Food sources of common dolphinfish (Coryphaena hippurus) based on stomach content and stable isotopes analyses

2014 ◽  
Vol 95 (3) ◽  
pp. 579-591 ◽  
Author(s):  
A. Tripp-Valdez ◽  
F. Galván-Magaña ◽  
S. Ortega-García
Keyword(s):  
Stable Isotope ◽  
Stomach Content ◽  
Gulf Of California ◽  
Stomach Contents ◽  
Isotopic Analysis ◽  
Stomach Content Analysis ◽  
Food Sources ◽  
Important Prey ◽  
Opportunistic Predator ◽  
Ecological Importance

Dolphinfish (Mahimahi) are a high-demand resource for sport and coastal fisheries, mainly in the Pacific Ocean. Due to their economic and ecological importance, studies of their biology are very important to understand their function in ecosystems. We used stable isotope and stomach content analyses to determine the most important prey of the common dolphinfish, as well as the trophic level of this species in two areas of the southern Gulf of California. Stomach contents of 445 specimens were analysed. Using both techniques, we found that the most important prey for dolphinfish in the southern Gulf of California were three invertebrate species followed by fish. This contrasts with results from other authors who found that this species was mainly piscivorous in other locations. Stomach content analysis indicated differences in prey biomass by area, season and size class. The isotopic analysis did not show significant differences between seasons or sexes. Both stomach contents and stable isotope analyses showed that although this predator consumed a wide prey spectrum, only a few prey items made up the bulk of the diet, which resulted in a low SD in δ15N values and low Levin's index values. We conclude that this fish is an opportunistic predator that may consume a wide prey spectrum, but that it mainly consumes prey that are abundant in the area, such as crustaceans and cephalopods in the Gulf of California.

Sources of variability and comparability between salmonid stomach contents and isotopic analyses: study design lessons and recommendations

2011 ◽  
Vol 68 (1) ◽  
pp. 137-151 ◽  
Author(s):  
Mark R. Vinson ◽  
Phaedra Budy
Keyword(s):  
Stable Isotope ◽  
Study Design ◽  
Stomach Content ◽  
Stomach Contents ◽  
Stomach Content Analysis ◽  
Diet Overlap ◽  
Target Species ◽  
Relative Information ◽  
Isotopic Analyses ◽  
Diet Analyses

We compared sources of variability and cost in paired stomach content and stable isotope samples from three salmonid species collected in September 2001–2005 and describe the relative information provided by each method in terms of measuring diet overlap and food web study design. Based on diet analyses, diet overlap among brown trout, rainbow trout, and mountain whitefish was high, and we observed little variation in diets among years. In contrast, for sample sizes n ≥ 25, 95% confidence interval (CI) around mean δ15Ν and δ13C for the three target species did not overlap, and species, year, and fish size effects were significantly different, implying that these species likely consumed similar prey but in different proportions. Stable isotope processing costs were US$12 per sample, while stomach content analysis costs averaged US$25.49 ± $2.91 (95% CI) and ranged from US$1.50 for an empty stomach to US$291.50 for a sample with 2330 items. Precision in both δ15Ν and δ13C and mean diet overlap values based on stomach contents increased considerably up to a sample size of n = 10 and plateaued around n = 25, with little further increase in precision.

scholarly journals Diet of Leptobotia elongata revealed by stomach content analysis and inferred from stable isotope signatures

2015 ◽  
Vol 98 (8) ◽  
pp. 1965-1978 ◽  
Author(s):  
L. Li ◽  
Q. Wei Wei ◽  
J. Ming Wu ◽  
H. Zhang ◽  
Y. Liu ◽  
...  
Keyword(s):  
Content Analysis ◽  
Stable Isotope ◽  
Stomach Content ◽  
Stomach Content Analysis ◽  
Stable Isotope Signatures

Feeding behaviour of greater amberjackSeriola dumerili(Risso, 1810) from Central Mediterranean (Gulf of Gabes, Tunisia)

2016 ◽  
Vol 96 (6) ◽  
pp. 1229-1234 ◽  
Author(s):  
Ayda Sley ◽  
Aymen Hadj Taieb ◽  
Othman Jarboui ◽  
Mohamed Ghorbel ◽  
Abderrahmen Bouain
Keyword(s):  
Stomach Contents ◽  
Frequency Of Occurrence ◽  
Central Mediterranean ◽  
Gulf Of Gabes ◽  
Seriola Dumerili ◽  
Gulf Of Gabès ◽  
Important Prey ◽  
Significant Difference ◽  
Opportunistic Predator ◽  
Greater Amberjack

