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The Caribbean spiny lobster Panulirus argus, a long-lived decapod crustacean, is fished throughout its geographical range and generates close to 1 billion US dollars annually. Fisheries across this range are fully- or over-exploited, spurring management strategies such as closed seasons and minimum size limitations. The objective of this study was to determine the minimum legal size and appropriate closed season for the lobster population of Saint Kitts and Nevis by assessing and comparing the functional, physiological and morphological determinants of sexual maturity. Such a comparison has never been attempted for this species. Females did not reach functional maturity until 87.8 mm carapace length (CL) based on the presence of a spermatophore and eggs, but reached morphological maturity based on the presence of ovigerous setae at 72.5 mm CL. Physiological maturity was intermediate at 82.8 mm CL. Determinants of functional maturity overestimate the size at sexual maturity, while the presence of ovigerous setae underestimates it. The gonadosomatic index, a reliable method of assessing physiological maturity in female P. argus, can be used to monitor changes in reproductive activity in both males and females. Gross assessment of the ovary may be used to determine size at physiological maturity, and functional maturity can be used to calculate peak periods of reproduction. The peak physiological and functional maturity for P. argus occurs from March to May. As a result, we propose a closed season from March to June and suggest assessment of reproductive dynamics in order to determine minimum legal size for harvesting P. argus.

The Nudiviridae are a family of large double-stranded DNA viruses that infects the cells of the gut in invertebrates, including insects and crustaceans. The phylogenetic range of the family has recently been enhanced via the description of viruses infecting penaeid shrimp, crangonid shrimp, homarid lobsters and portunid crabs. Here we extend this by presenting the genome of another nudivirus infecting the amphipod Dikerogammarus haemobaphes. The virus, which infects cells of the host hepatopancreas, has a circular genome of 119,754 bp in length, and encodes a predicted 106 open reading frames. This novel virus encodes all the conserved nudiviral genes (sharing 57 gene homologues with other crustacean-infecting nudiviruses) but appears to lack the p6.9 gene. Phylogenetic analysis revealed that this virus branches before the other crustacean-infecting nudiviruses and shares low levels of gene/protein similarity to the Gammanudivirus genus. Comparison of gene synteny from known crustacean-infecting nudiviruses reveals conservation between Homarus gammarus nudivirus and Penaeus monodon nudivirus; however, three genomic rearrangements in this novel amphipod virus appear to break the gene synteny between this and the ones infecting lobsters and penaeid shrimp. We explore the evolutionary history and systematics of this novel virus, suggesting that it be included in the novel Epsilonnudivirus genus (Nudiviridae).

Among the many Callinectes spp. across the western Atlantic, the blue crab C. sapidus has the broadest latitudinal distribution, encompassing both tropical and temperate climates. Its life history varies latitudinally, from extended overwintering at high latitudes to year-round activity in tropical locations. Callinectes sapidus reovirus 1 (CsRV1) is a pathogenic virus first described in North Atlantic C. sapidus and has recently been detected in southern Brazil. Little information exists about CsRV1 prevalence at intervening latitudes or in overwintering blue crabs. Using a quantitative reverse transcription PCR (RT-qPCR) method, this study investigated CsRV1 prevalence in C. sapidus across latitudinal differences in temperature and crab life history, as well as in additional Callinectes spp. and within overwintering C. sapidus. CsRV1 prevalence in C. sapidus was significantly correlated with high water temperature and blue crab winter dormancy. Prevalence of CsRV1 in C. sapidus on the mid-Atlantic coast was significantly lower in winter than in summer. CsRV1 infections were not detected in other Callinectes spp. These findings revealed that CsRV1 is present in C. sapidus across their range, but not in other Callinectes species, with prevalence associated with temperature and host life history. Such information helps us to better understand the underlying mechanisms that drive marine virus dynamics under changing environmental conditions.

