Japanese Spiny Lobster Panulirus Japonicus Research Articles

Identification and Physiological Assays of Crustacean Hyperglycemic Hormones in the Japanese Spiny Lobster, Panulirus japonicus.

The Japanese spiny lobster Panulirus japonicus lives on rocky shores and is mainly distributed along the Pacific coast around Japan. Due to the high demand for it, the development of aquaculture systems and increasing its resource volume requires further expansive production. However, a major factor preventing the establishment of aquaculture technology for this lobster is the difficulty with rearing processes from larval to juvenile production. A recent study shed light on the molecular mechanisms underlying larval development from the perspective of physiological functions of endocrine factors such as molting hormones. However, physiological studies of P. japonicus are still lacking. In decapod crustaceans, the X-organ/sinus gland complex is a well-known endocrine system that secretes the crustacean hyperglycemic hormone (CHH)-superfamily peptides that regulate growth, molting, sexual maturation, reproduction, and change in body color. In this study, we identified two CHHs from the sinus glands of P. japonicus using reversed-phase high-performance liquid chromatography in order to elucidate their physiological function for the first time.

Amended larval recruitment model for the Japanese spiny lobster Panulirus japonicus based on new larval records and population genetic data in Taiwan

The spiny lobster Panulirus japonicus (von Siebold, 1824) has a rather restricted distribution in the northwestern Pacific, ranging from Japan to Taiwan and southeastern China. It has been hypothesized that the Japanese populations of this species share a common pool of larvae for recruitment, and that these larvae are transported by the Kuroshio Subgyre. However, it remains unclear how the populations around western Taiwan and southeastern mainland China are maintained, as they are outside the Kuroshio Subgyre. In this work, a final-stage phyllosoma and a puerulus of this species were discovered for the first time in Taiwanese waters and off the southern coast. An extended genetic analysis of the Taiwanese and southeastern Chinese populations of P. japonicus showed that they all share a common gene pool. The larval recruitment hypothesis for P. japonicus was therefore modified by suggesting that its late-stage phyllosoma or puerulus may reach further south to southern Taiwan, with the branch of Kuroshio Current accounting for the larval recruitment of the populations around western Taiwan and southeastern China.

The influence of male size on competitive mating success in the Japanese spiny lobster Panulirus japonicus (von Siebold, 1824) (Decapoda: Palinuridae): implications for broodstock management techniques

The influence of male size on competitive mating success in the Japanese spiny lobster Panulirus japonicus (von Siebold, 1824) (Decapoda: Palinuridae): implications for broodstock management techniques

アマクサアメフラシおよびゾウアメフラシのインクと皮膚抽出物のイセエビに対する摂食阻害作用

Chemical defense using secretion of ink containing purple pigments derived from red algae is common in sea hares. Aplysia juliana, however, prefers green algae, and thus, its ink is white, not purple. Since opaline, the sea hares' other defensive secrwetion, is also white, ink and opaline were not distinguished from each other in previous experiments. Thus, deterrence of this white ink alone towards predators has never been tested. In this study, we tested the deterrence of the white ink of A. juliana as well as the extract of their skin, using the Japanese spiny lobster Panulirus japonicus as a model predator. Parallel experiments on Aplysia gigantea, a sea hare with purple ink, were performed to test whether P. japonicus is deterred by purple ink. The skin extract, but not the white ink, of A. juliana was deterrent. In contrast, purple ink, but not the skin extract, of A. gigantea was deterrent. These results show that the skin of A. juliana contains defensive chemicals against P. japonicus, whereas the white ink itself does not.

Passive acoustic monitoring of Japanese spiny lobster stridulating sounds

The Japanese spiny lobster Panulirus japonicus is an important marine resource in Japan. In order to manage its stock, an effective methodology for population assessments is needed. In this study, we focused on the stridulating sounds produced by spiny lobsters. The stridulating sounds are widely accepted to function as an anti-predator signaling, for potential use in monitoring lobster stocks remotely. An underwater sound recorder was attached on gill nets or lobster pots around Izu Oshima and Niijima islands, within the Izu archipelago, Tokyo, Japan, where lobster fishing is common. Stridulating sounds were manually extracted from each data file. The frequency of stridulating sounds tended to increase on nights with a large tidal change. There was a positive correlation between the frequency of stridulating sounds and the number of lobsters caught in the net or lobster pot. Even in trials where no lobsters were caught, several stridulating sounds could be detected and increased at night. In this study, we describe the sound characteristics of the stridulation, and the trend of nocturnal call productions of this species. This study is the first step towards passive acoustic resource monitoring of Japanese spiny lobsters, which were quite difficult to estimate the density of remotely.

