Siganus Guttatus Research Articles

Exploring Sound Frequency Detection in the Golden Rabbitfish, Siganus guttatus: A Behavioral Study.

This study investigates the auditory capabilities of Golden Rabbitfish (Siganus guttatus) and the potential efficacy of sound-based deterrent methods for behavior control. Behavioral experiments were conducted on Golden Rabbitfish to assess their responses to sound stimuli. Sinusoidal pulses in the range of 100~800 Hz, based on previous research on auditory evoked potentials (AEPs), were utilized. An analysis of behavioral trajectories, swimming speed, and acceleration changes revealed the fish's reactions to varying frequency sound stimuli. The results indicate that Golden Rabbitfish exhibited increased swimming activity and speed when stimulated by sound and notably moved away from the source under prolonged exposure to low-frequency acoustic signals. Specifically, the fish displayed the most significant response to 200 Hz sinusoidal pulses with a response threshold of 113~126 dB. These findings suggest that Golden Rabbitfish are particularly sensitive to low-frequency noise, aligning with AEP study outcomes. This study concludes that employing sound stimuli to deter Golden Rabbitfish in practical settings holds promise for mitigating economic losses in seaweed farming due to Golden Rabbitfish grazing.

INFLUENCE OF TAURINE ON LARVAL EYE DEVELOPMENT AND GROWTH PERFORMANCE OF GOLDEN RABBITFISH (Siganus guttatus)

ARTICLE HIGLIGHTS- Taurine improves eye development in golden rabbitfish larvae- Enhanced growth performance with taurine-enriched rotifers- Taurine positively impacts fish eye and body growthABSTRACTGolden rabbitfish (Siganus guttatus) is an emerging species for aquaculture industry, despite constrains faced on commercial scale of seed production due to the high mortality during the first-feeding stage. An experiment was conducted to determine the effect of taurine through enrichment of rotifers as live-feed on eye development and growth performance of larval golden rabbitfish. Observation of eye development was carried out by measuring eye diameter of the larva and development of the retina based on histology assessment. Growth performance was measured for absolute growth and fin development of the larvae and survival rate. The results showed that taurine-enriched rotifer generally provided better performances for eye development and growth of larval golden rabbitfish compared with control (without taurine). Increase of taurine dose up to 0.050 g/L resulted in an increase of eye diameter, absolute growth, fin development and survival rate. Further increased increment of the taurine tended to decrease the values of the measured parameters. The eye diameter of larval golden rabbitfish fed with 0.050 g/L taurine-enriched rotifer was significantly wider (106.1±9.8 µm) (P < 0.05) compared with control (58.2±14.3 µm), but did not significantly differ from other doses of taurine (P > 0.05). Body width of larvae fed with 0.050 g/L taurine-enriched rotifer was significantly higher (127.3±14.6 µm) (P < 0.05) compared with control (98.8±18.3 µm). In regard to eye development, growth performances (total length, fin development and survival rate), dose of taurine for rotifer enrichment fed to larval golden rabbitfish Siganus guttatus was 0.050 g/L.

Accumulation of mercury in muscle of orange-spotted spinefoot(Siganus guttatus Bloch, 1787) by age and season in the coastal Quang Binh

Orange-spotted spinefoot (Siganus guttatus) is not only a fish with high economic value, rich in nutrients, but also popular with people for consumption. This research was carried out from November 2021 to May 2022, in the coastal and estuaries of Quang Binh province. A total of 60 samples of orange-spotted spinefoot were collected by age group, wet season, and dry season to analyse the accumulation of mercury (Hg) in their muscles. The Hg concentration was analysed by cold vapour atomic absorption spectroscopy. Research results showed a strong correlation between the length and weight of fish both in the wet and dry seasons. The age group has a strong influence on the accumulation of Hg in their muscles, the older fish group has a higher aggregation of Hg than the younger fish group. Although the average value of Hg concentration in the muscle of orange-spotted spinefoot in the dry season is higher than in the wet season, analysis results of “Tukey’s HSD test” showed that there was no significant difference.