Understanding population genetic structure can help us to infer dispersal patterns, predict population resilience and design effective management strategies. For sessile species with limited dispersal, this is especially pertinent because genetic diversity and connectivity are key aspects of their resilience to environmental stressors. Here, we describe the population structure of Ircinia campana, a common Caribbean sponge subject to mass mortalities and disease. Microsatellites were used to genotype 440 individuals from 19 sites throughout the Greater Caribbean. We found strong genetic structure across the region, and significant isolation by distance across the Lesser Antilles, highlighting the influence of limited larval dispersal. We also observed spatial genetic structure patterns congruent with oceanography. This includes evidence of connectivity between sponges in the Florida Keys and the southeast coast of the United States (>700 km away) where the oceanographic environment is dominated by the strong Florida Current. Conversely, the population in southern Belize was strongly differentiated from all other sites, consistent with the presence of dispersal-limiting oceanographic features, including the Gulf of Honduras gyre. At smaller spatial scales (

For more than 100 years, the Florida Keys (USA) have supported a commercial sponge fishery but there is little information about the small artisanal fishery that now exists, which is nonetheless controversial because of concerns about the ecological consequences of sponge harvest. We estimated the harvest of commercial sponges and bycatch (sublegal or non-commercial species), as well as the mortality, growth, and reproduction of commercial sponge species. In heavily fished areas, ∼33% of the legal-sized sponges, ∼3% of the sublegal sponges, and virtually none of the non-commercial species were harvested. Approximately 40% of our study area was never fished during the four month long peak in the fishing season. Self-reporting of harvest by fishers who participated in our study closely matched our fishery-independent estimates. Natural mortality of sublegal-sized sponges was ∼7% of the population/yr, with little difference among species. Discarded “roller” sponges grew at rates comparable to attached sponges and many reattached to the seafloor within 18 mos, although rates of reattachment varied among species. Growth also differed among species and sampling periods (mean = 3 cm dia/yr), and reproductive effort was positively related to sponge size in some species, but not others. Given the careful targeting of commercial sponge species and sizes by fishers and the small fraction of the sponge community that is commercially valuable, harvest is estimated to have minimal impact on the diverse assemblage of sponges in the region.

Genetic tools can have a key role in informing conservation management of declining populations. Genetic diversity is an important determinant of population fitness and resilience, and can require careful management to ensure sufficient variation is present. In addition, population genetics data reveal patterns of connectivity and gene flow between locations, enabling mangers to predict recovery and resilience, identify areas of local adaptation, and generate restoration plans. Here, we demonstrate a conservation genetics approach to inform restoration and management of the loggerhead sponge (Spheciospongia vesparium) in the Florida Keys, USA. This species is a dominant, habitat-forming component of marine ecosystems in the Caribbean region, but in Florida has suffered numerous mass mortality events. We developed microsatellite markers and used them to genotype sponges from 14 locations in Florida and a site each in The Bahamas, Belize and Barbuda. We found that genetic diversity levels were similar across all sites, but inbreeding and bottleneck signatures were present in Florida. Populations are highly structured at the regional scale, whilst within Florida connectivity is present in a weak isolation by distance pattern, coupled with chaotic genetic patchiness. Evidence of a weak barrier to gene flow was found in Florida among sites situated on opposite sides of the islands in the Middle Keys. Loggerhead sponge populations in Florida are vulnerable in the face of mass mortalities due to low connectivity with other areas in the region, as well as distance-limited and unpredictable local connectivity patterns. However, our discovery of Florida’s high genetic diversity increases hope for resilience to future perturbations. These results provide valuable insight for sponge restoration practice in Florida.

