The combined effect of transport and temperature on distribution and growth of larvae and pelagic juveniles of Arcto-Norwegian cod

2005 ◽  
Vol 62 (7) ◽  
pp. 1375-1386 ◽  
Author(s):  
Frode Vikebø ◽  
Svein Sundby ◽  
Bjørn Ådlandsvik ◽  
Øyvind Fiksen
Keyword(s):  
Barents Sea ◽  
Field Studies ◽  
Trophic Levels ◽  
Direct Effects ◽  
Climatic Parameters ◽  
Fish Stocks ◽  
The Barents Sea ◽  
Effects Of Temperature ◽  
Pelagic Juveniles ◽  
Pelagic Juvenile

Abstract Temperature has been identified in field studies as the physical parameter most influential on growth and recruitment of Arcto-Norwegian cod. However, it has been pointed out by many authors that temperature in this context has not only direct effects on the cod, but also indirect effects through lower trophic levels. Moreover, it has been said that temperature might also be a proxy for other climatic parameters. The present paper analyses the direct quantitative effects of temperature on larval and pelagic juvenile growth from spawning in Lofoten until the 0-group fish settle in the Barents Sea. The approach taken is that of a modelling study, supported by analysis of existing data on fish stocks and climate. It is shown that transport and temperature alone can reproduce key features of the 0-group weight distribution and concentration in the Barents Sea for two consecutive years. The extent of the dispersion of the larvae and pelagic juveniles, as well as the ambient temperature they experience on their route, are shown to depend upon their depth in the water column and, to a lesser degree, the time of spawning.

scholarly journals Comparison of the biophysical and trophic characteristics of the Bering and Barents Seas

2005 ◽  
Vol 62 (7) ◽  
pp. 1245-1255 ◽  
Author(s):  
George L. Hunt ◽  
Bernard A. Megrey
Keyword(s):  
Bering Sea ◽  
Barents Sea ◽  
Single Species ◽  
Atlantic Water ◽  
Walleye Pollock ◽  
Fish Stocks ◽  
Eastern Bering Sea ◽  
The Barents Sea ◽  
Shelf Seas ◽  
Bottom Waters

Abstract The eastern Bering Sea and the Barents Sea share a number of common biophysical characteristics. For example, both are seasonally ice-covered, high-latitude, shelf seas, dependent on advection for heat and for replenishment of nutrients on their shelves, and with ecosystems dominated by a single species of gadoid fish. At the same time, they differ in important respects. In the Barents Sea, advection of Atlantic Water is important for zooplankton vital to the Barents Sea productivity. Advection of zooplankton is not as important for the ecosystems of the southeastern Bering Sea, where high levels of diatom production can support production of small, neritic zooplankton. In the Barents Sea, cod are the dominant gadoid, and juvenile and older fish depend on capelin and other forage fish to repackage the energy available in copepods. In contrast, the dominant fish in the eastern Bering Sea is the walleye pollock, juveniles and adults of which consume zooplankton directly. The southeastern Bering Sea supports considerably larger fish stocks than the Barents. In part, this may reflect the greater depth of much of the Barents Sea compared with the shallow shelf of the southeastern Bering. However, walleye pollock is estimated to occupy a trophic level of 3.3 as compared to 4.3 for Barents Sea cod. This difference alone could have a major impact on the abilities of these seas to support a large biomass of gadoids. In both seas, climate-forced variability in advection and sea-ice cover can potentially have major effects on the productivity of these Subarctic seas. In the Bering Sea, the size and location of pools of cold bottom waters on the shelf may influence the likelihood of predation of juvenile pollock.

