IWDG submission to Consultation on Restriction of Pair Trawling

20th Jun 2018

Consultation Paper on Minister’s Review of 

Trawling Activity Inside the 6 Nautical Mile Zone Submission from the Irish Whale and Dolphin Group

Submission by the Irish Whale and Dolphin Group


The Irish Whale and Dolphin group (IWDG) welcome the opportunity to comment on the review of trawling activity inside the 6nml zone.  We also welcome the consultation report and its examination of the wider impacts of fisheries and fisheries management including eco-tourism, wildlife conservation, habitat protection and recovery, the recovery of depleted inshore fish stocks and the socio-economic impacts on coastal communities. Healthy and diverse fish populations are essential for maintaining a rich marine biodiversity and vibrant coastal communities, and the IWDG see great synergy between effective local fisheries management and marine conservation.

Irish Whale and Dolphin Group

The Irish Whale and Dolphin Group is an All-Ireland group “dedicated to the conservation and better understanding of cetaceans (whales, dolphins and porpoises) in Irish waters through study, education and interpretation”. The IWDG co-ordinate All-Ireland cetacean stranding and sighting schemes and the data is made available to support relevant research, conservation and welfare issues.  IWDG’s registered office is in the maritime heritage town of Kilrush, Co Clare.

Fishing Related Activity

The IWDG has been active in fishery related issues for many years. In 2006 we published a Commercial Fisheries Policy Document which was widely circulated within the fishing industry.  The IWDG was invited onto the Celtic Sea Herring Management Advisory Committee in 2012 as invited experts and have delivered a number of bycatch monitoring and environment management plans to the CSHMAC.

The IWDG have been concerned over the exploitation of non-quota pelagic forage fish in inshore Irish waters for a number of years. This includes the impact of removal and dispersion of large quantities of these ecologically important fish species by commercial vessels on cetaceans, and the growing eco-tourism market that relies on them. Our main concern lies chiefly with sprat Sprattus sprattus. Commercial fishing of these ecologically important pelagic forage fish is unregulated and non-quota, despite the lack of any research on the basic ecology of the species involved or the sustainability of this fishery.

Other pelagic forage species such as sandeels (Ammodytes tobianus) are also of concern. While sandeels are not fished commercially in Ireland yet, the current growth of the fishmeal and fish derived nutritional supplement industry in Ireland is likely to lead to future pressure on sandeels and other non-quota fish species.. Almost all predators in Irish waters will feed on sandeels at some point, including fish, seabirds and marine mammals. To certain species of fish, such aspollock and mackerel, sandeels are a vital part of their diet. 


Cetaceans in Irish waters

To date 25 species of cetacean (whales, dolphins and porpoise) have been recorded in Irish waters. Some of these are rare or vagrants, some are resident, occurring all year around while others are seasonally present passing through our waters or moving between Ireland and feeding and/or breeding grounds. The status of most species or populations is not known.  The small resident population of bottlenose dolphins in the Shannon Estuary appears stable within the power of the monitoring protocol to detect change.

The numbers of fin and humpback whales, seem to be increasing in Ireland.  These species have been protected from whaling, which was the principle cause of their decline, since 1986 and populations appear to be recovering. An increase in the number of sightings of these two species has been recorded, especially in coastal waters (Whooley et al. 2011; Ryan et al. 2015). Their presence in inshore waters is directly linked to the availability of small forage fish.

This increase is positive and provides significant opportunities for marine ecotourism and whale-watching in Ireland, especially in peripheral coastal communities.


Importance of pelagic prey to cetaceans

Pelagic schooling fish such as herring and sprat are an important prey species for many species of cetacean. Although the diet of many cetaceans in Ireland is poorly known, recent research, supported by the IWDG, on the diet of fin and humpback whales in the Celtic Sea showed herring and sprat to be of great importance to their diet. Results show that sprat and herring, especially young fish (year class 0-1), are important prey for humpback and fin whales in the Celtic Sea during the autumn and winter (Ryan et al. 2014; Volkendant et al. 2015). These oily pelagic schooling fish are also an important prey species for economically important quota fish species such as all members of the cod family, and valuable protected fish such as albacore and bluefin tuna.


Review of Risk Assessment of Fishing in Marine SACs

The IWDG have reviewed the report “Article 6.2 (Habitats Directive) Risk Assessment: The effects of fisheries on Qualifying Interests in Special Areas of Conservation in Irish coastal waters” published by the Marine Institute in 2015. The IWDG do not accept the assessment with regard to SACs with cetaceans listed as a qualifying interest.



