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Recruitment modelling for Euphausia superba stock assessments considering the recurrence of years with low recruitment

Version 2 2024-04-17, 04:02
Version 1 2023-05-23, 15:39
conference contribution
posted on 2024-04-17, 04:02 authored by Cassandra Pavez, S Wotherspoon, Dale MaschetteDale Maschette, K Reid, Kerrie SwadlingKerrie Swadling

Krill are a keystone species in the Southern Ocean food-web, and, as such, it is crucial to effectively manage the krill fishery to ensure its long-term sustainability. To assess the impacts of current harvesting pressures, evaluations rely on sampling and population modelling. Krill stock projections are developed with the Generalised Yield Model (GYM), which provides an assessment for stock status under current harvesting scenarios and various levels of uncertainties. One of the fundamental components of the GYM is the simulation of recruitment. De la Mare (1994) presents a proportional recruitment function for estimating krill recruitment based on estimates from field surveys. The De la Mare (1994) function uses estimates of the mean and variance of recruitment from survey data to determine the scaling of natural mortality and the distribution of random recruits that reproduce the observed mean and variance estimates. We evaluated De la Mare’s (1994) proportional recruitment function and found that for large variations in recruitment the function does not reproduce the observed mean proportion of recruits and its variance accurately. We review the deficiencies within the model and provide two alternative methods, which can support a wider range of values and possible extreme scenarios, such as years of low recruitment.


Department of Environment and Energy (Cwth)


Publication title

Commission for the Conservation of Antarctic Marine Living Resources






IMAS Directorate, Ecology and Biodiversity, Sustainable Marine Research Collaboration



Publication status

  • Published

Place of publication

Hobart, Tasmania

Event title

Commission for the Conservation of Antarctic Marine Living Resources

Rights statement

This paper is presented for consideration by CCAMLR and may contain unpublished data, analyses, and/or conclusions subject to change. Data in this paper shall not be cited or used for purposes other than the work of the CAMLR Commission, Scientific Committee or their subsidiary bodies without the permission of the originators and/or owners of the data

Socio-economic Objectives

100303 Wild caught crustaceans (excl. rock lobster and prawns)

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