Spiny Lobster Panulirus Homarus Research Articles

Morphological and molecular identifications of ectoparasites infesting the gills of scalloped spiny lobster Panulirus homarus Linnaeus, 1758

Abstract. Kismiyati, Hidayat YT, Amin M. 2024. Morphological and molecular identifications of ectoparasites infesting the gills of scalloped spiny lobster Panulirus homarus Linnaeus, 1758. Biodiversitas 25: 372-378. Ectoparasite infestation has been reported to cause stress, weaken the immune system, and disturb respiratory systems, which lead to death in cultured spiny lobsters. Many lobster farmers have reported an infestation of ectoparasites in cultured scalloped spiny lobsters in West Nusa Tenggara, Indonesia. However, fewer studies have been conducted to identify the ectoparasite-infesting scalloped spiny lobster cultured in West-Nusa Tenggara Province. Thus, using morphological and molecular approaches, the present study aimed to identify ectoparasites infesting scalloped spiny lobsters (Panulirus homarus Linnaeus, 1758). A total of 30 scalloped spiny lobsters were collected from lobster farmers at Ekas, East Lombok, West Nusa Tenggara, Indonesia, and ectoparasites were observed and identified morphologically under a microscope as well as confirmed using CO1 gene sequences. The results showed that the ectoparasites were morphologically identified as Octolasmis angulata Aurivillius, 1894 and Octolasmis lowei Darwin, 1852. Similarly, based on the mtDNA sequence of the COI region (~721 bp length), the ectoparasite was also referred to O. angulata (95.65% similarity) and Octolasmis lowei (~683 bp length) with a similarity of 98.75%. These results suggest that ectoparasite has become one potential disturbance in lobster aquaculture; therefore, preventing or curing strategies should be developed.

The impact of fresh and artificial diet on growth and survival rate of spiny lobster, Panulirus homarus reared in floating net cage

Some research found that the growth of lobster was higher when fed with fresh diet than artificial diet. Therefore, the growth of lobster that is fed with combination of fresh and artificial diets need to be observed. This study aimed to evaluate different kinds of feed and its combination on growth and survival rate of spiny lobster Panulirus homarus. This research was designed with three treatments and three replicates, namely: lobster fed with fresh diet (A), lobster fed with artificial diet (dry pellet) (B), and lobster fed with combination of fresh and artificial diets (C). Lobsters with an average weight 100.30 ±0.79 g were reared in floating net cage with dimension 2×2×2 m3 at density 40 lobsters/cage. Lobsters were fed twice a day at 08.30 am and 03.30 pm. Fresh diets that were given contained fresh fish, shrimp, crabs and mussels (3:1:1:1). The observation was conducted for 18 weeks. Results of the experiment were lobsters fed with fresh diets (A) and combination of fresh and artificial diets (C) gave higher specific growth rate (0.62±0.03 %/day and 0.61±0.03 %/day) than lobster fed with artificial diets (B) (0.33±0.01 %/day). There were not significantly differences in survival rate of lobster (p<0.05).

Growth performance and survival rate of spiny lobster Panulirus homarus (Linnaeus, 1758) with formulated feeding enriched by spinach extract

