A new ageing method for eggs of fish species with daily spawning synchronicity

2001 ◽  
Vol 58 (12) ◽  
pp. 2330-2340 ◽  
Author(s):  
M Bernal ◽  
D L Borchers ◽  
L Valdés ◽  
A Lago de Lanzós ◽  
S T Buckland
Keyword(s):  
Egg Production ◽  
Production Method ◽  
Biological Information ◽  
Northern Spain ◽  
Egg Development ◽  
Spawning Period ◽  
Spawning Frequency ◽  
Resampling Method ◽  
Daily Spawning ◽  
Ageing Methods

A new method for ageing staged eggs of fish is presented. The method is intended for species that show spawning synchronicity and for which the egg phase can be classified into development stages, each of which lasts less than a day, such as sardines and anchovies. It combines biological information on the daily frequency of spawning and egg development rates, via a probabilistic resampling method. A general methodology that allows the use of models of daily spawning frequency and egg development as a function of temperature is provided and applied to sardine egg data from three surveys in northern Spain. Unlike previous ageing methods, the proposed method allows for the variability of egg ages in a way that reflects the extent of the assumed daily spawning period, and estimates of the uncertainty in the stage-to-age conversion can be obtained. These estimates of uncertainty can be incorporated into subsequent analyses that involve age as a covariate, such as in the daily egg production method (DEPM), thus allowing more reliable estimates of the variance of egg production.

scholarly journals Atlantic mackerel daily spawning dynamics and implications for batch fecundity estimations

2018 ◽  
Vol 75 (5) ◽  
pp. 1647-1654
Author(s):  
K Ganias ◽  
D Marmara ◽  
A Solla ◽  
D Garabana ◽  
R Dominguez-Petit
Keyword(s):  
Egg Production ◽  
Time Window ◽  
Production Method ◽  
Time Of Day ◽  
Batch Fecundity ◽  
Atlantic Mackerel ◽  
Spawning Frequency ◽  
Scomber Scombrus ◽  
Daily Spawning

Abstract The present study contributes to a better understanding of the daily spawning dynamics of southern NEA mackerel (Scomber scombrus) with implications for the estimation of batch fecundity. It shows that there is a time window during the day, mainly in the afternoon, during which the advanced oocyte mode in imminent spawners separates from the remaining, smaller oocytes. This synchronicity in the separation of the spawning batch amongst imminent spawners corroborates evidence for the existence of daily spawning synchronicity in the population. This is particularly important for applications of the daily egg production method, DEPM, because such pattern facilitates both the ageing of eggs for the estimation of the daily egg production at sea and the ageing of postovulatory follicles for the estimation of spawning frequency. For NEA mackerel, batch fecundity could only be measured when a clear hiatus was established between the spawning batch and the smaller oocytes. Hydrated females that do not show such hiatus would not be valid for batch fecundity measurements suggesting that the “hydrated oocytes method” is not fully applicable for this stock. Knowing the time of day at which the batch is separated, will facilitate the sampling of valid females for the estimation of batch fecundity.

Spawning biomass of Argentine anchovy (Engraulis anchoita) from 1996 to 2004 using the Daily Egg Production Method

2008 ◽  
Vol 89 (4) ◽  
pp. 829-837 ◽  
Author(s):  
Marcelo Pájaro ◽  
Gustavo J. Macchi ◽  
Ezequiel Leonarduzzi ◽  
Jorge E. Hansen
Keyword(s):  
Regional Differences ◽  
Egg Production ◽  
Basic Research ◽  
Production Method ◽  
Mean Values ◽  
Spawning Frequency ◽  
Spawning Stock ◽  
The Mean ◽  
Annual Means ◽  
Spawning Biomass

