title: Reproductive biology of female Norway lobster, Nephrops norvegicus (Linnaeus, 1758) Leach, in Icelandic waters during the period 1960-2010: comparative overview of distribution areas in the Northeast Atlantic and the Mediterranean.
abstract: Maturity size, reproductive cycle, sex ratio and fecundity of female Nephrops were investigated at SW, S and SE Iceland for the period 1960-2010. Time series of biological parameters and fisheries data displayed significant relationships. In addition, female biological data from 20 areas in the Atlantic and Mediterranean were compared. Fifty percentage maturity estimates had an overall range of 23.9-34.4mm CL with some anomalies in the 2000s. The reproductive cycle in Iceland has been biennial during the whole study period from mid-1960s to 2010 with minor change in phase in the 2000s. Biennial moulting retards female growth more than annual spawning, and the length of incubation and hatch time of year show significant relationships with latitude and sea temperature. Variations in sex ratio were observed and relationships found between female sex ratio and CL, CPUE and stock biomass during 1961-2010, displaying apparent fishery-induced effects on sex ratio. Potential and realized fecundity estimates in Iceland are 35-50% of those reported from more southerly waters. Biennial spawning and low fecundity limit the number of progeny in Icelandic Nephrops and necessitate lower fishing mortality. Ambient temperature in Icelandic waters has risen by 1°C since the late 1990s, generating around 30 days shorter incubation time in the 2000s, but around 3°C rise is necessary for possible annual spawning.
authors: Marine Research Institute, Skúlagata 4, Reykjavík, Iceland. Electronic address: keli@hafro.is.
authors: Hrafnkell
authors: H
authors: Eiríksson
mesh_terms: D000818:Animals; D001267:Atlantic Ocean; D005260:Female; D007055:Iceland; D008522:Mediterranean Sea; D008121:Nephropidae / Q000502:physiology*; D012098:Reproduction / Q000502:physiology; D012621:Seasons; D013997:Time Factors
keywords: Biennial spawning; Fecundity; Geographical variations; Nephrops norvegicus; Sea temperature; Sex ratio; Size of maturity