Siganus Guttatus Research Articles

Ciguatera in the Philippines: Examining Reef Fish Vectors and Its Causative Benthic Dinoflagellates in Visayan and Sibuyan Seas

Ciguatera Fish Poisoning (CFP) is primarily caused by ingesting reef fishes contaminated with ciguatoxins (CTX) produced by the Gambierdiscus species. The unpredictability of this type of food poisoning poses risks to public health and adversely affecting the fish trade industry. This study aimed to provide useful information on ciguatera in the Philippines. Different reef fish species and host-macroalgae for benthic dinoflagellates were collected in Visayan and Sibuyan Seas. Ciguatoxins were extracted from reef fish samples, and toxicity was determined qualitatively using mouse bioassay. Meanwhile, cell density estimation of toxic benthic dinoflagellates isolated from the host-macroalgae was done through microscopy. It was observed that 4.46% of the total reef fish samples were positive with ciguatoxins. Spatially, Carles, Iloilo in Visayan sea had the highest number of toxic specimens belonging to Epinephelus merra, Lethrinus lentjan, Lutjanus campechanus, Scarus quoyi, Siganus guttatus, and Sphyraena barracuda. Based on data gathered from three sampling sites, fish toxin occurrence is observed to be site-specific. Geographical conditions affect the frequency of toxic samples. Moreover, fish weight is not a good predictor of fish toxicity. For toxic benthic dinoflagellates, Gambierdiscus spp. were observed to have the lowest cell density count among other dinoflagellates averaging 7-115 cells per 100 g macroalgae. On the other hand, Ostreopsis spp. had the highest average cell density of 118-1,455 cells per 100 g macroalgae, followed by Prorocentrum spp. (207-594 cells per 100 g macroalgae). Fish toxicity is directly proportional to the occurrence of benthic dinoflagellates in areas as seen during dry season. Monitoring and management of CFP on identified reef fish vectors and its causative benthic dinoflagellates in the area are necessary to promote food safety and fair trade practice.

Biological analysis of adult rabbitfish (Siganus guttatus bloch, 1787) in seagrass and coral reef ecosystems at laikang bay, takalar regency

The rabbitfish (Siganus guttatus) is a fish which has a high economic value also became one of the most popular types of fish consumed by the Takalar people up to Makassar City. The high market demand makes the effort to catch fishermen become greater so that the pressure on this species also becomes greater. therefore this research is needed to provide information in the preparation of comprehensive and systematic management strategies by policy makers to maintain the sustainability and sustainability of Siganus guttatus resources in the waters. The scope of this research includes information on rabbitfish habitat, abundance, feeding habits, sex ratio, and gonad maturity level (GML), as well as to compare the distribution pattern, gut content and GML in seagrass and coral reef ecosystems. This research was carried out from March to June 2017 in Laikang Bay, Takalar Regency, South Sulawesi Province, Indonesia. Rabbitfish samples (N = 336) were collected, comprising 293 males and 43 females with the size ranges of 11.2 – 35.9 cm and 8.4 – 35.4 cm, respectively. GML ranged from I – V. The GML in coral reef ecosystem was generally higher than in seagrass. The GML and number of individuals from the coral reef ecosystem were: GML I (133 fish), GML II (84 fish), GML III (30 fish), GML IV (12 fish), GML V (8 fish); whereas from seagrass ecosystem, GML I (12 fish), GML II (11 fish), GML III (2 fish). Gut content analysis found 36 phytoplankton species; the taxa comprising the highest percentages were Thallassiothrix sp. (69.24%) in the coral reef ecosystem and Oscillatoria sp. (26.34 %) in seagrass.

Seasonal changes in three indices of gonadal maturation in male golden rabbitfish (Siganus guttatus): implications for artificial propagation.