Ontogenetic change of body density and shape of the phyllosoma larvae of the Japanese spiny lobster Panulirus japonicus

ABSTRACT Ontogenetic change in body density and shape of phyllosoma larvae was examined for the Japanese spiny lobster Panulirus japonicus (von Siebold, 1824) using laboratory-cultured specimens from hatching to the final phyllosoma stage before metamorphosing to the puerulus stage. Phyllosomas have a unique body form that is leaf-like and dorso-ventrally compressed with several appendages, and a long planktotrophic life in the ocean. Ontogenetic change was not found in the larval body density, and the mean density (1.097 g cm-3) was greater than the seawater density (1.024 g cm-3), indicating that they must employ strategies to control their buoyancy. The body shape of the phyllosomas changed during development into the puerulus stage where pleopods on the pleon and the pereiopods function as swimming organs and walking legs, respectively. The pleon rapidly developed after the mid-stage VI phyllosoma (10.6 mm body length (BL)). The thoracic pereiopods, including the third maxilliped, that function as swi...

Effect of photoperiod on metamorphosis from phyllosoma larvae to puerulus postlarvae in the Japanese spiny lobster Panulirus japonicus

In order to examine the effect of photoperiod on the metamorphosis from phyllosoma (larval stage) to puerulus (postlarval stage) in Panulirus japonicus, penultimate-stage phyllosomata (376 days old, mean body length = 23.5 mm) were lab-cultured through metamorphosis to pueruli under three photoperiods with light phases of 10, 12, and 14 h (10L, 12L, and 14L) at 25 °C for 90 days. For each light treatment, phyllosomata were cultured in duplicate 7-l elliptical tanks (nine larvae/tank) and fed Artemia and mussel gonad. Our initial observations indicate that the average time required for phyllosomata to reach metamorphosis decreased and the rate of metamorphosis increased as the photoperiod increased. The larvae reared under 10L and 12L underwent repeated molts in the final phyllosoma stage; body lengths at metamorphosis decreased significantly with increasing photoperiod. Under 14L, most larvae had no setae on the margin of pleopods, whereas more than half of the larvae cultured under 10L and 12L had setose pleopods, a clear indicator of overdevelopment. Collectively, our results indicate that a longer photoperiod promotes smooth and regular metamorphosis, whereas a shorter photoperiod results in delayed or suppressed metamorphosis. These findings emphasize the importance of photoperiod as a significant extrinsic factor during the process of metamorphosis, and have important implications in terms of providing a better understanding of larval development and ecology in the wild.

Oral and integumental uptake of free exogenous glycine by the Japanese spiny lobsterPanulirus japonicusphyllosoma larvae

The possibility of direct integumental absorption of the amino acid glycine from a solution in seawater was investigated in 250-260 day old (16.9-50.0 mg wet mass) phyllosoma larvae of the Japanese spiny lobster Panulirus japonicus Von Siebold 1824. The uptake of the amino acid was assessed by autoradiography and liquid scintillation counting (LSC) of larvae incubated with [2-(3)H]glycine and the net uptake was estimated by a time course high-performance liquid chromatography (HPLC) analysis of the concentration of glycine in the incubation medium. Autoradiography revealed the presence of labelled glycine in the cuticle, epidermis and internal tissues (digestive system, muscle, haemocytes) within 30 min of the onset of incubation. Absorption through the integument was confirmed by autoradiography and LSC as glycine uptake was observed even in larvae whose mouths were artificially sealed with cyanoacrylate bond prior to incubation. Scanning electron microscopic examination of the body surface revealed no bacterial population that could have mediated the uptake. HPLC revealed a consistent net uptake (0.29-0.39 micromol g(-1) body mass h(-1)) of glycine in larvae incubated in 6 micromol l(-1) glycine and high individual variation (e.g. absorption or release) in larvae incubated at higher concentrations (30 and 60 micromol l(-1)). Thus, the results of this study provide clear confirmation that, in addition to the known mode of oral feeding on macroscopic food masses, P. japonicus phyllosoma larvae are also able to absorb nutrients directly from the surrounding medium.