The Barents Sea Loophole Agreement: A "Coastal State" Solution to a Straddling Stock Problem

1999 ◽  
Vol 14 (4) ◽  
pp. 467-490 ◽  
Author(s):  
Robin R Churchill
Keyword(s):  
Barents Sea ◽  
State Solution ◽  
Fishing Rights ◽  
Fish Stocks ◽  
Coastal State ◽  
The Barents Sea ◽  
Unregulated Fishing ◽  
Conservation And Management ◽  
High Seas

AbstractIn May 1999 Iceland, Norway and Russia signed an agreement (the "Loophole Agreement") designed to resolve a six-year dispute over unregulated fishing by Icelandic vessels for straddling stocks in an enclave ("the Loophole") of high seas in the central Barents Sea. The Agreement, which gives Iceland fishing rights in the Norwegian and Russian EEZs in return for ceasing fishing in the Loophole, is an example of direct co-operation between coastal and high seas fishing states over the management of straddling fish stocks on the high seas which the 1995 UN Agreement on the Conservation and Management of Straddling Fish Stocks envisages as a possible alternative to management through a regional fisheries organisation. The article explains why the parties have chosen this model rather than utilising the existing regional fisheries organisation or establishing a new regional fisheries arrangement; and compares the Loophole Agreement with arrangements for some other high seas enclaves.

scholarly journals Integrating spatial and temporal mortality from herring on capelin larvae: a study in the Barents Sea

2009 ◽  
Vol 66 (10) ◽  
pp. 2183-2194 ◽  
Author(s):  
O. P. Pedersen ◽  
T. Pedersen ◽  
K. S. Tande ◽  
D. Slagstad
Keyword(s):  
Experimental Data ◽  
Mortality Rate ◽  
Barents Sea ◽  
Field Surveys ◽  
Fish Stocks ◽  
The Barents Sea ◽  
Spatio Temporal ◽  
The Impact ◽  
Important Fish ◽  
Temporal Overlap

Abstract Pedersen, O. P., Pedersen, T., Tande, K. S., and Slagstad, D. 2009. Integrating spatial and temporal mortality from herring on capelin larvae: a study in the Barents Sea. – ICES Journal of Marine Science, 66: 2183–2194. Barents Sea herring and capelin are commercially very important fish stocks. We investigate the spatial and temporal mortality rate of capelin larvae in 2001 as a function of herring predation. Our methods are based on Lagrangian modelling, field surveys, and experimental data. The impact of juvenile herring predation on capelin recruitment is corroborated, in particular the importance of the integrated spatio-temporal overlap between the two stocks. Capelin larvae were reduced to 20–50% in two weeks in accordance with different simulation scenarios. Hamre advanced a hypothesis in 1994 that juvenile herring are important predators of capelin larvae and a main cause of poor capelin recruitment in years when herring are very abundant in the Barents Sea. This hypothesis is supported through the results of this work.

scholarly journals Skilful prediction of cod stocks in the North and Barents Sea a decade in advance

2021 ◽  
Author(s):  
Vimal Koul ◽  
Camilla Sguotti ◽  
Marius Årthun ◽  
Sebastian Brune ◽  
André Düsterhus ◽  
...  
Keyword(s):  
Barents Sea ◽  
Statistical Prediction ◽  
Fish Stock ◽  
Fish Stocks ◽  
Ocean Climate ◽  
The North ◽  
Stock Biomass ◽  
The North Sea ◽  
Linear Effects ◽  
Effects Of Temperature

Abstract Reliable information about the future state of the ocean and fish stocks is necessary for informed decision-making by fisheries scientists, managers and the industry. However, multiyear regional ocean climate and fish stock predictions have until now had low forecast skill. Here, we provide skillful forecasts of the biomass of cod stocks in the North and Barents Seas a decade in advance. We develop a unified dynamical-statistical prediction system wherein statistical models link future total stock biomass to dynamical predictions of sea surface temperature, while also considering different fishing mortalities. We evaluate non-linear effects of temperature and fishing on cod biomass, and provide evidence of climate-derived predictability in cod stocks. We forecast the continuation of unfavorable oceanic conditions for the North Sea cod for the coming decade which would inhibit its recovery at present fishing levels, and a decrease in Northeast Arctic cod stock compared to the recent high levels.

