Plectropomus Areolatus Research Articles

Spawning of tiger grouper Epinephelus fuscoguttatus and squaretail coralgrouper Plectropomus areolatus in sea cages and onshore tanks in Andaman and Nicobar Islands, India

The broodstock of two grouper species, tiger grouper Epinephelus fuscoguttatus and squaretail coralgrouper Plectropomus areolatus, were maintained in sea cages near Rutland Island, Andaman and Nicobar Islands, India, and their spawning performance was monitored from June 2007 to December 2010. E. fuscoguttatus generally spawned monthly in association with the new moon phase, for 8–9months each year. Each year, they underwent a 3- to 4-month refractory period between February and June then recommenced spawning in May–July. P. areolatus showed a different spawning pattern to E. fuscoguttatus, spawning for less than 6months each year, also in association with the new moon, and demonstrating much longer refractory periods (up to 15months) than E. fuscoguttatus. Analysis of temperature data from the sea cage site showed that water temperature was significantly lower during spawning events than during comparable non-spawning periods. We postulate that one factor inhibiting spawning is higher water temperatures exceeding the upper thermal inhibitory limit for both grouper species during the hotter months of the year. Selected broodstock fish of both species were also maintained in onshore tanks fitted with recirculating filtration systems, but the spawning performance of both grouper species in the onshore tanks was inferior to broodstock held in the sea cages. E. fuscoguttatus maintained in onshore tanks spawned during only 5months of the 42-month study period, whereas E. fuscoguttatus held in the sea cages spawned during 29months over the same time frame. P. areolatus held in onshore tanks over the same period did not spawn, whereas P. areolatus held in sea cages spawned during 16months out of the 42-month study period.

Bucephalidae (Platyhelminthes: Digenea) of Plectropomus (Serranidae: Epinephelinae) in the tropical Pacific.

We examined four species of Plectropomus Oken, 1817 (Serranidae: Epinephelinae), Plectropomus areolatus (Rüppell), Plectropomus laevis (Lacepède), Plectropomus leopardus (Lacepède) and Plectropomus maculatus (Bloch) from sites off Heron Island and Lizard Island on the Great Barrier Reef, Australia (GBR), and the Gambier Islands, French Polynesia. Three new species of Neidhartia Nagaty, 1937, five new species of Prosorhynchus Odhner, 1905, and one previously described species, Prosorhynchus freitasi Nagaty, 1937, are characterised. The three species of Neidhartia, Neidhartia haywardi n. sp., Neidhartia plectropomi n. sp. and Neidhartia tyleri n. sp. are readily distinguishable morphologically. Two of the six species of Prosorhynchus (Prosorhynchus lesteri n. sp. and Prosorhynchus wrightae n. sp.) are easily distinguished from their other congeners by morphology but the other four species (P. freitasi, Prosorhynchus heronensis n. sp., Prosorhynchus munozae n. sp. and Prosorhynchus plectropomi n. sp.) are generally similar in morphology and were only distinguished initially by comparing their ITS2 rRNA sequences. Three additional taxa, one from the GBR and two from French Polynesia, were recognised as distinct on the basis that their ITS2 rRNA sequences differed from those of the new taxa described here; these species remain unnamed for the present. Inter-specific divergence observed within these genera in the ITS2 rRNA ranged from 10 to 42 base pairs (4-16%) for species of Neidhartia and 2-57 base pairs (3-21%) for species of Prosorhynchus. Inter-generic divergences were 42-55 base pairs (17-21%). No intraspecific variation in the ITS2 rRNA region was observed for any of the six species for which multiple sequence replicates were obtained. Phylogenetic analysis of 12 operational taxa from Plectropomus together with sequences of three other species from epinepheline serranids demonstrated that Neidhartia and Prosorhynchus were reciprocally monophyletic with the exception that P. wrightae n. sp. fell either within or basal to the Neidhartia species. The richness of bucephalids in species of Plectropomus appears to be exceptional within the Serranidae relative to that observed in other serranid genera in the tropical Indo-West Pacific.