Monthly changes of hepatosomatic index (HSI), gonadosomatic index (GSI), and plasma testosterone (T) levels in the reproductive season of male golden rabbitfish (Siganus guttatus) in captivity were investigated by sampling the liver, testis, and blood. HSI and GSI were estimated as percentage of relative weight of liver and testis to total body weight, respectively. Plasma T levels were measured using enzyme immune assay (EIA). Fragments of the testis were embedded in paraffin, cut to 5μm thickness, and stained with Harris' hematoxylin and eosin. The results included seasonal changes in HSI, GSI, T, and testicular stages. The plasma T levels were observed high at spermation stage and during February-March and May-June. The values of HSI were monthly fluctuations, but no significant differences between testicular stages were observed. The GSI values continuously exhibited a significant increase from December to April and maintained at high levels until June. GSI continuously increased from stage II (immature testis) to stage V (spawning testis). There was correlation between GSI and testicular stages. Histological sections showed that male golden rabbitfish are multiple spawners and spawning season starts from March to June. These results contribute to further understanding of reproductive biology in golden rabbitfish, which can be implicated for artificial propagation.

Effects of human chorionic gonadotropin and gonadotropin releasing hormone analogue on plasma steroid hormones and spawning performances in golden rabbitfish Siganus guttatus

In this experiment, golden rabbitfish (Siganus guttatus) were allocated between three treatment groups. The fish were injected with saline, human chorionic gonadotropin (hCG) and D-Ala6, Pro9-Net-mGnRH. After injection, in 6 hr intervals, blood plasma samples were collected for steroid hormone (testosterone [T] in males and estradiol-17β [E2] in females) using enzyme immune assay (EIA). In male fish, T levels significantly increased and reached 170 and 650 pg/ml for hCG and D-Ala6, Pro9-Net-mGnRH treatments, respectively. Then T levels slightly decreased until 24 hr post injection. There were no significant changes of T levels in saline treatment. In female fish, we found significant changes in E2 levels at 2,567 and 524 pg/ml at 12 hr post injection in hCG and D-Ala6, Pro9-Net-mGnRH treatments, respectively. No significant differences of E2 levels were observed in saline group. In the second experiment, we injected 100 golden rabbitfish with both hCG and D-Ala6, Pro9-Net-mGnRH. Fish spawned successfully when hCG and D-Ala6, Pro9-Net-mGnRH were given individually and in combination. Latency periods were between 46–64 hr with an average fertilization rate of 70%–90% and hatching rate of 56%–74%. The embryonic duration was 16–20 hr. The saline-injected group produced no spawning. Our findings contribute to further understanding of exogenous hormones impact on golden rabbitfish reproductive endocrinology, refining breeding protocol and implications for fish propagation.

Effects of salinity, temperature and pH on the motility in Siganus guttatus spermatozoa

The effects of salinity, temperature and pH on the activity in the spermatozoa of Siganus guttatus were studied. Milt were collected from 8 wild mature males that came from a commercial hatchery. Sperm motility was measured with a VHS video-recorder and a video camera connected to a microscope. The results showed that most of the sperm were highly motile in 400-700 mM NaCl, the longest duration of sperm motility recorded in 600mM NaCl and the duration was 788.0±16.9 s. Sperm was not motile when suspended at pH 4, sperm motility was observed at pH 5, there was a relatively higher percentage of motile sperm in solutions at pH 5-8 (above 80%), the duration was the longest and achieved (769.0±19.8) s when pH was 8. The motility and duration increased within 10-25ºC and decreased at the range of 25-40ºC, the highest motility and the longest duration were all appeared at 25 ºC, they were (91.0±1.4) % and (725.0±21.2) severally. Optimum salinity, temperature and pH for S.guttatus reproduction was 600mM NaCl, 25 ºC and 8 respectively.

INFLUENCE OF SQUID LIVER MEAL IN MATURATION DIET ON GONADOSOMATIC INDEX AND GONADAL AMINO ACID CONTENT OF GOLDEN SPOTTED RABBITFISH, Siganus guttatus

