Fishing Overlays
The oceanographic overlays that reveal productive waters: sea-surface altimetry, chlorophyll, per-species fishing intelligence, and marine heatwaves.
Where to find it
Map › floating Overlays button (top-left corner of the map) › Fishing tab (fish icon).
The Overlays button shows a badge with the number of active overlays. Once opened, the panel presents a row of category tabs; select the Fishing tab to reach the four overlays described here.
Hierarchy
Overlays (floating panel)
└── Fishing (tab)
├── SSH Altimetry
├── Chlorophyll
├── Fishing Intelligence
└── Marine Heatwaves
SSH Altimetry
SSH Altimetry
What it's for: Displays the sea-surface height anomaly (Copernicus NRT). The bumps and dips of the surface betray eddies, upwellings, and geostrophic currents. Fronts between warm (positive) and cold (negative) water concentrate plankton, and therefore baitfish and predators.
How to use it: 1. Open the Overlays panel from the map. 2. Select the Fishing tab. 3. Click SSH Altimetry to turn it on (the button highlights). 4. Read the colour map: look for tight gradients (fronts) and circular structures (eddies), the most promising zones.
Options & settings:
| Control | Effect |
|---|---|
| SSH Altimetry button | Turns the sea-surface height anomaly overlay on / off. |
Tips & limits: - Near-real-time satellite altimetry data (Copernicus NRT): global coverage but a relatively coarse grid, better suited to reading large offshore structures than the coast. - Cross-reference with chlorophyll: an SSH eddy rimmed by a chlorophyll front is a strong signal.
Chlorophyll
Chlorophyll
What it's for: Displays chlorophyll-a concentration (Copernicus NRT, 4 km resolution). It is the direct indicator of phytoplankton, hence of productive waters and the zones where the food chain — and the fish — gathers.
How to use it: 1. In the Fishing tab, click Chlorophyll. 2. Identify the tongues of rich water (high concentration) meeting the clear blue (poor) water: those edges are the feeding fronts.
Options & settings:
| Control | Effect |
|---|---|
| Chlorophyll button | Turns the chlorophyll-a concentration overlay on / off. |
Tips & limits: - No data over land, the coastline, or under cloud cover: a message flags it (chlorophyll is measured by optical satellite, and cloud masks the signal). - Combine with SSH Altimetry to tell a plain coastal bloom apart from a front genuinely structured by an eddy.
Fishing Intelligence
Fishing Intelligence
What it's for: An interactive overlay that combines sea-surface temperature (SST), chlorophyll, depth, season, and moon phase to estimate a per-species probability of presence, point by point.
How to use it: 1. In the Fishing tab, click Fishing Intelligence to turn it on. 2. A reminder appears: Click anywhere at sea to query. 3. Click anywhere on the water to get the per-species assessment for that point.
Options & settings:
| Control | Effect |
|---|---|
| Fishing Intelligence button | Turns the click-to-query mode on / off. |
| Click anywhere at sea to query hint | Reminder shown while the overlay is active. |
Tips & limits: - The result appears only after a click at sea; clicking on land returns nothing. - The estimate depends on SST and chlorophyll data being available under the point (cloudy or coastal areas are less reliable). - For the species detail and the SST / chlorophyll / moon logic, see the Atlas tab in the sidebar.
Marine Heatwaves
Marine Heatwaves
What it's for: Maps active marine heatwaves, classified by Hobday categories (I to IV), from ESA CCI SST data. These temperature anomalies upend species distribution and can empty or displace zones that are normally productive.
How to use it: 1. In the Fishing tab, click Marine Heatwaves. 2. Clusters appear as coloured patches, together with event centroids marking their core. 3. The colour indicates intensity (Hobday category I to IV).
Options & settings:
| Control | Effect |
|---|---|
| Marine Heatwaves button | Turns the active marine heatwave overlay on / off. |
Tips & limits: - The overlay shows active events: an area without a patch is simply not in a heat anomaly at the time consulted. - Centroids pinpoint the centre of each event; the patches show its extent.