Proceedings of a workshop on Florida Spiny Lobster Research and Management, 24 August 1984

Agenda, abstracts, bibliography of recent literature on spiny lobsters, and list of participants. Workshop held at the Florida State University Marine Laboratory, 24 August 1984. (25pp. W.F. Hernkind (ed

Spiny lobster recruitment in South Florida: quantitative experiments and management implications

Understanding recruitment and identifying factors critical to that process are imperative if adult spiny lobster Panulirus argus stocks are to be conserved and properly managed. The goal of our research has been to obtain ecological information linking inshore postlarval spiny lobster recruitment to later life stages, thereby providing the basic framework for assessing and predicting adult stock. Since 1983, we have investigated various aspects of spiny lobster recruitment including: postlarval time-to-metamorphosis, postlarval/juvenile habitat selection and selection cues, postlarval/juvenile crypticity and susceptibility to predation, juvenile food preference and emigration, juvenile sociality, and the effect of habitat degradation (i.e., siltration) on postlarval/juvenile habitat selection and mortality. From this research we have established many of the basic biological and ecological determinants of the so-called missing stage of the spiny lobster (i.e., settlement through first 3-4 months of benthic life). Currently, we are conducting quantitative field experiments evaluating: 1. The relationship between surface collector catch (a standard measure of recruitment), postlarval settlement in algal clumps, and benthic juvenile abundance, and 2. The relative importance of settlement versus habitat carrying capacity in determining local lobster abundances. This research is ongoing, but preliminary results suggest that in Florida Bay: 1. Settlement is patchy and highest near the keys 2. Surface collectors are poor indicators of local settlement or recruitment 3. Suitable Habitat may Limit recruitment to the postalgal juvenile stage more than settlement

Habitat use and population biology of Bahamian spiny lobster

The spiny lobster Panulirus argus is extremely important both for basic scientific research (Davis, 1980) and the seafood industry. Despite the economic significance of Bahamian lobsters, their ecology has been the subject of limited study. Investigators have recorded fishery information (Smith, 1948, 1951), mass migration (Herrnkind and Kanciruk, 1978; Kanciruk and Hermkind, 1978; Hcrmkind, 1980), autumnal reproduction (Kanciruk and Herrnkind, 1976), commercial size composition (Simpson, 1976), life history and ecology of juveniles, and experimental fishing techniques (Waugh and Waugh, 1977; Waugh, 1980). (...) We report here on a 10-month (Sept, 1979-June, 1980) study of Panulirus argus in the region of Lee Stocking Island, north of Great Exuma Island. Size distribution, habitat, reproduction, and molting cycles are emphasized.https://scholarworks.wm.edu/vimsbooks/1141/thumbnail.jp

Factors Regulating Settlement and Microhabitat Use by Spiny Lobsters Panulirus argus

Clumps of highly-branched red algae Laurencia spp. serve as important settling habitat for postlarval spiny lobsters Panulirus argus and as residence for early benthic-stage juveniles. Given choice between the 2 most abundant macrophytes in Florida Bay, Laurencia spp. and the seagrass Thalassia testudinum, postlarval and juvenile lobsters chose Laurencia spp. Postlarvae apparently use intricate algal architecture as a cue for settlement, whereas juveniles use both architecture and food abundance in selecting habitat. In tethering experiments, predation on juvenile lobsters was very high on open sand, much reduced in algal clumps and seagrass, and lowest in dense algal meadows. Predation rates were similar day and night both on open sand and in vegetation. Most lobsters vacated algal clumps located within continuous algal meadows overnight, at a rate significantly higher than that from isolated algal clumps. We suggest that algal clump distribution, postlarval settling behavior, and juvenile interpatch movement and mortality contribute to the highly dispersed distribution and locally sparse abundances of early benthic juveniles

Are Artificial Witham Surface Collectors Adequate Indicators of Caribbean Spiny Lobster, Panulirus argus, Recruitment?

