Séparation des populations de hareng de l'Atlantique (Clupea harengus harengus) de l'estuaire du Saint-Laurent et de la péninsule gaspésienne

1980 ◽  
Vol 37 (1) ◽  
pp. 66-71 ◽  
Author(s):  
G. Côté ◽  
P. Lamoureux ◽  
J. Boulva ◽  
G. Lacroix
Keyword(s):  
Clupea Harengus ◽  
Atlantic Herring ◽  
Morphometric Characteristics ◽  
Lawrence Estuary ◽  
Clupea Harengus Harengus ◽  
St Lawrence Estuary ◽  
Gaspe Peninsula ◽  
Gaspé Peninsula

Examination of morphometric and meristic characteristics of Atlantic herring (Clupea harengus harengus) caught during spawning along the Gaspé coast and the St. Lawrence Estuary lead to the conclusion of the existence of at least three herring populations in that area. The first one occurs in the St. Lawrence Estuary, spawns in the spring and is characterized by smaller length-at-age values than the two other populations which are comprised respectively of spring-spawners and autumn-spawners that are fished off the Gaspé peninsula.Key words: Atlantic herring, St. Lawrence Estuary, Gaspé peninsula, morphometric characteristics, meristic characteristics

Régime alimentaire et principaux facteurs influençant l'alimentation des larves de capelan (Mallotus villosus), d'éperlan (Osmerus mordax) et de hareng (Clupea harengus harengus) dans un estuaire partiellement mélangé

1986 ◽  
Vol 43 (5) ◽  
pp. 968-979 ◽  
Author(s):  
R. Courtois ◽  
J. J. Dodson
Keyword(s):  
Feeding Rate ◽  
Water Masses ◽  
Clupea Harengus ◽  
Gut Contents ◽  
Osmerus Mordax ◽  
Lawrence Estuary ◽  
Daily Cycles ◽  
Food And Feeding ◽  
Clupea Harengus Harengus ◽  
St Lawrence Estuary

The food and feeding rate periodicity of larvae of capelin (Mallotus villiosus), smelt (Osmerus mordax), and herring (Clupea harengus harengus) were studied to determine the existence of potential interactions between the larvae of these three species. Analyses of the gut contents showed that larvae of capelin started to feed before yolk sac absorption but that the feeding rate was low (<20%) in the lower St. Lawrence estuary; the small size of capelin larvae restricted their feeding to tintinnids. Larvae of the two other species feed at a greater rate than capelin larvae and their food is more diverse. The temporal sequence of feeding incidences showed daily cycles for the three species and semidiurnal cycles for larvae of capelin and herring. The importance of light for feeding of larvae was confirmed by the daily cycles and by the greater abundance of larvae with gut contents in surface waters (0–20 m). From the absence of a relation between biotic factors (density of larvae) and the temporal evolution of feeding incidences, we suggest that semidiurnal cycles are mainly related to temperature changes associated with advection of water masses at the sampling stations. Even though similar reactions to certain environmental variables were observed, we concluded that interspecific competition is minimal between larvae of the three species. Although present at the same stations, larvae of different species mainly occurred in distinct water masses; they are also mainly of different size. Those characteristics force them to exploit organisms of different size and mainly of different species.

Spatial Configurations of Young Herring (Clupea harengus harengus) larvae in the St. Lawrence Estuary: Importance of Biological and Physical Factors

1985 ◽  
Vol 42 (S1) ◽  
pp. s91-s104 ◽  
Author(s):  
M. Henri ◽  
J. J. Dodson ◽  
H. Powles
Keyword(s):  
Specific Gravity ◽  
Water Column ◽  
Gravity Current ◽  
Yolk Sac ◽  
Clupea Harengus ◽  
Physical Factors ◽  
Residual Circulation ◽  
Lawrence Estuary ◽  
Clupea Harengus Harengus ◽  
St Lawrence Estuary

The phenomenon of larval retention has recently been identified as central to the structuring of herring stocks. It has been shown that retention of larval fish populations in estuaries is dependent on active vertical migration, the capacity for which develops with growth, but the present study shows that mechanisms for spatial structuring of larval herring (Clupea harengus harengus) populations act at the earliest (yolk sac and post-yolk sac) stages. The study was carried out on the Isle-Verte stock of the St. Lawrence estuary in 1981 and 1982. Length–frequencies and tide-related abundance fluctuations suggested that larvae are retained in the study area. As a result, larvae remain aggregated throughout the sampling period of approximately 1 mo. Yolk sac larvae were significantly more abundant near the bottom than in the water column, while post-yolk sac larvae were significantly less abundant in the suprabenthic layer than in the water column. Larvae, being negatively buoyant, tend to sink in slack water but are transported upwards by turbulence resulting from tidal flows. The extent of vertical transport of larvae in the water column is greatest for larvae with lesser specific gravities; specific gravity is at a maximum at hatching and decreases to a minimum at yolk sac absorption. We conclude that larval specific gravity, current velocity, and the two-layer residual circulation are the major factors causing retention and aggregation of larvae.