Uptake of dissolved free amino acids by spiny lobster Panulirus japonicus phyllosoma larvae

This study examined the ability of late stage (instar XXVI) Japanese spiny lobster Panulirus japonicus phyllosoma larvae to uptake seven l-type amino acids (AAs; aspartic acid, Asp; threonine, Thr; glutamic acid, Glu; glycine, Gly; alanine, Ala; valine, Val; and methionine, Met) from the rearing medium. The time course uptake during incubation for 5 h in solutions containing 1, 2, 5, 10, or 20 μM of each AA was determined using high performance liquid chromatography. There was considerable individual variation in uptake rates and even occasional release of AAs, but larvae showed net uptakes of all seven AAs. Two polar acidic AAs (Glu and Asp) were readily taken up whereas neutral AAs, including three considered as essential for crustaceans (Val, Met, and Thr), had lower uptake rates. Transient releases of AAs by the larvae were common for the AAs with the lowest uptake rates at 1–2 h of incubation. Uptake rates increased with increasing AA concentration but less so for those taken up in larger amounts. Larvae took up AAs to a total of 16.4 μmol/g/h for incubation in the 20 μM solution. The ability to uptake nutrients directly from the medium may be important for the well-being of the larvae.

Characterization of crustin antimicrobial proteins from Japanese spiny lobster Panulirus japonicus

Crustin antimicrobial proteins (PJC1–4) were identified from a phyllosoma library of Japanese spiny lobster, Panulirus japonicus. The deduced amino acid sequences of PJC1–4 contained open reading frames of 130, 139, 124 and 150 amino acid residues, respectively. These proteins contained a glycine-rich region at the N-terminus and 12 conserved cysteine residues containing a single whey acidic protein (WAP) domain at the C-terminus. A phylogenetic tree and sequences alignment analyses revealed that PJC1–4 are more closely related to shrimp crustins than to other lobster crustins. Transcripts of PJC1, 3 and 4 were detected in heart, nerves, intestine, hemocytes, gills and hepatopancreas, while transcripts of PJC2 were detected only in nerves.

Distribution and dispersal of the early larval stages of the Japanese spiny lobster Panulirus japonicus in the East China Sea

The annual distribution and dispersal of early‐stage phyllosoma of the Japanese spiny lobster Panulirus japonicus were examined in the East China Sea and the Sea of Japan off western Japan. Early‐stage larvae were sampled mainly in summer and relatively near the coast off western Kyusyu Island. Few larvae were found in the other three seasons in the East China Sea and the Sea of Japan. This finding suggests that P. japonicus larvae are retained in coastal areas for a few months after hatching until stage V and are transported offshore until autumn, before they grow to stage VI. Examination of archival drifter data off western Kyusyu Island during the spawning season of P. japonicus supported the relatively rapid dispersal of the larvae from the East China Sea near Japan to the Pacific Ocean or the Sea of Japan. Larval transport from the East China Sea to the Pacific Ocean, which is considered to be a main distribution area of middle‐ and late‐stage larvae, would occur in the south at approximately 32–33°N in the East China Sea near western Kyusyu Island.

Expressed sequence tag analysis of phyllosomas and hemocytes of Japanese spiny lobster Panulirus japonicus

Two complementary DNA (cDNA) libraries were constructed from phyllosomas and hemocytes of adult Japanese spiny lobster Panulirus japonicus and a total of 2,673 expressed sequence tags (ESTs) were obtained. After assembly and clustering, 450 and 458 unique sequences were found from the phyllosoma and hemocyte cDNA libraries, respectively. Of these, 114 and 220 ESTs showed significant homologies with known genes in the National Centre for Biotechnology Information (NCBI) database. The remaining sequences were of unknown function. Immune-related genes found in this study include lectin, proteinase inhibitor, prophenoloxidase, heat-shock protein, antimicrobial peptide, and a few putative defense-related proteins.

