Biomass transport to and from an upper estuarine area by migration of juvenile Atlantic herring Clupea harengus

2000 ◽  
Vol 57 (7) ◽  
pp. 1404-1409 ◽  
Author(s):  
Joachim Maes ◽  
Frans Ollevier
Keyword(s):  
Marine Species ◽  
Growth Conditions ◽  
Clupea Harengus ◽  
Fish Migration ◽  
Atlantic Herring ◽  
Seaward Migration ◽  
Fish Migrations ◽  
The Difference ◽  
European Estuaries

A model describing fish abundance resulting from fish migration and mortality in an upper estuary is presented. This model can be used to estimate biomass transports by fish migrations between estuary and sea and to assess production assimilated in the estuary. It was applied to herring Clupea harengus L., a marine species with 0+ juveniles that migrate during winter to temperate European estuaries. It was shown that different mortality regimes greatly affected the number of fish that eventually emigrated and, hence, the biomass that was exported during the seaward migration. The difference between imported and exported biomass was assessed under different growth conditions and varied from positive to negative as mortality rates increased. The discrepancy between export of biomass and in situ produced biomass showed that fish production was not necessarily transported to the sea when emigrating. It was tentatively concluded that export of biomass out of the estuary only occurs if populations move seaward before winter.

Potential of Eimeria sardinae (Apicomplexa: Eimeridae) Oocysts for Distinguishing between Spawning Groups and between First- and Repeat-Spawning Atlantic Herring (Clupea harengus harengus)

1987 ◽  
Vol 44 (7) ◽  
pp. 1379-1385 ◽  
Author(s):  
Sharon E. McGladdery
Keyword(s):  
Clupea Harengus ◽  
Maturity Stage ◽  
Atlantic Herring ◽  
Spawning Grounds ◽  
The Difference ◽  
Mature Fish ◽  
Clupea Harengus Harengus ◽  
Surrounding Areas ◽  
Immature Fish ◽  
Northeastern Atlantic

Prevalence of Eimeria sardinae oocysts was closely correlated with the maturity stage of the testes of Atlantic herring (Clupea harengus harengus). Prevalence was low in testes of immature fish, increased in ripe and spawning fish, and decreased in postspawning fish. No correlation was found between prevalence and age of spawning herring. The uniformly high prevalences in mature fish indicated the efficiency of transmission on the spawning grounds, where infective oocysts are released. Infection of first-spawning herring (approximately age 3) indicated that the oocysts may be dispersed to surrounding areas or immature fish may associate with spawning aggregations. Therefore, this parasite could not be used to distinguish first from repeat spawners. Prevalence oF E. sardinae peaked in May and September, and possibly in June and early July, thereby distinguishing two, and possibly three, spawning groups. A previous study indicated no correlation between maturity stage and infections by E. sardinae in northeastern Atlantic herring. The difference between the two sides of the Atlantic is attributed to greater mixing of immature and adult herring around spawning grounds and/or greater dispersal of infective oocysts from spawning grounds in the northeastern Atlantic, compared with those in the northwest.

In situ acoustic estimates of the swimbladder volume of Atlantic herring (Clupea harengus)

2004 ◽  
Vol 61 (3) ◽  
pp. 323-337 ◽  
Author(s):  
Redwood W. Nero ◽  
Charles H. Thompson ◽  
J. Michael Jech
Keyword(s):  
Gulf Of Maine ◽  
Clupea Harengus ◽  
Sea Surface ◽  
Atlantic Herring ◽  
Acoustic Measurements ◽  
Neutral Buoyancy ◽  
Fish Weight ◽  
Neutrally Buoyant ◽  
Boyle’S Law

Abstract Acoustic measurements at 1.5–5 kHz on fish in the Gulf of Maine showed a swimbladder-resonance peak near 2.5 kHz at 160–190-m depth. Midwater trawls confirmed that the fish were likely to be Atlantic herring (Clupea harengus) of 19–29 cm length. Calculation using a model of swimbladder resonance gives swimbladder volumes of 1.2% of fish weight at 160–190 m. Extrapolation of this volume of gas using Boyle's Law suggests that at the sea surface, these herring would need to inflate their swimbladders by up to five to six times the volume required for neutral buoyancy. If these fish were to maintain this volume of gas with surface “gulping”, they would need to submerge from the sea surface with a 30% excess buoyancy. In general, swimbladders of the Clupeidae may have greater volumes of gas than if the fish were neutrally buoyant at the sea surface and the interpretation of HF-echosounder surveys may be additionally complex when the volume of gas and swimbladder volume are difficult to predict. Mechanisms of how herring obtain additional swimbladder gas are discussed.