The diet of greater amberjackSeriola dumerili(Carangidae) in the Gulf of Gabes (Tunisia, Mediterranean) was described from analysis of stomach contents of 290 specimens fished between June 2004 and May 2006. The index of vacuity (%VI) was relatively low (37.9%) and differed significantly across size classes.Seriola dumeriliis an opportunistic predator that consumes mostly pelagic organisms; benthic prey were also examined in small proportion. The diet was quantified using the frequency of occurrence (%O), numerical abundance (%N), weight (%W) and the index of relative importance (IRI and %IRI) for each prey taxa. The most important prey were teleosts (%IRI = 99.61); molluscs and crustaceans were found occasionally (%IRI, 0.38 and 0.01%, respectively). Among teleosts, Clupeidae were also the dominant food items in number (%N = 36.06%) and then in frequency of occurrence (%O = 36.7%). In term of weight, Sparidae were the most abundant prey (%W = 36.5%). There is no significant difference between male and female diets. Seasonal differences in the diet components were observed.

Fish on the roof of the world: densities, habitats and trophic position of stone loaches (Triplophysa) in Tibetan streams

2017 ◽  
Vol 68 (1) ◽  
pp. 53 ◽  
Author(s):  
Dean Jacobsen ◽  
Søren Kock Laursen ◽  
Ladislav Hamerlik ◽  
Karen Moltesen ◽  
Anders Michelsen ◽  
...  
Keyword(s):  
Trophic Position ◽  
Stomach Contents ◽  
Benthic Algae ◽  
Stomach Content Analysis ◽  
Food Sources ◽  
Fish Length ◽  
The Tibetan Plateau ◽  
Running Waters ◽  
Ecological Data ◽  
Percentage Cover

The fast increase in temperature on the Tibetan Plateau, with anticipated future changes in aquatic ecosystems and biodiversity, highlights the urgent need for ecological data on the sparsely studied Tibetan running waters. In the present study we surveyed eight Tibetan streams to obtain data on densities, feeding selectivity and trophic position of the stone loach Triplophysa. Benthic algae, detritus, macroinvertebrates and fish were quantified and collected for stable isotope and stomach content analysis. Triplophysa density (mean 0.70 individuals m–2, maximum 1.6 individuals m–2) decreased with altitude and increased with the percentage cover of fine substratum. Glacier-fed sites tended to have the lowest fish densities, whereas the highest densities were found near lakes. Mean fish length (4.1–9.6cm) was positively related to the percentage cover of coarse substratum. Triplophysa was omnivorous, but the composition of the stomach contents varied greatly between sites and among individuals. Algal matter was ingested at most sites, but macroinvertebrates (Chironomidae, Baetidae and Simuliidae) dominated the ingestion (average 50–100%). The trophic position of Triplophysa, identified from δ15N (‰) of the biota, varied between 2.6 and 4.2 among localities (mean 3.6) and was inversely related to the biomass of benthic algae, but unrelated to quantities of other potential food sources.

scholarly journals Dietary composition of birds species at an inland airport in South Africa

2002 ◽  
Vol 21 (1) ◽  
pp. 16-18
Author(s):  
A. C. Kok ◽  
O. B. Kok
Keyword(s):  
Bird Species ◽  
Stomach Contents ◽  
Total Sample ◽  
Dry Mass ◽  
Food Sources ◽  
Mass Composition ◽  
Potential Threat ◽  
Important Prey ◽  
Lesser Kestrel ◽  
Main Food Source

Stomach contents of 51 bird species that posed a potential threat to aviation were collected at the Bloemfontein airport over a period of 11 years (1985-1995). Numerically the crowned plover (Vanellus coronatus), and the lesser kestrel (Falco naumanni), blacksmith plover (V. armatus), whitewinged korhaan (Eupodotis afraoides), doublebanded courser (Smutsornis africanus), spotted dikkop (Burhinus capensis), cattle egret (Bubulcus ibis), Swainson’s francolin (Francolinus swainsonii) and Orange River francolin (F. levaillantoides) in sequence of importance, constituted 91,0% of the total sample (3 544). In general insects can be considered the main food source of the birds concerned. Based on dry mass composition the Isoptera, followed by the Coleoptera and Orthoptera, constituted the most important component in the diet. The Isoptera, more specifically the harvester termite (Hodotermes mossambicus), is, moreover, the only important prey taxon showing a conspicuous utilisation peak during the relative food shortage of the dry season. Evidently, temporary superabundant food sources that periodically come about in grassland habitats are opportunistically utilised by the birds.