Cloning, tissue specificity and regulation of expression of genes of four key enzymes related to long-chain polyunsaturated fatty acids (LC-PUFA) biosynthesis by ambient salinity during embryogenesis in the marine teleost Siganus guttatus.

The rabbitfish Siganus canaliculatus was the first marine teleost reported to possess long-chain polyunsaturated fatty acid (LC-PUFA) biosynthetic ability, and the related molecular mechanisms have been well clarified. Here, we investigated the LC-PUFA biosynthesis capability of the congeneric rabbitfish S. guttatus. First, cDNAs of genes for four key enzymes related to LC-PUFA biosynthesis, namely Δ6Δ5 fatty acyl desaturase (fads2) (1335 bp; 445 aa), Δ4 fads2 (1335 bp; 445 aa), and elongation of very long chain fatty acid proteins (elovl5) (873 bp; 291 aa) and elovl4 (906 bp; 302 aa) were cloned from the liver of S. guttatus. The Δ6Δ5 fads2, Δ4 fads2 and elovl5 genes showed high expression in brain, liver, spleen, gallbladder, and intestine but relatively low expression in eye, whereas the elovl4 gene showed specific and high expression in eye. During embryogenesis, mRNA expression of Δ4 fads2 and elovl4 was detected from 8 h post-fertilization (hpf) and then maintained a high level to 24 hpf, while mRNA expression of Δ6Δ5 fads2 and elovl5 reached a peak at 14 hpf but then declined. In addition, ambient salinity (32 ppt and 20 ppt) exerted some regulatory influence on the expression of the four genes during embryogenesis. The levels of C18 PUFA precursors and, especially, PUFA and DHA of the embryos, decreased from 17 hpf to 24 hpf. These results suggested that S. guttatus, similar to the congeneric S. canaliculatus, would have capability for LC-PUFA biosynthesis, which is still not activated at the fertilized egg stage.

Effects of Iodine Treatment on the Development of Eggs and Larvae of Rabbitfish (Siganus guttatus Bloch, 1787)

Abstract Iodine is proven to be an effective disinfectant for fish eggs and is commonly used in a hatchery to improve hatching and survival rates. However, tolerance to iodine can vary in different fish species, and it is essential to determine the optimal concentration to ensure successful hatchery production. This study investigated the optimum concentration and exposure time to iodine during incubation to improve rabbitfish larvae’s hatching and fertilization rate from 4/2022 – 8/2022 in Thua Thien Hue, Vietnam. The study consisted of two experiments: Experiment 1 focused on different iodine concentrations: 0 ppm (C1), 50 ppm (C2), 100 ppm (C3), and 150 ppm (C4). Experiment 2 explored three exposure times: 10 minutes (T1), 20 minutes (T2), and 30 minutes (T3) to increase the fertilization, hatching, and survival rates at five days post-hatching. Data were compiled, analyzed, and compared by ANOVA using SPSS ver. 22.0. The results showed that 100 ppm iodine concentration at 20 minutes of exposure resulted in the optimum hatching, fertilization, and survival rates of S. guttatus during artificial reproduction. In the future, integrated solutions in the use of iodine solution for egg treatment and natural food supplementation at the larval stage should be recommended to improve the efficiency in artificial hatchery production of Rabbitfish. Highlight Research The concentration and incubation time of rabbitfish (Siganus guttatus) eggs affect the production efficiency of fingerling fish. Iodine concentration of 100ppm for 20 minutes is the best to treat fish eggs before incubation. The fertilization rate of eggs, hatching rate, and survival rate of larva after 5 days of hatching when washing by iodine concentration of 100 ppm was 86.44 ±84%, 96.14 ± 1.05%, 58.65 ± 7.60% respectively.

