scholarly journals Trophic plasticity of the highly invasive topmouth gudgeon (Pseudorasbora parva) inferred from stable isotope analysis

2019 ◽  
Author(s):  
Matteo Rolla ◽  
Sofia Consuegra ◽  
Carlos Garcia de Leaniz

AbstractA wide trophic niche and high trophic plasticity are often invoked to explain the successful establishment of many aquatic invaders, but there is little information regarding the diet of most invasive fish in European waters. We combined stomach content and stable isotope analysis (SIA) of13C and15N to examine the trophic niche of the highly invasive topmouth gudgeon (Pseudorasbora parva) in four contrasting ponds and reservoirs in South Wales. Marked differences in diet and trophic position were found among neighbouring systems only a few kilometres apart. The most diverse diet was found in ponds with the fewest number of inter-specific competitors, and resulted in topmouth gudgeon having the highest condition factor, the widest variation in δ13C and δ15N values, and the highest carbon content, typical of generalist feeders. In contrast, topmouth gudgeon that coexisted with other cyprinids, were much more likely to have empty stomachs and relied almost exclusively on plant seeds, resulting in fish having a poor condition factor and low trophic position. Comparisons with other trophic studies indicate that variation in isotope values among neighbouring sites can exceed variation across continents, making it difficult to predict the diet or trophic impacts of the invasive topmouth gudgeon. Given the importance of obtaining reliable data on trophic position for risk assessment, our study shows that the use of SIA could be used to prioritize control and eradication measures that take into account trophic plasticity.

2016 ◽  
Vol 18 (12) ◽  
pp. 3611-3621 ◽  
Author(s):  
Paride Balzani ◽  
Salvatrice Vizzini ◽  
Giacomo Santini ◽  
Alberto Masoni ◽  
Claudio Ciofi ◽  
...  

2021 ◽  
Vol 8 ◽  
Author(s):  
Fanyu Zhou ◽  
Junya Hirai ◽  
Koji Hamasaki ◽  
Sachiko Horii ◽  
Atsushi Tsuda

Euphausiids are abundant micronekton and important links between higher and lower trophic levels in marine ecosystems; however, their detailed diets cannot be fully understood by conventional microscopy, especially in subtropical areas. Here, we report the euphausiid community structure in the California Current (CC) area and the eastern/western North Pacific subtropical gyre (ESG and WSG) and detail the feeding ecology of the dominant species (Euphausia pacifica, E. brevis, and E. hemigibba) in each region using a combined approach of gut content analysis via 18S V9 metabarcoding and stable carbon and nitrogen isotope analysis. A pronounced omnivorous feeding of all studied euphausiid species was supported by both methods: phytoplanktonic taxonomic groups (Dinophyta, Stramenopiles, and Archaeplastida), Copepoda, and Hydrozoa were detected in the gut contents; all the three euphausiid species displayed an intermediate trophic position between the net plankton (0.2–1.0 mm) and the myctophid fish (15.2–85.5 mm). However, Hydrozoa found in euphausiid gut contents likely derived from a potential cod-end feeding, based on isotope analysis. E. pacifica in the CC province ingested more autotrophic prey, including pelagophyte and green algae, due to a greater abundance of Stramenopiles and Archaeplastida in shallow layers of CC water. On the other hand, non-autotrophic prey such as mixotrophic Kareniaceae dinoflagellates, Pontellidae and Clausocalanidae copepods, and Sphaerozoidae rhizarian contributed more to the diets of E. brevis and E. hemigibba because of a lower chlorophyll a concentration or potentially a scarcity of autotrophic prey availability in ESG and WSG. The feeding patterns of dominant euphausiid species conducting filter feeding were thus largely determined by phytoplankton prey availability in the environments. Dietary difference across three species was also indicated by stable isotope analysis, with a lower mean trophic level of E. pacifica (2.32) than E. brevis (2.48) and E. hemigibba (2.57). These results verify direct trophic interactions between euphausiids and primary production and suggest that the omnivorous feeding habit is a favorable character for dominant Euphausia species.