Feeding habits and trophic level of the shovelnose guitarfish (Pseudobatos productus) in the upper Gulf of California

2017 ◽  
Vol 98 (7) ◽  
pp. 1783-1792 ◽  
Author(s):  
Fausto Valenzuela-Quiñonez ◽  
Felipe Galván-Magaña ◽  
David A. Ebert ◽  
E. Alberto Aragón-Noriega
Keyword(s):  
Stable Isotope ◽  
Stomach Content ◽  
Gulf Of California ◽  
Feeding Habits ◽  
Isotope Analysis ◽  
Trophic Relationships ◽  
Generalist Predators ◽  
Class Iii ◽  
Ontogenetic Changes ◽  
Diet Shifts

The shovelnose guitarfish (Pseudobatos productus) is the most abundant and economically important batoid in Gulf of California fisheries. Despite the importance of the guitarfish in the demersal ecosystem, its trophic relationships are poorly understood. Results from stomach content and stable isotope analysis indicate P. productus is a specialist predator that feeds on coastal benthic organisms, mainly crustaceans, followed by fishes and cephalopods in the Upper Gulf of California. Males and females did not differ in dietary composition and isotopic values. Pseudobatos productus displayed ontogenetic changes in the diet, with smaller, immature individuals having a more specialized diet and mature individuals becoming generalist predators. Size classes I (<570 mm) and II (>570 mm) fed almost exclusively on crustaceans (99.78% and 82.37 %IRI, respectively). Size class III (>832 mm) increased consumption of fishes (22.11 %IRI) and squid (6.54 %IRI). Ontogenetic diet shifts were strongly supported by the SIAR mixing model. Stomach content and stable isotope analyses classify P. productus as a second-order predator.

Niche differentiation of bottlenose dolphin species in South Australia revealed by stable isotopes and stomach contents

2011 ◽  
Vol 38 (4) ◽  
pp. 261 ◽  
Author(s):  
Susan E. Gibbs ◽  
Robert G. Harcourt ◽  
Catherine M. Kemper
Keyword(s):  
Stable Isotope ◽  
Stomach Content ◽  
Bottlenose Dolphin ◽  
South Australia ◽  
Stomach Contents ◽  
Primary Source ◽  
Niche Differentiation ◽  
Numerical Abundance ◽  
Significant Difference ◽  
Management And Conservation

Context Animal species with overlapping ranges are common worldwide, but how these species coexist is less obvious. Dolphins are protected in Australia and yet little information is available on their resource use which is essential for successful management and conservation. Aim The aim of this study was to determine the degree of overlap in diet and feeding ecology of the two Tursiops spp. that have overlapping ranges in South Australia. Methods Stomach content (91 Tursiops sp. and 14 T. truncatus) and stable isotope (δ13C, δ15N) analyses (39 Tursiops sp. and 14 T. truncatus) were conducted. Carcasses of dolphins were opportunistically collected between 1974 and 2005. Diet was quantified by frequency of occurrence (FOO) and numerical abundance (NA) of prey. Key results Delta13C from teeth revealed distinct differences in primary source of carbon, corresponding to coastal (Tursiops sp. n = 39,  = –12.24, s.d. = 1.32) and offshore habitats (T. truncatus n = 14,  = –14.21, s.d. = 0.55). Differences in δ15N revealed Tursiops sp. ( = 11.66, s.d. = 0.58) feeds at a lower trophic level than T. truncatus ( = 14.29, s.d. = 0.88). Stomach content analyses for Tursiops sp. corroborated stable isotope results. There was a significant difference between the diets of Tursiops sp. from north Spencer Gulf and south Spencer Gulf (ANOSIM R = 0.249, P = 0.001). Prey were generally demersal in habit with the most important from the cephalopod families Octopodidae, Sepiidae and Loliginidae and fish families Carangidae, Clupeidae, Terapontidae and Apogonidae. For T. truncatus there were insufficient stomach contents for assessment. Conclusions South Australian bottlenose dolphin species exhibit distinct niche differentiation with clear evidence of regional variation in the diet of Tursiops sp. Implications The between and within species diet differentiation demonstrated, highlights the importance of regional management. Such results are internationally significant as coastal and offshore forms of Tursiops spp. occur worldwide.

