Larval sand lance (Ammodytes sp.) in the diet of small juvenile wolffish (Anarhichas spp.): predatory interactions in frontal water masses off western Greenland

2002 ◽  
Vol 59 (11) ◽  
pp. 1759-1767 ◽  
Author(s):  
Peter Munk
Keyword(s):  
Fish Larvae ◽  
Stomach Contents ◽  
Prey Type ◽  
Ontogenetic Changes ◽  
Sand Lance ◽  
Larval Size ◽  
Predatory Behaviour ◽  
Dietary Shift ◽  
Abundance Estimates ◽  
Anarhichas Lupus

The predatory behaviour of two species of juvenile wolffish (Anarhichas lupus and Anarhichas minor) was studied during a field campaign across a frontal area off western Greenland. The study focused on ontogenetic changes in prey-type and -size preference of the wolffish and their predatory impact on a cohabiting population of larval sand lance (Ammodytes sp.). Sampling took place along a cross-shelf transect at latitude 66°20' N, and the analysis is based on stomach contents of assembled wolffish (2–5 cm in length) and abundance estimates of plankton and fish. An ontogenetic change in wolffish prey preference was evident as a dietary shift from copepods and smaller amphipods to larger amphipods and fish larvae. The inclusion of fish larvae in the wolffish diet led to a marked increase in prey biomass, and fish larvae constituted up to 77% of diet biomass in the largest juveniles caught. Wolffish selectively targeted the smaller-sized part of the larval sand lance population; hence, larval vulnerability increased with decreasing size. Comparison between estimated predation rates and abundances of predator and prey indicated larval predation mortalities of up to 5% per day, with mortality peaking in the vicinity of a hydrographic front. Hence, findings suggest substantial predation pressure on larvae, primarily related to larval size and distribution.

scholarly journals Ontogenetic shift in diet of a large elapid snake is facilitated by allometric change in skull morphology

2021 ◽  
Author(s):  
Matthew Brenton Patterson ◽  
Ashleigh K Wolfe ◽  
Patricia A Fleming ◽  
Philip W Bateman ◽  
Meg Martin ◽  
...  
Keyword(s):  
Body Size ◽  
Morphological Changes ◽  
Full Range ◽  
Stomach Contents ◽  
Prey Type ◽  
Postnatal Ontogeny ◽  
Shape Variation ◽  
Ontogenetic Changes ◽  
Skull Morphology ◽  
Skull Shape

Abstract As snakes are limbless, gape-limited predators, their skull is the main feeding structure involved in prey handling, manipulation and feeding. Ontogenetic changes in prey type and size are likely to be associated with distinct morphological changes in the skull during growth. We investigated ontogenetic variation in diet from stomach contents of n = 161 dugite specimens (Pseudonaja affinis, Elapidae) representing the full range of body size for the species, and skull morphology of 46 specimens (range 0.25–1.64 m snout-vent-length; SVL). We hypothesised that changes in prey type throughout postnatal ontogeny would coincide with distinct changes in skull shape. Dugites demonstrate a distinct size-related shift in diet: the smallest individuals ate autotomised reptile tails, medium-sized individuals predominantly ate small reptiles (as snakes grew larger there was an increased likelihood of feeding on reptiles head-first), and the largest individuals (> 0.8 m SVL) ate mammals and large reptiles. Morphometric analysis revealed that ~ 40% of the variation in skull shape was associated with body size (SVL). Through ontogeny, skulls changed from a smooth, bulbous cranium with relatively small trophic bones (upper and lower jaws and their attachments), to more rugous bones (as an adaption for muscle attachment) and relatively longer trophic bones that would extend gape. Individual shape variation in trophic bone dimensions was greater in larger adults and this likely reflects natural plasticity of individuals feeding on different prey sizes/types. Rather than a distinct morphological shift with diet, the ontogenetic changes were consistent, but positive allometry of individual trophic bones resulted in disproportionate growth of the skull, reflected in increased gape size and mobility of jaw bones in adults to aid the ingestion of larger prey and improve manipulation and processing ability. These results indicate that allometric scaling is an important mechanism by which snakes can change their dietary niche.

