Juvenile Caribbean Spiny Lobsters Research Articles

Alterations in the gut-associated microbiota of juvenile Caribbean spiny lobsters Panulirus argus (Latreille, 1804) infected with PaV1

The spiny lobster Panulirus argus (Latreille, 1804) is currently affected by an unenveloped, icosahedral, DNA virus termed Panulirus argus virus 1 (PaV1), a virulent and pathogenic virus that produces a long-lasting infection that alters the physiology and behaviour of heavily infected lobsters. Gut-associated microbiota is crucial for lobster homeostasis and well-being, but pathogens could change microbiota composition affecting its function. In PaV1 infection, the changes of gut-associated microbiota are yet to be elucidated. In the present study, we used high-throughput 16S rRNA sequencing technology to compare the bacterial microbiota in intestines of healthy and heavily PaV1-infected male and female juveniles of spiny lobsters P. argus captured in Puerto Morelos Reef lagoon, Quintana Roo, Mexico. We found that basal gut-associated microbiota composition showed a sex-dependent bias, with females being enriched in amplicon sequence variants (ASVs) assigned to Sphingomonas, while males were enriched in the genus Candidatus Hepatoplasma and Aliiroseovarius genera. Moreover, the alpha diversity of microbiota decreased in PaV1-infected lobsters. A significant increase of the genus Candidatus Bacilloplasma was observed in infected lobsters, as well as a significant decrease in Nesterenkonia, Caldalkalibacillus, Pseudomonas, Cetobacterium and Phyllobacterium. We also observed an alteration in the abundances of Vibrio species. Results from this study suggest that PaV1 infection impacts intestinal microbiota composition in Panulirus argus in a sex-dependent manner.

Do ecological characteristics drive the prevalence of Panulirus argusvirus 1 (PaV1) in juvenile Caribbean spiny lobsters in a tropical reef lagoon?

PaV1 is a pathogenic virus found only to infect Caribbean spiny lobsters Panulirus argus, a major fishing resource. P. argus is a benthic mesopredator and has a complex life history, with several ontogenetic habitat changes. Habitat characteristics and species diversity of surrounding communities may have implications for disease dynamics. This is of more concern for juvenile lobsters, which are more susceptible to PaV1 and are far less mobile than adult lobsters. We targeted a population of juvenile P. argus in a reef lagoon in Mexico, where PaV1 was first observed in 2001. Prevalence has been since irregularly assessed, but in 2016 we began a more systematic assessment, with two sampling periods per year (June and November) in three different zones of the reef lagoon. To examine the relationship between PaV1 prevalence and potential ecological determinants, we assessed habitat complexity, cover of different substrates, and invertebrate community composition in all zones during the first four sampling periods (June and November 2016 and 2017). Habitat complexity and percent cover of some substrates varied with zone and sampling period. This was the case for seagrass and macroalgae, which nevertheless were the dominant substrates. The invertebrate community composition varied with sampling period, but not with zone. Probability of infection decreased with increasing lobster size, consistent with previous studies, but was not affected by zone (i.e., variations in ecological characteristics did not appear to be sufficiently large so as to influence prevalence of PaV1). This result possibly reflects the dominance of marine vegetation and suggests that lobsters can be sampled throughout the reef lagoon to assess PaV1 prevalence. Prevalence was higher in only one of seven sampling periods (November 2017), suggesting that the pathogen has leveled off to an enzootic level.

Annual juvenile recruitment of spiny lobsters, Panulirus argus (Decapoda, Palinuridae), in a shallow seagrass bed and a deeper hard bottom off western Puerto Rico

We found 158 juvenile Caribbean spiny lobsters (Panulirus argus) recruiting over a year into 10 artificial shelters in shallow (2-3 m) seagrass beds, but none recruiting into 10 shelters on deeper (approximately 10 m) hard bottom. Spiny lobster juveniles were observed at 10 m or greater depth in submerged fish cages. They may have been strained out by currents rather than naturally recruiting. A large number of these cages inshore could impede natural lobster recruitment. One of the shallow shelters recruited most (85/158) of the juveniles and two shelters recruited most of all (118/158). With no discernable natural habitat difference, we assume that early recruitment into those shelters and the “guide effect” may have been responsible for these preferences. Previous Caribbean studies found the maximum settling periods of juveniles in August to December. Our results were similar with the exception of having more recruits one month later (August to January). Shelters with covers had more juveniles than those without covers; however, this result was largely due to the preponderance of juveniles in one shelter.

