An acoustic survey in the southeastern Black Sea in the assessment of trachurus mediterraneus (Steindachner, 1868) distribution

Abstract

Horse mackerel (Trachurus mediterraneus, Steindachner, 1868) is an important commercial fish distributed along the coast of Turkey. Although, the variety of catching amount of the species fluctuate by years, it is obvious that the stocks are getting smaller. In this study the mid-trawl sampling alongside the acoustic data revealed the lack of adult individuals. And the juvenile fish constituted an alarmingly large part of the overwintering stocks. Thus, The General Fisheries Commission (GFCM) has assessed the status of Horse mackerel stock for the Mediterranean since 2013. Due to the defects in the current assessment methods, the commission has recommended to modify and improve the data collection techniques that provide biomass data and abundance indices such as hydro-acoustics. The key advantage of hydro-acoustics is its capability to predict most measurement errors, eliminate the defects and provide a level of total abundance reliability that other methods can only approximate. Fisheries independent data, which authorities has identified as a critical deficiency that weaken the reliability of the stock status assessments was provided with this study.