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


Pavez, C and Wotherspoon, S and Maschette, D and Reid, K and Swadling, K, Recruitment modelling for Euphausia superba stock assessments considering the recurrence of years with low recruitment, Commission for the Conservation of Antarctic Marine Living Resources, 11 June (2021) [Refereed Conference Paper]

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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.

Item Details

Item Type:Refereed Conference Paper
Keywords:krill assessment, Antarctica, recruitment
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 crustaceans (excl. rock lobster and prawns)
UTAS Author:Pavez, C (Dr Cassandra Pavez)
UTAS Author:Wotherspoon, S (Dr Simon Wotherspoon)
UTAS Author:Maschette, D (Mr Dale Maschette)
UTAS Author:Swadling, K (Associate Professor Kerrie Swadling)
ID Code:155012
Year Published:2021
Deposited By:Sustainable Marine Research Collaboration
Deposited On:2023-01-23
Last Modified:2023-01-25

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