Characterization of two isoforms of Japanese spiny lobster Panulirus japonicus defensin cDNA

Antimicrobial peptides (AMPs) are components of the innate immune responses that form the first line of host defense against pathogens. In this study, cDNAs of two new isoforms of defensin (designated PJD1 and PJD2) from a Japanese spiny lobster Panulirus japonicus haemocytes cDNA library were cloned and sequenced. PJD1 and PJD2 consist of 656 and 673 nucleotides encoding putative proteins of 66 and 64 amino acids, respectively. The isoforms share 74.2% amino acid identity. In a phylogenetic analysis, the peptides clustered with vertebrate defensins and were closely mostly related to chicken β-defensin. PJD1 and PJD2 were detected in all tissues examined including heart, nerves, intestine, haemocytes, gills and hepatopancreas.

Analysis of mesh breaking loads in cotton gill nets: Possible solution to ghost fishing

A small number of fishers in Chiba Prefecture of eastern Japan use cotton gill nets to catch Japanese spiny lobster Panulirus japonicus. To examine the advantages of cotton gill nets, we analyzed changes in mesh breaking load of a new cotton gill net used in a fishing operation. A new cotton gill net was also soaked in a seawater tank to simulate ghost fishing conditions. The average mesh breaking load of new cotton mesh was 50.3 N. This value decreased to 19.0 N after 38 days (∼912 h), and after 82 days (∼1968 h) the mesh could be easily torn (breaking load 0.07 N). Under fishing conditions, the cumulative soak time was only 744.4 h over 19 months. The average breaking load at the end of this period was 43.1 N, a strength 86% that of the presoaked mesh. The mesh breaking load of a cotton gill net continuously soaked for 744.4 h was 26.1 N, as estimated from tank experiment data. Thus, a cotton gill net maintains reasonable strength under typical use conditions, but will degrade if lost at sea.

Molecular Diet Analysis of Phyllosoma Larvae of the Japanese Spiny Lobster Panulirus japonicus (Decapoda: Crustacea)

To clarify the natural diet of phyllosoma larvae of the Japanese spiny lobster Panulirus japonicus, the sources of 18S rDNA clones obtained from the hepatopancreas were investigated. Of a total of 1537 clones examined, 160 had different restriction profiles from the host larvae, in which 21 restriction types were observed. Nucleotide sequences of 16 of 21 restriction types were successfully determined and their assignments were investigated by homology search and phylogenetic analysis. From seven late-stage larvae collected in spring to early summer, eukaryote DNA molecules of Teleostei, Oomycetes, Mycetozoa, and Fungi were identified. Exogenous DNA from four younger phyllosoma larvae collected in late autumn could not be recovered. A previous study identified DNAs of cnidarians and urochordates in late-stage phyllosoma larvae of a closely related species collected in winter. This indicates that the phyllosoma larvae are opportunistic carnivores, whose diets correlate with the relative abundance of prey organisms in the ambient water.

Population structure of Japanese spiny lobster Panulirus japonicus inferred by nucleotide sequence analysis of mitochondrial COI gene

The mitochondrial DNA sequence for the COI region was determined for 73 Panulirus japonicus individuals collected at three sample locations in Japan. Fifty-one haplotypes, including 69 polymorphic sites without insertion and deletion, were detected, of which three dominant haplotypes were shared among the three sample locations. The nucleotide and haplotype diversities at the three sample locations were in the ranges of 0.009-0.010 and 0.959-0.990, respectively. No significant population subdivision was detected among the sample locations based on the Fst value and net nucleotide substitution rate, and analysis of the molecular variance model (AMOVA). There was no characteristic geographic distribution pattern for these haplotypes. These results indicate there is no genetic differentiation between P. japonicus populations in Japan, and support the hypothesis that benthic individuals of P. japonicus are sustained from a population of a common pool of long-period phyllosoma larvae through long-distance larval transport within the Kuroshio Subgyre.

