ECOLUBAL – Research and analysis of the future prospects for the sustainable reintroduction of organic sea bass (Dicentrarchus labrax) in the Albufera of Valencia.
Pleamar program
The project has consisted of the development of research based on the pilot trial of organic sea bass growth in the Albufera de Valencia to evaluate its technical, environmental and economic feasibility. The trial has been carried out on a plot of 5000 m2, owned by the Community of Fishermen of El Palmar, located on the left bank of the Sequiota (channel that connects the lake with the sea), currently occupied by reeds, but which in the past was flooded, and which has required prior cleaning and conditioning. establishing a raft for the release and growth of sea bass, protected with nets to prevent birds from predation on fish.
The production has been extensive, with a low density, in the order of 0.25 kg/m2 maximum at the end of the production process, starting from 1 fry per square meter, with an initial average weight of 25-50 g. A daily flow of water renewal has been established for oxygen supply and an emergency aeration system. The feeding of the sea bass has been based on natural productivity complemented with organic feed, formulated based on ingredients from organic agriculture and aquaculture, and manufactured by cooking-extrusion to guarantee its stability and digestibility to reduce waste, at the Universitat Politècnica de Valencia. Likewise, laboratory tests have been carried out at the UPV to optimise the organic feed in the final phases, the most problematic due to the waste generated.
At the end of the production process, the amount of organic waste produced by the sea bass has been evaluated, based on water analysis and a nitrogen and phosphorus balance, in order to guarantee environmental quality. Likewise, different zootechnical parameters have been calculated, (growth, feed rate, conversion rate, etc.), necessary for an economic evaluation of the production of organic sea bass under extensive conditions, based on production costs and sales price.
Finally, an analysis of the sensory quality of organic sea bass meat has been carried out to estimate its acceptance by consumers.
Line of action:
Marine ecosystemsStatus:
FinalizadoExecution date:
2017General Objective:
Local innovation in extensive aquaculture of organic sea bass.
Specific objectives:
- Technical feasibility of reintroduction and growth of organic sea bass in Albufera.
- Environmental viability of reintroduction and growth of organic sea bass in Albufera.
- Economic viability of reintroduction and growth of organic sea bass in Albufera.
- Protection of the environment and recovery of aquatic biodiversity and enhancement of ecosystems.
- Development of organic diets.
- Increase employment and territorial cohesion. Involve all citizens and fishermen.
The results of the project do not confirm the technical, environmental and economic feasibility of reintroducing organic sea bass (Dicentrarchus labrax) in the Albufera de Valencia, but this project made it possible to make progress in achieving the objective.
The cleaning and adaptation of the pond for the release and growth of sea bass has been carried out. A total of 2,290 8.5-gram juveniles and 274 54-gram juveniles were reintroduced, with a total density of 1 fish/m2. The water quality of the growth pond was evaluated and biological productivity (benthic fauna and phytoplankton) and interaction with avifauna were controlled. From the data obtained from dissolved oxygen, drops in levels below tolerance of sea bass were detected during the night, which may have become a limiting factor in growth.
Feeding tests were carried out with organic feed. In addition, three experimental feeds were prepared, based on ingredients of organic origin, and with different levels of sustainable fishmeal: reduction of 25% and 30% and an increase of 35%.
The results show no statistical differences in growth or feed conversion between organic feed with 30% fishmeal, versus non-organic control. By contrast, a reduction in fishmeal by up to 25% led to reduced growth, and an increase to 35% showed no improvement.
It can be concluded that the feeding of sea bass up to commercial sizes of 350 grams can be carried out with organic feed, without reducing production parameters.
ECOLUBAL – Research and analysis of the future prospects for the sustainable reintroduction of organic sea bass (Dicentrarchus labrax) in the Albufera of Valencia.
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