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In Other Words

May 19
Fisheries genetics

​Naiara Rodríguez-Ezpeleta of the Working Group on Application of Genetics in Fisheries and Mariculture (WGAGFM) and co-organizer of the EuroMarine Foresight Workshop on the Application on Population Genomics to Fisheries Management.”​

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'The genetic information stored in each of the cells of the individuals of each species can provide crucial information for understanding processes that cannot otherwise be studied or provide more cost-effective measurements than traditional methods. 

Species identification can be achieved using barcoding: the amplification of a short variable DNA fragment that, compared against a reference database, is used for taxonomic assignment. This technique is particularly relevant for morphologically similar species (e.g. black and white anglerfish), early developmental stages (eggs and larvae), semi-digested specimens (e.g. stomach contents) or animal pieces (e.g. shark fins).

Stock delineation can be achieved using population genetics, which relies on the analysis of genetic markers that are variable within a single species (microsatellites and SNPs are the most widely used ones). If a large number of these markers are conserved within a group of individuals, it may indicate reproductive isolation​, either due to distance (isolation by distance) or reproductive behavior (homing) for example.

Origin assignment can be achieved by typing on the individual to be assigned a subset of informative markers from the ones identified during the stock delineating process. This is particularly relevant for identifying the origin of a landed catch or to assign individuals to a stock in the case of mixed-stock fisheries (e.g. salmon caught at sea can be assigned back to its river of origin).

Adaptive genetic changes can be identified by studying those markers that present the same variants within individuals that inhabit similar conditions and that are not the result of isolation by distance. (e.g. same genetic markers are responsible for the adaptation to warm temperatures in cod inhabiting the east and west Atlantic).

There are many other fishery assessment questions to which genetics can provide relevant information. Recently, two methods that promise to revolutionize the field are 1) the close-kin mark recapture method, which potentially allows estimating fisheries independent abundances from genetic data and 2) the analysis environmental DNA (eDNA), which is DNA released into the environment in the form of skin, blood, mucus, for example, which can provide information about the species inhabiting a given environment without needing to see or sample them.'


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