Abstract. Lubis AS, Efrizal, Syaifullah, Rusnam, Nurmiati, Puari AT. 2023. Growth performance and survival rate of spiny lobster Panulirus homarus (Linnaeus, 1758) with formulated feeding enriched by spinach extract. Biodiversitas 24: 6010-6016. In the context of spiny lobster Panulirus homarus (Linnaeus, 1758) aquaculture and marine conservation, assessing factors that influence growth and survival is critical. Spinach extract can be added as a feed additive to enhance the growth and survival rate of lobsters. This study aimed to analyze the effect of formulated feed enriched with spinach extract on spiny lobsters' growth and survival performance. A completely randomized design with five treatments and five replications: formulated feed with spinach extract 0 mg (Feed A1), 0.4 mg (Feed A2), 0.5 mg (Feed A3), 0.6 mg (Feed A4), and 0.7 mg (Feed A5) were used. The result showed that the formulated feed enriched with spinach extract had a significant effect on absolute weight, specific growth rate, length, and width of the carapace in growth performance (P<0.05) but had no significant on the survival rate and the molting frequency (P>0.05). The best result was treatment A3, adding 0.5 g of spinach extract to lobster feed with absolute weight 39.67±6.20 g, length of carapace 0.46±0.06 cm, width of carapace 0.28±0.05 cm, specific growth rate 0.38±0.06% day-1, molting frequency 1.00±0.00 times lobster-1, and survival rate 100±0.00%. The Spinach extract of 0.5 mg was the best for the survival and growth of the lobster (Duncan's test). The chemical of the feed showed that the tested feed met the nutritional needs of lobsters with a protein content of 39.74-42.60%. However, the number of amino acids in the best test feeds was still low quantity compared to several other studies, so the growth of lobsters was still slow. Based on research results, enriched 0.5 g of spinach extract to formulated feed is the best result for increasing the growth and survival rate of lobsters.

Growth at molt of sub-adult scalloped spiny lobster Panulirus homarus reared in tanks

Grow-out of lobster performed in a tank culture system offers several advantages over floating sea cage culture, particularly in the control of environmental factors. However, the growth of lobster reared in tanks need to be evaluated to determine the rearing period of lobster to achieve market size. Growth in lobster is defined as the change in size through the molting process. Therefore, this study was performed to assess differences in weight and length increment at molt of male and female sub-adult scalloped spiny lobster Panulirus homarus, as well as to determine the annual weight increment of the lobster reared in tanks. Sub-adult lobsters with an initial average weight of 226.18±20.30 g were stocked in twenty 4000-L fiber tanks at 20 lobsters/tank. Each lobster was tagged by a photographic method of the carapace to enable the identification of individual molt, as well as growth increment. Observation of molt and growth of lobster was carried out for 42 days of rearing. Growth observation for 42 days showed that the length increment between male and female lobsters was significantly different. The average length increment of the male was significantly higher (10.00 mm) than those of the female (7.93 mm) (p<0.05). However, the weight increment was not different between the sexes. The average weight increment of males and females was 18.53 g and 20.71 g, respectively (p>0.05). In terms of the annual weight increment, both sexes also had fairly similar growth, achieving 168.38 g.yr-1, on average. This study found that there was increased growth, zero growth, and declined growth at molt in lobster P. homarus.

Effect of different diets on growth performance, physiological response and behavior of spiny lobster Panulirus homarus (Linnaeus, 1758)

This study aimed to know the effect of different feedings on growth performance, physiological responses, and behavioral changes of juvenile spiny lobsters. The experimental method used a completely randomized design with three treatments and four replications. There were three different feeds used as treatment, namely: flesh mussel (K), commercial fish feed (I), and commercial shrimp feed (U). Feed is given as much as 30% of body weight, five times per day at 6:30 am, 12:00 pm, 4:00 pm, 9:00 pm, and 2:00 am. The results showed that the commercial feeding of fish (I) significantly (P&lt;0.05) increased the survival rate and biomass of spiny lobster for 54.17% and 141.7 g, respectively. While fresh mussel give better growth and stress response, but had the lowest survival rate. The results of the physiological response test of lobster were more effective in suppressing lobster stress levels than other treatments (P&lt;0.05). The behavior of juvenile spiny lobsters showed a very striking color difference and reflex impairment scores, which indicated that the vitality of the treated juveniles (I) was better than the vitality of the treatments (K) and treatment (U). This study shows that commercial fish feed (I) is recommended for maintaining spiny lobsters in the juvenile phase, although it needs further maintenance by using an appropriate feed formulation to improve the growth performance of spiny lobsters.

