Spiny Lobster Species Research Articles

Pathogenicity and Infection Cycle of Vibrio owensii in Larviculture of the Ornate Spiny Lobster (Panulirus ornatus)

The type strain of Vibrio owensii (DY05) was isolated during an epizootic of aquaculture-reared larvae (phyllosomas) of the ornate spiny lobster (Panulirus ornatus). V. owensii DY05 was formally demonstrated to be the etiological agent of a disease causing rapid and reproducible larval mortality with pathologies similar to those seen during disease epizootics. Vectored challenge via the aquaculture live feed organism Artemia (brine shrimp) caused consistent cumulative mortality rates of 84 to 89% after 72 h, in contrast to variable mortality rates seen after immersion challenge. Histopathological examination of vector-challenged phyllosomas revealed bacterial proliferation in the midgut gland (hepatopancreas) concomitant with epithelial cell necrosis. A fluorescent-protein-labeled V. owensii DY05 transconjugant showed dispersal of single cells in the foregut and hepatopancreas 6 h postexposure, leading to colonization of the entire hepatopancreas within 18 h and eventually systemic infection. V. owensii DY05 is a marine enteropathogen highly virulent to P. ornatus phyllosoma that uses vector-mediated transmission and release from host association to a planktonic existence to perpetuate transfer. This understanding of the infection process will improve targeted biocontrol strategies and enhance the prospects of commercially viable larviculture for this valuable spiny lobster species.

Genetic Isolation between the Western and Eastern Pacific Populations of Pronghorn Spiny Lobster Panulirus penicillatus

The pronghorn spiny lobster, Panulirus penicillatus, is a circumtropical species which has the widest global distribution among all the species of spiny lobster, ranging throughout the entire Indo-Pacific region. Partial nucleotide sequences of mitochondrial DNA COI (1,142–1,207 bp) and 16S rDNA (535–546 bp) regions were determined for adult and phyllosoma larval samples collected from the Eastern Pacific (EP)(Galápagos Islands and its adjacent water), Central Pacific (CP)(Hawaii and Tuamotu) and the Western Pacific (WP)(Japan, Indonesia, Fiji, New Caledonia and Australia). Phylogenetic analyses revealed two distinct large clades corresponding to the geographic origin of samples (EP and CP+WP). No haplotype was shared between the two regional samples, and average nucleotide sequence divergence (Kimura's two parameter distance) between EP and CP+WP samples was 3.8±0.5% for COI and 1.0±0.4% for 16S rDNA, both of which were much larger than those within samples. The present results indicate that the Pacific population of the pronghorn spiny lobster is subdivided into two distinct populations (Eastern Pacific and Central to Western Pacific), with no gene flow between them. Although the pronghorn spiny lobster have long-lived teleplanic larvae, the vast expanse of Pacific Ocean with no islands and no shallow substrate which is known as the East Pacific Barrier appears to have isolated these two populations for a long time (c.a. 1MY).

Behavioral responses to variable predation risk in the California spiny lobster Panulirus interruptus

Shelter dwelling and gregariousness are behavioral strategies used by benthic marine organisms to reduce the risk of predator-induced mortality. For spiny lobsters, the relative and syner- gistic success of shelter dwelling and aggregation in reducing mortality may vary with the perceived risk of predation as well as the availability and size distribution of conspecifics and shelters. We tested how these factors influence antipredator behavior in the California spiny lobster Panulirus interruptus in southern California kelp forests. We measured shelter and lobster characteristics, predator density, relative lobster mortality outside of shelter, and quantified lobster antipredator behaviors in (1) the La Jolla Ecological Reserve (LJER), a marine protected area with high densities of large fishes known to be lobster predators, and (2) the Point Loma kelp forest, a nearby, heavily fished area. Predator densities and the relative mortality of tethered juvenile and adult lobsters were much higher in the LJER than in Point Loma, as was mean lobster size. In response to higher preda- tion risk, solitary lobsters in the LJER used shelters more closely scaled to their body size than lob- sters in Point Loma, thereby restricting predator access to shelters. In addition, aggregations of 2 or more lobsters were more frequent than expected by chance in the LJER, but not in Point Loma. Lobsters in Point Loma commonly were found outside of shelter during the day, whereas no lobsters ever were observed outside of shelter during daylight hours in the LJER. Overall, our results indicate that California spiny lobsters modify their antipredatory behaviors with level of predation risk and that behaviors designed to minimize predator-induced mortality are similar between California spiny lobsters and other spiny lobster species.

