Effectiveness of fully documented fisheries to estimate discards in a participatory research scheme

Abstract

a b s t r a c tA key challenge for fisheries science and management is the access to reliable and verifiable catch data. In science, the challenge is to collect reliable, precise and traceable data to provide sound advice. In management, the challenge is that catch documentation is necessary to enforce regulations. Currently, catch inspection at sea, self-reporting through e-log and on-board observers are the primary methods to document catches at sea. However, at-sea control and on-board observers are costly and have limited coverage, while self-reporting is susceptible to fraud and provides limited coverage. New cost-effective methods are currently emerging involving Remote Electronic Monitoring (REM) and on-board cameras. Previous studies have tested REM with promising results. However, evaluation of the potential biases of REM is needed before full benefits can be obtained. We deployed REM with on-board cameras on 14 fishing vessels and were able to inspect 56% of 1523 hauls made in the 6 month trial period, using an estimated 582 man-hours of video audit. The results showed an overall good agreement between the fishers self-reported discards and the video inspectors discard estimates. However, there was large variation in precision between individual vessels and species. Additionally, trial setup and process errors were shown to have a large effect on the precision of the video inspectors discard estimates. Nevertheless, despite challenges, REM was evaluated to have the potential to streamline monitoring and scientific documentation in a medium-size fishing fleet.

More data for the money: Improvements in design and cost efficiency of electronic monitoring in the Danish cod catch quota management trial

“…Onboard observers is currently the only MCS tool which can attain the same coverage level as EM and in fact for some metrics, such as age and mass estimates, allow for higher quality data than EM (Gilman et al, 2019;James et al, 2019). However, as other papers concerning EM with video have previously stated, the running costs of fisheries control with EM is lower than a similar coverage obtained with on-board observers and issues like observer safety at-sea and space limitations for an extra person on a vessel must also be taken into account (Gilman et al, 2019;James et al, 2019;Kindt-Larsen et al, 2011;Mangi et al, 2015;Mortensen et al, 2017;Needle et al, 2015).…”

“…The inclusion of hake is not possible to discern in the audit time but the change to a more precise length measurement increased the needed audit time. Another example is that Mortensen et al (2017) reported an average of 41 min per haul used for video audit, whereas the CCQM had an average audit time of 21 min per haul for vessels with conveyor belt and 38 min for vessels without conveyor belt in the last year of the trial. The two trials had similar vessel composition and the EM system applied was the same but the trial conducted by Mortensen et al (2017) also audited discards of plaice (Pleuronectes platessa) and Nephrops (Nephrops norvegicus) in addition to cod, saithe, hake, haddock and whiting.…”

“…Another example is that Mortensen et al (2017) reported an average of 41 min per haul used for video audit, whereas the CCQM had an average audit time of 21 min per haul for vessels with conveyor belt and 38 min for vessels without conveyor belt in the last year of the trial. The two trials had similar vessel composition and the EM system applied was the same but the trial conducted by Mortensen et al (2017) also audited discards of plaice (Pleuronectes platessa) and Nephrops (Nephrops norvegicus) in addition to cod, saithe, hake, haddock and whiting. Additionally, Mortensen et al (2017) covered vessels operating in the Baltic Sea and the audit procedures were different by not incorporating the gameboard setup used in the CCQM at the same time (2015).…”

“…The two trials had similar vessel composition and the EM system applied was the same but the trial conducted by Mortensen et al (2017) also audited discards of plaice (Pleuronectes platessa) and Nephrops (Nephrops norvegicus) in addition to cod, saithe, hake, haddock and whiting. Additionally, Mortensen et al (2017) covered vessels operating in the Baltic Sea and the audit procedures were different by not incorporating the gameboard setup used in the CCQM at the same time (2015). Besides the effect on needed audit time based on species coverage and analysis setup, the catch volume, catch composition and corresponding catch processing times have an effect on the needed audit time.…”

Evaluation and implementation of discards policies under catch-based fisheries management regimes

“…This includes understanding the mechanistic aspects of their gear's performance, but also an awareness of the behavioural responses of the species caught (Diaz Pauli and Sih, 2017;O'Neill et al, 2019). In recent years, most industry-science collaborations in Europe have taken such a bottom-up approach (Armstrong et al, 2013;Mortensen et al, 2017), and a number of gears such as the netting grids in the Scottish Nephrops fishery (Drewery et al, 2012;Kynoch et al, 2012) have been successfully introduced. Likewise, fishers' local ecological knowledge together with scientifically based mapping programs of areas with high presence of juveniles (Reid et al, 2019) is equally necessary for the development of spatial and temporal closure management systems and to design sustainable strategies on where, when and how to fish (Dunn et al, 2011;Rijnsdorp et al, 2012).…”