A four months feeding trial was conducted to evaluate the effects of two maturation diets containing either fishmeal (FM) or squid liver meal (SLM) as the major protein source on growth, gonadosomatic index and gonadal bio-chemical profiles of golden spotted rabbitfish, Siganus guttatus. The two tested diets were formulated to be iso-nitrogenous (40%) and iso-lipidic (14%) and supplemented with several micronutrients specifically for gonadal development. The initial weight of golden spotted rabbitfish used were 352.6 ± 45.0 g and stocked into four of 2 m x 2 m x 2.5 m net cages with 25 fish per cage. The test diets were fed to the stocks twice a day. After four months feeding, the weight gains (WG) of broodstock fed the two diets were nearly similar in which FM had WG of 40.1 ± 2.2% and 42.8 ± 2.0% for SLM. The GSI of male fed SLM diet was similar to that of fed with FM. However, the GSI of female fed FM was 5.6 ± 0.1% significantly lower (P<0.05) than SLM which was 11.4 ± 0.5%. Furthermore, total amino acid (TAA) in spermatocyte was significantly (P<0.05) influenced by dietary SLM indicated by its higher TAA (62.4%) compared to TAA content of FM group (46.1%). Similarly, the TAA content in oocyte was significantly (P<0.05) improved when fed SLM. The dietary SLM did not affect the TAA content in the fillet of rabbitfish demonstrated by the similarity of the fillet TAA content in the two groups which was 55.6% for FM and 54.1% for SLM. Dietary SLM enhanced GSI of female broodstocks and profile of amino acid in the gonad of golden spotted rabbitfish, Siganus guttatus.

Seasonal changes in hepatosomatic index, gonadosomatic index and plasma estradiol‐17β level in captively reared female rabbit fish ( Siganus guttatus )

The seasonal changes in hepatosomatic index (HSI), gonadosomatic index (GSI) and plasma estradiol‐17β (E₂) level in female rabbit fish (Siganus guttatus) were investigated. The relationship between plasma E₂ levels with these indices and ovarian growth was also evaluated. Each month, at least 10 female broodfish were sacrificed to collect liver, ovary and blood for HSI, GSI and plasma E₂, respectively. GSI and HSI were calculated as percentage (%) of relative weight of gonad and liver to total body weight, respectively. Plasma E₂ level was measured using enzyme‐linked immunosorbent assay method (ELISA). Ovaries were cut and stained for histological observation. The results included seasonal changes in plasma E₂ levels, stages of ovarian development, GSI and HSI. The highest level of E₂ was observed in June (1,445.62 pg/ml) and during vitellogenesis (2,305 pg/ml). GSI and HSI values significant fluctuated monthly. The highest HSI and GSI were 1.72% in May and 3.58% in June, respectively. The pattern of plasma E₂ levels showed a relationship with GSI and different stages of ovarian development. HSI was associated with ovarian stages. During vitellogenesis, the highest value (1.9%) of HSI was observed. Histological sections showed that rabbit fish is a multiple spawner. These results contribute to further understanding of female rabbit fish reproductive biology in captivity. Important reproductive parameters such as HSI, GSI and E₂ can be used to indicate maturation status of this fish species.

Functional response of goldlined spinefoot rabbitfish Siganus guttatus (Siganidae, Perciformes) early juveniles to live zooplankton prey

Functional response of goldlined spinefoot rabbitfish Siganus guttatus (Siganidae, Perciformes) early juveniles to live zooplankton prey

Photoperiod manipulation in the induced breeding of the rabbit fish (<i>Siganus guttatus</i>)

In teleosts, reproductive development is a continuous process throughout ontogeny and is regulated by pituitary gonadotropins (GtHs). It has been established that fish has two distinct pituitary GtHs that parallel vertebrate follicle stimulating hormone (FSH) and luteinizing hormone (LH) with respective structural similarities. In the present study we investigated the spawning of the Golden rabbit fish Siganus guttatus after exposure to different photoperiod regimes. The role of photoperiod on spawning was studied by exposing female fish to three light regimes: 16h:8h light and dark; 16h:8h dark and light; and 24h continuous light. At every first quarter of the lunar cycle (new moon), the groups exposed to the photoperiod were induced to spawn by the injection of hCG at 2000 IU/kg fish. We observed that only 24 h exposure to continuous light induced successful spawning in female injected with hCG. Fish exposed to the other light: dark regimes could not be induced to spawn. Overall, these findings suggest that continuous light can be a triggering factor for the induction of maturation and spawning of this species under aquaculture conditions. 
 Keywords: Siganus guttatus, photoperiod, induced breeding, spawning.

Descriptions of two new acanthocephalans (Rhadinorhynchidae) from marine fish off the Pacific coast of Vietnam.