Reproductive biology of squaretail coralgrouper Plectropomus areolatus using age‐based techniques

The squaretail coralgrouper Plectropomus areolatus was identified as a fast-growing, early maturing and relatively short-lived aggregation-spawning epinephelid. Examinations of sectioned otoliths found females and males first maturing at 2 and 3 years, respectively, suggesting protogynous hermaphroditism; however, no transitionals were observed in samples. Age distribution for the two sexes was similar and both were represented in the oldest age class; however, significant sex-specific differences in size-at-age were identified. Both sexes fully recruit into the fishery at age 4 years and reach 90% of asymptotic length by age 3 years. Underwater visual assessments, combined with the gonado-somatic indices, revealed a 5 month reproductive season, with interannual variability observed in the month of highest density within the spawning aggregation. Catch restrictions on adults during spawning times and at reproductive sites, combined with gear-based management and enhanced enforcement, are recommended to maintain spawning stocks. Based on the available evidence, the sexual pattern for this species is unresolved.

Dispersal of Grouper Larvae Drives Local Resource Sharing in a Coral Reef Fishery

In many tropical nations, fisheries management requires a community-based approach because small customary marine tenure areas define the spatial scale of management [1]. However, the fate of larvae originating from a community's tenure is unknown, and thus the degree to which a community can expect their management actions to replenish the fisheries within their tenure is unclear [2, 3]. Furthermore, whether and how much larval dispersal links tenure areas can provide a strong basis for cooperative management [4, 5]. Using genetic parentage analysis, we measured larval dispersal from a single, managed spawning aggregation of squaretail coral grouper (Plectropomus areolatus) and determined its contribution to fisheries replenishment within five community tenure areas up to 33km from the aggregation at Manus Island, Papua New Guinea. Within the community tenure area containing the aggregation, 17%-25% of juveniles were produced by the aggregation. In four adjacent tenure areas, 6%-17% of juveniles were from the aggregation. Larval dispersal kernels predict that 50% of larvae settled within 14km of the aggregation. These results strongly suggest that both local and cooperative management actions can provide fisheries benefits to communities over small spatial scales.

Complete mitochondrial genome of squaretail coralgrouper Plectropomus areolatus (Perciformes, Epinephelidae)

The complete mitochondrial genome (mitogenome) sequence of squaretail coralgrouper Plectropomus areolatus was determined with long PCR approach. The genome was 16,770 bp in length and contained 13 protein-coding genes, 22 transfer RNAs (tRNAs), 2 ribosomal RNAs (rRNAs), and 2 non-coding regions, with the gene content and order being similar to most other teleosts. The overall base composition of the mitogenome was estimated to be 28.81% A, 27.63% T, 27.24% C, and 16.33% G, with a high AT content of 56.44%, indicating an obvious anti-guanine bias commonly observed in fishes. It shared 90.7%, 78.8%, and 78.7% mitogenome sequence with Plectropomus leopardus, Epinephelus moara, and Epinephelus coioides, respectively.

Fishing in the dark-local knowledge, night spearfishing and spawning aggregations in the Western Solomon Islands

Within the marine conservation community there is considerable interest in combining local knowledge and science to achieve management objectives. Yet there remain few studies which have examined the merits and caveats of local knowledge, or shown how combining both knowledge systems has resulted in better management outcomes. This study outlines collaborative efforts to conserve fish spawning aggregations (FSAs) in Roviana Lagoon, Western Solomon Islands. Baseline information on FSAs was obtained through local knowledge and spearfishing creel surveys. This information provided the starting point for establishing a 2-year community-based underwater monitoring program at the largest known FSA in Roviana Lagoon, where the brown-marbled grouper (Epinephelus fuscoguttatus), camouflage grouper (Epinephelus polyphekadion) and squaretail coralgrouper (Plectropomus areolatus) co-aggregate. This participatory research shows that local knowledge on FSAs is utilised to maximise returns from fishing, with spearfishermen targeting aggregations at night during the lunar periods when abundances peak. Because of its shallow distribution P. areolatus is the most vulnerable of the three groupers to nighttime spearfishing, with two fishermen capable of removing 15–30% of the total spawning biomass in two nights. Underwater monitoring demonstrates that while fishermen provided accurate information on many aspects of FSAs, their knowledge on spawning seasons was inaccurate for the FSA reported on here. Peak aggregations occurred from December to April each year, which differs from the traditionally recognised grouper season of October to January. A combination of local knowledge and science was used to develop appropriate management measures for this FSA, with the aggregation declared a community-based marine protected area (MPA) in 2006.

