scholarly journals Body size–trophic position relationships among fishes of the lower Mekong basin

2017 ◽  
Vol 4 (1) ◽  
pp. 160645 ◽  
Author(s):  
Chouly Ou ◽  
Carmen G. Montaña ◽  
Kirk O. Winemiller
Keyword(s):  
Body Size ◽  
Trophic Interactions ◽  
Fish Assemblages ◽  
Trophic Position ◽  
Isotope Analysis ◽  
The Body ◽  
Tropical Fish ◽  
Feeding Guilds ◽  
Mekong Basin ◽  
Lower Mekong Basin

Body size is frequently claimed to be a major determinant of animal trophic interactions, yet few studies have explored relationships between body size and trophic interactions in rivers, especially within the tropics. We examined relationships between body size and trophic position (TP) within fish assemblages in four lowland rivers of the Lower Mekong Basin in Cambodia. Stable isotope analysis (based on δ 15 N) was used to estimate TP of common fish species in each river, and species were classified according to occupation of benthic versus pelagic habitats and major feeding guilds. Regression analysis yielded strong correlations between body size and TP among fishes from the Sesan and Sreprok rivers, but not those from the Mekong and Sekong rivers. The Mekong fish assemblage had higher average TP compared with those of other rivers. The relationship between body size and TP was positive and significantly correlated for piscivores and omnivores, but not for detritivores and insectivores. The body size–TP relationship did not differ between pelagic and benthic fishes. Body size significantly predicted TP within the orders Siluriformes and Perciformes, but not for Cypriniformes, the most species-rich and ecologically diverse order in the Lower Mekong River. We conclude that for species-rich, tropical fish assemblages with many detritivores and invertivores, body size would not be an appropriate surrogate for TP in food web models and other ecological applications.

scholarly journals Trophic position and diet shift based on the body size of Coreoperca kawamebari (Temminck & Schlegel, 1843)

2020 ◽  
Vol 44 (1) ◽  
Author(s):  
Jong-Yun Choi ◽  
Seong-Ki Kim ◽  
Jeong-Cheol Kim ◽  
Jung-Do Yoon
Keyword(s):  
Body Size ◽  
Trophic Interactions ◽  
Littoral Zone ◽  
Trophic Position ◽  
Juvenile Fish ◽  
Isotope Analysis ◽  
Central Zone ◽  
The Body ◽  
Diet Shift ◽  
The Relationship

Abstract Background Fish body size is a major determinant of freshwater trophic interactions, yet only a few studies have explored the relationship between the fish body size and trophic interactions in river upstream. In this study, we investigated the relationship between the body size and trophic position (TP) of Coreoperca kawamebari (Temminck & Schlegel, 1843) in an upstream of the Geum River. Results A stable isotope analysis (based on δ15N) was used to determine the TP based on the body size of C. kawamebari. The regression analysis (n = 33, f = 63.840, r2 = 0.68) clearly showed the relationship between the body length and TP of C. kawamebari. The TP of C. kawamebari was clearly divided by body size into the following classes: individuals of size < 10 cm that feed on insects and individuals of size > 10 cm feed on juvenile fish. This selective feeding is an evolutionarily selective tendency to maximize energy intake per unit time. Furthermore, the diet shift of C. kawamebari was led by different spatial distributions. The littoral zone was occupied by individuals of size < 10 cm, and those of size > 10 cm were mainly in the central zone. The littoral zone can be assumed to be enriched with food items such as ephemeropterans and dipterans. Conclusion The TP of C. kawamebari, as a carnivorous predator, will have a strong influence on biotic interactions in the upstream area of the Geum River, which can lead to food web implication.

scholarly journals Body size is negatively correlated with trophic position among cyprinids

2016 ◽  
Vol 3 (5) ◽  
pp. 150652 ◽  
Author(s):  
Edward D. Burress ◽  
Jordan M. Holcomb ◽  
Karine Orlandi Bonato ◽  
Jonathan W. Armbruster
Keyword(s):  
Body Size ◽  
Trophic Position ◽  
Isotope Analysis ◽  
Negative Relationship ◽  
Species Traits ◽  
Food Web Structure ◽  
Mechanical Constraints ◽  
Web Structure ◽  
Significant Negative Relationship ◽  
Multiple Levels