Two rhadinorhynchid acanthocephalans are described from marine fishes off the Pacific coast of Vietnam. Sclerocollum neorubrimaris n. sp. (Gorgorhynchinae Van Cleave & Lincicome, 1940) is described from the spine-foot rabbitfish Siganus guttatus (Bloch) (Siganidae) off Nha Trang. The new species is similar to the type-species, Sclerocollum rubrimaris Schmidt & Paperna, 1978 in most measurements and counts but has a posterior cephalic ganglion, a sub-ventral female gonopore, and one dorsal paravaginal filament bundle. In S. rubrimaris, the cephalic ganglion is near the middle of the receptacle, the female gonopore is terminal with two paravaginal filament bundles. The new species is distinguished from three other species of Sclerocollum Schmidt & Paperna, 1978 in proboscis hook formulas and the position of the female gonopore and cephalic ganglion. The issue of the importance of the position of the cephalic ganglion at the generic and sub-generic levels in the Acanthocephala is discussed. Females of Australorhynchus multispinosus n. sp. (Gorgorhynchinae) are described from the red cornetfish Fistularia petimba Lacépède off Nha Trang in the Pacific south. It is distinguished from the only other species of the genus, Australorhynchus tetramorphacanthus Lebedev, 1967, by having more trunk spines extending beyond the level of the proboscis receptacle and a smaller proboscis with considerably fewer hooks.

Kandungan Logam Berat Timbal (Pb) dan Kadmium (Cd) Pada Badan Air dan Ikan di Perairan Teluk Benoa, Bali

Heavy metals going into the aquatic environment will have an impact on the quality of the aquatic environment and affect the life of the biota in it. This study objectives is to determine the content of heavy metals Pb and Cd in water as well as in the Mullet Fish (Mugil cephalus) and Orange Spotted Rabbit Fish (Siganus guttatus) caught in Benoa Bay. The study was conducted from February to April 2018. The results showed that the content of heavy metals Pb and Cd in the water in Benoa Bay had exceeded the quality standards of metals dissolved in water for marine biota listed on Pergub Bali No. 16 of 2016. The value of Pb heavy metals in Mullet Fish and Orange Spotted Rabbit Fish in some samples have exceeded the maximum limit of heavy metal contamination SNI 7387: 2009. Cd heavy metal in Mullet Fish and Orange Spotted Rabbit Fish have exceeded the maximum limit of Cd metal contamination in fish and the processed product of 0.1 mg / Kg. Bioconcentration factor of metal Pb in Mullet Fish is included in the category of low accumulative properties of Pb heavy metals. BCF value of metal Cd in Mullet Fish shows that Mullet Fish has moderate accumulative properties against heavy metal Cd. Orange Spotted Rabbit Fish belongs to low category of accumulative properties against heavy metals Pb and Cd.

POLLUTION OF COASTAL AREAS OF JAKARTA BAY: WATER QUALITY AND BIOLOGICAL RESPONSES

Coastal development, growing urbanization and industrialization are the most important stressors of coral reefs worldwide. Jakarta is one of the largest megacities worldwide. The coral reefs of the Thousand Islands north of Jakarta have degraded dramatically over the last 30-40 years. While large-scale gradients (i.e., regional drivers) have been extensively studied and shown shifts and declines in coral cover and composition, local drivers and their impact on spatial community composition have been neglected. The aim of our study is to investigate the spatial impact of anthropogenic stressors on local and regional scales on coral reefs north of Jakarta. Our results demonstrate that reefs in the north of the Thousand Islands are separated from the reefs in Jakarta Bay (JB), where a direct impact of Jakarta can be seen. Local anthropogenic effects rather than regional gradients have shaped a spatial patchwork of differentially degraded reefs along the nearshore islands. The main anthropogenic stressor is pollution and sedimentation rate, NO2, PO4 and chlorophyll-a explain over 80% of the variation. Surfactants and diesel-borne compounds from sewage and bilge water discharges are common pollutants. Responses to combinations of selected pollutant with elevated temperature (+3°C) were determined in the metabolic performance of the coral reef fish Siganus guttatus. During combined exposure, metabolic depression was observed. Effects of pollutants were not amplified by elevated temperature. In a study about two dominant soft coral genera, Sarcophyton spp. and Nephthea spp., on dissolved inorganic nutrients (DIN), turbidity (NTU), and sedimentation combined with measurements of photosynthetic yield and respiratory electron system (ETS) activity water quality seems to control the relative abundance and physiology of dominant soft corals in JB. In order to reverse or prevent phase shifts from hard to soft corals, there is a need to manage the water quality better. It is concluded that the intense anthropogenic pressure from local as well as regional sources is responsible for the spatial structure and health of reefs. Therefore, improved spatial management with a focus on both local and regional stressors is needed for effective marine conservation.

