• Using a multivariate approach to define Irish metiers in the Irish Sea

      Davie, S.; Lordan, C. (Marine Institute, 2009)
      There is an increasing need to take into account a “mixed fisheries” approach in management, assessment and sampling of fish stocks. To do this effectively it is necessary for groups of fishing trips with homogeneous fishing patterns or tactics to be defined into métiers. Presented here is the result of an Irish case study analysis in applying multivariate statistics to declared logbook landings to define Irish fleet métiers operating in the Irish Sea. Established multivariate statistical procedures, a combination of factorial and cluster analysis, were applied to five variables; landing profile, vessel length category, gear, mesh size range and month. The investigation has shown this methodology to be a suitable tool in identifying métiers without prior assumptions and enabled data to be described from a multivariate statistical perspective providing useful and informative results. In total twenty-two métiers were identified and defined from 2003 landings data, and a further 5 groups were formed to include trips which could not be assigned to a métier. Definitions were applied to 2003-2005 landings and effort data to examine their dynamics and stability. The dominant métier (in terms of effort and trips) contained high proportions of landed Nephrops taken by bottom otter trawlers using 70-89mm meshes. The effort in this métier was fairly stable over time. The greatest increases in effort and trip allocation occurred within métiers employing pots and traps for crustacean species. A small number of minor métiers (in terms of landings and effort) became obsolete over the three years examined. The effects of recent management measures are likely to have contributed to declines in the numbers of trips and effort in some métiers. For example, days-at-sea, limited mobile gears such as bottom otter trawls and beam trawls with ≥100mm mesh, have declined. Such changes within métiers over recent years have contributed to a deeper understanding of fleet dynamics in the Irish Sea. This analysis has identified and highlighted a segment of polyvalent Irish fishing vessels, which move between several métiers within a year. The definition of métiers can be used to enhance the Irish sampling programme in the Irish Sea by developing a finer scale, métier based, stratification of sampling. This in turn enables increased precision and robustness of national assessment data thus improving assessments and management advice. Defining métiers will prove advantageous in developing mixed fisheries assessments and advice.
    • Using Hydroacoustics to Describe Pelagic Fish Distribution in the Penobscot Estuary, Maine

      O’Malley, Michael B.; Saunders, Rory; Stevens, Justin R.; Jech, J. Michael; Sheehan, Timothy F. (Taylor & Francis, 2017)
      Temperate estuaries are inherently variable and productive ecosystems that provide nursery habitat, migration pathways, and forage areas for diadromous, estuarine, and marine fish. We used multifrequency scientific echo sounders (SIMRAD EK60 split‐beam, 38 and 120 kHz) to describe the distribution of pelagic fish in the Penobscot River estuary, Maine, in 2012 and 2013. Differences in responses between frequencies were used to distinguish fish from other biota. Acoustic area backscatter from echo integration (sA [m2/nautical mile2], a common measure proportional to fish density) and target strength (TS; dB re 1 m2, an acoustic measure of fish size) distributions varied with season and salinity. Overall, the sA and TS distributions were similar in both years, with detectable spatial and temporal patterns. The highest value of sA occurred in July of both years, when dense schools of fish were detected in higher‐salinity areas of the lower estuary. The middle estuary had high sA values in April both years, particularly in the vicinity of the seawater–freshwater interface. The mixing area in the middle estuary stratum appears to be important fish habitat; we found fish in this area throughout the year. Fish of variable TS were using this mixing zone throughout the survey period. In full freshwater, upstream from the salinity mixing area, sA was generally low. The majority (~77%) of discrete fish detected had TS values less than −42 dB. The TS distributions varied seasonally, with the highest TS measurements occurring more frequently in April and May and the lowest ones occurring most frequently in July and August. This study demonstrates the efficacy of using a mobile hydroacoustic survey to assess pelagic fish distribution in a complex estuary and may provide a template for long‐term monitoring in dynamic estuarine ecosystems.
    • Utilising caging techniques to investigate metal assimilation in Nucella lapillus, Mytilus edulis and Crassostrea gigas at three Irish coastal locations