Florida Bay is home to a network of shallow mud-banks which act as barriers to circulation creating small basins that are often subject to extremes in temperature and salinity. Florida bay is also important juvenile habitat for the Caribbean spiny lobster Panulirus argus. While our understanding of the effect of environmental changes on the survival, growth, and movement of spiny lobsters is growing, the effect on their chemosensory abilities has not yet been investigated. Lobsters rely heavily on chemical cues for many biological and ecological activities, and here we report on the effect of extreme environmental events in temperature (32 °C), salinity (45ppt), and pH (7.65 pH) on social behavior and sheltering preference in P. argus. Under normal conditions, chemical cues from conspecifics are used by spiny lobsters to identify suitable shelter and cues from stone crabs and diseased individuals are used to determine shelters to be avoided. In all altered conditions, lobsters lost the ability to aggregate with conspecifics and avoid stone crabs and diseased conspecifics. Thus, seasonal extreme events, and potentially future climate change conditions, alter the chemosensory-driven behavior of P. argus and may result in decreased survivorship due to impaired shelter selection or other behaviors.

Interspecific competition is assumed to have a strong influence on the population dynamics of competing species, but is not easily demonstrated for mobile species in the wild. In the Florida Keys (USA), anecdotal observations have long pointed to an inverse relationship in abundance of two large decapod crustaceans found co-occurring in hard-bottom habitat, the stone crab Menippe mercenaria and the Caribbean spiny lobster Panulirus argus. We used them to explicitly test whether competition for a renewable resource (shelter) can drive the abundance and distribution of the inferior competitor. We first explored this relationship in shelter competition mesocosm experiments to determine the competitively dominant species. Results showed that stone crabs are clearly the dominant competitors regardless of the number of lobsters present, the presence of co-sheltering species such as the spider crab, Damithrax spinosissimus, or the order of introduction of competitors into the mesocosm. We also found that lobsters use chemical cues from stone crabs to detect and avoid them. We then tested the ramifications of this competitive dominance in the field by manipulating stone crab abundance and then tracking the abundance and distribution of spiny lobsters through time. Increased stone crab abundance immediately resulted in decreased lobster abundance and increased aggregation. The opposite occurred on sites where stone crabs were removed. When we stopped removing stone crabs from these sites, they soon returned and lobster abundance decreased. This study explicitly demonstrated that interspecific competition can drive population dynamics between these species, and ultimately, community composition in these shallow water habitats.

© 2016 Springer-Verlag Berlin Heidelberg Connectivity, the exchange of individuals among locations, is a fundamental ecological process that explains how otherwise disparate populations interact. For most marine organisms, dispersal occurs primarily during a pelagic larval phase that connects populations. We paired population structure from comprehensive genetic sampling and biophysical larval transport modeling to describe how spiny lobster (Panulirus argus) population differentiation is related to biological oceanography. A total of 581 lobsters were genotyped with 11 microsatellites from ten locations around the greater Caribbean. The overall FST of 0.0016 (P = 0.005) suggested low yet significant levels of structuring among sites. An isolation by geographic distance model did not explain spatial patterns of genetic differentiation in P. argus (P = 0.19; Mantel r = 0.18), whereas a biophysical connectivity model provided a significant explanation of population differentiation (P = 0.04; Mantel r = 0.47). Thus, even for a widely dispersing species, dispersal occurs over a continuum where basin-wide larval retention creates genetic structure. Our study provides a framework for future explorations of wide-scale larval dispersal and marine connectivity by integrating empirical genetic research and probabilistic modeling.

Casitas are artificial shelters used by fishers to aggregate Caribbean spiny lobsters (Panulirus argus) for ease of capture. However, casitas may function as an ecological trap for juvenile lobsters if they are attracted to casitas and their growth or mortality is poorer compared with natural shelters. We hypothesized that juvenile lobsters may be at particular risk if attracted to casitas because they are less able than larger individuals to defend themselves, and do not forage far from shelter. We compared the nutritional condition, relative mortality, and activity of lobsters of various sizes in casitas and natural shelters in adult and juvenile lobster-dominated habitats in the Florida Keys (United States). We found that the ecological effects of casitas are complex and location-dependent. Lobsters collected from casitas and natural shelters did not differ in nutritional condition. However, juvenile lobsters in casitas experienced higher rates of mortality than did individuals in natural shelters; the mortality of large lobsters did not differ between casitas and natural shelters. Thus, casitas only function as ecological traps when deployed in nursery habitats where juvenile lobsters are lured by conspecifics to casitas where their risk of predation is higher. These results highlight the importance of accounting for animal size and location-dependent effects when considering the consequences of habitat modification for fisheries enhancement.