Moult regulation in the South African spiny lobster, Jasus lalandii

Event Abstract Back to Event Moult regulation in the South African spiny lobster, Jasus lalandii Heather Marco1* 1 University of Cape Town, Zoology Department, South Africa Jasus lalandii is a cold water spiny lobster species that occurs off the western shore of South Africa and which does not have a terminal moult; hence, growth continues in adulthood, concurrently with reproductive activities. During the moult cycle, steroid hormones (ecdysteroids) are produced by paired thoracic glands called the Y-organs (YOs). The titre of ecdysteroids fluctuates in a consistent pattern during a moult cycle, and ecdysis is triggered by a high titre of this steroid hormone. Ecdysteroidogenesis is inhibited by neuropeptide hormones that are produced in the X-organ - sinus gland (XO-SG) system in the eyestalk. These neuropeptides have been identified as moult-inhibiting hormone (MIH) and crustacean hyperglycaemic hormone (cHH); the latter is also essential for intermediate metabolism (elevating glucose concentration in the haemolymph). To understand the control of moulting in J. lalandii, homologous biological assays with HPLC-purified cHH and MIH were carried out to investigate the action of these hormones during intermoult, at different doses, on metabolism (in vivo) and growth (in vitro). Assays with MIH on YOs at different stages of the moult cycles were also performed, as well as investigations into the second messenger pathways involved in regulation of the moult cycle of J. lalandii. I will report on these findings in the spiny lobster and discuss the data in a comparative context. Funding from the National Research Foundation and UCT is gratefully acknowledged. Keywords: comparative endocrinology Conference: 25th Conference of the European Comparative Endocrinologists, Pécs, Hungary, 31 Aug - 4 Sep, 2010. Presentation Type: Conference Presentation Topic: Comparative endocrinology Citation: Marco H (2010). Moult regulation in the South African spiny lobster, Jasus lalandii. Front. Endocrinol. Conference Abstract: 25th Conference of the European Comparative Endocrinologists. doi: 10.3389/conf.fendo.2010.01.00025 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 26 Aug 2010; Published Online: 29 Aug 2010. * Correspondence: Dr. Heather Marco, University of Cape Town, Zoology Department, Cape Town, South Africa, heather.marco@uct.ac.za Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Heather Marco Google Heather Marco Google Scholar Heather Marco PubMed Heather Marco Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Palinustus mossambicus Barnard, 1926 (Crustacea: Decapoda: Achelata: Palinuridae); morphology of the puerulus stage

Two adults of the rare buffalo blunthorn spiny lobster, Palinustus mossambicus Barnard, 1926 and a puerulus specimen were found while curating material from the first R/V “Dr. Fridtjof Nansen” expedition to the Western Indian Ocean. Furthermore, another puerulus-stage specimen of this spiny lobster species was found caught near Zanzibar, Tanzania. The morphological characters of the puerulus specimens indicated that they belonged to P. mossambicus, although the puerulus stage is somewhat dorsoventrally flattened, and has proportionally large pleopods. This constitutes the first puerulus description for the spiny lobsters of the genus Palinustus.

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.

