scholarly journals Stable isotopes, beaks and predators: a new tool to study the trophic ecology of cephalopods, including giant and colossal squids

2005 ◽  
Vol 272 (1572) ◽  
pp. 1601-1607 ◽  
Author(s):  
Yves Cherel ◽  
Keith A Hobson
Keyword(s):  
Marine Environment ◽  
Trophic Ecology ◽  
Feeding Habits ◽  
Progressive Increase ◽  
Isotopic Signature ◽  
Trophic Levels ◽  
Trophic Relationships ◽  
Dietary Shift ◽  
Giant Squid ◽  
Stable Isotopic

Cephalopods play a key role in the marine environment but knowledge of their feeding habits is limited by lack of data. Here, we have developed a new tool to investigate their feeding ecology by combining the use of their predators as biological samplers together with measurements of the stable isotopic signature of their beaks. Cephalopod beaks are chitinous hard structures that resist digestion and the stable isotope ratios of carbon (δ 13 C) and nitrogen (δ 15 N) are indicators of the foraging areas and trophic levels of consumers, respectively. First, a comparison of δ 13 C and δ 15 N values of different tissues from the same individuals showed that beaks were slightly enriched in 13 C but highly impoverished in 15 N compared with lipid-free muscle tissues. Second, beaks from the same species showed a progressive increase in their δ 15 N values with increasing size, which is in agreement with a dietary shift from lower to higher trophic levels during cephalopod growth. In the same way, there was an increase in the δ 15 N signature of various parts of the same lower beaks in the order rostrum, lateral walls and wings, which reflects the progressive growth and chitinization of the beaks in parallel with dietary changes. Third, we investigated the trophic structure of a cephalopod community for the first time. Values of δ 15 N indicate that cephalopods living in slope waters of the subantarctic Kerguelen Islands ( n =18 species) encompass almost three distinct trophic levels, with a continuum of two levels between crustacean- and fish-eaters and a distinct higher trophic level occupied by the colossal squid Mesonychoteuthis hamiltoni . δ 13 C values demonstrated that cephalopods grow in three different marine ecosystems, with 16 species living and developing in Kerguelen waters and two species migrating from either Antarctica ( Slosarczykovia circumantarctica ) or the subtropics (the giant squid Architeuthis dux ). The stable isotopic signature of beaks accumulated in predators' stomachs therefore revealed new trophic relationships and migration patterns and is a powerful tool to investigate the role of the poorly known cephalopods in the marine environment.

Trophic ecology of the chihuil sea catfish (Bagre panamensis) in the south-east Gulf of California, México

2017 ◽  
Vol 98 (4) ◽  
pp. 885-893 ◽  
Author(s):  
Víctor M. Muro-Torres ◽  
Felipe Amezcua ◽  
Raul E. Lara-Mendoza ◽  
John T. Buszkiewicz ◽  
Felipe Amezcua-Linares
Keyword(s):  
Gulf Of California ◽  
Trophic Ecology ◽  
Trophic Position ◽  
Feeding Habits ◽  
Isotope Analysis ◽  
Demersal Fish ◽  
Trophic Levels ◽  
High Plasticity ◽  
Combined Use ◽  
Ecosystem Based Fisheries Management

The trophic ecology of the chihuil sea catfish Bagre panamensis was studied through high-resolution variations in its feeding habits and trophic position (TP) in the SE Gulf of California, relevant to sex, size and season. The combined use of stomach content (SCA) and stable isotope analysis (SIA) allowed us to perform these analyses and also estimate the TP of its preys. Results of this study show that the chihuil sea catfish is a generalist and opportunistic omnivore predator that consumes primarily demersal fish and peneid shrimps. Its diet did not vary with climatic season (rainy or dry), size or sex. Results from the SIA indicated high plasticity in habitat use and prey species. The estimated TP value was 4.19, which indicates a tertiary consumer from the soft bottom demersal community in the SE Gulf of California, preying on lower trophic levels, which aids in understanding the species' trophic role in the food web. Because this species and its prey are important to artisanal and industrial fisheries in the Gulf of California, diet assimilation information is useful for the potential establishment of an ecosystem-based fisheries management in the area.