Nearshore Ichthyoplankton of a North Temperate Estuary

1984 ◽  
Vol 41 (11) ◽  
pp. 1653-1663 ◽  
Author(s):  
H. Powles ◽  
F. Auger ◽  
G. J. FitzGerald
Keyword(s):  
Early Life ◽  
Early Life History ◽  
Clupea Harengus ◽  
Winter Flounder ◽  
Nearshore Zone ◽  
Pseudopleuronectes Americanus ◽  
Lawrence Estuary ◽  
Clupea Harengus Harengus ◽  
St Lawrence Estuary ◽  
Spawning Biomass

Composition of ichthyoplankton in the nearshore zone (0–6 km from shore) of the St. Lawrence estuary showed important differences from that farther offshore. In particular, larvae of herring (Clupea harengus harengus), winter flounder (Pseudopleuronectes americanus), and smooth flounder (Liopsetta putnami) made up a greater proportion of the ichthyoplankton than in published surveys farther offshore. Peak catches of larval herring were 1–2 orders of magnitude higher than in offshore waters. Winter flounder and smooth flounder larvae were significantly more abundant [Formula: see text] from shore than 1–6 km offshore; significant abundance gradients were not found for other species. Nearshore areas have received considerably less effort than offshore areas in earlier studies, and we suggest that more intensive studies in the nearshore zone, at least for those species mentioned, would be of importance for elucidating early life history processes and for estimating spawning biomass based on ichthyoplankton surveys.

Interaction Between Stock Area, Stock Abundance, and Catchability Coefficient

1985 ◽  
Vol 42 (5) ◽  
pp. 989-998 ◽  
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.

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

1978 ◽  
Vol 35 (1) ◽  
pp. 148-154 ◽  
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

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

1990 ◽  
Vol 47 (3) ◽  
pp. 460-470 ◽  
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.

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.

Isolation and characterization of antifreeze proteins from smelt (Osmerus mordax) and Atlantic herring (Clupea harengus harengus)

1990 ◽  
Vol 68 (8) ◽  
pp. 1652-1658 ◽  
Author(s):  
K. Vanya Ewart ◽  
Garth L. Fletcher
Keyword(s):  
Antifreeze Proteins ◽  
Gel Filtration ◽  
Exchange Chromatography ◽  
Clupea Harengus ◽  
Osmerus Mordax ◽  
Atlantic Herring ◽  
Activity Levels ◽  
Isolation And Characterization ◽  
Sea Raven ◽  
Clupea Harengus Harengus

Antifreeze proteins (AFPs) from smelt (Osmerus mordax) and Atlantic herring (Clupea harengus harengus) were isolated using gel filtration, ion exchange chromatography, and high performance liquid chromatography. The AFPs of smelt appeared to consist of at least six components and those of Atlantic herring, of at least two components. The relative molecular masses of these antifreezes were 24 000 and 14 600, respectively. Amino acid analysis showed both proteins to be cystine-rich, type II AFPs like those of the sea raven (Hemitripterus americanus). In addition, smelt AFPs were found to be immunologically similar to those of the sea raven. The smelt AFPs differed from those of Atlantic herring and sea raven in that they contained a small amount of glucosamine (~3%). The activity levels of the smelt and herring AFPs were reduced in the presence of dithiothreitol, indicating the functional importance of intact disulfide bonds.

Maturation and Spawning of Atlantic Herring (Clupea harengus harengus) in the Southern Gulf of St. Lawrence

1975 ◽  
Vol 32 (1) ◽  
pp. 66-68 ◽  
Author(s):  
S. N. Messieh
Keyword(s):  
Clupea Harengus ◽  
Atlantic Herring ◽  
Spawning Grounds ◽  
Nursery Areas ◽  
Maturity Stages ◽  
Clupea Harengus Harengus

Analysis of maturity stages of herring samples taken from the southern Gulf of St. Lawrence shows two maturation cycles for spring and autumn spawning herring. The spring population has a spawning peak in May and the summer–autumn population extends spawning from July through September. Spawning grounds of spring and autumn herring populations and their nursery areas are mapped.

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