scholarly journals Effect of hatching date, vertical distribution, and interannual variation in physical forcing on northward displacement and temperature conditions of Norwegian spring-spawning herring larvae

2010 ◽  
Vol 67 (9) ◽  
pp. 1948-1956 ◽  
Author(s):  
Frode B. Vikebø ◽  
Åse Husebø ◽  
Aril Slotte ◽  
Erling Kåre Stenevik ◽  
Vidar S. Lien
Keyword(s):  
Vertical Distribution ◽  
Ambient Temperature ◽  
Interannual Variation ◽  
Barents Sea ◽  
Clupea Harengus ◽  
Coastal Current ◽  
Hatching Date ◽  
Physical Forcing ◽  
Larval Drift ◽  
Temperature Conditions

Abstract Vikebø, F. B., Husebø, Å., Slotte, A., Stenevik, E. K., and Lien, V. S. 2010. Effect of hatching date, vertical distribution, and interannual variation in physical forcing on northward displacement and temperature conditions of Norwegian spring-spawning herring larvae. – ICES Journal of Marine Science, 67: 1948–1956. Early hatching has been shown to be associated with increased survival of Norwegian spring-spawning herring (Clupea harengus) larvae. We investigated whether the process behind this association is related to larval drift and ambient temperature. A three-dimensional hydrodynamic model was used to simulate the effect of hatching date on northward displacement and temperature conditions of larvae from spawning grounds off western Norway for 1989–2008. The simulations revealed that the displacement during a period of 60 d was greatest if the larvae hatched early in the season and if they were located near the surface. The relationship between drift speed and ambient temperature was significantly negative, but less so later in the season, because the coastal current became progressively warmer. Results from the simulated interannual variations in larval drift compared with the observed survival suggest that a rapid northward displacement to the main nursery area in the Barents Sea is more important for larval survival than ambient temperature. The significant effect of northward displacement on survival could be explained by reduced overlap with predators and/or higher prey densities, but the causal processes involved remain to be investigated.

scholarly journals Growth of juvenile Norwegian spring-spawning herring in relation to latitudinal and interannual differences in temperature and fish density in their coastal and fjord nursery areas

2007 ◽  
Vol 64 (6) ◽  
pp. 1161-1172 ◽  
Author(s):  
Åse Husebø ◽  
Aril Slotte ◽  
Erling Kåre Stenevik
Keyword(s):  
Barents Sea ◽  
Negative Relationship ◽  
Clupea Harengus ◽  
Fish Density ◽  
Coastal Current ◽  
Nursery Areas ◽  
Wide Range ◽  
Competition For Food ◽  
Variable Recruitment ◽  
The Relationship

Abstract Husebø, Å., Slotte, A., and Stenevik, E. K. 2007. Growth of juvenile Norwegian spring-spawning herring in relation to latitudinal and interannual differences in temperature and fish density in their coastal and fjord nursery areas. – ICES Journal of Marine Science, 64: 1161–1172. Norwegian spring-spawning herring (Clupea harengus) spawn in February and March along the Norwegian coast from 58°N to 69°N. The larvae are transported north with the coastal current, and in autumn, the main part of the 0-group is found in the Barents Sea, and a smaller and variable fraction ends up in coastal and fjord nursery areas that experience a wide range of environmental conditions and fish densities. Based on data from herring 0–2 years old collected from 1970 to 2004, there is a positive relationship between temperature and the growth of this coastal component, in terms of length, weight, condition factor, and annual otolith increment width, and a negative relationship between acoustic abundance and the same growth indices. In general, juvenile growth decreased northwards along the coast concurrently with decreasing summer and autumn temperatures and increasing acoustic abundance. It seems, therefore, that there may be interference in the relationship between juvenile herring growth and temperature, attributable to variable recruitment, currents, larval drift, and advection into the fjords, causing latitudinal and interannual differences in fish density, and hence variable competition for food.

scholarly journals Drift Indices Confirm That Rapid Larval Displacement Is Essential for Recruitment Success in High-Latitude Oceans