The acoustic mechanics of stick–slip friction in the California spiny lobster (Panulirus interruptus)

The dynamic interplay between static and sliding friction is fundamental to many animal movements. One interesting example of stick-slip friction is found in the sound-producing apparatus of many spiny lobster species (Palinuridae). The acoustic movements of the spiny lobster's plectrum over the file are generated by stick-slip friction between the two surfaces. We examined the microscopic anatomy, kinematics, acoustics and frictional properties of the California spiny lobster (Panulirus interruptus) toward the goal of quantitatively characterizing the frictional and acoustic mechanics of this system. Using synchronous high-speed video and sound recordings, we tested whether plectrum kinematics are correlated with acoustic signal features and found that plectrum velocity is positively correlated with acoustic amplitude. To characterize the frictional mechanics of the system, we measured frictional forces during sound production using excised plectrums and files. Similar to rubber materials sliding against hard surfaces, the static coefficient of friction in this system was on average 1.7. The change in the coefficient of friction across each stick-slip cycle varied substantially with an average change of 1.1. Although driven at a constant speed, the plectrum slipped at velocities that were positively correlated with the normal force between the two surfaces. Studies of friction in biological systems have focused primarily on adhesion and movement, while studies of stick-slip acoustics have remained under the purview of musical acoustics and engineering design. The present study offers an integrative analysis of an unusual bioacoustic mechanism and contrasts its physical parameters with other biological and engineered systems.

Molecular phylogeny of the spiny lobster genus Palinurus (Decapoda: Palinuridae) with hypotheses on speciation in the NE Atlantic/Mediterranean and SW Indian Ocean

Sequence data derived from the mitochondrial DNA 16S rRNA and COI genes were used to determine the phylogenetic relationships among six Palinurus spiny lobster species. Three species ( P. charlestoni, P. elephas, and P. mauritanicus) occur in the northeastern Atlantic/Mediterranean, and the others ( P. barbarae, P. delagoae and P. gilchristi) inhabit the southwestern Indian Ocean. Parsimony and model based phylogenetics strongly supported the monophyly of the genus. A combined parsimony analysis based on 1001 bp and 274 parsimony informative characters recovered the most resolved phylogeny with >70% bootstrap support for associations among species. The Atlantic P. charlestoni consistently clusters nested within the Indian Ocean clade, and the mtDNA sequence divergence between the two most distant species is 8.24%. If the northward collision of Africa with Eurasia in the Miocene caused the final physical separation between the Atlantic and Indian Ocean taxa, then the Palinurus mtDNA (COI and 16S combined) evolved no faster than 0.18% (lower bound) to 0.36% (upper bound) per lineage per million years. The six extant species occur in the pathways of the North Atlantic and South Indian Ocean gyres, and hypotheses on their radiation are developed relative to the strengthening of boundary currents in the Miocene and life history traits congruent with survival in strong ocean currents.

Loss of Escape-Related Giant Neurons in a Spiny Lobster,Panulirus argus

When attacked, many decapod crustaceans perform tailflips, which are triggered by a neural circuit that includes lateral giant interneurons, medial giant interneurons, and fast flexor motor giant neurons (MoGs). Slipper lobsters (Scyllaridae) lack these giant neurons, and it has been hypothesized that behavioral (e.g., digging) and morphological (e.g., flattening and armor) specializations in this group caused the loss of escape-related giant neurons. To test this hypothesis, we examined a species of spiny lobster, Panulirus argus. Spiny lobsters belong to the sister taxon of the scyllarids, but they have a more crayfish-like morphology than scyllarids and were predicted to have escape-related giant neurons. Ventral nerve cords of P. argus were examined using paraffin-embedded sections and cobalt backfills. We found no escape-related giant neurons and no large axon profiles in the dorsal region of the nerve cord of P. argus. Cobalt backfills showed one fewer fast flexor motor neuron than in species with MoGs and none of the fast flexor motor neurons show any of the anatomical specializations of MoGs. This suggests that all palinuran species lack this giant escape circuit, and that the loss of rapid escape behavior preceded, and may have driven, alternative predator avoidance and anti-predator strategies in palinurans.

