Introduction
The contribution of aquaculture to worldwide seafood production has seen a steady increase over the past decades, becoming a significant economic activity for many nations. In the Autonomous Region of the Azores characterised, as other outermost regions, by their remoteness, insularity, small size, difficult topography and climate, economic dependence on a few products, aquaculture is considered an important area for the diversification of activities linked to the sea, in a quest for new business areas which do not conflict with efforts to preserve marine natural resources (COM, 2012). Although aquaculture in the Azores has a recognized potential to be implemented (Pham et al. 2008), there is to date no commercial production. The need to orientate the aquaculture activities in this region and to overcome the general worries about overfishing and wild resources sustainability led in 2008 to the "First International Workshop on Developing a Sustainable Aquaculture Industry in the Azores" (Pham et al. 2008). Among the relevant factors identified were the needs of more information and the establishment of a dedicated aquaculture research facility focusing on one or more prioritized species. Indeed, starting from 2012 the research activities of AquaLab, a small and versatile research facility, began focusing the attention on rearing of the giant barnacle Megabalanus azoricus and of the European abalone Haliotis tuberculata coccinea.
Megabalanus azoricus
Only, since 2007, small-scale pilot projects have explored the potential of the giant barnacle, Megabalanus azoricus, for the development of large-scale aquaculture operations (Isidro et al. 2009). Some efforts have been made in respect to the development of production technologies in suspended culture systems but still one of the main challenge of commercial scale 'acorn' barnacle production is to ensure a sufficient quantity of seed all year round (Lopez et al. 2010). In this context work has been focused on the development of larval rearing procedures (Nunes et al. 2017). A protocol has been established to obtain nauplius (instar II) to be subjected to feeding tests with different microalgae diets. Among the microalgae tested (Chaetoceros sp., Chloromonas sp., Dunaliella sp., T-Isochrysis sp. and Skeletonema sp.) the mixed-diet Skeletonema sp. with T-Isocrysis sp. showed the highest survival percentages ranging from 79.7 to 85.7% with 69.7-80.0% of nauplii in stage VI after 11 days of rearing. Settlers were found on the collectors after 25 days, at 20±1°C. However recruitment was less than 1% and, although preliminary results showed no settlement preference towards different collectors, more studies need to be developed in this direction to establish a mass production and settlement on defined substrates.
As part of the refinement of seed production techniques, research at AquaLab included also the development and use of molecular genetic markers (Molecular Ecology Resources Primer Development Consortium et al., 2013) as an essential tool to address and solve questions related to genetic resource management. Information on the scale of genetic diversity and population structure of this species have been provided using seven microsatellites markers on 300 samples from six out of nine islands of the Azores archipelago. Results suggest that genetic risks associated with the giant barnacle potential production scheme should be taken into account in a future management plan delimiting, as precautionary measure, this culture at a single island or at groups of islands (De Girolamo et al. 2017).
Haliotis tuberculata coccinea
H. tubercolata coccinea is another potential species for aquaculture development in the Azores islands. Due to its high commercial value, declining natural stocks and severe bacterial disease occurred in Europe, H. tuberculata has been suggested as one of the most suitable species for a sustainable development of aquaculture in the region. Food preferences differ among abalone species around the world, varying with habitat and food availability. Considering the scarce information available on the feeding preferences in the Azores, we started to perform feeding trials to assess the suitability of two green algae Ulva rigida, Ulva intestinalis and the brown algae Sargassum vulgare, as potential feed for the culture of juvenile abalone. Trials gave us not only the direction about potential feed for abalone culture but also allow us to acquire experience on rearing conditions of this species (Paulino et al. 2017). More recently the research has been directed towards reproduction trials and early growth under experimental conditions.
References
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