2021 ◽  
Vol 8 ◽  
Author(s):  
Maik Tiedemann ◽  
Aril Slotte ◽  
Richard D. M. Nash ◽  
Erling K. Stenevik ◽  
Olav S. Kjesbu
Keyword(s):  
High Latitude ◽  
Barents Sea ◽  
Clupea Harengus ◽  
Larval Transport ◽  
Short Term ◽  
Larval Drift ◽  
Pelagic Fishes ◽  
Recruitment Success ◽  
Drift Model ◽  
The Relationship

Larval drift is a key process for successful fish recruitment. We used Norwegian spring-spawning herring (Clupea harengus) as model species to investigate the relationship between larval drift and recruitment. Larval drift indices were derived from simulations based on survey observations between 1993 and 2016. We show that forward simulated larval drift indices have an important positive relation to recruitment success. The relationship demonstrates elevated recruitment when larvae relocate rapidly northwards toward the Barents Sea. Negative or low larval drift indices coincide with only weak recruitment emphasizing limited survival in years with enhanced larval retention. Hence, with this work we combine drift model outcomes refined with survey data indicating that more extensive larval drift is an important component in population dynamics for high-latitude small pelagic fishes. However, larval displacement alone represents only one among many controlling factors but may offer possible predictions of the probability of higher or lower recruitment in the short term. The applicability of the drift indices is adaptable in all world oceans and all marine organisms that occupy planktonic life stages exposed to dynamic ocean currents. The study demonstrates how larval drift indices help to identify larval transport or retention to be crucial for population replenishment.

Design and Fabrication of a Magnetocaloric Microcooler

2005 ◽  
Author(s):  
Sangchae Kim ◽  
Bharath Bethala ◽  
Simone Ghirlanda ◽  
Senthil N. Sambandam ◽  
Shekhar Bhansali
Keyword(s):  
Magnetic Field ◽  
Ambient Temperature ◽  
Temperature Change ◽  
Entropy Change ◽  
Temperature Sensors ◽  
Experimental Results ◽  
Maximum Temperature ◽  
Alternative Technology ◽  
Temperature Conditions ◽  
Si Wafer

Magnetocaloric refrigeration is increasingly being explored as an alternative technology for cooling. This paper presents the design and fabrication of a micromachined magnetocaloric cooler. The cooler consists of fluidic microchannels (in a Si wafer), diffused temperature sensors, and a Gd5(Si2Ge2) magnetocaloric refrigeration element. A magnetic field of 1.5 T is applied using an electromagnet to change the entropy of the magnetocaloric element for different ambient temperature conditions ranging from 258 K to 280 K, and the results are discussed. The tests show a maximum temperature change of 7 K on the magnetocaloric element at 258 K. The experimental results co-relate well with the entropy change of the material.

scholarly journals Characteristics of the Norwegian Coastal Current during Years with High Recruitment of Norwegian Spring Spawning Herring (Clupea harengus L.)

PLoS ONE ◽  
2015 ◽  
Vol 10 (12) ◽  
pp. e0144117 ◽  
Author(s):  
Øystein Skagseth ◽  
Aril Slotte ◽  
Erling Kåre Stenevik ◽  
Richard D. M. Nash
Keyword(s):  
Clupea Harengus ◽  
Coastal Current ◽  
Norwegian Coastal Current ◽  
High Recruitment

Analysis of Micro-Explosion Phenomenon in a Constant Volume Chamber by Butanol-Biodiesel-Diesel Blend Fuel

2012 ◽  
Vol 443-444 ◽  
pp. 996-1006 ◽  
Author(s):  
Yu Liu ◽  
Jun Li ◽  
Ying Gao ◽  
Xin Mei Yuan
Keyword(s):  
Ambient Temperature ◽  
High Speed ◽  
Fuel Injection ◽  
Combustion Process ◽  
Constant Volume ◽  
Liquid Jet ◽  
Penetration Length ◽  
Temperature Conditions ◽  
Constant Volume Chamber ◽  
Jet Penetration