      Giltrap, M.; Macken, A.; Davoren, M.; McGovern, E.; Foley, B.; Larsen, M.; White, J.; McHugh, B. (Elsevier, 2013)
      Pollution by metals has been of increasing concern for a number of decades but at present, the mechanism of metal accumulation in sentinel species is not fully understood and further studies are required for environmental risk assessment of metals in aquatic environments. The use of caging techniques has proven to be useful for assessment of water quality in coastal and estuarine environments. This study investigates the application of caging techniques for monitoring uptake of 20 elements [Li, Na, Mg, Al, P, K, Ca, V, Cr, Mn, Fe, Ni, Co, Cu, As, Sb, Pb, Hg, Cd and Zn] in three marine species namely Nucella lapillus, Mytilus edulis and Crassostrea gigas. Stable isotopes were used to determine predatory effects and also used for modelling metal uptake in test species and to track nutrient assimilation. Metal levels were monitored at three different coastal locations, namely Dublin Bay, Dunmore East and Omey Island over 18 weeks. Significant differences in concentrations of Mn, Co and Zn between mussels and oysters were found. Correlations between cadmium levels in N. lapillus and δ13C and δ15N suggest dietary influences in Cd uptake. Levels of Zn were highest in C. gigas compared to the other two species and levels of Zn were most elevated at the Dunmore East site. Copper levels were more elevated in all test species at both Dublin Bay and Dunmore East. Mercury was raised in all species at Dunmore East compared to the other two sites. Biotic accumulation of metals in the test species demonstrates that caging techniques can provide a valid tool for biomonitoring in metal impacted areas.
    • Validation of Standard Weights and Raising Coefficients for Discard Estimation: Report of a Survey Aboard MFV Roisin Bairbre

      Smith, T.; Comerford, S.; Officer, R. (Marine Institute, 2007)
      This survey was carried out to verify the Marine Institute's discard sampling protocol and the standard weights and conversion factors used when calculating discard rates. The MFV Roisin Bairbre was chartered to fish as normal on the Aran Prawn Grounds using twin rig prawn gear. The entire bulk catch was weighed, as well as the entire retained catch, thereby getting an accurate rate of discarding for this trip, as well as accurate individual basket weights. Retained catch was also weighed by species prior to and after gutting, to check the raising factors used when changing gutted landings back to round. This survey showed that the rate of discarding for this trip was 62% of the total bulk catch. There was no significant difference between the measured bulk catch weighed and the estimated bulk catch derived from using the standard weights. This validates the standard weights used. There was no significant differences between the observed conversion factors (from gutted to whole weight) and those currently used routinely in weight conversions. A standard weight for big baskets of bulk catch on a fish directed trip of 34.5 kg, and 28kg for a Nephrops directed trip were achieved.
    • Value of fish and shellfish landings into leading Irish ports 1962-1971

      Gibson, F A (Department of Agriculture and Fisheries (Fisheries Division), 1972)
      Landings of seafish are recorded under three broad headings, namely, demersal fish, pelagic fish and shellfish. The term demersal is applied to fish which live the greater part of their lives at or relatively near the sea bed. Demersal fish include roundfish such as whiting, cod, haddock, pollock and hake; flatfish such as plaice, sole, dabs, flounder, and also commercially valuable shark type fish such as skate and ray. The term pelagic is applied to fish which live the greater part of their lives in the upper layers of water and includes herrings, sprats, pilchards and mackerel. Shellfish include crawfish, lobsters, Nephrops (Dublin Bay prawns), crabs, shrimps and prawns all of which are known collectively as cruatacea; and escallops, mussels, oysters, periwinkles and various clams, which are known collectively as molluscs. The annual statistics published by the Fisheries Division of the Department of Agriculture and Fisheries give landings (by value) of approximately the leading 36 ports around the Irish coast.
    • Variability in the assignment of maturity stages of plaice (Pleuronectes platessa L.) and whiting (Merlangius merlangus L.) using macroscopic maturity criteria