The Daily Egg Production Method (DEPM) was used to compute spawning biomass of Engraulis anchoita off Argentina. Estimates of the daily egg production (P0) for the northern stock ranged from 594 to 936 eggs m−2, whereas the annual means of the Patagonian stock ranged from 185 to 605 eggs m−2. The mean values estimated for the Argentine anchovy DEPM parameters were characterized by inter-annual differences greater than inter-regional differences with the exception of P0. For the northern population, the estimates of mean weight of mature females ranged from 15 to 26 g, the relative batch fecundity from 414 to 600 eggs g−1, the spawning frequency (S) from 0.078 to 0.179, and the females ratio from 0.519 to 0.622 of the spawning stock. The estimates corresponding to the Patagonian stock were similar being 15 to 24 g, 418 to 583 eggs g−1, 0.079 to 0.244, and 0.394 to 0.590, respectively. The annual estimates of the spawning biomass for the northern and Patagonian populations ranged between 1.6–3.5 and 0.3–1.5 million metric tons, respectively. A weakness in the application of DEPM was the low precision in the estimation of the daily egg production and the spawning fraction. Alternative methodologies to increase the precision of P0 and S are discussed. In spite of the high variance of the spawning biomass estimates, the use of DEPM offers valuable information to adjust acoustic estimates and provides time series of anchovy population size and biological parameters for basic research.

scholarly journals First thorough assessment of de novo oocyte recruitment in a teleost serial spawner, the Northeast Atlantic mackerel (Scomber scombrus) case

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Thassya C. dos Santos Schmidt ◽  
Anders Thorsen ◽  
Aril Slotte ◽  
Leif Nøttestad ◽  
Olav S. Kjesbu
Keyword(s):  
Egg Production ◽  
De Novo ◽  
Seasonal Pattern ◽  
Production Method ◽  
Spawning Period ◽  
Northeast Atlantic ◽  
Atlantic Mackerel ◽  
Scomber Scombrus ◽  
Stock Biomass ◽  
Spawning Stock

AbstractThe understanding of teleost fecundity type (determinate or indeterminate) is essential when deciding which egg production method should be applied to ultimately estimate spawning stock biomass. The fecundity type is, however, unknown or controversial for several commercial stocks, including the Northeast Atlantic mackerel (Scomber scombrus). Aiming at solving this problem, we applied state-of-the-art laboratory methods to document the mackerel fecundity type, including any de novo oocyte recruitment during spawning. Initially, active mackerel spawning females were precisely classified according to their spawning status. The number and size of all phasei-specific oocytes (12 phases), with a special attention to previtellogenic oocytes phases (PVO [PVO2 to PVO4a–c]), were also thoroughly investigated. Examinations of relative fecundity (RFi) clarified that the latest phase of PVOs (PVO4c) are de novo recruited to the cortical alveoli–vitellogenic pool during the spawning period, resulting in a dome-shaped seasonal pattern in RFi. Hence, we unequivocally classify mackerel as a true indeterminate spawner. As PVO4c oocytes were currently identified around 230 µm, mackerel fecundity counts should rather use this diameter as the lower threshold instead of historically 185 µm. Any use of a too low threshold value in this context will inevitably lead to an overestimation of RFi and thereby underestimated spawning stock biomass.

Spatiotemporal modelling for the annual egg production method of stock assessment using generalized additive models

1998 ◽  
Vol 55 (12) ◽  
pp. 2608-2621 ◽  
Author(s):  
N H Augustin ◽  
D L Borchers ◽  
E D Clarke ◽  
S T Buckland ◽  
M Walsh
Keyword(s):  
Environmental Variables ◽  
Egg Production ◽  
Survey Design ◽  
Stock Assessment ◽  
Generalized Additive Models ◽  
Production Method ◽  
Additive Models ◽  
Atlantic Mackerel ◽  
Egg Density ◽  
Survey Designs

Generalized additive models (GAMs) are used to model the spatiotemporal distribution of egg density as a function of locational and environmental variables. The main aim of using GAMs is to improve precision of egg abundance estimates needed for the annual egg production method. The application of GAMs requires a survey design with good coverage in space and time. If the only results available are from less optimal survey designs, they can be improved by using historical data for spawning boundaries. The method is applied to plankton egg survey data of Atlantic mackerel (Scomber scombrus) in 1995. The GAM-based method improves the precision of estimates substantially and is also useful in explaining complex space-time trends using environmental variables.

scholarly journals DEVELOPMENT STAGE, AGEING AND NATURAL MORTALITY OF ANCHOVY EGGS (Encrasicholina SPECIES) FROM BACAN

2017 ◽  
Vol 4 (2) ◽  
pp. 52
Author(s):  
Retno Andamari ◽  
Andriko N. Susanto ◽  
David A. Milton
Keyword(s):  
Egg Production ◽  
Production Method ◽  
Development Stage ◽  
Large Series ◽  
Natural Mortality

ln order to study the possible application of the Daily Egg Production Method (DEPM) for estimating anchovy (Encrasicholina spp.) biomass at Bacan. Maluku, we collected a large series of plankton samples.

