Spiny Lobster Panulirus Argus Research Articles

P.1.g.086 - Pharmacological investigation of alpha7 nAChR and mGluR2 in human pluripotent stem cell derived dentate gyrus neurons: implications for schizophrenia

We have studied the effects of groups I, II, and III metabotropic glutamate receptor (mGluR) agonists and antagonists on pyloric activity in the stomatogastric ganglion (STG) of the Caribbean spiny lobster Panulirus argus. We have found that agonists for all three groups of mGluRs modify the pyloric output. The group I agonist, l-quisqualic acid (l-QA), activated the pyloric central pattern generator (CPG). When the pyloric rhythm was partially suppressed by sucrose-block of input fibers in the stomatogastric nerve (stn), l-QA accelerated the rhythmic activity. In addition, the number of spike discharges was increased in pyloric motoneurons: pyloric (PY), and lateral pyloric (LP). In completely blocked preparations, a slow pyloric rhythm was initiated by l-QA. Groups II and III agonists exerted an inhibitory effect on pyloric activity. The group II agonist, (2S,1′S,2′S)-2-(Carboxycyclopropyl)glycine (L-CCG-I), decreased both the frequency of the pyloric rhythm and the number of spike discharges in the motoneurons: ventricular dilator (VD), PY, and LP. The effects of L-CCG-I were dose-dependent. The group III agonist, l-(+)-2-Amino-4-phosphonobutyric acid (l-AP4), slightly decreased the frequency of the pyloric rhythm and suppressed spike discharges in the VD neuron. All effects of mGluR agonists were reversible. The effect of l-QA was blocked by the broad spectrum mGluR antagonist (S)-Methyl-4-carboxyphenylglycine (MCPG). The inhibitory effect of L-CCG-I was prevented by MCPG and by the group II/III mGluR antagonist (RS)-α-Methyl-4-phosphonophenylglycine (MPPG), and was partially blocked by the group II mGluR antagonist (RS)-1-amino-5-phosphonoindan-1-carboxylic acid (APICA). The inhibitory effect of l-AP4 was blocked by MPPG and partially blocked by APICA.

Active parental care, reproductive performance, and a novel egg predator affecting reproductive investment in the Caribbean spiny lobster Panulirus argus

We used the Caribbean spiny lobster Panulirus argus, one of the largest brooding invertebrates in the Western Atlantic, to test for the presence/absence of active parental care and to explore reproductive performance in large brooding marine organisms. Given [i] the compact and large embryo masses produced by P. argus, [ii] the expected disproportional increase in brooding costs with increasing embryo mass size, and [iii] the theoretical allometry of egg production with increasing body size, we predicted that parental females in this large species will engage in active brood care. We also predicted that larger broods from larger lobsters should suffer higher mortality and brood loss than smaller broods from smaller lobsters if parental care was minimal or absent. Lastly, we expected smaller females to allocate disproportionably more resources to egg production than larger females in the case of minimal parental care. Females brooding early and late embryos were collected from different reefs in the Florida Keys Reef tract, transported to the laboratory, and maintained in separate aquaria to describe and quantify active parental care during day and night. A second set of females was retrieved from the field and their carapace length, fecundity, egg size, reproductive output and presence/absence of brood-dwelling pathogens was recorded. Laboratory experiments demonstrated that brooding females of P. argus engaged in active brood care. Females likely use some of the observed behaviors (e.g., abdominal flapping, pleopod beating) to provide oxygen to their brood mass. In Panulirus argus, females did not suffer brood loss during embryo development. Also, reproductive output increased more than proportionally with a unit increase in lobster body weight. Our results agree with the view that large brooding marine invertebrates can produce large embryo masses if they engage in active parental care and that the latter behavior greatly diminishes reproductive performance costs associated with producing large embryo masses. Lastly, we report on a nemertean worm that, we show, negatively impacts female reproductive performance.

Molecular, Biochemical, and Dietary Regulation Features of α-Amylase in a Carnivorous Crustacean, the Spiny Lobster Panulirus argus.

