scholarly journals Benthic biomass size spectra in shelf and deep-sea sediments

2014 ◽  
Vol 11 (1) ◽  
pp. 901-942 ◽  
Author(s):  
B. A. Kelly-Gerreyn ◽  
A. P. Martin ◽  
B. J. Bett ◽  
T. R. Anderson ◽  
J. I. Kaariainen ◽  
...  
Keyword(s):  
Body Size ◽  
Atlantic Water ◽  
Scaling Exponent ◽  
Size Spectra ◽  
Size Classes ◽  
North East ◽  
The North ◽  
The North Sea ◽  
Wet Weight ◽  
Biomass Spectra

Abstract. The biomass distributions of marine benthic organisms (meio- to macro-fauna, 1 μg–32 mg wet weight) across three contrasting sites were investigated to test the hypothesis that allometry can consistently explain observed trends in biomass spectra. Biomass (and abundance) size spectra were determined from observations made at the Faroe–Shetland Channel in the north-east Atlantic (water depth 1600 m), the Fladen Ground in the North Sea (150 m), and the hypoxic Oman Margin (500 m) in the Arabian Sea. Observed biomass increased with body size as a power law at FG (scaling exponent, b = 0.16) and FSC (b = 0.32), but less convincingly at OM (b = 0.12 but not significantly different from 0). A simple model was constructed to represent the same 16 metazoan size classes used for the observed spectra, all reliant on a common detrital food pool, and allowing the three key processes of ingestion, respiration and mortality to scale with body size. A micro-genetic algorithm was used to fit the model to observations at the sites. The model accurately reproduces the observed scaling without recourse to including the effects of local influences such as hypoxia. Our results suggest that the size-scaling of mortality and ingestion are dominant factors determining the distribution of biomass across the meio- to macrofaunal size range in contrasting marine sediment communities. Both the observations and the model results are broadly in agreement with the "Metabolic Theory of Ecology" in predicting a quarter power scaling of biomass across geometric body size classes.

scholarly journals Benthic biomass size spectra in shelf and deep-sea sediments

2014 ◽  
Vol 11 (22) ◽  
pp. 6401-6416 ◽  
Author(s):  
B. A. Kelly-Gerreyn ◽  
A. P. Martin ◽  
B. J. Bett ◽  
T. R. Anderson ◽  
J. I. Kaariainen ◽  
...  
Keyword(s):  
Body Size ◽  
Atlantic Water ◽  
Scaling Exponent ◽  
Metabolic Theory ◽  
Size Spectra ◽  
Size Classes ◽  
The North ◽  
The North Sea ◽  
Wet Weight ◽  
Biomass Spectra

Abstract. The biomass distributions of marine benthic metazoans (meio- to macro-fauna, 1 μg–32 mg wet weight) across three contrasting sites were investigated to test the hypothesis that allometry can consistently explain observed trends in biomass spectra. Biomass (and abundance) size spectra were determined from observations made at the Faroe–Shetland Channel (FSC) in the Northeast Atlantic (water depth 1600 m), the Fladen Ground (FG) in the North Sea (150 m), and the hypoxic Oman Margin (OM) in the Arabian Sea (500 m). Observed biomass increased with body size as a power law at FG (scaling exponent, b = 0.16) and FSC (b = 0.32), but less convincingly at OM (b = 0.12 but not significantly different from 0). A simple model was constructed to represent the same 16 metazoan size classes used for the observed spectra, all reliant on a common detrital food pool, and allowing the three key processes of ingestion, respiration and mortality to scale with body size. A micro-genetic algorithm was used to fit the model to observations at the sites. The model accurately reproduces the observed scaling without needing to include the effects of local influences such as hypoxia. Our results suggest that the size-scaling of mortality and ingestion are dominant factors determining the distribution of biomass across the meio- to macrofaunal size range in contrasting marine sediment communities. Both the observations and the model results are broadly in agreement with the "metabolic theory of ecology" in predicting a quarter power scaling of biomass across geometric body size classes.

