Journal of Fisheries and Environment

Effects of Stocking Density and Water Management on Stress Responses and Reproductive Performance of Bighead Catfish (Clarias macrocephalus) Female Broodstock after Hormone Injection

Thu, 01 Aug 2024 00:00:00 +0700

Stress responses and reproductive performance of female bighead catfish (Clarias macrocephalus Günther, 1864) broodfish in response to different stocking densities and water systems after hormone injection were investigated. The experiment followed a 4×2 factorial in a completely randomized design, wherein the female broodfish were injected with 30 mg LHRHa and 5 mg domperidone per kg of fish. They were then stocked at four different densities: 5 fish·m^-2, 10 fish·m^-2, 15 fish·m^-2, or 20 fish·m^-2. They were provided with either a water flow-through or stagnant water (without water exchange). The results revealed that neither the densities nor the water systems affected the stress response, as measured by blood plasma cortisol. Regarding reproduction-related traits, blood 17b estradiol concentration and the percentage of females spawned were not significantly influenced by these two factors (p>0.05). Interestingly, the water flow-through system tended to induce faster ovulation and spawning compared to the no water exchange system. Additionally, the water flow-through system also significantly (p<0.05) contributed to better reproductive outcomes, namely higher egg hatching rates and larval survival, compared to the no water exchange system. The loss of spawned female within 72 h after spawning was not affected by density or water system. In conclusion, this study suggests that female broodfish should be kept at a stocking density of 20 fish·m^-2 in the water flow-through system following hormone injection for optimal reproductive performance.

Fish Assemblage Structures in Intertidal and Subtidal Seagrass Habitats in Trang Province, Southern Thailand

Thu, 01 Aug 2024 00:00:00 +0700

As a first step to clarify the functions of intertidal seagrass habitats in a coastal ecosystem, for which information is still scarce to date, we investigated fish assemblage structures in these habitats during the daytime at Trang, Thailand, in March, June, September 2017 and December 2018, and compared them with those in nearby subtidal seagrass habitats as well as adjacent sand/mud flats. Both intertidal and subtidal seagrass habitats as well as intertidal sand/mud flats, supported fish assemblages with high species diversity, with total species numbers ranging from 36 to 41 in the former, and from 35 to 55 in the the latter. On the other hand, species diversity in subtidal open sand/mud flats was relatively lower, with a total species numbers of 21. Total fish abundances showed similar patterns in both intertidal and subtidal seagrass habitats. Dominant species such as Siganus canaliculatus, Petroscirtes variabilis and Monacanthus chinensis were common in these habitats. In sand/mud flats, Acanthosphex leurynnis, Siganus canaliculatus and Sillago sihama were dominant species. The similarity in fish assemblages between subtidal and intertidal seagrass habitats may be due to prey abundance patterns, while other factors could also influence fish assemblage structures in sand/mud flats. These findings suggest that both intertidal seagrass and open sand/mud flats are habitats with high fish diversity and abundances and should be considered in the establishment of management programs for coastal ecosystems.

Effect of Dietary Carotenoids on Survival, Growth, and Carotenoid Accumulation in Mandarinfish, Synchiropus splendidus (Herre, 1927)

Amonrat Kanokrung, Khakhanang Ratananikom, Rawiwan Watanadilok — Thu, 01 Aug 2024 00:00:00 +0700

