Concerns over recent expansion of the aquaculture sectors in Mulroy Bay have lead to several investigations on environmental quality within the area, including a recent report (in 2000) for the Irish Marine Institute by the Centre for Marine Resources and Mariculture (C-Mar, 2000). This study reported on changes in the physical and chemical environment within Muloy Bay over a two year data collection period, and from data collected by Marine Harvest Ireland, and related observed changes to aquaculture (notably salmon farming) outputs. The study also involved sediment bioassays using sediment collected in Mulroy Bay and a variety of test organisms to investigate whether any toxicants were present that may affect the benthic community. The current study was commissioned by the Marine Institute to draw together the results of long term monitoring of water and sediment quality, and hydrography, within Mulroy Bay collected by the Institute of Aquaculture (IoA), Stirling, on behalf of Marine Harvest Ireland since 1986. The study examines trends in the physical and chemical environment within Mulroy Bay (predominantly using IoA data) since recording began, and relates results to the present activities within the bay. The aims of the study are: • to produce a carrying capacity model for Mulroy Bay as a whole • to produce maps of waste dispersion from fish cage sites • to assess the environmental sustainability of current aquaculture activities in Mulroy Bay

The bottlenose dolphin Tursiops truncatus is a ubiquitous species found throughout the temperate and tropical oceans of the world. The bottlenose dolphin population that occurs in the Shannon is one of only six known resident European populations. Since 1994, a small dolphin watching industry has been operating in the estuary, with plans for expansion. The objectives of this were to a) assess the degree of residency of bottlenose dolphins in the Shannon; b) estimate the population size and assess the production of calves; c) examine the social structure of the population; d) study habitat use and e) examine the effects of boats on dolphin behaviour. Boat-based surveys and photo-identification techniques were used to derive a population estimate and to examine distribution and movements of individually identifiable dolphins over a two-year period. Land-based scan samples were used to examine behavioural activity and interactions of dolphins with all categories of boat traffic. Trips on dolphin watching boats examined whether these boats were interacting with the same individual dolphins on a trip, daily or weekly basis. Dolphins were recorded in all months of the year but with a seasonal peak between May and September. Many of the identifiable dolphins were resighted throughout the study indicating a high degree of residency. Using photo-identification and mark-recapture analyses, the population estimate for the Shannon is 113 dolphins (CV 0.14, 95% C.I. 94 - 161). The presence of neonatal calves only from July – September indicates that there is a marked breeding season for this population and that the area is important as a nursery area. Group sizes ranged from singletons to groups of 32 animals and while dolphins were seen throughout the study area, groups were frequently encountered in the narrow water at Kilcredaun and in the mouth of the estuary. A second area of concentrated sightings was identified further up-river around Moneypoint and Tarbert/Killimer. This group comprised a smaller number of individuals, and the re-encounter rate of these individuals in the same area suggests a degree of habitat partitioning. These dolphins may be more vulnerable to dolphin watching activities than the more diffuse numbers in the outer estuary. The influence of tidal cycle was recorded at Kilcredaun and at Killimer/Tarbert with a distinct peak in sightings in the four-hour period before low tide. The frequency distribution of association indices shows that there are few "strong" associations between individuals and supports the notion of a fluid and gregarious social structure. Dolphin watching boats were involved in 61.8% of all interactions with dolphin groups, higher than any other category of boat. At present, two operators make approximately 200 dolphin watching trips annually, carrying a total of 2,400 passengers per year. The operators are highly successful in locating dolphins (97%) and the tour boats rarely come into contact with each other on the water and generally search in different areas and watch different groups. The potential for land-based dolphin watching was examined and possible sites identified. The information from this study provides a basis from which sound conservation management strategies can be developed, in order to properly conserve the species and its habitat, to develop a sustainable dolphin watching industry and to develop/monitor other coastal zone industries such as oil and gas exploration and shipping development within the Shannon.

Many definitions of ecotourism exist, but there is an emerging consensus that it is a subset of nature-based tourism and of sustainable tourism. Ecotourism is reputed to be the fastest-growing sector of the world tourism industry, with estimates of its rate of growth ranging anywhere between 10% and 30% per annum. It is reputed to attract high spending tourists, and estimates suggest it to be ‘worth’ between $10 and $17.5 billion worldwide (Fennell, 1999). Recognising its global importance, the United Nations General Assembly has declared the year 2002 as the International Year of Ecotourism and Responsible Tourism. The focus of this document is on a particular form of ecotourism known as marine ecotourism, i.e. ecotourism activities that take place in the coastal zone, in the marine environment, or in both. While ecotourism is based on enabling people to experience the natural environment in a manner that is consistent with the principles of sustainable development, marine ecotourism is about attempting to establish and maintain a symbiotic relationship between tourism and the natural marine environment. Marine ecotourism activities may be water-based, land-based, or both. They may be formally organised or undertaken independently. They may form the basis of a specialist holiday or simply be an element of a conventional holiday. Examples of activities that could be marine ecotourism include: watching whales, dolphins, sharks, seals and other marine animals, seabird ornithology, diving and snorkelling, nature-based sightseeing trips by surface boat or submarine, rock-pooling, coastal footpath and beach walking and visiting seashore and sea life centres.