In situ acoustic estimates of the swimbladder volume of Atlantic herring, Clupea harengus

2002 ◽  
Vol 112 (5) ◽  
pp. 2207-2207
Author(s):  
Redwood W. Nero ◽  
Charles H. Thompson ◽  
J. Michael Jech
Keyword(s):  
Clupea Harengus ◽  
Atlantic Herring

scholarly journals The Dielectric Properties of Antarctic Ice

1975 ◽  
Vol 15 (73) ◽  
pp. 39-48 ◽  
Author(s):  
W. J. Fitzgerald ◽  
J. G. Paren
Keyword(s):  
Dielectric Response ◽  
Impurity Content ◽  
Drill Hole ◽  
Growth Conditions ◽  
Frequency Range ◽  
Polar Ice ◽  
Polycrystalline Ice ◽  
The Difference ◽  
The Antarctic

AbstractTwo 0.5 m cores from "Byrd" station, Antarctica have been studied in the laboratory, one from a shallow depth (155 m) and the other from the zone where recrystallization has given a vertical c-axis fabric, and the air in situ is thought to be in clathrate form (1 424 m). The dielectric response has been studied in the frequency range 60 Hz to 10 kHz, and in the temperature range — 6° C to —6o° C. The behaviour observed is markedly different from that of "pure" polycrystalline ice such as may be made by slowly freezing distilled de-ionized water and is thus at variance with the conclusions of Rogers (unpublished) who deduced, from measurements of the admittance of a dipole probe lowered through the fluid-filled drill hole at "Byrd", that the ice surrounding the hole had a dielectric response similar to that of "pure" ice. The Antarctic ice is shown to have properties similar to those of the ice from "Camp Century" and "Site 2" in Greenland studied by Paren (1973). In an attempt to discover what factors determine the difference in electrical behaviour between polar ice and pure ice, some samples were melted and subsequently refrozen slowly. Their dielectric response was similar to that of pure polycrystalline ice. These results are discussed in connection with the impurity content and growth conditions of the ices.

scholarly journals The Dielectric Properties of Antarctic Ice

1975 ◽  
Vol 15 (73) ◽  
pp. 39-48 ◽  
Author(s):  
W. J. Fitzgerald ◽  
J. G. Paren
Keyword(s):  
Dielectric Response ◽  
Impurity Content ◽  
Drill Hole ◽  
Growth Conditions ◽  
Frequency Range ◽  
Polar Ice ◽  
Polycrystalline Ice ◽  
The Difference ◽  
The Antarctic

AbstractTwo 0.5 m cores from "Byrd" station, Antarctica have been studied in the laboratory, one from a shallow depth (155 m) and the other from the zone where recrystallization has given a verticalc-axis fabric, and the airin situis thought to be in clathrate form (1 424 m). The dielectric response has been studied in the frequency range 60 Hz to 10 kHz, and in the temperature range — 6° C to —6o° C. The behaviour observed is markedly different from that of "pure" polycrystalline ice such as may be made by slowly freezing distilled de-ionized water and is thus at variance with the conclusions of Rogers (unpublished) who deduced, from measurements of the admittance of a dipole probe lowered through the fluid-filled drill hole at "Byrd", that the ice surrounding the hole had a dielectric response similar to that of "pure" ice. The Antarctic ice is shown to have properties similar to those of the ice from "Camp Century" and "Site 2" in Greenland studied by Paren (1973). In an attempt to discover what factors determine the difference in electrical behaviour between polar ice and pure ice, some samples were melted and subsequently refrozen slowly. Their dielectric response was similar to that of pure polycrystalline ice. These results are discussed in connection with the impurity content and growth conditions of the ices.

scholarly journals Adaptation to seasonal reproduction and thermal minima-related factors drives fine-scale divergence despite gene flow in Atlantic herring populations

2019 ◽  
Author(s):  
Angela P. Fuentes-Pardo ◽  
Christina Bourne ◽  
Rabindra Singh ◽  
Kim Emond ◽  
Lisa Pinkham ◽  
...  
Keyword(s):  
Local Adaptation ◽  
Marine Species ◽  
Clupea Harengus ◽  
Intraspecific Diversity ◽  
Disruptive Selection ◽  
Population Subdivision ◽  
Seasonal Reproduction ◽  
Atlantic Herring ◽  
Fine Scale ◽  
High Fecundity

AbstractHigh connectivity and low potential for local adaptation have been common assumptions for most marine species, given their usual high fecundity and dispersal capabilities. Recent genomic studies however, have disclosed unprecedented levels of population subdivision in what were previously presumed to be panmictic or nearly panmictic species. Here we analyzed neutral and adaptive genetic variation at the whole-genome level in Atlantic herring (Clupea harengusL.) spawning aggregations distributed across the reproductive range of the species in North America. We uncovered fine-scale population structure at putatively adaptive loci, despite low genetic differentiation at neutral loci. Our results revealed an intricate pattern of population subdivision involving two overlapping axes of divergence: a temporal axis determined by seasonal reproduction, and a spatial axis defined by a latitudinal cline establishing a steep north-south genetic break. Genetic-environment association analyses indicated that winter sea-surface temperature is the best predictor of the spatial structure observed. Thousands of outlier SNPs distributed along specific parts of the genome spanning numerous candidate genes underlined each pattern of differentiation, forming so-called “genomic regions or islands of divergence”. Our results indicate that timing of reproduction and latitudinal spawning location are features under disruptive selection leading to local adaptation in the herring. Our study highlights the importance of preserving functional and neutral intraspecific diversity, and the utility of an integrative seascape genomics approach for disentangling intricate patterns of intraspecific diversity in highly dispersive and abundant marine species.

