Lagosta: aquicultura como ferramenta para sustentabilidade e preservação do recurso

Abstract

The causes of drop and fluctuations in the production of spiny lobster producing countries are mainly the over-exploitation of stocks due to the fact that the management of these is being done unsustainably. Brazil is going through management problems in the lobster fishery, which results in difficulties, especially in artisanal fisheries. The aim of this work is to propose aquaculture as a tool for sustainability and preservation of lobster in Brazil. Lobster cultivation research of the Panulirus argus species was conducted in BioAqua (Parnaíba/ UFPI). Initially, a study was developed to determine the layout of a laboratory for research in biotechnology and marine aquaculture. Afterwards, an experiment with transport of lobster juveniles was performed using four replications for each treatment (T-I: control, T-II: ascorbic acid+macroalgae; T-III: macroalgae, and T-IV: ascorbic acid) and two different densities (20 and 25 ind./ container), in a completely randomized block design. Tests with water management were performed with three different treatments (TA: without exchange water; TB: 100% weekly exchange water, and TC: without exchange of water with added probiotic) and tests with different food with four treatments (T-1: Artemia; T-2: shrimp; T-3: mussel, and T-4: Artemia+shrimp+mussels). In the growth experiment in recirculation system, physical and chemical variables of the water were controlled, being analyzed the growth performance of lobsters, cultivated with initial density of 20 ind. m-3. Cultivation was also carried out using different types of shelters (Treatment I: bricks, and treatment II: PVC fittings), also in recirculation system. The layout was determined and implemented with two recirculating systems, each with six cultivation tanks and filtration system, a system for cultivation in a bioassay which can be cultivated simultaneously 288 juveniles, a room for biosafe culture and a system for receiving animals and water storage. The transportation of juvenile P. Argus proved viable, requiring the use of equipment for aeration and a plastic container with a capacity of 15 L with 50% of the volume being seawater, for transporting between 200 and 300 g of lobster, in treatments with density of 20 ind./ container there was no mortality. However, the treatments with 25 ind./ container, the average mortality was 0.5 ind./ treatment, but there was no statistical difference between them. Regarding the comparison of treatments with different managements of water, the highest survival and biomass growth rate were obtained in T-B treatment with 97.92 and 21.77%, respectively. Yet the highest growth rate was obtained in T-A treatment. In the experiment with food testing, T-3 treatment animals showed the highest survival rate of 95.83%, with greater rate of increase of biomass and growth achieved by treatment with T-4 23.84 and 4.66%, respectively. There were no statistical differences among the treatments with different management of water and food. In the growth experiment survival was 65.83%, the increase in biomass was 302.44% with an increase in the total length of 58,04% in 126 days of cultivation. In cultivation using different shelters, treatment I, had a survival rate of 81.67%, biomass gain of 316% or 30.87 g, and an increase in the total length of 34.48 mm or 54.98% throughout the cultivation. In treatment II, the survival rate was 70.00%, the biomass gain was 329.82% and 33.18 g, and the increase in the total length was 37.95 mm or 60.61% throughout the cultivation, with no statistical difference between treatments for all variables. Despite the difficulties due to their biology, what makes difficult the cultivation of all phases of the life cycle in captivity, the advancement of aquaculture is promising in some countries that produce lobster through fishery, since they are able to benefit from their own fishing, through restocking, as well as through their own aquaculture production, to meet part of the market demand.