The project examined whether the seasonal closure of the traditional cod fishing grounds off Greencastle, Co. Donegal, could be an effective alternative management measure. The project was instigated by the local fishing industry and operated in cooperation between industry, the Marine Institute and Bord Iascaigh Mhara. The main objectives of the project were to demonstrate the change in yield likely to result from seasonal closure, and, to determine the pattern of movement of cod from the Greencastle fishery. Each winter from 2003 to 2005 the fishery was closed by Statutory Instrument. This was achieved with the voluntary commitment of the local industry. During this period over 13,000 cod were tagged and released by Marine Institute and BIM staff working aboard chartered fishing vessels. The closure itself provided a significant conservation benefit. During 2000-2002 50% of the Irish catch weight of cod in Division VIa (> 60% by number) was taken in the winter. The closure will therefore have markedly reduced the fishing mortality on cod that would otherwise have occurred from 2003 to 2005. As the Greencastle codling fishery is a mixed whitefish fishery, any benefits flowing from the closure are likely to have extended to other whitefish stocks. Growth was extremely variable but averaged around 17 cm per annum for cod at liberty for extended periods. During the winter tagging surveys the repeated recapture of recently tagged cod on the grounds indicated the retention of cod on the grounds during winter. Tagged cod at liberty for extended periods were subsequently recaptured on, or near the Cape grounds. This strong fidelity towards the Cape grounds during winter coupled with high growth rates may mean that a short winter fishing season, with a delayed opening, may yield a similar total weight of codling than the traditional fishery but with the catch of a reduced number of cod. Such schemes may reduce current fishing mortality rates. However, the stock status of Division VIa cod is so poor that a complete closure of the fishery is warranted. It is recommended that continuation of the project be considered as a mechanism for maintaining a closure of most of the Irish fishery, whilst simultaneously improving the quality of data available for stock assessment.

This bulletin reports on the National Sea Lice Monitoring Programme carried out by the Marine Institute in 2006. Results presented in this report are mean ovigerous sea lice levels and mean mobile sea lice levels for Lepeophtheirus salmonis and Caligus elongatus

The development of the hake fishery in the ICES Divisions adjoining Ireland displays strong similarities to the fishery for megrim; Ireland's landings of hake rose from 100t per year in 1979 to 2,000t ten years later. Most hake comes from Divisions Vllg-k. The Communities Logbook of the Irish-Spanish joint venture fleet provides a short time series. CPUE by both demersal trawl and long line declined sharply between 1985 and 1991. The second quarter is the most productive of hake landings but otherwise there is no clear seasonal pattern. Hake were sampled on a half yearly basis and the fish were aged on the otoliths with a success rate of 70%. Ages in the first half were adjusted to a birth date of 1 January. Mean lengths at age were higher than those calculated by statistical methods (Normsep.). Length frequencies indicated two age groups in the discards. Methods of capturing hake have altered over the past five years, gill nets have increased their share of the Irish catch and, in 1991, were a close second to demersal trawl. Age of recruitment to the landings is 2-4 years. Discard hake was calculated at 25-163% by weight of landings per quarter in 1991, higher values coming from small-meshed nets targeting Nephrops. Survivorship curves based on aged length frequencies of hake taken by whitefish boats provided F values of between 0.40 and 0.76. These results are high and together with sharply declining CPUE would seem to suggest the part of the stock in Divisions Vllb-c and Vllg-k is more heavily fished than the stock in other parts of Sub-area VII.

Following the discovery in 1978 of large numbers of escallops in the North Water of Mulroy Bay, a detailed study of stocks was made in 1979. Spat settled out at shell height 190 to 220 µm from late July to 9 August, greatest density was 1,390 spat per metre of 12 mm diameter blue polypropylene rope. Mean daily growth rates from August to mid October ranged from 196.6 µm failing to 17.5 µm from mid October to December. Greatest densities of adult escallops occurred near rocks at depths from 3 to 15 m. Age frequency determinations showed that settlement had occurred every year since 1967. Serious predation by Asterias rubens took place on escallop held in lantern nets. The most successful containers for growth were North West plastic trays held below 5 m depth.

Sea trout from the tidal waters of the River Moy are described on the basis of life data and scales from 1,269 specimens collected during 1974 and 1975. The mean smolt age was 2.30 years. Lengths ranged from 16.4 cm for one-year-old A type smolts to 23.9 cm for four-year-old B type fish. Two-year-old smolts increased in length by 67% in their first summer at sea. Sixteen age categories were identified and 82 % of the first spawners were finnock. The proportion of 2. + fish increased throughout the season. Correlation between mean age at first maturation and coefficient of total mortality in British and Irish sea trout stocks was demonstrated. Moy trout are short-lived in the sea and this factor is identified as the most important of those influencing the population which is a typically westem seaboard Atlantic-feeding stock.

Biological characteristics of sea trout exploited in the rivers Bride (Co. Waterford) by angling and Feale (Co. Kerry) by draft net are described from small collections of scales and life data. Both stocks are short lived, poorly conditioned and have smolts whose fork lengths range between 19 and 26cm. Draft net fishing for these trout is conducted with relatively large meshed nets (4.45cm knot to knot). In the Feale highest catches are made in June and July and fish aged two sea summers constitute the majority of captures. A draft net mesh size smaller than the ordinary statutory minimum is required to retain large numbers of post-smoIt. A bunt mesh of 2.5cm knot to knot is effective in doing so.

The genus Alaria presently includes 12 species, 11 of which are located in the cold temperate North Pacific and only one is found in the North Atlantic (Widdowson, 1971). The North Atlantic species Alaria esculenta has two northern forms, A. esculenta forma grandifolia and forma pylaii (Lüning, 1990). The study presented here will concentrate on the genetic fingerprinting of Alaria esculenta, the most common North Atlantic species, and hybridisation of members of the Laminariaceae.