Carlsson, J,Shephard, S,Coughlan, J,Trueman, CN,Rogan, E,Cross, TF;

2011

January

Deep-Sea Research Part I-Oceanographic Research Papers

Fine-scale population structure in a deep-sea teleost (orange roughy, Hoplostethus atlanticus)

Published

()

Population structure Seafloor topography Microsatellite Otolith chemistry Orange roughy Hoplostethus atlanticus NEW-ZEALAND GENETIC DIVERSITY NORTHEAST ATLANTIC MICROSATELLITE DATA MITOCHONDRIAL-DNA COMPUTER-PROGRAM PORCUPINE BANK TASMAN SEA FISH WATER

58

627

636

Microsatellite and otolith chemistry variability were analysed to assess fine scale genetic structure in the deep-sea teleost orange roughy (Hoplostethus atlanticus). The Porcupine Bank located on the continental shelf west of Ireland, comprises a complex system of mounds and flat areas that are broken up by canyons. Orange roughy form spawning aggregations on mounds and flat areas, and were heavily fished until the resource was depleted. By analysing adults in spawning condition and juvenile orange roughy from six mounds and one flat area, shallow but significant genetic population structure was evident (F-ST=0.0031, D-est across loci=0.0306 and G-test). Most of the structure was accounted for by inclusion of a sample from the flats (six of ten significant pairwise F-ST estimates and G-tests, and five of the highest D-est estimates included the flat sample). While the flat sample contributed most to the genetic structure, there was still significant (albeit weaker) structure among mound samples. The observed structure was supported by otolith analyses. Fish caught as late juveniles in either the flat or mound areas showed consistent differences in chemistry at the otolith core throughout the initial 10 years of growth, which could indicate site fidelity. We hypothesise that seafloor topographic structures (mounds and flats) may provide discrete spawning areas for orange roughy and that the limited gene flow between these spawning areas is insufficient to counteract genetic drift. (C) 2011 Elsevier Ltd. All rights reserved.

DOI 10.1016/j.dsr.2011.03.009