Community-based conservation results in the recovery of reef fish spawning aggregations in the Coral Triangle

In the Coral Triangle community-based marine protected areas (MPAs) are being established at a prolific rate. Their establishment can benefit both fisheries and biodiversity, and they provide both a socially and economically acceptable means of managing coral reefs in developing nations. However, because such MPAs are typically small (usually <0.5 km 2), they will rarely provide protection to large mobile fishes. An exception to this limitation may exist when community-based MPAs are established to protect small sites where vital processes occur, such as fish spawning aggregations (FSAs). To test the effectiveness of small (0.1–0.2 km 2) MPAs for protecting FSAs, we monitored three FSA sites where brown-marbled grouper ( Epinephelus fuscoguttatus), camouflage grouper ( Epinephelus polyphekadion) and squaretail coralgrouper ( Plectropomus areolatus) aggregate to spawn. Sites were monitored during peak reproductive periods (several days prior to each new moon) between January 2005 and November 2009. All three sites are located in New Ireland Province, Papua New Guinea, and had been exploited for decades, but in 2004 two sites were protected by the establishment of community-based MPAs. The third site continued to be exploited. Over the monitoring period densities of E. fuscoguttatus and E. polyphekadion increased at both MPAs, but not at the site that remained open to fishing. At one MPA the densities of E. polyphekadion increased tenfold. Our findings demonstrate that community-based MPAs that are appropriately designed and adequately enforced can lead to the recovery of populations of vulnerable species that aggregate to spawn.

Spatial and temporal characteristics of grouper spawning aggregations in marine protected areas in Palau, western Micronesia

In Palau, Ngerumekaol and Ebiil Channels are spawning aggregation sites that have been protected from fishing since 1976 and 2000, respectively. Groupers and other targeted fisheries species were monitored monthly over a 1.5 year period at these two spawning aggregations and two nearby exploited reference sites where grouper formerly aggregated to spawn. At the protected aggregation sites, three grouper species ( Plectropomus areolatus, Epinephelus polyphekadion, and Epinephelus fuscoguttatus) accounted for 78% of the abundance and 85% of the biomass of all resource species surveyed but comprised <1% of the total abundance and biomass at reference sites not protected from fishing that formally harbored spawning aggregations. Abundance and biomass of grouper species pooled were 54% and 72% higher, respectively, at Ngerumekaol compared to Ebiil. Comparisons with data from the same locations in 1995–1996 showed order of magnitude declines in abundance of E. polyphekadion at both locations. The lower numbers of E. fuscoguttatus and the near absence of E. polyphekadion at Ebiil may reflect the effects of previous and current overexploitation.

Do Not Stop: The Importance of Seamless Monitoring and Enforcement in an Indonesian Marine Protected Area

The harvesting of groupers (Serranidae) in Indonesia for the live reef food fish trade (LRFFT) has been ongoing since the late 1980s. Eight sites in Komodo National Park that included two fish spawning aggregation (FSA) sites were monitored for groupers and humphead wrasse,Cheilinus undulatus, from 1998 to 2003 and from 2005 to 2008 to examine temporal changes in abundance and assess the effectiveness of conservation and management efforts. Monitoring identified FSA sites for squaretail coralgrouper,Plectropomus areolatus, and brown-marbled grouper,Epinephelus fuscoguttatus. Both species formed aggregations before and during full moon from September to December, prior to lapses in monitoring (2003–2005) and in enforcement (2004-2005). Following these lapses, data reveal substantial declines inP. areolatusabundance and the apparent extirpation of one aggregation at one site. Other non-aggregating species targeted by the LRFFT showed similar declines at three of eight monitored sites. This paper highlights the impact of FSA fishing and the need for a seamless monitoring and enforcement protocol in areas where aggregation fishing pressure is high. Within Komodo National Park, local fishers, particularly those operating on behalf of the LRFFT, pose a serious threat to population persistence of species targeted by this trade.

