THE EFFECT OF SEDIMENT REMOVAL TIME ON SEDIMENT QUALITY OF NILE TILAPIA NURSERY POND

 Wudtisin. I^1*, Pichitkul. P¹, Sirisuay. S¹, ¹Paankhao. N

 ¹Faculty of Fisheries, Kasetsart University, Bangkok, Thailand

^*Corresponding author: idsariya.w@ku.th

Pond preparation is always essential for earthen pond farmers to reduce the risk of poor bottom soil qualities. Bottom soil or sediment relates to pond water quality and affects fish yield. In addition, sediment deposition occurs continuously underneath the pond due to the accumulation of dead organisms, uneaten feed, and fish feces. The sediment degradation by microbial activity under anoxic condition can generate reduced substance such as hydrogen sulfide to the water column. The sediment removal between crops is one of the farmer practices. The suitable time interval to remove sediment depends on the quality of the residue sediment after harvest. This research aims to determine the proper interval time to remove sediment in the tilapia nursing ponds. Each pond was stocked with 600,000–800,000 individual sex reversal Nile tilapia (Oreochromis niloticus) per pond. Fish were raised in the suspended net cage hanging in the pond (10,000-12,000 fish/cage). Each pond has different sediment removal times. Sediment removal took place at three-year intervals for each pond.Sediment in the pond, namely C3, was removed in the early of the year 2022, while sediment in C2 was removed in year 2021, and sediment deposition in C1 was removed in year 2020. The ponds were dried approximately 1-2 weeks after sediment removal. The sediment was compositely sampled from each tilapia nursing pond. The basic water quality indicators in three ponds were measured, reporting in dissolved oxygen, pH, conductivity, salinity, total dissolved solids, turbidity, nitrite, nitrate, total ammonia and orthophosphate, ranging from 3.3-5.3 mg/L, 6.4-6.9, 178-301 µs/cm, 0.1-0.2 ppt, 119-202 mg/L, 19-35 NTU, 0.006-0.018 mg/L N, 0.022-0.055 mg/L N, 0.409-0.558 mg/L N, and 0.041-0.094 mg/L P, respectively. The sediment from each pond was triplicately analyzed and statistically tested. The sediment pH among ponds did not differ statistically (p>0.05). The sediment pH from all ponds was slightly acidic, ranging 6.73-6.78. The organic matter percentage from C1 was the highest and significantly different from C3 (P<0.05). The percentage of sediment water content, sediment nitrite, and sediment nitrate from C1 also differ statistically from C2 and C3 (P<0.05). Total ammonia in sediment was significantly lowest in C3, with an average of 3.34 + 0.15 mg N/Kg dry sediment. Orthophosphate in sediment has a similar trend to total ammonia deposition. The concentration of orthophosphate accumulated in the pond bottom was 0.042 + 0.002 mg P/Kg dry sediment, of which C3 had the lowest concentration. The correlation of the sediment indices was investigated. The percentage of water content in sediment was highly related to sediment nitrate (r = 0.881, P< 0.01). The percentage of organic matter accumulated in the bottom pond has a high relationship with nutrients in sediment; nitrite (r=0.752, P<0.05), total ammonia (r=0.758, P<0.05), and orthophosphate (r=0.700, P<0.05). The optimum organic matter percentage for aquacultural ponds was 1-3, and the optimum pond soil pH ranged 7.5-8.5 recommended by Boyd et al. (1998) and Boyd et al. (2002). This finding can be summarized that the organic matter and sediment pH from all ponds was unsuitable. Although the latest sediment removal pond was in early this year, the concentration of the organic matter was still out of the optimum range. The concentration of organic matter increases with time. The high accumulation of organic matter is related to anoxic conditions beneath the water. The overall sediment qualities between ponds C2 and C3 were similar, while the sediment qualities in C1 differed from the other two ponds due to sediment removal last in year 2020. The sediment removal time interval might be considered to change from a 3-year interval to a 2-year interval. The additional practices during pond preparation should be considered carefully. The proper amount of lime application is necessary. Lime requirement calculation should be applied.