Are juvenile Caribbean spiny lobsters (Panulirus argus) becoming less social?

Abstract Caribbean spiny lobsters are one of the most commercially important fisheries due in large part to their highly gregarious nature that facilitates their harvest by the use of traps or aggregation devices containing conspecifics. Aggregation in this species has been shown to be due to strong attraction to conspecific chemical cues that influence movement rates, discovery of crevice shelters, and den sharing behaviours. Although aggregation has been shown to have many potential benefits (reduction in exposure time and predation risk), it may also have significant costs as well (increase in predator encounters, disease transmission, and fishing mortality). We compared the results of three published and three unpublished Y-maze chemical cue choice experiments from 1996 to 2012 to determine if there has been a decrease in conspecific attraction by early benthic juvenile Caribbean spiny lobsters (15–55 mm carapace length, CL). We found that attraction to conspecific chemical cues decreased since 2010 and was significantly lower in 2012. Lobsters showed individual variation in conspecific attraction but this variation was unrelated to size, sex, or dominance status. We also found localized regional variation in conspecific attraction with lobsters from high shelter/high disease areas showing significantly lower conspecific attraction than those from low shelter/low disease areas. Given that conspecific attraction varies among individuals and potentially increases mortality through either natural (increased disease transmission) or fishery-induced (attraction to traps) mechanisms, we should play close attention to this loss of conspecific attraction in juvenile lobsters. Future studies should investigate both the causation and the ecological significance of changes in conspecific attraction in regions that vary in intensity of disease (PaV1) and fishing pressure.

Behavioral response to habitat loss in juvenile spiny lobsters

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 521:117-128 (2015) - DOI: https://doi.org/10.3354/meps11125 Behavioral response to habitat loss in juvenile spiny lobsters Katherine A. Heldt1,3,*, William C. Bridges Jr.2, Michael J. Childress1 1Department of Biological Sciences, Clemson University, Clemson, South Carolina 29634, USA 2Department of Mathematical Sciences, Clemson University, Clemson, South Carolina 29634, USA 3Southern Seas Ecology Laboratories, School of Earth, Environmental, and Landscape Sciences, The University of Adelaide, Adelaide 5006 SA, Australia *Corresponding author: katherine.heldt@adelaide.edu.au ABSTRACT: Understanding behavioral changes is important when examining the impacts of rapid environmental change, particularly when critical resources such as protective shelters become locally limited during habitat loss events. In portions of Florida Bay (Florida, USA), cyanobacterial blooms have reduced the availability of large sponges, an important shelter for juvenile Caribbean spiny lobster Panulirus argus. We examined whether juvenile lobsters from regions with and without sponge shelters differed in: (1) aggressive and gregarious behaviors; (2) den use, den sharing, and den fidelity before and after shelter loss; and (3) dispersal from sites with and without artificial shelters. In laboratory experiments where individuals were paired with similar-size conspecifics, habitat type had no influence on aggression and gregariousness, but larger lobsters were more aggressive and shared dens less frequently than smaller lobsters. When these same individuals were placed into groups of 20 in a mesocosm and exposed to shelter loss, individuals from habitats with sponges showed a greater decrease in den use and den sharing than individuals from habitats without sponges. After shelter loss, large lobsters decreased their den use, den sharing, and den fidelity more than small lobsters. When individuals were released at their point of capture in Florida Bay, large individuals were resighted less often than small individuals. This study suggests that lobsters from habitats without sponges may respond differently to future shelter loss and that size plays an important role in determining whether juvenile spiny lobsters share shelters or disperse. KEY WORDS: Caribbean spiny lobster · Social behavior · Panulirus argus · Aggression · Gregariousness · Sponge mortality Full text in pdf format PreviousNextCite this article as: Heldt KA, Bridges WC jr, Childress MJ (2015) Behavioral response to habitat loss in juvenile spiny lobsters. Mar Ecol Prog Ser 521:117-128. https://doi.org/10.3354/meps11125 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 521. Online publication date: February 17, 2015 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2015 Inter-Research.

