Herring submesoscale dynamics through a major spawning wave: duration, abundance fluctuation, distribution, and schooling

2016 ◽  
Vol 74 (3) ◽  
pp. 717-727
Author(s):  
Georg Skaret ◽  
Aril Slotte
Keyword(s):  
Significant Proportion ◽  
Clupea Harengus ◽  
Night Time ◽  
State Dependent ◽  
Swimming Depth ◽  
Spawning Stock ◽  
Schooling Behaviour ◽  
Bottom Depth ◽  
Short Time ◽  
Observation Period

In this study, a series of 17 repeated acoustic trawl surveys within a ca. 1500 km2 area covering the major spawning location for Norwegian spring-spawning herring (Clupea harengus) was conducted over a period of about 1 month. Local herring abundance increased from ca. 25 000 to 237 000 t, a significant proportion of the total spawning stock, in just 3 d and subsequently decreased to <30 000 t over the next 7 d. The abundance change was due to a single major spawning wave developing over the observation period, and an estimated 46 000 t of eggs and milt were deposited during the short time spent at the spawning ground. There was no difference in spawning activity between day and night, but herring were more associated with deep trenches and also generally stayed deeper in more dense schools during daylight than night-time. Schooling behaviour and distribution were also strongly state-dependent, and both school swimming depth and school height decreased as spawning progressed, as did the bottom depth where the schools were located. The massive herring spawning events seem to be low-risk adaptations to an environment where predators are abundant, with rapid spawning in huge aggregations as a strategy for predator swamping.

Mammographic Fine Needle Biopsy of Non-Palpable Breast Lesions

1984 ◽  
Vol 25 (4) ◽  
pp. 273-276 ◽  
Author(s):  
M. Kehler ◽  
U. Albrechtsson
Keyword(s):  
Diagnostic Accuracy ◽  
Needle Biopsy ◽  
Fine Needle Biopsy ◽  
Breast Lesions ◽  
Malignant Cells ◽  
Fine Needle ◽  
The Past ◽  
Palpable Breast ◽  
Short Time ◽  
Observation Period

Results with a previously described device for fine needle biopsies of non-palpable breast lesions are reported. During the past 5 years 182 biopsies were performed and 133 of these yielded diagnostic cell material. In the series, 41 carcinomas were found and fine needle biopsy in all demonstrated malignant or probably malignant cells. In the biopsies evaluated as benign or probably benign, malignancy has not been found during the observation period of 4 to 59 months (mean 21.5 months). The device described is cheap and biopsy is easily performed and, if necessary, repeated in a short time. The diagnostic accuracy is high and carcinomas as small as 3 mm in diameter have been diagnosed.

scholarly journals Effects of suckling on milk yield and milk composition of dairy cows in cow–calf contact systems

2020 ◽  
Vol 87 (S1) ◽  
pp. 133-137
Author(s):  
Kerstin Barth
Keyword(s):  
Milk Yield ◽  
Mixed Models ◽  
Milk Composition ◽  
Control Group ◽  
Research Station ◽  
Suckling Period ◽  
Night Time ◽  
Milk Protein Content ◽  
Cow Calf ◽  
Short Time

AbstractIn this research communication I show the effect of various cow–calf contact systems on milk yield and milk composition during the periods when calves where allowed to suckle their dams and after the calves were separated in comparison to cows that were only machine milked throughout their lactation. Analyses were based on four different experiments, but conducted at the same research station and under comparable housing and feeding conditions. Nursing dams had contact to their calves during the whole day, during night-time or only twice per day shortly before milking. A control group of cows that had no contact to their offspring was part of every experiment. Data of the regular monthly milk recordings were analysed with linear mixed models. Results showed a significant effect of the suckling system on the machine milk yield over the whole lactation. While cows with night-time contact reached the milk production level of the control cows, cows with whole day or short-time contact still produced less milk after the calves were separated. Fat content was always lower during the suckling period but not afterwards. The significantly higher milk protein content in dams with calf contact requires further investigation. Somatic cell count in milk of nursing dams was slightly increased, probably due to the exposure of the teats to frequent suckling in addition to machine milkings. In conclusion, cow–calf contact systems influence the performance of cows during and after the suckling period but to varying degrees depending on the system adopted.

