Andria and uncertainty in Bali sardinella

Andria started his analysis of acoustic survey estimates of Bali sardinella in 2012, with Knut Korsbrekke from the Institute of Marine Research (IMR) as his main supervisor. The project reached a happy end today when his thesis «Sources of uncertainty in acoustic survey estimates of Bali sardinella (Sardinella lemuru) in the Bali Strait, Indonesia» was examined and approved. The external examiner was Espen Johnsen from IMR.

Andria has studied acoustic survey data from the Bali Strait in Indonesia in 2010–2011. Five surveys were conducted during this period, but each survey had relatively limited coverage. Because the distribution of Bali sardinella is very heterogeneous (Bali sardinella is a schooling species), biomass estimates derived from these surveys are highly uncertain. Andria recommends that in the future, survey effort should be concentrated in fewer surveys that have better coverage, i.e., more transects with the same area, and that they should follow a stratification scheme where the effort is concentrated in the shelf areas where the fish tend to reside.