Chilean mussel larvae, Mytilus chilensis, seen with a microscope. (Photo: Cetmis)
Mussel seed recruitment boosted with immunofluorescence
Thursday, December 07, 2017, 21:50 (GMT + 9)
By means of laboratory techniques, it is now possible to know the abundance of Chilean mussel (Mytilus chilensis) larvae in the natural environment, an advance that will facilitate productive decision-making, such as the installation of collectors.
Chile is the second global mussel producer, after China, and the first exporter of this resource, in an industry made up of seed collectors (juveniles), feeders and processors.
The productive capacity of this sector is subject to obtaining seeds from the natural environment, which is achieved by fixing larvae of this resource on substrates installed by those who collect them. This process is part of a chain whose first link should be to identify and quantify the abundance of larvae present in the environment.
Until a few years ago, mussel larvae quantification was performed almost exclusively by microscopic observation done by an expert person, able to distinguish the different larval species of bivalves present in the plankton. This methodology limits the identification and presents a degree of uncertainty, since in nature there is a great variety of species and sizes of larvae coincide in the same period of time, which makes an accurate characterization extremely difficult.
In view of this situation, Chinquihue Foundation recognized the availability of a technique based on immunodetection for the safe and rapid quantification of Chilean mussel larvae at the University of Vigo (Spain). This technique allows to distinguish with certainty these larvae from those of other bivalves, especially Chilean ribbed mussel (Aulacomya ater) and chorus mussel (Choromytilus chorus), which are undesired species for the mussel industry.
The immunodetection technique considers taking samples in the field through a plankton network and transferring them to the laboratory, where a cleaning process begins through centrifugation with a sugar gradient, to separate the bivalve larvae from microalgae and other planters, such as small crustaceans.
After this cleaning process, bivalve larvae are incubated with two antibodies, the first one "adheres" only to larvae of the Mytilus genus, while the second antibody has a fluorescent yellow fluorochrome that binds to the first one. In this way, if there are Chilean mussel larvae in the sample, they will be "dyed" with a phosphorescent yellow colour, especially at the edge of the mantle, and thus they can be identified and differentiated from larvae of other bivalve species.
Currently, through the Technological Extension Centre for Sustainable Mussel Farming (CETMIS), performed by Chinquihue Foundation and supported by CORFO, larval abundance information is being released in different areas of Los Lagos Region, quantified by the immunodetection technique (http://www.cetmis.cl/home/servicios/informe-larvario/). In this way, information that allows mussel farmers to make productive decisions in an informed manner is made freely available, for example for the installation of seed collectors at the most appropriate time, or to buy collectors from areas where there was a great abundance of mussel larvae over other species.