scholarly journals Inaccuracies in routinely collected Atlantic herring (Clupea harengus) maturity data and correction using a gonadosomatic index model

2011 ◽  
Vol 91 (7) ◽  
pp. 1477-1487 ◽  
Author(s):  
Lindsay R. McPherson ◽  
Konstantinos Ganias ◽  
C. Tara Marshall
Keyword(s):  
North Sea ◽  
Low Cost ◽  
Gonadosomatic Index ◽  
Clupea Harengus ◽  
Implicit Assumption ◽  
Multinomial Regression ◽  
Index Model ◽  
The North ◽  
Spawning Stock ◽  
The North Sea

Macroscopic maturity staging data are widely used to distinguish between reproductive and non-reproductive individuals. The implicit assumption is that these data are accurate. The accuracy of macroscopic maturity staging of North Sea herring (Clupea harengus) has not been checked since the macroscopic scale was produced in 1961. The aim of this study was to assess the accuracy of macroscopic maturity staging of female North Sea herring by comparison to histological staging and the gonadosomatic index (GSI). Ovary samples were collected during the North Sea Herring Acoustic Survey in 2006 on-board FRV ‘Scotia’ (Scotland) and in 2007 on-board FRV ‘Scotia’ and RV ‘Johan Hjort’ (Norway). Commercial samples were also collected by Marine Scotland, Aberdeen in both years. The maturity staging error was relatively low in 2006 (21% error) but was much higher on-board FRV ‘Scotia’ (57%) and RV ‘Johan Hjort’ (47%) in 2007. There was estimated to be a 27% under-estimation of the spawning stock biomass (SSB) in 2007 due to the differences in the proportion mature but no change in SSB estimates in 2006. GSI cut-off scores, estimated by means of multinomial regression models were successfully able to separate immature females from both mature-active and recovering females; however, there was some overlap between the mature-active and recovering individuals. We conclude that an effective and low-cost means of reducing error in herring maturity studies is the combined use of a four-point macroscopic maturity scale with routinely collected GSI data, the latter acting to validate and fine tune macroscopic staging.

scholarly journals MSY-orientated management of Baltic Sea herring (Clupea harengus) during different ecosystem regimes

2012 ◽  
Vol 69 (2) ◽  
pp. 257-266 ◽  
Author(s):  
Noel M. A. Holmgren ◽  
Niclas Norrström ◽  
Robert Aps ◽  
Sakari Kuikka
Keyword(s):  
Baltic Sea ◽  
Gadus Morhua ◽  
Maximum Sustainable Yield ◽  
Clupea Harengus ◽  
Simultaneous Increase ◽  
Negative Effects ◽  
Planktonic Food ◽  
Spawning Stock ◽  
Food Shortages ◽  
The Baltic

Abstract Holmgren, N. M. A., Norrström, N., Aps, R., and Kuikka, S. 2012. MSY-orientated management of Baltic Sea herring (Clupea harengus) during different ecosystem regimes. – ICES Journal of Marine Science, 69: 257–266. The Baltic Sea ecosystem has undergone dramatic changes, so-called ecosystem regime shifts, during the past four decades. Baltic Sea herring (Clupea harengus) spawning-stock biomass has declined to a third, and weight-at-age has halved as a result of food shortages and competition with sprat (Sprattus sprattus). The management objective for the herring stock is currently in transition from precautionary to maximum sustainable yield (MSY). The main basin Baltic Sea herring was modelled under the current ecosystem regime and the effect of a recovery of the cod (Gadus morhua) stock and the availability of planktonic food to levels found in the early 1980s analysed. A target of FMSY = 0.16 for herring, which should decline to FMSY = 0.10 with recovery of the cod stock, is proposed. An increase in the availability of planktonic food is estimated to more than double the yield at FMSY = 0.27, overriding the negative effects of cod predation should there be a simultaneous increase in both cod and availability of planktonic food. The estimated net increase in yield is 40% at FMSY = 0.20. Functions are presented to calculate FMSY and to estimate the expected yield depending on the abundance of cod and food availability. Retrospective application of the functions is indicative of overfishing of herring in the 1990s and early 2000s, and a net loss in yield, with a landing value of some €440 million.