Harbour porpoise are rarely recorded bycaught in trawl nets (Berrow and Rogan 1998; Morizur et al. 1999) though Smiddy (1991) suggested strandings in east Cork/west Waterford were associated with the herring fishery. Bottlenose dolphins likewise have not been recorded bycaught in trawl fisheries (Berrow and Rogan 1998; Morizur et al. 1999). The main area of conflict between dolphins and porpoises and trawl fisheries is the removal of potentially important prey items with subsequent impacts on foraging efficiency and fitness.

Harbour Porpoise

Knowledge on diet of harbour porpoise in Ireland is very poor with only one study published in the grey literature to date (Rogan and Berrow 1996),over 20 years ago. This study showed the most important prey were Trisopterus sp, gadoids and herring..

A study of the diet of harbour porpoise should be commissioned, potentially accessing the samples already collected  by UCC from their long term study of cetacean diet from stranded  animals or (in time) from the recently established Necropsy Scheme funded by the Marine Institute. Studies elsewhere have shown considerable local variation and diet studies targeting sites and regions containing SACs would be particularly useful.

Abundance estimates from SACs and surrounding waters are available and need updating to explore trends. Clearly the harbour porpoise in designated SACs are part of a much wider population and more knowledge on movement patterns and local distribution, especially in relation to fishing effort would be very useful.

Risk of environmental impact from trawling

Marine Institute (2015) state “Porpoise feed on small fish including sandeels and juvenile gadoids and clupeids. Biomass of these stocks in coastal and continental shelf waters will determine prey availability to common porpoise. In RWBay and the Blasket Is habitat quality is related to the availability of suitable prey within the sites. High fishing effort and local depletion of stocks would in that case be contrary to the conservation objective targets. Depletion is more likely or possible for stocks that are locally distributed rather than migratory stocks such as herring, sprat and mackerel. Migrating pelagic stocks provide a seasonal and temporary pelagic subsidy into SACs designated for Harbour Porpoise. The relative importance of this subsidy versus local fish production in maintaining habitat quality within the sites is unknown”. IWDG endorse this statement and thus restricting fishing effort within 6nmls and baselines and carrying out a proper assessment of the role of pelagic and demersal species in the diet of harbour porpoise is essential. More research also needs to be conducted on site fidelity of sprat and herring aggregations as there is scientific and anecdotal evidence to suggest that once fished out, aggregations of these species, local to particular bays and coastal areas, do not readily recover. This site fidelity makes the potential impact of overfishing of pelagic prey species within SACs particularly worrisome.

Marine Institute (2015) acknowledge harbour porpoise are vulnerable to bycatch in static gillnets and list a number of studies which reported no or little bycatch in the Blasket Islands SAC. IWDG acknowledge bycatch is probably a rare event but support ongoing initiatives to record bycatch as part of Data Collection Framework (DCF) programmes.  Consideration should be made to use onboard cameras on small vessels fishing within SACs with the full support of fishers to provide good observer coverage.

Blasket Islands SAC

At present no pelagic trawling takes place within the SAC boundaries but it could in future if Celtic Sea Herring stocks increase or fisheries for sprat, sandeels or other important prey items develops. The MI statement that “It is unlikely that pelagic fish accumulate or shoal to any great extent within the Blasket Is SAC” is unsubstantiated and not accepted.  IWDG do agree that “Pelagic fishing in Dingle Bay and demersal trawling in the surrounding area may reduce prey availability in the area” but do not accept “Commercially targeted fish are however larger (and less abundant) than the size classes selected by porpoise” as a detailed study of their diet is not available.

Roaringwater Bay and Islands SAC

The MI state “Fishing for sprat and herring occasionally occurs in the site but most pelagic effort occurs between 20-50km to the south”, but we understand limited fishing for herring occurred most years when the Celtic Sea herring Standing Stock Biomass (SSB)  was greater on the boundary or just outside the SAC. Certainly, fishing occurs much closer than 20-50km south.

Bottlenose dolphin

It is acknowledged that “Bottlenose dolphins have highly flexible foraging tactics and local populations may develop original feeding tactics or techniques”.  The MI state “Resident BND in Doubtful Sound, New Zealand feed mainly on fish associated with reef and have a low dependence on pelagic fish migrating in and out of the area (Lusseau and Wing 2006)”. They also state “Resident populations of BND have a low dependence on pelagic subsidy i.e. pelagic fish migrating in and out of their habitat (Lusseau and Wing 2006).” This reference used to dismiss pelagic prey as a food source was based on stable isotope analysis of 11 slough skin samples collected in New Zealand! It is not directly applicable to the Shannon Estuary as it involves a study from very different habitat and prey types. The only published study of the diet of bottlenose dolphins in Ireland (Milian et al. 2015) showed a total of 37 prey taxa were identified, suggesting that bottlenose dolphins have a broad diet, with the main prey items identified as five gadoid species. Bottlenose dolphins have been described as generalist predators feeding mainly on pelagic fish and squid prey, including demersal species and some pelagic prey (Santos et al., 2001, 2007; Spitz et al., 2006), the relative importance of oil rich seasonally available pelagic forage species to the diet, body condition and reproductive success of the bottlenose dolphin population in the Shannon Estuary has not been assessed, and the contribution of data from stranded animals from this population to existing dietary studies is likely minimal