The color of ornamental fish is crucial in determining their value, and it is always compromised when reared in captivity. This study aimed to examine the effects of dietary carotenoids from Artemia enriched with four microalgae on growth, survival, and carotenoid accumulation in mandarinfish, Synchiropus splendidus. Artemia nauplii were enriched with one of the following microalgae: Tetraselmis gracilis, Isochrysis galbana, Nannochloropsis oculata and Dunaliella salina. Subsequently, the enriched Artemia nauplii were fed to 60 days old mandarinfish for a period of 60 days. At the end of the feeding period, survival was 100% for all dietary treatments. The growth performance varied significantly (p<0.05) for the various diets. The highest weight gain, length gain and specific growth rate (SGR) were found in the mandarinfish fed with the diet enriched with T. gracilis (weight gain = 0.80±0.58 g; length gain = 0.27±0.02 cm; SGR = 2.98±0.03% day^-1). The highest total carotenoid content of the mandarinfish was observed in the fish fed with Artemia enriched with T. gracilis and I. galbana at 1.79±0.32 mg·g^-1. The results showed that mandarinfish accumulated the highest amount of beta-carotene when fed with Artemia enriched with T. gracilis (0.39 μg×g^-1of wet weight). In addition, all of the treatment groups accumulated the carotenoid pigments, beta-carotene, echinenone, canthaxanthin, and zeaxanthin but in different amounts.

Comparing Epoxy and Para Rubber Glue for Attaching Satellite Tags to Juvenile Green Sea Turtles: Implications for Behavior and Growth

Suwat Jutapruet, Nattarinee Kongnoon, Supparoek Sasi, Hirun Kunghae — Thu, 01 Aug 2024 00:00:00 +0700

This study aimed to investigate the efficiency of epoxy and para rubber glue for attaching artificial satellite tags to juvenile green sea turtles (Chelonia mydas). Two groups of 10 juvenile C. mydas each were monitored for two months before and after tag attachment. Measurements and analyses of straight carapace length (SCL), straight carapace width (SCW), weight, and behaviors were conducted. The results showed that there were no significant differences in the final SCL, SCW, and weight of the turtles between the two adhesive treatments. However, the average daily gains in SCL and SCW were significantly different before and after the attachment of epoxy. The most frequently observed behavior in both adhesive groups was buoyancy, which decreased in frequency after tag attachment in both treatments. Other behaviors, such as scratching, startle responses and underwater movement also exhibited changes after attachment, varying with the type of adhesive used. The study demonstrated that natural adhesive materials serve as an alternative method for attaching satellite tags to rapidly growing juvenile sea turtles, minimizing injury and maintaining flexibility to prevent changes in carapace shape. Overall, the findings suggest the potential for using natural adhesive materials in future satellite tagging efforts to minimize negative impacts on sea turtles.

Synthesis and Characterization of Tricalcium Phosphate as Food Additives Derived from Gastropod (Murex sp.) Shell Waste

Malik Ali-Muhammad, Tatchai Pussayanavin, Chalor Jarusutthirak — Thu, 01 Aug 2024 00:00:00 +0700

The gastropod (Murex sp.) shell is primarily composed of naturally formed calcium carbonate (CaCO₃). This research aimed to utilize CaCO₃ and calcium oxide (CaO) derived from gastropod shell waste for the synthesis of tricalcium phosphate (TCP) as food additives. The study focused on selecting appropriate starting materials and sustainable production processes. Initially, the shell waste was washed and dried before being heated at different temperatures: 300 °C to obtain CaCO₃ and 900 °C to obtain CaO. Subsequently, dicalcium phosphate (DCP) was synthesized by mixing CaCO₃ with phosphoric acid (H₃PO₄) until reaching a pH of 5. Finally, TCP was synthesized using a solid-state reaction method by mixing CaCO₃or CaO with DCP at a ratio of 1:2, then calcining the mixture at 900 °C. All obtained composites, including CaCO₃, CaO, DCP, and TCP (synthesized from two alternative starting materials), were characterized using a total organic carbon (TOC) analyzer, Fourier transform infrared spectrometer (FT-IR), X-ray fluorescence spectrometer (XRF), X-ray diffractometer (XRD), and simultaneous thermogravimetric analyzer (STA). The results indicated the presence of the desired substances. Life cycle assessment (LCA) was used as a tool to compare the environmental impacts of TCP synthesis using two alternative materials derived from gastropod shell waste. The results proved that TCP synthesized from CaCO₃ exhibited more sustainable production processes and lower environmental impacts than TCP synthesized from CaO.

