About the whale map
Vessel strikes are one of the leading anthropogenic causes of large whale mortality. The Norwegian Sea, Barents Sea and surrounding waters host fin, blue, sperm, humpback and minke whales alongside some of Europe's busiest shipping lanes. This tool overlays cetacean observation density with gridded vessel density. Port and region scores use weighted observations and a speed factor; the shipping overlay is visual context and is not used numerically in those scores.
The Mesh Oslo "What else can you build" prompt highlighted whale incident tracking as an open problem. Hubocean.earth and the One Ocean Expedition show how rich open ocean data has become; this app uses a small, public slice of that for a single, pragmatic question: where do whales and ships overlap, and how does cutting vessel speed change strike lethality.
A sister project, Coexisting with Birds, answers the same question for wind farms and birdlife.
Conservation status
The map shows two parallel categorisations. The Norwegian Red List 2021 (Artsdatabanken) covers national populations; the global IUCN Red List covers the species worldwide. We display the stricter of the two, and call out the divergence where it matters (e.g. the fin whale is VU globally and LC nationally because the Norwegian feeding population is recovering).
| CR | Critically endangered Extremely high risk of extinction. |
| EN | Endangered Very high risk of extinction. |
| VU | Vulnerable High risk of extinction. |
| NT | Near threatened Close to qualifying for a threatened category. |
Strike vulnerability per species
Risk scales with body size, surface time and overlap with shipping routes. We use the species accounts
in
Laist D.W. 2001
Laist D.W., Knowlton A.R., Mead J.G., Collet A.S., Podesta M. (2001). Collisions between ships and whales. Marine Mammal Science, 17(1), 35-75.
Foundational ship-strike record table. Most lethal injuries occur at vessel speeds ≥ 14 knots.
doi: 10.1111/j.1748-7692.2001.tb00980.x
Open source
,
Rockwood R.C. 2017
Rockwood R.C., Calambokidis J., Jahncke J. (2017). High mortality of blue, humpback and fin whales from modeling of vessel collisions on the U.S. West Coast suggests population impacts and insufficient protection. PLOS ONE, 12(8), e0183052.
Encounter-theory mortality model. Per-cell expected strikes integrate whale density, ship density, vessel speed and lethality.
doi: 10.1371/journal.pone.0183052
Open source
and
Nisi A.C. et al. 2024
Nisi A.C. et al. (2024). Ship collision risk threatens whales across the world’s oceans. Science, 385, 1136-1141.
Global blue, fin, humpback and sperm whale habitat-vs-traffic overlap. Mandatory speed restrictions cover only 0.54 percent of blue whale collision-risk hotspots.
doi: 10.1126/science.adp1950
Open source
to
classify each cetacean as high, medium or low vulnerability.
| ▲ | High vulnerability Large slow surface dwellers. Includes blue, fin, sei, humpback, sperm whale and the North Atlantic right whale (functionally absent from NE Atlantic but listed for completeness). |
| ● | Moderate vulnerability Common minke whale, killer whale, long-finned and short-finned pilot whales. |
| no icon | Lower vulnerability Agile small cetaceans (porpoises, dolphins) and deep divers (beaked whales). Bycatch and acoustic disturbance dominate over direct strikes for these species. |
Heatmap and points
The heatmap uses a 10K stratified sample from GBIF (taxonKey 733) covering the bounding box lat 56-82, lon -10 to 70 across all twelve months. Counts reflect where people record whales, not absolute abundance. Coastal and tourist viewpoints (Andoya, Lofoten, Tromso) are overrepresented. Points view shows individual records colored by species; click a point for details.
| Low to high cetacean observation density | |
| Major Norwegian port (icon size scales with annual cargo throughput) |
Per port strike risk
Each major port is colored from green (low) through yellow to red (very high) based on a composite weighted score of nearby observations.
| Red list weight | |
| CR | × 8 |
| EN | × 5 |
| VU | × 3 |
| NT | × 1.5 |
| Least concern (LC) / Data deficient (DD) | × 1 |
| Strike vulnerability | |
| High | × 3 |
| Medium | × 1.5 |
| Low | × 1 |
Logistic curve for P(lethal) vs vessel speed in knots. β0 = -4.89, β1 = 0.41. P=0.5 at v=11.8 kn.
doi: 10.1111/j.1748-7692.2006.00098.x
Open source ). The default speed is 14 knots.
Vessel speed and lethality
The probability that a struck large whale dies or is severely injured rises sharply with vessel
speed. The app uses the Vanderlaan and Taggart 2007 logistic
Vanderlaan A.S.M. 2007
Vanderlaan A.S.M., Taggart C.T. (2007). Vessel collisions with whales: the probability of lethal injury based on vessel speed. Marine Mammal Science, 23(1), 144-156.
Logistic curve for P(lethal) vs vessel speed in knots. β0 = -4.89, β1 = 0.41. P=0.5 at v=11.8 kn.
doi: 10.1111/j.1748-7692.2006.00098.x
Open source
:
The 10 knot line is an illustrative comparison. With the coefficients used here, the conditional estimate is about 31% at 10 knots. This curve describes injury given a collision for large whales, not the probability of encountering or striking a whale.