scholarly journals Comparison of two periods of North Sea herring stock management: success, failure, and monetary value

2007 ◽  
Vol 64 (4) ◽  
pp. 686-692 ◽  
Author(s):  
E. John Simmonds
Keyword(s):  
North Sea ◽  
Scientific Information ◽  
Clupea Harengus ◽  
Stock Management ◽  
Monetary Value ◽  
Management Actions ◽  
Spawning Stock ◽  
Critical Issues ◽  
Management Advice ◽  
Management Issues

Abstract Simmonds, E. J. 2007. Comparison of two periods of North Sea herring stock management: success, failure, and monetary value. – ICES Journal of Marine Science, 64: 686–692. At two points in the past (1970 and 1995), North Sea herring (Clupea harengus) abundance and catches have been in a similar situation: the stock had declined from an earlier high and reached a depleted state with a spawning-stock biomass of around 400 000 t, well below the agreed biomass limit reference point of 800 000 t. Catches were also similar at 600 000 t annually, and too high to be sustainable. A comparison of the scientific advice, the management actions, and their effects on population trends over the periods following these two critical years provides insight into important management issues. The benefits to the industry of the value of the cumulative catch resulting from successful management of this large stock have been proven to outweigh by far the costs of obtaining good management advice. The conclusion is that sound scientific information plays an important role when difficult management issues have to be confronted. However, there are other critical issues, such as the stakeholders' wish to preserve the stock at all costs and a management organization that has authority to take decisions.

scholarly journals Cycles, trends, and residual variation in the Iberian sardine (Sardina pilchardus) recruitment series and their relationship with the environment

2011 ◽  
Vol 69 (5) ◽  
pp. 739-750 ◽  
Author(s):  
M. Begoña Santos ◽  
Rafael González-Quirós ◽  
Isabel Riveiro ◽  
José M. Cabanas ◽  
Carmela Porteiro ◽  
...  
Keyword(s):  
Environmental Variables ◽  
Generalized Additive Models ◽  
Causal Link ◽  
Additive Models ◽  
Dynamic Factor ◽  
Sardina Pilchardus ◽  
Residual Variation ◽  
Stock Biomass ◽  
Spawning Stock ◽  
Short Time

Abstract Santos, M. B., González-Quirós, R., Riveiro, I., Cabanas, J. M., Porteiro, C., and Pierce, G. J. 2012. Cycles, trends, and residual variation in the Iberian sardine (Sardina pilchardus) recruitment series and their relationship with the environment. – ICES Journal of Marine Science, 69: 739–750. Recruitment variability is an important component of the dynamics of Iberian sardine (Sardine pilchardus). Since 2006, poor recruitment has led to a decrease in stock biomass, the latest in a series of such crises for sardine fisheries. Understanding the mechanisms behind recruitment fluctuations has been the objective of many previous studies, and various relationships between recruitment and environmental variables have been proposed. However, such studies face several analytical challenges, including short time-series and autocorrelated data. A new analysis of empirical relationships with environmental series is presented, using statistical methods designed to cope with these issues, including dynamic factor analysis, generalized additive models, and mixed models. Relationships are identified between recruitment and global (number of sunspots), regional (NAOAutumn), and local [winter wind strength, sea surface temperature (SST), and upwelling] environmental variables. Separating these series into trend and noise components permitted further investigation of the nature of the relationships. Whereas the other three environmental variables were related to the trend in recruitment, SST was related to residual variation around the trend, providing stronger evidence for a causal link, possible mechanisms for which are discussed. After the removal of trend and cyclic components, residual variation in recruitment is also weakly related to the previous year's spawning-stock biomass.

scholarly journals The influence of pre-recruitment growth on subsequent growth and age at first spawning in Atlantic herring (Clupea harengus L.)

