Brief description
Determining the extent of dispersal in exploited marine fishes is essential for understanding their population dynamics and optimising management. The West Australian dhufish, Glaucosoma hebraicum, is a sought-after, large and long-lived reef-dwelling species, endemic to south-western Australia. We analysed 13 microsatellite loci to characterise the extent of gene flow, and conducted particle tracking simulations to model larval transport in this species. Genetic data demonstrated that some local recruitment was likely, but that on a broad scale gene flow between the management zones was extensive, and the entire fishery represents a single genetic stock. In contrast, hydrodynamic modelling predicted that the majority of dhufish larvae recruit from within the management zone where they are spawned, and that inter-annual variation in current velocities has little effect on the extent of larval transport. The existing management zones are likely to be largely independent in terms of both larval and adult recruitment.Lineage
Statement: *Sampling* Samples were obtained from recreational and/or commercial anglers between Kalbarri (21.51°S, 114.00°E) and Esperance (34.07°S, 121.99°E), in Western Australia between November 2007 and August 2008 (see thumbnail). Adipose fin clip samples (ca. 5mm x 25mm) were taken and stored in NaCl saturated DMSO. A total of 466 fish were sampled, and of these, ages of 392 fish (84.4%) were determined following validated methods using otolith growth zones (Hesp et al., 2002). The majority of sampling locations were obtained from fishers to the nearest 5 nautical miles (9.3 km), but some samples had more precise GPS coordinates recorded. *Lab and statistical analysis* DNA was extracted with a 96-well silica/guanidine thiocyanate method as described by Ivanova et al. (2006). Eluted DNA was diluted 1/3 for PCR analysis. Thirteen microsatellite DNA loci were amplified with PCR according to methods described in Burridge and England (2009). Products were analysed on an ABI 3700 fragment analyser, and alleles were allocated to bins by eye with Genemarker software (Softgenetics, PA, USA). The total dataset was checked for variability and departures from Hardy-Weinberg and gametic-phase equilibrium with the exact test based on the methods of Guo and Thompson (1992) and implemented in the program Genepop007 (Rousset, 2008). Further details are given in final report *Hydrodynamic modelling* We modelled the transport of larval fish with a Lagrangian particle tracking simulation nested within a global hydrodynamic model generated from the BlueLink Reanalysis (BRAN2; Schiller et al., 2008). This analysis was facilitated by the ConnIe2 computer program (updated from Condie et al., 2005). ConnIe2 enables estimation of the probability that any two regions are connected by modelled ocean circulation over a specified period of dispersal. It is based on offline particle tracking within a three-dimensional hydrodynamic model and incorporates information from wind fields, temperature, salinity, sea level and tides (see Condie et al., 2005, Condie & Andrewartha, 2008, Schiller et al., 2008). Particles were released at 24 approximately equally-spaced locations between Kalbarri and Albany and within a transect composed of three 10 x 10 km cells running perpendicular to the shore (see thumbnail).Modified: 21 07 2011
text: westlimit=112; southlimit=-35; eastlimit=117; northlimit=-22
Subjects
AGRICULTURAL AQUATIC SCIENCES |
AGRICULTURE |
ANIMALS/VERTEBRATES |
BIOLOGICAL CLASSIFICATION |
BIOSPHERE |
EARTH SCIENCE |
ECOLOGICAL DYNAMICS |
Fish |
Fisheries |
Glaucosoma hebraicum |
Larval Dispersal |
Microsatellite Marker |
OCEAN CIRCULATION |
Ocean Currents |
OCEANS |
Population Dynamics |
Particle Tracking Simulations |
SPECIES/POPULATION INTERACTIONS |
biota |
oceans |
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Other Information
global : 3c0553d9-d5ba-48e5-8766-f8d7cf39143a
Identifiers
- global : 8279116c-5e3f-401d-bd2b-61d9ff1294a9