Grouper (Pisces: Serranidae) relative abundance and diversity on the west coast of India

We used timed underwater visual censuses to study grouper relative abundance and diversity on the west coast of India. Eighteen grouper species were observed in these surveys, including two new records for the west coast of India, Aethaloperca rogaa and Plectropomus areolatus. Cephalopholis formosa and Epinephelus faveatus were the most abundant species observed with the latter more numerous on inshore than offshore rocky reefs. Ecological and distributional notes are given for the species observed.

Home range estimates for squaretail coralgrouper, Plectropomus areolatus (Rüppell 1830)

The aim of the study was to estimate home range areas and distance of movement away from a squaretail coralgrouper (Plectropomus areolatus) spawning aggregation site located within a small-scale 1.5 km2 Marine Protected Area (MPA) in Pohnpei, Micronesia. Fifteen P. areolatus were acoustically tagged and re-located within a ca. 50 km2 search area over a 4-month period that included reproductive and non-reproductive months. All relocated fish were found in areas of moderate to high coral cover either on the fore reef or inside the lagoon in home ranges of 0.048 ± 0.018 km2 (μ ± S.E.). Variability in home range area (0.004–0.12 km2) and distance of movement from aggregation sites following spawning (0.02–23.0 km; 5.3 ± 3.6 km, μ ± S.E.) was observed, but did not appear to be sex specific. Five of the six relocated individuals were found within 0.02–6.1 km of the aggregation. This evidence and that from recent tag-recapture studies of epinephelids suggest that a substantial proportion of individual P. areolatus spawning populations reside within close proximity to their respective aggregation sites. Reproductive populations could be protected by MPAs of moderate scale (10 s of km2) that include aggregation sites, migratory corridors and adjacent home range habitats.

Ciguatera incidence and fish toxicity in Okinawa, Japan

Okinawa being located in the subtropical region has the highest incidence of ciguatera in Japan. Officially, 33 outbreaks involving 103 patients have been reported between 1997 and 2006. The implicated species were Variola louti, Lutjanus bohar, Lutjanus monostigma, Epinephelus fuscoguttatus, unidentified Lutjanus sp., Plectropomus areolatus, Oplegnathus punctatus, Epinephelus polyphekadion, Caranx ignobilis and moray eel. Toxicities of the leftover meals, as determined by mouse bioassays, ranged from 0.025 to 0.8 MU/g or above (equivalent to 0.175–5.6 ng CTX1B/g). We collected 612 specimens of fish belonging to L. monostigma, L. bohar, Lutjanus argentimaculatus, Lutjanus russellii, V. louti, Variola albimarginata, and E. fuscoguttatus from the coasts around Okinawa and examined the toxicity of the flesh by the mouse bioassay. The rate of toxic fish was as follows: L. monostigma: 32.3%, L. bohar: 11.9%, V. louti: 14.3%, E. fuscoguttatus: 20.8%. Only one out of 36 samples of V. albimarginata and two of 74 samples of L. russellii were found toxic. None of the 35 samples of L. argentimaculatus was toxic. Nor the L. bohar samples weighing less than 4 kg were toxic. In all toxic samples, CTX1B was detected by LC/MS analysis but CTX3C and 51-hydroxyCTX3C were not.

Population biology of coral trout species in eastern Torres Strait: Implications for fishery management

