Abstract
Most Atlantic salmon production takes place in large sea cages where there are limited opportunities to record growth on individual fish. This limits management capabilities for monitoring mean weight and thus total biomass, pellet sizes, feed volumes and the estimation of time until harvest. Furthermore, cause and effect of perturbations and arrested growth cannot be established or interceded on and genetic selection is limited to stocking and harvest measurements. The fusion of passive integrated transponder (PIT) identification and diode frames offers the possibility to noninvasively monitor the growth on thousands of individual fish. However, the accuracy of diode frame measurements for population- and individual level growth and biomass estimation has not been assessed. We stocked over 5000 individually PIT tagged Atlantic salmon post smolts in a net-cage in the sea and monitored growth using a diode frame and PIT tag reader. At the end of the growth period all fish were measured for body length and weight using the intensive gold standard methods of manual recording. At the population level diode frames were highly accurate with a mean difference of 0.002% for length and 4% for weight. Individual level length and weight records were repeatable 0.34 and 0.35, respectively. A single measurement at individual level from diode frames were moderately concordant with the gold standard measures (concordance correlation coefficient (CCC) of 0.52 for length and 0.57 for weight). By exploiting the repeatability and high throughput of diode frame measurements it was possible to increase the number of records per fish to a maximum of 5 resulting in CCC of up to 0.88 for length and 0.81 for weight. Diode frame measurements may hold promise for continuous growth measurements at sea needed in genetic evaluations.
Highlights
The Atlantic salmon (Salmo salar) aquaculture industry has undergone significant intensification and expansion since its inception in the 1970s, reaching a current global production of 2248 thousand tonnes in 2016 (FAO, 2018)
Cumulative mortalities of 6.5–9.0% have been reported by previous studies testing diode frames in Atlantic salmon sea cages (Føre et al, 2016)
The passive integrated transponder (PIT) tag reader regularly resulted in spurious duplicate readings per fish which were removed, these could be due to a fish remaining in close proximity to the antenna or multiple registrations as the fish passes through the energised antenna field, as is often reported with radio frequency identification (RFID) readers (Mahdin and Abawajy, 2011)
Summary
The Atlantic salmon (Salmo salar) aquaculture industry has undergone significant intensification and expansion since its inception in the 1970s, reaching a current global production of 2248 thousand tonnes in 2016 (FAO, 2018). Most Atlantic salmon production in countries like Norway, Scotland, Chile and Canada takes place in sea net-cages. The production trends have seen increasing net-cage sizes and capacities reaching (60,000–130,000 m3) and up to 200,000 fish per cage (Føre et al, 2018a, 2018b). Research into individualised fish response to management interventions, feed intake, growth and causes for arrested growth as well as genetic improvement have gained interest (Føre et al, 2018a, 2018b). Direct human observation of fish under these conditions is insufficient for decision support and on-line monitoring of physiological, behavioural and welfare of individual fish (Føre et al, 2018a, 2018b). A continuous on-line and non-invasive method of recording response variables of individual fish in situ could overcome the limitations of direct human observation and measurement
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
