Genetic Variation A H F · Genetic Variation - Allelic diversity, A - Genetic consequences of...
Transcript of Genetic Variation A H F · Genetic Variation - Allelic diversity, A - Genetic consequences of...
Match/mismatch between biological and management units
Two types of spatial units
BIOLOGY MANAGEMENT Populations Stocks
The historical demarcation of the ICES distribution areas is a measure of convenience. It implies gross simplifications and assumptions on the biology of the fish. The spatial organisation of the true population structure, connectivity and life-history traits are not taken into account in the ICES areas. In addition, the associated overexploitation leads to loss of genetic diversity and potential to adapt. Key Questions: 1. What levels of genetic differentiation between populations justify
treatment as stocks that are managed separately? 2. How are these populations interrelated?
Genetics to unravel population processes
Connectivity of turbot and brill populations in European waters as a basis
for sustainable management
Sara Vandamme1,2, Kelle Moreau1, Gregory Maes2, Daan Delbare1, Stefan Hoffman1 and Filip Volckaert²
1Institute for Agricultural and Fisheries Research, Animal Sciences – Fisheries, Ankerstraat 1, 8400 Oostende, Belgium
² Katholieke Universiteit Leuven, Laboratory of Animal Diversity and Systematics, Ch. Deberiotstraat 32, 3000 Leuven, Belgium
Similarities in biology, fishery and current management
Habitat: sandy and stony bottoms down to 70 m, both salt and brackish waters Juvenile diet: benthivorous; adult diet: mainly piscivorous Spawning: April - August, pelagic eggs
By-catch species in fisheries targeting demersal fish (sole, plaice, dab, cod, …) Fishing methods: bottom trawls (beam and otter), gillnets, trammel nets, long lines High commercial value
No analytical assessment, only advice in Baltic based on historical trends EC requests analytical advice for all areas
Measure Biological info Application
Genetic Variation - Allelic diversity, A - Genetic consequences of demographic - Biodiversity conservation
- Heterozygosity, H processes: population fluctuations, - Genetic effect of MPAs
- Inbreeding, FIS reductions & bottlenecks - Genetic imprinting of fishing
Abundance - Effective population size, Ne - Population dynamics - Stock assessment & management
- Reproductive succes - Recruitement prediction
Structure and - Spatial genetic differentiation - Population structure - Management units definition
connectivity FST, RST, GST, D - Gene and migration flow - Delineation of MPAs
- Temporal genetic divergence - Mixed fisheries assessment
FST-Temporal
ABOVE Distribution and density of turbot in Europe
(fishbase.org). Brill has a similar distribution with much
lower densities in the Baltic and Black Seas.
Turbot Psetta maxima (© Luc Viatour)
Institute for Agricultural and Fisheries Research, Animal Sciences – Fisheries
Corresponding author: [email protected], +32(0)59/569896
other
COD
PLE
SOL SRX
INV TUR BLL
Landing-shares Belgian vessels 2000-2008 (tons)
Value-percentages Belgian landings 2000-2008
OTX
COD
PLE
SOL SRX
INV TUR
BLL
COD
PLE
SOL SRX
INV
BLL
TUR
RIGHT Relative importance of turbot and brill in A) Belgian
landings (all harbours) and B) Total Value of these
landings, summed over the period 2000-2008. Note that
both species show a significantly larger share in the value,
illustrating their high commercial values.
OTX
Landings
Value
COD = Cod Gadus morhua PLE = Plaice Pleuronectes platessa
SOL = Sole Solea solea SRX = Skates and Rays (Rajidae)
TUR = Turbot Psetta maxima BLL = Brill Scophthalmus rhombus
INV = invertebrates (crustaceans, shellfish and squid)
OTX = all other fish
Areas for stock
assessments defined by the
International Council for the
Exploration of the Sea
(ICES; www.ices.dk)
Belgian Beam trawler (© Kelle Moreau)
Future work: Delineation of biological populations based on genetics Characterisation and quantification of connectivity between populations Development of an appropriate assessment method taking these results into account