2003 ◽  
Vol 60 (5) ◽  
pp. 1103-1113 ◽  
Author(s):  
Deirdre Brophy ◽  
Bret S Danilowicz
Keyword(s):  
Clupea Harengus ◽  
First Year ◽  
Fish Length ◽  
Subsequent Growth ◽  
Differential Growth ◽  
Stock Biomass ◽  
Spawning Stock ◽  
Group Spawning ◽  
First Year Of Life ◽  
The Relationship

Abstract Calculation of the spawning stock biomass for fisheries management requires information on the numbers or proportions of fish in each age- or length-group that are mature each year. This study was conducted to determine the relationship between growth and age of first reproduction in herring stocks around Ireland. Measurements of otolith size at the onset of the first annulus (O1) were used to compare growth during the first year of life between 1-, 2-, and 3-group spawning herring collected from spawning grounds in the Celtic Sea over a period of 3 years. The 1-group spawning fish had significantly greater mean O1 measurements, and hence showed faster growth on average during the first year of life than 2- or 3-group spawning fish. Fish that exhibited slow growth during the first year were absent from the adult spawning population at age 1, but occurred at similar levels in the samples of 2- and 3-group spawning fish. Regression of O1 radius on fish length at capture showed that growth during the first year of life had a small but significant effect on subsequent growth up to age 3. The relationship between pre-recruitment growth and subsequent growth and age at first spawning has implications for recruitment patterns of juveniles from different nursery areas and for the lifetime fecundity of population components with differential growth.

scholarly journals Direct and indirect effects of minke whale abundance on cod and herring fisheries: A scenario experiment for the Greater Barents Sea

2000 ◽  
Vol 2 ◽  
pp. 120 ◽  
Author(s):  
Tore Schweder ◽  
Gro S Hagen ◽  
Einar Hatlebakk
Keyword(s):  
Gadus Morhua ◽  
Barents Sea ◽  
Minke Whale ◽  
Clupea Harengus ◽  
Prey Abundance ◽  
Balaenoptera Acutorostrata ◽  
Time Step ◽  
Minke Whales ◽  
Spawning Stock ◽  
Capelin Mallotus Villosus

To study the pattern of interaction between minke whale (Balaenoptera acutorostrata) abundance and the main fisheries in the Greater Barents Sea, a simulation experiment was carried out. The population model involves 4 species interconnected in a food web: cod (Gadus morhua), capelin (Mallotus villosus), herring (Clupea harengus) and minke whales. Minke whales are preying on cod, capelin andherring; cod are preying on (young) cod, capelin and herring; herring in the Barents Sea are preying on capelin; while capelin is a bottom prey in the model. The consumption function for minke whales is non-linear in available prey abundance, and is estimated from stomach content data and prey abundance data. The model is dynamic, with a time step of one month, and there are two areas: the BarentsSea and the Norwegian Sea. Minke whale abundances are kept on fixed levels, while recruitment in fish is stochastic.Cod and herring fisheries are managed by quotas targeting fixed fishing mortalities, while capelin is managed with a view to allow the cod to have enough food and leaving a sufficient spawning stock of capelin. The model is simulated over a period of 100 years for a number of fixed levels of minke whaleabundance, and simulated catches of cod, herring and capelin are recorded.The experiment showed interactions between whale abundance and fish catches to be mainly linear. For cod catches, both the direct effect of whales consuming cod, and the indirect effect due to whales competing with cod for food and otherwise altering the ecosystem, are linear and of equal importance. The net effect on the herring fishery is of the same magnitude as the net effect on the cod fishery, witheach extra whale reducing the catches of both species by some 5 tonnes. These conclusions are conditional on the model and its parameterisation.

