Congruent shifts in sand eel abundance in western and eastern North Atlantic ecosystems

Sherman, Kenneth; Jones, Christian M.; Sullivan, Laurie; Smith, W.; Berrien, Peter L.; Ejsymont, L.

doi:10.1038/291486a0

Cited by 82 publications

(35 citation statements)

References 9 publications

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“…I NAO has been shown to influence oceanic inflow, primary production and zooplankton communities in the North Sea (Fromentin & Planque 1996, Planque & Fromentin 1996, Heyen et al 1998, and therefore one would expect it also to affect the feeding conditions experienced by planktivores such as sandeels. Sherman et al (1981) attributed a rising abundance of sandeels on the opposite (northwest) side of the Atlantic to the over-exploitation of herring and mackerel (both sandeel predators), implying that top-down effects were dominant within the system. In the North Sea, herring are important predators of sandeel larvae (Hardy 1924), but tend to occupy more northerly areas during warm years (Corten 2001), which suggests that they were not responsible for the effects we detected, since the negative influence of warm conditions was most noticeable in the southern part of the North Sea (Region 1).…”

Section: Discussionmentioning

confidence: 99%

Sandeel recruitment in the North Sea: demographic, climatic and trophic effects

Arnott¹,

Ruxton²

2002

Mar. Ecol. Prog. Ser.

132

142

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The lesser sandeel Ammodytes marinus, which is one of the most abundant fish in the North Sea, has highly variable recruitment dynamics. We evaluate potential associations between their recruitment and some key biological and physical factors. Population data were analysed at the North Sea scale (years 1983 to 1999) and at the regional scale (southwestern section and northeastern section; years 1984 to 1996/7). Relationships between recruitment and spawning stock biomass were weak, but Age-1 sandeels (non-spawners) were related negatively with recruitment, implying that demographic effects are important. A negative relationship was detected between recruitment and the winter index of the North Atlantic Oscillation, which affects sea temperatures during the egg and larval period. Warmer sea temperatures correlated with poorer than average recruitment. This effect was most pronounced in the southwestern part of the North Sea, which is near the southern limit of the species' distribution. There was a positive association between recruitment and Calanus copepod (Stages V and VI) abundance around the time of larval hatching, suggesting that the availability of this prey species is important for young sandeel survival. Our findings suggest that climate change may impact upon sandeel populations in the North Sea.

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Section: Discussionmentioning

confidence: 99%

Sandeel recruitment in the North Sea: demographic, climatic and trophic effects

Arnott¹,

Ruxton²

2002

Mar. Ecol. Prog. Ser.

132

142

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“…The level of competition between cetaceans and fisheries can also change with natural or anthropogenic shifts in fish stocks. Since the 1960s, there have been several shifts in dominance in Northeast Shelf pelagic fish stocks between herring (and mackerel) and sand lance (Sherman et al, 1981(Sherman et al, , 1988Sherman, 1986;Sissenwine, 1986;Fogarty et al, 1991). Cetacean predation on small pelagic fishes has also shifted in parallel, with concomitant changes in cetacean distribution patterns (Payne et al ., 1986Schilling et al, 1992;Kenney et al, 1996).…”

Section: Discussionmentioning

confidence: 99%

Estimates of Prey Consumption and Trophic Impacts of Cetaceans in the USA Northeast Continental Shelf Ecosystem

Kenney¹,

Scott²,

Thompson³

et al. 1997

J. Northw. Atl. Fish. Sci.

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Whales, dolphins and porpoises are significant consumers of prey resources in the USA Northeast Shelf marine ecosystem to a far greater extent than was realized two decades ago. Seasonal estimates of the consumption of finfish, squid and zooplankton by cetaceans were calculated for four regions of the Northeast Shelf system defined as Gulf of Maine, Georges Bank, Southern New England and Mid-Atlantic Bight. Estimates were based on seasonal cetacean abundance using standard mammalian metabolic models scaled as appropriate for assimilation, activity and migratory fasting. Estimates were made of mean body mass and proportion of the diet comprised of each of the three main prey types. Cetaceans of the Northeast Shelf were found to consume nearly 1.9 million tons annually, including about 1.3 million tons of fish, 337 000 tons of squid and 244 000 tons of zooplankton. Their predation on fish and squid exceeded tonnages harvested in the commercial fishing industry. Consumption estimates of fish dominated in most regions and seasons, primarily because of the widespread distribution and high relative abundance of large piscivorous fin whales, and secondarily due to the presence of humpback and minke whales and some of the smaller odontocetes. Zooplankton consumption, principally by right and sei whales and secondarily by other mysticetes, was significant in some seasons in the Gulf of Maine and Georges Bank regions. An assemblage which included a variety of teuthivorous odontocete species inhabiting the shelf break vicinity consumed substantial quantities of squid in all regions except the Gulf of Maine. Using a simple five-level trophic model and 10% estimated trophic transfer efficiency, the estimates implied that a significant fraction of the total net primary production, ranging from 11.7% in the Mid-Atlantic Bight to 20.4% in the Gulf of Maine, was required to the support cetacean apex predation.

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“…Overfishing of large fishes can lead to increases in the abundances of smaller fishes. This is often evident when fisheries target large predators that can include pelagic species (Sherman et al 1981), demersal species (Bundy 2005) or large marine mammals (Springer et al 2003, Estes et al 2006. Because it is the indirect relationships in food webs that are often pervasive, complexity often overrides straightforward rebounds of prey populations once predators are removed (Yodzis 2001).…”

Section: Trophic Dynamics and Community Roles Of Seabirdsmentioning

confidence: 99%