Effects of shelter types and feeding rates on culture performance, shelter preference and feeding behaviour of spiny lobster Panulirus ornatus juveniles under laboratory conditions

Abstract

Spiny lobsters, <i>Panulirus ornatus</i>, are a highly valued crustacean worldwide, with strong demand and high prices making it important for fisheries and aquaculture economies. This study examined the effects of shelter types and feeding rates on rearing performance (which includes growth in weight and carapace length, survival, moulting frequency, shelter preference and feeding behaviour) in early juvenile spiny lobster, <i>P. ornatus</i> in two subsequent tank experiments. In experiment 1, groups of five juveniles (approx. 16 g) were reared separately in replicated tanks (200 litres) with different shelter types (bundled nets vs pipes vs no shelter as control). After 60 days, survival was higher in the bundled net treatment (73%) than in the pipe treatment (67%) and control (33%). However, survival and other rearing performance parameters did not differ significantly among shelter types (P &gt; 0.05). In experiment 2, shelter preference among early juveniles (<1 g) were further tested in rectangular tanks (20 litres) with both shelter type (bundled nets and stacked pipes) provided. In addition, different feeding rates using fresh mussel meat were tested: FR₁₀, FR₂₀ and FR₃₀, corresponding to 10, 20 and 30% of mean body weight per day. Results showed that young lobsters strongly preferred bundled net shelters (80% occupancy) vs pipes (20%). Feeding rate significantly affected growth, with FR₃₀ resulting in the highest gain in weight and carapace length. There was a strong positive correlation between mean body weight and daily feed consumption (P = 0.001). Nocturnal feeding behaviour was validated, as lobsters significantly consumed more food at night (81%) than during the day (69%) (P = 0.001). These results confirmed the importance of providing complex shelters, like bundled nets and optimising feeding regimes (30% of body weight per day, with a higher proportion at night) for improving productivity in the nursery rearing of spiny lobsters.