engleski

Preliminary experiences in aplying the stereoscopic system in Bluefin tuna size estimates

A stereoscopic camera AQ100 was used in 16 transferring events during which fish were stocked into 9 cages located at three bluefin tuna farms in the Croatia. Aiming to test the accuracy of the fish length obtained by stereoscopic camera, 112 fish were randomly sampled from the cages, measured for fork length (FL in cm) and total weight (WT in kg), then placed into the sea for subsequent measurement. The tuna filmed with stereoscopic camera and on board measured with caliper ranged from 73.5 to 97.0 cm in FL with an average of 78.75 ± 3.6 cm, and 8.0 to 17.6 kg in total weight with an average of 9.57 ± 1.5 kg. Length-weight relationships were compared among measured and estimated ones. Different levels of errors were considered to get insight into the accuracy of estimates of FL and WT. Obtained differences between estimates and direct measurements as well as calculated errors in length-weight relationships are encouraging in making a reliable, non invasive measurement of length frequency distribution of the wild bluefin tuna catch.

Tuna fisheries ; Adriatic Sea ; imaging techniques ; size composition

nije evidentirano