Collisions between ships and whales can pose a significant threat to the survival of some whale populations. The lack of robust and holistic assessments of the consequences of mitigation solutions often leads to poor compliance from the shipping industry. To overcome this, several papers support a regulatory approach to the management of whale-ship collisions through the International Maritime Organization (IMO), the UN agency responsible for maritime affairs. According to the IMO risk assessment approach, in order to compare the costs of implementing mitigation solutions and their benefits, there is a need well-defined risk evaluation criterion. To define a risk evaluation criterion for whales, we have used an ecological-economic framework based on existence values and conservation objectives. As an illustration, we applied our framework to the Mediterranean fin whale (Balaenoptera physalus) population and determined the cost of averting a whale fatality as a proxy for the societal benefits. More precisely, we have estimated a ‘Value of averting a Mediterranean fin whale fatality’ of 562,462 (in 2017 US dollars); this corresponds to 637,790 USD when converted to 2021 US dollars. The societal benefits of solutions that reduce the risk to whales could therefore be weighed against the costs of shipping companies to implement such measures. This can lead to assessments that are more transparent and the introduction of mandatory measures to reduce ship strikes.