Abstract
Protein from fish is essential for feeding the world’s population and is increasingly recognized as critical for food security. To ensure that fisheries resources can be sustainably maintained, fisheries management must be appropriately implemented. When logbook and landing records data are not complete or are incorrect, it is challenging to have an accurate understanding of catch volume. Focusing on Indonesian longline vessels operating in the Indian Ocean from 2012–2019 (n = 1124 vessels), our aims were to (1) assess compliance through identification of landing sites and potentially illicit behavior inferred by interruptions in VMS transmission, and (2) understand how the fishery operates along with quantifying the spatio-temporal distribution of fishing intensity by applying a Hidden Markov Model, which automatically classified each VMS position as fishing, steaming and anchoring. We found vessel compliance gaps in 90% of vessels in the dataset. Compliance was questionable due both to the widespread occurrence of long intermissions in relaying VMS positions (mean = 17.8 h, n = 973 vessels) and the use of unauthorized landing sites. We also observed substantial changes in fishing effort locations among years. The introduction of regulatory measures during the study period banning transshipment and foreign vessels may be responsible for the spatial shift in fishing activity we observed, from encompassing nearly the whole Indian Ocean to more recent intense efforts off western Sumatra and northern Australia.
Highlights
Protein from fish is essential for feeding the world global population and is increasingly recognized as critical for food security
The system we developed is based on an automated workflow, which starts with raw vessel monitoring system (VMS) data and ends with data segregated by vessel and trip, and labeled with a type of activity for each VMS position
We flagged VMS positions associated with a temporal gap in transmission interval if the time difference between consecutive VMS positions was greater than 4 h and the vessel was at sea
Summary
Protein from fish is essential for feeding the world global population and is increasingly recognized as critical for food security. It has been projected that by 2030, about 35–40 million tonnes of fish will be required annually to satisfy global demand (Delgado et al, 2003). Wild fish stocks are increasingly depleted, as demonstrated by the consistent reduction in the proportion of stocks that are biologically sustainable, from 90% in 1974 to 65.8% in 2017 (FAO, 2020). This downward trend is largely the result of insufficient or ineffective fisheries. It has been noted that environmental degradation and climate change are major forces affecting the world fish populations (Rijnsdorp et al, 2009)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
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 callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