Controls on benthic biomass size spectra in shelf and deep-sea sediments – a modelling study

2011 ◽  
Vol 8 (4) ◽  
pp. 8189-8240 ◽  
Author(s):  
B. A. Kelly-Gerreyn ◽  
T. R. Anderson ◽  
B. J. Bett ◽  
A. P. Martin ◽  
J. I. Kaariainen
Keyword(s):  
Body Size ◽  
The Body ◽  
General Observation ◽  
Size Spectra ◽  
Size Classes ◽  
North East ◽  
The North ◽  
The North Sea ◽  
Wet Weight ◽  
Biomass Spectra

Abstract. Factors controlling biomass distributions in marine benthic organisms (meio- to macro-fauna, 1 μg–32 mg wet weight) were investigated through observations and allometric modelling. Biomass (and abundance) size spectra were measured at three locations: the Faroe-Shetland Channel in the north-east Atlantic (FSC, water depth 1600 m, September 2000); the Fladen Ground in the North Sea (FG, 150 m, September 2000); and the hypoxic Oman Margin (OM, 500 m, September 2002) in the Arabian Sea. Biomass increased with body size through a power law at FG (allometric exponent, b = 0.16) and at FSC (b = 0.32), but less convincingly at OM (b was not significantly different from −1/4 or 0). Our results question the assumption that metazoan biomass spectra are bimodal in marine sediments. The model incorporated 16 metazoan size classes, as derived from the observed spectra, all reliant on a common detrital food pool. All physiological (ingestion, mortality, assimilation and respiration) parameters scaled to body size following optimisation to the data at each site, the resulting values being consistent within expectations from the literature. For all sites, body size related changes in mortality played the greatest role in determining the trend of the biomass size spectra. The body size trend in the respiration rate was most sensitive to allometry in both mortality and ingestion, and the trend in body size spectra of the production: biomass ratio was explained by the allometry in ingestion. Our results suggest that size-scaling mortality and ingestion are important factors determining the distribution of biomass across the meiofauna to macrofauna size range in marine sedimentary communities, in agreement with the general observation that biomass tends to accumulates in larger rather than smaller size classes in these environments.

scholarly journals Running the gauntlet: the predation environment of small fish in the northern Gulf of St Lawrence, Canada

2005 ◽  
Vol 62 (3) ◽  
pp. 412-416 ◽  
Author(s):  
Daniel E. Duplisea
Keyword(s):  
Body Size ◽  
North Sea ◽  
Prey Size ◽  
Small Fish ◽  
Size Spectra ◽  
Predator Prey ◽  
The North ◽  
Prefer Prey ◽  
Seal Population ◽  
The North Sea

Abstract Predation size spectra were constructed for the northern Gulf of St Lawrence, covering prey size ranges that include pre-recruit cod. Predation by fish and harp seals was modelled with a log-normally distributed predator–prey size ratio along with a relationship between predator body size and the energy required. Fish concentrate predation on prey of weight 0.5–2 g, whereas harp seals prefer prey of 60–125 g. It is speculated that predation caused by harp seals on pre-recruits could be a major factor limiting cod recruitment in the system. The northern Gulf of St Lawrence is a cold boreal system with a large predatory seal population, and cod recruit older than elsewhere. Therefore, cod recruitment may be more strongly affected by predation in the northern Gulf of St Lawrence than in warmer systems such as the North Sea, where recruitment is strongly influenced by temperature.

scholarly journals Steeper biomass spectra of demersal fish communities after trawler exclusion in Sicily

2009 ◽  
Vol 66 (1) ◽  
pp. 195-202 ◽  
Author(s):  
Christopher J. Sweeting ◽  
Fabio Badalamenti ◽  
Giovanni D'Anna ◽  
Carlo Pipitone ◽  
N. V. C. Polunin
Keyword(s):  
Fish Communities ◽  
Demersal Fish ◽  
Small Fish ◽  
Size Spectra ◽  
Seasonal Differences ◽  
Fish Size ◽  
Size Classes ◽  
The North ◽  
Spawning Behaviour ◽  
Biomass Spectra