Different blend ratio of ternary component fuel was tested inside a constant volume chamber to investigate fuel injection and combustion under similar real engine working conditions. Because liquid spray light scattering is the different reflective rate from the liquid droplets and its surrounding background, butanol-biodiesel-diesel liquid jet penetration length can be highlighted in the images taken by high speed camera. Various ambient temperatures from 800K to 1200K and fuel composition were investigated. Measured results showed that sudden but repeatable drop of liquid jet penetration length at constant ambient temperature conditions of 800K and 900K. With ambient temperature increasing, this phenomenon became weak and disappeared. So more works focus on non-combusting experiments in order to delete combustion reflect. With butanol and biodiesel content increasing, micro explosion becomes prone excited and more violent because of the enlarged differences in volatilities and boiling point among the components. It is concluded that micro explosion which will distinctly enhances premixed combustion process and heat release rate but it present under certain initial ambient temperature conditions only and the light fuel content shouldn’t be lower than 10%.

Fickian Transport and the Dispersal of Fish Larvae in Estuaries

1982 ◽  
Vol 39 (8) ◽  
pp. 1150-1163 ◽  
Author(s):  
L. Fortier ◽  
W. C. Leggett
Keyword(s):  
Vertical Distribution ◽  
Fish Larvae ◽  
Sampling Period ◽  
Clupea Harengus ◽  
Tidal Mixing ◽  
Larval Abundance ◽  
Lawrence Estuary ◽  
Larval Stages ◽  
Diel Vertical Migrations ◽  
Average Size

We studied the regulation of ichthyoplankton dispersion in the two-layer circulation of the St. Lawrence upper estuary by determining larval abundance and vertical distribution during high frequency sampling at three stations in May, June, and July, 1979. Monthly variations in capelin (Mallotus villosus) and Atlantic herring (Clupea harengus harengus) abundance were in agreement with the seasonal trends previously reported. Capelin larvae were concentrated in the surface layer, a situation which resulted in seaward drift. No significant growth was observed over the 60-d sampling period indicating continuous recruitment to, and removal from, the sampling area. Herring larvae were concentrated in the deep layer and were carried landward. The average size of herring larvae increased from the downstream to the upstream stations. Short-term fluctuations in the abundance and vertical distribution of the two species were interpreted in terms of the Fickian representation of transport for partially mixed estuaries. The major source of variation in abundance, at a given station, was the tidal advection of horizontal gradients. Capelin larvae and herring larvae smaller than 10 mm did not actively cross the pycnocline and were not submitted to the diffusive effect of the vertical current shear. The dispersal of these larvae was apparently passive. Herring larvae larger than 10 mm performed diel vertical migrations across the pycnocline and were dispersed in the horizontal plane at a faster rate than a passive contaminant of the environment. We conclude that the Fickian approach can be profitably applied to studies of dispersal and mortality of early larval stages of fish in estuaries.Key words: ichthyoplankton, St. Lawrence estuary, dispersion, transport, vertical distribution, diel migrations, variability, abundance, tidal mixing, Fickian

scholarly journals Estimated food consumption of minke whales Balaenoptera acutorostrata in Northeast Atlantic waters in 1992-1995

2000 ◽  
Vol 2 ◽  
pp. 65 ◽  
Author(s):  
Lars P Folkow ◽  
Tore Haug ◽  
Kjell T Nilssen ◽  
Erling S Nordøy
Keyword(s):  
Barents Sea ◽  
Regional Distribution ◽  
Clupea Harengus ◽  
Mortality Factor ◽  
Point Estimate ◽  
Melanogrammus Aeglefinus ◽  
Balaenoptera Acutorostrata ◽  
Northeast Atlantic ◽  
Minke Whales ◽  
Prey Items

Data on energy requirements, diet composition, and stock size were combined to estimate the consumption of various prey species by minke whales (Balaenoptera acutorostrata) in Northeast Atlantic waters. In the period 1992-1995, the stock of 85,000 minke whales appeared to have consumed more than 1.8 million tonnes of prey per year in coastal waters off northern Norway, in the Barents Sea and around Spitsbergen during an assumed 6 month stay between mid-April and mid-October.Uncertainties in stock estimates suggest a 95% confidence range of 1.4 - 2.1 million tonnes. The point estimate was composed of 602,000 tonnes of krill Thysanoessa spp., 633,000 tonnes of herring Clupea harengus, 142,000 tonnes of capelin Mallotus villosus, 256,000 tonnes of cod Gadus morhua, 128,000 tonnes of haddock Melanogrammus aeglefinus and 54,500 tonnes of other fish species, including saithe Pollaehius virens and sand eel Ammodytes sp. Consumption of various prey items by minke whales may represent an important mortality factor for some of the species. For example, the estimated annual consumption of herring corresponds to about 70% of the herring fisheries in the Northeast Atlantic in 1995. Minke whale diets are subject to year-to-year variations due to changes in the resource base in different feeding areas. Thus, the regional distribution of consumption of different prey items is highly dynamic.

