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Increasing the precision of the daily egg production method; 2020s remix of a 1980s classic


Ward, TM and Grammer, GL and Ivey, AR and Smart, JJ and McGarvey, R, Increasing the precision of the daily egg production method; 2020's remix of a 1980's classic, ICES Journal of Marine Science, 78, (4) pp. 1177-1195. ISSN 1054-3139 (2021) [Refereed Article]

Copyright Statement

Copyright 2021 International Council for the Exploration of the Sea

DOI: doi:10.1093/icesjms/fsab015


This paper reviews application of the Daily Egg Production Method (DEPM) to sardine (Sardinops sagax) off southern Australia between 1995 and 2019. Coefficients of variation (CVs) of estimates of spawning biomass (SB) were reduced from 2359% to 812% by: (i) estimating mean daily egg production (P0), spawning fraction (S), and sex ratio (R) from all historical data rather than annually; and (ii) combining batch fecundity (F) and female weight (W) into a single parameter, relative fecundity (F′ = Total daily egg production was estimated most precisely from annual estimates of spawning area (A) and estimates of P0 obtained from historical data. Both S and R were estimated most precisely from historical data. Estimating W and F from historical data did not increase precision. F′ had lower CVs than both W and F, and was stable across years and a wide range of W. Findings demonstrate that A can be converted into a precise estimates of SB using estimates of P0, S, R, and F′ obtained from historical data. However, the possibility that DEPM parameters may change in the future cannot be discounted. Future monitoring should include annual estimation of P0 and periodic (e.g. 35 years) re-estimation of adult parameters.

Item Details

Item Type:Refereed Article
Keywords:sardine, daily egg production method, spawning biomass
Research Division:Agricultural, Veterinary and Food Sciences
Research Group:Fisheries sciences
Research Field:Fisheries management
Objective Division:Animal Production and Animal Primary Products
Objective Group:Fisheries - wild caught
Objective Field:Wild caught fin fish (excl. tuna)
UTAS Author:Ward, TM (Associate Professor Timothy Ward)
ID Code:146708
Year Published:2021
Web of Science® Times Cited:2
Deposited By:Sustainable Marine Research Collaboration
Deposited On:2021-09-22
Last Modified:2021-11-16

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