Enhancing Biodiversity and Seagrass Ecosystem Health: Identifying Key Conservation and Restoration Areas in the Bangka Belitung Islands, Indonesia

Okto Supratman, Arthur M Farhaby, Henri , Sigit Febrianto, Wahyu Adi — Thu, 01 Aug 2024 00:00:00 +0700

Seagrass meadows, integral components of global coastal ecosystems, function as biodiversity hotspots and provide essential ecosystem services. Despite their ecological significance, these habitats face increasing threats from anthropogenic activities. This study assesses the species richness and ecological health of seagrass habitats in the Bangka Belitung Islands, Indonesia. We evaluated seagrass coverage, species richness, water transparency, and the cover of epiphytes and macroalgae using the Seagrass Ecology Quality Index (SEQI). Conducted in 2023, our research encompassed nearly all districts within the Bangka Belitung Province that contain seagrass ecosystems. Our findings reveal the presence of 11 out of the 14 seagrass species identified in Indonesia, with an average seagrass coverage of 20.48%±18.10%. Macroalgae and epiphyte coverages were recorded at 1.35%±1.22% and 2.22%±2.58%, respectively. The overall ecosystem health was generally categorized as moderate, with a mean SEQI of 0.68±0.11. Notably, Belitung Regency exhibited the highest SEQI score of 0.77±0.04, categorized as 'Good,' whereas West Bangka Regency had the lowest score at 0.57, categorized as 'Moderate.' Based on these findings, we recommend targeted conservation efforts in areas exhibiting good ecological health and prioritizing restoration initiatives in regions with moderate to poor health. These measures are essential for maintaining ecological balance and ensuring the sustainability of these vital habitats.

Effects of Sodium Bicarbonate Supplements on Growth Performance and Quality of Marine Microalgal Inoculum Production

Wasana Arkronrat, Chonlada Leearam, Rungtiwa Konsantad, Vutthichai Oniam — Thu, 01 Aug 2024 00:00:00 +0700

The effects of sodium bicarbonate (NaHCO₃) supplements (0.05, 0.25, 0.50, 1.0 g·L^-¹) in the culture medium were examined on six marine microalgae inocula cultured under laboratory conditions (25±1 °C, 28 psu, 12L:12D, 3,000 Lux light intensity, Conway medium) for 10 days and compared to a control without NaHCO₃. The parameters assessed included cell density (CD), specific growth rate (µ), division rate (K), and doubling time (D). The results indicated a positive effect on CD, µ, K, and D for the production of Chaetoceros calcitrans, Thalassiosira weissflogii, Chlorella spp., and Nannochloropsis oculata strains with NaHCO₃ additions of 0.25, 1.0, 1.0, and 0.50 g·L^-¹, respectively. Conversely, NaHCO₃ concentrations of 0.25–1.0 g·L^-¹ negatively impacted the CD, µ, K, and D for Tetraselmis suecica and Isochrysis galbana culture. Regarding inoculum quality after refrigerated storage at 4±1 °C, NaHCO₃ supplements did not sustain the growth rates of C. calcitrans, T. weissflogii, and Chlorella spp. inocula cultured after storage for 7, 15, and 30 days. However, 0.5 g·L^-¹ NaHCO₃ maintained the growth rate of N. oculata cultured after storage for 7 days. This study provides comprehensive insights into the optimal NaHCO₃ supplementation for maintaining each microalgal strain in a stable state for inoculum production applications.

Genetic Diversity of Blue Swimming Crab (Portunus pelagicus) from a Crab Bank Project and Wild Crabs in Trang and Krabi Province, Thailand Using mtDNA Control Region Sequences

Thu, 01 Aug 2024 00:00:00 +0700

The blue swimming crab (Portunus pelagicus) is an economically important crustacean with increasing consumption demands, while wild stock is declining. Therefore, a crab bank project has been initiated to restore crab resources. The crab bank, which has been operating for at least 10 years, collects berried females, hatches their eggs to the zoea stage, and release them into the sea. However, the project’s success has not been evaluated. This study investigates the genetic diversity of berried females from the crab bank project and wild crabs in Trang and Krabi provinces. The nucleotide sequences within the mitochondrial DNA control region of P. pelagicus were analyzed. We found that 65.72% of wild crabs in Trang and 39.72% in Krabi shared haplotypes with berried females from the crab bank project. This indicates a division within the P. pelagicus population, forming two distinct groups corresponding to Trang and Krabi. The demographic history analysis suggests a period of population expansion. Based on these genetic diversity findings, we propose management strategies for the crab bank projects in both areas. However, this study is preliminary, and further research incorporating additional genetic markers from the nuclear genome and more samples from areas beyond Trang and Krabi is recommended.

