Identification of Spring- and Autumn-Spawning Herring (Clupea harengus harengus) using Maturity Stages Assigned from a Gonadosomatic Index Model

A model is developed to identify the spawning type of individual herring (Clupea harengus harengus) from the sympatric spring and autumn spawning stocks in the southern Gulf of St. Lawrence (NAFO Division 4T). The maturity stage is assigned from a gonadosomatic index model using discriminant analysis and the spawning type is determined from the maturity stage and the month of capture according to a detailed description of the annual maturity cycle of each type. The model is shown to be objective, quantitative, and precise. Greater than 97% overall agreement was achieved between the spawning type classification of individuals by histological means and by the model, significantly improving the identification accuracy compared with a macroscopic maturity stage key. The model also has the advantages of (1) identifying the spawning type directly by determining the "season of spawning" rather than the "season spawned" as is inferred from indirect evidence such as otolith characteristics or meristic data, (2) requiring easily obtained, quantifiable data, and (3) enabling the rapid treatment of a large number of specimens.

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

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f87-166 ◽

1987 ◽

Vol 44 (7) ◽

pp. 1379-1385 ◽

Cited By ~ 4

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.

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

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s002531541100018x ◽

2011 ◽

Vol 91 (7) ◽

pp. 1477-1487 ◽

Cited By ~ 12

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.

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Decision tree analysis for the determination of relevant variables and quantifiable reference points to establish maturity stages in Enteroctopus megalocyathus and Illex argentinus

ICES Journal of Marine Science ◽

10.1093/icesjms/fsu202 ◽

2015 ◽

Vol 72 (5) ◽

pp. 1449-1461 ◽

Cited By ~ 2

Author(s):

Augusto César Crespi-Abril ◽

Nicolás Ortiz ◽

David Edgardo Galván

Keyword(s):

Decision Tree ◽

Gonadosomatic Index ◽

Reference Points ◽

Maturity Stage ◽

Maturity Stages ◽

Terminal Organ ◽

Nidamental Gland ◽

Relevant Variables ◽

Illex Argentinus

Abstract Determining the maturity condition of a large number of individuals is crucial for stock assessment and management of cephalopod populations, but this task is difficult to conduct in practice. We propose a novel approach for maturity stage classification using observer-independent criteria. Relevant morphological variables for classification are determined via decision tree (DT) analysis. Using Illex argentinus and Enteroctopus megalocyathus as case studies, individuals were sexed and assigned to a maturity stage defined by specific macroscopic maturity scales. Also, for each individual, the weight of the gonad, accessory glands/ducts, mantle length, and total weight were recorded and maturity indices were calculated (Hayashi index and gonadosomatic index). Two different DT models were fitted: one considering all maturity stages and the other considering only intermediate maturity stages since these are the most difficult to determine in practice. For the classification of I. argentinus among all stages, the weights of the nidamental gland and oviducts were the most relevant variables for females (misclassification 23%), while spermatophoric complex and testis weights were the key variables for males (misclassification 23%). For classification of intermediate stages only, the nidamental gland and spermatophoric complex weights were the most relevant variables to classify females (misclassification 19%) and males (misclassification 21%), respectively. For E. megalocyathus, the oviducts and ovary weights of females and the terminal organ weight of males were the most relevant variables for classification among all maturity stages (misclassification 16% and 18%, respectively). For intermediate maturity stages, the same variables were most important and misclassification improved to 13% for both sexes. Gonadosomatic and Hayashi's indices were not relevant in either model. DTs based on measurements of cephalopod reproductive systems revealed a simple classification system for maturity stages using only a few variables that are easy to measure in the field and are independent of observer training.

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Automatic Grain Type Classification of Snow Micro Penetrometer Signals With Random Forests

IEEE Transactions on Geoscience and Remote Sensing ◽

10.1109/tgrs.2012.2220549 ◽

2013 ◽

Vol 51 (6) ◽

pp. 3328-3335 ◽

Cited By ~ 15

Author(s):

Scott Havens ◽

Hans-Peter Marshall ◽

Christine Pielmeier ◽

Kelly Elder

Keyword(s):

Random Forests ◽

Type Classification

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Interaction Between Stock Area, Stock Abundance, and Catchability Coefficient

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f85-124 ◽

1985 ◽

Vol 42 (5) ◽

pp. 989-998 ◽

Cited By ~ 87

Author(s):

G. H. Winters ◽

J. P. Wheeler

Keyword(s):

Stock Assessment ◽

Population Decline ◽

Clupea Harengus ◽

Atlantic Herring ◽

Population Abundance ◽

Commercial Catch ◽

Standard Manner ◽

Clupea Harengus Harengus ◽

The Relationship ◽

Stock Abundance

The relationship between commercial catch-rates and population density upon which many stock assessment models depend assumes that stock area (A) is constant and independent of population abundance. Starting from a theoretical demonstration that the catchability coefficient (q) is inversely proportional to A, we establish the empirical basis of this relationship through comparisons of q and A of various Northwest Atlantic herring (Clupea harengus harengus) stocks and, in more detail, for Fortune Bay herring. For these stocks the relationship was of the form q = cA−b. For Atlantic herring stocks, levels of b were in excess of 0.80. In Fortune Bay herring, reductions in abundance were accompanied by proportional reductions in A, which in turn was inversely correlated with changes in q. School size, measured as catch per set, also declined as population levels declined but the change was not proportional. Published findings indicate that pelagic stocks in particular, and fish stocks in general, exhibit a common response of reductions in A with interactive increases in the q during periods of rapid population decline. We conclude that the conventional assumption of a constant stock area is usually violated due to the systematic interaction between A and population abundance which is reflected in an inverse relationship between stock abundance and q. Calibration of sequential population models should therefore be restricted to research vessel data collected in a standard manner and covering the distributional area of the stock.

