Spawning Dynamics of Golf of St. Lawrence Herring (Clupea harengus)

1989 ◽  
Vol 46 (12) ◽  
pp. 2085-2094 ◽  
Author(s):  
Timothy C. Lambert ◽  
Shoukry N. Messieh
Keyword(s):  
Stock Assessment ◽  
Sampling Procedure ◽  
Clupea Harengus ◽  
Spawning Season ◽  
Biological Information ◽  
Age Classes ◽  
Spawning Grounds

Mean day of arrival of spawning herring (Clupea harengus) in the Gulf of St. Lawrence was calculated for different length groups by region and season. During the spawning season of both spring and autumn groups, herring arrived and deposited eggs on spawning grounds in decreasing order of age and length. Spawning bed surveys at two locations confirmed batch depositions of eggs which were correlated with the presence of dominant age-classes within the spawning population. Due to limitations of the port sampling procedure for collection of biological information routinely used in herring stock assessment, some length groups were underrepresented. This could result in the underestimation of the abundance of recruiting year-classes.

Estimating the dynamics of spawning aggregations using biological and fisheries data

2016 ◽  
Vol 67 (3) ◽  
pp. 342 ◽  
Author(s):  
André E. Punt ◽  
David C. Smith ◽  
Malcolm Haddon ◽  
Sarah Russell ◽  
Geoffrey N. Tuck ◽  
...  
Keyword(s):  
Stock Assessment ◽  
Spawning Season ◽  
Turnover Rates ◽  
Spawning Grounds ◽  
Arrival Times ◽  
Spawning Aggregations ◽  
Average Proportion ◽  
Acoustic Surveys ◽  
Males And Females ◽  
Spawning Biomass

Acoustic surveys can provide accurate estimates of biomass at a particular location at a point in time, but provide a negatively biased estimate of the total spawning population unless the proportion of fish that are unavailable to the survey is accounted for. Changes to the ages and maturity stages of fish caught during the spawning season is evidence for turnover of fish during spawning and, along with information on relative abundance, provides a basis for estimating turnover rates. A model is therefore developed that tracks the numbers of males and females by age as they arrive on the spawning grounds, initiate spawning, complete spawning and leave the spawning grounds. This model can be used to determine the proportion of the spawning biomass on the spawning grounds over the spawning season. It is applied to data for blue grenadier, Macruronus novaezelandiae, off western Tasmania, Australia. The results can be used to estimate the average proportion of the population available to an acoustic survey, although this estimate is not likely to be very precise, owing to the high between-year variation in arrival times. However, the model provides a quantitative estimate of turnover rate that was previously not available, and is a rigorous basis for estimating turnover for stock assessment.

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.

The location of spawning of Irish Sea herring (Clupea harengus)

2001 ◽  
Vol 81 (4) ◽  
pp. 713-714 ◽  
Author(s):  
Mark Dickey-Collas ◽  
Richard D.M. Nash ◽  
Juan Brown
Keyword(s):  
Time Series ◽  
Clupea Harengus ◽  
Irish Sea ◽  
Spawning Grounds ◽  
Isle Of Man ◽  
The North

Time series of ichthyoplankton surveys targeted at herring larvae describe the distribution of spawning in the north Irish Sea by mapping the occurrence of very young larvae. The surveys suggest, that like other herring stocks, the spawning grounds of Irish Sea herring vary over the years. Currently, spawning at the Mourne location is greatly reduced whereas spawning has occurred at a newly described site to the north of the Isle of Man (off the Point of Ayre). Whilst spawning is dominated by autumn spawners in late September, some spawning occurs through to January.

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.

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.

scholarly journals Feeding of mature cod (Gadus morhua) on the spawning grounds in Lofoten

2008 ◽  
Vol 65 (4) ◽  
pp. 571-580 ◽  
Author(s):  
Kathrine Michalsen ◽  
Edda Johannesen ◽  
Bjarte Bogstad
Keyword(s):  
Diet Composition ◽  
Gadus Morhua ◽  
Barents Sea ◽  
Lower Proportion ◽  
Clupea Harengus ◽  
Stomach Fullness ◽  
Spawning Grounds ◽  
Spawning Period ◽  
Established Fact ◽  
A Minor

Abstract Michalsen, K., Johannesen, E., and Bogstad, B. 2008. Feeding of mature cod (Gadus morhua) on the spawning grounds in Lofoten. – ICES Journal of Marine Science, 65: 571–580. Many authors state that cod (Gadus morhua) do not feed during the spawning period. However, this more or less established fact has rarely been investigated in the field. Here, the content of stomachs from Northeast Arctic cod (NEAC) and Norwegian coastal cod (NCC) sampled from the spawning ground in Lofoten were examined over a 10-year period (1996–2006). The occurrence of food in the stomachs of spawning cod, stomach fullness, diet composition, and variation in these variables between NEAC and NCC, year, and sex were analysed and compared. The analysis shows that cod do feed, even when they are in a spawning state. NCC had a lower proportion of empty stomachs and the stomachs were fuller than those from NEAC. Females had a lower proportion of empty stomachs than males and their stomachs were in general fuller. Herring (Clupea harengus) dominated the diet of cod. However, cod consumption of herring on the spawning grounds seems to be a minor source of mortality on herring. Although spawning cod do feed, the proportion of empty stomachs was higher and stomach fullness was lower than in stomachs of NEAC from the Barents Sea.