Knowledge of marine host–parasite relationships has been increasing, but little is known about the reproductive strategies of the parasites. Theoretically, parasitic crustaceans inhabiting relatively small and scarce hosts should be monogamous. Parasites are also expected to exhibit higher reproductive performance (RP) than their free-living relatives, a strategy thought to have evolved to increase host-to-host transmission, or to be the outcome of living in a ‘stable, nutrient-rich environment’. Here, the parasitic isopod Parabopyrella lata and its shrimp host Lysmata boggessi were used to test for monogamy and augmented RP, and to examine whether or not P. lata castrates its host. Prevalence, population distribution, and reproductive performance were examined in P. lata over 1 year (2012–2013) off Homosassa Springs, Florida USA (28.8037° N, 82.5761° W). Prevalence of P. lata on L. boggessi was greater during the warmer months of the year and infested shrimps were almost exclusively males. P. lata lives in male–female pairs within the gill chamber of infested shrimps more frequently than expected by chance alone. The sizes of paired males and females were tightly and positively correlated with each other and with host size. Average fecundity (3660 ± 1146 eggs female−1) and reproductive output (61 ± 19%) in P. lata, as with other bopyrid parasites, was much greater than those reported for free-living isopods. This evidence supports the hypotheses that parasites such as P. lata are adapted to be monogamous, display augmented RP, and reproductively castrate their host.

The PaV1 virus infects spiny lobsters (Panulirus argus) throughout most of the Caribbean, where its prevalence in adult lobsters can reach 17% and where it poses a significant risk of mortality for juveniles. Recent studies indicate that vertical transmission of the virus is unlikely and PaV1 has not been identified in the phyllosoma larval stages. Yet, the pathogen appears subclinically in post-larvae collected near the coast, suggesting that lobster post-larvae may harbour the virus and perhaps have aided in the dispersal of the pathogen. Laboratory and field experiments also confirm the waterborne transmission of the virus to post-larval and early benthic juvenile stages, but its viability in the water column may be limited to a few days. Here, we coupled Lagrangian modelling with a flexible matrix model of waterborne and post-larval-based pathogen dispersal in the Caribbean to investigate how a large area with complex hydrology influences the theoretical spread of disease. Our results indicate that if the virus is waterborne and only viable for a few days, then it is unlikely to impact both the Eastern and Northwestern Caribbean, which are separated by dispersal barriers. However, if PaV1 can be transported between locations by infected post-larvae, then the entire Caribbean becomes linked by pathogen dispersal with higher viral prevalence in the North. We identify possible regions from which pathogens are most likely to spread, and highlight Caribbean locations that function as dispersal “gateways” that could facilitate the rapid spread of pathogens into otherwise isolated areas.