The reaction of a captive herring school to playbacks of a noise-reduced and a conventional research vessel

2015 ◽  
Vol 72 (4) ◽  
pp. 491-499 ◽  
Author(s):  
Nils Olav Handegard ◽  
Alex De Robertis ◽  
Guillaume Rieucau ◽  
Kevin Boswell ◽  
Gavin J. Macaulay
Keyword(s):  
Sound Pressure ◽  
Low Frequency ◽  
Clupea Harengus ◽  
Research Vessel ◽  
Frequency Noise ◽  
Atlantic Herring ◽  
Low Frequencies ◽  
Vessel Noise ◽  
Fish Avoidance

Fish avoidance of vessels can bias fisheries-independent surveys. To understand these biases, recordings of underwater radiated vessel noise from a noise-reduced and a conventional research vessel were played back at the same sound pressure levels (SPL) as experienced in situ to Atlantic herring (Clupea harengus) in a net pen at two different densities. The noise-reduced vessel recording was also scaled to the same SPL as the conventional vessel to test if characteristics other than SPL affected the reactions. Overall, only weak reactions were observed, but reactions were stronger in the low-density school, in the middle of the pen, and for the scaled silent vessel compared with the conventional vessel. These observations may be attributable to the lack of low frequencies (<50 Hz) in the playbacks, differential motivation for reaction driven by fish density, higher low-frequency noise in the middle of the pen (but lower overall SPL), and characteristics other than SPL. These results call into question the use of SPL as a proxy for fish reaction to vessels as used in standards for construction of research vessels.

Comparison of Mammography and Ultrasonography for Tumor Size of DCIS of Breast Cancer

2019 ◽  
Vol 15 (2) ◽  
pp. 209-213
Author(s):  
Yu Wang ◽  
Jiantao Wang ◽  
Haiping Wang ◽  
Xinyu Yang ◽  
Liming Chang ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Correlation Coefficient ◽  
Tumor Size ◽  
Ductal Carcinoma ◽  
Pearson Correlation ◽  
Dense Breast ◽  
Pathological Examination ◽  
Negative Group ◽  
The Difference

Objective: Accurate assessment of breast tumor size preoperatively is important for the initial decision-making in surgical approach. Therefore, we aimed to compare efficacy of mammography and ultrasonography in ductal carcinoma in situ (DCIS) of breast cancer. Methods: Preoperative mammography and ultrasonography were performed on 104 women with DCIS of breast cancer. We compared the accuracy of each of the imaging modalities with pathological size by Pearson correlation. For each modality, it was considered concordant if the difference between imaging assessment and pathological measurement is less than 0.5cm. Results: At pathological examination tumor size ranged from 0.4cm to 7.2cm in largest diameter. For mammographically determined size versus pathological size, correlation coefficient of r was 0.786 and for ultrasonography it was 0.651. Grouped by breast composition, in almost entirely fatty and scattered areas of fibroglandular dense breast, correlation coefficient of r was 0.790 for mammography and 0.678 for ultrasonography; in heterogeneously dense and extremely dense breast, correlation coefficient of r was 0.770 for mammography and 0.548 for ultrasonography. In microcalcification positive group, coeffient of r was 0.772 for mammography and 0.570 for ultrasonography. In microcalcification negative group, coeffient of r was 0.806 for mammography and 0.783 for ultrasonography. Conclusion: Mammography was more accurate than ultrasonography in measuring the largest cancer diameter in DCIS of breast cancer. The correlation coefficient improved in the group of almost entirely fatty/ scattered areas of fibroglandular dense breast or in microcalcification negative group.

Growth of Epitaxial IrSi3 Layers on Si(111)

1989 ◽  
Vol 160 ◽  
Author(s):  
T. L. Lin ◽  
C. W. Nieh
Keyword(s):  
Surface Morphology ◽  
Molecular Beam ◽  
Solid Phase ◽  
Single Mode ◽  
Growth Conditions ◽  
Tem Analysis ◽  
Mbe Growth ◽  
Good Surface ◽  
Transmission Electron

AbstractEpitaxial IrSi3 films have been grown on Si (111) by molecular beam epitaxy (MBE) at temperatures ranging from 630 to 800 °C and by solid phase epitaxy (SPE) at 500 °C. Good surface morphology was observed for IrSi3 layers grown by MBE at temperatures below 680 °C, and an increasing tendency to form islands is noted in samples grown at higher temperatures. Transmission electron microscopy (TEM) analysis reveals that the IrSi3 layers grow epitaxially on Si(111) with three epitaxial modes depending on the growth conditions. For IrSi3 layers grown by MBE at 630 °C, two epitaxial modes were observed with ~ 50% area coverage for each mode. Single mode epitaxial growth was achieved at a higher MBE growth temperature, but with island formation in the IrSi3 layer. A template technique was used with MBE to improve the IrSi3 surface morphology at higher growth temperatures. Furthermore, single-crystal IrSi3 was grown on Si(111) at 500 °C by SPE, with annealing performed in-situ in a TEM chamber.

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