Brief description of prey selectivity and ontogenetic changes in the diet of the invasive lionfish Pterois volitans (Actinopterygii, Scorpaenidae) in the Mexican Caribbean

2018 ◽  
Author(s):  
Juan Carlos Villaseñor-Derbez
Keyword(s):  
Stomach Contents ◽  
Ontogenetic Change ◽  
Prey Selectivity ◽  
Ontogenetic Changes ◽  
Pterois Volitans ◽  
Mexican Caribbean ◽  
Invasive Lionfish

Stomach contents were analyzed from 109 individuals. A total of 4 Genera and 14 Species were identified. Crustaceans accounted for %N=67.39% , %IRI= 86.37% of the total identified taxa and Teleosts %N=32.61% (%IRI = 13.63%). An ontogenetic change was observed in P. volitans diet.

Diet and feeding strategy of thornback ray, Raja clavata (Chondrichthyes: Rajidae) from the Gulf of Gabes (Tunisia—Central Mediterranean Sea)

2014 ◽  
Vol 94 (7) ◽  
pp. 1509-1516 ◽  
Author(s):  
Hasna Kadri ◽  
Sondes Marouani ◽  
Mohamed Nejmeddine Bradai ◽  
Abderrahmen Bouaïn
Keyword(s):  
Feeding Strategy ◽  
Stomach Contents ◽  
Ontogenetic Changes ◽  
Central Mediterranean ◽  
Gulf Of Gabes ◽  
Gulf Of Gabès ◽  
Thornback Ray ◽  
Raja Clavata ◽  
Food And Feeding ◽  
Quantitative Analyses

Food and feeding strategy of the thornback ray, Raja clavata, were studied from stomach contents analysis of specimens caught monthly in the Gulf of Gabes. The data were analysed according to sex, size and season. At total of 1280 stomachs was examined, from specimens ranging from 14 to 110 cm total length (TL), of which 1076 (83.98%) contained food. Thornback ray feed mainly on teleosts, crustaceans and cephalopods, whereas gastropods and polychaetes are occasionally consumed. Significant differences were found between the diets of males and females; however, ontogenetic changes were also detected, with crustaceans constituting the greatest proportion of the diet of smaller rays. Both teleosts and cephalopods increased in importance with growth of the skates. Prey diversity increased with size; large and mobile prey species were more commonly found in the diet of larger skates. Diet composition showed seasonal variations. Quantitative analyses and graphical methods indicate that the thornback ray is a generalist feeder.

Répartition des ressources et changements saisonniers de l'alimentation d'ombles de fontaine anadromes, Salvelinus fontinalis

1982 ◽  
Vol 60 (12) ◽  
pp. 3068-3070 ◽  
Author(s):  
Alain Gaudreault ◽  
Martin Castonguay ◽  
Gérard J. FitzGerald
Keyword(s):  
Resource Partitioning ◽  
Salvelinus Fontinalis ◽  
Stomach Contents ◽  
Prey Type ◽  
Brook Charr ◽  
Lower Estuary ◽  
First Time ◽  
Winter Feeding

Resource partitioning among anadromous brook charr in an estuary included habitat and prey-type partitioning. In spring and summer, juveniles were foraging in the upper estuary on crustacea and insects while adults were eating crustacea and fish in the lower estuary. In the fall, adult charr, which were all in the river, ate little. During winter, adult charr were found in the estuary and consumed crustacea and only a few fish. The relative weights of stomach contents were similar in summer and winter, showing for the first time the importance of winter feeding for this species.

scholarly journals Rapid quantitative assessment of fish larvae community composition using metabarcoding

2020 ◽  
Author(s):  
Frances C. Ratcliffe ◽  
Tamsyn M. Uren Webster ◽  
Deiene Rodriguez-Barreto ◽  
Richard O’Rorke ◽  
Carlos Garcia de Leaniz ◽  
...  
Keyword(s):  
Community Composition ◽  
Early Life ◽  
High Throughput Sequencing ◽  
Fish Larvae ◽  
Morphological Identification ◽  
Taxon Richness ◽  
Life Stages ◽  
Early Life Stages ◽  
Abundance Estimates ◽  
Family Level