Marine protected areas (MPAs) are an important ecosystem-based management approach to help improve the sustainability of the spiny lobster fishery (Panulirus argus), but information is lacking concerning levels of lobster population connectivity among MPAs. Given their prolonged (~6 months) pelagic larval duration, population connectivity must be considered in any spatial management plan for P. argus. We used genetic techniques to uncover spatial patterns of connectivity among MPAs along the Mesoamerican Barrier Reef (MBRS) of Central America. We hypothesized that connectivity would be greater and genetic differentiation diminished among lobster populations within MPAs in the southern MBRS, which is dominated by a retentive oceanographic environment, as compared to MPAs in the more advective environment further north. We found that levels of connectivity are high among spiny lobster populations residing in MPAs in Central America, although overall F ST was low (F ST = 0.00013) but significant (P = 0.037). MPAs in the northern MBRS contained significantly more individuals that were genetically determined outliers or migrants than southern MPAs (P = 0.008, R 2 = 0.61), which may have contributed to the higher levels of genetic differentiation observed in northern MPAs. Direct genetic testing of larvae and adults will be required to confirm this hypothesis. The high level of connectivity among MPAs provides additional evidence of the importance of international cooperation in the management of Caribbean lobster fisheries. However, uncertainty regarding the ecological and physical drivers of genetic differentiation in Northern MPAs implies that managers should hedge against uncertainty.

The pathogenic virus Panulirus argus virus 1 (PaV1) was first discovered in Caribbean spiny lobsters Panulirus argus from the Florida Keys (USA) in 1999 and has since been reported in Belize, Mexico, and Cuba; its distribution in the wider Caribbean is unknown. We col- lected tissue samples from adult spiny lobsters from 30 locations in 14 countries bordering the Caribbean Sea and used molecular diagnostics to assay for the presence of PaV1. PaV1 occurred primarily in the northern areas of the Caribbean, where its prevalence was highest. The virus was not found in lobsters from the southeastern Caribbean, and its prevalence was lowest in the south- western Caribbean. DNA sequence analysis was performed on a fragment of the viral DNA to examine the genetic diversity of PaV1 on a Caribbean-wide scale. Sequence variation in the viral DNA fragment was high, with 61 unique alleles identified from 9 areas. The sharing of viral alleles in lobsters from distant locations supports the hypothesis of a strong genetic connectivity among lobsters within the Caribbean, and further supports the hypothesis that postlarvae infected with PaV1 may serve to disperse the virus over long distances.

Pathogens can influence the behaviors of their hosts, including avoidance by healthy individuals. However, the spatial structuring consequences of these behaviors are often unknown, especially in the marine environment. The Caribbean spiny lobster Panulirus argus (Latreille, 1804) avoids sheltering with conspecifics infected with P. argus virus 1 (PaV1). We sought to deter- mine the behavioral cue and if this behavior alters population spatial structure in the wild. We used a series of laboratory Y-maze experiments to determine the mechanism of detection and also employed artificial shelter arrays placed in different flow conditions in the field to determine the effect of diseased lobster aversion on healthy lobster spatial dynamics. Results showed that avoid- ance is driven by the chemoreception of cues based in the urine. The chemical cue alone was as effective as having a diseased lobster present and visible. The presence of single PaV1-infected lobsters altered the small-scale spatial structure of wild populations, especially under low flow regimes, via redistribution of neighboring individuals. In shelter-limited environments, disease avoidance has the potential to increase juvenile mortality, as nearby conspecifics are displaced from dens and exposed to a higher risk of predation.

The Caribbean King crab Mithrax spinosissimus is the largest brachyuran found in the western Atlantic and it supports subsistence and small commercial fisheries throughout the Caribbean and Gulf of Mexico. Because of its short larval duration and rapid growth, M. spinosissimus is considered a good candidate for aquaculture. Our study documents for the first time the size at sexual maturity, sexual dimorphism, and allometric growth relative to carapace width for certain secondary sexual characters in male and female M. spinosissimus from the Florida Keys, Florida. Using principal component analysis, K-means cluster analysis, and discriminant analysis, we identified 2 major growth phases in the postlarval benthic life of this species (juvenile or prepubertal and adult or pubertal). The typical growth pattern for majoid crabs includes a third, intermediate growth phase that appears absent in M. spinosissimus. The major cheliped of males was larger than that of females and exhibited positive allometric growth to maturity, after which the level of allometry decreased. In females, both chelipeds exhibited positive allometry throughout ontogeny. Abdominal width was negatively allometric throughout ontogeny in males, whereas in females the abdomen exhibited positive allometric growth until reproductive maturity, at which point it became isometric. Logistic regression indicated that the carapace width at first maturity was 45.2 mm in males and 69.7 mm in females. This new information should be taken into account when assessing stocks and setting harvest regulations if this fishery is to be managed sustainably.