Encounter rate (advanced)
For per cell mortality, Rockwood et al. 2017 (
Rockwood R.C. 2017
Rockwood R.C., Calambokidis J., Jahncke J. (2017). High mortality of blue, humpback and fin whales from modeling of vessel collisions on the U.S. West Coast suggests population impacts and insufficient protection. PLOS ONE, 12(8), e0183052.
Encounter-theory mortality model. Per-cell expected strikes integrate whale density, ship density, vessel speed and lethality.
doi: 10.1371/journal.pone.0183052
Open source
) factor the rate of
encounters out of the strike physics:
I(v_b, v_w) is the Gerritsen-Strickler velocity correction term; for v_b ≫ v_w it approaches 1. P_strike_depth is the fraction of time the whale is in the hull-swept depth band (typically 0.4 to 0.6 from tag data). P_avoidance is the chance of last second evasion (0 by default, conservative).
Williams and O'Hara 2010 (
Williams R. 2010
Williams R., O’Hara P. (2010). Modelling ship strike risk to fin whales, humpback whales and killer whales in British Columbia, Canada. Journal of Cetacean Research and Management, 11(1), 1-8.
Spatial co-occurrence risk: R(i,j) = whale_density × ship_density. Map of relative risk hotspots.
Open source
) take the simpler co-occurrence
approach: relative risk per cell is whale_density × ship_density. Redfern et al. 2013
(
Redfern J.V. et al. 2013
Redfern J.V. et al. (2013). Assessing the risk of ships striking large whales in marine spatial planning. Conservation Biology, 27(2), 292-302.
Marine spatial planning use case. Integrates whale density along vessel routes.
doi: 10.1111/cobi.12029
Open source
) integrate this along candidate shipping routes, the canonical
marine spatial planning citation.
Region density layer
When toggled on, each sea region is colored by observation count. Empty regions appear in grey, indicating low data confidence rather than absence of whales. With a 10K sample over four large IHO sea areas, expect at most a few thousand records per region.
Data sources
Logistic curve for P(lethal) vs vessel speed in knots. β0 = -4.89, β1 = 0.41. P=0.5 at v=11.8 kn.
Bayesian re-fit of the lethality-vs-speed curve. P(mortality) ≈ 0.21 at 10 kn, 0.50 at 15 kn.
Foundational ship-strike record table. Most lethal injuries occur at vessel speeds ≥ 14 knots.
Encounter-theory mortality model. Per-cell expected strikes integrate whale density, ship density, vessel speed and lethality.
Spatial co-occurrence risk: R(i,j) = whale_density × ship_density. Map of relative risk hotspots.
Marine spatial planning use case. Integrates whale density along vessel routes.
Global blue, fin, humpback and sperm whale habitat-vs-traffic overlap. Mandatory speed restrictions cover only 0.54 percent of blue whale collision-risk hotspots.
10-knot mandatory speed limit in Seasonal Management Areas; 80-90 percent reduction in mortality risk.
Voluntary guidance: traffic separation schemes, areas to be avoided, seasonal speed reduction, crew training.
Global ship strike database including reports from Norwegian waters.
CC BY 4.0 / CC0 / CC BY-NC 4.0 (per contributing dataset). 137,820 records in our bounding box; 10K stratified sample shown here.
National red list. 27 of 71 mammal species are red-listed; cetacean entries concentrated on Arctic and great whales.
Global IUCN Red List assessments for cetaceans, updated periodically.
Four cetaceans listed: bowhead, North Atlantic right whale, blue whale, harbour porpoise.
Conservation agreement covering all small cetaceans except sperm whale.
Member states: Norway, Iceland, Greenland, Faroes. Provides species accounts and management advice.
1×1 km grid shipping density (hours/km^2/month), 2017-2024. AIS data via CLS, ORBCOMM and vesseltracker.com.
Norwegian EEZ outlines (mainland MRGID 5686, Jan Mayen 8437, Svalbard 33181). CC BY 4.0.
Public domain coastline data, clipped to Norwegian waters bbox.
Discusses anthropogenic stressors including shipping in Norwegian waters.
Annual abundance estimates from line-transect surveys.
Limitations
This is a screening tool, not an environmental impact assessment. Cetacean records reflect
observer effort, not true density. EMODnet's vessel density grid is a 2017 to 2024 average.
Norwegian-waters specific strike-risk modelling is sparse in the literature; we apply global
physics and global species accounts. For real planning, use site specific surveys, Kystverket /
BarentsWatch live AIS and modelled species distributions from
Havforskningsinstituttet (
Havforskningsinstituttet (Institute of Marine Research) 2026
Havforskningsinstituttet (Institute of Marine Research) (2026). Cetacean abundance estimates from NILS surveys. IMR.
Annual abundance estimates from line-transect surveys.
Open source
).
Project
Built by Almaz Ermilov in Oslo, April 2026. MIT licensed, free to fork.
GitHub repository · Coexisting with Birds (sister project) · HUB Ocean (inspiration)
All data from open sources. Code is open source under MIT.
Saved sample and place names
The bundled GBIF sample was committed in April 2026. The original retrieval timestamp is unavailable. Its 9,996 observations span multiple years and use monthly quotas; month coverage is not seasonal abundance. Saving a browser snapshot does not refresh these observations.
Place names come from GeoNames, under CC BY 4.0. The local extract covers populated places in Norway. External OpenStreetMap and EMODnet tiles are not stored by the application snapshot.