Defense mechanisms and antipredator behavior in two sympatric species of spiny lobsters, Panulirus argus and P. guttatus

The congeneric spiny lobsters Panulirus argus and P. guttatus co-occur throughout the Caribbean Sea, where they may share the coral reef habitat. Despite their phylogenetic closeness, both species have many different life-history traits that may partially explain their coexistence. However, even though both species may face the same predators, their defense mechanisms and antipredator strategies had not been compared. We compared the performance between species in 18 morphological and behavioral defense mechanisms commonly expressed by most spiny lobsters, including predator-avoidance mechanisms (activity schedule, sheltering behavior, delay to disturbance, and effect of conspecific damage-released scents on shelter choice) as well as antipredator mechanisms (body size, several parameters of the escape response and limb autospasy, clinging strength, antennal strength, and cooperative defense). As hypothesized, both species expressed all these defense mechanisms (except cooperative defense, shown only by P. argus), reflecting their phylogenetic closeness, but performed significantly differently in most, in accordance with their particular ontogenetic traits. Their comparative performance in individual defense mechanisms as well as the antipredator strategies displayed by groups of lobsters of each species in the presence of a common predator (the triggerfish Balistes vetula) showed that, in general, the defensive behavioral type of P. argus is more bold and that of P. guttatus more shy. Therefore, their distinct defensive behaviors contribute to their niche differentiation.

A new species of spiny lobster, Palinurus Barbarae (Decapoda, Palinuridae) from Walters Shoals on the Madagascar Ridge

[A new species of spiny lobster, Palinurus barbarae , is described from catches made at Walters Shoals, a high-seas submerged seamount on the Madagascar Ridge, south-western Indian Ocean. Morphology and mitochondrial DNA analyses place the species closest to Palinurus delagoae , which is found in deep-shelf waters off South Africa and Mozambique. The carapace of P. barbarae is more spinose than that of P. delagoae , and the posterior carapace rim terminates in a smooth groove and raised angular lip (groove absent in P. delagoae ). Spine counts on antennal peduncles and pleural edges of abdominal somites further differentiate between the two species. Our findings cast some doubt on the present taxonomic classification of Palinurus in the south-western Indian Ocean, particularly on the status of the Palinurus spp. from southern Madagascar, approximately 400 nautical miles north of Walters Shoals. Eine neue Langustenart, Palinurus barbarae , wird aus Fangen vom Walters Shoals, einem untermeerischen Seeberg des Madagaskar-Ruckens, im sudwestlichen Indischen Ozean beschrieben. Nach Analysen des Korperbaus und der mitochondrialen DNA steht die neue Art Palinurus delagoae am nachsten, die in groseren Tiefen auf dem Schelf vor Sudafrika und Mozambique vorkommt. Der Carapax von P. barbarae ist bestachelter als der von P. delagoae und sein Hinterrand endet in einer glatten Furche und einer erhobenen Lippe an der Ecke (Furche fehlt bei P. delagoae ). Auserdem unterscheiden sich beide Arten in der Dornenzahl auf den Grundgliedern der Antennen und an den Pleuralrandern der Pleonsegmente. Durch unsere Befunde ergeben sich Zweifel an der gultigen taxonomischen Einordnung der Palinurus -Arten des sudwestlichen Indischen Ozeans. Insbesondere betrifft das den Status der Arten von Sudmadagaskar, das ungefahr 400 Seemeilen nordlich von Walters Shoals gelegen ist. , A new species of spiny lobster, Palinurus barbarae , is described from catches made at Walters Shoals, a high-seas submerged seamount on the Madagascar Ridge, south-western Indian Ocean. Morphology and mitochondrial DNA analyses place the species closest to Palinurus delagoae , which is found in deep-shelf waters off South Africa and Mozambique. The carapace of P. barbarae is more spinose than that of P. delagoae , and the posterior carapace rim terminates in a smooth groove and raised angular lip (groove absent in P. delagoae ). Spine counts on antennal peduncles and pleural edges of abdominal somites further differentiate between the two species. Our findings cast some doubt on the present taxonomic classification of Palinurus in the south-western Indian Ocean, particularly on the status of the Palinurus spp. from southern Madagascar, approximately 400 nautical miles north of Walters Shoals. Eine neue Langustenart, Palinurus barbarae , wird aus Fangen vom Walters Shoals, einem untermeerischen Seeberg des Madagaskar-Ruckens, im sudwestlichen Indischen Ozean beschrieben. Nach Analysen des Korperbaus und der mitochondrialen DNA steht die neue Art Palinurus delagoae am nachsten, die in groseren Tiefen auf dem Schelf vor Sudafrika und Mozambique vorkommt. Der Carapax von P. barbarae ist bestachelter als der von P. delagoae und sein Hinterrand endet in einer glatten Furche und einer erhobenen Lippe an der Ecke (Furche fehlt bei P. delagoae ). Auserdem unterscheiden sich beide Arten in der Dornenzahl auf den Grundgliedern der Antennen und an den Pleuralrandern der Pleonsegmente. Durch unsere Befunde ergeben sich Zweifel an der gultigen taxonomischen Einordnung der Palinurus -Arten des sudwestlichen Indischen Ozeans. Insbesondere betrifft das den Status der Arten von Sudmadagaskar, das ungefahr 400 Seemeilen nordlich von Walters Shoals gelegen ist. ]

