Workpackages

The aim of this part of the workplan will comprise the identification, at specific level, of the ecto- and endometazoan parasites recovered from horse mackerel collected in the North-east Atlantic and Mediterranean Sea, as well as their possible use as "biological tags” of the existence of different stock units of horse mackerel and the evaluation of their infection levels in different samples of horse mackerel throughout its geographic distribution. The aim of the proposal is to use the recovered and identified parasites of Trachurus trachurus throughout its range as "biological markers” of horse mackerel stock identification and status. Parasites repeatedly have been used to study populations and migration of marine fishes. In marine fish the most frequently used as tags have been the larval anisakid nematodes of the genera Anisakis, Pseudoterranova and Hysterothylacium .

To achieve this objective, traditional morphological analysis will be carried out in the case of monogeneans, digeneans, cestodes and crustaceans parasites recovered in T.trachurus collected from the selected 20 localities, to identify them at specific level. A statiscally siginificative number of specimen per each locality, at least 100 specimen will be collected for parasitological survey. All the samples taken will be sent to Participant 07 who will develop the morphological identification of parasites in collaboration also with Participant 02. Genetic analysis by means of multilocus electrophoresis will be carried out in the case of anisakid nematodes by Participant 04. Participant 07 will send all the anisakid nematodes recovered to the Participant 04 (see diagram for work organization). The lack of diagnostic morphological characters in the larval forms of anisakid nematodes belonging to the genus Anisakis and the presence of sibling species within morphospecies of the genus Anisakis, make their identification at specific level, impossible by means of traditional morphological studies, and therefore, their identification will be performed by the use of multilocus electrophoresis (MAE).

The parasitic infections in different horse mackerel samples will be evaluated using the epizootiological parameters of prevalence, abundance and intensity of each parasite infection and the appropriate statistical tools for testing the differences.

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