The recent humpback whale sighting in the Shannon Estuary caused quite a lot of excitement both inside the IWDG office and with the public. People travelled from all over Clare and beyond with their binoculars to see our new neighbour. The IWDG used their RIB to collect as much information as possible, including length and body condition.
A peculiar occurrence and a first in Irish recorded history, a whale in the Shannon Estuary1.
Amongst all the excitement and wonder, concern for the whale’s safety quickly grew as it is not alone in the Shannon Estuary. The Shannon is a busy waterway for large cargo ships carrying thousands of tonnes of material to and from Ireland via Moneypoint, Aughinish, Foynes and Tarbert all under the watchful eye of the Shannon Foynes Port Company. In addition, the Shannon Ferry makes constant crossing from Tarbert to Killimer and pleasure boats also enjoy the waters. Although the river appears very broad, a recent discussion with Shannon pilot, Patrick Galvin, highlighted that large ships are limited in their movements by sand banks, rocky outcroppings and the shallow slope of the shore. The constantly changing tides add to these complications, limiting their manoeuvrability, especially for the large cargo ships. Highly trained pilots and no-nonsense crews run a tight ship while traversing the Shannon Estuary, ensuring the safety of everyone on the water. However, they have never had to worry about sharing these densely travelled waters with a whale before, and these deeper channels would be particularly attractive to a feeding whale.
A recently published paper 2 highlighted ship strikes as the primary threat for large whales globally since the near total elimination of whaling. Approximately 90% of all our goods worldwide are transported on boats across large shipping lanes, many of which pass right through critical whale habitats and hot spots. Whales, especially calves and juveniles, are at risk of being struck when spending time at the surface. The injuries can often be horrific, such as broken skulls, amputated jaws and severed tails, which ultimately result in the animal passing away 3.
Loosing whales to ship-strikes is not only catastrophic to the whale population, it also has long lasting impacts on our ocean’s ecosystem. Large whales are key in maintaining a healthy ecosystem. In life they exert top-down control by feeding on large schools of krill, producing nutrients through defecation and resurfacing nutrients by diving. These nutrients facilitate the bloom of phytoplankton, which captures tonnes of carbon and produces oxygen. In death they sink to the ocean floor, providing nutrients for deep sea bottom dwellers and storing carbon in the sea floor. Without them, the ocean capacity to regulate itself and capture carbon declines drastically. With every large whale killed by a ship strike, it can take decades for them to be replaced due to their slow reproductive rates, including late maturity and long periods of parental care. Many whale populations still suffer from previous over-exploitation and the unsustainable rate of loss due to ship strikes could result in local extinctions.
Unfortunately, the issue of ship-strikes is complex and multifaceted with no clear-cut solution to fully eliminate the problem. However, several measures have been proven to be effective and are being adopted globally to preserve and recover whale populations. Research shows that mortality rates drop drastically when vessels do not exceed 10 knots and skyrocket once the ship is travelling at 14 knots or more. Therefore many countries have implemented seasonal speed restrictions during key times for whale populations, or in important habitats, such as breeding seasons or on their core feeding grounds.
Early detection of a whale has been instrumental in avoiding collisions, however in rougher weather conditions this becomes tricky. Whales remain low in the water, with their blows (the exhale) often missed when winds are high. Visual observation also becomes impossible during the night, in fog or in heavy rain. Recent technological advancements have provided mariners/researchers with alternative, which the IWDG is actively involved in developing.
The IWDG are directly involved with two separate EU-funded projects on mitigating ship strikes using technology. The Atlantic Whale Deal 4,5 uses cutting-edge technology such as satellite imagery, acoustics and thermal cameras to develop an early warning system for mariners. Under this project, the IWDG is using thermal cameras to capture video of large whales in the Northeast Atlantic, which can be used to train and validate an AI capable of detecting whales in adverse weather conditions, during the night and at a distance people might not be capable of. Using this technology, mariners will be warned ahead of time of the presence of whales, allowing them to slow their vessel or take evasive manoeuvres when appropriate.
For Ocean, which is a Horizon 2020 funded project 6,7, the IWDG has been developing a new reporting app to reduce collision risks at sea. Mariners will be able to download the app in the new year, empowering them to report whales and containers in real time, alerting other navigators to the potential collision risks and improving overall marine safety.
The IWDG has been in regular communication with the Shannon Foynes Port Company regarding the presence of the humpback whale in the Shannon Estuary, advising them on the benefit of a temporary speed restriction (10 knots), requesting vigilance during their operations and encouraging sightings are to be reported back to the IWDG. It is our hope to protect this humpback whale against potential ship strike and set a positive president of proactive mitigation in case this is not a sole occurrence. Ireland is known as a feeding ground for humpback whales, with some younger individuals overwintering in Irish coastal waters, rather than migrating to West Africa or the Caribbean for breeding. As the population grows, it is possible that this is not the last whale seen feeding in the Shannon Estuary. It is our duty to ensure their safety in our waters.
Emilie De Loose
Links
1Link to information on the Shannon Humpback Whale: https://iwdg.ie/humpback-whale-in-the-shannon-estuary/
2 Link to the journal discussing recent article (article is behind a pay wall): https://www.washington.edu/news/2024/11/21/whale-ship-collisions/
3 Heart breaking article about recent ship strike on a humpback (warning graphic): https://www.dailymail.co.uk/sciencetech/article-13967957/Humpback-whale-named-Sweet-Girl-disfigured-ferry.html
4IWDG page on the Atlantic Whale Deal: https://iwdg.ie/atlantic-whale-deal/
5Atlantic Whale Deal project page: https://www.atlanticarea.eu/discover-our-projects/approved-projects/atlantic-whale-deal
6 IWDG page on the Ocean Horizon Project: https://iwdg.ie/iwdg-are-partners-in-major-eu-ocean-project/
7 Ocean project page: https://ocean-navigation-awareness.eu/
