All You Need To Know About Ocean Roadkill


A dead, roadkill animal run over by a car on the highway is a sad and gruesome sight that most people have seen. But did you know there is ocean roadkill as well?

Ocean Roadkill

Ocean roadkill is a term sometimes used to describe the accidental deaths or injuries of marine animals due to collisions with vessels, similar to the way terrestrial animals can be affected by road traffic. Collisions with ships, also known as vessel strikes, can lead to serious injuries or fatalities for these animals. The most common victims of ocean roadkill include whales, dolphins, porpoises, sea turtles, and other marine mammals.

Why Do Vessel Strikes Occur?

According to NOAA Fisheries, collisions may occur anywhere vessels cross paths with marine life. Marine animals can be difficult for a vessel operator to see because they are not always clearly visible from the surface. And even if the operator sees the animal clearly, there may be no time for either of them to avoid a collision.

Furthermore, a large ship creates something called a ‘bow null effect’ blocking the engine noise by the bow, creating a quiet zone in front of the vessel, and leaving a whale unaware of the pending threat. Vessel strikes can occur anywhere in the world’s oceans where ships and marine animals co-occur.

Methods For Prevention 

The solutions that exist to prevent ship strikes vary depending on many factors, including whale distribution, behavior, habitat use, and ship routing options and limitations.

The World Shipping Council (WSC) has released a Whale Chart which offers seafarers critical navigational coordinates and concise graphics to identify routing measures and areas subject to static speed restrictions designed to protect whales and other cetaceans.

Studies have found that limiting boat speeds to 10 knots is estimated to reduce a North Atlantic right whale’s risk of death from being killed by a boat over 65 feet by between 80% and 90%.

Sadly, Oceana analyzed boat speeds from November 2020 through July 2022 in slow zones established by NOAA along the U.S. East Coast and found unfortunately that 84% of boats sped through mandatory slow zones, and 82% of boats sped through voluntary slow zones.

Regulatory Obligations 

Most vessels 65 feet or longer must travel at 10 knots or less in certain locations (called Seasonal Management Areas) along the U.S. East Coast at certain times of the year. This mandatory regulation reduces the likelihood of deaths and serious injuries to endangered North Atlantic right whales that result from collisions with vessels.

For instance, in the United States, ships of 300 gross tons and above must report to a shore-based station when entering two key right whale habitats: one in the northeast off the coast of Massachusetts and Cape Cod (year-round reporting required) and one in the southeast off the coast of Georgia and Florida (reporting required between 15 November and 16 April).

Additionally, temporary speed reduction zones, known as dynamic management areas and slow zones, can be established on short notice when right whales are visually or acoustically detected.

Moreover, the 80th session of the Marine Environment Protection Committee (MEPC), agreed to designate a particularly sensitive sea area in the North-Western Mediterranean Sea (NW Med PSSA) to protect cetaceans from international shipping. The designation includes associated protective measures (APMs), which are recommendatory and intended to be by any commercial ships and pleasure yachts from 300 gross tonnage and upwards:

  • Mariners should navigate with particular caution within the NW Med PSSA, in areas where large and medium cetaceans are detected or reported, and reduce their speed to between 10 and 13 knots as voluntary speed reduction (VSR). However, a safe speed should be kept, so that proper and effective action can be taken to avoid collision and any possible negative impacts on the ship’s maneuverability.
  • Mariners should keep an appropriate safety distance or speed reduction measure from any large and medium cetaceans observed or detected in close-quarter situations. The safety distance or speed reduction measure should be adapted to the actual navigation circumstances and conditions of the ship.
  • Mariners should broadcast on VHF or other available means on scene, the position of medium and large cetaceans observed or detected within the designated PSSA and transmit the information and the position to a designated coastal Authority(ies).

Current Scenario 

Ultimately, the multifaceted approach involving technological innovations, adherence to regulations, and collaborative efforts between authorities and the shipping industry is crucial to reducing ocean roadkill and ensuring a safer environment for marine animals.

The fate of these magnificent creatures lies in our ability to balance maritime activities with responsible conservation measures, fostering a harmonious coexistence between humanity and the diverse life inhabiting our oceans.

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Source: Safety4sea