Lough Hyne, a truly spectacular saltwater lake, spans a distance of one kilometre in West Cork, not far from Skibbereen. Home to a vast array of both flora and fauna, including 72 different species of fish (1)—some of which are very rare—it is no surprise that the lough became Ireland’s first marine nature reserve in 1981 (2).

Lough Hyne in County Cork

The unique habitat that the lough provides is dependent on the tidal channel that funnels in from the Atlantic Ocean twice a day (named the rapids). Water can reach speeds of 3m/s through the rapids into the Lough, creating important habitat through its differing speeds (3).  As well as the ecosystem services provided by the lough, it is also a place of great natural beauty that has been enjoyed by people for hundreds of years, inspiring poetry and paintings alike. It is a place rooted in Irish folklore, forming the backdrop for the tale of the ancient chieftain who had the ears of a donkey (4).

Lough Hyne Habitat

Lough Hyne is special because it is comprised of saltwater and receives very little freshwater throughout the year. The tides in the lake are controlled by the rapids, and its salinity is very similar to that of the ocean. It also has sand dunes, beaches, and cliffs nearby. Low lying hills encompass the lough, providing further habitat as well as beautiful surroundings to the area (5).  Its unusual conditions (sheltered and calm, with not much light penetrating through) mean that in shallower areas, marine life is similar to that found in rock pools. As it gets deeper, marine life changes and becomes even more fascinating, with creatures existing at depths they never would elsewhere.

Marine life 

The marine life of the lough as a whole is diverse and interesting, with 75% of all species in Ireland represented there (6). One example is the sea sponges that are found there, which have been studied extensively. Their numbers dramatically started dropping between 2010 and 2015, for reasons that are still unclear (7). Fortunately, the growth of new sponges in the lough has been seen in more recent years (8). Research has been carried out at Lough Hyne for many years, with the first study being carried out in 1886, on the purple sea urchin (3). Today, studies of the rich biodiversity in the lough are still being carried out, with University College Cork funded research facilities close by.


Bioluminescence in Lough Hyne, taken from Roaringwaterjournal.com

Lough Hyne is also an excellent location for walking, swimming, and kayaking. A particularly special activity at the lake is the night-time kayaking sessions which are run between April and October, the perfect time to observe the bioluminescence in the lake. Bioluminescence is the sparkling blue light that can be seen in the water and is caused by chemical reactions inside the bodies of organisms such as plankton that live in the lake. It makes for a jaw dropping sight, but this phenomenon has a purpose other than being aesthetically pleasing. Bioluminescence is used by marine organisms for several purposes, namely as a defence mechanism (9). Of course, it is most widely appreciated for its beauty—however other ways that it can be used have also become of interest, such as current research into the development of bioluminescent trees, reducing the need for streetlights (9).

Climate change impacts

As our climate continues to change, it is highly likely that Lough Hyne and other habitats in Ireland will be irrevocably changed. Increasing temperatures will lead to warmer water in the lough, which will affect the types of marine life that make Lough Hyne so unique—for example, some types of plankton prefer colder temperatures, and will inhabit the lake in much smaller quantities in warmer years (10). 

It is so important that we strive to prevent climate change from worsening, so that our beautiful landscapes and habitats such as Lough Hyne continue to be protected, and its incredible marine life and bioluminescence events can be enjoyed for many years to come. 

By Eve Moore, MSC Sustainable Environments


  1. Discoveringireland.com. 2022. Lough Hyne, Skibbereen, West Cork | Lough Ine. [online] Available at: <https://www.discoveringireland.com/vacations/lough-hyne/> [Accessed 28 August 2022]. 
  2. Ireland’s West Coast. 2022. Lough Hyne. [online] Available at: <https://www.thewildatlanticway.com/waw/lough-hyne/> [Accessed 28 August 2022].
  3. University College Cork. 2022. Lough Hyne | University College Cork. [online] Available at: <https://www.ucc.ie/en/bees/research/loughhyne/> [Accessed 28 August 2022].
  4. Irish Examiner. 2022. Islands of Ireland: Death of a chieftain at Lough Hyne. [online] Available at: <https://www.irishexaminer.com/property/homeandgardens/arid-30898794.html> [Accessed 28 August 2022].
  5. Kitching, J., 1987. Ecological Studies at Lough Hyne. Advances in Ecological Research, pp.115-186.
  6. Discoveringireland.com. 2022. Lough Hyne Nature Reserve County Cork. [online] Available at: <https://www.discoveringireland.com/lough-hyne-county-cork/#:~:text=The%20sea%20life%20in%20Lough,of%20crab%20crawl%20the%20waters> [Accessed 28 August 2022].
  7. Silicon Republic. 2022. How a west Cork lough is offering a window to the changing ocean. [online] Available at: <https://www.siliconrepublic.com/innovation/lough-hyne-west-cork-deep-sea-marine-research> [Accessed 28 August 2022].
  8. Bell, J. and Micaroni, V., 2021. Meet the 1,850 animals and plants we found in Cork’s Lough Hyne. [online] RTE.ie. Available at: <https://www.rte.ie/brainstorm/2021/0610/1227287-lough-hyne-marine-nature-reserve-west-cork/> [Accessed 28 August 2022].
  9. Education.nationalgeographic.org. 2022. Bioluminescence. [online] Available at: <https://education.nationalgeographic.org/resource/bioluminescence> [Accessed 28 August 2022].

Researching the impact of climate change on Lough Hyne. 2022. Cork: UCC Ireland.