title: Growth in Nephrops norvegicus from a tag-recapture experiment.
abstract: Nephrops norvegicus is a commercially valuable fishery in the EU but management of stocks is challenging due to difficulties in aging individuals and calculating growth and biomass production. Growth of N. norvegicus was estimated by releasing 1177 tagged individuals in western Ireland in Summer 2013 and recapturing these in 2014 (n = 207, an average of 344 days later) and 2015 (n = 38, 654-665 days later). Moulting occurred twice per year in approximately half of the males and only once in females. Mean growth increments after approximately one year were 5.1 mm Carapace Length (CL) in males and 1.4 mm CL in females. After two years, males had grown by 12.0 mm CL and females by 4.6 mm CL, on average, across size classes. Low variation in growth increments was seen across female size classes, but significantly lower growth was observed in larger males, meeting an important assumption of the Von Bertalanffy Growth Function. Asymptotic carapace lengths were 70.8 mm (males) and 55.2 mm (females) with respective growth constants (k) of 0.161 yr-1and 0.077 yr-1. The results suggest that this is a very productive fishery and that survivability of returns from creel fishing is high.
authors.affiliation: Ryan Institute, School of Natural Sciences, National University of Ireland Galway, Ireland.
authors.forename: Paula S
authors.initials: PS
authors.lastname: Haynes
authors.affiliation: Ryan Institute, School of Natural Sciences, National University of Ireland Galway, Ireland.
authors.forename: Patricia
authors.initials: P
authors.lastname: Browne
authors.affiliation: Ryan Institute, School of Natural Sciences, National University of Ireland Galway, Ireland.
authors.forename: Liam
authors.initials: L
authors.lastname: Fullbrook
authors.affiliation: Marine and Freshwater Research Centre, Department of Life Sciences, Galway-Mayo Institute of Technology, Galway, Ireland.
authors.forename: Conor T
authors.initials: CT
authors.lastname: Graham
authors.affiliation: Ryan Institute, School of Natural Sciences, National University of Ireland Galway, Ireland.
authors.forename: Lee
authors.initials: L
authors.lastname: Hancox
authors.affiliation: Ryan Institute, School of Natural Sciences, National University of Ireland Galway, Ireland.
authors.forename: Mark P
authors.initials: MP
authors.lastname: Johnson
authors.affiliation: Marine Institute, Plymouth University, Plymouth, United Kingdom.
authors.forename: Valentina
authors.initials: V
authors.lastname: Lauria
authors.affiliation: Ryan Institute, School of Natural Sciences, National University of Ireland Galway, Ireland.
authors.forename: Anne Marie
authors.initials: AM
authors.lastname: Power
mesh_terms: D060105:Animal Shells / Q000254:growth & development; D000818:Animals; D017756:Aquaculture; D005260:Female; D007494:Ireland; D008297:Male; D018978:Molting; D008121:Nephropidae / Q000254:growth & development*; D013194:Staining and Labeling