Characterization of Bacillus subtilis (BR 610) isolated from the intestines of Rabbitfish, Siganus guttatus, maintained in Floating Net at Awerange Bay, Barru

The use of some species of Bacillus as a probiotic has been widely reported. In general, using probiotics in the exact isolation location will improve the performance of these probiotics. This study aims to characterize the Bacillus subtilis (BR610) isolate, successfully isolated from the intestines of Rabbitfish previously cultivated in the floating net of Awerange bay, Barru, South Sulawesi. The research includes morphological characterization of BR610 isolates, activity tests of amylase, cellulose, and proteinase enzyme. BR610 isolate inhibition test against several types of pathogenic bacterial isolates (Vibrio harveyi, V. parahaemolyticus, V. alginolitycus, and Streptococcus) as well as BR610 isolate resistance test against various kinds of antibiotics. The results showed that the Bacillus subtilis (BR610) has a spherical morphology, wavy edges, flat elevation, and is cream-white in color. BR610 can produce the enzyme amylase 20.36±17.8mm, proteinase 14.2±6.7mm, and Cellulose 20.9±2.7mm. These isolates can also inhibit the growth of V. harveyi (13.0±0.3mm), V. alginolyticus (15.1±2.8mm), V. parahaemolyticus (14.7±2.7mm), and Streptococcus (17.6±1.6mm). Bacillus subtilis BR610 is still worthy of being used as an environmentally friendly probiotic because it is still sensitive to several types of antibiotics tested.

The Right Time to Add A Commercial Feed for Rabbitfish (Siganus Guttatus) from 10 to 25 Days of Age

A study on the timing of the start of supplied commercial feed for rabbitfish fry (Siganus guttatus) to determine the optimal survival rate and growth in terms of length and weight at 30 days. Four trials, 3 replicates each, and 4 batches in 2020 – 2022 differed when supplied commercial feed to fish fry at 10, 15, 20, and 25 days old before provided commercial feed, all larvae fed by zooplankton and phytoplankton. The results showed that the rabbitfish fry supplemented with commercial feed at 20 days old (NT3 (20)) showed the fastest growth in length, an average of 18.53 mm at 30 days old, average daily increase of the size of 0.65 mm/day and growth rate of size of 5.95% and 36.98 to 38.01g/head of trial 3 (TN3) (20) in 4 feeding batches, and the highest survival rate of 71.85% and weight at the final feeding stage at 30 days of age. There were significant differences in weight growth for the fish fry from at last feeding, and during the fry stages, fish tends to grow in length continuously, then increase in weight later. There was a significant impact by stomach volume at 30 days of the age of NT3 was much higher than in other trials. The other three timing trails of commercial feeding did not have any differences and showed less effectiveness than the treatment of fish at 10, 20, and 30 days old in terms of growth in length, weight, and survival rate. The stomach volume of Fries was stimulated by feedstuffs and early supplied feed to fries when they could eat; trial 3 (NT20) was the biggest stomach size, with a circumference of 11,76 mm2.

Determining the Effect of Different Ecological Conditions on the Maturation of Rabbitfish (Siganus guttatus)

A study aimed at the rabbitfish Siganus guttatus (Bloch, 1787), the reproductive ability of one economically important marine and brackish fish in Giang lagoon systems and marine Asia. The future expectations of mariculture development were decided in Vietnam. The region had enough fingerlings for intensive culture and polyculture to contribute to environmental conservation and sustainability. There were 3 experiments in 3 different ecosystems for fish culture and maturity by feeding a commercial feed and finding suitable areas for the maturing period. The results showed that the growing fish kept in cages on the lagoon had the best growth and rate maturity, much higher than fish in cages of shrimp ponds and plastic bottom ponds, as showed a much bigger size of body, 610 g/head for females and 542 g/head for males, while other culture more 500/head, especially after 3 months of feeding, more than 20% matured for females, they reached more 50% at 6 months feeding. The length at first sexual maturity was 28.87 to 31.20 cm and 27.47 to 29.20 cm for females and males, respectively. The potential ova diameter is from 405 to 483 µm, P < 0.05; the benefit for spawning, gonads maturity stages, with GSI (gonadal-somatic index), 3.03 to 4.53 were opportunities for the spawning season, ova diameter and fecundity and the gonadal-somatic index were differed significantly (P < 0.05) males and females. This result showed the maximum (peak), and all fish can mature and get to spawning. In conclusion, different ecosystems impacted maturity and spawning during the moon season.

