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.

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.

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

Habitat use by early life stages of the re-established striped bass and conspecific fish species along the St. Lawrence estuary

2020 ◽  
Vol 237 ◽  
pp. 106696
Author(s):  
L. Vanalderweireldt ◽  
G. Winkler ◽  
E.L. Forget-Lacoursière ◽  
M. Mingelbier ◽  
P. Sirois
Keyword(s):  
Habitat Use ◽  
Striped Bass ◽  
Fish Species ◽  
Early Life ◽  
Life Stages ◽  
Early Life Stages ◽  
Lawrence Estuary ◽  
St Lawrence Estuary

Estimates of the Theoretical Biomass of Juvenile Winter Flounder, Pseudopleuronectes americanus (Walbaum) Required for a Fishery in Rhode Island

1965 ◽  
Vol 22 (4) ◽  
pp. 945-954 ◽  
Author(s):  
Saul B. Saila ◽  
Donald B. Horton ◽  
Richard J. Berry
Keyword(s):  
Life History ◽  
Rhode Island ◽  
Significant Proportion ◽  
Early Life History ◽  
Vital Statistics ◽  
Winter Flounder ◽  
Pseudopleuronectes Americanus ◽  
Empirical Estimates ◽  
Equilibrium Yield ◽  
History Of

A model of the life history of the winter flounder was constructed using empirical estimates of vital statistics. The initial stock weight of juveniles was determined by substituting trial initial stock weight values into equations which contained average values of growth and mortality coefficients until the observed value of the equilibrium yield was approximated. Model data indicated that the stock weight of juvenile winter flounder at an age of 5 months constituted a significant proportion of the equilibrium yield even with conservative estimates of model coefficients. Growth appeared to be sufficiently rapid during early life-history stages to provide for a large increase in biomass in spite of considerable natural mortality.

scholarly journals Quantitative molecular detection of larval Atlantic herring (Clupea harengus) in stomach contents of Atlantic mackerel (Scomber scombrus) marks regions of predation pressure

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Bridie Jean Marie Allan ◽  
Jessica Louise Ray ◽  
Maik Tiedemann ◽  
Valeriya Komyakova ◽  
Frode Vikebø ◽  
...  
Keyword(s):  
Early Life ◽  
Molecular Detection ◽  
Stomach Contents ◽  
Early Life History ◽  
Predation Pressure ◽  
Clupea Harengus ◽  
Atlantic Herring ◽  
Atlantic Mackerel ◽  
Life History Stages ◽  
Scomber Scombrus

AbstractMortality rates in the early life-history stages of fishes are generally high yet identifying the causes remain unclear. Faltering recruitment rates of Atlantic herring (Clupea harengus) in the Norwegian Sea indicate a need to identify which mortality factors influence larval herring survival. Previous research suggests that increased predation pressure by Atlantic mackerel (Scomber scombrus) may contribute to the disconnect between spawning stock biomass and recruitment. To quantify the contribution of predation pressure by Atlantic mackerel to herring larval mortality, two research cruises were conducted within a probable “hot spot” (67–72° N) for intensified mackerel predation based on particle drift simulations. Mackerel stomach contents were analysed for herring larvae content using droplet digital polymerase chain reaction (ddPCR) with a quantitative molecular detection assay specific for herring. The ddPCR results demonstrate clear predation by mackerel on herring larvae and also suggest that the alternative use of visual examination may give misleading results. Our results show that mackerel should be considered a potentially important predator on herring larvae. The quantitative molecular assay presented here shows great promise as an efficient and specific tool to correctly identify and quantify predation pressure on early life-history stages of fishes.

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