Genome-wide SNPs in the spiny lobster Panulirus homarus reveal a hybrid origin for its subspecies

BackgroundEvolutionary divergence and speciation often occur at a slower rate in the marine realm due to the higher potential for long-distance reproductive interaction through larval dispersal. One common evolutionary pattern in the Indo-Pacific, is divergence of populations and species at the peripheries of widely-distributed organisms. However, the evolutionary and demographic histories of such divergence are yet to be well understood. Here we address these issues by coupling genome-wide SNP data with mitochondrial DNA sequences to test the patterns of genetic divergence and possible secondary contact among geographically distant populations of the highly valuable spiny lobster Panulirus homarus species complex, distributed widely through the Indo-Pacific, from South Africa to the Marquesas Islands.ResultAfter stringent filtering, 2020 SNPs were used for population genetic and demographic analyses, revealing strong regional structure (FST = 0.148, P < 0001), superficially in accordance with previous analyses. However, detailed demographic analyses supported a much more complex evolutionary history of these populations, including a hybrid origin of a North-West Indian Ocean (NWIO) population, which has previously been discriminated morphologically, but not genetically. The best-supported demographic models suggested that the current genetic relationships among populations were due to a complex series of past divergences followed by asymmetric migration in more recent times.ConclusionOverall, this study suggests that alternating periods of marine divergence and gene flow have driven the current genetic patterns observed in this lobster and may help explain the observed wider patterns of marine species diversity in the Indo-Pacific.

Biochemical response and production performance of spiny lobster Panulirus homarus seed reared with different shelter materials

Provision of shelters during nursery rearing of the spiny lobster Panulirus homarus seed is expected to reduce stress and generate higher production performance. In the present study, three types of shelter materials viz, polyvinyl chloride (PVC) pipes, polyethylene (PE) nets and concrete blocks with three replications were used as treatments. The results showed that pipe shelter was the best among three treatments with better yield, higher survival rates and lower stress level indications. Examination of haemolymph for total cholesterol, total protein, total haemocyte count (THC) and glucose showed that pipe shelter treatment exhibited the lowest stress response compared to the other treatments. In terms of lobster weight and carapace length, the application of pipe shelters resulted in the best growth of seeds. Furthermore, the highest daily weight gain and survival rate of 1.41±0.04 and 72.67±1.53% respectively were recorded in seeds reared in pipe shelter, while the lowest values were recorded in concrete block shelter.Keywords: Glucose, Lobster, Shelter, THC, Total cholesterol, Total protein

The effects of alkalinity on production performance and biochemical responses of spiny lobster Panulirus homarus reared in recirculating aquaculture system

Spiny lobsters (Panulirus sp.) were valuable and one of the most popular Indonesian export commodities. Some approaches were made to increase the quantity and quality of cultivated spiny lobsters. Land-based mariculture with Recirculating Aquaculture System (RAS) was applied to increase lobster harvesting and optimize environmental quality by adjusting water alkalinity. This study aimed to determine the optimum level of alkalinity for spiny lobsters Panulirus homarus rearing in RAS. This study investigated the effects of applying four water alkalinity levels (Control, 125, 200, and 275 mg L-1 CaCO3) on the biochemical responses of P. homarus observed in the hemolymph in terms of Total Hemocyte Count (THC), glucose, total protein, calcium, and pH levels. Furthermore, we also studied the alkalinity effects on lobster production performance parameters in terms of body weight gain, body length, Survival Rate (SR), Specific Growth Rate (SGR), and Feed Conversion Ratio (FCR). Lobsters with an initial weight rate of 58.05±1.69 g and an initial total length rate of 115.33±1.52 mm were reared for 60 days in a recirculation system. Results of water quality parameters such as ammonia, nitrite, nitrate, dissolved oxygen, temperature, and salinity during the study were available for lobster rearing. Different alkalinity levels affected the biochemical responses and production performance of lobsters. The best alkalinity level to reared Panulirus sp. in the recirculation system during this study was 200 mg L-1 CaCO3 so that it could achieve the highest survival rate of 86.67% with SGR 0.60±0.01 % day-1.

