Marine Institute Open Access Repository

Welcome to the Marine Institute Open Access Repository

The Marine Institute Open Access Repository facilitates full text access to the publications of the Marine Institute in accordance with copyright permissions. The aim of the Repository is to collect, preserve and provide open access to the publications of the Marine Institute, including the research publications supported by National and European funded marine research programmes.



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  • Catch and bycatch in the tangle net fishery for crayfish (Palinurus elephas) off the south west coast of Ireland

    Tully, Oliver; Palma-Pedraza, S. (Marine Institute, 2022)
    Crayfish or spiny lobster is fished off the south west coast of Ireland. There are also smaller fisheries on the west and north west coasts. Although historically, prior to the 1970s, the main fishing gear used in the fishery was top entrance traps crayfish are now targeted with large mesh tangle nets. The selectivity of these nets is poor and there is known to be a by-catch of finfish, skates and rays and protected species such as grey seal. The fishery usually occurs from mid-March to December. The species composition and size distribution of the catch and by-catch was surveyed over a 4 year period from 2017-2020 from Dingle Bay north to the Shannon Estuary. Additional data south of this area was obtained in 2020. A crayfish tagging programme was undertaken in 2017 and 2018. Between 2 and 6 vessels participated in the programme depending on year Most of the data was reported directly by Skippers and crew who were contracted to supply data. Scientific observers covered a proportion of trips in 2017 and 2019. A total of 1500 nmiles of tangle net hauls were surveyed across 6 vessels. A total of 11792 crayfish and 899 lobsters were measured, 1234 crayfish were tagged and released and 45 recaptures were reported. Spider crab, brown crab and crayfish were the numerically dominant species in the catch. Lobster, pollack, thornback ray, spurdog, monkfish and turbot were caught regularly in low numbers. There was no cetacean by-catch. A total of 200 grey seals were caught over the 4 year period by the vessels participating in the survey. Endangered and critically endangered species, including flapper skate, common skate, angel shark and white skate, were caught in very low numbers. The finfish catch is mainly lost to scavengers or seal depredation before nets are retrieved and because of long soak times which averaged 8 days. This reduces the value of the catch. The average value of the live crustacean (crayfish, lobster, brown crab) catch was approximately €300 per mile of net hauled. Crayfish were tagged and released in 2017 and 2018 and recaptured during the period 2017-2020. Three crayfish tagged by IFREMER off Brittany in 2015 and 2016 were recaptured off the south west and west coast of Ireland in 2019. The northern most recapture was off Erris Head Co. Mayo. The tagging data shows that most crayfish were recaptured locally close to release points even in the years following tagging. It is still unclear if crayfish are resident or if they migrate in and out of the tagging area as the reporting rate of recaptures outside the tagging area is unknown. The by-catch of critically endangered species poses a high risk to the continued presence of these species in Irish waters and indeed in European waters given that the area is known to hold the last European remnant populations of species such as angel shark and white skate. Grey seal by-catch was related to the distance between the fishing event and the nearest seal colony haul out at the Blasket Islands. Sixty % of seals were caught within 10km of the haul out. The probability of capture in a single net haul declined from 30-35% within 10km to 9-14% at distances of 10-30km to 4% at distances of 40-60km and zero at distances greater than 60km (data for 39 hauls >60km). The high by-catch of grey seal is a significant risk to the Blasket Island seal colony. It is unlikelythat the Blasket population can sustain this level of by-catch mortality without inward migration fromother colonies.
  • The Irish Maritime Transport Economist Volume 19

    Irish Maritime Development Office (Marine Institute, 2022)
  • The Biologically Sensitive Area: A review of the basis and effectiveness

    APEM (Marine Institute, 2021)
    The Biologically Sensitive Area (BSA) designation is a multiuse area of protection to the south and west of Ireland. The BSA was established within a political context based on three core ideas, namely: (1) to prevent overfishing, (2) protect hake stocks and (3) protect spawning and nursery areas found in this area. The area was established in 2003 to limit fishing within the area, and replaced the previous larger ‘Irish Box’ which had surrounded Ireland.
  • Ireland’s Ocean Economy, 2022

    Norton, Daniel; Hynes, Stephen; O'Leary, Jenny; O'Donoghue, Cathal; Tsakiridis, Andreas; Lanser, Marie-Christin (Marine Institute, 2022)
    This report provides an update on Ireland’s ocean economy across three main economic indicators: turnover, gross value added (GVA) and employment, and provides an analysis of trends over the last five years. The report also reviews demographic change in Ireland’s coastal economy, as well as highlighting developments in marine natural capital accounting. The economic trends are presented in the context of key drivers (e.g. policy, legislative, geo-political) that are directly or indirectly impacting on the performance of the ocean economy industries currently and possibly impacting into the future. This report is the sixth in the ocean economy series2. The methodology used in compiling this report builds on previous reports allowing for a complete and comparable representation of Ireland’s ocean economy across all industries. The reference year for the data is primarily 2020 (based on best available data), with estimates based on economic projections of Ireland’s ocean economy up to 2021 also provided. These estimates are based on a forecasting exercise that combines the latest published economic data from the CSO, BIM, government economic forecasts, information and data obtained from surveys with marine-related businesses, and insights from government departments and agencies.
  • Western European Shelf Pelagic Acoustic Survey (WESPAS) 14 June –24 July, 2022. FSS Survey Series: 2022/03

    O'Donnell, Ciaran; O’Malley, Michael B.; Mullins, Eugene; Power, John; judge, Justin; Croot, P. (Marine Institute, 2022)
    The WESPAS survey program is the consolidation of two existing survey programs carried out by FEAS, the Malin Shelf herring acoustic survey, and the boarfish acoustic survey. The Malin Shelf herring acoustic survey has been carried out annually since 2008 and reports on the annual abundance of summer feeding aggregations of herring to the west of Scotland and to the north and west of Ireland from 53°30’N to 58°30’N. The boarfish survey was conducted from 2011 using a chartered fishing vessel and reported the abundance of spawning aggregations of boarfish from 47°N to 57°N. In 2016 both surveys were combined into the WESPAS survey and have been carried out onboard the RV Celtic Explorer over a 42-day period, providing synoptic coverage of shelf waters from 47°30’N northwards to 58°30’N. Age stratified relative stock abundance estimates of boarfish, herring and horse mackerel within the survey area were calculated using acoustic data and biological data from trawl sampling. Stock estimates of boarfish and horse mackerel were submitted to the ICES assessment Working Group for Widely Distributed Stocks (WGWIDE) meeting in August 2022. Herring estimates are submitted to the Herring Assessment Working Group (HAWG) meeting in March every year. Survey performance will be reviewed at the ICES Planning Group meeting for International Pelagic Surveys (WGIPS) meeting in January 2023.

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