Trophic ecology of large pelagic fish in the Saint Peter and Saint Paul Archipelago, Brazil

2019 ◽  
Vol 70 (10) ◽  
pp. 1402 ◽  
Author(s):  
F. V. Albuquerque ◽  
A. F. Navia ◽  
T. Vaske ◽  
O. Crespo ◽  
F. H. V. Hazin
Keyword(s):  
Trophic Ecology ◽  
Feeding Habits ◽  
Saint Paul ◽  
Pelagic Fish ◽  
Trophic Niche ◽  
Trophic Relationships ◽  
Main Prey ◽  
Important Prey ◽  
Saint Peter ◽  
Prey Items

Trophic relationships of large pelagic predators can determine the structure and dynamics of oceanic food webs. The feeding habits and trophic ecology of five large pelagic fish (Acanthocybium solandri, Coryphaena hippurus, Elagatis bipinnulata, Thunnus albacares and Thunnus atlanticus) in the Saint Peter and Saint Paul Archipelago were evaluated to determine whether there is a trophic-niche overlap or resource partitioning among them. Eighty prey items found in 1528 stomachs were identified and grouped into Cephalopoda, Cnidaria, Crustacea, Gastropoda, Teleostei and Tunicata. Exocoetidae and Scombridae were the main prey in the diet of Acanthocybium solandri. In C. hippurus, Cheilopogon cyanopterus and Exocoetus volitans were the most important prey items, whereas C. cyanopterus was the main prey for T. albacares. Thunnus atlanticus consumed a great proportion of invertebrate species, with shrimps of Sergestidae family being particularly important. The gastropod Cavolinia sp. was the most important prey for E. bipinnulata. The five species had a high trophic specialisation and a high trophic level (>4.4), whereas most dietary overlaps were consistently low. The most important factor for diet dissimilarity was the consumption of Exocoetidade. All species were classified as top predators with varied diets, indicating their structural and functional importance in the food web of the Archipelago.

South American sea lions Otaria byronia as biological samplers of local cephalopod fauna in the Patagonian shelf marine ecosystem

2019 ◽  
Vol 99 (06) ◽  
pp. 1459-1463
Author(s):  
R. L. Bustos ◽  
G. A. Daneri ◽  
E. A. Varela ◽  
A. Harrington ◽  
A. V. Volpedo ◽  
...  
Keyword(s):  
Marine Mammals ◽  
Marine Ecosystem ◽  
Isotopic Signature ◽  
Trophic Levels ◽  
Trophic Relationships ◽  
South American ◽  
Sea Lions ◽  
Patagonian Shelf ◽  
Important Prey ◽  
Top Predators

AbstractCephalopods are important prey in the diet of top predators, such as marine mammals and seabirds. However, detailed information on their trophic relationships in the Patagonian marine ecosystem is scarce, including those cephalopod species with commercial interest. The aims of this study were to evaluate the composition of the cephalopod component in the diet of Otaria byronia and determine the habitat use and trophic levels of their main cephalopod prey by measuring the stable isotopic signature of cephalopod beaks. Between May 2005 and February 2009, fresh faecal samples were collected from two sea lions rookeries in San Matias Gulf. Cephalopods occurred in 39.4% of the 1112 samples collected during the whole period of study. The dominant prey species was Octopus tehuelchus, which occurred in 45.8% of scats containing cephalopod remains, and represented 58.7% in terms of numerical abundance and 52.0% in mass of cephalopods consumed. The second species most consumed was the myopsid Doryteuthis gahi. The significant higher δ15N values of O. tehuelchus beaks in comparison with those of D. gahi showed that these two species have different trophic levels while occupying similar habitat (δ13C values) in neritic waters of the Patagonian shelf.