First report on the diet and reproductive biology of red-toothed triggerfish Odonus niger (Ruppell, 1836) from the south-eastern Arabian Sea

2021 ◽  
pp. 1-11
Author(s):  
Nitin Kanji Suyani ◽  
Mridula Rajesh ◽  
Kothanahally Mallegowda Rajesh
Keyword(s):  
Reproductive Biology ◽  
Arabian Sea ◽  
Feeding Habits ◽  
Gonadosomatic Index ◽  
Biological Information ◽  
The South ◽  
Spawning Period ◽  
South Eastern ◽  
Eastern Arabian Sea ◽  
Males And Females

Abstract The feeding habits and reproductive biology of red-toothed triggerfish Odonus niger (Ruppell, 1836) was analysed from 449 specimens collected from the Karnataka coast of the south-eastern Arabian Sea. Of the total stomachs examined, only 54 (12%) were empty and 395 contained food remains. The diet comprised crustacean remains (48.0%), zooplankton (21.4%), algae (16.5%), fish remains (6.1%) and cephalopod remains (5.3%) along with partially digested matter (2.3%) and detritus (0.4%). The species was found to be a generalist feeder and an omnivore. The overall sex ratio between males and females (1: 0.44) was significantly (P < 0.05) different. Histological examination of the ovaries indicated asynchronous ovarian development in females, with males maturing earlier than females. The gonadosomatic index (GSI) patterns of males and females, and the presence of ripe ovaries and spermatozoids suggested that April–May is the peak spawning period. The absolute and relative fecundity estimates ranged from 16,464–312,420 eggs and 251–2812 eggs g−1 respectively. Fecundity was positively correlated with total length and body weight. The biological information on diet composition and reproductive traits provided for the first time in this study can facilitate conservation, management and sustainable exploitation of this species in the study area.

Size and Density Dependent Mating Tactics in the Simultaneously Hermaphroditic Seabass Serranus Subligarius (Cope, 1870)

Behaviour ◽  
1997 ◽  
Vol 134 (7-8) ◽  
pp. 563-594 ◽  
Author(s):  
Ann S. Oliver
Keyword(s):  
Mating Behavior ◽  
Evolutionarily Stable Strategy ◽  
Small Fish ◽  
Large Fish ◽  
Mating Tactics ◽  
Spawning Period ◽  
Female Pair ◽  
Fish Trade ◽  
Evolutionarily Stable ◽  
Daily Spawning

AbstractThis study examines factors within the mating system of Serranus subligarius (belted sandfish) that are likely to maintain simultaneous hermaphroditism as an evolutionarily stable strategy in a highly mobile, high density species. I focus on changes in mating behavior with size. Mating behavior was observed underwater in the northeastern Gulf of Mexico at St. Andrew Bay State Park. Every hermaphrodite can spawn in three roles over the course of the daily spawning period: female pair spawn, male pair spawn, and male streak spawn. Pair spawning fish trade eggs, taking turns fertilizing one another's eggs. Egg trading is not symmetrical; the smaller fish in a pair spawns more often in the female role than the larger fish. Overall, small fish ( 70 mm SL) pair spawn more frequently as females, while large fish ( 80 mm SL) pair spawn more often as males. A size advantage appears to exist for male function. However, large fish usually release at least one egg parcel per spawning

Improving the precision of the daily egg production method using generalized additive models

1997 ◽  
Vol 54 (12) ◽  
pp. 2727-2742 ◽  
Author(s):  
D L Borchers ◽  
S T Buckland ◽  
I G Priede ◽  
S Ahmadi
Keyword(s):  
Egg Production ◽  
Survey Methods ◽  
Functional Dependence ◽  
Generalized Additive Models ◽  
Substantial Reduction ◽  
Large Degree ◽  
Production Method ◽  
Additive Models ◽  
Sample Survey ◽  
Stochastic Variation