Sound Productivity of Spiny Lobster Panulirus homarus (Linnaeus, 1758) due to Crude Oil Contamination

Anthropogenic activities have the potential to put pressure on the marine environment. Crude oil was one of the pressure that give rise to any response of the aquatic organism, such as sound. This study aimed to analyze the sound productivity of spiny lobster Panulirus homarus (Linnaeus, 1758) in waters contaminated with crude oil. Observation of lobster sound was carried out on a laboratory scale using the passive acoustic method. A hydrophone and Closed Circuit Television (CCTV) camera coupled with a decoder and personal computer used to record the movements and sounds of P. homarus during the treatment of crude oil at concentrations 1; 5; 10 and 100 mgL-1. The result showed that crude oil contamination in water was impacted the sound productivity of P. homarus. In the low concentration of crude oil (1 - 5 mgL-1), P. homarus was responded with more sound produced. Afterwar, until concentration off 10 mgL-1, the response of P homarus showed different between individuals. In the 100 mgL-1 concentration, the sound productivity of all P. homarus was decreased. Based on this study, we concluded that the sound of P. homarus has the potential as an indicator of water pollution.Keywords: Panulirus houmarus, crude oil, fish sound

Reproductive seasonality and fecundity of the spiny lobsterPanulirus homarus homarus(Linnaeus, 1758) (Decapoda: Achelata: Palinuridae) in Kenya: implications for sustainable management

AbstractThe scalloped spiny lobster Panulirus homarus homarus (Linnaeus, 1758) is one of the most commercially important lobsters exploited in Kenya. Despite its local importance and wide distribution, detailed knowledge on its reproduction in East Africa is lacking. The study reported herein sought to determine its spawning season based on seasonal variations in female gonadosomatic index (GSI), temporal distribution of ovarian maturity stages, and the proportion of ovigerous females in the monthly samples captured off Mambrui, Kenya. The study also assessed size composition, sex ratio, fecundity, and reproductive potential. A total of 2,454 lobsters were collected during the study period (January 2000-December 2001), covering a size range of 26–115 mm carapace length (CL). Neither the overall sex ratio nor the monthly sex distributions deviated significantly from the expected ratio of 1:1, except for a few months when males and females alternately dominated the samples with no discernible seasonal trends. Analysis of the cyclical changes in reproductive activity shows strong spawning seasonality in synchrony with the Northeast monsoon season in both years. Simultaneous breeding of a wide size range of females (54–90 mm CL) commenced in November and intensified over the following months until April. Outside the Northeast monsoon season, only 10 females, out of the total 517 sexually mature females sampled during the 2000 and 2001 Southeast monsoon seasons, bore eggs, and all were large individuals (&amp;gt;66 mm CL) encountered in the 2001 samples. Fecundity was positively and linearly related to female size (CL) and best described by the equation E = 10,400 CL – 472,040 (R2 = 0.929, N = 59). Estimated fecundity varied between 81,000 and 474,000 eggs per spawn in female lobsters (54 mm–91 mm CL). Female lobsters between 66 mm and 80 mm CL contributed 62% of the estimated total egg production of the population. The widespread retention of egg-bearing females in a fishery where the main fishing season falls during the spawning season, can have detrimental effects on the spawning stock abundance and egg production with increased risk of recruitment failure and stock collapse.

Lobster Fishery and aquaculture development in the North coast of Gulf of Oman: with emphasis on spiny lobster Panulirus homarus

Lobster Fishery and aquaculture development in the North coast of Gulf of Oman: with emphasis on spiny lobster Panulirus homarus

Lobster Fishery and aquaculture development in the North coast of Gulf of Oman: with emphasis on spiny lobster Panulirus homarus

Lobster Fishery and aquaculture development in the North coast of Gulf of Oman: with emphasis on spiny lobster Panulirus homarus

The effect of probiotic and prebiotic-MOS on the survival, growth and immune competence on spiny lobster Panulirus homarus culture

