scholarly journals Varying relationships between fish length and scale size under changing environmental conditions – Multidecadal perspective in Atlantic herring

2022 ◽  
Vol 134 ◽  
pp. 108494
Author(s):  
Szymon Smoliński ◽  
Florian Berg
Keyword(s):  
Environmental Conditions ◽  
Fish Length ◽  
Atlantic Herring ◽  
Scale Size

The reappearance of spawning Atlantic herring (Clupea harengus) on Aberdeen Bank (North Sea) in 1983 and its relationship to environmental conditions

1999 ◽  
Vol 56 (11) ◽  
pp. 2051-2061 ◽  
Author(s):  
Ad Corten
Keyword(s):  
North Sea ◽  
Environmental Conditions ◽  
Clupea Harengus ◽  
Copepod Species ◽  
Simultaneous Increase ◽  
Atlantic Herring ◽  
Southern Population ◽  
Latitudinal Distribution ◽  
Spawning Ground ◽  
Northern North Sea

Evidence is presented in support of the hypothesis that the reappearance of spawning Atlantic herring (Clupea harengus) on Aberdeen Bank in 1983, after an absence of 16 years, was related to an increased Atlantic inflow in the area. Two Atlantic copepod species, Metridia lucens and Candacia armata, showed a simultaneous increase in the years when spawning herring returned to Aberdeen Bank. During the late 1960s, both species declined at the time when the spawning population on Aberdeen Bank disappeared. Earlier work has demonstrated that an increased Atlantic inflow results in a southward displacement of plankton concentrations and feeding herring in the northwestern North Sea. I hypothesize that such a southern distribution of the herring stock, caused indirectly by the increased Atlantic inflow, influenced recruit spawners to choose the nearby Aberdeen Bank as their spawning ground in 1983. Fluctuations of the spawning populations in the northern North Sea during earlier decades are explained by switches of recruitment between the northern and southern population, as a result of variations in latitudinal distribution of the recruiting year-class.

Similarity of Otolith Nuclei in Spring- and Autumn-Spawning Atlantic Herring in the Southern Gulf of St. Lawrence

1969 ◽  
Vol 26 (7) ◽  
pp. 1889-1898 ◽  
Author(s):  
Shoukry N. Messieh
Keyword(s):  
Fish Length ◽  
Atlantic Herring ◽  
Frequency Distributions ◽  
Hydrographic Conditions ◽  
The Right ◽  
Optical Appearance

The optical appearance of otolith nuclei was found inadequate for separating spring and autumn spawning herring in the southern Gulf of St. Lawrence. The nuclei of both groups of spawners in 1966 ranged from distinctly hyaline to completely opaque, and the right and left nuclei differed in some fish. Frequency distributions of hyaline and opaque nuclei and of combinations of these types were similar for the two groups of spawners. Frequency distributions of fish length at time of formation of the first annulus did not differ in relation to type of otolith nucleus though they did differ in relation to the widths of the central areas of the scales. The similar frequencies of the various types of nuclei in the two spawning groups may result from the variable hydrographic conditions in the area.

scholarly journals Connectivity effects on productivity, stability, and persistence in a herring metapopulation model

2009 ◽  
Vol 66 (8) ◽  
pp. 1726-1732 ◽  
Author(s):  
David H. Secor ◽  
Lisa A. Kerr ◽  
Steven X. Cadrin
Keyword(s):  
Environmental Conditions ◽  
Clupea Harengus ◽  
Metapopulation Dynamics ◽  
Storage Effect ◽  
Atlantic Herring ◽  
Metapopulation Model ◽  
Environmental Forcing ◽  
Two Component ◽  
Age Structured ◽  
Age Structured Model

Abstract Secor, D. H., Kerr, L. A., and Cadrin, S. X. 2009. Connectivity effects on productivity, stability, and persistence in a herring metapopulation model. – ICES Journal of Marine Science, 66: 1726–1732. Diverse and interacting spawning groups of Atlantic herring (Clupea harengus) have varying degrees of independence to environmental conditions. How these population components respond independently to the same set of environmental conditions, and are connected through straying or entrainment, will contribute to the aggregate metapopulation dynamics. The consequences of connectivity for productivity, stability, and persistence were evaluated in an age-structured model of a two-component metapopulation. Simulation scenarios of straying and entrainment were developed to examine the effects of component interchange and recruitment covariance on metapopulation attributes. Asynchronous component responses should result in reduced variance in metapopulation dynamics, which was measured as the portfolio effect (PE). Most types and magnitudes of connectivity reduced metapopulation productivity and stability. Increased connectivity tended to increase instability of a component by distributing the effect of strong year classes among components and disrupting the “storage effect” within components. Density-dependent straying and entrainment, respectively, showed stabilizing and destabilizing feedback cycles on metapopulation stability and persistence. Furthermore, high rates of connectivity tended to result in increased synchronous responses between components and depressed metapopulation productivity, stability, and PE. Exploitation on a metapopulation should similarly depress independence among components because high mortality will dampen component responses to environmental forcing.