Alpha-amylases are ubiquitously distributed throughout microbials, plants and animals. It is widely accepted that omnivorous crustaceans have higher α-amylase activity and number of isoforms than carnivorous, but contradictory results have been obtained in some species, and carnivorous crustaceans have been less studied. In addition, the physiological meaning of α-amylase polymorphism in crustaceans is not well understood. In this work we studied α-amylase in a carnivorous lobster at the gene, transcript, and protein levels. It was showed that α-amylase isoenzyme composition (i.e., phenotype) in lobster determines carbohydrate digestion efficiency. Most frequent α-amylase phenotype has the lowest digestion efficiency, suggesting this is a favoured trait. We revealed that gene and intron loss have occurred in lobster α-amylase, thus lobsters express a single 1830 bp cDNA encoding a highly conserved protein with 513 amino acids. This protein gives rise to two isoenzymes in some individuals by glycosylation but not by limited proteolysis. Only the glycosylated isoenzyme could be purified by chromatography, with biochemical features similar to other animal amylases. High carbohydrate content in diet down-regulates α-amylase gene expression in lobster. However, high α-amylase activity occurs in lobster gastric juice irrespective of diet and was proposed to function as an early sensor of the carbohydrate content of diet to regulate further gene expression. We concluded that gene/isoenzyme simplicity, post-translational modifications and low Km, coupled with a tight regulation of gene expression, have arose during evolution of α-amylase in the carnivorous lobster to control excessive carbohydrate digestion in the presence of an active α-amylase.

Variación fenotípica de la langosta espinosa Panulirus argus (Decapoda: Paniluridae) en el Caribe Suroccidental

The spiny lobster Panulirus argus is an important fishery species in the Western Central Atlantic. Changes in the dispersion range through its life cycle and heterogeneous habitats, suggest that P. argus exhibit phenotypic plasticity. However, the morphometric variation of this species is unknown so far, although this information is relevant in evolutionary studies as well as to solve questions of fishery interest. Thus, the aim of this study was to determine whether P. argus exhibit phenotypic variation between sexes, among five geographic origins and three oceanographic conditions of Southwest Caribbean (Colombian archipelago San Andrés, Providencia y Santa Catalina). A total of 193 P. argus adults were submitted to geometric morphometrics using six landmarks that delimit one half of the sternal plate. The differences in sternal plate size were compared with Kruskal-Wallis and Mann-Whitney Tests. The allometric effect was estimated using Multivariate Regression Analysis, the model of allometric slopes was tested by Multivariate analysis of covariance and the sternal plate shape differences was explored using non-parametric comparisons of Euclidian distances and Neighbour Joinnig trees. The results showed that the morphometric variation of sternal plate of this spiny lobster varied according to the gender since the sexual size and shape dimorphisms were significant. In both sexes, the sternal plate shape differed among oceanographic scenarios as it was evidenced by significant differences among Euclidian distances, and the tendency to cluster by North, Centre and South sections of San Andrés archipelago. Additionally, the morphometric variation resulting from phenotypic plasticity to variable ecological contexts may explain the phenotypic differences among genetically similar populations. This information permits to define management units, support the selection of regulatory policies of this fishery and complement the genetic analysis of the species in this Caribbean region.

Landscape Analysis for PaV1 Infection in Lobsters Panulirus argus from the Artisanal Fishery of the Eastern Coast of Yucatan, Mexico

Panulirus argus virus 1 (PaV1) is considered a major threat to spiny lobsters Panulirus argus. In this study Geospatial analysis was used to analyze PaV1 distribution in an artisanal fishery of spiny lobster Panulirus argus population from the north coast of the Yucatan Peninsula. Adult and sub-adult P. argus and seabed coverage data were collected from thirty artisanal fishing sites. Five seabed coverage types were identified: seagrass; sand/seagrass mixture; sand only; coral/sand mixture; and seaweed. No juveniles were examined. Of the 358 collected lobsters, PaV1 was identified in four organisms (three sub-adults and one adult) from two fishing sites (termed A ＆ B), both found in a seagrass coverage area. Overall prevalence was of 1.12%. Prevalence was of 20% (2/10) at one site and of 12.6% (2/16) at the other.