The use of probiotics and prebiotic to improve growth and health status of spiny lobster has been evaluated. The purpose of this study was to obtain the effect of probiotics and prebiotics for the culture of spiny lobster Panulirus homarus. The method was initiated with culturing of probiotics (4 strains) and supplemented it in a moist diets. Spiny lobster was collected from Jembrana-Bali waters with an initial body weight of 70.34 ± 4.5 g and cultured in concrete tanks with volume of 4 m3. Initial stock density for each treatment was 15 pcs / m3. The treatments tested were supplemented on moist diets with (A) probiotics, (B) probiotics and prebiotics-MOS (Mannan Oligo Sacharida) and (C) Controle (without probiotics and prebiotic) and each treatment with three replication. The results obtained that the survival rate of spiny lobster was not significantly different (P> 0.05), i.e. (A) 92.70%, (B) 93.33 (%) and (C) 93.33% respectively. However, the results of probiotics supplementation as well as a combination of probiotics and prebiotics showed growth differences compared to control (P<0.05), namely (A) 156.97 ± 6.17 g, (B) 153.75 ± 9.17 g, while (C) control 131.47 ± 7.91 g. The probiotics supplementation on moist diets could increased health status of spiny lobsters, this was expressed by target genes related to immunity (ALFHa-1, ALFHa-4, SAA, ProPO, Tgase and CP). Spiny lobster immunity increased by 2.60 to 42.7 times after challenging with MHD (Milky Haemolymph Disease). The supplementation of probiotics and prebiotics (MOS) could increase immune response by 2.10 to 25.75 times, respectively after challenging with MHD.

Growth and survival of spiny lobster, Panulirus homarus fed fresh food and formulated diet

To date, lobster aquaculture relies on fresh food for feeding; however, the availability of fresh food is limited and its excessive use causes environmental degradation. Therefore, formulated diet is required to establish sustainable lobster aquaculture. Concerning this issue, this study was carried out to assess the growth and survival of spiny lobster Panulirus homarus fed fresh food and formulated diet. The study was conducted in a completely randomized design (CRD) with 3 groups of treatments and 3 replicates for each treatment. Feeding experiment was performed in a flow-through water system using 9 fibre tanks, 4000 L in volume. Each tank was stocked with 40 lobsters, with initial weight of 78.08 ± 0.22 g. Each group of lobsters was fed with fresh food (A), formulated diet (pellet) (B) and a combination of pellet and fresh food (C). The fresh food was a mixture of fish, crabs, shrimp and small mussel (3:1:1:1). Feeding experiment was done for 15 weeks. Results of the experiment showed that the highest specific growth rate of lobster was obtained from lobsters fed with the combination of pellet and fresh food (0.52 ± 0.02 %/day) and the lowest growth was resulted from lobsters fed formulated diet (0.16 ± 0.03 %/day). In contrast, the highest survival was achieved in lobsters fed formulated diet (51.67%). Whereas the lowest survival was found in lobsters fed fresh food (10%). This study indicated that good growth of lobster was resulted from feeding with formulated diet combined with fresh food, while good survival was supported by feeding with formulated diet.

Identify and characterize the SNP markers for traceability of scallop spiny lobster Panulirus homarus (Decapoda, Palinuridae) in Vietnam

Lobster is an aquatic species of ecological and economic importance. In Vietnam, ornate spiny lobster (Panulirus ornatus) and scallop spiny lobster (P. hormatus) are among the main species of aquaculture in Vietnam. Demand for lobster products domestically and internationally is increasing, as in the US, Japan and China markets. Today, consumers are more aware of product brands, food safety and hygiene, so product traceability is essential to protect consumers and businesses. The DNA markers are widely used for commercially traded seafood traceability. Among that, Single Nucleotide Polymorphisms (SNPs) have been shown to be robust markers, and offer high reliability. EzRAD sequencing is applied to detect potential SNPs that are characteristic for P. homarus populations in Vietnam and Sri Lanka. Through 211 valid SNPs, we detected and 12 SNPS occurring in Vietnam population, and designed 8 primer pairs to amplified 80-130 bp SNPs products. PCR optimization allows us to select 2 SNPs serving the traceability of Vietnamese P. homarus. Further need to more population sampling, and whole genome sequencing in order to develop SNPs panel to seeking the origin of lobster seafood products.

