Fisheries research

Nephrops norvegicus

Sediment characteristics and local hydrodynamics and their influence on the population of Nephrops around Ireland

Many marine invertebrates exist as metapopulations comprised of disparate local populations whose persistence depends on rates of larval delivery and recruitment, and thus connectivity between populations. For commercially exploited species, predicting connectivity of the metapopulation would enable estimates of potential annual recruitment and help inform fisheries management decisions to ensure sustainable exploitation. The Norway lobster, Nephrops norvegicus, is the second most valuable commercial species landed from Irish waters. Its distribution depends on the presence of suitable sediment and larval supply. The aim of this study was to improve understanding of Nephrops metapopulation connectivity in waters around Ireland and between disparate fished populations in the wider northeast Atlantic. We employed INFOMAR data, combined with hydrodynamic and larval transport models to describe spatial and temporal changes in oceanographic conditions and quantitatively predict the degree of connectivity between populations. The simulations suggested that there are three isolated populations (Porcupine Bank, Southwest Slope and Irish Sea), whereas a network of populations along the south coast of Ireland are likely interconnected and act as a metapopulation. These results can be used to inform management decisions for the interconnected stocks and contribute to a more sustainable fishery.


A representation of larval dispersal over time from Nephrops fishing areas in the Celtic Sea and the Irish Sea. Reading each panel from top to bottom indicates the general pattern of dis-persal from each ground over time. Arrow lengths correspond to respective dispersal distance per week. Red dots indicate locations of hatchings on the 1st of each month.