Lobsters are prized by commercial and recreational fishermen worldwide, and their populations are therefore buffeted by fishery practices. But lobsters also remain integral members of their benthic communities where predator-prey relationships, competitive interactions, and host-pathogen dynamics push and pull at their population dynamics. Although lobsters have few reported pathogens and parasites relative to other decapod crustaceans, the rise of diseases with consequences for lobster fisheries and aquaculture has spotlighted the importance of disease for lobster biology, population dynamics and ecology. Researchers, managers, and fishers thus increasingly recognize the need to understand lobster pathogens and parasites so they can be managed proactively and their impacts minimized where possible. At the 2011 International Conference and Workshop on Lobster Biology and Management a special session on lobster diseases was convened and this special issue of Diseases of Aquatic Organisms highlights those proceedings with a suite of articles focused on diseases discussed during that session.

Studies of fish ecology are enhanced by precise and accurate knowledge of survival, which can be estimated from capture-recapture/resighting based survival probabilities. We conducted a cost-benefit analysis of resighting by an array of 11 autonomous PIT tag antennae and recapture by seine netting, and compared the effectiveness of the two methods for recapturing/resighting marked fish in an estuarine environment. During three separate marking periods, we marked a total of 2109 fish with PIT tags, recapturing 106 by seine (5.0%) and resighting 1700 by antennae (80.6%). Antennae resulted in precise monthly survival estimates while seine netting did not, but antennae did not collect ancillary data (e.g., growth) and their use was limited to areas where fish used constricted passes

Panulirus argus virus 1 (PaV1) is an unclassified, pathogenic virus first discovered in Caribbean spiny lobsters Panulirus argus from the Florida Keys, USA, and has since been con- firmed in lobsters in other parts of the Caribbean. Several studies have examined the prevalence, pathogenicity, and population dynamics of the pathogen in the lobster host, but little is known about the genetic diversity of the virus. We analyzed a fragment of viral DNA from lobsters col- lected in the Florida Keys, which provided the first insight into the genetic diversity of PaV1. The variation in viral sequences, both within and between individual lobsters, indicates that lobsters can be infected with multiple viral strains. Laboratory experiments in which uninfected lobsters were serially exposed to lobsters inoculated with PaV1 implied that rapid mutation of strains is unlikely and suggest that there may be endemic strains of PaV1. In addition, we discovered PaV1 in P. argus postlarvae (pueruli), suggesting that the virus may disperse through the Caribbean within the long-lived (5 to 7 mo) planktonic phyllosoma larvae — a novel mechanism for dispersal of viruses in the sea.

Caribbean spiny lobster ( Panulirus argus) settle preferentially in macroalgal-covered hard-bottom habitat, but seagrass is more prevalent in Florida (United States) and the Caribbean, so even low settlement of lobsters within seagrass could contribute substantially to recruitment if post-settlement survival and growth were high. We tested the role of seagrass and hard-bottom habitats for P. argus recruitment in three ways. We first explored possible density-dependent regulation of early benthic juvenile lobster survival within cages deployed in seagrass and hard-bottom habitats. Second, we compared settlement and survival of P. argus in both habitats, by comparing the recovery of microwire-tagged early benthic juveniles from patches of seagrass and hard-bottom. Finally, we assessed the relative abundance of juvenile lobsters in each habitat by deploying artificial structures in seagrass sites and compared these data with data from similar deployments of artificial structures in hard-bottom habitat in other years. More early benthic juvenile lobsters were recovered from cages placed in hard-bottom than in seagrass, but mortality of the early benthic life stage was high in both habitats. in regional surveys, the mean number of lobsters recovered from artificial shelters deployed within seagrass was lower than in any year that we sampled hard-bottom, indicating that fewer lobsters reside naturally in seagrass, particularly large juveniles >40 mm carapace length. The greater abundance (and likely survival) of juvenile P. argus that we observed in hard-bottom habitat as opposed to seagrass, combined with previous studies demonstrating that postlarval P. argus are attracted to, settle in, and metamorphose more quickly in red macroalgae, confirm that macroalgae-dominated hard-bottom habitat appears to be the preferred and more optimal nursery for Caribbean spiny lobster.

