. We used bioenergetics models to estimate past and contemporary predator consumptive demands and then estimated future consumption demands by applying forecasted future simulated temperatures under high emissions scenarios for the mid and late century compared to a baseline from the last twenty years. During the last decade, the population structure of Northern Pike shifted towards younger individuals with increased growth rates in young of year and Age-1 fish. The biomass of juvenile salmon in Northern Pike diets decreased 30–74% across all age classes of predators, corresponding to a 42% reduction of mean abundance of adult Chinook Salmon (<i>Oncorhynchus tshawytscha</i>) in the system from 2014–2018 to 2019–2023. Consumption of all fish species was highly variable and all increased, 5% to 63%, consistent with prey switching towards other fishes reflecting possible declines in availability of preferred salmon prey. Bioenergetic simulations revealed modest increases in total per-capita consumption of prey by Northern Pike across mid-century and late-century scenarios, with the largest increases in consumption predicted in individuals three years of age and greater. We also observed increased numbers of Coho Salmon (<i>Oncorhynchus kisutch</i>) in diets and smaller mean size suggesting a shift to young of year individuals as well as an absence of Sockeye Salmon (<i>Oncorhynchus nerka</i>) from diets, which differed from historical baseline data. These findings collectively suggest that changing thermal regimes may have modest but meaningful overall effects, disproportionately affecting the consumptive demands of larger Northern Pike, and may increase total consumption enough to appreciably increase mortality of salmon and other preferred prey.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Warming causes modest increase in the consumptive demands of invasive Northern Pike (Esox lucius) in Alaska freshwaters

  • 期刊论文

  • 发表日期：

    2026年2月13日

查看全文
  • Benjamin A. Rich,
  • Adam Sepulveda,
  • Daniel Rinella,
  • Jeffrey Falke,
  • Erik Schoen,
  • Peter Westley

摘要

Warming freshwaters can have profound effects on species composition and community structure and can increase the consumptive demand of predators. Here we explore synergistic impacts of warming and invasion within a freshwater community in Southcentral Alaska (USA). We quantified changes in population structure and predator diet composition using observed data for an introduced population of Northern Pike (Esox lucius) spanning a decade of warming temperatures and declining salmon returns. We used bioenergetics models to estimate past and contemporary predator consumptive demands and then estimated future consumption demands by applying forecasted future simulated temperatures under high emissions scenarios for the mid and late century compared to a baseline from the last twenty years. During the last decade, the population structure of Northern Pike shifted towards younger individuals with increased growth rates in young of year and Age-1 fish. The biomass of juvenile salmon in Northern Pike diets decreased 30–74% across all age classes of predators, corresponding to a 42% reduction of mean abundance of adult Chinook Salmon (Oncorhynchus tshawytscha) in the system from 2014–2018 to 2019–2023. Consumption of all fish species was highly variable and all increased, 5% to 63%, consistent with prey switching towards other fishes reflecting possible declines in availability of preferred salmon prey. Bioenergetic simulations revealed modest increases in total per-capita consumption of prey by Northern Pike across mid-century and late-century scenarios, with the largest increases in consumption predicted in individuals three years of age and greater. We also observed increased numbers of Coho Salmon (Oncorhynchus kisutch) in diets and smaller mean size suggesting a shift to young of year individuals as well as an absence of Sockeye Salmon (Oncorhynchus nerka) from diets, which differed from historical baseline data. These findings collectively suggest that changing thermal regimes may have modest but meaningful overall effects, disproportionately affecting the consumptive demands of larger Northern Pike, and may increase total consumption enough to appreciably increase mortality of salmon and other preferred prey.