Body size has many ecological and evolutionary implications that extend across multiple levels of organization. Body size is often positively correlated with species traits such as metabolism, prey size and trophic position (TP) due to physiological and mechanical constraints. We used stable isotope analysis to quantify TP among minnows across multiple assemblages that differed in their species composition, diversity and food web structure. Body size significantly predicted TP across different lineages and assemblages, and indicated a significant negative relationship. The observed negative relationship between body size and TP is contrary to conventional knowledge, and is likely to have arisen owing to highly clade-specific patterns, such that clades consist of either large benthic species or small pelagic species. Cyprinids probably subvert the physiological and mechanical constraints that generally produce a positive relationship between body size and TP using anatomical modifications and by consuming small-bodied prey, respectively. The need for herbivorous cyprinids to digest cellulose-rich foods probably selected for larger bodies to accommodate longer intestinal tracts and thereby to facilitate digestion of nutrient-poor resources, such as algae. Therefore, body size and TP are likely to have coevolved in cyprinids in association with specialization along the benthic to pelagic resource axis.

scholarly journals Zooplankton predators and prey: body size and stable isotope to investigate the pelagic food web in a deep lake (Lake Iseo, Northern Italy)

2016 ◽  
Author(s):  
Barbara Leoni
Keyword(s):  
Body Size ◽  
Stable Isotope ◽  
Body Length ◽  
Trophic Position ◽  
Isotope Analysis ◽  
Large Body ◽  
Zooplankton Community ◽  
Open Water ◽  
Northern Italy ◽  
Food Sources

<p>Seasonal changes in trophic position and food sources of deep subalpine lake (Lake Iseo, Northern Italy) zooplankton taxa were investigated during the year 2011. Furthermore, it's combined carbon and nitrogen Stable Isotope Analysis (SIA) with size-specific analyses of both, the major predatory cladoceran (<em>Leptodora kindtii</em><em>,</em> Focke) and two potential preys (<em>Daphnia</em> <em>longispina</em> complex and <em>Eubosmina longicornis</em>). SIA studies have been extremely useful to track the energy flow through complex trophic network, however, if it is applied to analyze relation between two/few species may lead to misleading interpretations. In fact, integrating size-specificity allowed for understanding why <em>L. kindtii</em> nitrogen isotopic fingerprint fully overlapped with <em>Daphnia</em>, in spring. By investigating changes in <em>L. kindtii</em>'s feeding basket, we found that in spring, <em>L. kindtii </em>mainly relied upon <em>E. longicornis </em>as prey, <em>Daphnia</em> being of too large body size for being captured by <em>L. kindtii.</em> Among preys encountered directly in front by a free-swimming <em>Leptodora</em>, only those able to fit into basket opening can be captured. As basket diameter increases with animal body length, size selection of prey depends on <em>L. kindtii</em> body length. As in other deep, subalpine lakes, <em>E. longicornis </em>was less <sup>15</sup>N-enriched than <em>Daphnia</em>, most likely because of exploiting nitrogen fixing, cyanobacteria colonies, commonly detected in Lake Iseo with the onset of thermal stratification. Cyclopoid adults were at the top of zooplankton food chain and they could potentially be feeding on <em>Daphnia</em>. They, however, likely fed in a different habitat (&gt;20 m deep water), as suggested by a rather than negligible carbon fractionation. The results overall suggest that size-specificity is crucial for addressing space and time changes in trophic links between organisms composing the two hierarchical levels within open water zooplankton community.</p><p> </p>

scholarly journals Stable nitrogen isotope analysis of amino acids as a new tool to clarify complex parasite-host interactions within marine food webs

2021 ◽  
Author(s):  
Philip Riekenberg ◽  
Tijs Joling ◽  
Lonneke L. IJsseldijk ◽  
Andreas M. Waser ◽  
Marcel van der Meer ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Stable Isotope ◽  
Food Webs ◽  
Stable Isotope Analysis ◽  
Trophic Interactions ◽  
Trophic Position ◽  
Isotope Analysis ◽  
Isotopic Analysis ◽  
Parasitic Interactions