AbstractClimate change stressors greatly impact the early life-stages of many organisms but their cryptic morphology often renders them difficult to monitor using morphological identification. High-throughput sequencing of DNA amplicons (metabarcoding) is potentially a rapid and cost-effective method to monitor early life-stages for management and environmental impact assessment purposes. Yet, there is conflicting information about the quantitative capability of metabarcoding. We compared metabarcoding with traditional morphological identification to evaluate taxonomic precision and reliability of abundance estimates, using 332 fish larvae from multinet hauls (0-50m depth) collected at 14 offshore sampling sites in the Irish and Celtic seas. To improve relative abundance estimates, the amount of tissue for each specimen was standardised and mitochondrial primers with conserved binding sites were used. Family level correction factors for amplification bias and back-calculations were applied to estimate numbers of individuals of a given taxon in a sample. Estimates from metabarcoding reads and morphological assessment were positively correlated for relative family abundances as well as taxon richness (Rs=0.81, P=0.007) and diversity (Rs=0.88, P=0.003). After applying family level correction, back-estimates of the number of individuals per family within a sample were accurate to ± 2 individuals. Spatial patterns of community composition did not differ significantly between metabarcoding and morphological assessments.Our results show that DNA metabarcoding of bulk tissue samples can be used to monitor changes in fish larvae abundance and community composition. This represents a feasible, efficient and faster alternative to morphological identification that can be applied to terrestrial and aquatic habitats.

scholarly journals Feeding habits of Lithobates megapoda (Anura: Ranidae), a threatened leopard frog used for human consumption, in Lake Chapala, Mexico

2021 ◽  
Vol 20 (1) ◽  
pp. 75-88
Author(s):  
José Luis Barragán-Ramírez ◽  
Benjamín Hernández ◽  
María Guadalupe Velarde-Aguilar ◽  
Oscar Pérez-Flores ◽  
José Luis Navarrete-Heredia ◽  
...  
Keyword(s):  
Trophic Ecology ◽  
Dietary Diversity ◽  
Feeding Habits ◽  
Stomach Contents ◽  
Prey Type ◽  
Leopard Frog ◽  
Human Consumption ◽  
Relative Importance ◽  
Prey Category ◽  
Lake Chapala

The Big-footed Leopard Frog (Lithobates megapoda) is a threatened and endemic species from western Mexico. This species has aquatic habits and it is distinguished by its large size, particularly by the length of its legs, reason for which it is captured for human consumption. Also, knowledge about its natural history is scarce and incomplete. In this study, we analyzed the composition of the diet of L. megapoda on the shore of Lake Chapala, the largest lake in Mexico. A total of 69 adult individuals were collected lifeless in fishing nets, during the rainy season (June-October), of which 48 had stomach contents. A total of 96 prey items were identified, which correspond to 13 prey categories. Fish constituted the most dominant prey category in the diet in terms of number, volume, frequency of occurrence, and relative importance. No significant differences were found in the consumption by prey type (aquatic or terrestrial). However, the aquatic preys had a greater relative importance and were more voluminous than the terrestrial ones. The diversity of prey categories, in terms of prey volume, indicates males may have a higher dietary diversity than females, but we not evaluated possible bias. In addition, a significant effect was found in the interaction of size (SVL) of frogs with the average of prey volume. Females (that are larger than males) consumed prey within a wide volume range and, the larger they are, more voluminous are prey. In this way it is possible that intraspecific competition for trophic resources in the environment is reduced. This study helps us understand the trophic ecology of L. megapoda, a frog species that plays an important role in the food web where it lives, as a predator feeding on aquatic and terrestrial organisms.

Do snakes exhibit shifts in feeding ecology associated with the presence or absence of potential competitors? A case study from tropical Africa

2003 ◽  
Vol 81 (2) ◽  
pp. 228-236 ◽  
Author(s):  
Luca Luiselli
Keyword(s):  
Feeding Ecology ◽  
Prey Size ◽  
Prey Type ◽  
Swamp Forest ◽  
Southeastern Nigeria ◽  
Predator Species ◽  
Predatory Behaviour ◽  
Ecological Requirements ◽  
Predator Size ◽  
Potential Competitor