Coral trout ( Plectropomus spp.) are the main target species for commercial fishers in the eastern Torres Strait Reef Line Fishery (ETS RLF). The four species of coral trout known to occur in Torres Strait: Plectropomus leopardus, Plectropomus maculatus, Plectropomus areolatus and Plectropomus laevis are currently managed as a single species in Torres Strait, as there is no species-specific biological information available for the region which could be used to assess whether species differ in their response to fishing pressure. The aim of our study was to determine whether it is appropriate (biologically) to manage coral trout in the ETS RLF as a single species group or whether different management arrangements are required for some species. We used catch data and biological data from samples collected by commercial fishers to examine the distribution within Torres Strait and estimate a range of biological parameters for P. leopardus, P. maculatus and P. areolatus. Insufficient P. laevis samples were collected to reliably examine this species. Results indicated that the population biology, particularly the reproductive biology, of P. areolatus was substantially different to both P. leopardus and P. maculatus. Although it is difficult to predict the response to fishing, P. areolatus may be more vulnerable to fishing than P. leopardus and P. maculatus, due to the larger size at sex change observed for this species and the very low proportion of males protected by the current minimum size limit. Therefore, while the common management arrangements for P. leopardus and P. maculatus appear to be adequate for these species, separate management arrangements are needed for the sustainable harvest of P. areolatus populations in the ETS. Specifically, we recommend the introduction of a maximum size limit for P. areolatus, in addition to the current minimum size limit, which may allow a proportion of males some protection from fishing.

Identification of nursery habitats for commercially valuable humphead wrasse Cheilinus undulatus and large groupers (Pisces: Serranidae) in Palau

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 332:189-199 (2007) - doi:10.3354/meps332189 Identification of nursery habitats for commercially valuable humphead wrasse Cheilinus undulatus and large groupers (Pisces: Serranidae) in Palau Mark Tupper1,2,* 1The WorldFish Center, PO Box 500 GPO, 10670 Penang, Malaysia 2Marine Lab, University of Guam, UOG Station, Mangilao, Guam 96923, USA *Email: m.tupper@cgiar.org ABSTRACT: In recent years there has been increasing interest in conserving fish habitats. However, fish–habitat associations, particularly nursery habitat for early juvenile stages, are poorly known for most reef fishes. Using mark–recapture techniques, I examined among-habitat variation in settlement, post-settlement growth, and persistence, and movement in 3 large, vulnerable, and commercially important reef fishes: the humphead wrasse Cheilinus undulatus, the squaretail coralgrouper Plectropomus areolatus, and the camouflage grouper Epinephelus polyphekadion. Both the humphead wrasse and the coralgrouper appeared to utilize specific nursery habitats. Settlement, growth, and persistence of humphead wrasse were highest in branching coral structures mixed with bushy macroalgae (BCMA). Of all tagged C. undulatus recaptured in intermediate or adult habitats, 80% were tagged post-settlement in BCMA. Early juvenile P. areolatus were found almost exclusively in coral rubble habitats on the slopes of tidal channels, at a narrow depth range of 5 to 7 m. This dependence on one habitat type could render this species vulnerable to shipping or dredging operations or other forms of coastal development. E. polyphekadion appeared to be a habitat generalist, and no specific nursery habitat could be identified. In summary, spatial management (e.g. implementation of marine protected areas) should prioritize habitats for conservation according to their value as essential nursery or spawning habitats for target species needing protection. KEY WORDS: Fish habitat · Nursery areas · Grouper · Humphead wrasse Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 332. Online publication date: March 05, 2007 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2007 Inter-Research.

Aggregations of Plectropomus areolatus and Epinephelus fuscoguttatus (groupers, Serranidae) in the Komodo National Park, Indonesia: Monitoring and Implications for Management

We identify fishery management implications from a long-term monitoring program focusing on spawning aggregations of high valued reef fish in Komodo National Park (KNP), Eastern Indonesia. Management objectives of KNP are not only to protect biodiversity, but also to conserve spawning stocks of high-valued commercial species for the replenishment of surrounding fishing grounds. We monitored two sites twice monthly over five years for two species of grouper, Epinephelus fuscoguttatus and Plectropomus areolatus. One site had an aggregation of both E. fuscoguttatus and P. areolatus, whereas the other site contained an aggregation of P. areolatus only. Over the five years monitoring period, aggregations typically formed during each full moon between September and February. Additionally, P. areolatus occasionally aggregated during new moons between April and July. We observed spawning only once, but because formation of aggregations were correlated to a higher incidence of behavior and signs indicative of reproduction and because most fish present were adults, it is likely that the formation of aggregations was associated with spawning. Over the five years monitoring period there was a reduction in mean fish size of up to 8 cm for P. areolatus, and a reduction in numbers of aggregating E. fuscoguttatus. Despite limited protection initiated in 2001, both sites are still heavily fished by local artisanal fishers. Because the observed reductions in size and in numbers could be caused by fishing pressure, managers should follow the precautionary principle by putting additional protective management in place. Since both species are relatively long-lived, at least five years of continued monitoring may be necessary to determine the outcome of management intervention. The variability in timing of aggregation in respect to season and moon phase in P. areolatus indicates that long-term monitoring must cover the entire year and both moon phases.

