Long‐term changes in the abundance of <i>Jesogammarus annandalei</i> (Tattersall) in Lake Biwa

Ishikawa, Toshiyuki; Narita, Toshio; Urabe, Jotaro

doi:10.4319/lo.2004.49.5.1840

Cited by 17 publications

(19 citation statements)

References 25 publications

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“…This value means that $4.5 g O 2 m À3 was consumed in the deep layer with 25 m of thickness if RQ=1. In agreement with this estimate, $4-6 g O 2 m À3 has been consumed every year during the thermally stratified period at deep depths in Lake Biwa since 1970 (i.e., Ishikawa et al 2004). Thus, although the carbon mineralization rate is much lower in the deep layer compared with the surface layer, further increases in the rate would result in serious impacts on the chemical environments at deep depths in Lake Biwa (see also Murase et al 2005).…”

Section: Discussionsupporting

confidence: 59%

The production‐to‐respiration ratio and its implication in Lake Biwa, Japan

Urabe

Yoshida

Gurung

et al. 2005

Ecological Research

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Production-to-respiration (P:R) ratio was estimated at an offshore site of Lake Biwa in order to examine whether the plankton and benthic community is subsidized with allochthonous organic carbon, and to clarify the role of this lake as potential source or sink of carbon dioxide. The respiration rate of protozoan and metazoan plankton was calculated from their biomass and empirical equations of oxygen consumption rates, and that of bacterioplankton was derived from their production rate and growth efficiency. In addition, the carbon mineralization rate in the lake sediments was estimated from the accumulation rate of organic carbon, which was determined using a 210 Pb dating technique. On an annual basis, the sum of respiration rates of heterotrophic plankton was comparable to net primary production rate measured by the 13 C method. However, when the mineralization rate in the lake sediments was included, the areal P:R ratio was 0.89, suggesting that Lake Biwa is net heterotrophic at the offshore site with the community being subsidized with allochthonous organic carbon. Such a view was supported by the surface water pCO 2 that was on average higher than that of the atmosphere. However, the estimate of net CO 2 release rate was close to that of carbon burial rate in the sediments. The result suggests that the role of Lake Biwa in relation to atmospheric carbon is almost null at the offshore site, although the community is supported partially by organic carbon released from the surrounding areas.

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Section: Discussionsupporting

confidence: 59%

The production‐to‐respiration ratio and its implication in Lake Biwa, Japan

Urabe

Yoshida

Gurung

et al. 2005

Ecological Research

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“…At the same time, gammarids ( Jesogammarus annandalei ), another common prey of G. isaza [25], suddenly increased in population density through release from top-down regulation by G. isaza (Fig. 1d; also see [32]). …”

Section: Introductionmentioning

confidence: 98%

“…Intriguingly, G. isaza has adapted to a pelagic habitat with its strong swimming ability, whereas most gobiid fish are benthic. As a result of this strong swimming ability, this species plays important roles in the lake ecosystem as a keystone predator by feeding on pelagic zooplankton and benthic gammarid amphipods [25], [32], thereby coupling the pelagic and benthic food webs of the lake. Through stomach content analysis, Nakanishi and Nagoshi [25] reported that G. isaza fed mainly on zooplankton and gammarids in the 1960s.…”

Section: Introductionmentioning

confidence: 99%

Long-Term Changes in the Diet of Gymnogobius isaza from Lake Biwa, Japan: Effects of Body Size and Environmental Prey Availability

et al. 2012

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Body size and environmental prey availability are both key factors determining feeding habits of gape-limited fish predators. However, our understanding of their interactive or relative effects is still limited. In this study, we performed quantitative dietary analysis of different body sizes of goby (Gymnogobius isaza) specimens collected from Lake Biwa between 1962 and 2004. First, we report that the diet was composed mainly of zooplankton (cladocerans and copepods) before the 1980s, and thereafter, shifted to zoobenthos (gammarids). This foraging shift coincided with, and thus can be linked to, known historical events in the lake at that time: decrease in zooplankton abundance with the alleviation of eutrophication, increase in fish body size resulting from fish population collapse, and increase in gammarid abundance due to reduced fish predation pressure. Supporting this view, our data analyses revealed how the long-term changes in the diet composition would be co-mediated by changes in fish body size and environmental prey availability. Specifically, while zoobenthos abundance strongly affected the fish diet composition, larger (smaller) fish preferred zoobenthos (zooplankton). Furthermore, the body size effects were stronger than those of prey availability. These results provide the best long-term evidence that fish feeding habits vary over decades with its body size and prey community due to anthropogenic disturbances.

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“…To test this hypothesis, Tsai et al (2016) reanalyzed long-term dietary data for an omnivorous predatory fish species collected from a lake ecosystem over four decades (Briones et al 2012) by incorporating environmental abundance data for its major prey, zooplankton and zoobenthos (Ishikawa et al 2004;Hsieh et al 2011). Specifically, they compared prey size compositions in predator guts and the environment (i.e., the realized versus the environmental PPMR) to detect deviations between these elements as effects of the preferred PPMR.…”

Section: Realized Versus Preferred Predator-prey Mass Ratiomentioning

confidence: 99%

Individual interaction data are required in community ecology: a conceptual review of the predator–prey mass ratio and more

Nakazawa

2016

Ecological Research

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Community ecology is traditionally speciesbased and assumes that species comprise identical individuals. However, intraspecific variation is ubiquitous in nature because of ontogenetic growth and critical in food-we dynamics. To understand individual interaction-mediated food webs, researchers have recently focused on body size as the most fundamental biological aspect and assessed a parameter called the predatorprey mass ratio (PPMR). Herein, I review the conceptual development of the PPMR and suggest four major concerns regarding its measurement: (1) PPMR should be measured at the individual level because species-averaged values distort actual feeding relationships, (2) individual-level PPMR data on gape-unconstrained predators (e.g., terrestrial carnivores) are limited because previous studies have targeted gape-limited fish predators, (3) predators' prey size selectivity (preferred PPRM) is conceptually different from dietary prey size (realized PPMR) and should be distinguished by incorporating environmental prey abundance information, and (4) determinants of preferred PPMR, rather than those of realized PPMR, should be identified to describe size-dependent predation. Future studies are encouraged to explore not only predation but also other interaction types (e.g., competition, mutualism, and herbivory) at the individual level. However, this is not likely to occur while ecological communities are still considered to be interspecific interaction networks. To resolve this situation and more comprehensively understand biodiversity and ecosystem functioning, I suggest that community ecology requires a paradigm shift in the unit of interaction from species to individuals, similar to evolutionary biology, which revolutionized the unit of selection, because interactions occur between individuals.

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Long‐term changes in the abundance of Jesogammarus annandalei (Tattersall) in Lake Biwa

Cited by 17 publications

References 25 publications

The production‐to‐respiration ratio and its implication in Lake Biwa, Japan

The production‐to‐respiration ratio and its implication in Lake Biwa, Japan

Long-Term Changes in the Diet of Gymnogobius isaza from Lake Biwa, Japan: Effects of Body Size and Environmental Prey Availability

Individual interaction data are required in community ecology: a conceptual review of the predator–prey mass ratio and more

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