A new paper has shared findings that the most prevalent cause of ceacens strandings is the little understood threat, ship strike.
Last month a new paper was published sharing findings that the most prevalent cause of cetacean strandings in France is ship strike. In recent decades’ marine traffic has increased and is expected to continue rising as global demand for goods grows alongside population growth. Collisions with vessels have become a significant cause of death for cetaceans; however, it’s uncertain just how many whales die each year around the world from this threat. Many carcasses are lsot at sea, falling into the depths to feed deep-sea creatures, and very few whales will be brought into the coast. Due to this, and the unlikelihood of vessel crews noticing a strike, especially from a large vessel, ship strikes are expected to be severely underreported. In some cases, whales have been brought into port draped over the bow of vessels.
Monitoring of marine mammal strandings remains one of the most effective ways to monitor just how bad this problem really is. A nationally coordinated network in France has been collecting data and samples on stranded marine mammals since 1972, along the Mediterranean and Atlantic French coasts. The strandings data, including photographs and necropsy (autopsy of animals) reports collected up until 2017, has now been examined with the hope of providing a review of confirmed collision records of large whales in France. During the 45-year period, a total of 51 ship strike occurrences were identified which was the most common cause of mortality for large whales in France. The findings show that since 1972 there has been an increase from just seven records identified during the first decade, to 22 stranded animals observed between 2005 and 2017. The rate of ship-struck animals in the Mediterranean Sea is even more worrying, with one in five stranded whales showing signs of ship strike. This study highlights the threat ship strikes may pose to European whale populations. The true rate of ship strikes is still unclear; however, the prevalence of evidence in stranded specimens along the French coast suggests that it may be of significant conservation concern. The European Marine Strategy Framework Directive requires Member States to achieve Favourable Conservation Status for marine mammal populations, and pressures including ship strikes threaten that.
ORCA is continuing research into ship strike to try and identify what can be done to prevent this threat from occurring and provide a solution to ships crews and policy makers to implement solutions in the Bay of Biscay, and beyond. Last week the research continued with ORCA’s Science Officer, James Robbins, boarding the Brittany Ferries Pont-Aven to try and gain valuable insights into this threat. Using high quality equipment, James hoped to record and observe fin whale’s behaviours when faced with large ships in the Bay of Biscay. Some of the footage captured during the research can be seen here, which shows a mother and calf pair as the vessel continues along its path. Mother and calf pairs are expected to be particularly vulnerable to ship strike, and these videos will add useful data to our on-going study which will also be the focus of a PhD at Portsmouth University, starting in October.