AbstractTraditional bulk isotopic analysis is a pivotal tool for mapping consumer-resource interactions in food webs but has largely failed to adequately describe parasite-host relationships. Thus, parasite-host interactions remain largely understudied in food web frameworks despite these relationships increasing linkage density, connectance, and ecosystem biomass. Compound-specific stable isotopes from amino acids provides a promising novel approach that may aid in mapping parasitic interactions in food webs. However, to date it has not been applied to parasitic trophic interactions.Here we use a combination of traditional bulk stable isotope analyses and compound-specific isotopic analysis of the nitrogen in amino acids to examine resource use and trophic interactions of five parasites from three hosts from a marine coastal food web (Wadden Sea, European Atlantic). By comparing isotopic compositions of bulk and amino acid nitrogen, we aimed to characterize isotopic fractionation occurring between parasites and their hosts and to clarify the trophic position of the parasites.Our results showed that parasitic trophic interactions were more accurately identified when using compound-specific stable isotope analysis due to removal of underlying source isotopic variation for both parasites and hosts, and avoidance of the averaging of amino acid variability in bulk analyses through use of multiple trophic amino acids. The compound-specific method provided clear trophic discrimination factors in comparison to bulk isotope methods, however, those differences varied significantly among parasite species.Amino acid compound specific isotope analysis has widely been applied to examine trophic position within food webs, but our analyses suggest that the method is particularly useful for clarifying the feeding strategies for parasitic species. Baseline isotopic information provided by source amino acids allows clear identification of the fractionation occurring due to parasite metabolism by integrating underlying isotopic variations from the host tissues. However, like for bulk isotope analysis, the application of a universal trophic discrimination factor to parasite-host relationships remains inappropriate for compound-specific stable isotope analysis. Despite this limitation, compound-specific stable isotope analysis is and will continue to be a valuable tool to increase our understanding of parasitic interactions in marine food webs.

scholarly journals Geographical patterns in the body-size structure of European lake fish assemblages along abiotic and biotic gradients

2014 ◽  
Vol 41 (12) ◽  
pp. 2221-2233 ◽  
Author(s):  
Matthias Emmrich ◽  
Stéphanie Pédron ◽  
Sandra Brucet ◽  
Ian J. Winfield ◽  
Erik Jeppesen ◽  
...  
Keyword(s):  
Body Size ◽  
Fish Assemblages ◽  
Size Structure ◽  
The Body ◽  
Geographical Patterns ◽  
Lake Fish

Regional analysis of body size and population density in stream fish assemblages: testing predictions of the energetic equivalence rule

2002 ◽  
Vol 59 (8) ◽  
pp. 1350-1360 ◽  
Author(s):  
Jason H Knouft
Keyword(s):  
Body Size ◽  
Population Density ◽  
Density Distribution ◽  
Fish Assemblages ◽  
The Body ◽  
Bergmann’S Rule ◽  
Stream Fish ◽  
Bergmann's Rule ◽  
Size Population ◽  
Stream Fish Assemblages

The energetic equivalence rule predicts that body mass (W) and population density (β) within an assemblage are negatively correlated and will exhibit a W–0.75 = β relationship. Bergmann's rule predicts that body size among species will increase with increasing latitude. If species body size increases with latitude, the shape of the body size – population density distribution among assemblages may also vary. This change in the body size – population density distribution, when viewed in the context of the energetic equivalence rule, may indicate an alteration in the use of available energy by individuals of different sizes within an assemblage. Twenty-eight streams were sampled across four geographically distinct regions to determine if stream fish assemblages conform to the prediction of the energetic equivalence rule. Body size in stream fish assemblages did not support the pattern predicted by Bergmann's rule, but rather was negatively correlated with latitude. Stream fish assemblages generally did not conform to the relationship predicted by the energetic equivalence rule. Moreover, these results, coupled with the predictions of the energetic equivalence rule, suggest that larger individuals tended to control a disproportionately greater amount of energy than smaller individuals in stream fish assemblages, which may be partially due to predation pressure on smaller individuals.

scholarly journals Individual variability in stable isotope turnover rates of epidermal mucus according to body size in an omnivorous fish

Hydrobiologia ◽  
2020 ◽  
Vol 848 (2) ◽  
pp. 363-370
Author(s):  
Emily R. Winter ◽  
J. Robert Britton
Keyword(s):  
Body Size ◽  
Stable Isotope ◽  
Isotope Analysis ◽  
Individual Variability ◽  
The Body ◽  
Turnover Rates ◽  
Non Invasive ◽  
Size Groups ◽  
Body Sizes ◽  
Epidermal Mucus

AbstractEpidermal mucus (‘mucus’) is increasingly applied to fish ecological studies based on stable isotope analysis (SIA) due to its non-invasive collection. However, knowledge on mucus SI turnover rates of individual fish remains limited, including uncertainty over how they are influenced by fish body sizes. Here, a diet switch experiment predicted mucus SI turnover rates (δ13C and δ15N) as a function of time using samples taken over 200 days from 10 individually tagged common carp Cyprinus carpio covering two size groups. Non-linear mixed effects models revealed rapid turnover of both δ13C and δ15N (T50: 2–5 days; T95: 9–22 days); δ15N turnover rates were slower for the larger cohort, while δ13C turnover rates were independent of body size. Within size groups, turnover rates were not expected to vary between individuals. These experimental results suggest that due to these fast turnover rates, epidermal mucus can provide insights into the diets of fish over very short timeframes, although for δ15N the body size of the fish needs consideration.