Host behavior alters spiny lobster-viral disease dynamics: a simulation study.

Social behavior confers numerous benefits to animals but also risks, among them an increase in the spread of pathogenic diseases. We examined the trade-off between risk of predation and disease transmission under different scenarios of host spatial structure and disease avoidance behavior using a spatially explicit, individual-based model of the host pathogen interaction between juvenile Caribbean spiny lobster (Panulirus argus) and Panulirus argus Virus 1 (PaV1). Spiny lobsters are normally social but modify their behavior to avoid diseased conspecifics, a potentially effective means of reducing transmission but one rarely observed in the wild. We found that without lobster avoidance of diseased conspecifics, viral outbreaks grew in intensity and duration in simulations until the virus was maintained continuously at unrealistically high levels. However, when we invoked disease avoidance at empirically observed levels, the intensity and duration of outbreaks was reduced and the disease extirpated within five years. Increased lobster (host) spatial aggregation mimicking that which occurs when sponge shelters for lobsters are diminished by harmful algal blooms, did not significantly increase PaV1 transmission or persistence in lobster populations. On the contrary, behavioral aversion of diseased conspecifics effectively reduced viral prevalence, even when shelters were limited, which reduced shelter availability for all lobsters but increased predation, especially of infected lobsters. Therefore, avoidance of diseased conspecifics selects against transmission by contact, promotes alternative modes of transmission, and results in a more resilient host-pathogen system.

Review of Panulirus argus virus 1—a decade after its discovery

In 2000, a pathogenic virus was discovered in juvenile Caribbean spiny lobsters Panulirus argus from the Florida Keys, U.S.A. Panulirus argus virus 1 (PaV1) is the first naturally occurring pathogenic virus reported from lobsters, and it profoundly affects their ecology and physiology. PaV1 is widespread in the Caribbean with infections reported in Florida (U.S.A.), St. Croix, St. Kitts, Yucatan (Mexico), Belize, and Cuba. It is most prevalent and nearly always lethal in the smallest juvenile lobsters, but this declines with increasing lobster size; adults harbor the virus, but do not present the characteristic signs of the disease. No other PaV1 hosts are known. The prevalence of PaV1 in juvenile lobsters from the Florida Keys has been stable since 1999, but has risen to nearly 11% in the eastern Yucatan since 2001. Heavily infected lobsters become sedentary, cease feeding, and die of metabolic exhaustion. Experimental routes of viral transmission include ingestion, contact, and for newly settled juveniles, free virus particles in seawater. Prior to infectiousness, healthy lobsters tend to avoid diseased lobsters and so infected juvenile lobsters mostly dwell alone, which appears to reduce disease transmission. However, avoidance of diseased individuals may result in increased shelter competition between healthy and diseased lobsters, and greater predation on infected lobsters. Little is known about PaV1 outside of Mexico and the USA, but it poses a potential threat to P. argus fisheries throughout the Caribbean.

Nutritional indices of juvenile Caribbean spiny lobsters in a Mexican reef lagoon: Are changes over a 10-year span related to the emergence of Panulirus argus Virus 1 (PaV1)?

We compared two indices of nutritional condition, the relative weight of the digestive gland (RWDG) and the ratio of weight to carapace length (weight/CL ratio), of the first three benthic phases, algal juveniles (7–25 mm CL), postalgal juveniles (25–45 mm CL), and subadults (45–79 mm CL) of Caribbean spiny lobster ( Panulirus argus) dwelling in a shelter-poor reef lagoon before (1995) and after (2005) deployment of large artificial shelters (“casitas”) in 1998. To provide an experimental baseline, in 2005 we also conducted a laboratory experiment to assess the effect of starvation on both nutritional indices. Through 25-day trials, starvation significantly decreased the mean RWDG of all three juvenile phases, but did not affect their weight/CL ratios. In the field, casitas significantly enhanced juvenile lobsters relative to control sites and to prior values, but between 1995 and 2005 there was a significant decrease in condition of algal juveniles (both indices) and postalgal juveniles (only the RWDG), but not of subadults. These results would appear to counter previous findings that, for P. argus, food is not limiting and nutritional condition is not density-dependent. However, in 2000, a new pathogenic virus that has a distinct predilection for small juveniles, Panulirus argus Virus 1 (PaV1), emerged in the reef lagoon. Among other effects, this lethal virus causes a marked atrophy of the digestive gland. Through the laboratory trials and in the field, prevalence of visibly diseased individuals was highest in algal juveniles and lowest in subadults. These individuals were excluded from statistical analyses, but the disease progression may affect the digestive gland progressively given that newly infected lobsters take several weeks to become visibly diseased. Up to 2006, PaV1 had not significantly impacted lobster density on casita sites, but because P. argus is highly gregarious and transmission of PaV1 appears to be mainly by contact, futher investigation is required. These issues are relevant to enhancement of spiny lobsters and assessment of ecological impacts of marine diseases.

