Open AccessAcoustic correction factor estimate for compensating vertical diel migration of small pelagics
Author(s) -
A. Bonanno,
Marco Barra,
Andrea De Felice,
Marianna Giannoulaki,
M. Iglesias,
Iole Leonori,
Ana Ventero,
Salvatore Aronica,
Ilaria Biagiotti,
Vjekoslav Tičina,
Giovanni Canduci,
Simona Genovese
Publication year - 2021
Publication title -
mediterranean marine science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.734
H-Index - 38
eISSN - 1791-6763
pISSN - 1108-393X
DOI - 10.12681/mms.25120
Subject(s) - pelagic zone , diel vertical migration , mediterranean sea , environmental science , daytime , biomass (ecology) , oceanography , zooplankton , mediterranean climate , sampling (signal processing) , abundance (ecology) , physical geography , geography , fishery , climatology , geology , ecology , atmospheric sciences , biology , computer science , filter (signal processing) , computer vision
Differences in acoustic estimates of small pelagic fish biomass, due to data acquisition during daytime and nighttime surveys, have been recognized for many years as a problem in acoustic surveys. In the absence of a single rule for all species and for all locations, some expert groups identified specific time intervals for acoustic data acquisition in relation to the schooling behavior of the target species. In the Mediterranean Sea, the research groups working in the MEDIAS (Mediterranean International Acoustic Survey) agreed on the importance that acoustic sampling are conducted only during day-time. Only when available time does not permit to complete the survey during daytime, data collection might be extended. In this case, working on data collected during both daytime and nighttime, a bias may occur in the biomass estimates. In order to evaluate and correct such bias, specific experiments were performed in some geographical sub-areas of the Mediterranean Sea. The data analysis allowed the estimation of a mean correction factor for the Strait of Sicily, where five surveys were carried out in different years. The correction factor was estimated also for the Adriatic Sea, Tyrrhenian Sea and Northern Spain; the observed variability among areas highlighted the importance of the spatial and temporal coverage of the survey area in order to obtain reliable estimates of the correction factor. Further studies are necessary to improve the interpretation of the obtained estimates in relation to area-related peculiarities such as zooplankton composition and abundance along with small pelagic fish community structure.