Abstract Sweeting, C. J., Badalamenti, F., D'Anna, G., Pipitone, C., and Polunin, N. V. C. 2009. Steeper biomass spectra of demersal fish communities after trawler exclusion in Sicily. – ICES Journal of Marine Science, 66: 195–202. The effects of trawling on Mediterranean demersal fish communities were assessed by comparing them with the normalized biomass spectra among three gulfs on the north Sicilian coast, one of which had been subject to 15 years of trawler exclusion. Comparisons were conducted across seasons and among depth strata. Biomass-spectra slopes were significantly steeper in the gulf that was closed to trawling than in the unprotected gulfs. This was attributed to the exclusion of trawlers, which lacked catch-size selectivity, and to the continued fishing by artisanal gears that are more size selective. The biomass of all size classes was higher in the protected gulf than in unprotected areas, and increases were greatest in smaller size classes. Community mean individual fish mass was similar among all areas with a wider range of body masses present in the trawl exclusion area, compensating for the greater abundance of small fish. Size-spectra slopes were generally shallower and midpoint heights lower with increasing depth and were greater in autumn than spring; the effect of these seasonal and depth factors was as great as that of protection. Depth patterns are explainable by bathymetric trends in within- and among-species fish size. Seasonal differences were attributed to variation in spawning behaviour and fishery recruitment, with seasonal differences being greater in unprotected locations as a result of recruitment overfishing.

Exceptional influx of oceanic species into the North Sea late 1997

1999 ◽  
Vol 79 (4) ◽  
pp. 737-739 ◽  
Author(s):  
M. Edwards ◽  
A.W.G. John ◽  
H.G. Hunt ◽  
J.A. Lindley
Keyword(s):  
North Sea ◽  
Indicator Species ◽  
Climatic Conditions ◽  
Historical Evidence ◽  
East Atlantic ◽  
North East ◽  
The North ◽  
The North Sea ◽  
Oceanic Species

Continuous Plankton Recorder records from the North Sea and north-east Atlantic from September 1997 to March 1998 indicate an exceptional influx of oceanic indicator species into the North Sea. These inflow events, according to historical evidence, have only occurred sporadically during this century. This exceptional inflow and previous inflow events are discussed in relation to their similarity in terms of their physical and climatic conditions.

scholarly journals Ovary resorption in the Norway lobster (Nephrops norvegicus) and its possible causes with special reference to sperm storage

2020 ◽  
Vol 74 (1) ◽  
Author(s):  
Carola Becker ◽  
Jaimie T. A. Dick ◽  
E. Mánus Cunningham ◽  
Mathieu Lundy ◽  
Ewen Bell ◽  
...  
Keyword(s):  
North Sea ◽  
Demographic Data ◽  
Irish Sea ◽  
Natural Phenomenon ◽  
Nephrops Norvegicus ◽  
North East ◽  
The North ◽  
Norway Lobster ◽  
The North Sea ◽  
Reproductive Cycles

Abstract The Norway lobster, Nephrops norvegicus, is an important fisheries species in the North-East Atlantic area. In some circumstances, mature females of Nephrops norvegicus can resorb their ovary rather than completing spawning, but the implications of this phenomenon to reproductive biology and fisheries sustainability are not known. To understand after effects of ovary resorption, we studied long-term demographic data sets (1994–2017) collected from the western Irish Sea and the North Sea. Our considerations focused on potential correlations among the frequency of resorption, female insemination, and body size of resorbing females. Resorption was continuously rare in the western Irish Sea (less than 1%); whereas much higher rates with considerable year-to-year variation were observed in the North Sea (mean 9%). Resorption started in autumn after the spawning season (summer) had passed. The frequency stayed high throughout winter and declined again in spring. As sperm limitation can occur in male-biased fisheries, we expected a lack of insemination could be responsible for resorption, but affected females were indeed inseminated. Resorbing females were significantly larger than other sexually mature females in the North Sea, but the opposite trend was observed in the western Irish Sea. It is therefore possible that other, environmental factors or seasonal shifts, may trigger females to resorb their ovaries instead of spawning. Resorption may as well represent a natural phenomenon allowing flexibility in the periodicity of growth and reproduction. In this sense, observations of annual versus biennial reproductive cycles in different regions may be closely linked to the phenomenon of ovary resorption.