Proximate composition and fatty acid profile in different tissues of juvenile Siganus guttatus fed with Enteromorpha prolifera

The proximate composition and fatty acid profile of five tissues (head, skin, bones, muscle and liver) of juvenile Siganus guttatus fed with Enteromorpha prolifera were investigated. The results indicated that: (1) The content of protein and fat among these five tissues showed a significant differences (P Lass Than 0.05). The muscle has the highest content of protein and the lowest content of fat. (2) The highest content of fatty acid in SFA is 16:0 in all five tissues, the highest content of fatty acid in MUFA is18:1n-9c (cis) in skin, bones, muscle and liver, while the highest content of PUFA is DHA in muscle. Muscle contained the highest value of DHA and EPA, the total content was more than 100 times in bones. Muscle tissue is rich in many important polyunsaturated fatty acids such as EPA, DPA, DHA, ARA and ALA, which has better nutritional quality and immune and health function.

Moonlight controls lunar-phase-dependency and regular oscillation of clock gene expressions in a lunar-synchronized spawner fish, Goldlined spinefoot

Goldlined spinefoot, Siganus guttatus, inhabits tropical and subtropical waters and synchronizes its spawning around the first quarter moon likely using an hourglass-like lunar timer. In previous studies, we have found that clock genes (Cryptochrome3 and Period1) could play the role of state variable in the diencephalon when determining the lunar phase for spawning. Here, we identified three Cry, two Per, two Clock, and two Bmal genes in S. guttatus and investigated their expression patterns in the diencephalon and pituitary gland. We further evaluated the effect on their expression patterns by daily interruptions of moonlight stimuli for 1 lunar cycle beginning at the new moon. It significantly modified the expression patterns in many of the examined clock(-related) genes including Cry3 in the diencephalon and/or pituitary gland. Acute interruptions of moonlight around the waxing gibbous moon upregulated nocturnal expressions of Cry1b and Cry2 in the diencephalon and pituitary gland, respectively, but did not affect expression levels of the other clock genes. These results highlighted the importance of repetitive moonlight illumination for stable or lunar-phase-specific daily expression of clock genes in the next lunar cycle that may be important for the lunar-phase-synchronized spawning on the next first quarter moon.

Bioaccumulation of Trace Metals in Golden Rabbit fish Siganus guttatus, Collected in Selected Seagrass Meadows of Northern Mindanao, Philippines

Bioaccumulation of Trace Metals in Golden Rabbit fish Siganus guttatus, Collected in Selected Seagrass Meadows of Northern Mindanao, Philippines The high-value Golden Rabbit fish (Siganus guttatus) was used to assess the current levels of trace metals zinc (Zn), copper (Cu), aluminium (Al) and cadmium (Cd) in 3 different seagrass meadows. The level of trace metals detected in the flesh of S. guttatus was at in the order of Al (18.360 mg/kg) >Zn (15.783 mg/kg) >Cu (1.0046 mg/kg) >Cd (0.100 mg/kg). Highest Al concentration was found in S. guttatus samples from Rizal, Zamboanga del Norte, as well as the toxic Cd. Human risk assessment based on the average Filipino consumption, showed that it is still safe to consume the fish S. guttatus on a daily basis. In general, Al was the most interactive element while Cd was the least. Regular monitoring of trace metals in these important seagrass meadows is recommended to avoid human health risk and ecological toxicity that may arise.

Toxicity of dispersed oil on Gold–saddle rabbitfish Siganus guttatus fry

The acute toxicity of dispersant Mardeus-455 added to water accommodated fractions (WAF) were evaluated in Gold-saddle rabbitfish Siganus guttatus fry after 72 h exposure under laboratory conditions. Mortalities of fry exposed to different concentrations of dispersed oil were recorded every hour for the first 6 h, every 3 h for the next 12 h, and every 6 h thereafter. Results showed that the higher the ratio of dispersant and WAF, the higher the mortality of the rabbitfish fry which may be due to the enhanced availability of polyaromatic hydrocarbons (PAH). The LC50 was computed at 3.692% of the oil volume. The application of dispersant in cleaning oil spills must be limited to reduce its harmful effect in the marine environment. Assessing toxicity of dispersed oil in fish fry may help understand the extent of environmental damage after cleaning oil spill using dispersant.