Sex differences in the composition of the natural diet of Panulirus argus (Decapoda: Palinuridae) in the eastern of the Gulf of Batabano, Cuba

The spiny lobster Panulirus argus is one of the most valuable fishery resources in the Caribbean Sea. This is the only species of lobster that has commercial importance in Cuba. This study was aimed to identify the organisms that conform the natural diet for both sexes of P. argus and to determine the importance of each prey in the diet of each sex. A total of 30 stomachs of commercial lobsters (≥ 76mm of carapace length) was analyzed. The identified content was grouping by items and classified for species if it was possible. The total weight of each item was determined and the gravimetric method was applied to estimate the relative weight of the principal diet components. The most frequently consumed prey was also determined. Items with high, middle or low importance were established by the relative importance index (IIR). Similarities between both sexes diet were estimated by similarity index (ISe). Stomachs were extracted of lobsters captured in a fishing zones from eastern of the gulf of Batabano. The predation pressure (P) on the mollusks species found in the stomach content was calculated based on the respective opercula. It was possible to identified 15 feeding entities (12 in females and 14 in the males) being the preferences: crustacean rests (100%), shell rests (80%), vegetable rests (70%), opercula (63%) and mineral rests (53%). Those preference entities were the same between sexes although in the males the foraminifera and the mineral rest were included. The IIR showed crustaceans as a single group of high importance. The gravimetric analysis showed crustaceans as the most consumed prey (62.3% in females and 40% in males). The opercula of Lobatus gigas, Turbo castanea, Fasciolaria tulipa, Nassarius antillarum, Cerithium sp and Tegula fasciata were found. Tegula fasciata showed the highest predation pressure (2.25 in females and 2.14 in males) and together Cerithium sp. they were the most abundant species (60.5% and 33.9% respectively). Respect to the weight of stomach contents the Mann-Whitney test showed no significant difference between females and males. The diet of both sexes of P. argus in the assessed area was similar (ISe=96.75%) and it was constituted mainly of crustaceans and mollusks.

Panulirus argus virus 1 detected in oceanic postlarvae of Caribbean spiny lobster: implications for disease dispersal.

Panulirus argus virus 1 (PaV1), a pathogenic virus that specifically attacks Caribbean spiny lobsters Panulirus argus, was recently detected in newly settled postlarvae of P. argus. As PaV1 appears not to be vertically transmitted, infected postlarvae likely acquire PaV1 from the water, but whether this can occur in oceanic waters where the planktonic larvae (phyllosomata) metamorphose into nektonic postlarvae remains unknown. Late-stage phyllosomata and postlarvae of P. argus were collected at distances of 2 to 100 km from the Caribbean coast of Mexico in 2 oceanographic cruises. Most postlarvae were caught in the upper meter of water, usually along with masses of floating Sargassum algae. A PaV1-PCR assay was used to test 169 phyllosomata (stages VI-X) and 239 postlarvae. All phyllosomata tested negative, but 2 postlarvae, 1 from each cruise, tested positive for PaV1. These postlarvae were collected at 55 and 48 km offshore over depths of 850 and 1800 m, respectively, suggesting that postlarvae can acquire PaV1 in offshore waters. We hypothesize that floating Sargassum may be an environmental reservoir for PaV1. The PaV1 allele (460 pb) found in an infected postlarva was more closely related to PaV1 alleles found in lobsters from Puerto Rico than in lobsters from any other location (including Mexico), suggesting high gene flow and long-distance dispersal of PaV1, consistent with previous studies of high genetic connectivity across the Caribbean.

Central projections of antennular chemosensory and mechanosensory afferents in the brain of the terrestrial hermit crab (Coenobita clypeatus; Coenobitidae, Anomura).

