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Arild Folkvord - One of the best experts on this subject based on the ideXlab platform.
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Prey selectivity in piscivorous bluefin tuna larvae reared in the laboratory
Journal of Plankton Research, 2014Co-Authors: Patricia Reglero, Aurelio Ortega, Fernando De La Gándara, F. Javier Viguri, Manabu Seoka, Øyvind Fiksen, E Blanco, Arild FolkvordAbstract:Prey Size selectivity in piscivorous fish larvae is important to both aquaculture and fisheries science, but laboratory experiments are few. We analyzed selective foraging in Atlantic bluefin tuna larvae ( Thunnus thynnus) using two larval fish Prey species. The experiments revealed that selective foraging of Prey Sizes differed among bluefin tuna predator Sizes (15–25 mm SL) and Prey species, bonito ( S arda sarda ) and seabream ( Sparus aurata ). The observed pattern suggest a general preference for small bonito Prey larvae but large seabream Prey. Thus, Prey Size alone is not the only trait responsible for Size selectivity in piscivorous fish larvae.
Enric Saiz - One of the best experts on this subject based on the ideXlab platform.
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feeding behaviour of the nauplii of the marine calanoid copepod paracartia grani sars functional response Prey Size spectrum and effects of the presence of alternative Prey
PLOS ONE, 2017Co-Authors: Laura Kristiina Helenius, Enric SaizAbstract:Laboratory feeding experiments were conducted to study the functional response and Prey Size spectrum of the young naupliar stages of the calanoid copepod Paracartia grani Sars. Experiments were conducted on a range of microalgal Prey of varying Sizes and motility patterns. Significant feeding was found in all Prey of a Size range of 4.5-19.8 μm, with Holling type III functional responses observed for most Prey types. The highest clearance rates occurred when nauplii fed on the dinoflagellate Heterocapsa sp. and the diatom Thalassiosira weissflogii (respectively, 0.61 and 0.70 mL ind-1 d-1), suggesting an optimal Prey:predator ratio of 0.09. Additional experiments were conducted to examine the effects of the presence of alternative Prey (either Heterocapsa sp. or Gymnodinium litoralis) on the functional response to the haptophyte Isochrysis galbana. In the bialgal mixtures, clearance and ingestion rates of I. galbana along the range of the functional response were significantly reduced as a result of selectivity towards the larger, alternative Prey. Paradoxically, relatively large Prey trigger a perception response in the nauplii, but most likely such Prey cannot be completely ingested and a certain degree of sloppy feeding may occur. Our results are further evidence of the complex Prey-specific feeding interactions that are likely to occur in natural assemblages with several available Prey types.
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intra and interspecific variability in Prey Size and niche breadth of myctophiform fish larvae
Marine Ecology Progress Series, 2000Co-Authors: Ana Sabates, Enric SaizAbstract:Prey Size is one of the major factors involved in Prey selection of fish larvae, and is closely related to their foraging abilities and mouth Size. This study examines the feeding habits of 6 coexisting fish larvae species of the order Myctophiformes in the western Mediterranean. The Myctophiformes are the dominant teleosts of the open oceans worldwide, and their larvae are char- acterized by high morphological variability. In the present study, Size of ingested Prey increased through larval development for all species examined, but at different rates. Niche breadth (i.e. range of Sizes of ingested Prey, estimated as the standard deviation of log-transformed Prey Sizes) was con- stant throughout growth. The larvae actively selected certain Prey Sizes; selection changed during development, and varied between species. This variability appears to be related to interspecific morphological differences, and may constitute a strategy to optimize the utilization of trophic resources in the oligotrophic open-ocean habitat.
Thomas Kiorboe - One of the best experts on this subject based on the ideXlab platform.