A multifrequency method to classify and evaluate fisheries acoustics data

2006 ◽  
Vol 63 (10) ◽  
pp. 2225-2235 ◽  
Author(s):  
J Michael Jech ◽  
William L Michaels
Keyword(s):  
Clupea Harengus ◽  
Biological Information ◽  
Classification Algorithms ◽  
Atlantic Herring ◽  
Population Abundance ◽  
Acoustic Data ◽  
Video Images ◽  
Abundance Estimates ◽  
Fisheries Acoustics ◽  
Acoustic Surveys

Acoustic surveys have been conducted on Georges Bank from 1998 to present to estimate Atlantic herring (Clupea harengus) population abundance. Acoustic data were collected with a 12 or 18, 38, and 120 kHz Simrad EK500 scientific echo sounder. A pelagic trawl and underwater video images were used to collect biological information and to verify the species composition of acoustic backscatter. A multifrequency classification method was developed to improve the efficiency and accuracy of classifying species from acoustic echograms. In this method, a volume backscatter (Sv) threshold was applied equivalently to all echograms, and then a composite echogram was created based on which frequencies had Sv greater than or less than the Sv threshold. The results of this method were compared with the standard method of visually scrutinizing regions, and metrics were developed to evaluate the accuracy of classification algorithms relative to current methods, as well as to assess the effects of classification methods on population abundance estimates. In general, this method matched visually scrutinized Atlantic herring regions, but with consistent biases in classifying 38 kHz backscatter. The metrics highlighted spatial and temporal changes in the acoustic landscape, which may be indicative of intra- and inter-annual biological changes.

scholarly journals Long-term stability in modelled zooplankton influx could uphold major fish spawning grounds on the Norwegian continental shelf

2016 ◽  
Vol 73 (2) ◽  
pp. 189-196 ◽  
Author(s):  
Anders Frugård Opdal ◽  
Frode B. Vikebø
Keyword(s):  
Continental Shelf ◽  
Gadus Morhua ◽  
Fish Larvae ◽  
Ocean Model ◽  
Clupea Harengus ◽  
Calanus Finmarchicus ◽  
Crustacean Zooplankton ◽  
Spawning Grounds ◽  
Fish Spawning ◽  
Norwegian Continental Shelf

Early life stages of fish spawned on the Norwegian continental shelf have long been suggested to depend on eggs and nauplii from the crustacean zooplankton Calanus finmarchicus for survival. Calanus finmarchicus overwinters in the deep basins of the Norwegian Sea, and gravid females must be advected onto the shelf prior to spawning if eggs and nauplii larvae are to serve as food for fish larvae. In this study, cross-shelf advection of C. finmarchicus is simulated over 52 years (1960–2011) using a numerical ocean model coupled with an individual-based model. The results suggest that cross-shelf transport of C. finmarchicus is surprisingly stable across years and that transport is particularly concentrated immediately upstream of the two major spawning areas for the Northeast Arctic cod (Gadus morhua) and the Norwegian spring-spawning herring (Clupea harengus), namely Lofoten and Møre, respectively. Two large topographical features, the Træna Trough and the Norwegian Trench, appear to be funnelling C. finmarchicus onto the shelf in these two areas. This could suggest that the fish spawning grounds outside Møre and Lofoten are, in part, maintained owing to stable interannual food supply in spring.

scholarly journals Histological analysis invalidates macroscopically determined maturity ogives of the Kattegat cod (Gadus morhua) and suggests new proxies for estimating maturity status of individual fish

2006 ◽  
Vol 63 (3) ◽  
pp. 485-492 ◽  
Author(s):  
F. Vitale ◽  
H. Svedäng ◽  
M. Cardinale
Keyword(s):  
Gadus Morhua ◽  
Histological Analysis ◽  
Spawning Season ◽  
Age Classes ◽  
Data Set ◽  
Histological Techniques ◽  
Stock Biomass ◽  
Spawning Stock ◽  
Correct Estimation ◽  
Spawning Biomass

Abstract Assessment and management of fish populations currently rely on correct estimation of the spawning-stock biomass (SSB), which is based on accurate maturity ogives of the population. Although maturity ogives are usually calculated through macroscopic evaluation of the gonads, histology is generally considered to be more accurate. Here we show that the macroscopic analysis consistently overestimates the proportion of mature females for all age classes in Kattegat cod. The resulting bias showed minimum values for all age classes about a month before the spawning season. Consequently, estimation of the incidence of maturation in females several months before or after the spawning season can only be accurate using histological techniques. Further, the observed bias was used to reconstruct a historical data set of maturity ogives of Kattegat cod. The results showed that female spawning biomass (FSB) might have been overestimated by up to 35%. However, as histological analysis is considered a laborious procedure, proxies of maturity status were sought. It was indicated that the gonadosomatic and hepatosomatic indices may serve as robust proxies for discriminating mature females from immature, thus greatly enhancing the accuracy of the macroscopic maturity evaluation of cod gonads when histological analysis is lacking.

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