Does Salinity Gradient Affect Distributions of Byssally-attached Bivalves in Songkhla Lake, the Largest Estuary in Thailand?

Nattacha Khanthasimachalerm , Kringpaka Wangkulangkul — Thu, 01 Aug 2024 00:00:00 +0700

Bivalves are typically considered as ecosystem engineers, so knowledge of their distributions is important to understanding the structure of the benthic community in a lagoon system. This study aims to characterize the spatial distribution and examine mechanisms regulating the distribution of Mytilopsis sallei, Mytella strigata and Perna viridis in relation to salinity gradient, which is a key hydrographic feature, in Songkhla Lake, southern Thailand. Surveys showed that M. sallei was abundant in areas upstream with low salinity, while My. strigata were largely found in mid-range salinity. P. viridis was very rare and observed only at the mouth of the lagoon where it connects to the sea. Most M. sallei and My. strigata recruited at salinity conditions similar to where their adults were found. However, only a few recruits and adults of P. viridis was observed in the system, so their spatial relationship could not be evaluated. Results from an experiment testing the effect of different salinity levels on survival, growth, and condition of the bivalves showed that juveniles of M. sallei survived at all salinities (0, 20, 35 psu), while My. strigata and P. viridis survived only at 20 and 35 psu. Our study highlights the role of salinity as a key factor determining distribution of the byssally-attached bivalves in this estuarine system and demonstrates that the degree of influence recruitment and post-recruitment mechanisms have on distributions varies by species. The information obtained is crucial for understanding the dispersal mechanism of alien invasive species that is useful for species management.

Evaluating Neem Seed Powder (Azadirachta indica) as an Anesthetic for Common Carp (Cyprinus carpio) Across Various Weight Groups ‎

Thu, 01 Aug 2024 00:00:00 +0700

A natural alternative anesthetic, such as neem (Azadirachta indica) seed powder, may offer safer and more environmentally friendly practices in aquaculture. This study aims to assess its efficacy and safety on common carp (Cyprinus carpio) across different weight groups. Seven groups of common carp weighing between 20 and 89 g were exposed to neem seed powder. The time required for each fish to attain stage 3 of anesthesia (total loss of equilibrium) and to recover were recorded. The largest group of fish (80–89 g) was selected for subsequent blood tests due to its sensitivity to the anesthetic action of the neem seed powder. The results showed that the lowest-weight fish group (20–29 g) required more time to attain anesthesia at all dosages (12.98–21.13 min) compared to the maximum weight group (80–89 g) (8.83–16.85 min). Recovery times were not significantly impacted by varying anesthetic doses, but shorter recovery times were associated with large fish size. Although neem seed powder at concentration of 5–10 g·L^-1‎ significantly affected blood parameters, such as decreased red blood cell count and increased white blood cell and blood glucose levels, no fish morbidity or mortality was observed. Therefore, neem seed powder (up to 10 g·L^-1) can be safely and effectively used to sedate common carp as an alternative to synthetic chemical anesthetics.