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mechanisms of Prey Size selection in a suspension feeding copepod temora longicornis
Marine Ecology Progress Series, 2014Co-Authors: Rodrigo J Goncalves, Hans Van Someren Greve, Damien Florian Couespel, Thomas KiorboeAbstract:We examined Size-dependent Prey detection and Prey capture in free-swimming Temora longicornis using video observations, particle image velocimetry (PIV), and bottle incuba- tions with phytoplankton Prey Sizes within the range 6�60 µm equivalent spherical diameter (ESD). T. longicornis generates feeding currents by oscillating its appendages at about 25 Hz. Prey cells >10 µm ESD are perceived and captured individually. A capture response was elicited when Prey was touched by (or within a few cell radii from) the setae on the feeding appendages. The extension of the setae defines the Prey encounter cross section, which is therefore independent of Prey Size. The flux of water through the encounter area, estimated from PIV, was ca. 150 ml ind. �1 d �1 , which represents the maximum possible clearance rates and was similar to that estimated in incubation experiments. However, while the detection probability was nearly 100% for cells >10�15 µm, it declined rapidly for smaller cells. Conversely, the probability that a cell which elicited a capture response was actually ingested declined with increased cell Size, from nearly 100% for small cells, to ~0% for the largest cells examined. The resulting Prey Size spectrum, pre- dicted as the product of the cell-Size-specific encounter rates and capture probabilities, was dome- shaped, with a maximum around 20�30 µm ESD. The Prey Size spectrum from incubation ex - periments had a similar shape and an optimum range of 30�50 µm ESD. The mechanistic underpinning of the Prey Size spectrum suggested here deviates from previous descriptions mainly in the mechanism and range of Prey detection.
Frederick S Scharf - One of the best experts on this subject based on the ideXlab platform.
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contrasting patterns of resource utilization between juvenile estuarine predators the influence of relative Prey Size and foraging ability on the ontogeny of piscivory
Canadian Journal of Fisheries and Aquatic Sciences, 2009Co-Authors: Frederick S Scharf, Francis Juanesf Juanes, Jeffrey A BuckelAbstract:In aquatic systems, ontogenetic patterns of resource utilization strongly influence growth and survival, particu- larly during early life stages. We compared Prey resource use and evaluated potential factors affecting the timing of the shift to piscivorous feeding in two juvenile estuarine fish predators: striped bass (Morone saxatilis) and bluefish (Poma- tomus saltatrix). In New York Bight estuaries, bluefish shift to piscivory earlier in ontogeny and consume larger relative Prey fish Sizes compared with striped bass. Predator gape allometries are similar and did not determine maximum Prey Sizes eaten. Experimental results revealed marked differences in foraging abilities between predators, with bluefish realiz- ing much greater foraging efficiency compared with striped bass feeding on identical fish Prey. Both predators demon- strated lower feeding efficiency and grew relatively poorly when feeding on invertebrates compared with fish Prey. When held together under limited Prey conditions, bluefish exploited a greater proportion of available Prey at the expense of striped bass. Our findings highlight the importance of the availability of appropriately Sized forage fishes to the ontogeny of piscivory and provide evidence that predator-Prey Size relationships and disparate foraging abilities can generate inter- and intra-specific variation in patterns of resource utilization and predator growth. Resume´ : Dans les systemes aquatiques, les patrons ontogeniques d'utilisation des ressources influencent fortement la croissance et la survie, particulierement durant les premiers stades de la vie. Nous comparons l'utilisation des ressources en proies et evaluons les facteurs potentiels qui affectent le moment du changement vers un regime alimentaire piscivore chez deux jeunes poissons predateurs estuariens, le bar raye´ (Morone saxatilis) et le tassergal (Pomatomus saltatrix). Dans les estuaires du golfe de New York, les tassergals deviennent piscivores plus tot dans leur ontogenie et consomment des proies de taille relativement plus grande que les bars rayes. Les allometries de l'ouverture de la bouche sont semblables et ne determinent pas la taille maximale de proie consommee. Des donnees experimentales indiquent des differences mar- quees dans l'habiletede recherche de nourriture entre ces predateurs et les tassergals atteignent une efficacitede recherche de nourriture beaucoup plus grande que celle des bars rayes qui se nourrissent des memes poissons proies. Lorsqu'ils s'ali- mentent d'invertebres plutot que de poissons, les deux predateurs montrent une efficacitealimentaire reduite et croissent relativement mal. Gardes ensemble en presence de proies limitees, les tassergals exploitent une proportion plus elevee des proies disponibles au detriment des bars rayes. Nos resultats soulignent l'importance de la disponibilitede poissons fourr- age de taille adequate dans l'ontogenie de l'ichtyophagie et demontrent que les relations de taille entre les predateurs et les proies, ainsi que les differences d'habiletede recherche de nourriture, peuvent produire des variations inter- et intra- specifiques dans les patrons d'utilisation des ressources et la croissance des predateurs. (Traduit par la Redaction)