Pond Based Juvenile Production of Siganids: Growth Performance of 30-Day Post Hatch Siganus guttatus (Bloch, 1787) at Three Stocking Densities

Pond Based Juvenile Production of Siganids: Growth Performance of 30-Day Post Hatch Siganus guttatus (Bloch, 1787) at Three Stocking Densities

COMMUNITY STRUCTURE AND SPATIAL DISTRIBUTION OF FISH JUVENILE IN MANGROVE AND SEAGRASS HABITATS IN PRAMUKA ISLAND

This study was aimed to investigate the community structure of fish juvenile, spatial distribution and similarity from both adjacent habitats of mangrove and seagrass. This study was conducted in the eastern part of Pramuka island from April to June 2015. The samples were collected by using line transect method in three observation areas that were spatially connected i.e., mangrove, transition and seagrass zones. The result of the study from three observation zones revealed that there were found 24 species of fishes from 15 families i.e., Siganidae (4 species), Apogonidae (3 species), Ger-reidae (2 species), Terapontidae (2 species), Gobiidae (2 species), Labridae (2 species), Mugilidae, Nemipteridae, Hemiramphidae, Sphyraenidae, Monacanthidae, Atherinidae, Pomacentridae, Lut-janidae, and Lethrinidae (each of them 1 species). According to community structure, the adjacent ob-servation zones did not show a significant difference in the number of species, abundance, and bio-mass. According to fish distribution, fish species in transition zone and seagrass zone were relatively similar and dominated by Gerres oblongus, Fibramia lateralis, and Siganus canaliculatus. Mean-while, in mangrove zone revealed a significant different of fish species than in transition and seagrass zones. In mangrove zone, fish species was dominated by Gerres oblongus and Siganus guttatus. Keywords: spatial distribution, juvenile, mangrove, seagrass, pramuka Island, Siganidae

Effects of Thyroxin and Domperidone on Oocyte Maturation and Spawning Performances in the Rabbit Fish, Siganus guttatus

AbstractThyroxin (T4) is proven to have various functions in fish reproduction. In this study, we investigated oocyte maturation and spawning performance in the rabbit fish, Siganus guttatus, orally exposed to different doses of T4 (0.05, 0.25, and 0.5 mg/kg fish) during vitellogenesis. No statistically significant differences of reproductive characteristics were observed among the treatments. However, the group that was exposed to the dose of 0.5 mg/kg spawned after receiving a hormone injection. The findings suggest that feeding T4 during vitellogenesis did not advance oocyte maturation, but probably could induce spawning in rabbit fish. In a separate experiment, we investigated the effects of orally administered domperidone (DOM) on reproductive performances of the female rabbit fish. The study showed that oral administration of DOM during the early stages of the reproductive cycle had no significant effects on oocyte maturation and spawning performance. Overall, these findings suggest that DOM may not be needed for the induction of maturation and spawning of this species under aquaculture conditions. These practical investigations were conducted with a view to attempt reducing drug use, production costs, and support sustainable aquaculture.

Metabolic performance of the coral reef fish Siganus guttatus exposed to combinations of water borne diesel, an anionic surfactant and elevated temperature in Indonesia

Jakarta Bay in Indonesia and its offshore island chain, the Thousand Islands, are facing extreme pollution. Surfactants and diesel-borne compounds from sewage and bilge water discharges are common pollutants. However, knowledge of their effects on reef fish physiology is scarce. This study investigated combined and single effects of a) the water accommodated fraction of diesel (WAF-D, determined by ƩEPA polycyclic aromatic hydrocarbons (PAHs)) and b) the surfactant linear alkylbenzene sulfonate (LAS) on metabolic performance of the coral reef fish Siganus guttatus. Responses to combinations of each pollutant with elevated temperature (+3°C) were determined. Short-term exposure to WAF-D led to a significant decrease in standard metabolic rates, while LAS led to an increase. During combined exposure, metabolic depression was observed. Effects of pollutants were not amplified by elevated temperature. This study highlights the need to reduce import of these pollutants and to avoid negative long-term effects on fish health.