Marine Institute

Benthos Ecology Group

The Benthos Ecology Group is responsible for the review and assessment of existing and proposed activities that may have an influence on the marine environment and advising on likely consequences particularly as they relate to licensing  of activities on or near the seafloor.  

The organisms living on and in the seafloor are a good indicator of stresses on the marine environment and therefore, can act as an early warning system. These stresses can originate from natural and/or anthropogenic sources. For example, organic matter falling to the seafloor from fish-farm operations may increase oxygen demand in the vicinity and stress and/or kill organisms located therein. Surveys using a variety of methods and devices have been used to:

1. assess natural or baseline conditions prior to the commencement of a development or activity,

2. determine the conservation status of an area or,

3. to monitor sea bed health as part of coordinated sampling programs (e.g. WFD ).

Activities Requiring Benthos (macro-invertebrate) Surveying

1.Water Framework Directive 

Benthic macro-invertebrates is one of the biological quality elements for monitoring transitional and coastal waters under the WFD. A comprehensive benthic sampling programme is carried out in targeted water bodies once every three years. The data is analysed using an index of invertebrate quality (IQI) developed jointly by the UK and Ireland and reported to the EPA  for national assessment. 

2.Natura Assessment

Different marine communities have different responses to a variety of pressures. Our work in this field is to carry out risk assessments of both aquaculture and fishery activities on habitats and species of particular conservation importance and provide advice to DAFM  on licensing of these activities. 

3.Dumping at Sea 

Activities that remove large amounts of sedimentary material from one marine area, such as maintenance dredging of shipping ports and navigation channels, are generally discarded in other marine areas, if an alternative use cannot be found. The spoil area will typically require an extensive benthic survey to determine if no particularly sensitive habitats or species are found at the sites and to provide a baseline set of data that might be referred to in subsequent monitoring programs. 

4.Finfish Aquaculture

Finfish farming (salmon and trout) are carried out along the seaboards of Ireland. These activities result in inputs to the marine environment in the form of wasted feed and faecal material. This organic rain falls to the seafloor and can result in stress on benthic environment. As a result, aquaculture operators are responsible for monitoring the benthic environment with a view to minimising the impact. We review these reports to ensure that they comply with standard protocols:

Benthic Monitoring Protocols

In May 2000, the Department of Marine and Natural Resources implemented a series of Protocols to monitor fish farming activities in Ireland. An annual benthic monitoring survey forms a part of these protocols, which was revised in 2008. The surveys are conducted to ensure operations are not having an undue impact on the seafloor beneath fishfarming cages. In the event of a breach of the allowable impact levels, suitable management modifications are implemented to reduce the impact and allow a suitable degree of recovery of the benthic environment. 

For further information contact:

email: francis [dot] obeirn [at] marine [dot] ie (Subject: Enquiry from Benthic web page) (Francis O'Beirn)

Telephone: +353 (0)9 138 7250