scholarly journals Aquatic Mosses as Adaptable Bio-Filters for Heavy Metal Removal from Contaminated Water

2020 ◽  
Vol 21 (13) ◽  
pp. 4769
Author(s):  
Paride Papadia ◽  
Fabrizio Barozzi ◽  
Danilo Migoni ◽  
Makarena Rojas ◽  
Francesco P. Fanizzi ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Metal Removal ◽  
Heavy Metal Removal ◽  
Significant Proportion ◽  
Pollutant Removal ◽  
Polluted Water ◽  
Aquatic Moss ◽  
Aquatic Mosses ◽  
High Concentrations ◽  
Short Time

Heavy metals (HMs) are released into the environment by many human activities and persist in water even after remediation. The efficient filtration of solubilized HMs is extremely difficult. Phytoremediation appears a convenient tool to remove HMs from polluted water, but it is limited by the choice of plants able to adapt to filtration of polluted water in terms of space and physiological needs. Biomasses are often preferred. Aquatic moss biomasses, thanks to gametophyte characteristics, can act as live filtering material. The potential for phytoremediation of Hypnales aquatic mosses has been poorly investigated compared to aquatic macrophytes. Their potential is usually indicated as a tool for bioindication and environmental monitoring more than for pollutant removal. When phytoremediation has been considered, insufficient attention has been paid to the adaptability of biomasses to different needs. In this study the heavy metal uptake of moss Taxiphyllum barbieri grown in two different light conditions, was tested with high concentrations of elements such as Pb, Cd, Zn, Cu, As, and Cr. This moss produces dense mats with few culture needs. The experimental design confirmed the capacity of the moss to accumulate HMs accordingly to their physiology and then demonstrated that a significant proportion of HMs was accumulated within a few hours. In addition to the biosorption effect, an evident contribution of the active simplistic mass can be evidenced. These reports of HM accumulation within short time intervals, show how this moss is particularly suitable as an adaptable bio-filter, representing a new opportunity for water eco-sustainable remediation.

scholarly journals Seabird diets as bioindicators of Atlantic herring recruitment and stock size: a new tool for ecosystem-based fisheries management

2018 ◽  
Vol 75 (8) ◽  
pp. 1215-1229 ◽  
Author(s):  
Lauren C. Scopel ◽  
Antony W. Diamond ◽  
Stephen W. Kress ◽  
Adrian R. Hards ◽  
Paula Shannon
Keyword(s):  
Fishery Management ◽  
Gulf Of Maine ◽  
Clupea Harengus ◽  
Data Series ◽  
Atlantic Herring ◽  
Stock Biomass ◽  
Stock Assessments ◽  
Spawning Stock ◽  
Fishery Data ◽  
Ecosystem Based Fisheries Management

Ecosystem-based fishery management requires understanding of relationships between exploited fish and their predators, such as seabirds. We used exploratory regression analyses to model relationships between Atlantic herring (Clupea harengus) in the diet of seabird chicks at nine nesting colonies in the Gulf of Maine and four types of fishery- and survey-derived herring data. We found several strong relationships, which suggests spatial structuring in herring stocks and likely patterns of herring movements before they recruit into the fishery. Some types of herring data seldom used in stock assessments — notably acoustic surveys, fixed-gear landings, and mass-at-age (i.e., weight-at-age) — correlated as strongly with seabird data as more commonly used series, such as mobile-gear landings and modeled spawning stock biomass. Seabird chick diets collected at specific locations thus offer a promising means to assess the size, distribution, and abundance of juvenile herring across a broad area prior to recruitment, which is a major source of uncertainty in fisheries. Common terns (Sterna hirundo) showed the most potential as a bioindicator, correlating well and showing consistent spatial patterns with 11 of 13 fishery data series.

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