Changes in lipid and fatty acid composition of late larval and puerulus stages of the spiny lobster ( Panulirus cygnus) across the continental shelf of Western Australia

The feeding of the late larval stages of the spiny lobster, Panulirus cygnus, and the energy reserves used by the non-feeding post-larvae for crossing the continental shelf of Western Australia were examined through their lipid composition. Lipid was a significant component of the biomass of all larval and post-larval samples (range 63–213 mg g − 1 of dry biomass). The fatty acid profiles of late stage larvae (8–9) suggest that they were feeding on salps and small crustaceans, such as euphausids, from oligotrophic pelagic communities where herbivorous and microbial grazing is an important basis to the food web. There was a marked decrease in lipid content of post-larvae progressively across the continental shelf, and this corresponded closely with decreasing dry mass, suggesting that post-larvae were using lipid as an energy source during cross-shelf movement at a rate of 1.6 J km − 1 . This is considerably lower than for other spiny lobster species, suggesting that the post-larvae of the western rock lobster may use physical processes as well as active swimming for onshore transport. This may help to explain the large inter-annual variability in the post-larval settlement of this species, which is closely related to differences in weather patterns capable of greatly varying onshore advection processes.

Status of the major lobster fisheries in India

Commercial exploitation of lobsters from the Indian seas began in the 1950s. Annual landings have been declining from a peak of 4075 t in 1985 to 1364 t in 2002. Major fisheries were located on the north‐west, south‐west, and south‐east coasts. Among the 12 species recorded, only four species of spiny lobsters (three littoral and one deep sea) and one species of slipper lobster are commercially important. At Kayalpattinam and Tharuvaikulam, on the south‐east coast, lobster landings sharply declined for the gill‐net fishery. Of the two species that contributed to the fishery, Panulirus ornatus and Panulirus homarus, the latter has been more affected owing to high vulnerability to fishing activities. Catch composition analysis of the trammel‐net fishery showed that 35% of the landings consisted of P. homarus in the size range of 23–50 mm carapace length. On the north‐west coast, the spiny lobster Panulirus polyphagus and the slipper lobster Thenus orientalis are incidentally caught in trawl nets. However, the fishery for T. orientalis in the waters off Mumbai lasted only up to 1994. Large‐scale exploitation of spawning females, which formed 60% of the total catch, might have been detrimental to the recruitment process resulting in rapid decline and total collapse of the fishery. Abundance of P. polyphagus reached its maximum during September, constituting 23% of the average annual landing during 1988–2002. A high exploitation ratio (>0.7) indicated over‐fishing of the stock. Repeated spawning and high annual egg production are probably responsible for sustaining the stock, despite over‐exploitation. Major problems confronting the resource management of the multi‐gear and multi‐species lobster fisheries in India are discussed. An operational project, involving fisher community, has been taken up for creating awareness of the need for sustainable exploitation of the resource. Regulatory measures, such as closure of the fishery during the peak of the breeding season, ban on trammel‐net, mandatory release of egg‐bearing lobsters, and establishment of lobster sanctuaries are suggested to the State Governments for implementation.