Improving Survival of Juvenile Scalloped Spiny Lobster (Panulirus homarus) and Crucifix Crab (Charybdis feriatus) Using Shelter and Live Prey.

Simple SummaryFighting with each other is a major problem in lobster and crab aquaculture. Reducing the fighting behavior of lobsters and crabs can improve survival during the culturing process. Juvenile lobsters and crabs were both cultured under different shelters (seaweed and cotton filter) and live prey conditions. Groups with shelter and co-culturing with live prey showed a better survival rate for both juvenile lobsters and crabs. Although providing shelter is currently the main method for reducing agonistic behavior, it must be continually altered as the lobsters and crabs grow. Live prey can grow and attract lobsters and crabs to hunt them, and live prey can be supplemented at any time. They can also be used as an additional source of income during the harvest season.Cannibalism is a major problem in lobster and crab aquaculture. Reducing the aggressive characteristics of lobsters and crabs can improve survival during the culturing process. In this study, juvenile scalloped spiny lobsters (Panulirus homarus) and crucifix crabs (Charybdis feriatus) were both cultured under different shelter and live prey conditions. Groups with shelter (seaweed and cotton filter) showed a better survival rate than the control group (no shelter; p < 0.05) for both Pa. homarus and Char. feriatus. Co-culturing with live prey (Litopenaeus vannamei) significantly benefited the juveniles of Pa. homarus and visibly increased the survival of juvenile Char. feriatus. Although providing shelter is currently the main method for reducing agonistic behavior, it must be continually altered as the lobsters and crabs grow. Live prey can grow and attract lobsters and crabs to hunt them, and live prey can be supplemented at any time. They can also be used as an additional source of income during the harvest season.

Genetic structure and life history are key factors in species distribution models of spiny lobsters.

AimWe incorporated genetic structure and life history phase in species distribution models (SDMs) constructed for a widespread spiny lobster, to reveal local adaptations specific to individual subspecies and predict future range shifts under the RCP 8.5 climate change scenario.LocationIndo‐West Pacific.MethodsMaxEnt was used to construct present‐day SDMs for the spiny lobster Panulirus homarus and individually for the three genetically distinct subspecies of which it comprises. SDMs incorporated both sea surface and benthic (seafloor) climate layers to recreate discrete influences of these habitats during the drifting larval and benthic juvenile and adult life history phases. Principle component analysis (PCA) was used to infer environmental variables to which individual subspecies were adapted. SDM projections of present‐day habitat suitability were compared with predictions for the year 2,100, under the RCP 8.5 climate change scenario.ResultsIn the PCA, salinity best explained P. h. megasculptus habitat suitability, compared with current velocity in P. h. rubellus and sea surface temperature in P. h. homarus. Drifting and benthic life history phases were adapted to different combinations of sea surface and benthic environmental variables considered. Highly suitable habitats for benthic phases were spatially enveloped within more extensive sea surface habitats suitable for drifting larvae. SDMs predicted that present‐day highly suitable habitats for P. homarus will decrease by the year 2,100.Main conclusionsIncorporating genetic structure in SDMs showed that individual spiny lobster subspecies had unique adaptations, which could not be resolved in species‐level models. The use of sea surface and benthic climate layers revealed the relative importance of environmental variables during drifting and benthic life history phases. SDMs that included genetic structure and life history were more informative in predictive models of climate change effects.

