Acoustical Estimations Confirm the Good Health of Gulf of Riga Herring

Acoustical Estimations Confirm the Good Health of Gulf of Riga Herring

Olavi Kaljuste, Tiit Raid, Faust Shvetsov, and Guntars Strods

Acoustical Estimations Confirm the Good Health of Gulf of Riga HerringThis is part of Fisheries Assessment and Management in Data-Limited Situations
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Description

The Baltic herring (Clupea harengus membras) is one of the most important commercial species of the Baltic Sea. The herring stocks have decreased remarkably in the Baltic proper in recent decades. At the same time, due to favorable environmental conditions and successful management the annual landings of local gulf population of Baltic herring have grown in recent years. The assessments are indicating the increasing trend of the abundance and biomass of gulf herring in the Gulf of Riga. In order to obtain catch-independent tuning data for the gulf herring stock assessments the joint Estonian-Latvian acoustic surveys were initiated in the whole Gulf of Riga in 1999. The results show that the Gulf of Riga as a semi-enclosed basin with favorable bottom topography and the settled character of gulf herring stock has off ered favorable conditions for successful implementation of the results of acoustical surveys into the assessment of gulf herring stock. Acoustically estimated number and biomass of gulf herring in the Gulf of Riga have been in good agreement with VPA estimates. This suggests high reliability of the abundance and biomass estimates and confirms the good health of gulf herring stock.

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