scholarly journals Feeding of mature cod (Gadus morhua) on the spawning grounds in Lofoten

2008 ◽  
Vol 65 (4) ◽  
pp. 571-580 ◽  
Author(s):  
Kathrine Michalsen ◽  
Edda Johannesen ◽  
Bjarte Bogstad
Keyword(s):  
Diet Composition ◽  
Gadus Morhua ◽  
Barents Sea ◽  
Lower Proportion ◽  
Clupea Harengus ◽  
Stomach Fullness ◽  
Spawning Grounds ◽  
Spawning Period ◽  
Established Fact ◽  
A Minor

Abstract Michalsen, K., Johannesen, E., and Bogstad, B. 2008. Feeding of mature cod (Gadus morhua) on the spawning grounds in Lofoten. – ICES Journal of Marine Science, 65: 571–580. Many authors state that cod (Gadus morhua) do not feed during the spawning period. However, this more or less established fact has rarely been investigated in the field. Here, the content of stomachs from Northeast Arctic cod (NEAC) and Norwegian coastal cod (NCC) sampled from the spawning ground in Lofoten were examined over a 10-year period (1996–2006). The occurrence of food in the stomachs of spawning cod, stomach fullness, diet composition, and variation in these variables between NEAC and NCC, year, and sex were analysed and compared. The analysis shows that cod do feed, even when they are in a spawning state. NCC had a lower proportion of empty stomachs and the stomachs were fuller than those from NEAC. Females had a lower proportion of empty stomachs than males and their stomachs were in general fuller. Herring (Clupea harengus) dominated the diet of cod. However, cod consumption of herring on the spawning grounds seems to be a minor source of mortality on herring. Although spawning cod do feed, the proportion of empty stomachs was higher and stomach fullness was lower than in stomachs of NEAC from the Barents Sea.

scholarly journals Marine mammals' influence on ecosystem processes affecting fisheries in the Barents Sea is trivial

2009 ◽  
Vol 5 (2) ◽  
pp. 204-206 ◽  
Author(s):  
Peter J Corkeron
Keyword(s):  
Marine Mammal ◽  
Marine Mammals ◽  
Gadus Morhua ◽  
Fishery Management ◽  
Barents Sea ◽  
Scientific Evidence ◽  
Primary Component ◽  
Clupea Harengus ◽  
Balaenoptera Acutorostrata ◽  
The Barents Sea

Some interpretations of ecosystem-based fishery management include culling marine mammals as an integral component. The current Norwegian policy on marine mammal management is one example. Scientific support for this policy includes the Scenario Barents Sea (SBS) models. These modelled interactions between cod, Gadus morhua , herring, Clupea harengus , capelin, Mallotus villosus and northern minke whales, Balaenoptera acutorostrata . Adding harp seals Phoca groenlandica into this top-down modelling approach resulted in unrealistic model outputs. Another set of models of the Barents Sea fish–fisheries system focused on interactions within and between the three fish populations, fisheries and climate. These model key processes of the system successfully. Continuing calls to support the SBS models despite their failure suggest a belief that marine mammal predation must be a problem for fisheries. The best available scientific evidence provides no justification for marine mammal culls as a primary component of an ecosystem-based approach to managing the fisheries of the Barents Sea.

Vertical distribution of tintinnids and associated microplankton in the upper layer of the Barents Sea

Sarsia ◽  
1991 ◽  
Vol 76 (3) ◽  
pp. 141-151 ◽  
Author(s):  
Demetrio Boltovskoy ◽  
Sandra M. Vivequin ◽  
Neil R. Swanberg
Keyword(s):  
Vertical Distribution ◽  
Barents Sea ◽  
The Barents Sea
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