Diurnal variation models of bottom trawl survey catches parameterised by using commercial CPUE data
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http://hdl.handle.net/11250/106605Utgivelsesdato
2004Metadata
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Introduction: Diurnal variation is observed in almost all marine surveys and can cause biased abundance and length frequency estimates. Symmetric logistic
models developed by Hjellvik et al. (2001) were utilized to investigate diurnal variation in catch rates of hake (Merluccius spp.) of trawlers for
the period 1997-2002 and of hake surveys (1990-2003) in Namibian waters. The large numbers of commercial tows have a very good
geographical, seasonal and temporal resolution that enabled us to study the influence of various explanatory variables on diurnal fluctuation
model parameters. These results were thereby used to facilitate the modelling of diurnal variation in Namibian hake trawl survey catches.