Maritime Delimitation in the Arctic: Implications for Fisheries Jurisdiction and Cooperation in the Barents Sea

2015 ◽  
Vol 30 (1) ◽  
pp. 120-147
Author(s):  
Irene Dahl
Keyword(s):  
Barents Sea ◽  
The Arctic ◽  
Fish Stocks ◽  
The Barents Sea ◽  
Conservation And Management

After 40 years of negotiations, Norway and Russia entered into the Barents Sea Treaty in 2010. The treaty fixes the delimitation line in the Barents Sea. During this period the parties succeeded in developing a body for cooperation on conservation and management of the shared/straddling fish stocks: the joint Norwegian-Russian Fisheries Commission. This article examines the effect of the treaty on fisheries jurisdiction and future fisheries cooperation between Norway and Russia.

Joint investigations on fish stocks in the Barents Sea

Polar Record ◽  
1977 ◽  
Vol 18 (117) ◽  
pp. 618-619
Author(s):  
Odd M. Smedstad
Keyword(s):  
Barents Sea ◽  
Fish Stocks ◽  
The Barents Sea

scholarly journals Sea ice, temperature, and prey effects on annual variations in mean lengths of a key Arctic fish, Boreogadus saida, in the Barents Sea

2020 ◽  
Vol 77 (5) ◽  
pp. 1796-1805
Author(s):  
Nicolas Dupont ◽  
Joël M Durant ◽  
Øystein Langangen ◽  
Harald Gjøsæter ◽  
Leif Christian Stige
Keyword(s):  
Sea Ice ◽  
Barents Sea ◽  
Trophic Levels ◽  
The Arctic ◽  
Polar Cod ◽  
Boreogadus Saida ◽  
Sea Ice Concentration ◽  
The Barents Sea ◽  
Ice Concentration ◽  
High Length

Abstract Oceanographic conditions in the Arctic are changing, with sea ice cover decreasing and sea temperatures increasing. Our understanding of the effects on marine populations in the area is, however, limited. Here, we focus on the Barents Sea stock of polar cod (Boreogadus saida). Polar cod is a key fish species for the transfer of energy from zooplankton to higher trophic levels in the Arctic food web. We analyse the relationships between 30-year data series on the length-at-age of polar cod cohorts (ages 0–4) and sea surface temperature, sea ice concentration, prey biomasses, predator indices, and length-at-age the previous year using multiple linear regression. Results for several ages showed that high length-at-age is significantly associated with low sea ice concentration and high length-at-age the previous year. Only length-at-age for age 1 shows a positive significant relationship with prey biomass. Our results suggest that retreating sea ice has positive effects on the growth of polar cod in the Barents Sea despite previous observations of a stagnating stock biomass and decreasing stock abundance. Our results contribute to identifying mechanisms by which climate variability affects the polar cod population, with implications for our understanding of how future climate change may affect Arctic ecosystems.

scholarly journals Historical variations in the year-class strength of beaked redfish (Sebastes mentella) in the Barents Sea

2012 ◽  
Vol 69 (4) ◽  
pp. 547-552 ◽  
Author(s):  
B. Planque ◽  
E. Johannesen ◽  
K. V. Drevetnyak ◽  
K. H. Nedreaas
Keyword(s):  
Barents Sea ◽  
Statistical Modelling ◽  
Fish Stocks ◽  
Recruitment Failure ◽  
The Barents Sea ◽  
Class Strength ◽  
Sebastes Mentella ◽  
High Recruitment ◽  
Scientific Survey ◽  
Modelling Approach

Abstract Planque, B., Johannesen, E., Drevetnyak, K. V., and Nedreaas, K. H. 2012. Historical variations in the year-class strength of beaked redfish (Sebastes mentella) in the Barents Sea. – ICES Journal of Marine Science, 69: 547–552. The present work provides the first quantitative estimate of the historical fluctuations in the year-class strength of beaked redfish in the Barents Sea. The year-class strength index is based on scientific survey data collected by Norway and Russia during the past three decades. It is defined as the effective number of 0-group fish that will eventually enter the fishery. Uncertainties in the year-class strength indices are estimated using a statistical modelling approach, which accounts for observation errors. The reconstructed series indicate clear periods of high recruitment (late 1980s–early 1990s) and 8 years of near complete recruitment failure (1996–2003). The apparent recovery in recent years is highly uncertain and needs to be confirmed by future observations. The modelling approach developed here can be applied to other fish stocks for which catch-at-age data are available from several surveys.

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