Morphological variation in the first vertebra among acanthomorph fishes – a guide for identifying fossil centra from microvertebrate sites

Innumerable fossil fish specimens have been recovered from fossil microvertebrate sites – areas in which small, isolated elements of the skeleton from multiple individuals have been amassed. The accumulated skeletal remains, often the result of transportation by moving waters, provide an important window on the fauna that was present in a wider area during a broader period of time than that represented by individual articulated specimens. Although microvertebrate localities provide important records of taxa, the disarticulated condition of the fossil elements can cause difficulties for taxonomic identification. This is particularly true for fish, which are most commonly represented in microfossil sites by vertebral centra; however, fish centra are notoriously difficult to identify at lower taxonomic levels, partly because of the vast numbers of living fish and lack of comparative collections. Arguably, the most distinctive vertebral centrum among all fish is the first abdominal centrum of Acanthomorpha. In acanthomorphs, in contrast to all other fishes, the first centrum bears two distinct (separate left and right) facets for articulation with the exoccipitals, which are normally positioned more or less dorsolateral to the articular facet for the basioccipital, forming a unique tri-partite morphology. We here document the first centrum of numerous acanthomorph fishes, and assess the morphologies for taxonomic or phylogenetic consistencies that would allow us to identify isolated centra to a particular acanthomorph group. Features we document include: whether the neural arch is fused to the centrum (as in the paracanthopterygians Lota lota and Percopsis omiscomaycus) or autogenous (most acanthopterygians); whether the left and right facets for the exoccipitals meet in the midline (e.g., Boops boops) or are widely separated (e.g., percids and scorpaenids); and the bone texture on the centrum which may be an anastomosed network forming many small spaces (e.g., Scomber spp.) or a more solid network with no spaces (e.g., Channidae), among others. From our examination of specimens, we note several unique features among the taxa examined: the first centrum of Monopterus alba is opisthocoelus and the first neural arch has processes extending posteriorly; the first centrum of Leiognathus equula has ventral process extending from the facets for articulation with the exoccipitals; there are anterior accessory processes on the neural arch of Parachanna obscura; the transverse processes of Chlorurus sp. and Scarus vetula extend from the ventral area of the centrum and form long triangular processes; and the neural arch of Siganus guttatus has ventrolateral processes that extend to the level of the ventral surface of the centrum. We also find that the overall morphology of the first centrum is conservative within a family, indicating that in many cases fossil material may be identified at least to the family level.

Microplastic Abundance and Characteristics in Rabbitfish Siganus guttatus and Parrotfish Scarus ghobban from the Local Market of Zamboanga City, Philippines

Microplastic pollution is a global problem. In a particular area of concern, Rabbitfish and Parrotfish are good bioindicators of microplastic pollution because they have high site fidelity. This study aimed to investigate the MPs contamination in Rabbitfish Siganus guttatus and Parrotfish Scarus ghobban sold in the local public market of Zamboanga City, Philippines. Thirty-five (35) samples of each fish bought from the local Magay public market, Zamboanga City, were subjected to MP’s laboratory analysis. The study revealed that all fish samples had MPs in their guts. Rabbitfish have greater MPs at 51.97 per sample than Parrotfish at 19.29 per sample. Regression analysis showed a significant negative relationship between the weight and length of Rabbitfish and the MPs abundance but no significant difference in Parrotfish; most of the MPs ingested by both species can be attributed to the area where they are caught. Blue filaments are the most present in Rabbitfish, while red filaments are most present in Parrotfish. These filaments are from terrestrial sources, mainly from textiles washed into the oceans via rivers and sewers from households.

Nitrogen and phosphorus budgets of a polyculture system containing Penaeus vannamei, Siganus guttatus, and Selenotoca multifasciata