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predator Size Prey Size relationships of marine fish predators interspecific variation and effects of ontogeny and body Size on trophic niche breadth
Marine Ecology Progress Series, 2000Co-Authors: Frederick S Scharf, Francis Juanes, Rodney A RountreeAbstract:We utilized a long-term data base collected over a broad geographic range to examine predator Size - Prey Size relationships for 18 species of marine fish predators from continental shelf waters off the northeast US coast. Regression analysis was used to illustrate interspecific variation in ontogenetic patterns of Prey Size use, gape allometries, and ratio-based trophic niche breadths. Size- based feeding strategies were assessed through comparison of frequency distributions of relative Prey Sizes eaten and were related to general predator feeding tactics and gape morphology. The results demonstrated that the range of Prey Sizes eaten expanded with increasing predator body Size for each of the marine predators examined, leading to asymmetric predator Size - Prey Size distribu- tions. Absolute maximum Prey Size and slopes of maximum Prey Size versus predator Size varied widely among predator taxa. Distinct Size-based feeding strategies were evident, as diets of some predators were dominated by Prey that were 10 to 20% of predator Size, whereas other predators frequently consumed Prey >50% of predator Size. Gape Sizes and allometric relationships with body Size were also diverse among predators and often were closely associated with maximum Prey Sizes. Ratio-based trophic-niche breadths generally did not expand with predator ontogeny and tended to narrow for the largest predators, which may be common for animal taxa.
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feeding habits of red drum sciaenops ocellatus in galveston bay texas seasonal diet variation and predator Prey Size relationships
Estuaries, 2000Co-Authors: Frederick S Scharf, Kurtis K SchlichtAbstract:Feeding habits, seasonal diet variation, and predator Size-Prey Size relationships of red drum (Sciaenops ocellatus) were investigated in Galveston Bay, Texas through stomach contents analysis. A total of 598 red drum ranging from 291–763 mm total length were collected and their stomach contents analyzed during fall 1997 and spring 1998. The diet of red drum showed significant seasonal patterns, and was dominated by white shrimp (Penaeus setiferus) during fall and gulf menhaden (Brevoortia patronus) during spring. Blue crab (Callinectes sapidus) was an important component of red drum diets during both seasons. Significant differences existed between Prey types consumed during fall and spring as red drum diet reflected seasonal variation in Prey availability. Predictive regression equations were generated to estimate original carapace width of blue crabs from several measurements taken from carapace fragments recovered in red drum stomachs. Regressions were highly significant (r2>0.97) and increased the number of blue crabs with Size information nearly three fold. Predator Size-Prey Size relationships were determined for red drum feeding on white shrimp, gulf menhaden, and blue crab. Although regression slopes were statistically significant, Prey Sizes increased only slightly with increasing red drum Size. Comparisons of Prey Sizes consumed by red drum with Sizes occurring in the field indicate that red drum feed in nearshore shallow water habitats, which serve as nursery areas for many juvenile fishes and crustaceans. Our findings demonstrate that red drum feed on several Prey species of commercial and recreational value and may have important effects on estuarine community structure.
Patricia Reglero - One of the best experts on this subject based on the ideXlab platform.
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Prey selectivity in piscivorous bluefin tuna larvae reared in the laboratory
Journal of Plankton Research, 2014Co-Authors: Patricia Reglero, Aurelio Ortega, Fernando De La Gándara, F. Javier Viguri, Manabu Seoka, Øyvind Fiksen, E Blanco, Arild FolkvordAbstract:Prey Size selectivity in piscivorous fish larvae is important to both aquaculture and fisheries science, but laboratory experiments are few. We analyzed selective foraging in Atlantic bluefin tuna larvae ( Thunnus thynnus) using two larval fish Prey species. The experiments revealed that selective foraging of Prey Sizes differed among bluefin tuna predator Sizes (15–25 mm SL) and Prey species, bonito ( S arda sarda ) and seabream ( Sparus aurata ). The observed pattern suggest a general preference for small bonito Prey larvae but large seabream Prey. Thus, Prey Size alone is not the only trait responsible for Size selectivity in piscivorous fish larvae.
