Growing pressures by various human activities on the marine environment, and international commitments to the conservation of biodiversity or seafloor integrity have led to increased interest in marine spatial planning and in the tools required for an assessment of the impact of these pressures. Fishing is considered, given its widespread occurrence, to be the main human activity impacting the seafloor. Vessel Monitoring by Satellite (VMS) system data have been collected from 2000 onwards and cover the majority of EU fishing fleet capacity. These data have proven to be a valuable source of information on the spatial distribution of fishing effort: especially when combined with logbook data. The combined analyses, therefore, of VMS and logbook data allows researchers to investigate the fine details of fishing behaviour, and estimate the distribution of landings (and their cash values) at far higher precision than has been possible in the past. Furthermore the overall impact of fishing on the marine environment can be assessed.
The aim of this course is to introduce participants to best practice in the combined analysis of VMS and logbook data. Students will be guided through the entire process starting with the initial handling and processing of the raw data to the final estimation of appropriate indicators.
The objective of the course is to provide instruction in the use of the VMStools software package for the simultaneous analysis of VMS and logbook data. Emphasis will be placed on exploring the spatial distribution of fisheries, and the behaviour of fishers at sea. Students will be guided through the entire process of obtaining and cleaning VMS and logbook data, making simple plots and combining the datasets to enable more advanced analyses such as dispatching the landings at higher spatiotemporal resolutions (than is available in the logbook data) and calculating indicators (e.g. area of seabed fished). Instruction will also be given in how to use VMStools to convert logbook and VMS data to standard formats such as ICES FishFrame enabling pan-European datasets to be constructed in the future
This is a 5-day online course, in which the participants follow an online session 4 hours each day. Participants prepare for the online session by doing exercises intersessionally. The course is organized as online teaching on 8-12 February 2021, over Microsoft Teams.
1) ISLA: Individual Stress Level Analyses
The economic importance of specific fishing grounds to fishers varies within a fleet. To capture this variation and understand how dependent fishers are to an area we use the individual stress level analysis. We calculate the proportion of income coming from a specific area at the individual level and show the distribution of the individual stress level for the fleet considered. The stress level can be given for different groups (home harbours, vessel size, main gear), helping decision maker understand the sensitivity of closing particular areas and identify the part of the fishery impacted by their decision.
2) Aggregation of fishing
Swept Area Ratios for bottom gears are often calculated to quantify the impact on the benthic community. We demonstrate how to easily calculate SARs but also look at the location and intensity of fishing within ICES rectangles using a statistical approach. We use the underlying distribution of fishing intensity to more appropriately predict small scale (within an ICES rectangle) distribution of fishing under changes in effort.
3) Bycatch & high risk areas
The risk to repeatably catch small sized fish or vulnerable species has strong spatial correlation. We demonstrate how to display spatial species distribution-at-length from survey data and calculate spatial overlap with the fisheries from VMS and logbook data. We calculate a measure of spatial correlation of unwanted bycatch (either by species or by length) to come up with a measure that indicates the distance between consecutive fishing tows with low probability of similar catch composition.
4) Uncertainty in spatial fisheries data
VMS and logbook data are linked a posteriori to increase the spatial resolution of fishing activities. In this part we investigate how the assumptions made to 1) define when a vessel is fishing based on speed thresholds and 2) distribute the daily catch per ICES rectangle (resolution in logbooks) on fishing VMS points, influence the resulting maps. We also relate the temporal resolution of VMS data (interval between to pings) to the spatial resolution of maps as more frequent pings allow higher resolution maps.
Requirements for attending
The participants should have basic knowledge of R.
The participants should be familiar with practical 1 – 4 and 9 on https://github.com/nielshintzen/vmstools/wiki (practicals can be found under the “pages" dropdown menu on the right).
Register online by 25 January 2021.
Photo: Svanhildur Egilsdottir
Niels Hintzen, Wageningen Marine Research, The Netherlands
Katell Hamon, Wageningen Economic Research, The Netherlands
750 Euros for ICES member country affiliated participants
1250 Euros for non-member country affiliated participants