AbstractThe study was designed and conducted to optimize the structure of polyculture for Penaeus vannamei, Siganus guttatus (omnivorous fish), and Selenotoca multifasciata (carnivorous fish), and to compare the changes in yield, survival, and utilization rates of nitrogen (N) and phosphorus (P). Five treatments were performed as follows: Control (C) (0.0719 kg/m3, 0, 0), PSS1(0.0719 kg/m3, 0.0018 kg/m3, 0.0008 kg/m3), PSS2 (0.0719 kg/m3, 0.0033 kg/m3, 0.0016 kg/m3), PSS3 (0.0719 kg/m3, 0.0047 kg/m3, 0.0023 kg/m3), and PSS4 (0.0719 kg/m3, 0.0064 kg/m3, 0.0031 kg/m3) (with P:Penaeus vannamei, S:Siganus guttatus, and S: Selenotoca multifasciata). The yield and survival of P. vannamei in different treatments were significantly different (P<0.05), with the highest yields being P. vannamei (718.75 kg/hm3), S. guttatus (32.97 kg/hm3), and S. multifasciata (15.63 kg/hm3) for treatment PSS2. The highest survival of P. vannamei was 89.4 ± 1.6% for treatment PSS2, while the highest N and P utilization rates were 27.7% and 37.5% for treatment PSS3. The polyculture mode when using a suitable density can improve production and survival of P. vannamei, as well as the utilization rates of N and P.

Juvenile yield and adult abundance, genetic diversity and structure, and linkages among marine habitats for goldlined spinefoot (Siganus guttatus) in the coastal waters of Vietnam

Juvenile yield and adult abundance, genetic diversity and structure, and linkages among marine habitats for goldlined spinefoot (Siganus guttatus) in the coastal waters of Vietnam

UKURAN KEPADATAN DAN POTENSI IKAN BARONANG TOMPEL (Siganus guttatus Bloch 1787) DI TELUK KOTANIA SERAM BAGIAN BARAT

Spotted rabbitfish (Siganus guttatus Bloch 1787) are valuable commercial fish species. Research on the fish species has been carried out in the waters of Kotania Bay, aiming to obtain information about size, density and potential of the fish species. Data are collected about total length (TL), weight and number of individual fish at four observation stations using 120m length of bottom gillnet with mesh size of 2.0, 2.5, 3.0 dan 3.5 inches. The bottom gillnet is operated in a circle that starting two hours before the low tide then the spotted rabbitfish caught are collected at the low tide. The results showed that the total length of the spotted rabbitfish is in the range of 11,3 – 33,9 cm which has dominated by fish with sizes of 18, 24 and 26 cm. Mean density of the fish is 209 individual/ha, so the abundance the fish in the area of seagrass beds 823.62 ha was estimated as 172.486 of fish individual, it’s 72,51% or 125.070 individuals are those fishes that has spawned for the first time. The mean weight of the spotted rabbitfish at this size is 533,51 grams, so calculated biomass is 66,73 tons and MSY value is 33,365 tons in wet season.

Sea lettuce (Ulva lactuca) meal combined with soybean meal in a low fishmeal diet enhanced the growth and feed intake of cultured golden rabbitfish (Siganus guttatus) during the nursery stage

A preliminary feeding trial was conducted to evaluate the effect of utilizing a high level of sea lettuce (SL), Ulva lactuca meal, as a dietary ingredient on the growth and biochemical composition of the golden rabbitfish, Siganus guttatus. Two treatments included one diet containing high SL meal combined with soybean (PP) and another diet that used fish meal as the primary protein source (FM). Golden rabbitfish were stocked into 8 of 120 L fiberglass tanks with a density of 20 fish/tank and fed for 15 weeks. The weight gain of the fish-fed PP diet was 453% higher than those provided with FM (343%). Similarly, the SGR of fish fed the PP diet was higher (1.40 %/d) compared to the PF diet (1.22 %/d). The FCR of the FM diet was lower (1.3) compared to the PP diet (1.6). Fish fed the FM diet contained a higher ash content than those fed the PP diet (14.9 vs 10.1%). Crude protein content in body fish was relatively similar for both diets. Including sea lettuce meal at 30% combined with a high level of soybean meal in a low fishmeal diet, they produced better growth performances of rabbitfish during the nursery stage.

