scholarly journals Temporal variations in the feeding habits and trophic levels of three deep-sea demersal fishes from the western Mediterranean Sea, based on stomach contents and stable isotope analyses

2010 ◽  
Vol 402 ◽  
pp. 213-232 ◽  
Author(s):  
E Fanelli ◽  
JE Cartes
Keyword(s):  
Stable Isotope ◽  
Mediterranean Sea ◽  
Deep Sea ◽  
Feeding Habits ◽  
Stomach Contents ◽  
Temporal Variations ◽  
Western Mediterranean ◽  
Trophic Levels ◽  
Western Mediterranean Sea ◽  
Isotope Analyses

Feeding habits of the short-finned squidIllex coindetiiin the western Mediterranean Sea using combined stomach content and isotopic analysis

2015 ◽  
Vol 96 (6) ◽  
pp. 1235-1242 ◽  
Author(s):  
Francisco Martínez-Baena ◽  
Joan Navarro ◽  
Marta Albo-Puigserver ◽  
Isabel Palomera ◽  
Rigoberto Rosas-Luis
Keyword(s):  
Mediterranean Sea ◽  
Stomach Content ◽  
Feeding Habits ◽  
Western Mediterranean ◽  
Trophic Levels ◽  
Mesopelagic Fish ◽  
Western Mediterranean Sea ◽  
Isotopic Analyses ◽  
Stable Isotopic ◽  
Prey Items

The ommastrephid squid,Illex coindetii, is one of the most abundant cephalopods in the Mediterranean Sea and an important predator in the ecosystem. In the present study, we examined the diet habits ofI. coindetiiin the north-western Mediterranean Sea by combining two complementary approaches: stomach content and stable isotopic analyses. Specifically, we examined whether the diet differed between sizes and seasons. Stomach content results indicated that the diet ofI. coindetiiwas composed of 35 prey items including four major groups; namely the crustaceansPasiphaea sivado, Amphipods, squid of the Order Teuthida, and pelagic and mesopelagic fish. Differences were found among different ontogenetic sizes: juvenile individuals fed mainly on crustaceans (%IRI = 77.59), whereas adult individuals fed on a wider range of prey items, including the shrimpP. sivado(%IRI = 33.21), the amphipodAnchylomera blossevillei(%IRI = 0.91), the decapodPlesionikasp. (%IRI = 0.19), the carangidTrachurus trachurus(%IRI = 0.34) and some Myctophids species (%IRI = 0.21). Differences were also found between seasons in the year. In winter, crustaceans were the main prey items, whereas in summer the diversity of prey was higher, including fish, crustaceans and molluscs. Similar to the stomach contents, stable isotopic results indicated differences among sizes. δ15N values were higher in adult squids than in juveniles because they fed on prey at higher trophic levels. In conclusion, this study indicates that feeding habits ofI. coindetiivary seasonally and ontogenetically. These feeding variations may be associated with trophic competence scenarios based on size, and also with the availability and abundance of prey throughout the year.

Feeding ecology of striped dolphins, Stenella coeruleoalba, in the north-western Mediterranean Sea based on stable isotope analyses

2011 ◽  
Vol 92 (8) ◽  
pp. 1677-1687 ◽  
Author(s):  
A.M. Meissner ◽  
C.D. MacLeod ◽  
P. Richard ◽  
V. Ridoux ◽  
G. Pierce
Keyword(s):  
Stable Isotope ◽  
Mediterranean Sea ◽  
Trophic Level ◽  
Western Mediterranean ◽  
Stenella Coeruleoalba ◽  
The North ◽  
Western Mediterranean Sea ◽  
The Mediterranean ◽  
Isotope Analyses ◽  
North Western