The Coenobitidae (Decapoda, Anomura, Paguroidea) is a taxon of hermit crabs that includes two genera with a fully terrestrial life style as adults. Previous studies have shown that Coenobitidae have evolved a sense of spatial odor localization that is behaviorally highly relevant. Here, we examined the central olfactory pathway of these animals by analyzing central projections of the antennular nerve of Coenobita clypeatus, combining backfilling of the nerve with dextran-coupled dye, Golgi impregnations and three-dimensional reconstruction of the primary olfactory center, the antennular lobe. The principal pattern of putative olfactory sensory afferents in C. clypeatus is in many aspects similar to what have been established for aquatic decapod crustaceans, such as the spiny lobster Panulirus argus. However, there are also obvious differences that may, or may not represent adaptations related to a terrestrial lifestyle. In C. clypeatus, the antennular lobe dominates the deutocerebrum, having more than one thousand allantoid-shaped subunits. We observed two distinct patterns of sensory neuron innervation: putative olfactory afferents from the aesthetascs either supply the cap/subcap region of the subunits or they extend through its full depth. Our data also demonstrate that any one sensory axon can supply input to several subunits. Putative chemosensory (non-aesthetasc) and mechanosensory axons represent a different pathway and innervate the lateral and median antennular neuropils. Hence, we suggest that the chemosensory input in C. clypeatus might be represented via a dual pathway: aesthetascs target the antennular lobe, and bimodal sensilla target the lateral antennular neuropil and median antennular neuropil. The present data is compared to related findings in other decapod crustaceans.

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.

Large-scale oceanic circulation and larval recruitment of the spiny lobster Panulirus argus (Latreille, 1804)

The most important populations of the spiny lobster (Panulirus argus(Latreille, 1804)) in the Atlantic are found in the Caribbean and along the Brazilian coast. Field studies covering the waters off the Cuban archipelago and Brazil have improved our understanding of the importance of oceanic circulation to larval recruitment. South of Cuba, puerulus settlement is intensive in October and November when the coastal reefs (83°W) are impacted by a cyclone-anticyclone pair, suggesting this area is the main source of retention and supply of surviving larvae, thus of self-recruitment. On the continental shelf of Brazil, puerulus settlement takes place throughout the year, but two annual peaks have been identified: one in March-April and one in July-September, when retroflection eddies of the North Brazil Current are more intense and feed into the eastward-flowing North Equatorial Countercurrent. Conceivably, Brazilian spiny lobster larvae are trapped in this oceanic system, leading to self-recruitment. On the continental shelf of Brazil the larval period lasts 6-7 months, depending on the season and spawning date. In the Caribbean the period is reported to be 6-8 months. Information on the relative abundance of early-stage spiny lobster larvae makes it possible to predict patterns of recruitment of pueruli and juveniles and the timing of their life cycle. However, further research on seasonal variations in local currents, current retroflection and ring formation is needed to clarify important aspects of larval transport, puerulus settlement and recruitment.

A holistic view of dietary carbohydrate utilization in lobster: digestion, postprandial nutrient flux, and metabolism.

Crustaceans exhibit a remarkable variation in their feeding habits and food type, but most knowledge on carbohydrate digestion and utilization in this group has come from research on few species. The aim of this study was to make an integrative analysis of dietary carbohydrate utilization in the spiny lobster Panulirus argus. We used complementary methodologies such as different assessments of digestibility, activity measurements of digestive and metabolic enzymes, and post-feeding flux of nutrients and metabolites. Several carbohydrates were well digested by the lobster, but maize starch was less digestible than all other starches studied, and its inclusion in diet affected protein digestibility. Most intense hydrolysis of carbohydrates in the gastric chamber of lobster occurred between 2–6 h after ingestion and afterwards free glucose increased in hemolymph. The inclusion of wheat in diet produced a slow clearance of glucose from the gastric fluid and a gradual increase in hemolymph glucose. More intense hydrolysis of protein in the gastric chamber occurred 6–12 h after ingestion and then amino acids tended to increase in hemolymph. Triglyceride concentration in hemolymph rose earlier in wheat-fed lobsters than in lobsters fed other carbohydrates, but it decreased the most 24 h later. Analyses of metabolite levels and activities of different metabolic enzymes revealed that intermolt lobsters had a low capacity to store and use glycogen, although it was slightly higher in wheat-fed lobsters. Lobsters fed maize and rice diets increased amino acid catabolism, while wheat-fed lobsters exhibited higher utilization of fatty acids. Multivariate analysis confirmed that the type of carbohydrate ingested had a profound effect on overall metabolism. Although we found no evidence of a protein-sparing effect of dietary carbohydrate, differences in the kinetics of their digestion and absorption impacted lobster metabolism determining the fate of other nutrients.

