Common DENTEX

Person in charge

Eric Durieux

Problematic issues

As a top predator, the Dentex dentex (or Common dentex) holds a key position within the Mediterranean ecosystems. Moreover, this species is particularly targeted by both commercial and recreational fishing. The Common dentex is the only species of Sparidae classified as “vulnerable threatened” in the Mediterranean. At the same time, the Common dentex is well known and highly valued in Corsica, thereby creating a favourable context for the introduction of a new species on the Corsican fish market.

Objectives

This project focuses on the zootechnical aspect with the objective of improving knowledge on the biology and the breeding of this species in a context of production diversification in the Corsican marine fish farming sector. In an approach of sustainable management of fish resources in Corsica, work has already been carried out concerning the “halieutic ecology” aspect of this species and is currently continuing within the framework of the DACOR, MOONFISH, MoPaMFish and BEHAVIOURAL MODELISATION projects.

Description

The dentex is an iconic coastal marine fish and heritage of the Mediterranean basin with an important economic interest for small-scale professional fishing, particularly in Corsica. The dentex is also notably targeted by recreational fishing, but there is no real estimation or the amount of this catch. Dentex is the only Sparidae species classified as vulnerable in the IUCN Regional Assessment for the Mediterranean. In addition, as a top predator, the dentex occupies a key position at the top of the trophic pyramid and is therefore potentially an indicator species for the very structure and functioning of the coastal ecosystem on which it depends. The market value and biological characteristics of dentex make them a promising species for the diversification of Mediterranean marine fish farms. Indeed, among the potentially fish farming Mediterranean species, those belonging to the Sparidae family are by far the most strongly represented. Dentex dentex, while not yet the most common Sparidae in fish farming, seems to be one of the most promising for the future, particularly because of its breeding potential. This project is thus designed to improve fish hatchery techniques and diversify production towards new local species by studying the biology and breeding of this particularly species. The objective of this program is to control the different phases of this species ‘life cycle in captivity. Through this action unit, UMS STELLA MARE supports the Corsican fish farmers’ union in its diversification. Moreover, the zootechnical results can also be used for the preservation of the dentex.

Steps to be taken

A « fisheries ecology » section aims to provide information on the exploitation and ecology of the common dentex in order to contribute to the sustainable management of the species. This section of the project will consist of the following actions:

• Evaluation of the exploitation of the Common dentex by commercial and recreational fishing in Corsica.
• Study of the biological parameters and demographic structure of the dentex population in Corsica (size / age classification, weight, sex ratio)
• Analysis of the territorial distribution of the Common dentex population around Corsica using natural markers (otoliths and parasites)
• Analysis or the demographic distribution of the Common dentex around Corsica and over its entire area of distribution (Mediterranean and near the Atlantic) using genetic markers (microsatellites)
• Study of the behaviour patterns and how the habitat is used, by electronic tagging (activity rhythm, movements, spawning area, ...)

The “zootechnical” aspect of the programme aims to improve knowledge on the biology and breeding of this species in a context of diversification of the production in the marine fish farming sector in Corsica. This section of study will be divided into the following actions:

• Usage of wild spawners from the Corsican coast for the breeding
• Evaluation of the optimal conditions of the breeding and spawning stages
• Enhancing existing larval development protocols for this species in order to limit the mortality due to cannibalism
• Pre-growing of juveniles
• Estimation of the genetic diversity of common dentex spawners and their offspring at different stages in fish farming, relative to the wild population around Corsica