Vibration Isolator System for Electron Microscope

1990 ◽  
Vol 48 (1) ◽  
pp. 182-183
Author(s):  
K. Ohi ◽  
M. Mizuno ◽  
T. Kasai ◽  
Y. Ohkura ◽  
K. Mizuno ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Magnetic Fields ◽  
Environmental Conditions ◽  
Vibration Isolator ◽  
Air Conditioners ◽  
Vibration Isolators ◽  
Large Size ◽  
Electron Microscopes

In recent years, with electron microscopes coming into wider use, their installation environments do not necessarily give their performance full play. Their environmental conditions include air-conditioners, magnetic fields, and vibrations. We report a jointly developed entirely new vibration isolator which is effective against the vibrations transmitted from the floor.Conventionally, large-sized vibration isolators which need the digging of a pit have been used. These vibration isolators, however, are large present problems of installation and maintenance because of their large-size.Thus, we intended to make a vibration isolator which1) eliminates the need for changing the installation room2) eliminates the need of maintenance and3) are compact in size and easily installable.

The influence of external conditions on sound pressure in the pistonphone at the infrasound frequency range

2020 ◽  
pp. 67-72
Author(s):  
A. V. Konkov ◽  
D. V. Golovin
Keyword(s):  
Environmental Conditions ◽  
Sound Pressure ◽  
Primary Method ◽  
Frequency Range ◽  
External Conditions ◽  
Numerical Estimations

The influence of environmental conditions on a sound pressure reproduced by the primary method in the measuring chambers of the Pistonphone in the frequency range from 1 mHz to 250 Hz is estimated. Numerical estimations of influence of environmental conditions on sound pressure in pistonphone measuring chambers are given and special requirements to system of maintenance of required external conditions are specified.

Disentangling the role of shared ancestry and the environment on leaf stable isotopes

2019 ◽  
Author(s):  
Marko J. Spasojevic ◽  
Sören Weber1
Keyword(s):  
Stable Isotopes ◽  
Environmental Conditions ◽  
Evolutionary History ◽  
Environmental Control ◽  
Phylogenetic Signal ◽  
Individual Species ◽  
Habitat Types ◽  
Δ13c And Δ15n ◽  
Environmental Controls ◽  
Shared Ancestry

Stable carbon (C) and nitrogen (N) isotopes in plants are important indicators of plant water use efficiency and N acquisition strategies. While often regarded as being under environmental control, there is growing evidence that evolutionary history may also shape variation in stable isotope ratios (δ13C and δ15N) among plant species. Here we examined patterns of foliar δ13C and δ15N in alpine tundra for 59 species in 20 plant families. To assess the importance of environmental controls and evolutionary history, we examined if average δ13C and δ15N predictably differed among habitat types, if individual species exhibited intraspecific trait variation (ITV) in δ13C and δ15N, and if there were a significant phylogenetic signal in δ13C and δ15N. We found that variation among habitat types in both δ13C and δ15N mirrored well-known patterns of water and nitrogen limitation. Conversely, we also found that 40% of species exhibited no ITV in δ13C and 35% of species exhibited no ITV in δ15N, suggesting that some species are under stronger evolutionary control. However, we only found a modest signal of phylogenetic conservatism in δ13C and no phylogenetic signal in δ15N suggesting that shared ancestry is a weaker driver of tundra wide variation in stable isotopes. Together, our results suggest that both evolutionary history and local environmental conditions play a role in determining variation in δ13C and δ15N and that considering both factors can help with interpreting isotope patterns in nature and with predicting which species may be able to respond to rapidly changing environmental conditions.

Freshwater Mussel (Batissa violacea) Fishery and its Value in Fiji

2019 ◽  
Vol 39 (1) ◽  
Author(s):  
Jimaima Lako ◽  
Nanise Kuridrani ◽  
Milika Sobey
Keyword(s):  
Value Chain ◽  
Environmental Conditions ◽  
Rural Women ◽  
Freshwater Mussel ◽  
Face To Face

This paper examines the local freshwater mussel, or kai (Batissa violacea), fishery value chain, its values and contribution to the livelihood of people in Viti Levu, Fiji. The assessment was performed through face-to-face interviews, with the use of semi-structured questionnaires administered to 125 actors. A walk through the value-chain was also conducted that confirmed the sites’ environmental conditions. Results revealed that even though the kai fishery is dominated by rural women, men were also employed as kai processors, transporting agents and exporters. This fishery generated at least 58 other employments through the 500 kai harvesters within the five major provinces understudy. These were drivers, boat builders, retailers, processors, exporters, and harvesters. Three sales pathways were identified that determined the revenues and profits: (i) harvesters sell own harvests directly to the consumer at the municipal markets, (ii) harvesters sell through intermediary traders to consumers, and (iii) harvesters sell through processors to supermarkets, hotels or exporters. When revenues and profits were calculated, harvesters earned much less, compared to intermediary traders, processors, and exporters. Major constraints include continuous reduction in catch size of kai, lack of transport, and marketing at the local municipal markets that require improvements.

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