Molecular cloning, characterization and expression analysis of the ecdysone receptor from the spiny lobster Panulirus homarus (Linnaeus, 1758) (Decapoda, Palinuridae)

Abstract The ecdysone receptor (EcR) is a crucial nuclear transcription factor that participates in ecdysteroid signalling. In this study, cDNA of EcR in Panulirus homarus (Linnaeus, 1758) (PhEcR) was cloned and characterized. PhEcR cDNA was 3141 bp, in which a 12 bp insert/deletion splice variant region in the hinge domain was identified. PhEcR mRNA presented the most abundant expression in the ovary. PhEcR mRNA expression was rapidly upregulated in the premoult stage and downregulated in the ecdysis stage. PhEcR mRNA maintained a relatively high expression level from egg-nauplius stage to embryo stage with compound eye pigments formed. The transcript levels of PhEcR in muscle were up-regulated on the 5th and 10th day after antenna ablation. These data suggest that PhEcR may not only play a vital role in the ecdysteroid signalling, but also have relation to embryonic development and limb regeneration.

THE OCCURRENCE AND SEQUENCE ANALYSIS OF MILKY HEMOLYMPH DISEASE IN LOBSTER PANULIRUS HOMARUS FROM DIFFERENT LOCATIONS IN INDONESIA

Among the high significance diseases in spiny lobster farming, Milky Hemolymph Disease of Spiny Lobster (MHD-SL) is considered as the most devastating disease which caused in mortality up to 80 % and morbidity to 100%. Investigations of this disease were mostly performed for farmed lobster and no observation was conducted for wild lobster. This study was carried out first, to investigate milky hemolymph disease occurrence both in wild and farmed spiny lobster Panulirus homarus from different locations by PCR analysis. Second, to perform nucleotide sequence analysis in order to identify, and to describe relationship of the milky disease agent obtained in this study with the disease agent from several geographical regions by phylogenetic analysis. Adult farmed lobsters were collected from Lombok, Pangandaran and Pegametan, while wild lobsters were obtained from Jembrana, Lombok, and Banyuwangi coastal areas. One farmed lobster from Pegametan and two farmed lobsters from Lombok were infected with the milky disease. Nucleotide sequence analysis demonstrated that the causative agent of milky disease obtained in this study (MHD-1, 2, and 3) exhibited 99% homologous nucleotide sequence with milky disease agent from Vietnam that was uncultured Rickettsia-like Bacteria (RLB). As a consequence, further work is needed most importantly on how to cultivate milky disease agent in order to find proper methods to alleviate milky disease problems. This paper is the first report on phylogenetic analysis of milky disease from Indonesia that pointed out a closed relationship between milky disease in the present study and from Vietnam, Madagascar, Mozambique and Tanzania.

Between the current and the coast: genetic connectivity in the spiny lobster Panulirus homarus rubellus, despite potential barriers to gene flow

The spiny lobster Panulirus homarus rubellus is endemic to the Southwest Indian Ocean, where it inhabits a narrow continental shelf between an exposed coast and the upper reaches of the strong western-boundary Agulhas Current. Long-lived phyllosoma larvae released in this dynamic ocean environment have an uncertain fate—they can be retained over the shelf by sub-mesoscale processes, dispersed downstream along the coast or across the Mozambique Channel, or become entrained in the Agulhas Current, and presumably lost. To assess gene flow and population genetic structure, we analyzed mitochondrial cytochrome oxidase subunit 1 and hypervariable control region sequences, and 19 nuclear microsatellite loci obtained from lobsters collected at nine sites in eastern South Africa, Mozambique and southeast Madagascar. Clustering analyses confirmed genetic connectivity among all populations, and gene flow patterns supported the hypothesis that nearshore processes, such as lee eddies and counter currents, retain some phyllosomas over the shelf; whereas, net gene flow direction was moderate towards the southwest. The Mozambique Channel did not impede contemporary gene flow from Madagascar to the African shelf, but return gene flow was rare. Different marker types showed contrasting gene flow patterns during contemporary and evolutionary periods, when Pleistocene glacial/interglacial cycles would have affected sea level, ocean currents and dispersal patterns. Despite genetic connectivity and the importance of local recruitment, recent gene flow suggests an ancillary source/sink dynamic concordant with the prevailing southwesterly direction of boundary currents at the shelf-edge—a factor to consider in regional fisheries and conservation strategies.