Generalized additive models (GAMs) are used to model spatial variation in egg density and increase the precision of biomass estimates from the daily egg production method. Application of GAMs to survey data from the western mackerel (Scomber scombrus) and horse mackerel (Trachurus trachurus) stocks result in a substantial reduction in coefficients of variation of egg abundance. In developing GAM methods for the daily egg production method, we generalize Pennington's method, in which presence-absence is modelled separately from nonzero observations, and use a new form of the bootstrap that accommodates clustered count data without requiring explicit modelling of the form of clustering. In addition to increasing estimation precision, the use of GAMs has several advantages over stratified sample survey methods. To a large degree they allow the data to determine the form of functional dependence of the response on explanatory variables; they accommodate a wide variety of forms of stochastic variation of the response; they provide maps of the predicted density within the survey area; they provide an objective means of interpolating into unsampled areas; and estimation does not assume random sampling with respect to location.

scholarly journals Assessing natural mortality of Bay of Biscay anchovy from survey population and biomass estimates

2016 ◽  
Vol 73 (2) ◽  
pp. 216-234 ◽  
Author(s):  
Andrés Uriarte ◽  
Leire Ibaibarriaga ◽  
Lionel Pawlowski ◽  
Jacques Massé ◽  
Pierre Petitgas ◽  
...  
Keyword(s):  
Egg Production ◽  
Linear Models ◽  
Production Method ◽  
Natural Mortality ◽  
Bay Of Biscay ◽  
Stock Assessments ◽  
Long Time ◽  
Using Data ◽  
Log Linear ◽  
Firm Evidence

The closure of the anchovy (Engraulis encrasicolus) fishery in the Bay of Biscay between 2005 and 2010 because of low biomass levels provided an opportunity to estimate natural mortality using data from egg (daily egg production method, DEPM) and acoustic surveys implemented for the assessment of this population since 1987. Assuming that natural mortality (M) is constant over time and that catchability in both surveys is equal for all ages, M could be estimated using log-linear models on the series of surveys of population numbers at age and seasonal integrated stock assessments. The analysis suggests M values of around 0.9 for a common natural mortality at all ages. However, we found firm evidence that natural mortality at ages 2 and older (M2+) is markedly higher than at age 1 (M1), which indicates senescent mortality, a possibility suggested a long time ago for this type of short-lived species.

A reanalysis of North Sea plaice spawning-stock biomass using the annual egg production method

2009 ◽  
Vol 66 (9) ◽  
pp. 1999-2011 ◽  
Author(s):  
Cindy J. G. van Damme ◽  
Loes J. Bolle ◽  
Clive J. Fox ◽  
Petter Fossum ◽  
Gerd Kraus ◽  
...  
Keyword(s):  
North Sea ◽  
Egg Production ◽  
Stock Assessment ◽  
Population Analysis ◽  
Spatial Dynamics ◽  
Production Method ◽  
Southern Bight ◽  
The North ◽  
Stock Biomass ◽  
Spawning Stock

Abstract van Damme, C. J. G., Bolle, L. J., Fox, C. J., Fossum, P., Kraus, G., Munk, P., Rohlf, N., Witthames, P. R., and Dickey-Collas, M. 2009. A reanalysis of North Sea plaice spawning-stock biomass using the annual egg production method. – ICES Journal of Marine Science, 66: 1999–2011. Uncertainty about the quality of current virtual population analysis-based stock assessment for North Sea plaice (Pleuronectes platessa) has led to various abundance indices. We compared biomass estimates from the annual egg production (AEP) method with current stock assessments based on catch-at-age to validate the current and historical perception of exploitation. The AEP method was also used to investigate the dynamics of the spatial components of plaice in the North Sea. We corrected for fecundity down-regulation and changes in sex ratio. Estimates from both methods were similar in trend and absolute biomass. On the Dogger Bank, there was a dramatic decline in biomass from 1948 and 1950 to 2004, and in the Southern Bight, the stock appeared to increase from 1987 and 1988 to 2004, although not reaching the historically high levels of 1948 or 1950. The timing of spawning of North Sea plaice does not appear to have changed throughout the period of high exploitation. We conclude that the AEP method is a useful way to hindcast the spatial dynamics of heavily exploited flatfish stocks.

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