How do spiny lobster post‐larvae find the coast?

The larvae or phyllosomes of many species of spiny lobsters (Palinuridae) are known to complete their development in offshore oceanic waters. Phyllosomes metamorphose to non‐feeding, nektonic post‐larvae or pueruli, which move into shallow coastal waters where they settle to become benthic dwelling juveniles. There is growing evidence that the movement of pueruli is directed toward the coast rather than a process of random dispersal. The migration inshore by the non‐feeding pueruli is likely to be one of the more extreme examples of onshore orientation among marine organisms, but is still poorly understood. This article provides a synthesis of the current state of knowledge of the possible cues and sensory mechanisms that might be used by pueruli of spiny lobsters for orienting toward the coast from offshore waters. The review is used to identify the potential cues that would benefit from future research efforts.

Seasonal variations in chemical response to conspecific scents in the spotted spiny lobster, Panulirus guttatus

Chemical response to conspecific scents mediate aggregations in some species of spiny lobsters, but patterns of codenning of adult lobsters in their natural habitats vary widely. This is so for Panulirus guttatus, a small, sedentary, obligate reef‐dwelling species with a protracted, almost year‐round reproductive season. We hypothesised that changes in patterns of aggregation may vary with the intensity of reproductive activity in the population, which in turn may cause changes in responses to conspecific scents. To test this hypothesis, we conducted three laboratory experiments with Y‐mazes to test for seasonal variations in gender‐related and size‐related response to conspecific scents in mature P. guttatus. When reproductive activity (RA) was high (experiment High‐RA, 67.4% reproductive females), males responded significantly to scents of conspecifics of both genders, but females only to the scent of females. When reproductive activity had not yet reached its yearly lowest point (experiment Medium‐RA, 50.0% reproductive females), only females responded significantly to scents of other females, and when reproductive activity was at its lowest (experiment Low‐RA, 4.8% reproductive females) no treatment yielded significant responses. However, results of the size‐related treatments showed that only large individuals responded significantly to scents of other large lobsters during the High‐RA experiment, whereas during the Medium‐RA only small individuals responded to scents of both small and large lobsters. These results are in accordance with previously observed size‐dependent reproduction in P. guttatus over the protracted reproductive season. Therefore, chemical response to conspecific scents in P. guttatus vary with season, gender, and size and may influence co‐denning patterns of mature individuals in the reef habitat.

HOMING AND ORIENTATION IN THE SPOTTED SPINY LOBSTER, PANULIRUS GUTTATUS (DECAPODA, PALINURIDAE), TOWARDS A SUBTIDAL CORAL REEF HABITAT

Panulirus guttatus (Latreille, 1804) is a sedentary, non-migratory species of spiny lobster that lives in the coral reef habitat throughout its benthic life. Homing and orientation of P. guttatus were investigated through experimental displacements of individual lobsters. Lobsters were caught in fixed traps deployed around three coral patches along a reef tract in northern Quintana Roo, Mexico. A total of 145 adult lobsters were tagged and individually released in one of four compass directions corresponding to the following sites as related to their home reef patches: in the reef lagoon (310?, ~W), along the axis of the reef tract (20?, ~N, or 200?, ~S) and in the fore-reef (100?, ~E). In each direction, individuals were displaced over 50, 100, or 200 m away from their point of capture. Thirty lobsters were recaptured, 29 of which in the same area of the reef patch where they had been initially captured, regardless of the time elapsed (1-146 days). The proportion of recaptured lobsters was independent of the direction and distance of release when lobsters were displaced 50 and 100 m into the reef lagoon or along the axis of the reef, but no lobsters were recaptured from a distance of 200 m along the axis of the reef. Hence, the familiar home range of P. guttatus appears to lie within a radius of 100 m along the reef tract, and within this home range individuals possibly use several crevices as refuges. A tethering experiment showed that lobsters significantly moved towards the reef when released on bare sand 500 m away from the reef. Wave surge may have oriented the lobsters towards the reef. These results indicate that, despite their sedentary, non-migratory nature, adult male and female P. guttatus show homing and orientation abilities.