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.

scholarly journals Trophic interactions of meso- and macrozooplankton and fish in the Iceland Sea as evaluated by fatty acid and stable isotope analysis

2012 ◽  
Vol 69 (7) ◽  
pp. 1277-1288 ◽  
Author(s):  
Hildur Petursdottir ◽  
Stig Falk-Petersen ◽  
Astthor Gislason
Keyword(s):  
Fatty Acid ◽  
Stable Isotope ◽  
Stable Isotope Analysis ◽  
Trophic Interactions ◽  
Trophic Ecology ◽  
Feeding Habits ◽  
Isotope Analysis ◽  
Trophic Levels ◽  
Amphipod Species ◽  
Blue Whiting

Abstract Petursdottir, H., Falk-Petersen, S., and Gislason, A. 2012. Trophic interactions of meso- and macrozooplankton and fish in the Iceland Sea as evaluated by fatty acid and stable isotope analysis. – ICES Journal of Marine Science, 69: . A trophic study was carried out in August of 2007 and 2008 on the pelagic ecosystem in the Subarctic Iceland Sea. Carbon and nitrogen stable isotopes and fatty acid biomarkers were used to study trophic linkages and the trophic ecology of the most important pelagic species in this ecosystem, with emphasis on capelin (Mallotus villosus). According to 15N enrichment results, there are 3–4 trophic levels in this ecosystem excluding organisms of the microbial loop and birds and mammals. The primarily herbivorous copepod Calanus hyperboreus occupies the lowest trophic level of the animal species studied, and adult capelin and blue whiting (Micromesistius poutassou) occupy the highest level. Calanus spp. proved to be an important dietary component of most of the species studied, the euphausiid species Thysanoessa inermis and T. longicaudata being exceptions. The chaetognath Eukrohnia hamata is a pure carnivore, feeding heavily on Calanus spp., whereas most of the other zooplankton species studied practice an omnivorous–carnivorous feeding mode. The amphipod species Themisto libellula is important in the diet of adult capelin. Adult capelin and blue whiting share the same feeding habits and could therefore be competing for food.

scholarly journals Survey of Nitrogen Isotopes of Lepomis macrochirus (Blue Gill) from Kentucky Lake Reservoir and Ledbetter Creek, Kentucky

2008 ◽  
Vol 7 (2) ◽  
Author(s):  
Rebecca Cripps ◽  
George Kipphut
Keyword(s):  
Food Source ◽  
Nitrogen Isotopes ◽  
Lepomis Macrochirus ◽  
Isotopic Signature ◽  
Trophic Relationships ◽  
Isotopic Ratios ◽  
Stable Isotopic ◽  
Kentucky Lake ◽  
Western Kentucky ◽  
Small Tributary

Previous research has shown stable isotope ratios of nitrogen in fish and other animals may vary depending on their food source. Ecologists have had some success in determining feeding and trophic relationships within an ecosystem using stable isotopic ratios. In this study, nitrogen stable isotopic ratios were measured in populations of Lepomis macrochirus (Blue Gill) in Kentucky Lake Reservoir and in a small tributary, Ledbetter Creek, in western Kentucky. The nitrogen isotopic ratios between these populations were statistically different. Even though fish are able to migrate freely between the two environments, the isotopic results suggest that the Lepomis macrochirus in Ledbetter Creek were spending enough time feeding in that environment to alter their isotopic signature. These results may lead to a better understanding of how Lepomis macrochirus utilize both stream and reservoir environments.

Trophic ecology of a tropical aquatic and terrestrial food web: insights from stable isotopes (15N)

2006 ◽  
Vol 22 (4) ◽  
pp. 469-476 ◽  
Author(s):  
Alexander Kupfer ◽  
Reinhard Langel ◽  
Stefan Scheu ◽  
Werner Himstedt ◽  
Mark Maraun
Keyword(s):  
Food Web ◽  
Trophic Ecology ◽  
Isotope Analysis ◽  
Trophic Levels ◽  
Trophic Relationships ◽  
Isotopic Signatures ◽  
Top Predators ◽  
Aquatic Vertebrates ◽  
Aquatic Food ◽  
Litter Invertebrates

We used stable isotope analysis (15N/14N) to characterize the trophic relationships of consumer communities of an aquatic food web (a permanent pond) and the adjacent terrestrial food web (secondary dry dipterocarp forest) from a seasonal tropical field site in north-eastern Thailand. In general, isotopic signatures of aquatic vertebrates were higher (δ15N range = 4.51–9.90‰) than those of invertebrates (δ15N range = 1.10–6.00‰). High 15N signatures identified water snakes and swamp eels as top predators in the pond food web. In the terrestrial food web 15N signatures of saprophagous litter invertebrates (diplopods, earthworms), termites, ants and beetle larvae were lower than in those of predatory invertebrates (scolopendrids, scorpions, whip spiders). Predatory terrestrial frogs and caecilians had lower 15N signatures than snakes, indicating that snakes are among the top predators in the terrestrial web. Based on the distribution of isotopic signatures, we estimated five trophic levels for both the aquatic and terrestrial food web. The food chains of a seasonal tropical site studied were rather short, which implies similarities to the structure of temperate food webs.

