chapter title 15 2. MARINE BIODIVERSITY Brittlestars. Ophiothrix fragilis, Red Bay, Co Antrim Key messages • More than half of Northern Ireland’s What is biodiversity? biodiversity is found beneath the sea. Biodiversity (biological diversity) is a term • Northern Ireland has a rich marine used to describe the variety of life found in biodiversity due to its position at a junction the environment including plants, animals and of cold northern and warm southern waters. micro-organisms, the genes that they contain • Many of our marine species and habitats are and the ecosystems that they form. considered to be in a good state. • Some important marine habitats have been It is a little known fact that approximately 50% damaged by mobile fishing gear. of Northern Ireland’s biodiversity lies below • The Northern Ireland Government the sea, largely regarded as out-of-sight and Departments have a responsibility to restore out-of-mind (1). Simply put, marine biodiversity damaged habitats to favourable condition. concerns the whole variety of life found in • Enhanced protection of marine biodiversity our seas and oceans, from the largest whales will be delivered through the Northern to the smallest bacteria. Most importantly, Ireland Marine Bill by designating Marine marine biodiversity plays a fundamental role in Protected Areas. maintaining the balance of life on our planet. • More marine monitoring and research is required to understand the complex marine What do we know about marine biodiversity environment fully. in our own seas? • There is an important role for coastal The first recorded survey of Northern Ireland’s communities in biological recording; rich marine biodiversity dates back to 1790 research is not solely the preserve of when systematic dredging of the seabed government agencies and can be carried out was being conducted by the naturalist in partnership with volunteers. John Templeton. Many other notable local • The effects of climate change may be scientists followed in his footsteps forming detected through monitoring changes in institutions such as the Belfast Natural History species composition and distribution. and Philosophical Society. In the 1980s diving surveys were carried out by the Ulster 16 state of the seas Museum, supported by the DOE. These Birds (RSPB) West Light Seabird Observatory. showed that the seas around Northern Ireland Our sheltered sea loughs host internationally support a very diverse range of seabed habitats important flocks of overwintering wildfowl as and associated biological communities. well as important tern colonies. Around most of the coast it is possible to have an encounter Northern Ireland is located at a junction with seals, whales and sharks. Occasionally, between southern warm water ‘Mediterranean rare marine turtles are also observed in our Lusitanian’ species and cold water ‘Arctic waters. Boreal’ species. These range from the very diverse Rathlin sponge reef communities to Over recent years there has been much fantastic large underwater sand formations press interest in the apparent increase in just off the Giant’s Causeway and from tide- observations and migrations of rare warm swept gravels adjacent to Torr head at the water species such as trigger fish Balistes north entrance to the Irish Sea to the Red capriscus, spiny crayfish Palinurus elaphus, Bay maerl Lithothamnion and Phymatolithon sun fish Mola mola, and jellyfish such as the species (coralline seaweed) beds through to mauve stinger Pelagia noctiluca. As yet, it is the sheltered mud communities in the upper not clear whether these events are attributable reaches of our unique sea loughs. to warming seas or simply a reflection of enhanced reporting. The offshore gravels of the North Channel and deep muds of the north-west Irish Sea have One of the main natural factors influencing the been monitored by NIEA and AFBI for over 15 range of habitats and species are the strong years. Over 700 invertebrate taxa have been tidal forces that sweep our local waters. These recorded and analysis of the results indicates present considerable challenges for marine that the area has remained stable over recent biologists engaged in research and monitoring times. Furthermore, the Atlantic oceanic waters at sea. Strangford Lough Narrows, for example, influenced by the Gulf Stream and the variable has currents as strong as 9 knots which can water types of the Irish Sea, have contributed only be dived for a short period in every 12 to the diverse range of habitats found in hour tidal cycle. At this location, the habitat is these waters. This makes Northern Ireland mainly tide-swept bedrock which is extremely an important site for monitoring the impacts biologically diverse. of climate change, particularly in relation to changing seawater temperatures (http://www. Human activities, even those which are well mba.ac.uk/marclim/index.php?sec=info). regulated, may have the potential to impact on marine biodiversity. These include marine Rathlin Island is renowned for its nesting aggregate extraction, aquaculture, dredge- seabird colonies