GROWTH AND MINIMUM SUITABLE CATCH SIZE OF SPINY LOBSTERS, PANULIRUS PENICILLATUS (OLIVIER, 1791) AND PANULIRUS LONGIPES BISPINOSUS BORRADAILE, 1899 (DECAPODA, PALINURIDAE) IN THE SOUTHERN LAGOON OF NEW CALEDONIA

Panulirus penicillatus and Panulirus longipes bispinosus are the main species of spiny lobsters caught by commercial fishermen in the New Caledonian lagoon. The growth of the males and females of these two species is described by a Von Bertalanffy curve based on observing growth in captivity and in the field, and according to the statistical analysis of cephalothoracic length-frequency histograms obtained from commercial catches. A minimum suitable catch size has been calculated from the study of the males of P. penicillatus, which have the most rapid growth. For practical reasons, due to the artisanal frame of this fishery, this limit size (Cephalothorax Lengthlim = 7.5 cm) is recommended for both species and both sexes.

Characterization and sequence elucidation of a novel peptide with molt-inhibiting activity from the South African spiny lobster, Jasus lalandii

We have isolated a peptide from extracts of sinus glands from a South African spiny lobster species, Jasus lalandii, by high-performance liquid chromatography (HPLC) and identified it as a putative molt-inhibiting hormone (MIH) by (i) an in vitro assay with J. lalandii Y-organs to measure the inhibition of ecdysteroid synthesis and (ii) an immunoassay using antiserum raised against MIH of the edible crab. The MIH of J. lalandii has 74 amino acid residues, a molecular mass of 9006 Da, a free N-terminus and an amidated C-terminus. The full primary sequence has been obtained from sequencing various digest fragments (tryptic, endoproteinase Asp-N, cyanogen bromide) of the unreduced (native) peptide: RFTFDCPGMMGQRYLYEQVEQVCDDCYNLYREEKIAVNCRENCFLNSWFTVCLQATMREHETPRFDIWRSIILKA-NH 2. Structural comparisons with other peptides show that the J. lalandii MIH belongs to the peptide family which includes the crustacean hyperglycemic hormone, molt-inhibiting hormone and vitellogenesis-inhibiting hormone (cHH/MIH/VIH). This novel peptide has 36–43% sequence identity to putative MIHs from other decapod crustaceans and 32–34% identity to the two cHH peptides previously identified in this spiny lobster species. This is the first report of a peptide with MIH activity in the Palinuridae infraorder.