Trophic relationships and food webs of the benthic invertebrate fauna of two aseasonal tropical streams on Bougainville Island, Papua New Guinea

1996 ◽  
Vol 12 (4) ◽  
pp. 517-534 ◽  
Author(s):  
Catherine Mary Yule
Keyword(s):  
Papua New Guinea ◽  
Trophic Ecology ◽  
New Guinea ◽  
Benthic Invertebrate ◽  
Trophic Levels ◽  
Trophic Relationships ◽  
Invertebrate Fauna ◽  
Fine Particulate ◽  
Filter Feeders ◽  
Allochthonous Detritus

ABSTRACTThe trophic ecology of Konaino Creek, a small mountain headwater stream draining rainforest in the aseasonal tropics on Bougainville Island, Papua New Guinea, was examined and a food web was constructed. The major source of energy in Konaiano Creek was allochthonous detritus, most of which had been terrestrially degraded to fine particulate organic matter rather than entering the stream as leaf litter. This fine detritus was collected by the filter-feeders (mostly Simuliidae and also Hydropsychidae) which formed the dominant functional feeding group (64.4% of the fauna). Thus filterers processed most of the allochthonous detritus and made the energy available to other trophic levels, rather than shredders (1.7% of the fauna) which perform this role in temperate headwater streams. Collector-gatherers made up 22.7% of the fauna, carnivorses, mostly Odonata, Decapoda (crabs) and Hydrobiosidae, comprised 2.8% of the fauna and grazer-scrapers made up 7.4%. The latter were inhibited by low instream production owing to heavy shading and the instability and abrasion of the substrate due to frequent spates. In comparison, the trophic ecology of the nearby, coastal, Bovo River (with a catchment mainly in rainforest but mostly cleared with introduced species at the study site) was quite different and it was dominated by collector-gatherers (74%) and grazer-scrapers (15%).

scholarly journals Stable isotopes document the trophic structure of a deep-sea cephalopod assemblage including giant octopod and giant squid

2009 ◽  
Vol 5 (3) ◽  
pp. 364-367 ◽  
Author(s):  
Y. Cherel ◽  
V. Ridoux ◽  
J. Spitz ◽  
P. Richard
Keyword(s):  
Deep Sea ◽  
Trophic Structure ◽  
Trophic Position ◽  
Sperm Whale ◽  
Isotopic Signature ◽  
Trophic Levels ◽  
Sperm Whales ◽  
Giant Squid ◽  
Pelagic Habitat ◽  
Vampyroteuthis Infernalis

Although deep-sea cephalopods are key marine organims, their feeding ecology remains essentially unknown. Here, we report for the first time the trophic structure of an assemblage of these animals (19 species) by measuring the isotopic signature of wings of their lower beaks, which accumulated in stomachs of stranded sperm whales. Overall, the species encompassed a narrow range in δ 13 C values (1.7‰), indicating that they lived in closely related and overlapping habitats. δ 13 C values can be interpreted in terms of distribution with the more 13 C-depleted species (e.g. Stigmatoteuthis arcturi , Vampyroteuthis infernalis ) having a more pelagic habitat than the more 13 C-enriched, bathyal species (e.g. Todarodes sagittatus and the giant squid Architeuthis dux ). The cephalopods sampled had δ 15 N values ranging 4.6‰, which is consistent with the species spanning approximately 1.5 trophic levels. Neither the giant octopod ( Haliphron atlanticus ) nor the giant squid reached the highest trophic position. Species δ 15 N was independent of body size, with large squids having both the highest ( Taningia danae ) and lowest ( Lepidoteuthis grimaldii ) δ 15 N values. Their trophic position indicates that some species share the top of the food web, together with other megacarnivores such as the sperm whale.

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