The Condor ◽  
2004 ◽  
Vol 106 (3) ◽  
pp. 638-651 ◽  
Author(s):  
Cynthia A. Paszkowski ◽  
Beverly A. Gingras ◽  
Kayedon Wilcox ◽  
Paul H. Klatt ◽  
William M. Tonn

Abstract We compared trophic ecology of grebes inferred from stable-isotope analysis to that from gut contents, and compared isotopic ratios of Red-necked Grebes (Podiceps grisegena) from lakes differing in their food webs. Analyses of different grebe tissues (egg yolk and albumen, pectoral and leg muscle, breast and primary feathers) also allowed us to assess the effectiveness of these tissues at representing grebe trophic relations. Isotopic ratios from pectoral and leg muscles were similar, based on comparisons within individual birds. Enriched values of δ15N and δ13C suggested that breast and primary feathers were molted over winter, and therefore reflected a marine food web. Albumen and yolk of grebe eggs and muscle tissues from downy chicks, however, matched isotopic characteristics of the local food web, indicating that female Red-necked Grebes use nutrients from the breeding lake for egg formation. Eggs, therefore, can provide excellent material for isotopic analysis aimed at assessing trophic relations of Red-necked Grebes on breeding lakes. Gut contents and stable isotopes both indicated that grebes from lakes with fish consumed a mixed diet of fish and macroinvertebrates and occupied the highest trophic level, at or above the level of piscivorous fishes. In contrast, grebes from lakes lacking fish occupied a lower trophic position. Relaciones Tróficas de Podiceps grisegena en Lagos del Bosque Boreal del Oeste: Un Análisis de Isótopos Estables Resumen. Comparamos la ecología trófica de Podiceps inferida a partir de análisis de isótopos estables con la de contenidos estomacales y comparamos las relaciones isotópicas de P. grisegena entre lagos que difieren en sus redes tróficas. Los análisis de diferentes tejidos de P. grisegena (yema y albumen del huevo, músculo pectoral y de la pierna, plumas del pecho y primarias) también nos permitieron evaluar la efectividad de estos tejidos para representar las relaciones tróficas de P. grisegena. Las relaciones isotópicas de los músculos pectorales y de las piernas basadas en comparaciones realizadas para cada ave individual fueron similares. Valores enriquecidos de δ15N y δ13C sugirieron que las aves mudaron las plumas del pecho y las primarias durante el invierno, y por lo tanto reflejaron una red trófica marina. El albumen y la yema del huevo de P. grisegena y los tejidos musculares de pichones emplumados, sin embargo, coincidieron con las características isotópicas de la red alimenticia local, indicando que las hembras de P. grisegena usan nutrientes del lago donde nidifican para la formación de los huevos. Los huevos, por lo tanto, pueden constituir un material excelente para análisis isotópicos centrados en evaluar las relaciones tróficas de P. grisegena en los lagos donde se reproducen. Los contenidos estomacales y los isótopos estables indicaron que los individuos de P. grisegena provenientes de lagos con peces consumieron una dieta mixta de peces y macroinvertebrados y ocuparon la posición trófica más alta, al mismo nivel o por arriba de los peces piscívoros. En contraste, los individuos provenientes de lagos sin peces ocuparon una posición trófica menor.


Author(s):  
Wei-Chuan Chiang ◽  
Ching-Tsun Chang ◽  
Daniel J. Madigan ◽  
Aaron B. Carlisle ◽  
Michael K. Musyl ◽  
...  

2020 ◽  
Vol 637 ◽  
pp. 181-194 ◽  
Author(s):  
JS Curtis ◽  
MA Albins ◽  
EB Peebles ◽  
CD Stallings

Patterns of stable isotopes recorded in metabolically stable, serially synthesized, structures such as eye lenses can yield robust descriptions of resource use across the life histories of individual fish. We performed stable isotope analysis of eye lenses sampled from invasive lionfishes Pterois spp. and a potentially competitive native mesopredator, the graysby Cephalopholis cruentata, to compare lifelong patterns of trophic resource use on a coral reef ledge in Biscayne National Park, Florida, USA. In both lionfishes and graysby, stable isotope values increased logarithmically with eye-lens radius, likely reflecting increases in trophic position with growth. Tissue samples toward the interior of the lens were the most isotopically similar between lionfish and graysby, suggesting interspecific resource use overlap may be strongest in smaller fish. We observed substantial variation in isotopic chronologies around the underlying logarithmic trend within individual fish, potentially driven by patterns of movement across measured environmental isotopic gradients, intraspecific variation in resource use specificity, or other ecological variables of interest. These results are the first to describe patterns of size-structured resource use across the life of individual lionfish, an important objective for researchers studying the interactions of this highly invasive species with the surrounding ecological communities. Additionally, through this example, we illustrate analytical approaches and considerations for the application of eye-lens stable isotope analysis to the study of vertebrate ecology.


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