The feeding ecology of striped dolphin, Stenella coeruleoalba, in the north-western Mediterranean Sea was studied using stable isotope analyses. Carbon and nitrogen stable isotope ratios were measured in skin and muscle tissues of stranded and by-caught dolphins from six geographical areas in the Mediterranean Sea and Atlantic Ocean. Variation in δ15N in relation to dolphin size is attributed to changes in diet. Nursing calves have a higher trophic level than weaned animals and their δ15N values decrease progressively until weaning, estimated to be at a body length of around 155 cm. δ15N values then increased for larger individuals which suggests changes in diet for mature dolphins. Geographical differences in diet were apparent between the Atlantic and the Mediterranean, although no clear differences were apparent between the five Mediterranean areas. Comparisons of the nitrogen isotope ratios of skin and muscle highlighted a higher fractionation in skin compared to the muscle tissue. Values of δ13C also increased with body length although it appears that this is not only driven by trophic level enrichment. δ13C increases before weaning and the difference in trophic level between newly-weaned and mature dolphins was twice as high for carbon as for nitrogen. Ontogenetic changes in carbon isotope composition may therefore be driven by feeding on deep water prey and dolphin movements outside the coastal feeding grounds. Indeed, seasonal variations in δ13C are suspected to be driven by migration within the Mediterranean basin.

Feeding Habits of Alepocephalus Rostratus (Pisces: Alepocephalidae) in the Western Mediterranean Sea

1998 ◽  
Vol 78 (4) ◽  
pp. 1295-1306 ◽  
Author(s):  
M. Carrassón ◽  
J. Matallanas
Keyword(s):  
Mediterranean Sea ◽  
Prey Item ◽  
Narrow Range ◽  
Feeding Habits ◽  
Western Mediterranean ◽  
Western Mediterranean Sea ◽  
The Family ◽  
Different Seasons ◽  
Scarcity Of Resources ◽  
Important Fish

The present study examines the feeding habits of Alepocephalus rostratus, the only species of the family Alepocephalidae in the Mediterranean Sea and the second most important fish species, in terms of biomass, inhabiting the deep slope of the Catalan Sea. Samples were obtained at depths between 1000–2250 m. Diet was analysed for two different size-classes (immature and mature specimens) at three different bathymetric strata during two different seasons. The feeding habits of A. rostratus included a narrow range of mobile macroplanktonic organisms (e.g. Pyrosoma atlanticum and Chelophyes appendiculata) and some material of benthic origin. Pyrosoma atlanticum was the preferred prey item in spring at 1000–1425 m, being very scarce in summer at the same depth as a consequence of its scarcity in the environment during this season. There were some ontogenic differences in the diet of A. rostratus at 1425–2250 m. Adults ingested more and larger prey than juvenile specimens. The scarcity of resources below 1200–1400 m fostered a more diversified diet, as well as passive predation of sedimented material.

scholarly journals A little can be enough. Native fish from the Western Mediterranean Sea can act as a control agent for the invasive alga Caulerpa cylindracea

2018 ◽  
Author(s):  
Jorge Santamaría ◽  
Fiona Tomas ◽  
Enric Ballesteros ◽  
Juan Manuel Ruiz ◽  
Jorge Terrados ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Fish Species ◽  
Biotic Resistance ◽  
Stomach Contents ◽  
Control Agent ◽  
Western Mediterranean ◽  
Exclusion Experiment ◽  
Invasive Algae ◽  
Western Mediterranean Sea ◽  
Invasive Alga

In the Mediterranean Sea, different organisms can feed on invasive algae species, yet, how these species provide biotic resistance against algal invasions remains unclear. In this study, we analyzed fish stomach contents to determine which fish species feed on Caulerpa cylindracea and we performed an exclusion experiment to experimentally test how this grazing activity may limit invasive algae abundance and spread. Our results show that several fish species, many of them not considered strictly herbivores, feed on the invasive alga; however, the Ivlev´s Index suggests that its consumption was accidental except for Sarpa salpa. Additionally, the exclusion experiment demonstrated that fish species can limit C. cylindracea coverage at 10m but not at 30m deep; which is likely linked to the higher abundance and activity of these fish species at depths above 25m. These results are in agreement with the current distribution of C. cylindracea, which is much more abundant at depths from 25 to 50m. In this study we show that fish herbivory is a form of biotic resistance against C. cylindracea at shallow depths, not being able to completely remove it, but controlling its abundance.

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