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Ultrastructural Studies of Piscine Erythrocytic Necrosis (PEN) in Atlantic Herring (Clupea harengus harengus)

Journal of the Fisheries Research Board of Canada ◽

10.1139/f78-022 ◽

1978 ◽

Vol 35 (1) ◽

pp. 148-154 ◽

Cited By ~ 23

Author(s):

Paul W. Reno ◽

Marie Philippon-Fried ◽

Bruce L. Nicholson ◽

Stuart W. Sherburne

Keyword(s):

Electron Microscope ◽

Key Words ◽

Clupea Harengus ◽

Type I ◽

Atlantic Herring ◽

Type Ii ◽

Inclusion Type ◽

Cytoplasmic Inclusions ◽

Ultrastructural Studies ◽

Clupea Harengus Harengus

Erythrocytes of PEN-positive Atlantic herring (Clupea harengus harengus) were examined to determine their ultrastructure. Cytoplasmic inclusions were of two types when observed under the electron microscope. The first type (type I) appeared coarsely granular, electron dense, round, and up to 1.5 μm in diameter. Virions were closely associated with this type of inclusion. The second type of inclusion (type II) had approximately the same appearance as the surrounding cytoplasm, from which it was separated by a discrete membrane, and was variable in size. Virions were not intimately associated with type II inclusions. Virions occurred singly or in clusters within the cytoplasm or in association with type I inclusions and were hexagonal and 145 nm in diameter. Virions were composed of a rigid hexagonal capsid 8 nm wide, a lighter 16-nm region, and a core 100 nm in diameter. The virus of PEN is presumptively classified as an Iridovirus. Key words: ultrastructure, erythrocytes, virology

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Direct and Indirect Estimation of Gillnet Selection Curves of Atlantic Herring (Clupea harengus harengus)

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f90-050 ◽

1990 ◽

Vol 47 (3) ◽

pp. 460-470 ◽

Cited By ~ 17

Author(s):

G. H. Winters ◽

J. P. Wheeler

Keyword(s):

Selection Criterion ◽

Mesh Size ◽

Clupea Harengus ◽

Atlantic Herring ◽

Population Parameters ◽

Composition Data ◽

Catch Data ◽

Specific Selectivity ◽

Acoustic Surveys ◽

Clupea Harengus Harengus

Length-specific selection curves for Atlantic herring (Clupea harengus) were calculated for a series of gillnets ranging in mesh size from 50.8 to 76.2 mm (stretched measure) using Holt's (1963) model (ICNAF Spec. Publ. 5: 106–115). These curves were than compared with direct estimates of length-specific selectivity obtained from a comparison of gillnet catch length frequencies with population length composition data as determined from acoustic surveys. Selection curves calculated indirectly using the Holt model were unimodal and congruent. The empirical selection curves however were multimodal and fishing power varied with mesh size. These differences in selectivities were due to the fact that herring were caught not only by wedging at the maximum girth but also at other body positions such as the gills and snout. Each of these modes of capture have different length-specific selectivity characteristics and, since the relative contributions of the different modes of capture varied both between nets and annually, the selection curve of herring for a particular mesh size is not unique. It can however be reasonably approximated when girth is used as the selection criterion. Direct empirical selectivities are therefore recommended when interpreting population parameters from herring gillnet catch data.

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Large-scale unsupervised clustering of Orca vocalizations: a model for describing orca communication systems

10.7287/peerj.preprints.27979v1 ◽

2019 ◽

Author(s):

Marion Poupard ◽

Paul Best ◽

Jan Schlüter ◽

Helena Symonds ◽

Paul Spong ◽

...

Keyword(s):

Communication Systems ◽

Large Scale ◽

Pitch Contour ◽

Call Type ◽

Recording Station ◽

The Face ◽

Multichannel Recordings ◽

Type Classification ◽

Anthropic Pressure

Killer whales (Orcinus orca) can produce 3 types of signals: clicks, whistles and vocalizations. This study focuses on Orca vocalizations from northern Vancouver Island (Hanson Island) where the NGO Orcalab developed a multi-hydrophone recording station to study Orcas. The acoustic station is composed of 5 hydrophones and extends over 50 km 2 of ocean. Since 2015 we are continuously streaming the hydrophone signals to our laboratory in Toulon, France, yielding nearly 50 TB of synchronous multichannel recordings. In previous work, we trained a Convolutional Neural Network (CNN) to detect Orca vocalizations, using transfer learning from a bird activity dataset. Here, for each detected vocalization, we estimate the pitch contour (fundamental frequency). Finally, we cluster vocalizations by features describing the pitch contour. While preliminary, our results demonstrate a possible route towards automatic Orca call type classification. Furthermore, they can be linked to the presence of particular Orca pods in the area according to the classification of their call types. A large-scale call type classification would allow new insights on phonotactics and ethoacoustics of endangered Orca populations in the face of increasing anthropic pressure.

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