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. © 2008 Elsevier B.V. All rights reserved.

Spanier, Ehud ... et. al.-- Contribution to the Supplement: Lobsters in a Changing Climate.-- 15 pages, 7 figures, Lobsters are important resources throughout the world's oceans, providing food security, employment, and a trading commodity. Whereas marine biologists generally focus on modern impacts of fisheries, here we explore the deep history of lobster exploitation by prehistorical humans and ancient civilizations, through the first half of the 20th century. Evidence of lobster use comprises midden remains, artwork, artefacts, writings about lobsters, and written sources describing the fishing practices of indigenous peoples. Evidence from archaeological dig sites is potentially biased because lobster shells are relatively thin and easily degraded in most midden soils; in some cases, they may have been used as fertilizer for crops instead of being dumped in middens. Lobsters were a valuable food and economic resource for early coastal peoples, and ancient Greek and Roman Mediterranean civilizations amassed considerable knowledge of their biology and fisheries. Before European contact, lobsters were utilized by indigenous societies in the Americas, southern Africa, Australia, and New Zealand at seemingly sustainable levels, even while other fish and molluscan species may have been overfished. All written records suggest that coastal lobster populations were dense, even in the presence of abundant and large groundfish predators, and that lobsters were much larger than at present. Lobsters gained a reputation as “food for the poor” in 17th and 18th century Europe and parts of North America, but became a fashionable seafood commodity during the mid-19th century. High demand led to intensified fishing effort with improved fishing gear and boats, and advances in preservation and long-distance transport. By the early 20th century, coastal stocks were overfished in many places and average lobster size was significantly reduced. With overfishing came attempts to regulate fisheries, which have varied over time and have met with limited success

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 ornamental trade is a worldwide industry worth >15 billion USD with a problem of rampant product misidentification. Minimizing misidentification is critical in the face of overexploitation of species in the trade. We surveyed the peppermint shrimp ornamental marketplace in the southeastern USA, the most intense market for peppermint shrimps worldwide, to characterize the composition of species in the trade, reveal the extent of misidentification, and describe the population genetics of the true target species. Shrimps were bought from aquarium shops in FL, GA, SC, and NC. We demonstrated, contrary to popular belief (information from dealers), that the most heavily traded species in the market wasLysmata boggessi, an endemic species to the eastern Gulf of Mexico, and notLysmata wurdemanni. Importantly, only when color pattern or genetic markers in conjunction with morphological traits were employed, was it was possible to unequivocally identifyL. boggessias the only species in the trade. The intensity of the market for peppermint shrimps in the USA has led toL. boggessibeing the most traded species worldwide. Misidentification in the shrimp aquarium trade is accidental and involuntary, and is explained by remarkable similarity among congeneric species. Using sequences of the 16S-mt-DNA marker, we found no indication of population genetic structure in the endemicL. boggessiacross 550 km of linear coast. Therefore, this species can be considered genetically homogeneous and a single fished stock. Still, we argue in favor of additional studies using more powerful markers (e.g., SNPs) capable of revealing genetic structure at a finer spatial-scale. Our results will help advance management and conservation policies in this lucrative yet understudied fishery. Future studies of other ornamental fisheries will benefit from using an integrative taxonomic approach, as we demonstrate here.

