Increased reproductive opportunity: a potential benefit of seasonal aggregation for a little-gregarious and highly sedentary spiny lobster

Abstract

The spiny lobster Panulirus guttatus is a highly sedentary, obligate reef-dweller that exhibits a low degree of gregariousness yet reproduces year-round. Previous laboratory studies revealed that these lobsters were significantly attracted to scents released by conspecifics during a 'high reproductive activity' period (HRA, Â60% of ovigerous females on average) but not during a 'low reproductive activity' period (LRA, Â20%), suggesting that becoming more closely distributed at the right time may increase reproductive opportunities for these lobsters. We tested this hypothesis in the field. We marked all crevices harbouring P. guttatus lobsters ('dens') on two isolated coral reef patches over six consecutive sampling periods (three during an LRA and three during the ensuing HRA) and recorded the number, sex and size of lobsters in each den. Dens marked at a given time were considered as harbouring zero lobsters at previous times. For each site, a model selection based on parameters of the negative binomial distribution showed that m (mean lobsters/den) varied little over time but that k (dispersion parameter) decreased across the LRA and remained low (indicating a more clumped distribution) across the HRA. These trends in aggregation were further confirmed by values of Lloyd's 'patchiness', supporting the hypothesis that seasonal aggregation increases reproductive opportunities for P. guttatus. However, the tendency to aggregate appeared to be modulated by density and mean size of lobsters, which differed with site. These findings have potential implications for exploited P. guttatus populations and invite further study of the complex behaviours that characterize sedentary lobsters.

Metamorphosis of spiny lobsters (Panulirus argus and Panulirus guttatus) in the Yucatan Current as inferred from the distribution of pueruli and final stage phyllosomata

“…The former sustains valuable fisheries across the region, whereas the latter is a much less important resource due to its smaller size and habitat specialization. Although both species reproduce year‐round, P. argus exhibits a major reproductive peak in spring and a minor peak in autumn (Padilla‐Ramos and Briones‐Fourzán 1997), whereas P. guttatus shows a decrease in reproductive activity during late summer (Briones‐Fourzán et al 2013). The larval phase of P. argus comprises 10 phyllosoma stages, with an estimated duration of 5–9 months (Goldstein et al 2008), and the puerulus of this species is rather small (~ 6 mm carapace length [CL] on average) (Martínez‐Calderón et al 2018).…”

Lobster research integrated: From biology to management

“…Five papers on spiny lobsters from the Caribbean and Australia begin with a record of mechanisms of mate choice (Robertson & Butler 2013; contr. 7), followed by a behavioural study of seasonal aggregation including a model for management (Briones-Fourzán et al 2013;contr. 8), a tag and release programme evaluated by a model feeding into management (Ley-Cooper et al 2013;contr.…”