Seasonal variations in the energy density of fishes in the North Sea

Pedersen, Jannik Nedergaard; Hislop, J. R. G.

doi:10.1111/j.1095-8649.2001.tb00137.x

Cited by 100 publications

(72 citation statements)

References 25 publications

(33 reference statements)

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“…Pedersen and Hislop 2001). The dominance of capelin and sandeels in the chick diet was corroborated by a contemporary but independent survey on Hornøya in which 75% of 1,360 fish observed being brought into the colony were capelin, 16% sandeel, 6% herring and 2% ''other'' (R.T. Barrett, personal observation).…”

Section: Discussionmentioning

confidence: 76%

Optimal foraging in chick-raising Common Guillemots (Uria aalge)

2010

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The Norwegian population of the Common Guillemot Uria aalge has declined by [95% since the 1960s, and is classified as critically endangered in the Norwegian Red List. Much of the recent decline has been attributed to reduced food availability, but without extensive documentation of adult diet. Instead, chick diet has been considered a proxy of adult diet during the breeding season in many Norwegian studies. However, central-place foraging theory, especially for single-prey loaders, predicts that this may not be so, and this study directly compares the diet of adult and chick Common Guillemots during the breeding season at a colony in NE Norway. Whereas chicks were fed mainly capelin (Mallotus villosus) and sandeels (Ammodytes sp.), most of the adult diet consisted of the two youngest year classes of Gadidae, probably cod (Gadus morhua) and haddock (Melanogrammus aeglefinus). A successful ecosystem management of seabirds is dependent on a full understanding of how prey quality, abundance and availability influence seabird populations and their viability, such that knowing the true diet of adult Common Guillemots has important implications in the modelling and management of the Norwegian populations.

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Section: Discussionmentioning

confidence: 76%

Optimal foraging in chick-raising Common Guillemots (Uria aalge)

2010

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“…In spring, large-sized sprat had slightly higher TFI than smaller individuals. Reproduction has been reported to influence feeding in fish, and the metabolic demand is typically high immediately after spawning (Pedersen & Hislop 2001), resulting in enhanced food consumption in mature sprat during spring. In the autumn, sprat !10 cm had low feeding activity, indicated by low TFI ( Figure 5A), and high proportions of empty stomachs in November 2009 and October 2010 (Table II).…”

Section: Feeding Activitymentioning

confidence: 99%

Diet composition and food selectivity of sprat (Sprattus sprattus) in Hardangerfjord, Norway

Falkenhaug

Dalpadado

2013

Marine Biology Research

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The diet composition and prey selection of sprat (Sprattus sprattus) was studied in the Hardangerfjord, western Norway during four cruises in spring and autumn of 2009 and 2010. Feeding activity, indicated by stomach fullness, varied with sprat size, season and time of day. Small-sized sprat were found to feed both in spring and autumn, while the larger individuals had lower feeding activity late in the season. Diurnal variation in stomach fullness was observed in the autumn but not in spring. Sprat fed on a broad diversity of prey types, including copepods, phytoplankton and meroplankton. Multivariate statistical analysis suggested that the dietary composition of sprat differed significantly between years, seasons and among areas within the fjord. During spring, phytoplankton and invertebrate eggs dominated the diet, while copepods were most important in the autumn. Positive selection was found for Microsetella norvegica and euphausiid eggs, which were the most frequently occurring prey in stomachs, followed by Oithona and Acartia spp. Interannual variability in zooplankton abundance in the fjord, related to physical processes, may have a large impact on the feeding conditions for fjord populations of sprat.

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“…-0.86 (Andersen, 2001), where Ei is energy density of the prey in kJ/g taken from Pedersen and Hislop (2001 …”

Section: A3mentioning

confidence: 99%

Functional and aggregative response of North Sea whiting

Rindorf

Gislason

2005

Journal of Experimental Marine Biology and Ecology

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15The functional response of whiting (Merlangius merlangus L.) to clupeid and gadoid prey was determined from estimates of food intake and prey density at five locations in the North Sea. The intake of most prey types was well described by a type II (decelerating) response, although in some cases a type III (sigmoid) response provided a slightly better fit. Though a saturation level was reached for all types of 20 fish prey, none of the levels corresponded to the maximum digestive capacity of the predator. This was not caused by ingestion of other prey as the amount of other food and fish prey ingested were not negatively correlated. An investigation of the occurrence of fresh fish in the stomachs revealed that fish was ingested almost 2 exclusively during dawn and dusk and the lack of negative correlation between the 25 intake of fish and other prey may thus be a result of the limited time in which fish prey was vulnerable to predation. No aggregative response of the predators was detected towards any of the prey and catches of prey and predators were slightly negatively correlated. There was evidence of an increase in mortality with density at low clupeid densities, but mortality decreased to virtually zero at high densities. 30Whiting seem therefore unlikely to impose a regulatory effect on their fish prey outside a narrow range of prey densities.

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Seasonal variations in the energy density of fishes in the North Sea

Cited by 100 publications

References 25 publications

Optimal foraging in chick-raising Common Guillemots (Uria aalge)

Optimal foraging in chick-raising Common Guillemots (Uria aalge)

Diet composition and food selectivity of sprat (Sprattus sprattus) in Hardangerfjord, Norway

Functional and aggregative response of North Sea whiting

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