Study of an outbreak of ciguatera fish poisoning in Hong Kong

Ciguatera fish poisoning (CFP) has been a significant and increasing public health problem in Hong Kong since 1980s. With growing demand for imported live coral fishes, the number of people who suffered from this disease has also been increasing. An outbreak of CFP in 2004 was the second most prominent in record as compared with the most significant one that occurred in 1998. In 2004, out of a total of 823 reported food poisoning outbreaks involving 3159 persons, 65 incidents (7.9%) affecting 247 people (7.8%) were attributed to CFP. Validated mouse bioassay analysis of surveillance samples revealed that seven samples (13%) were confirmed to be contaminated with ciguatoxins (CTXs). Typical symptoms of CTXs were found in mice injected with 20 mg of fish extracts. The causative fishes included Cheilinus undulatus, Epinephelus coioides, Plectropomus areolatus, and Plectropomus leopardus. Most of these CTX-positive samples analyzed had only trace amounts of CTXs in their extract, except a C. undulatus sample which contained a mice lethal dose (2.5 MU/20 mg ether extract). This fish species was also the major origin of coral fish that caused clusters of CFP in the last quarter of 2004. Cigua-Check ® analysis of 20 flesh grains from seven CTX-positive fishes, previously confirmed as CTX-positive samples by mouse bioassay, showed that 50% of flesh grains were CTX contaminated.

Grouper and Napoleon Wrasse ecology in Laamu Atoll, Republic of Maldives: Part 2. Timing, location, and characteristics of spawning aggregations

The reproductive ecology of five species of grouper and the Napoleon wrasse was studied March-June, 1998 in Laamu Atoll, Republic of Maldives. Research focused on identifying the timing, location, and characteristics of spawning aggregations in this atoll. Timed surveys were used to assess fish abundance and size distribution in Mundoo Channel, which is one of seven channels connecting Laamu Atoll's inner atoll lagoon to the open ocean. Through a pilot study, and later confirmed in the main study, it was concluded that observations could be conducted and compared over different times of the day, tidal cycles, current speeds, and among observers. A spawning aggregation of Plectropomus areolatus, defined as a three-fold abundance increase over ambient levels, was recorded in Mundoo Channel during the new moon in April, 1998. Data collected during the pilot study suggested that an aggregation occurred in this channel during March, 1998. Courtship behavior for this species was recorded during these two months. Data suggested that P. laevis spawned during this time period as well. Spawning was never observed, but abundance increases and courtship behavior indicate that spawning occurred during this time.

Induced Spawning of Two Western Tropical Pacific Groupers, Plectropomus areolatus and Epinephelus fuscoguttatus, in Palau

In May and June 1991, 10 squaretail coral trout (Plectropomus areolatus) females ovulated 34-36 hours after the first of two intramuscular injections of hwnan chorionic gonadotrow pin (HCG), producing 4,001,000 eggs; four fish later released an additional 1,792,000 eggs, and another 1,630,000 eggs were found in the holding tank. Five females ovulated naturally several hours after capture (about 12 hours before the new moon in June), producing 856,000 eggs. In June, three brown-marbled grouper (Epinephelus fuscoguttatus) females ovulated 37w39 hours after the first of one or two HCG injections, producing 5,035,000 eggs, with another 42,000 found in the tank. Coral trout egg diameter range was 687w8l4 µm (mean 754 µm) and oil globule diameter range 170-257 µm (mean 213 µm). Brown-marbled grouper egg diameter range was 743-826 µm (mean 789 µm) and oil globule diameter range 187-251 µm (mean 215 µm). In most cases, fertilization and hatching rates were high. Induced spawns produced 1,755,000 coral trout and 3,791,000 brown-marbled grouper hatchlings.