      McGrath, D; Gerritsen, H.D. (Elsevier, 2006)
      This study investigates if a macroscopic scale can be applied consistently, by examining the variablity between and within ten people who repeatedly assessed the sex and maturity stages of 80 plaice (Pleuronectes platessa L.) and 79 whiting (Merlangius merlangus L.) gonads. In most cases, agreement within assessors was not significantly higher than agreement between assessors, suggesting that variability was random and not due to differences in interpretation. This finding was supported by the fact that a significant bias was only found for one assessor. Some maturity stages were assigned quite consistently, while other stages were not defined objectively enough to be assigned reliably, even when fish were assessed repeatedly by the same person. For both species, well-defined maturity scales with fewer stages would be prefereable over scales that distinguish a larger number of maturity stages. As maturity staging will always contain a form of subjective judgement, it should be subject to continuous quality control measures.
    • Varying disease-mediated selection at different life-history stages of Atlantic salmon in fresh water

      DeEyto, Elvira; McGinnity, Philip; Huisman, Jisca; Coughlan, Jamie; Consuegra, Sofia; Farrell, Killian; O'Toole, Ciar; Tufto, Jarle; Megens, Hendrik-Jan; Jordan, William; et al. (Blackwell Publisher, 2011)
      Laboratory studies on associations between disease resistance and susceptibility and major histocompatibility (MH) genes in Atlantic salmon Salmo salar have shown the importance of immunogenetics in understanding the capacity of populations to fight specific diseases. However, the occurrence and virulence of pathogens may vary spatially and temporally in the wild, making it more complicated to predict the overall effect that MH genes exert on fitness of natural populations and over several life-history stages. Here we show that MH variability is a significant determinant of salmon survival in fresh water, by comparing observed and expected genotype frequencies at MH and control microsatellite loci at parr and migrant stages in the wild. We found that additive allelic effects at immunogenetic loci were more likely to determine survival than dominance deviation, and that selection on certain MH alleles varied with life stage, possibly owing to varying pathogen prevalence and/or virulence over time. Our results highlight the importance of preserving genetic diversity (particularly at MH loci) in wild populations, so that they have the best chance of adapting to new and increased disease challenges as a result of projected climate warming and increasing aquaculture.
    • Veterinary treatments and other substances used in finfish aquaculture in Ireland

      Marine Institute (Marine Institute, 2007)
      Over recent years the finfish aquaculture sector has contracted in Ireland. The bulk of this sector is accounted for by marine salmon production. A number of substances are used in finfish farming that may give rise to discharges to the aquatic environment.
    • Vibriosis

      Marine Institute (Marine Institute, 2011)
      This leaflet gives information on vibriosis. This disease is a systemic bacterial infection caused by a gram negative, motile, rod shaped bacteria of the family Vibrionaceae.
    • Viral gametocytic hypertrophy of the Pacific oyster Crassostrea gigas in Ireland

      Cheslett, D.; McKiernan, F; Hickey, C; Collins, E (Inter Research, 2009)
      Viral gametocytic hypertrophy (VGH) was detected during an investigation of mortalities in Pacific oysters Crassostrea gigas from 2 separate Irish production sites. The basophilic inclusions were observed in the gonad tissue of oysters sampled in August and October 2007. The oysters involved did not show any macroscopic disease signs. Transmission electron microscopy demonstrated the presence of viral particles in these intranuclear inclusions. The particles were small, non-enveloped, icosahedral and approximately 50 nm in diameter and thus had characteristics similar to the Papillomaviridae and Polyomaviridae families. No host defence reaction was observed. The viral particles described here appear to be similar to those described in C. virginica from the USA and Canada and to those described in C. gigas from Korea and France.
    • Viral Haemorrhagic Septicaemia

