This article is Level 5 in the Filtering training series →
Comparing changes over time
You can use Starboard filters to compare changes in activity from large groups of AIS reporting vessels at different points in time. The Analysis results panel will give you a count of vessels and their type and flag based on the area, time, and filters you have set. You can then overlay this view with additional datasets in Starboard, such as environmental or satellite remote sensing layers, which will help you to assess potential reasons for any perceived activity changes over time.
Try it out: Compare the changes in distribution of CCSBT-licenced longline fishing vessels off the coast of Australia between the Jun-22 and Jun-23 fishing seasons.
Oceanographic Layers
Once you have isolated your fleets of interest using filters, you can then overlay and assess various oceanographic factors (found in Map Layers) for changes over time, such as ocean and wind conditions, sea ice concentration, sea surface temperature, and chlorophyll-a distribution.
Consider the following two panels, which show a filtered comparison of fishing distribution for CCSBT-licenced longline vessels west of Australia between the 2022-2023 fishing seasons.
Sea-surface temperature is the map layer used for oceanographic trend analysis in this example, but chlorophyll-a map layers could also be incorporated. Three initial points of interest are identified from the 2022-2023 seasons based on the side-by-side comparison of filtered data with oceanographic layers. Note that this type of analysis is best utilised over longer timeframes and with additional layers, in order to mitigate bias and natural fluctuations.
The CCSBT-licenced fishing vessels in this area have a preference for sea surface temperatures between 15-18 degrees celsius. This type of trend analysis can be used to identify outliers for investigation.
Vessels closer to Australia fished further south in 2022, likely due to warmer currents pushing down the Australian coast from the tropics, correlating to a significant negative phase of the Indian Ocean dipole climate driver. This can have an impact on patrol planning.
There was a 10% increase in fishing vessels registered to Indonesia and Japan from 2022 to 2023. This could indicate changes in global fleet operations, market trends, or catch allocations.
Learn more advanced fisheries analysis on our Youtube channel for Operation 18c →
Tip: You can make the process of comparative analysis easier by copying your Starboard URL, opening a new browser window, and pasting the URL to enable side-by-side comparison between timeframes and oceanographic layers. You can have unlimited instances of Starboard open in new tabs or windows, which enables quick and effective comparative analysis.
Analysing travel vectors to an area
You can also use filters to explore long travel histories for vessels that have been in your ports or areas of interest. Using the filtered results, you can zoom out and explore the prior movements of vessels on a global scale, assessing common travel vectors to your jurisdiction while identifying any anomalies in routes and intermediate port regions.
As an additional filter, try enabling the “Entered area from foreign port” funciton in the Area filter, to exclude local traffic from the Analysis results. This will help you to assess the least-to-most common flags visiting your ports or areas of interest, as well as their associated risk indicators and tags.
Filtering training series
Follow our Filtering training continuum to learn more advanced techniques:
Level 1: Using the filter toolbar →
Level 3: Combining filters, tags, and areas →