A study of the diet of bottlenose dolphins, especially in the Shannon estuary is badly required. This should include the distribution and abundance of potential prey and diet using stable isotopes and observations, given that stranded animals are very rare.

Lower River Shannon SAC

It is useful to state that the genetically discrete population inhabiting the Shannon Estuary and adjacent Brandon and Tralee Bays comprises 145 extant individuals (Levesque et al. 2016; Baker et al. 2018). Thus it is highly vulnerable due its relative small population size and limited distribution. Bottlenose dolphins in the Shannon Estuary have been observed feeding on pelagic prey such as mackerel, and garfish (Ingram 2000; Baker 2017).

The MI state “There is a winter pelagic trawl fishery for sprat in the Shannon Estuary. This fishery occurs within critical habitat identified for BND in the Shannon Estuary. However landings are infrequent. Landings of sprat from ICES statistical rectangles 33E0 and 34E0, which encompasses the Shannon estuary, Tralee Bay, inner Dingle Bay and the Clare coast, between 2003 and 2012 varied from 0-160 tonnes annually. The fisheries exploitation rate on sprat is unknown”. The MI also state “The infrequent sprat fishery, with landings of 0-160 tonnes per annum along the Clare and Kerry coasts is unlikely to significantly affect Shannon estuary BND. In one week in autumn 2017 two pair trawlers removed an estimated 500 tonnes of sprat from within the Lower River Shannon SAC, which is far in excess of that estimated annual removal from the Shannon. Fishing was also recorded off Moneypoint which is one of the two critical feeding habitats in the Shannon Estuary for bottlenose dolphins (Ingram and Rogan 2002).

The MI statement that “Local resident populations of BND do not rely on the food subsidy provided by immigration of pelagic fish, do not specialize in feeding on shoaling fish and take individual prey that are larger than sprat (16cm)” is not supported by data or peer reviewed references..  The importance of sprat and other pelagic schooling fish in the diet of bottlenose dolphins in the Shannon Estuary SAC has not been assessed, nor has the importance of sprat in sustaining populations of gadoid species in the estuary, which form the main diet of bottlenose dolphins.

Given the uncertainty about the role of pelagic prey in the diet of qualifying interests in SACs, the IWDG propose a moratorium on all trawl fishing in Special Areas of Conservation which include cetaceans as a qualifying interest until a full and proper assessment is carried out on the potential effects of removal of large quantities of potential prey on SAC conservation objectives. These include Roaringwater Bay, Blasket Islands, Rockabill to Dalkey Island, Lower River Shannon and West Connacht SACs. An assessment should include the importance of pelagic and demersal fish in the diet of harbour porpoise and bottlenose dolphin (both commercial and non-commercial fish species) and the use of the SAC at the individual and population level.


Marine Ecotourism

Marine wildlife ecotourism is growing rapidly in Ireland. This includes whale watching and seal watching. Many boat eco-tours on offer are generic and combined with scenic coastal cruises, but the number of dedicated whale watching activity providers is growing, especially off the south coast. Marine ecotourism can diversify the income base for coastal communities and inshore fishers, and in some locations be a significant source of revenue.  Whale watching potential peaks in the winter providing important opportunities to extend the tourist season in many areas.

Marine ecotourism requires proper coastal management and the opportunity to limit large trawlers to outside 6nmls is important as the majority of marine tourism vessels operate within this range. Any enhancement to the richness and biodiversity of our coastal marine ecosystems will reap benefits for eco-tourism providers such as whale watch operators, dive boats and sea safari providers. Consideration of the requirements of important predators such as whales, dolphins, seals, and seabirds are essential for proper management and a growing marine eco-tourism sector. This should include data on numbers, diet and residency times in a location.

IWDG recommend an assessment should be made of the value of forage fish landed (which essentially go for low value processing such as fishmeal) compared to the value of marine ecotourism to vessel operators and the local economy in terms of overnight stays, food, accommodation, transport etc. to inform the management of forage fish fisheries.