which may be witnessed with spoil disposal, outfalls, marine renewable a visit to the Royal Society for the Protection of energy devices, marine construction, The biological diversity of a rocky reef- Rathlin Island The sponge, Axinilla dissimilis- Rathlin Island chapter title 17 Sea asparagus at Dundrum Bay commercial fishing, sub-sea cables, oil and The first comprehensive diving survey of the gas. Unregulated activities include sea angling, Northern Ireland seabed (2) reported the results marine eco-tourism, boating (anchoring), of 999 dives, detailing 730 sites and a total of diving, shoreline shellfish gathering, bait 957 different species of plants and animals. digging, horse riding and seaweed harvesting. The introduction of non-native invasive species The results were used to identify 3 marine is also important - (Chapter 3). NIEA has the Special Areas of Conservation (SAC)- Strangford lead role in marine nature conservation and Lough, Murlough Bay (Dundrum) and Rathlin delivers protection through site designation. Island. The most recent sub-littoral survey of It delivers this function through close Northern Ireland, a repeat diving survey, (3) co-operation with other organisations such as focused on the 46 Northern Ireland marine DARD Fisheries, DCAL, AFBI, Loughs Agency, invertebrate priority species using the original local universities and other non-governmental survey to select sites. A total of 322 dives organisations. were carried out. The survey found that while most priority species still exist within Northern What is the current state of our seabed Ireland, some key sites have lost species. communities? NIEA, in partnership with the Ulster Museum, While it is reassuring to note that many of continues to monitor the state and condition the sites surveyed 30 years ago are relatively of our marine biodiversity through a scientific unchanged, several habitats within protected dive survey programme. Using technology sites have been damaged and degraded. The such as high definition digital video, Remotely destruction of horse mussel biogenic reefs in Operated Vehicles (ROVs), extended range Strangford Lough resulted in warnings from the diving techniques and GPS navigation systems European Commission. A ban was introduced it is possible to record the state of marine on the use of mobile bottom fishing gear biodiversity in greater detail than was the case within the Lough. Furthermore this has been in the early 1980s. accompanied by a £1 million research project to explore methods to restore the site. 18 state of the seas been found in areas adjacent to aquaculture sites in Carlingford Lough. The Atlantic spider crab Maja brachydactyla, previously recorded on the west coast of Ireland, was not seen in Northern Ireland during the first sub-littoral survey but was recorded in significant numbers off Portrush in 2006. It has now apparently moved south, reported in Red Bay by Seasearch divers in 2009 and in Mill Bay, Larne Lough in 2010 (4). Seasearch Northern Ireland is a project which is grant- aided by NIEA and encourages amateur divers to be trained in marine biological recording and reporting http://www.seasearch.co.uk/ northernireland/Index.htm. In addition to dive and video surveys, both NIEA and AFBI study seabed communities using ‘grabbing’ techniques. This is where a fixed quantity of sediment is collected using a ‘grab’ from a boat, sieved and sorted to allow the identification of the animals present. Seabed communities are relatively immobile Lion’s mane jellyfish, Cyanea capillata and are therefore subject to the environmental Further details of the project can be found at conditions in the surrounding water and http://www.qub.ac.uk/research-centres/ sediment. The type, abundance and diversity ModiolusRestorationResearchGroup/ of animals living on or in the seabed can be related to the pressures of the environment (5,6). Similar damage has also been recorded Environmental pressures can be natural, for at Rathlin Island reefs which may warrant example, the changing salinity in a rock pool further action. Dives adjacent to the Skerries or estuary. They can also be manmade, like an (Portrush), have shown that horse mussel effluent from an outfall pipe. As some animals beds that were present 30 years ago have have a relatively long lifespan they can integrate now disappeared. Ireland’s only known living the effects of the environmental conditions fan mussels, Atrina fragilis, were rediscovered over time, not just at the time of sampling. during 2007 off the east coast of Rathlin Island These animals are an integral part of the food but have not been recorded since. Northern web and provide the food source for many Ireland departments are now considering what commercial fish species (Chapter 4). further actions are required to give further protection to marine features. The biodiversity of sediment dwellers is one of the key biological tools used to assess the In other less disturbed areas of Rathlin Island, health of the marine and estuarine waters 27 species of sponge, new to science, were around our coast.