Trypsin isozymes in the lobster Panulirus argus (Latreille, 1804): from molecules to physiology.

Trypsin enzymes have been studied in a wide variety of animal taxa due to their central role in protein digestion as well as in other important physiological and biotechnological processes. Crustacean trypsins exhibit a high number of isoforms. However, while differences in properties of isoenzymes are known to play important roles in regulating different physiological processes, there is little information on this aspect for decapod trypsins. The aim of this review is to integrate recent findings at the molecular level on trypsin enzymes of the spiny lobster Panulirus argus, into higher levels of organization (biochemical, organism) and to interpret those findings in relation to the feeding ecology of these crustaceans. Trypsin in lobster is a polymorphic enzyme, showing isoforms that differ in their biochemical features and catalytic efficiencies. Molecular studies suggest that polymorphism in lobster trypsins may be non-neutral. Trypsin isoenzymes are differentially regulated by dietary proteins, and it seems that some isoenzymes have undergone adaptive evolution coupled with a divergence in expression rate to increase fitness. This review highlights important but poorly studied issues in crustaceans in general, such as the relation among trypsin polymorphism, phenotypic (digestive) flexibility, digestion efficiency, and feeding ecology.

In situ swimming and orientation behavior of spiny lobster (Panulirus argus) postlarvae

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 504:207-219 (2014) - DOI: https://doi.org/10.3354/meps10748 In situ swimming and orientation behavior of spiny lobster (Panulirus argus) postlarvae Andrew S. Kough*, Claire B. Paris, Erica Staaterman Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, Florida 33149, USA *Corresponding author: andrew.kough@gmail.com ABSTRACT: Larval dispersal is common in benthic marine organisms, but the environmental cues guiding the final larval stages to settlement habitat remain largely unknown. Caribbean spiny lobster Panulirus argus spend 5 to 12 mo at sea as pelagic phyllosome larvae before transitioning into rapidly swimming and non-feeding puerulus postlarvae. Spiny lobster postlarvae are specialized to seek settlement habitat, making them an ideal model for studying orientation behavior during the transition to benthic environments. We observed the swimming orientation of P. argus in the open ocean during all hours of the day and across tidal phases using a circular behavioral arena deployed at sea. Contrary to laboratory observations of only nocturnal activity, swimming and orientation occurred during both the day and the night in open waters ca. 6 to 8 km offshore in the Florida Straits. Individual postlarvae swam directionally with similar accuracy in all hours. The mean orientation direction was significantly different with tidal phase. Postlarvae oriented to the southeast (163.5°) during flood tide, and to the southwest during ebb flow (225.1°), placing them on a shoreward trajectory. Postlarval behavior was circatidal, and during ebb tide, innate swimming behavior beneficial to finding settlement habitat was triggered. Postlarvae also oriented relative to the wind, potentially using the sea breeze to orient towards the coast. A change in behavior tied to ubiquitous coastal signals is a strategy likely used by other pelagic larvae searching for a benthic home. KEY WORDS: Spiny lobster · Orientation · Postlarva · Nocturnal · Tidal · Dispersal · Settlement Full text in pdf format PreviousNextCite this article as: Kough AS, Paris CB, Staaterman E (2014) In situ swimming and orientation behavior of spiny lobster (Panulirus argus) postlarvae. Mar Ecol Prog Ser 504:207-219. https://doi.org/10.3354/meps10748 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 504. Online publication date: May 14, 2014 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2014 Inter-Research.