Comparative Analysis of Population Estimates and Habitat Conditions for Three Targeted Parrotfish Species in Sulawesi: Implications for Conservation

Thu, 01 Aug 2024 00:00:00 +0700

One of the functional groups of herbivorous reef fish is parrotfish from the family Scaridae. These fish have been categorized as excavators and scrapers, which enables them to support coral resilience by controlling the algae growth. Unfortunately, some species of parrotfish have been reported as targeted fish and faced uncontrolled fishing. This study aims to estimate the targeted parrotfish population in different locations to discern variations of fish in Sulawesi, and to provide information on the relationship between the fish and their habitat conditions. The study was focused on three species from Buton, Kendari, and Makassar, Scarus dimidiatus, Scarus ghobban, and Scarus niger using UVC and UPT methods to collect the data. The estimated population of fish was reported to be in good condition in Buton, but not in other locations. Moreover, S. ghobban showed a good estimated population among locations, while S. niger in Makassar indicated uncontrolled fishing conditions. The fish were found to prefer locations with more complex benthic substrate compositions, with Buton being the most populated location compared to Makassar and Kendari. Furthermore, fleshy seaweed was correlated with the biomass of S. ghobban. The sea surface temperature (SST) was related to chlorophyll-a and indicated a connection to benthic substrate consumed by the fish, which contributed to the abundance and occurrence of parrotfish in Sulawesi

A Case Study on Mud Spiny Lobster (Panulirus polyphagus Herbst, 1793) Farming in Sea Cages: Insights from Farmers in Southern Thailand

Vutthichai Oniam, Rungtiwa Konsantad, Wasana Arkronrat, Chonlada Leearam — Thu, 01 Aug 2024 00:00:00 +0700

Currently, marine crustacean aquaculture production is high in Asia; however, mud spiny lobster (Panulirus polyphagus) production has been slow. Therefore, gaining more knowledge about mud spiny lobster farming and cultivation management is imperative. This study aimed to bridge this knowledge gap by investigating farmers' activities and environmental factors related to farming, focusing on their impact on mud spiny lobster growth and utilization. The study was conducted in 3 locations, namely Ban Chong Lad, Ban Khao Thong, and Ao Nao areas in southern Thailand from April 2022 to February 2023. The study revealed that three spiny lobster species were cultured in these areas. Panulirus ornatus had the highest percentage, followed by P. polyphagus, with Panulirus vesicolor being the least common. The supply chain started with wild seed procurement from collectors, with juveniles cultured in sea cages for 3–5 months for P. polyphagus or over a year for P. ornatus and P. vesicolor. Most lobsters were sold live to Thai and foreign tourists. The growth monitoring of P. polyphagus revealed a significant impact of density on growth. Lobsters in Ao Nao, which were stocked at lower density, had higher body weight and growth rate compared to those in Ban Khao Thong and Ban Chong Lad. Notably, regular supplementation with fresh mussels seemed to promote better growth in Ao Nao. Meanwhile, water quality parameters (salinity, pH, dissolved oxygen, and temperature) did not appear to affect the growth of this lobster species across areas. This information provides valuable insights for optimizing mud spiny lobster cultivation practices in sea cages.

Crab Biodiversity in Coral Reefs around Mu Koh Tao, Thailand, and the Role of Coral Crabs as Indicators of Habitat Loss Caused by Coral Bleaching

Thu, 01 Aug 2024 00:00:00 +0700

Coral reefs provide ideal habitats for crabs and various living organisms, offering crevices, sandy bottoms, and a rich diversity of resources. Mu Koh Tao, located on the western Gulf of Thailand, boasts vibrant coral reefs and potentially high crab biodiversity. However, coral bleaching due to climate change may impact this biodiversity. This study investigates the diversity, abundance, distribution, and community structure of crabs in coral reefs around Koh Tao and Koh Nang Yuan, including 11 sampling stations with varying levels of coral bleaching. A total of 47 crab species from 34 genera and 14 families were identified. The most abundant and notable species were Trapezia cymodoce, Tetralia nigrolineata, and Tetralia rubridactyla. Additionally, two species were newly recorded in the Gulf of Thailand, and seven species were potentially first reports for Thailand. Rare species dominated, comprising 82.98% of the total. Shark Island had the highest Shannon-diversity and species richness indices, at 2.43 and 5.53, respectively, underscoring its ecological importance. The crab community structure varied with the severity of coral bleaching and the diversity of associated organisms. An in-depth study compared the abundance of coral crabs in healthy versus bleached corals, revealing that Tr. cymodoce did not inhabit bleached Pocillopora damicornis, while Te. nigrolineata was found in both healthy and bleached Acropora hyacinthus, with densities of 23.81 and 7.24 individuals per square meter, respectively. These findings suggest that coral crabs can serve as indicators of climate change-induced coral bleaching and associated habitat loss, highlighting the need for conservation efforts to protect these ecosystems.