Understanding the local dynamics of Caribbean spiny lobster (Panulirus argus) postlarval influx, settlement, and recruitment may be essential for the responsible management of this important and heavily exploited resource. Most lobster recruitment research programs in the Caribbean employ derivations of the Witham -type surface collector to monitor postlarval (puerulus) lobster influx. However, the relevance of data obtained from surface collectors with respect to the estimation of actual puerulus influx, settlement, or recruitment to subsequent benthic juvenile stages remains untested. We investigated that relevance on regional (i.e., tens of kilometers) and local (i.e., tens of meters) scales by examining the quantitative relationships between the following: Surface collector catch of pueruli Planktonic density of pueruli Benthic settlement of pueruli Recruitment to the postalgal juvenile stag

The Effects of Siltation on Recruitment of Spiny Lobsters, Panulirus argus

Fewer juvenile pinry lobsters were found in areas of the Florida Keys where their primary habitat was heavily silted as compared with similar, less silted habitat. Several hypotheses explaining this relationship were tested, and the time-to-metamorphosis was compared for settling pueruli within silted and nonsilted algae stands. Limited postlarval settlement and avoidance of silted algal habitats by juveniles, probably accounts for the paucity of young lobsters in heavily silted sites. In addition, although juvenile lobsters are nonselective predators, lower prey availability in silted algae probably promotes transciency which, in turn, causes increased mortality by predation while juveniles are exposed

Factors Affecting the Recruitment of Juvenile Caribbean Spiny Lobsters Dwelling in Macroalgae

In south Florida, Caribbean spiny lobsters (Panulirus argus) settle and spend their first few months in macroalgae or seagrass. After a few months, these \u27\u27algal-phase\u27\u27 juveniles emerge from vegetation and, as \u27\u27postalgal-phase\u27\u27 juveniles, seek refuge in crevices, often dwelling in groups. The importance of crevice shelters in determining the abundance of postalgal-phase juvenile spiny lobsters has been studied but we know little about the processes affecting lobster distribution and survival during their cryptic algal-dwelling phase. We found that postlarval supply varied independently of changes in the structure of macroalgal settlement habitat. For this reason, postlarval supply alone can not reliably predict local settlement density. Changes in the size of macroalgal patches in particular tend to increase the variability in settlement density among locations and times. Field and mesocosm experiments indicate that social interactions and individual movements are unlikely to alter the general distribution of algal-phase lobsters established at settlement. But if algal-phase lobsters are aggregated at scales \u3c1 \u3em(2) (e.g., due to patchy settlement), they experience higher mortality than non-aggregated lobsters, as revealed in field experiments where lobsters were tethered alone or in pairs and at varying inter-individual distances. Field manipulations of settlement density indicate that recapture (survival) of microwire tagged algal-phase juveniles is positively associated with features of the habitat that affect lobster density (e.g., site area, macroalgal patch size), but survival and growth of lobsters are unrelated to artificially manipulated settlement density. Collectively, these results imply that the population dynamics of juvenile P. argus dwelling in macroalgae are not typically regulated by density-dependent processes, although density-dependent predation may be locally important in patches when settlement is episodically high

Regional Characterisation of Hard-Bottom Nursery Habitat for Juvenile Caribbean Spiny Lobster (Panulirus argus) Using Rapid Assessment Techniques

Shallow, hard-bottom habitat constitutes approximately 30% of the coastal waters of south Florida, United States, yet it is a chronically understudied feature of the marine seascape in this region. In this study, we characterised the general biogeographic and structural features of shallow benthic hard-bottom communities in the Florida Keys, and related those to the abundance of juvenile Caribbean spiny lobster (Panulirus argus), the target of one of Florida\u27s most economically valuable fisheries. We used rapid assessment techniques to survey more than 100 hard-bottom sites in the Florida Keys to estimate the percentage bottom coverage of vegetation (seagrass and macroalgae) and the abundance of sponges, octocorals, hard corals, and other crevice-bearing structures, as well as the abundance of juvenile lobsters. Using a multivariate statistical approach, we evaluated the relationship between habitat and size-specific juvenile lobster abundance and quantitatively verified the existence of six generally accepted biogeographic subregions. Although the types of hard-bottom shelters used by juvenile lobsters varied somewhat among these subregions, in all regions, branching-candle sponges and octocorals were under-used by lobsters, whereas loggerhead sponges, coral heads, and solution holes were over-used (i.e., used more frequently than expected based on their availability). There was also an ontogenetic transition in the shelter preference of juvenile lobsters; small juveniles tended to occupy a variety of sponges, whereas large juveniles preferred hard structures such as coral heads and solution holes. This study yields the first quantitative biogeographic description of hard-bottom communities of the Florida Keys, and confirms the suspected relationship between the structural features of hard-bottom habitat and the value of these communities as nurseries for juvenile spiny lobster