Reproductive potential and stock recruitment of the Caribbean and Brazilian metapopulations of the spiny lobster, Panulirus argus (Latreille, 1804)

The spiny lobsterPanulirus argus(Latreille, 1804) is the most important commercial fishing resource in the western central Atlantic and Brazil. Field studies covering the waters off southwestern Cuba and northern Brazil have improved our understanding of the variations in the reproductive potential (number of eggs), stock recruitment and reproductive efficiency of spiny lobsters according to location, depth and size class. Using the spawner-recruitment model, the reproductive potential index was correlated with the index of subsequent recruitment based on field sampling. Spiny lobster habitats in deeper waters need special attention in order to protect the species from overfishing of the recruitment. Considering the longevity and absence of reproductive senility in spiny lobsters, management strategies should ideally include the creation of spawner sanctuaries (marine protected areas) capable of restoring and maintaining the biomass of the spawning stock and the establishment of a maximum catch size of 135 mm (CL) for both sexes along the entire Brazilian coast. Based on our findings, we propose to establish spiny lobster sanctuaries (50-100 m) on the continental shelf off northern Brazil, from Amapá (5°25′N 51°0′W) to the western reaches of the coast of Pará (1°11′N 46°27′W, 0°42′N 46°45′W), covering a total surface area of 64 230 km2.

Lobster Trap Debris in the Florida Keys National Marine Sanctuary: Distribution, Abundance, Density, and Patterns of Accumulation

AbstractThe fishery for spiny lobster Panulirus argus in the Florida Keys National Marine Sanctuary is well chronicled, but little information is available on the prevalence of lost or abandoned lobster traps. In 2007, towed‐diver surveys were used to identify and count pieces of trap debris and any other marine debris encountered. Trap debris density (debris incidences/ha) in historic trap‐use zones and in representative benthic habitats was estimated. Trap debris was not proportionally distributed with fishing effort. Coral habitats had the greatest density of trap debris despite trap fishers' reported avoidance of coral reefs while fishing. The accumulation of trap debris on coral emphasizes the role of wind in redistributing traps and trap debris in the sanctuary. We estimated that 85,548±23,387 (mean±SD) ghost traps and 1,056,127±124,919 nonfishing traps or remnants of traps were present in the study area. Given the large numbers of traps in the fishery and the lack of effective measures for managing and controlling the loss of gear, the generation of trap debris will likely continue in proportion to the number of traps deployed in the fishery. Focused removal of submerged trap debris from especially vulnerable habitats such as reefs and hardbottom, where trap debris density is high, would mitigate key habitat issues but would not address ghost fishing or the cost of lost gear.Received November 27, 2012; accepted September 29, 2013

Panulirus argus virus 1 (PaV1) infection prevalence and risk factors in a Mexican lobster fishery employing casitas

In Bahía de la Ascensión in Mexico, the Caribbean spiny lobster Panulirus argus fishery is based on extensive use of artificial shelters (casitas) that can harbor both juveniles and adults of this highly gregarious species. There is concern that the use of casitas might increase contact transmission of Panulirus argus virus 1 (PaV1). However, a previous study found no evidence for lobster crowding within casitas influencing the prevalence of clinical PaV1 disease, although differences in clinical prevalence were noted between different bay environments. To investigate this more closely, 683 lobsters were sampled from casitas in 2 zones in this bay (Vigía Chico, a shallow low-vegetation zone, and Punta Allen, a deeper dense-vegetation zone) previously found to have the lowest and highest prevalence, respectively, of observed clinical signs. When hemolymph collected from these lobsters was tested by PCR, the prevalence of PaV1 infection was found to be significantly lower in Vigía Chico relative to Punta Allen irrespective of season or the size, sex, or presence of shell injuries on lobsters. Among 714 large commercial-catch lobsters collected throughout the bay, the prevalence of infection was low irrespective of year or sex. For all lobsters tested, the sensitivity (0.510) at which PaV1 infection was detected by observed clinical signs was about half that determined by PCR, but the specificity of clinical signs was absolute (1), indicating that a simple 2× correction factor can be used to accurately estimate PaV1 infection prevalence based on more easily conducted visual assessments of lobsters.

Spatial dynamics in the social lobster Panulirus argus in response to diseased conspecifics

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.

