Factors influencing the downstream transport of sediment in the Lough Feeagh catchment, Burrishoole, Co. Mayo, Ireland

Research laboratories in the Burrishoole catchment have been the focus of salmonid research since 1955. One aspect of the research has been to monitor the number of salmon and sea trout migrating to sea as smolts and returning to the catchment as adults. In the early 1990s it became clear that the smolt output from the catchment had declined over the previous two decades. At about the same time the presence of fine particles of peat silt in the hatchery became increasingly apparent and led to a higher incidence of mortality of young fry. These observations and management difficulties led to a study of silt transport in the surface waters of the catchment, which is described in this article. The authors describe geology, soils, climate and hydrology of Burrishoole before examining the sediment deposition in Lough Feeagh

CE24002 and CE24005

The 2024 Irish Anglerfish and Megrim Survey (IAMS) took place from 8th February to 3rd March in ICES (International Council Exploration of the Sea) Divisions 7.b-c and 7.j-k, and 12th to 21st April in ICES Division 6.a on-board the Research Vessel Celtic Explorer. The main objective of the survey was to obtain biomass and abundance indices for anglerfish (Lophius piscatorius and Lophius budegassa) and megrim (Lepidorhombus whiffiagonis and Lepidorhombus boscii) in ICES Division 6.a (south of 58°N) and Subarea 7 (west of 8°W). Secondary objectives were to collect data on the distribution, relative abundance and biology of other commercially exploited species. For the sixth year, additional sampling took place in deep water (up to 1,500m) in order to monitor the recovery of exploited deep-water species following the decline of the deep-water fisheries in Irish waters since early 2000s (Kelly and Gerritsen, 2022). This work was funded under Marine Biodiversity Schemes of the European Maritime and Fisheries Fund (EMFF) from 2019 to 2021 and European Maritime, Fisheries and Aquaculture Fund (EMFAF) since 2022. The IAMS survey is coordinated with the Scottish Anglerfish and Megrim Survey (SIAMISS) as part of ICES International Bottom Trawl Survey Working Group (IBTSWG) and uses the same gear and fishing practices

Length–weight relations for seven grenadier species (actinopterygii: gadiformes: macrouridae) to the west of ireland

Length-weight regressions for seven grenadier species: Coryphaenoides rupestris Gunnerus, 1765, Trachyrincus murrayi Gunther, 1887, Coelorinchus caelorhincus (Risso, 1810), Nezumia aequalis (Gunther, 1878), Coryphaenoides mediterraneus (Giglioli, 1893), Coelorinchus labiatus (Kohler, 1896), and Coryphaenoides guentheri (Vaillant, 1888) are calculated from data collected on a series of deepwater surveys conducted by the Irish Marine Institute from 2006 to 2009, on the continental slope to the west and northwest of Ireland and the northern slope of the Porcupine Bank. The regression calculated for roundnose grenadier, C. rupestris, is compared with other regressions calculated for the species from different areas of its north Atlantic range. The difficulties associated with measuring many grenadier species, due to the fragility of their tails, are discussed. A recommendation is made that pre-anal fin length should be accepted as the standard

Data from: Trophic interactions of fish communities at midwater depths enhance long-term carbon storage and benthic production on continental slopes

Biological transfer of nutrients and materials between linked ecosystems influences global carbon budgets and ecosystem structure and function. Identifying the organisms or functional groups that are responsible for nutrient transfer, and quantifying their influence on ecosystem structure and carbon capture is an essential step for informed management of ecosystems in physically distant, but ecologically linked areas. Here, we combine natural abundance stable isotope tracers and survey data to show that mid-water and bentho-pelagic-feeding demersal fishes play an important role in the ocean carbon cycle, bypassing the detrital particle flux and transferring carbon to deep long-term storage. Global peaks in biomass and diversity of fishes at mid-slope depths are explained by competitive release of the demersal fish predators of mid-water organisms, which in turn support benthic fish production. Over 50% of the biomass of the demersal fish community at depths between 500 and 1800 m is supported by biological rather than detrital nutrient flux processes, and we estimate that bentho-pelagic fishes from the UK&ndash;Irish continental slope capture and store a volume of carbon equivalent to over 1 million tonnes of CO2 every year.,Trueman 2014 Fish Isotope dataStable isotope data (d13C PDB and d15N air) from white muscle tissue of fishes caught by demersal trawl on the Rockall trough. Associated data are: Species name, feeding type (benthic or benthopelagic), capture (trawl) depth in meters and fish mass in grammes,</span

Trueman 2014 Fish Isotope data

Stable isotope data (d13C PDB and d15N air) from white muscle tissue of fishes caught by demersal trawl on the Rockall trough. Associated data are: Species name, feeding type (benthic or benthopelagic), capture (trawl) depth in meters and fish mass in gramme

Fitness reduction and potential extinction of wild populations of Atlantic salmon, Salmo salar, as a result of interactions with escaped farm salmon.

The high level of escapes from Atlantic salmon farms, up to two million fishes per year in the North Atlantic, has raised concern about the potential impact on wild populations. We report on a two-generation experiment examining the estimated lifetime successes, relative to wild natives, of farm, F(1) and F(2) hybrids and BC(1) backcrosses to wild and farm salmon. Offspring of farm and "hybrids" (i.e. all F(1), F(2) and BC(1) groups) showed reduced survival compared with wild salmon but grew faster as juveniles and displaced wild parr, which as a group were significantly smaller. Where suitable habitat for these emigrant parr is absent, this competition would result in reduced wild smolt production. In the experimental conditions, where emigrants survived downstream, the relative estimated lifetime success ranged from 2% (farm) to 89% (BC(1) wild) of that of wild salmon, indicating additive genetic variation for survival. Wild salmon primarily returned to fresh water after one sea winter (1SW) but farm and 'hybrids' produced proportionately more 2SW salmon. However, lower overall survival means that this would result in reduced recruitment despite increased 2SW fecundity. We thus demonstrate that interaction of farm with wild salmon results in lowered fitness, with repeated escapes causing cumulative fitness depression and potentially an extinction vortex in vulnerable populations