廃棄貝殻を利用したイセエビの増殖施設の開発

Since 1980s, various artificial reefs for Japanese spiny lobster Panulirus japonicus resource have been deployed in the coastal waters at Pacific and East China Sea. However, their structural feature was to provide only nest rooms but prey items, considered as another important factor to attract the lobsters. We have developed the new concept reef with waste shell, which cultivate prey organisms efficiently. In this study, we will show the following results of the five-year monitoring after this reef installation. (1) The prey animals increased to 45.0kg m-3 in total weight on the reefs. (2) Adult lobsters were recorded for the first time in 21st month, and reached to 12.3 indv. m-3 in 57th month. (3) Egg-brooding adults, Puerulus larvae and juvenile were found in the reef. In conclusion, we are convinced the reef with shells is well suited to the all-stages lobsters for dwelling, feeding and reproducing place. And (4) other valuable species such as top shell, abalone and rockfish were found in the reef. Therefore, it is expected this technique to apply habitats for diverse species is also very effective in creation of the eco-friendly harbor area.

The Actual Situation About the Habitat of a Japanese Spiny Lobster Panulirus Japonicus in Fishing Port Facilities

In this paper, we paid attention to Japanese spiny lobster Panulirus japonicus which lived in the fishing port facilities, and to contribute to the development of the fishing port facilities where the function of propagation had been strengthened. Three fishing ports were selected where P. japonicus was distributed in Japan and field survey was carried out about the living density, the habitat, and catch yield from May through December, 2006. As a result, P. japonicus lived around the fishing port entrance and appeared from water depth 2m (the caisson, the armor block, and the wave dissipating concreate block) to 10m. In addition, we report it some knowledge about the appearance in fishing port according to growth stage and the methods of presuming the amount of the resource of P. japonicus.

Larval molting and growth of the Japanese spiny lobster Panulirus japonicus under laboratory conditions

Ten newly hatched phyllosoma of Panulirus japonicus were cultured individually to monitor body length (BL) and intermolt period, and 2000 were cultured in groups to sample specimens for measurement of body weight. Phyllosoma were fed with Artemia and mussel gonad; the culture seawater temperature was 24–26°C. The individually cultured phyllosoma showed an increment in body length by the first molt of approximately 0.5 mm, and the molt increment increased to approximately 1 mm at 5 mm BL; it was constant to 15 mm BL. The reafter, the molt increment increased exponentially. The duration of the first instar was 6–7 days. Instar duration increased with development up to approximately 2 weeks at the 20th instar (≈16 mm BL) and then became constant. Of the 10 larvae reared individually, five metamorphosed to the puerulus stage. The entire phyllosoma life ranged from 245–326 days (mean 289.0 days), and the number of instars ranged from 22–29 (mean 26.2). Body length in the final instar ranged from 28.50–33.10 mm (mean 30.280 mm). For the phyllosoma cultured in groups, relationships between BL and wet/dry body weights (WW/DW, mg) were expressed as exponential equations: WW=0.0686BL2.2023 and DW=0.0209BL2.1905.

Effects of photoperiod and temperature on ovarian development and spawning of the Japanese spiny lobster Panulirus japonicus

In order to examine the effects of photoperiod and temperature on ovarian development and spawning in the Japanese spiny lobster Panulirus japonicus, spent female lobsters were cultured with male lobsters under six conditions of short (10 L) or long (14 L) photoperiod at 13, 19 or 25 °C during the months December–March. Under the long photoperiod, ovarian development progressed at all temperatures and at higher temperatures, development was accelerated. Spawning occurred in all the females kept at 25 °C and the ovaries in females at 19 °C also developed up to the point of approaching spawning at the end of the experiment. Ovarian development under the short photoperiod depended on temperature. It progressed slowly at 13 °C, whereas it was prevented or considerably delayed at 19 and 25 °C. These results suggest that both photoperiod and temperature are important factors controlling ovarian development and spawning for P. japonicus. When spent females were cultured under conditions of 10, 11.25, 12.5 and 14 L at 25 °C during the months December–March, ovarian development was suppressed at photoperiods, shorter than 14 L, whereas it progressed smoothly at 14 L and most females spawned. Hence, the critical photoperiod for ovarian development and spawning at 25 °C appears to be between 12.5 and 14 L.