Developmental changes in the mouthparts of juvenile Caribbean spiny lobster, Panulirus argus: Implications for aquaculture

Light microscopy and video analysis were used to examine the mouthpart morphology and feeding behaviour of the Caribbean spiny lobster from puerulus (megalopal stage) (5–8 mm carapace length, CL) to adult (85 mm CL). Upon settlement the pueruli did not possess fully functional mouthparts, however, efficient feeding appendages appeared in the first instar juvenile (after the first moult from puerulus). From this stage the density, robustness and complexity of setation on the mouthparts, together with the size and calcification of the mouthparts increased progressively with the size of the lobster. The changes correlated well with previously observed ontogenetic changes in natural prey, from small and soft prey in early juveniles to large and well-armoured molluscs, crustaceans and echinoderms in late juveniles and adults. The efficiency of shredding and tearing food items, mostly with the second maxillipeds, increased concomitantly with lobster size, as did the ability of the mandibles to grind and process food. Based on morphological and behavioural observations it is recommended that formulated feeds for first instar juvenile lobsters should be small (1–2 mm in diameter), soft and pulpy in texture to maximise feed intake. For large juvenile lobsters (45–80 mm CL), food items should increase to 5–10 mm in diameter and be of firmer consistency. Differences in feeding behaviour between spiny lobster species suggest that formulated diets developed to be efficient in one species may not be directly transferable to other species.

Transmission of Panulirus argus virus 1 (PaV1) and its effect on the survival of juvenile Caribbean spiny lobster

The Caribbean spiny lobster Panulirus argus, an important fisheries species, is host to Panulirus argus virus 1 (PaV1), a lethal, unclassified virus--the first found in any species of lobster--prevalent in juvenile lobsters. We describe a series of laboratory experiments aimed at assessing the likely modes of disease transmission, determining the survival of lobsters relative to each transmission pathway and identifying potential alternate hosts. Given evidence for lower prevalence of PaV1 in large lobsters, the effect of lobster size on susceptibility was also examined. Results demonstrated that PaV1 can be transmitted to juvenile lobsters via inoculation, ingestion of diseased tissue, contact with diseased lobsters and--among the smallest juveniles--through water over distances of a few meters. Contact and waterborne transmission, the most likely modes of transmission in the wild, were less efficient than inoculation or ingestion. Nevertheless, about half of the smallest lobsters in contact and waterborne trials contracted the disease and died within 3 mo. Other decapods that co-occur with P. argus (e.g. spotted lobster P. guttatus, stone crab Menippe mercenaria, channel crab Mithrax spinosissimus) did not acquire the disease after inoculation with PaV1-infected hemolymph. Our results confirmed that PaV1 is highly infectious and lethal to juvenile P. argus, particularly early benthic juveniles in the wild, and, hence, is a threat to mariculture.

Ecological and physiological effects of PaV1 infection on the Caribbean spiny lobster ( Panulirus argus Latreille)