Growth performances and gonadal development of golden rabbitfish, Siganus guttatus fed with two types of floating diets in sea cages

A feeding trial was designed to evaluate the effects of utilizing floating pellets on the growth performances, feed utilization and gonadal maturation of the golden rabbitfish, Siganus guttatus. The treatments were two kinds of commercial floating pellet containing different crude protein (CP) levels which were 26% (FD1) and 33% (FD2). The tested diets were fed to golden rabbitfish. Golden rabbitfish with initial body weight of 239.7±4.8 g were stocked into six sea cages with size of 2x2x2 m3 with density of 50 fishes/cage. The feeding trial lasted for 120 days with results showed that the growth performances of weight gain and specific growth rate were significantly higher (P<0.05) in fish fed FD2 diet (55.0±3.7% and 0.37±0.02 %/d) compared to those fed with FD1 diet (41.7±1.6 and 0.29±0.01%/d), respectively. Both female and male fishes had developed gonad at the end of feeding trial. The gonadosomatic index (GSI) for spermatid significantly higher (<0.05) in fish fed FD2 (4.8±0.6%) than FD1 group (3.4±0.3%). Similarly, the GSI for oocyte of fish fed FD2 diet (8.9±1.0%) was significantly higher than the group fed FD1 diet (4.2±0.5%). The FD2 diet produced higher protein content in the whole body and fillet. In contrast, lipid content of whole body and fillet of fish fed FD1 diet was higher than FD2 diet. As conclusion, better growth performances and gonadal development was found in fish fed FD2 diet, a floating diet containing approximately 33% CP.

Effect of feeding rate on growth and feed conversion ratio in the cultivation recirculation systems of multi tropic model

The effects of feeding rate (0.5%, 7.5%, and 10% body weight [BW] per day [BW day−1]) on the growth, survival rate, and feed conversion ratio of rabbit fish, Siganus guttatus, (initial BW of 2.0 ± 0.5 g, density of 16 individuals 80 L−1) were investigated in a water recirculating aquaculture system of Integrated Multi Trophic Aquaculture (IMTA model involving mussel Perna viridis, sea urchin Diadema sitosum, and seaweed Kappaphycus alvarezii. Triplicate groups of fish were fed an comercial diet (55.4% protein, 14.1% lipid) four meals a day (8 a.m, 12 a.m, 4 p.m, dan 8 p.m) for 12 weeks. Survival rate (SR), body weight gain (BWG, specific growth rate (SGR), and feed conversion ratio (FCR) significantly affected (p<0.05) by feeding rate. Experimental application of the IMTA model shows that although the amount of feed given is higher, it can produce better growth performance.

Evaluation of seaweed, Ulva lactuca as a fresh diet for nursery stage of golden rabbitfish, Siganus guttatus

Ulva lactuca is a green seaweed with a high potency to be used as fish diet. The feeding trial aimed to evaluate the use of U.lactuca as fresh diet for the nursery of golden rabbitfish Siganus guttatus. Five treatments were evaluated, namely 100% fresh Ulva (FU), the combination of fresh Ulva and dry pellet with the ratio of 75:25% (UP1), 50:50% (UP2), 25:75% (UP3), and 100% dry pellet (DP) with three replicates. Golden rabbitfish with a mean initial weight of 6.2 g were stocked into fifteen rearing tanks at a density of 20 fish tank−1. After 90 days, growth responses differed significantly amongst dietary groups. Fish fed DP had similar weight gain (219.86%) to UP3 (232.21%), and its specific growth rate (1.29%/day) was similar to UP2 (1.11%/day) and UP3 (1.33%/day), but significantly different (p<0.05) from FU (SGR -0.25%/day; WG -19.97%). The survival rate of fish fed UP2 (98.33%) was significantly different (p<0.05) from FU (80.00%). The fish body color fed FU had bright yellowish color and high carotenoids (14.69 µg g−1) compared to DP. The combination of fresh Ulva with pellet at the same ratio of 50% and 25:75% similar to the 100% pellet diet can support the fish growth.

