Reducing uncertainties in Baltic herring and sprat abundance estimates: Alternative approach to acoustic analyses

Kaljuste, OlaviSwedish University of Agricultural Sciences,Sveriges lantbruksuniversitet,Institutionen för akvatiska resurser,Department of Aquatic Resources (author)

Hydroacoustic studies using acoustic measurements combined with biological data obtained from trawl hauls remain a challenging task. The main purpose of the present study is to identify sources of uncertainty and compare the calculation methods for a mixed pelagic fish community of Baltic Sea. Most of the calculation methodologies use conventional statistical borders to split the study area, ignoring the possible natural population distribution areas. We compared the proposed “nearest haul” and the “subdivision average” with the conventional “rectangle average” on the Estonian regular acoustic surveys in the northeast Baltic Sea. The abundance estimates of the target species – European sprat Sprattus sprattus (Linnaeus 1758) and Baltic herring Clupea harengus membras (Linnaeus 1758) – with the “nearest haul” were significantly different from the currently used method, which indicates a strong effect of the allocation method. Our results indicate a need for a large scale comparative study to consider alternative calculation methodologies.

Sveriges lantbruksuniversitetInstitutionen för akvatiska resurser (creator_code:org_t)
Sveriges lantbruksuniversitet

In:Proceedings in Marine Technology and Ocean EngineeringLondon : CRC Press6, s. 721-7272638-647X

About the subject

AGRICULTURAL SCIENCES: AGRICULTURAL SCI ...; and Agriculture Fore ...; and Fish and Aquacul ...

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