scholarly journals Improvements of Population Fitness and Trophic Status of a Benthic Predatory Fish Following a Trawling Ban

2021 ◽  
Vol 8 ◽  
Author(s):  
Lily S. R. Tao ◽  
Yanny K. Y. Mak ◽  
Valerie C. M. Ho ◽  
Ronia C.-t. Sham ◽  
Tommy T. Y. Hui ◽  
...  
Keyword(s):  
Hong Kong ◽  
Body Size ◽  
Size Structure ◽  
Trophic Position ◽  
Isotope Analysis ◽  
Trophic Niche ◽  
Trophic Dynamics ◽  
Predatory Fish ◽  
Benthic Habitats ◽  
Fish Samples

Trawl fisheries have been shown to cause overfishing and destruction of benthic habitats in the seabed. To mitigate these impacts, a trawling ban has been enforced in Hong Kong waters since December 31, 2012 to rehabilitate the ecosystem and enhance fisheries resources. Previous studies demonstrated that reduced trawling activities would increase the heterogeneity of benthic habitats, thereby enhancing species richness and abundance of benthic fauna and providing more prey resources for predatory fishes. This study aimed to test a hypothesis that the population and trophic dynamics of the Bartail flathead Platycephalus indicus, a heavily fished benthic predatory fish, at inner and outer Tolo Channel of Hong Kong (i.e., EI and EO) improved with increases in their body size, abundance, biomass, trophic niche, and trophic position after the trawl ban. Samples were collected from trawl surveys before and after the trawl ban to compare the pre-ban and post-ban populations of P. indicus from EI and EO. Body size, abundance, and biomass were assessed in 2004, 2013–2014, and 2015–2016, whereas trophic niche and trophic position were analyzed based on stable isotopes of fish samples collected in dry season of 2012, 2015, and 2018. Following the trawl ban, the abundance and biomass of P. indicus increased in EO, with body size increased in EI. Furthermore, as indicated by the results of stable isotope analysis (SIA) on their tissues and prey items, trophic niche, and trophic position of P. indicus increased in EI and EO, respectively. Our study demonstrated that the trawl ban had promoted the recovery of a predatory fish population through restoring size structure and trophic dynamics.

Trophic position scales positively with body size within but not among four species of rocky reef predators

2020 ◽  
Vol 640 ◽  
pp. 189-200 ◽  
Author(s):  
AM Olson ◽  
A Frid ◽  
JBQ dos Santos ◽  
F Juanes
Keyword(s):  
Body Size ◽  
Trophic Position ◽  
Stomach Contents ◽  
Rocky Reef ◽  
Morphometric Traits ◽  
Predator Species ◽  
Predatory Fishes ◽  
Average Size ◽  
Interspecific Comparisons ◽  
Large Predators

Intra- and interspecifically, larger-bodied predators generally occupy higher trophic positions (TPs). With widespread declines in large predators, there is a need to understand their size-based trophic roles to predict ecosystem-level responses. In British Columbia, Canada, we examined size-based trophic interactions between predatory fishes—3 rockfish species (genus Sebastes) and lingcod Ophiodon elongatus—and their prey, converting predator δ15N signatures to TP and analyzing stomach contents. Intraspecifically, TP scaled positively with predator length and gape width, but the rates of change varied by species. Interspecifically, TP did not scale positively with the observed mean sizes or known maximum sizes of species. Lingcod TP was lower than that of yelloweye and quillback rockfishes, which were 51 and 37%, respectively, smaller than lingcod. Yellowtail rockfish had the smallest average size, yet their mean TP did not differ significantly from that of lingcod. Neither species differences in some morphometric traits known to influence body size-TP relationships nor phylogenetic history explained these results. Most prey consumed were <20% of the predator’s size, which might partially explain the lack of a size-based trophic hierarchy among species. Currently, large size classes of rockfishes are being lost due to fisheries and perhaps climate-driven changes. Our findings on intraspecific size-TP relationships indicate that fishery removals of large individuals may diminish trophic structures. Interspecific comparisons of TP suggest that, along with size, species remain an important factor in understanding trophic dynamics. In addition, smaller-bodied predator species may have significant ecological roles to be considered in ecosystem-based fisheries management.

The Body Size of Headstarted and Wild Juvenile European Pond Turtles (Emys orbicularis)

2017 ◽  
Vol 25 (2) ◽  
pp. 161
Author(s):  
Sławomir Mitrus ◽  
Bartłomiej Najbar ◽  
Adam Kotowicz ◽  
Anna Najbar
Keyword(s):  
Body Size ◽  
The Body ◽  
Emys Orbicularis
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