Two species of rain-forest snakes, the colubrids Natriciteres fuliginoides and Natriciteres variegata, are potential competitors, because they attain, on average, the same body size (20–30 cm long), have similar habits and ecological requirements (they are both diurnal and nocturnal, often semi-aquatic), and have similar dietary spectra ( including both small vertebrates and invertebrates). I studied prey type and predator size – prey size relationships of these snakes in four swamp-forest areas of southeastern Nigeria (West Africa): only N. fuliginoides was found in two of these areas, whereas both species were common in the other two areas. The feeding ecology of N. fuliginoides shifted greatly in the presence of its potential competitor, N. variegata, in terms of prey-type preferences and predatory behaviour as well as in terms of predator size – prey size relationships. In particular, the effects of the potential competitor on the feeding ecology of N. fuliginoides were (i) a shift toward eating many invertebrates from a diet based on many small vertebrates, (ii) a shift toward eating many terrestrial organisms from a diet based on many aquatic organisms, and (iii) a shift in mean prey size for females toward relatively larger prey from a diet based on smaller prey. The resulting effect was a clear partitioning of food resources between the two predator species in both the areas where they are sympatric, whereas N. fuliginoides had a wider dietary spectrum (covering that of the two species together) in the areas where its competitor is not found. The role of intraspecific competition seems less strong, as no apparent resource partitioning in prey type or prey size was observed between males and females of either species or in any study area. However, mean prey size was significantly greater for females than for males of both species and in all study areas, but depended on the significant reverse sexual size dimorphism observed in both species.

Feeding habits and trophic status of Merluccius hubbsi along the northernmost limit of its distribution in the South-western Atlantic

2019 ◽  
Vol 99 (06) ◽  
pp. 1399-1408
Author(s):  
Paulo A. S. Costa ◽  
Adriana C. Braga ◽  
Giovanna S. Malavolti ◽  
Marcos A. L. Franco ◽  
Pedro V. Gatts ◽  
...  
Keyword(s):  
Total Mercury ◽  
Trophic Status ◽  
Feeding Habits ◽  
Stomach Contents ◽  
Generalist Predator ◽  
Isotopic Niche ◽  
Benthic Fish ◽  
Ontogenetic Changes ◽  
Western Atlantic ◽  
Feeding Plasticity

AbstractStomach contents analysis and stable isotope results indicate M. hubbsi is a generalist predator that feeds mainly on demersal fishes, followed by crustaceans and cephalopods. Ontogenetic changes in diet were identified, with fish importance increasing in the diet with hake size. Smaller hake (<250 mm) fed mostly on the sepiolid Semirossia tenera (89.45%IRI) and engraulid fish (89.96%IRI). Mid-sized hake (250–300 mm) fed mainly on benthic fish such as Bellator brachychir (95.63%IRI) and euphausiids (56.46%IRI), while larger hake (>300 mm) fed heavily on Dactylopterus volitans (94.80%IRI) and occasionally on a variety of teleosts. Significant correlations between δ13C (P < 0.05), THg (P < 0.001) and hake size occurred, whereas no relationship was observed between δ15N and hake size or δ15N and total mercury. Signatures were lowest in smaller hake with a tendency of increasing with size. Smaller and larger hake were significantly different in δ13C. Differences regarding isotopic niche width were quantified for each size group; trophic diversity and trophic redundancy among them were negligible, but hake >300 mm possibly have a larger feeding plasticity due to the combination of prey from a wide trophic level range.

Diet of the spiny lobster Palinurus elephas (Decapoda: Palinuridea) from the Columbretes Islands Marine Reserve (north-western Mediterranean)

2001 ◽  
Vol 81 (2) ◽  
pp. 347-348 ◽  
Author(s):  
Raquel Goñi ◽  
Antoni Quetglas ◽  
Olga Reñones
Keyword(s):  
Diet Composition ◽  
Sea Urchins ◽  
Marine Reserve ◽  
Spiny Lobster ◽  
Stomach Contents ◽  
Western Mediterranean ◽  
Ontogenetic Changes ◽  
Progressive Reduction ◽  
North Western ◽  
Palinurus Elephas

Stomach contents of 382 Palinurus elephas collected in the Columbretes Islands Marine Reserve (north-western Mediterranean) were examined to study the diet and to assess ontogenetic and sex related differences in feeding regime. Molluscs, crustaceans, and sea urchins were the most common prey. Diet composition varied with lobster size but not with sex. Ontogenetic changes in diet were reflected in the progressive reduction of the contribution of gastropods and crustaceans and in the increased importance of other prey such as fish.

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