Demersal Fisheries of the Arabian Sea, the Gulf of Oman and the Arabian Gulf

The demersal fisheries of the Arabian Sea, the Gulf of Oman and the Arabian Gulf are reviewed. The region comprises eight countries: Oman, United Arab Emirates (U.A.E.), Qatar, Saudi Arabia, Bahrain, Kuwait, Iraq and Iran. Over 350 commercial fish species, eight shrimp species, two spiny lobster species, one shovel nose lobster species, one cuttlefish species, one crab species, and one abalone species support the demersal fisheries in the continental shelves of the three regions. Artisanal and industrial vessels with over 120 000 fishermen were involved in demersal fisheries. Fishing boats include fish and shrimp trawlers (wooden and steel hulled), large wooden boats (dhow) with inboard engines, small dhows with outboard engines, and fibreglass boats. Fishing gear consists of trawls, bottom gill nets, traps (wire mesh and plastic types), barrier traps, hand lines, and bare hands and knives (to dislodge abalone). Demersal fish (primarily Lethrinidae, Sparidae, Serranidae, Siganidae, Sciaenidae, Stromateidae, Lutjanidae, Trichiuridae, and Nemipteridae) and shrimp (primarily Penaeus semisulcatus , Metapenaeus affinis , Parapenaeopsis stylifera , and Penaeus merguiensis ) were the two commercial demersal resources. Approximately 198 000–214 000 tonnes (t) of demersals were landed annually during 1988–1993, accounting for nearly 40% of the total marine landings (475 000–552 000 t). This percentage, however varied among countries: 25% in Oman, 32% in U.A.E., 71% in Qatar, 52% in Saudi Arabia, 56% in Bahrain, 55% in Kuwait, close to 100% in Iraq, and 41% in Iran. Fishing effort on certain stocks may have been below the optimum level (e.g. certain Omani demersal fish), near the optimum level (e.g. Omani shrimp), or above the optimum level (e.g. Arabian Gulf shrimp and demersal fish). Overexploitation led to restriction of fishing effort by limiting fishing licences, regulating fishing gear (mesh size) and capture size, closing fishing areas, restricting fishing season, and banning certain fisheries. However, fisheries management was hampered by lack of appropriate management regulations, enforcement and data on most stocks. Pollution and degradation of nursery areas were also affecting the productivity of fisheries resources. To achieve sustainable demersal fisheries, maintaining a healthy marine environment, reducing fishing effort, and strictly enforcing closed seasons and closed areas are needed. These measures are being implemented with varying degrees of success by all the countries.

The cause and consequence of ontogenetic changes in social aggregation in New Zealand 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 188:179-191 (1999) - doi:10.3354/meps188179 The cause and consequence of ontogenetic changes in social aggregation in New Zealand spiny lobsters Mark J. Butler IV1,*, Alistair B. MacDiarmid2, John D. Booth2 1Department of Biological Sciences, Old Dominion University, Norfolk, Virginia 23529-0266, USA 2National Institute for Water and Atmospheric Research, PO Box 14-901, Kilbirnie, Wellington, New Zealand *E-mail: mbutler@odu.edu ABSTRACT: Ontogenetic changes in the behavior, spatial distribution, or habitat use of a species are presumably adaptations to ecological forces that differ in their effect on various life stages. The New Zealand rock lobster Jasus edwardsii is one of several species of spiny lobster that exhibits dramatic ontogenetic shifts in sociality and spatial distribution, and we tested whether such changes are adaptive. We first surveyed several natural populations of J. edwardsii to document size-specific differences in aggregation. To determine if chemical cues discharged by conspecifics promote aggregation of certain ontogenetic stages, we tested the responsiveness of lobsters of 3 ontogenetic stages (early benthic juvenile, juvenile, and subadult) to the chemical cues produced by conspecifics of different sizes. Finally, we tethered lobsters of different ontogenetic stages alone and in groups to test the effect of lobster size and aggregation on mortality. Our results offer compelling evidence that pre-reproductive J. edwardsii undergo an ontogenetic change in sociality that alters their spatial distribution and survival. Our field surveys show that J. edwardsii are solitary as early benthic juveniles and become social and aggregate as they grow larger. We then demonstrate, using laboratory experiments, that there is a size-specific increase in the response of pre-reproductive J. edwardsii to the chemical cues of larger conspecifics which facilitates these ontogenetic changes in aggregation. Finally, our tethering results confirm that this change in social condition is selectively advantageous: aggregation does not increase the survival of small lobsters, but larger lobsters survive better in groups. Thus, in this study we demonstrate the linkage between ontogenetic changes in the spatial distribution of a species, the behavioral process that creates the pattern, and the selective advantage conferred by these developmental changes. KEY WORDS: Spiny lobster · Rock lobster · Jasus edwardsii · Ontogeny · Sociality · Aggregation · Predation Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 188. Publication date: November 03, 1999 Print ISSN:0171-8630; Online ISSN:1616-1599 Copyright © 1999 Inter-Research.