Pathogens can profoundly impact the ecology of the organisms they infect through changes in host behavior that influence demographic processes. For example, juvenile Caribbean spiny lobsters ( Panulirus argus Latreille) infected with the PaV1 virus ( Panulirus argus Virus 1) are avoided by their normally social conspecifics, which alters local spatial distributions and presumably rates of disease transmission. PaV1 infections are nearly always lethal, but prior to succumbing to the disease, infection may impact other host dynamics (e.g., movement, growth, or survival) that effect transmission of the virus. We used mark-recapture surveys and laboratory studies to determine the impact of PaV1 infection on lobster movement and physiological condition, and in turn, the effect of condition on susceptibility to infection. Significantly more healthy lobsters were recaptured than heavily diseased lobsters in 5-d mark-recapture surveys, indicating either greater emigration or greater mortality of infected lobsters. Results of a laboratory bioassay suggest that lobsters with early-stage infections moved at an equivalent rate to healthy lobsters, however, as infection progressed, lobsters inoculated with PaV1 moved less than healthy lobsters ultimately remaining sedentary. Infected lobsters captured in nature also had significantly lower hemolymph (blood) serum protein values, indicating poor physiological condition. However, poor condition did not predispose lobsters to greater risk of infection because prevalence was not different between starved lobsters and healthy lobsters challenged with PaV1. Although lobsters infected with PaV1 eventually become sedentary and of poor nutritional condition, during the early stages of infection they remain active and are thus capable of dispersing the virus throughout the population.

Circadian shelter occupancy patterns and predator–prey interactions of juvenile Caribbean spiny lobsters in a reef lagoon

The spiny lobster, Panulirus argus, is predominantly nocturnal, remaining inside shelters during the day and foraging outside at night, presumably to minimize predation risk. Predation risk generally decreases with increasing lobster size. Therefore, this study examined the hypothesis that size would influence this basic circadian pattern. Video cameras continuously recorded the shelter occupancy of juvenile lobsters (n = 72) having a carapace length (CL) of 30–62 mm that were tethered to shelters in a shallow reef lagoon. The lobsters’ shelter occupancy was 100% during the day, but declined linearly from shortly before sunset to a minimum of 50% shortly after midnight and then increased linearly, reaching 100% by 1 h after sunrise. The percent time the lobsters spent in the shelters followed a similar trend, but there was wide variability at night (0–100%) for individual lobsters. Lobsters left their shelters 2–30 times night−1, with a majority of excursions lasting 80 mm CL), which have a dusk/early evening peak in activity and leave the shelter for extended periods of time during the night. Furthermore, a minimum shelter occupancy in the middle of the night appears especially well adapted to avoid exposure to daytime predators. Videotaped observations also included interactions between lobsters and two dominant lobster predators, the triggerfish, Balistes capriscus, and the octopus Octopus cf. vulgaris. Lobsters responded differently to these predators: remaining in the shelter when attacked by a triggerfish and fleeing the shelter when attacked by an octopus. Triggerfish were nearly twice as likely to attack a lobster that was outside of the shelter than inside. Once under attack, however, a lobster had nearly the same chance of surviving if it was inside or outside. Results suggest that the patterns of shelter use and emergence change as lobsters grow, probably reflecting the interplay between perception of predation risk and the need to forage.

Enhancement of juvenile Caribbean spiny lobsters: an evaluation of changes in multiple response variables with the addition of large artificial shelters

Shortage of natural crevice shelters may produce population bottlenecks in juvenile Caribbean spiny lobsters (Panulirus argus), a socially gregarious species. We conducted a field experiment to test enhancement of a local population of juvenile P. argus with the addition of artificial shelters ("casitas") that mimic large crevices (1.1 m(2) in surface area and 3.8 cm in height). Changes in density and biomass of juvenile lobsters 15-50 mm carapace length (CL) were assessed with a multiple before-after control-impact (MBACI) analysis. Separate analyses were also conducted on small (15-35 mm CL) and large (35.1-50 mm CL) juveniles to assess size-related effects. First, we carried out 13 lobster surveys on nine fixed 1-ha sites over a shallow reef lagoon ("before" period). Then, we deployed ten casitas in each of five sites and left four sites as controls, and conducted 22 further surveys ("after" period). Deployment of casitas resulted in a sixfold increase in juvenile density (76% contributed by small and 24% by large juveniles) and a sevenfold increase in biomass (40 and 60%, respectively). Capture-recapture results revealed that enhancement was achieved not by promoting individual growth but by increasing survival, persistence, and foraging ranges of small and large juveniles. Casitas both mitigated shortage of natural shelter and increased sociality, allowing for cohabitation of smaller, more vulnerable juveniles with larger conspecifics that have greater defensive abilities. Casitas may help enhance local populations of juvenile P. argus in Caribbean seagrass habitats, typically poor in natural crevice shelters. The use of MBACI and the simultaneous assessment of multiple interrelated response variables may be a powerful analytical approach to test shelter limitation in other species and to examine the function of structural habitat in other systems.