Assessment of Lead and Mercury Contamination in Amphidromous Goby Larvae (Nike), Water Quality, and Associated Human Health Risks in Bone Estuary, Indonesia

Abdul Hafidz Olii, Miftahul Khair Kadim, Nuralim Pasisingi — Thu, 01 Aug 2024 00:00:00 +0700

The high market demand for Nike fish as a food source necessitates attention to the sustainability of natural resources and food safety. This study aimed to determine the concentrations of lead (Pb) and mercury (Hg) in Nike fish, assess the water quality of their habitat, and evaluate potential health risks to consumers. Sampling was conducted in September 2022 and July 2023 at three stations along the downstream and estuary of the Bone watershed. Atomic absorption spectrophotometry was utilized to measure the heavy metal concentrations in 250 fish samples. Water parameters were analyzed using principal component analysis (PCA) to explore their relationship with the heavy metals A hazard index analysis was employed to estimate potential health risks to humans consuming the fish. The results revealed that heavy metal concentrations in Nike fish were low: Pb ranged from 0.0019 to 0.0060 ppm and Hg ranged from 0.0013 to 0.0036 ppm. A significant difference (p<0.05) in Pb concentrations among the sampling sites was observed, whereas Hg concentrations showed no statistically significant difference (p≥0.05) between site 1 and sites 2 and 3. Water quality assessments indicated pollution levels ranging from clean to moderately polluted. Human health risk evaluations through total hazard quotient (8.9×10^-4 for Pb, 2.7×10^-2 for Hg) and hazard index analyses (2.8×10^-2for total metals) confirmed that the levels of heavy metals in Nike fish from the Bone Estuary pose no significant risk to human health. These findings confirm the safety of consuming Nike fish, supporting its continued use as a valuable food resource in the Bone watershed.

Effects of Mixed Mineral Supplementation in On-Farm Feeds on the Metamorphosis Development and Growth Performances of Frog (Hoplobatrachus rugulosus) Tadpoles

Thu, 01 Aug 2024 00:00:00 +0700

The frog (Hoplobatrachus rugulosus) is widely cultured in Asian countries. Tadepoles in these cultures are prone to diseases and sensitive to environmental factors, but their metamorphosis and growth may be enhanced by applying minerals. Therefore, this study was conducted to determine the influence of mixed mineral supplementation in on-farm feeds on the metamorphosis development, growth performance, and production cost of H. rugulosus tadpoles. Four levels of mixed mineral supplementation (0%, 0.2%, 0.4%, and 0.6%) were fed to groups of 500 tadpoles stocked in cement ponds. Tadpoles were fed experimental feeds at 5% of their body weight for 35 days. The 0.2% supplementation group showed significantly greater average weight gain (3.84±0.15 g·tadpole^-1) and survival rate (81.00±0.47%) compared to the 0.6% and 0% groups (p<0.05), but was comparable (p>0.05) to the 0.4% group. Notably, other growth parameters (average daily weight gain, specific growth rate, and feed conversion ratio) did not differ significantly (p>0.05) among treatments. The groups receiving mineral supplementation showed significantly (p<0.05) higher average forelimb length than the control from day 20 until day 28, but not from days 30 to 36. Conversely, mineral supplementation did not affect hindlimb length throughout the experiment. Tadpoles receiving 0.2% supplementation completed metamorphosis faster than other groups, starting on day 26 and reaching 100% completion by day 34. This study demonstrated that feeding 0.2% mixed mineral supplementation to frog tadpoles accelerated the metamorphosis and improved their growth, albeit with a slight increase in production costs.