Management of the few regulated ornamental fisheries relies on inadequate information about the life history of the target species. Herein, we investigated the reproductive biology of the most heavily traded marine invertebrate in the western Atlantic; the blue-legged hermit crabClibanarius tricolor. We report on density, individual-level, and population-level reproductive parameters in 14 populations spanning the Florida Keys. In C. tricolor, abundance, population-level, and individual-level reproductive parameters exhibited substantial small-scale spatial variation in the Florida Keys. For instance, the proportion of brooding females varied between 10–94% across localities. In females, average (±SD) fecundity varied between 184 (±54) and 614 (±301) embryos crab-1 across populations. Fecundity usually increases with female body size in hermit crabs. However, we found no effect of female body size on fecundity in three of the populations. Altogether, our observations suggest that C. tricolor may fit a source-sink metapopulation dynamic in the Florida Keys with low reproductive intensity and absence of a parental body size—fecundity relationship resulting in net reproductive loses at some localities. We argue in favor of additional studies describing population dynamics and other aspects of the natural history of C. tricolor (e.g., development type, larval duration) to reveal ‘source’ populations, capable of exporting larvae to nearby populations. Our observations imply that future studies aimed at assessing standing stocks or describing other aspects of the life history of this hermit crab need to focus on multiple localities simultaneously. This and future studies on the reproductive biology of this species will form the baseline for models aimed at assessing the stock condition and sustainability of this heavily harvested crustacean.

Decapod crustaceans (i.e., lobsters, crabs, and shrimps) are all subject to disease, both in the wild and in culture. No life stage appears to be immune to some form of pathogen or parasite. However, juveniles appear to be the targets of some of the most pervasive and consequential diseases. It is therefore surprising, given the enormous economic value of adult decapods, that we know so little about the effects of pathogens on their vulnerable life stage. Here I review the significant diseases reported for juvenile decapods that support fisheries and aquaculture, and highlight research that demonstrates the advantage of incorporating juveniles and ecology in studies of disease.

Sociality has evolved in a wide range of animal taxa but infectious diseases spread rapidly in populations of aggregated individuals, potentially negating the advantages of their social interactions. To disengage from the coevolutionary struggle with pathogens, some hosts have evolved various forms of "behavioral immunity"; yet, the effectiveness of such behaviors in controlling epizootics in the wild is untested. Here we show how one form of behavioral immunity (i.e., the aversion of diseased conspecifics) practiced by Caribbean spiny lobsters (Panulirus argus) when subject to the socially transmitted PaV1 virus, appears to have prevented an epizootic over a large seascape. We capitalized on a "natural experiment" in which a die-off of sponges in the Florida Keys (USA) resulted in a loss of shelters for juvenile lobsters over a ~2500km2 region. Lobsters were thus concentrated in the few remaining shelters, presumably increasing their exposure to the contagious virus. Despite this spatial reorganization of the population, viral prevalence in lobsters remained unchanged after the sponge die-off and for years thereafter. A field experiment in which we introduced either a healthy or PaV1-infected lobster into lobster aggregations in natural dens confirmed that spiny lobsters practice behavioral immunity. Healthy lobsters vacated dens occupied by PaV1-infected lobsters despite the scarcity of alternative shelters and the higher risk of predation they faced when searching for a new den. Simulations from a spatially-explicit, individual-based model confirmed our empirical results, demonstrating the efficacy of behavioral immunity in preventing epizootics in this system.

Transmissible pathogens are the bane of social animals, so they have evolved behaviours to decrease the probability of infection. There is no record, however, of social animals avoiding diseased individuals of their own species in the wild. Here we show how healthy, normally gregarious Caribbean spiny lobsters (Panulirus argus) avoid conspecifics that are infected with a lethal virus. Early detection and avoidance of infected, though not yet infectious, individuals by healthy lobsters confers a selective advantage and highlights the importance of host behaviour in disease transmission among natural populations.