Density-dependent population dynamics in juvenile Panulirus argus (Latreille): The impact of artificial density enhancement

The use of artificial structures to enhance marine animal populations, or as an aid to fishing, is widespread and increasing. While most investigators have studied the efficacy of artificial structure by measuring population abundance of the target species, or by comparison of the resulting community structure with that of natural communities, the effect of habitat enhancement on the processes creating such patterns is largely unknown. We enhanced density with the addition of artificial structures to examine the effect of local population density on the population dynamics (e.g., movement, mortality, and nutritional condition) of juvenile Caribbean spiny lobster ( Panulirus argus) at natural and habitat-manipulated sites in the Florida Keys (USA). We artificially enhanced lobster density using small, scattered crevice-bearing structures that mimicked the natural shelters sought by juvenile lobsters. Enhanced density had no measurable effect on juvenile lobster mortality from predation or nutritional condition (as measured by hemolymph refractive index), but it increased the short-term residency of juvenile lobsters. The gregarious nature of spiny lobsters coupled with access to abundant prey may make them robust to high population density.

The Adaptive Value of Aggregation among Juvenile Caribbean Spiny Lobster: An Evaluation Using Individual-Based Modeling

Abstract Ontogenetic changes in gregariousness by pre-reproductive animals, like that observed in juvenile Caribbean spiny lobsters (Panulirus argus), may be adaptive and reflect size-specific changes in the effectiveness of aggregation in promoting survival. Alternatively, aggregation may simply result from changes in the distribution or availability of suitable habitat structure, or from other behaviors that enhance survival. There are currently two hypotheses explaining the potential benefits of gregarious behavior in juvenile spiny lobsters, both of which focus on increasing survivorship by reducing predation pressure: the group benefit hypothesis and the guide hypothesis. The group benefit hypothesis argues that aggregations of juvenile lobsters reduce individual susceptibility to predators because groups are better able to fend off attackers or benefit by dilution of risk. The guide hypothesis suggests that aggregation is a consequence of shelter seeking behavior, in which individuals searching for ...

The guide effect influence on the gregariousness of juvenile Caribbean spiny lobsters

Many animals are gregarious and potentially benefit from the presence of conspecifics. We examined both den finding and den sharing by vulnerable juvenile Caribbean spiny lobsters, Panulirus argus, and compared three functional explanations of why lobsters might benefit from being gregarious. Lobsters sharing dens did not have higher survival than those in dens by themselves, suggesting that cooperative group defence may not be important at this life history stage. Lobsters in areas of high conspecific density did not have higher survival than those in areas of low density, suggesting that the dilution effect may not be important either. Den sharing provided no additional benefit beyond that provided by the shelter. However, lobsters were able to find shelter significantly faster when conspecific residents were already present in a den. This ‘guide effect’ benefits the shelter-seeking individual by reducing the time of exposure and associated predation risk. Habitat or risk assessment based solely on the presence of conspecifics may be a critical first step in the evolution of more complex social behaviours.

Octopuses influence den selection by juvenile Caribbean spiny lobster

Octopuses are notorious predators of crustaceans, yet knowledge of their interactions with lobsters is largely anecdotal. Whether by preying on juvenile lobsters or by competing with them for dens or bivalve prey, octopuses should influence the den selection and therefore spatial distribution of lobsters. Lobsters are chemosensitive, so if the interaction is strong, they may respond to chemical cues produced by octopuses and avoid dens or areas where octopuses dwell. In mesocosms, juvenile Caribbean spiny lobsters (Panulirus argus) avoided dens emanating octopus chemical signals. Field manipulations of artificial dens at several spatial scales (<0.1 m to 10 m) showed that the distribution of lobsters was significantly influenced by the proximity of octopuses. Lobsters were significantly less likely to inhabit dens within 2 m of an octopus den, but this strong negative effect disappeared when dens were 10 m apart.