      Marine Institute (Marine Institute, 2011)
      This leaflet gives information on viral haemorrhagic septicaemia (VHS). VHS is caused by a single stranded RNA virus of the family Rhabdoviridae, genus Novirhabdoviridae. VHS is listed as a non-exotic disease under EU Directive 2006/88/EC, and is notifiable in Ireland, according to S.I. No. 261 of 2008.
    • Visual Arts 5th and 6th Class. Ocean Literacy Principles and Concepts Art Project: Our Ocean – Our Future

      Marine Institute (Marine Institute, 2016)
      The objective of the Ocean literacy principles and concepts art project is for students to produce drawings based on their understanding of our ocean, using marine themes based on the seven ocean literacy principles and fundamental concepts for inspiration. The drawings may be further developed into paintings and other visual art mediums. The project should incorporate an art exhibition, and may include printing of postcards and bags.
    • Visual arts 5th and 6th class: Build your own unknown film set

      Marine Institute (Marine Institute, 2018)
      The lesson enables students to imagine, design and construct their own film set using recycled materials and papier-mache that is based on the Moytirra hydrothermal vent field. The students will experience working in groups and through a creative process develop skills intrinsic to working scientifically.
    • Visual arts 5th and 6th class: Light and shadow underwater scene

      Marine Institute (Marine Institute, 2018)
      The lesson enables students to differentiate between transparent, translucent and opaque materials and their different properties against light. Through a process of experimentation and creative play, students will create an underwater shadow scene.
    • Visual arts 5th and 6th class: Print your own hydrothermal vent field

      Marine Institute (Marine Institute, 2018)
      The lesson enables students to respond to scientific footage about hydrothermal vents and visually interpret their findings through a two-part printmaking process. The students will experiment with colour, line, shape and mark-making techniques to compose a print.
    • Visual Arts: 1st and 2nd Class - Constructing a marine themed structure – Lighthouse (Irish and English Version)

      Marine Institute (Marine Institute, 2014)
      The aim of the lesson plan is for children to explore and experiment with the properties and characteristics of materials in making structures based on a marine theme such as Lighthouses. They will respond to the lighthouses created in the class by talking about his/her work, as well as the work of other children.
    • Visual Arts: 1st and 2nd Class - Observing and Creating Paintings of Rough and Calm Seas (Irish and English Version)

      Marine Institute (Marine Institute, 2014)
      : The aim of the lesson plan is for children to be enabled to mix primary colours and use newly created colours expressively to interpret contrast in the natural world of the sea and ocean.
    • Visual Arts: 3rd and 4th Class - Creating an Underwater World of the Ocean in Fabric and Fibre Collage (Irish and English Version)

      Marine Institute (Marine Institute., 2014)
      The aim of the lesson plan is for children to be enabled to explore and discover the possibilities of fabric and fibre as medium for imaginative expression, designing and make a collage based on the “Underwater World of the Ocean”. They will respond to the lighthouses created in the class by talking about his/her work, as well as the work of other children.
    • Visual Arts: 3rd and 4th Class - Drawing Still Life Scenes of items from the Seashore (Irish and English Version)

      Marine Institute (Marine Institute, 2014)
      The aim of the lesson plan is for children to create still life drawings of items from the seashore. The children will be enabled to respond to other artist’s works as well as completing their own drawings by experimenting with the marks, lines, shapes, textures, patterns and tones that can be made with different drawing instruments on a range of surfaces. The children will respond to the pictures created in the class by talking about his/her work, as well as the work of other children.
    • Visual Arts: 3rd to 6th class - Creating and Making a textured Shell Collage Picture

      Marine Institute (Marine Institute, 2015)
      The students will explore and experiment with the properties and characteristics of materials (shells, sand, stones etc) in making seashore textured collages. They will learn to use their imagination to make a textured seashore picture using shells and sand.