Variation in abundance of Norwegian spring‐spawning herring (<i>Clupea harengus</i>, Clupeidae) throughout the 20th century and the influence of climatic fluctuations

Toresen, Reidar; Østvedt, Ole-Johan

doi:10.1111/j.1467-2979.2000.00022.x

Cited by 117 publications

(149 citation statements)

References 14 publications

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“…A regression of catch levels on temperature, both current and lagged values, for the period after 1974 (the low point of the catch series) did not reveal any statistically significant relationship between catch and temperature. This result is somewhat at odds with Thoresen and Østvedt (2000) who found a relationship between temperature and the spawning stock of herring, using a longer time period and a different methodology.…”

Section: Herringcontrasting

confidence: 55%

Geographical distribution of fish catches and temperature variations in the northeast Atlantic since 1945

Hannesson

2007

Marine Policy

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INTRODUCTIONThe global warming that is widely expected to occur over this century will not be confined to the atmosphere; the oceans would also get warmer. Such changes are likely to affect fish migrations and habitat, augmenting fish stocks in some places and decreasing them in others, perhaps causing stocks to be displaced permanently to new habitats. Over the next 50 years, temperatures in the Northeast Atlantic, and especially the Barents Sea, are expected to rise by 1 -3 degrees. This is expected to lead to an increase of the Northeast Arctic cod stock and to displace it in a northeasterly direction, while capelin, another important stock in this area, is expected to retreat further north and northeast. The herring stock in the Norwegian Sea is expected to be favorably affected, and mackerel is expected to migrate to a greater extent into the Norwegian Sea. As a result of a warming of the North Sea, the cod stock is expected to decline while anchovy and sardine would become more abundant. 1 Twelve-months moving average of temperatures in the 1-50 m depth range, centered in month 6, at five locations along the Norwegian coast.Temperature changes of this magnitude are not unparalleled in recent times. Figure 1 shows a 12-months moving average of temperatures at five locations along the Norwegian coast, from Lista in the far south to Ingøy in the far north. 2 The series are incomplete, and even more so than this figure shows, as we have interpolated for missing months when the gap in the data is no more than 8 consecutive months. 3 The difference between the highest and lowest average annual temperatures is 2 -3 degrees. There is little or no trend in the series; the temperatures 1 On these changes, see Stenevik and Sundby (2003). 2 These observations are taken at less than 50 meters depth.

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Section: Herringcontrasting

confidence: 55%

Geographical distribution of fish catches and temperature variations in the northeast Atlantic since 1945

Hannesson

2007

Marine Policy

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“…To find the biomass of herring ages 1 and 2 (BM herr,t ), we used the following equations N herr;age1;t Z N herr;age0;tÿ1 !expðK0:9KF herr;age0;tÿ1 Þ ð3:6aÞ N herr;age2;t Z N herr;age1;tÿ1 !expðK0:9KF herr;age1;tÿ1 Þ ð3:6bÞ BM herr;t Z W herr;age1 !N herr;age1;t C W herr;age2 !N herr;age2;t ; ð3:6cÞ where F herr,age0 and F herr,age1 are the observed fishing mortalities for ages 0 and 1, respectively, and W herr,age1 and W herr,age2 are the observed mean individual weights 1921-2003 for ages 1 and 2 (in kilogram). The fixed natural mortality at 0.9 is the same as the natural mortality for these age groups assumed in the VPA procedure (Toresen & Østvedt 2000). Using equations 3.3 and 3.4a,b and adding the effect of harvest, the predicted BM herr,t was used to predict ABM capelin,t of equation (3.2).…”

Section: ð3:5þmentioning

confidence: 99%

Food web dynamics affect Northeast Arctic cod recruitment

et al. 2006

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Proper management of ecosystems requires an understanding of both the species interactions as well as the effect of climate variation. However, a common problem is that the available time-series are of different lengths. Here, we present a general approach for studying the dynamic structure of such interactions. Specifically, we analyse the recruitment of the world's largest cod stock, the Northeast Arctic cod. Studies based on data starting in the 1970-1980s indicate that this stock is affected by temperature through a variety of pathways. However, the value of such studies is somewhat limited by the fact that they are based on a quite specific ecological and climatic situation. Recently, this stock has consisted of fairly young fish and the spawning stock has consisted of relatively few age groups. In this study, we develop a model for the effect of capelin (the cod's main prey) and herring on cod recruitment since 1973. Based on this model, we analyse data on cod, herring and temperature going back to 1921 and find that food-web effects explain a significant part of the cod recruitment variation back to around 1950.

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“…The length of the 0-group cod is closely related to the mean annual temperature of the Kola section (running north from the Kola Peninsula along 33°30'E into the Barents Sea) indicating higher growth at higher temperatures. There is also a clear connection between the temperature and the Barents Sea herring stock, based on data from the Kola section (Toresen and Østvedt 2000).…”

Section: Fisheriesmentioning

confidence: 99%

“…Research suggests that climate change can alter fish stocks in the Barents Sea by 25% in either direction, making it difficult to project whether to expect beneficial or detrimental impacts. Toresen and Østvedt (2000) suggested how a warmer climate might influence the distribution of common fish stocks. As a consequence of the warming, the seasonal ice zone will also move further north during winter.…”

Section: Fisheriesmentioning

confidence: 99%

Critical vulnerabilities of marine and sea ice–based ecosystems in the high Arctic

Johannessen

Miles

2010

Reg Environ Change

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The objectives of this paper are to summarise: (1) observed 20th-century and projected 21st-century changes in key components of the Arctic climate system and (2) probable impacts on the Arctic marine environment, with emphasis on the vulnerabilities of marine and sea ice-based ecosystems. Multi-decadal to century-scale observational data sets of surface air temperature (SAT) and sea ice indicate that the two pronounced 20th-century warming events, both amplified in the Arctic, were linked to sea-ice variability. Arctic sea-ice coverage has decreased *8% in the past quarter century, with record-and nearrecord low summer ice in observed recent years. A set of coupled atmosphere-ice-ocean global model simulations quantifies the expected changes in Arctic temperature and sea ice through the twenty-first century. Projected are polar-amplified increases in SAT and reductions in sea ice, with a predominantly ice-free Arctic Ocean in summer projected before the end of this century. A range of potential consequences of Arctic warming and a shrinking ice cover are foreseen. First, exposure of vast areas of the Arctic Ocean would greatly alter the coastal and shelf marine environment. Second, broad changes in the marine and sea ice-based ecosystem-e.g. changes in plankton due to less ice and greater inflow of melt water-could negatively impact Arctic and sub-Arctic marine biodiversity, not least the vulnerable ice-based mammals such as polar bears. Third, there would be a larger open area for potential Arctic fisheries, as well as increased offshore activities and marine transportation, including the Northern Sea Route north of Siberia. Changes in the physical environment of the Arctic Ocean are thus expected to be dramatic, and although projecting ecosystem changes several decades into twenty-first century is challenging, the impact of diminishing sea ice on Arctic marine and sea ice-based ecosystems will certainly be transformative.

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Variation in abundance of Norwegian spring‐spawning herring (Clupea harengus, Clupeidae) throughout the 20th century and the influence of climatic fluctuations

Cited by 117 publications

References 14 publications

Geographical distribution of fish catches and temperature variations in the northeast Atlantic since 1945

Geographical distribution of fish catches and temperature variations in the northeast Atlantic since 1945

Food web dynamics affect Northeast Arctic cod recruitment

Critical vulnerabilities of marine and sea ice–based ecosystems in the high Arctic

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