Estimates of exploitation rates of the spiny lobster fishery for Panulirus argus from tagging within the Bahía Espíritu Santo ‘Sian Ka'an’ Biosphere Reserve, Mexican Caribbean

The Caribbean spiny lobster (Panulirus argus) fishery is currently being assessed for a certification process. It is the main economic activity within the Biosphere Reserve of Sian Ka'an-Mexico (SK), which is a marine-protected area where restricted access fishing is allowed. In this study, commercial catch rates were examined, and lobsters over a wide size range were tagged throughout the 2010/2011 fishing season, to assess fishing mortality rates and movement patterns in Bahía Espíritu Santo-SK. Lobster tag recovery data were aggregated into 2-week periods and analysed using a modified Brownie model that was parameterized to account for lobster tag-reporting, and the lobster tag-retention rates. This allowed the estimation of instantaneous rates of natural and fishing mortality, considering catchability and fishing effort. Independent aquaria trials were conducted to better estimate lobster tag retention, tagging-induced mortality and interviews with fishermen were conducted to better estimate lobster tag reporting. Based mainly on legal-sized juveniles with fast growth rates found in casitas, the stock is subject to fishing to a maximum depth of 20 m, because of the prohibition of SCUBA diving and the use of other fishing gear. The Brownie model indicated that exploitation rates within this bay area were high,>0.94. Changes in catch per unit of effort and catchability throughout the season explain how the ‘casita/campo’ system allows for a seasonal replenishment of juveniles and adults, which has kept the landings relatively stable for the past decade.

Integrating Anthropogenic and Climatic Factors in the Assessment of the Caribbean Spiny Lobster (<i>Panulirus argus</i>) in Cuba: Implications for Fishery Management

The Caribbean spiny lobster Panulirus argus , the most valuable Cuban fishery resource, is managed with a set of input and biological controls. The aim of this article was to integrate two indices related water and nutrients supply and tropical cyclones activity in the stock assessment, through internal estimation of the parameters of a spawning stock recruitment function in a statistical catch-at-age analysis. The population dynamics model allowed estimating key Reference Points for management at fixed levels of fishing mortality rate and environmental conditions. The results indicate that the reduction of recruitment and catches in the Cuban spiny lobster fishery could be a result of synergistic cumulative effects because of the anthropogenic reduction of nutrients supplies and the increase of the potential destructiveness of tropical cyclones since 1994, mainly from 2001 on. Although the degradation of the coastal habitat quality in Cuba is apparent and perhaps unavoidable, the assessment of the impact allows implementing management actions for the spiny lobster fishery sustainability. The implementation of annual TAC depending on the stock status, have maintained the fishery around the more conservative Reference Points F 40% and F 0.1 during the current unfavorable environment period.

Assessment of wild spiny lobster stocks on the Brazilian continental shelf

The red spiny lobster Panulirus argus (Latreille, 1804) and the green spiny lobster Panulirus laevicauda (Latreille, 1817) are the most abundant and commercially valuable lobster species on the Brazilian continental shelf. Though sold on the domestic market, the painted spiny lobster (Panulirus echinatus Smith, 1869) and the slipper lobster (Scyllaridae) are of little economic importance and have been the object of very little research. Brazilian spiny lobster fisheries have been in decline for many years due to growth overfishing, including the capture of undersized specimens (>50%). Furthermore, fishing berried females and older lobsters from deeper waters (≥50 m), compromising the reproductive potential of the species and increasing the risk of low recruitment and fishing collapse. The setting of quotas on catches is in itself insufficient to protect Brazilian lobster stocks. Management efforts should instead focus on the enforcement of control measures in order to increase lobster stocks. In this study we make several recommendations: (i) lobster traps should be furnished with escape gaps for undersized lobsters, (ii) the use of undersized lobsters (decoys) in traps should be avoided, (iii) gillnets (“cacoeira”) and artificial shelters (“marambaia”) should be eliminated, (iv) an optimal minimum legal size should be established (80 mm CL for all spiny lobster species and 85 mm CL for slipper lobsters), (v) a maximum legal size should be established (135 mm CL for P. argus and 100 mm CL for P. laevicauda of both sexes), (vi) the capture of berried females should be prohibited, (vii) a closed season should be instituted to protect ovigerous females and ensure recruitment, (viii) establishment of marine reserves or a total closed season to protect the juveniles in nursery areas, (ix) a monitoring program collecting catch and effort data should be implemented to help assess lobster stocks adequately, and, (x) stratified random sampling must be implemented.