Showing papers in "Biology and Environment-proceedings of The Royal Irish Academy in 2004"
TL;DR: Multivariate morphometric and meristic analyses of Irish Arctic char Salvelinus alpinus from Lough Eske, Co.
Abstract: Multivariate morphometric and meristic analyses of Irish Arctic char Salvelinus alpinus (L.) from Lough Eske, Co. Donegal, and Lough Mask, Co. Mayo, are presented. The analysis illustrated the monomorphic character of the two populations despite differences in growth and size between the ‘stunted’, slower-growing Lough Eske fish and the ‘normal’, faster-growing Lough Mask fish. The results are discussed in the context of other systems where sympatric morphs have been described. Differences in body size and growth rate appear to reflect the trophic status and the productivity of the two lakes. The results confirm earlier findings, which were based on dietary analysis and analysis of metazoan parasites of both Irish populations of Arctic char.
24 citations
TL;DR: The perceived threats to the twaite, Killarney and allis shad in Ireland, where they have been categorised as ‘vulnerable’ to extinction (twaite shad) and ‘endangered’ (Killarneys and alli shad), are listed and discussed.
Abstract: Anadromous twaite shad (Alosa fallax Lacepede) and allis shad (Alosa alosa L.) occur in Irish coastal waters, although only twaite shad has been confirmed to reproduce in Ireland. A landlocked subspecies of the twaite shad, known as the Killarney shad (Alosa fallax killarnensis), occurs in Lough Leane in south-western Ireland. Relatively little scientific research has been undertaken on the marine phases of these species in Ireland except for occasional reports of coastal bycatch. The growth, diet and parasite assemblages of twaite and allis shad sampled from Waterford Estuary and the upper tidal reaches of the River Barrow have been investigated since 1995. Similarly, aspects of the Killarney shad have been investigated since 1986. The number of gill rakers or general body size easily separates these subspecies of shad. The perceived threats to the twaite, Killarney and allis shad in Ireland, where they have been categorised as ‘vulnerable’ to extinction (twaite shad) and ‘endangered’ (Killarney and allis shad), are listed and discussed.
14 citations
TL;DR: It is argued that the genetic diversity within species such as brown trout needs to be recognised by state agencies and fishery managers and that separate species recognition is appropriate in some instances.
Abstract: Ireland's freshwater fish fauna, which is less diverse than that of the UK or mainland Europe, was historically dominated by salmonids. Subsequent changes to the species community in many waters has occurred due to a combination of human influences, including non-indigenous fish introductions, water pollution and habitat alterations. However, intact postglacial fish communities still remain in many parts of the country, and maintaining the biodiversity of these communities is of particular importance. It is argued that the genetic diversity within species such as brown trout needs to be recognised by state agencies and fishery managers and that separate species recognition is appropriate in some instances. The paper discusses the development of freshwater fish conservation in the Irish Republic today and deal specifically with the main state agencies entrusted with their conservation, the Fisheries Boards. The paper reviews the more significant pieces of legislation at the disposal of the Fisheries Boards and other environmental authorities and highlight areas that require further attention. Irish planning legislation and some of the problems currently being encountered by Fisheries Boards in relation to the planning process are also examined.
9 citations
TL;DR: Water-quality monitoring data collected monthly from 1993 to 1999 and information on phytoplankton available since 1951 show that salmon culture can be conducted in a freshwater lake for over thirteen years without polluting either the water or lake bed.
Abstract: Evaluation of the long-term cumulative impacts of fish farming requires long-term data sets. In this study, we analysed water-quality monitoring data collected monthly from 1993 to 1999 and information on phytoplankton available since 1951. Seventeen parameters were measured in water at the farm and control sites: namely oxygen, nitrite, nitrate, ammonia, total phosphorus (TP), soluble reactive phosphate, chlorophyll a, suspended solids, pH, biochemical oxygen demand, chemical oxygen demand, alkalinity, silicate, total nitrogen (TN), conductivity, colour and temperature. Lake bed sediments and water at the cages were analysed for TP, TN and organic carbon in 1988, 1990 and 1998. The phytoplankton indicate that there have been no changes in the oligotrophic status of the lake since 1951. There were no trends in water quality over the past fifteen years. Except for ammonia, no other significant differences in water parameters between farm and control sites were detected. Chemotherapeutants were not detected. Several parameters were more variable in near-shore water samples than in fish cages and open-water control sites. There was seasonal variation in water parameters and a thermocline in summer. At the fish cages, ammonia was elevated above and oxygen depleted below the thermocline. These levels were not a risk to fish health and were not of environmental concern, nor were they close to permitted levels. In sediments there were no significant correlations between TP and TN and none between lake depth or distance from the cages. Overall, this study shows that salmon culture can be conducted in a freshwater lake for over thirteen years without polluting either the water or lake bed.
3 citations