Effect of prey abundance and size on the distribution of demersal fishes

2012 ◽  
Vol 69 (1) ◽  
pp. 191-200 ◽  
Author(s):  
Andrew F. Johnson ◽  
Maria Valls ◽  
Joan Moranta ◽  
Stuart R. Jenkins ◽  
Jan G. Hiddink ◽  
...  
Keyword(s):  
Fish Species ◽  
Stomach Content ◽  
Prey Size ◽  
Prey Availability ◽  
Demersal Fish ◽  
Stomach Content Analysis ◽  
Prey Abundance ◽  
Food Sources ◽  
Gape Size ◽  
Feeding Potential

Many demersal fish species rely on benthic prey as food sources for part of, or in some cases, all of their life history. We investigated the relationships between prey and predator abundance and prey size and predator mouth gape size for nine demersal fish species. Of the species analysed, four showed a significant positive increase in abundance with increasing prey abundance. Prey size is thought to be an important parameter for demersal fish that are limited in their feeding potential by their mouth gape size, as it influences consumption rate and energy expenditure while foraging. The relationship between prey size and mouth gape was investigated using both stomach content data and prey availability data. Stomach content analysis revealed positive relationships between maximum prey size and predator mouth gape size for six of the species. Indications of prey size selectivity were only seen in the environment for European hake ( Merluccius merluccius ), highlighting the potential importance of prey size over prey abundance for this species. The results demonstrate that prey abundance and size are of significance for some demersal fish species feeding primarily on benthos and will help in defining habitat requirements of demersal fish species.

scholarly journals Seasonal Dynamics of Stomach Contents, Trophic Level, Length-Weight Relationship and Condition Factor of Mystus bleekeri (Day, 1877)

2021 ◽  
Vol 50 (4) ◽  
pp. 907-918
Author(s):  
Sabuj Kanti Mazumder ◽  
Mrityunjoy Kunda ◽  
Mohammed Mahbub Iqbal ◽  
Lipi Rani Basak ◽  
Simon Kumar Das
Keyword(s):  
Trophic Level ◽  
Stomach Content ◽  
Condition Factor ◽  
Stomach Contents ◽  
Stomach Content Analysis ◽  
K Value ◽  
Weight Relationship ◽  
Food Fish ◽  
The Mean ◽  
Asian Catfish

The Asian catfish Mystus bleekeri is a popular food fish along with favored as an ornamental fish in Bangladesh. Till now detailed report on stomach contents, trophic level, length-weight relationship and condition factor of this fish species in the agro-climatic context of Bangladesh is lacking. Hence, the aims of this study were to describe the stomach content, trophic level, length-weight relationship (LWR) and condition factors of Mystus bleekeri collected from Dekhar Haor, Sylhet, Bangladesh from July 2017 to June 2018. A total of 600 specimens ranging from 6.9-24.6 cm total length (TL) and 5.7-72.4 g body weight (BW) was analyzed in this study. Stomach content analysis showed that the fish fed mostly on Mollusca with a frequency of occurrence (fo: 25.36%) and worms (fo: 21.68%), followed by plant matters (fo: 3.32%), Cladocerana (fo: 1.18%), Copepoda (fo: 0.95%), and Teleostei (fo: 0.36%). The estimated mean trophic level (TROPH) ranged from 2.35±0.13 in December to 3.02±0.23 in August, indicating that they are opportunistic feeder. The LWR analysis showed negative allometric growth (b<3) throughout the year. The values of the exponent b in the LWR (W=aLb) vary between 1.474 and 2.490.The mean K value was significantly higher in October indicating the heavier weight and better condition of the fish (P<0.05). The data obtained from this study would be useful to introduce sustainable management of Mystus bleekeri not only in Dekhar Haor but also in other inland waters of Bangladesh.

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