Fisheries Management

Sprat has grown as a target species, especially off the south and southwest coast in recent years as due to demand for fish meal for the finfish aquaculture sector, and development of a processing plants for fishmeal and fish derived nutritional supplements. This fishery is unregulated despite the importance of these keystone species as a food source for resident and migratory cetaceans of international importance, including porpoise, dolphins, large whales and seabirds. All these species are protected under European law which requires Ireland to maintain these populations at favourable conservation status, which includes protecting their “habitats” and “future prospects”.

The IWDG call for an immediate moratorium on sprat fishing off the south and west coasts of Ireland until sufficient scientific research allows for proper sustainable management of this fishery, while also taking into account their importance as a keystone species in the marine food chain.  

An ecosystem approach to fisheries management should adopt a precautionary approach in the absence of appropriate research to inform sustainable management.




  1. The IWDG support the proposal to restrict vessels >18m from fishing within the 6nmls and baseline.
  2. The IWDG would also support the proposal to restrict vessels >15m from fishing within the 6nmls and baseline, as the reduction in fishing pressure would potentially have significant benefits for the recovery of inshore seabed habitats and coastal fish species.
  3. The IWDG propose a moratorium on all trawl fishing in Special Areas of Conservation which include cetaceans as a qualifying interest until a full and proper assessment is carried out on the potential effects of removal of large quantities of potential prey and on conservation objectives. These include Roaringwater Bay, Blasket Islands, Rockabill to Dalkey Island, Lower River Shannon and West Connacht SACs. An assessment should include the importance of pelagic and demersal fish in the diet of harbour porpoise and bottlenose dolphin (both commercial and non-commercial fish species) and the use of the SAC at the individual and population level.
  4. The IWDG propose a moratorium on all sprat fishing both inside and outside the 6nml limit and baseline until a management plan for this species is put in place, supported by robust science including the setting of quotas based on sustainable fishing and best practice. This assessment should include information on spawning and nursery areas, local stock structure and movements.
  5. The IWDG further propose that a precautionary moratorium on fishing for other non-quota pelagic forage species is put in place until such a time that those species (e.g. sandeel) have management plans put in place, supported by robust science including the setting of quotas based on sustainable fishing and best practice. This assessment should include information on spawning and nursery areas, local stock structure and movements.



Baker, I. (2017) Life history, behaviour and social structure of bottlenose dolphins (Tursiops truncatus)  in the Shannon Estuary, Ireland. Dissertation, Galway-Mayo Institute of Technology, Galway, Ireland

Baker, I., O’Brien, J., McHugh, K, and Berrow, S. (2018) Female reproductive parameters and population demographics of bottlenose dolphins (Tursiops truncatus) in the Shannon Estuary, Ireland.  Marine Biology.

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Ingram SD (2000) The ecology and conservation of bottlenose dolphins in the Shannon Estuary, Ireland. Dissertation, University College Cork, Ireland

Ingram, S and Rogan, E. 2002 Identifying critical areas and habitat preferences of bottlenose dolphins Tursiops truncatus. Marine Ecology Progress Series 244: 247-255

Levesque, S., Reusch, K., Baker, I., O’Brien, J. and Berrow, S. (2016) Photo-Identification of Bottlenose Dolphins (Tursiops truncatus) in Tralee Bay and Brandon Bay, Co. Kerry: A Case for SAC Boundary Extension. Biology and Environment: Proceedings of the Royal Irish Academy 2016. DOI: http://dx.doi.org/ 10.3318/BIOE.2016. 11

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Santos, M. B., Pierce, G. J., Reid, R. J., Patterson, A. P., Ross, H. M., & Mente, E. (2001). Stomach contents of bottlenose dolphins (Tursiops truncatus) in Scottish waters. Journal of Marine Biological Association of the United Kingdom, 81(5), 873-878. http://dx.doi.org/ 10.1017/S0025315401004714

Smiddy, P. (1991) Common Porpoise (Phocoena phocoena (L.) Ir. Nat . J. 23(12) 496.

Spitz, J., Rousseau, Y., & Ridoux, V. (2006). Diet overlap between harbour porpoise and bottlenose dolphin: An argument in favour of interference competition for food? Estuarine, Coastal and Shelf Science, 70(1-2), 259-270. http://dx.doi.org/10.1016/j.ecss.2006.04.020

Volkenandt, M., O’Connor, I. Guarini, J-M., Berrow, S and O’Donnell, C., (2015) Fine-scale spatial association between baleen whales and forage fish in the Celtic Sea. Canadian Journal of Fisheries and Aquatic Science. 10.1139/cjfas-2015-0073.

Whooley, P., Berrow, S. and Barnes, C. (2011) Photo-identification of fin whales (Balaenoptera physalus L.) off the south coast of Ireland. Marine Biodiversity Records. Volume 4e8, 1-7.



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