Archipelagos and islands

2011 ◽  
Author(s):  
Robert Van de Noort
Keyword(s):  
North Sea ◽  
Coastal Wetland ◽  
Sand Dunes ◽  
Great Distance ◽  
North East ◽  
The North ◽  
Island Archaeology ◽  
The North Sea ◽  
Shallow Soils ◽  
Blackwater Estuary

The North Sea is not renowned for its islands, and much of the modern land–sea interface is sharp, especially along the coasts of Jutland, North and South Holland and much of England. Nevertheless, the North Sea does contain a surprisingly large number of islands and archipelagos, which can be presented with reference to a clear north–south divide. In the northern half of the North Sea, most islands are of hard rock with shallow soils, and their islandness is the result of ongoing glacio-isostatic uplift of previously drowned lands and sea-level rise. With the exception of the Shetland and Orkney archipelagos, few of these islands are found at a great distance from the mainland, and the majority of the countless islands, islets, and rock outcrops off the North Sea coasts of Norway, Sweden, Scotland, and north-east England can be found within a few miles of the mainland. In the southern half of the North Sea, the islands are mainly made up of sand and clay and, in their history if not today, were frequently sandbanks formed by the sea utilizing both marine and riverine sediments. Most of the islands of the Wadden Sea in Denmark, Germany, and Holland are sandbanks elevated by aeolian-formed sand dunes. Further south, the core of the large islands of Zeeland is principally formed of riverine sands and marine clays intercalated with peat, reflecting coastal wetland conditions at various times in the Post-glacial and Holocene (Vos and Van Heeringen 1997). As with Zeeland, the islands on the English side of the North Sea, such as Mersey Island in the Blackwater estuary and Foulness Island in Essex, have now been incorporated into the mainland. Only a few islands cannot be so simply classified:Helgoland in the German Bight, a Sherwood Sandstone stack of Triassic date, is the best known example. Island archaeology, as we have seen (chapter 2), has for many decades approached islands as environments that were relatively isolated from the wider world.

Stomach contents of northern bottlenose whales Hyperoodon ampullatus stranded in the North Sea

2001 ◽  
Vol 81 (1) ◽  
pp. 143-150 ◽  
Author(s):  
M.B. Santos ◽  
G.J. Pierce ◽  
C. Smeenk ◽  
M.J. Addink ◽  
C.C. Kinze ◽  
...  
Keyword(s):  
The Netherlands ◽  
Stomach Contents ◽  
Important Species ◽  
North East ◽  
The North ◽  
Northern Latitudes ◽  
The North Sea ◽  
Fish Remains ◽  
Northern Bottlenose Whales ◽  
Hyperoodon Ampullatus

This paper presents information on the stomach contents of four northern bottlenose whales Hyperoodon ampullatus (Odontoceti: Ziphiidae) from the north-east Atlantic, an area for which there are few recent data on the feeding ecology of this species. Two of these whales were relatively recent strandings, a female stranded in August 1993 at Hargen (the Netherlands) and a male stranded in February 1997 on the island of Tåsinge (Denmark). Stomach content samples were also examined from a juvenile male stranded in November 1885 at Dunbar (Scotland) and a female stranded in August 1956 on the island of Texel (the Netherlands).  Food remains from the four samples consisted almost entirely of cephalopod beaks. Some fish remains were also found in the stomach of the Hargen and Tåsinge whales, and the latter also had crustacean remains in the stomach. The cephalopod prey consisted mainly of oceanic cephalopods: Gonatus sp. (probably G. fabricii, Cephalopoda: Teuthoidea), Taoniuspavo and Histioteuthis sp. for the Dunbar whale; Gonatus and Teuthowenia megalops for the Texel whale; Gonatus for the Hargen whale and Gonatus, T. megalops and Taonius pavo for the Tåsinge whale. Other prey species found in the Tåsinge specimen included the squid Histioteuthis reversa, H. arcturi, and the octopods Vampiroteuthis infernalis and Vitreledonella richardi. Based on the size of the lower beaks, the squid eaten included juvenile and mature individuals of the most important species (Gonatus and Teuthowenia megalops). The fish remains consisted of vertebrae of Gadidae and fish eye lenses (Hargen whale) and two Trisopterus otoliths (Tåsinge whale).  The results from this study are in agreement with those of previous authors in that cephalopods in general, and G. fabricii in particular, are the main prey of the northern bottlenose whale and other toothed whales in northern latitudes.

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