Selection of prospective probiotic bacteria from the intestines of Rabbitfish, Siganus guttatus as a fermenter for fish feed raw materials

Rabbitfish is classified as herbivorous fish by utilizing plants as a staple food, so it has the potential to contain microflora in the digestive tract. The study aimed to select bacteria from the intestines of Rabbitfish as probiotic candidates for degradation of feed ingredients. At the beginning of the study, microbial dissolution of the intestines of 10 Rabbitfish measured weight and body length 127 ±20.1 g and 191.4±1.17 cm, healthy and not deformed, obtained from the waters around the island of Salemo, Regency. Pangkep. At this stage, they have successfully isolated 72 isolates. Then make a selection of bacteria based on the activity of extracellular enzymes by testing the hydrolysis ability of starch using Zobel media adding 1% soluble starch, protein hydrolysis using Zobel media adding 1% skim milk, cellulose hydrolysis using Zobel media adding 1% CMC. The ability of the insulator to hydrolyze starch ranges from 0.4 cm; to protein to 2.4 cm; cellulose to 1.5 cm. Based on these results, 10 isolates were selected as probiotic candidates, namely 411; 413; 422; 427; 430; 434; 437; 452 and 455. The next stage of the pathogenicity test of 10 selected isolates. Each isolate with a density of 106 CFU/mL was injected into 5 juveniles of healthy Rabbitfish intramuscularly as much as 0.1 mL. Monitoring is carried out daily for 10 days after infection to evaluate clinical signs of the disease in test fish. The results obtained showed that no symptoms of pain, injury, or death were found, so it was concluded that the bacterial isolate was not pathogenic.

Effects of protein levels of commercial diets on the growth performance and survival rate of rabbitfish (Siganus guttatus) at the nursing stage

This study aimed to determine the effect of a commercial diet's protein level on the fry-to-fingerling stage. Thirty days-old fries having the initial length and weight of 18.25 ± 0.15 mm fish-1 and 0.036 ± 0.50 g fish-1 respectively have been used in this study. Diet having three protein levels i.e. 30% (trial 1 as control), 35% (trial 2), 40% (trial 3), and 45% (trial 4), respectively, have been used to evaluate the effect of protein, and each trial has been repeated three times. During the study, stocking density was allocated to 1000 fish per composite tank with a volume of 1 m3. After 30 days of rearing, the weight of fingerlings in trial 1 reached up to 1.50 ± 0.02 g fish-1 and it was recorded as 1.52 ± 0.01g for trial 2, these two were lower than that of trials 3 and 4, where fingerling weight was reported 1.69 ± 0.01 and 1.58g fish-1 respectively and obtained the best weight compared to others. The length of fingerlings at the end of the experimental period was also changed in different trials and it was recorded 47.12; 46.92; 50.97; and 48.89 mm fish-1 for trail 1, 2, 3, and 4 respectively, among the tested combinations lower fingerlings length was recorded for trial 2 (35% CP), but it is not significantly different for trial 1 and 2 and a significant difference (P &lt; 0.05) was reported for trail 2, 3, and 4. The survival rate of fingerlings ranged from 67.27 to 72.33%. Meanwhile, the herd distribution coefficient variation (CVW) in the treatment using 40% protein (trial 3) was the highest at 72.33% (p &lt; 0.05). The results of the study can be concluded that the level of protein has a significant effect on the various growth parameters of fingerlings.

Some indicators for assessing stock of golden rabbitfish (Siganus guttatus, Bloch 1787) in Wakatobi Waters, Southeast Sulawesi, Indonesia

Golden rabbitfish (Siganus guttatus) is an important species to people in Wakatobi islands that are surrounded by the Banda Sea and the Flores Sea. They catch the fish for local consumptions and trade processed fish to other areas. This study aims to determine estimates of the fish's growth, mortality, and exploitation rates. The study was conducted from January to November 2016 in Wakatobi. Analysis was carried out the FISAT II package. The fish length ranged from 8.0 to 49.0 cm with an average of 26.19 cm. The growth pattern of male fish was positive allometric while for female fish was allometric negative. The sex ratio was inbalanced. The estimate of length at first capture (Lc) was 27.65 cm (FL) while the estimate of length at first maturity (Lm) was 30.49 cm (FL). The natural mortality (M) was 1.51/year while the fishing mortality was 1.28/year and the exploitation rate was 0.46/year. The SPR was 0.49, indicating the exploitation rate of Siganus guttatus in the studied areas is still at the optimum condition.