Influence of conspecifics on the ontogenetic habitat shift of juvenile Caribbean spiny lobsters

Werner and Gilliam’s (1984) model predicts that size-specific rates of growth and mortality determine the size at transition for animals with an ontogenetic habitat shift (OHS). Although animals are unlikely to calculate mortality rate, they often respond to changes in predation risk. For many social species, an individual’s risk of predation is reduced by conspecific aggregation. We hypothesize that individuals in groups respond to this reduction of predation risk and should shift habitats at a smaller size than solitary individuals. We tested this hypothesis by altering food availability, predation risk and conspecific presence for newly settled spiny lobsters in mesocosms. Juvenile Caribbean spiny lobsters, Panulirus argus, undergo an ontogenetic habitat shift from algal dwelling to crevice sheltering concomitant with aggregation in crevices. We found that juveniles raised with low food availability and low predation risk underwent transition at a smaller size. We also found that juveniles raised with conspecifics underwent transition at a smaller size than did solitary lobsters under the same conditions. Our results suggest that the ontogenetic habitat shift of algal-phase lobsters is accelerated when food is scarce, predation risk is low, and conspecifics are present. In the absence of conspecifics, algal lobsters wait until they are larger to change from algal dwelling to crevice sheltering. This result suggests that ontogenetic habitat shifts for gregarious animals are influenced by the proximity of conspecifics.

Effects of artificial shelters (Casitas) on the abundance and biomass of juvenile spiny lobsters Panulirus argus in a habitat-limited tropical reef lagoon

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 221:221-232 (2001) - doi:10.3354/meps221221 Effects of artificial shelters (Casitas) on the abundance and biomass of juvenile spiny lobsters Panulirus argus in a habitat-limited tropical reef lagoon Patricia Briones-Fourzán*, Enrique Lozano-Álvarez Universidad Nacional Autónoma de México, Instituto de Ciencias del Mar y Limnología, Unidad Académica Puerto Morelos, PO Box 1152 Cancún, Quintana Roo 77500, Mexico *E-mail: briones@mar.icmyl.unam.mx ABSTRACT: ŒCasitas¹ are artificial habitats that mimic large crevice-type shelters sought by juvenile Caribbean spiny lobsters Panulirus argus. Despite the widespread use of casitas for lobster fishing in the Caribbean, the ecological performance of casitas is not yet fully understood. We examined the mode of operation of casitas in a habitat-limited population of juvenile P. argus in the reef lagoon at Puerto Morelos, Mexico. The density of juveniles in the reef lagoon was estimated with transects as 11 ha-1. After the transect surveys, a year-long baseline study on the lobster population, consisting of 13 visual censuses, was conducted at 9 fixed sites, each of area 100 x 100 m (1 ha). All lobsters were juveniles (10.7 to 56.5 mm carapace length, CL), and only 12% measured >35 mm CL. No movement of tagged lobsters was recorded among sites. Overall density in the 9 sites was 5.0 ha-1, but density varied widely in space and time. Two groups of sites were evident: a group of 5 sites with virtually no lobsters (NL sites), and a group of 4 sites with lobsters (WL sites). Lobster density was related to the abundance and size of natural shelters in each site. Casitas were deployed in 2 of the 4 WL and 3 of the 5 NL sites (treatment sites), and further bimonthly censuses were conducted in all sites for an additional year. Despite temporal variations, lobster density in both WL and NL treatment sites increased significantly compared to control sites and to their respective baseline values. The mean size of lobsters and the biomass of all lobsters became gradually larger in treatment sites compared to control sites and to the baseline study, but both mean size and biomass fluctuated in time. These results support the hypothesis that artificial habitats increase the abundance and biomass of lobsters in habitat-limited environments, and the notion of an attraction-production continuum effect of casitas on lobsters. KEY WORDS: Artificial habitats · Casitas · Spiny lobsters · Panulirus argus · Habitat limitation · Attraction-production · Mexican Caribbean Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 221. Online publication date: October 18, 2001 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2001 Inter-Research.

The Use of Coded Microwire Tags in Mark-Recapture Studies of Juvenile Caribbean Spiny Lobster, Panulirus Argus

The Use of Coded Microwire Tags in Mark-Recapture Studies of Juvenile Caribbean Spiny Lobster, Panulirus Argus