Browsing Irish Fisheries Bulletin by Author "Lordan, C."
Gutted to round-weight conversion factors for anglerfish (Lophius poscatorius and Lophius budegassa)Lordan, C.; Gerritsen, H.D. (Marine Institute, 2006)In response to a request from the Department of Communications Marine and Natural Resources and fishing industry, the conversion factors used to estimate round or live weights from gutted anglerfish were re-examined. A number of data sources was available from survey data, port sampling and observer trips. In some cases, the liver is left in place when the fish are gutted. For these landings a separate conversion factor is necessary. The conversion factors were found to be independent of fish size, however, some significant differences between the data sources were found. Significant differences between the conversion factors of the two species of anglerfish (Lophius piscatorius and L. budegassa) were also found. As commercial landings of anglerfish are not usually speciated, a generic conversion factor was estimated for Lophius spp. by combining the data for both species after weighting by the estimated proportions of the two species in the Irish landings. The resultant conversion factor for fully gutted fish is 1.23 and 1.17 when the liver is left in place; both estimates are lower than the current Irish factor of 1.28.
Irish fisheries-science research partnership trawl survey of the Porcupine Bank Nephrops Grounds July 2010Stokes, D.; Lordan, C. (Marine Institute, 2011)The Nephrops fishery on the Porcupine Bank takes place on a large area, approximately 7000km2, of complex muddy habitat between depths of 300 to 470m. Irish effort has been increasing and Ireland is now responsible for the majority of the landings. The scientific advice has indicated that the stock has declined and fishing mortality should be reduced to the lowest possible level. This Irish Fisheries Science Research Partnership (IFSRP) survey was developed in 2010 to address the pressing need for data from the closed area established by the EC between 1st May to 31st July 2010. 46 hauls were carried out and the results indicate high CPUE for the survey relative to recent observations for the fleet. Strong patterns in size and sex ratio were observed spatially. The male biased sex ratio and size-at-maturity are similar to historical observation. The size distributions of the catches are very different to the Spanish survey in the area which took place two months later. The utility of the survey for monitoring the stock is discussed.