Dietary and seasonal variability in trophic relations at the base of the North Sea pelagic food web revealed by stable isotope and fatty acid analysis

AbstractSeabird movements and diet during the non-breeding season are poorly studied, yet understanding these aspects of seabird ecology is extremely important to effectively conserve these protected species. Stable isotope analyses (SIA) provide a cost-effective solution to filling these knowledge gaps, yielding information on diet and foraging locations of animals. This study aimed to use SIA to investigate whether Common Guillemots (Uria aalge) from different age classes and locations in the UK had contrasting diets and foraging areas during the post-breeding moult (July-September). SIA of secondary feathers and a newly-developed North Sea isoscape were used to identify the likeliest foraging areas and diets of deceased guillemots recovered from beaches in eastern Scotland and mixed fisheries in Cornwall and the Celtic Sea. Overall, guillemots foraged widely in the western, eastern and southern North Sea, consuming a variety of clupeid, gadoid and invertebrate prey. There were negligible dietary differences between age classes and birds from different recovery locations. Juveniles showed a wider range in foraging areas, but both age classes foraged in similar parts of the North Sea. Guillemots recovered from Scotland may have foraged further north, only overlapping with guillemots recovered from the southwestern UK in the southern and eastern North Sea. Their winter recovery locations also implied that they exhibited different movement strategies during the non-breeding season, meriting further investigation. Conservation efforts should target foraging areas in the southern and eastern North Sea which are highly threatened by gillnet fishing, shipping traffic and oil infrastructure.

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Assimilation of marine-derived nutrients from anadromous Rainbow Smelt in an eastern North American riverine food web: evidence from stable-isotope and fatty acid analysis

Freshwater Science ◽

10.1086/700598 ◽

2018 ◽

Vol 37 (4) ◽

pp. 747-759 ◽

Cited By ~ 1

Author(s):

Sean J. Landsman ◽

Kurt M. Samways ◽

Brian Hayden ◽

Kyle M. Knysh ◽

Michael R. van den Heuvel

Keyword(s):

Fatty Acid ◽

Stable Isotope ◽

Food Web ◽

North American ◽

Fatty Acid Analysis ◽

Rainbow Smelt ◽

Marine Derived Nutrients

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Feeding, Growth and Reproduction of the Marine Planktonic Copepod Pseudo-Calanus Elongatus Boeck

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315400018956 ◽

1976 ◽

Vol 56 (2) ◽

pp. 327-344 ◽

Cited By ~ 100

Author(s):

G.-A. Paffenhöfer ◽

R. P. Harris

Keyword(s):

Food Web ◽

North Sea ◽

Calanoid Copepods ◽

Small Copepod ◽

The North ◽

Controlled Conditions ◽

Food Concentrations ◽

Food Species ◽

The North Sea ◽

Growth And Reproduction

INTRODUCTIONThe development of techniques to culture calanoid copepods over multiple generations in the laboratory has resulted in considerable advances in knowledge about a group of animals of major importance in the marine food web. A series of extensive studies have been made of two species of large calanoids, Calanus helgolandicus (Claus) (Mullin & Brooks, 1967, 1970a, 1970b; Paffenhöfer, 1970, 1971, 1976a, 1976b), and Rhincalanus nasutus Giesbrecht (Mullin & Brooks, 1967, 1970a, 1970b). Feeding, growth, and reproduction have been studied under controlled conditions, using different temperatures, food species, and food concentrations. Some of the information gained in these studies has been incorporated into a simulation model of the planktonic ecosystem of the North Sea (Steele, 1974). However, in the North Sea and in many other sea areas species of small copepod probably form an important component of the food web. Little information is available on the quantitative biology of these small copepods under controlled conditions.

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Seasonal variability of inorganic and organic nitrogen in the North Sea

Hydrobiologia ◽

10.1007/s10750-008-9424-y ◽

2008 ◽

Vol 610 (1) ◽

pp. 83-98 ◽

Cited By ~ 15

Author(s):

Suhaimi Suratman ◽

Tim Jickells ◽

Keith Weston ◽

Liam Fernand

Keyword(s):

North Sea ◽

Seasonal Variability ◽

Organic Nitrogen ◽

The North ◽

The North Sea ◽

Inorganic And Organic Nitrogen ◽

Inorganic And Organic

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Large-scale responses of nematode communities to chronic otter-trawl disturbance

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f08-002 ◽

2008 ◽

Vol 65 (4) ◽

pp. 723-732 ◽

Cited By ~ 11

Author(s):

Hilmar Hinz ◽

Jan G Hiddink ◽

James Forde ◽

Michel J Kaiser

Keyword(s):

Food Web ◽

North Sea ◽

Large Scale ◽

Life Cycles ◽

Irish Sea ◽

Otter Trawl ◽

Food Web Structure ◽

Nematode Communities ◽

The North ◽

The North Sea

Nematodes, because of their small size and short life cycles, are thought to be less affected by direct trawling mortality compared with the larger macrofauna. However, nematodes may still be indirectly affected by the physical disturbance of trawling through changing sediment characteristics and food web structure. We determined whether nematode communities on two muddy fishing grounds located in the North Sea and Irish Sea were affected by chronic otter-trawl disturbance and quantified these effects. Nematode abundance, production, and genus richness declined in response to trawling within both areas. Nematode biomass did not respond to trawling intensity. Genus composition was affected by trawling only in the North Sea. The responses in abundance of individual nematode genera to increasing trawling intensity were negative as well as positive. These results indicate that despite their size and fast life cycle, nematodes are affected by intensive trawling on muddy fishing grounds. The loss in secondary production from nematodes can have far-reaching consequences for the integrity of the benthic food web. As bottom trawl fisheries are expanding into ever deeper muddy habitats, the results presented here are an important step towards understanding the global ecosystem effects of bottom trawling.

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Decadal changes in the North Sea food web between 1981 and 1991 — implications for fish stock assessment

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f06-147 ◽

2006 ◽

Vol 63 (11) ◽

pp. 2586-2602 ◽

Cited By ~ 7

Author(s):

Alexander Kempf ◽

Jens Floeter ◽

Axel Temming

Keyword(s):

Food Web ◽

North Sea ◽

Fish Stock ◽

Fish Diet ◽

Data Set ◽

The North ◽

Stock Biomass ◽

Spawning Stock ◽

The North Sea ◽

The Impact

The North Sea ecosystem of the early 1980s differed substantially from that of the early 1990s. The current North Sea multispecies fisheries assessment models are parameterized by fish diet data sets that reflect both ecosystem states, as the stomachs were sampled in 1981 and 1991. In this study, multispecies virtual population analysis (MSVPA) was parameterized with either diet data set, leading to different model food webs, each representing the predator's diet selection behavior and spatiotemporal overlap with their prey in the two respective ecosystem states. The impact of these changes in predator preferences and spatiotemporal overlap on recruitment success and on stock developments could be demonstrated by using either stomach data set to estimate historic and future spawning stock biomass and recruitment trajectories. The observed changes in the food web mainly impacted the hindcasted recruitment trajectories, whereas spawning stock biomass estimates were quite robust. In the prediction runs, the differences in the survival rate of the recruits decided whether fish stocks of commercially important species (e.g., Gadus morhua, Merlangius merlangus) would recover or collapse in the near future.

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