Keywords: Sediment removal, Sediment quality, Nile Tilapia

MACROZOOBENTHOS DIVERSITY AS WATER QUALITY BIOINDICATOR IN BEDOG STREAM YOGYAKARTA

Titian Ukhuwah Imanniah¹, Namastra Probosunu^1*, Eko Setyobudi ¹, Djumanto¹

¹Fisheries Department, Faculty of Agriculture, Universitas Gadjah Mada, Flora Street, Bulaksumur, Yogyakarta, Indonesia

*Corresponding author: probosunu@ugm.ac.id

Bedog Stream was located in Special Region of Yogyakarta that passes through the Sleman Regency and Bantul Regency. This research aimed to know the diversity and abundance of macrozoobenthos and to know water quality in Bedog Stream. This research was conducted during September–October 2020 in Bedog Stream. Data were collected eight times in 6 stations. Macrozoobenthos samples were collected using Surber net, then preserved using formalin 4%. Ecological indexes analyzed were macrozoobenthos abundace, diversity, dominance, and evenness. Water quality measured were water temperature, flow velocity, Total Suspended Solid (TSS), depth, pH, dissolved oxygen, free carbon dioxide, and organic matter. The results showed 26 species with macrozoobenthos abundace ranged from 42–521 individual/m². The macrozoobenthos that commonly found was Sulcospira testudinaria. Substrate type at six stations consist of rocks, sand, and mud; water temperature ranged from 27.7–28.6℃; flow velocity 0.61–0.7 m/second; TSS 282.08–290.42 mg/L; and depth 15.37–24.74 cm. Result measured of pH ranged from 6.27–6.6; dissolved oxygen 4–6.61 ppm; free carbondioxide 8.67–12.13 ppm; and organic matter 4.74–16.57 ppm. The diversity of macrozoobenthos was 1.28 with a moderate category. The water conditions of Bedog Stream have a balanced ecosystem with moderate ecological pressure. Water quality parameter affect the abundance of macrozoobenthos. 

Key words: Abundance, Bedog Stream, Diversity, Macrozoobenthos

WATER QUALITY STATUS OF BEDOG STREAM YOGYAKARTA BASED ON THE POLLUTION INDEX

Bernardino Enrico Pradipta¹, Namastra Probosunu^1*, Riza Yuliratno Setiawan¹, Tony Budi Satriyo¹

¹Fisheries Department, Faculty of Agriculture, Universitas Gadjah Mada, Flora Street, Bulaksumur, Yogyakarta, Indonesia

*Corresponding author: probosunu@ugm.ac.id

Bedog Stream Yogyakarta is often used for household, industrial, agricultural irrigation, farm, and bathing and washing latrines activities. Changes in land use and fuction along the border have resulted in decreased the water quality in Bedog Stream. This study aims to determine the status ofthe water quality of Bedog Stream, Yogyakarta in terms of its pollution index value. The research was carried out in Sleman Regency and Bantul Regency which was divided into six stations from September to October 2020. The parameters observed in this study were water temperature, total suspended solids (TSS), total dissolved solids (TDS), dissolved oxygen (DO), biological oxygen demand (BOD), pH, and ammonia (NH3). The results showed that the water temperature at the observation station ranged from 27.7-28.6^oC, TSS ranged from 282.08-290. 42 mg/L, TDS ranged from 187.38-313.63, DO ranged from 4.02-6.61 mg/L, BOD5 ranged from 4.02-6.61 mg/L, BOD5 ranged from 2.76-4.29 mg/L, pH ranged from 6.29-6.62, and ammonia ranged from 0.0002125- 0.000225 mg/L. The pollution index value is calculated by entering the results of observations of the water quality parameters into the pollution index equation in accordance with the Decree of the Minister of Environment No. 115 of 2003. The results showed that the pollution index value of Bedog River ranged from 3.472-3.554, these results indicate that Bedog Stream is in lightly polluted status.

Keywords: Pollution index, Bedog Stream, Water quality, Water quality standards

PERFORMANCE OF TOP-WATER FISHING LURES IN RECREATIONAL FISHING OF Channa striata (BLOCH, 1793) IN MALAYSIA

 Azriel David Lian Raja, Izharuddin Shah Kamaruddin*

Department of Aquaculture, Faculty of Agriculture, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia

^*Corresponding author: izharuddin@upm.edu.my

Recreational fishing is a type of fishing activity that utilizing fishing rod, hook, and line to catch fish. The main purpose is to obtain recreation, and the catch is not intended for food (subsistence fishing) and not for income generation (commercial fishing). Recreational fishing activity contributed to the country’s economy and the social well-being of the people. The development of ‘artificial fishing lures’ contributes significantly to the development of recreational fishing activities, where ‘top-water fishing lure’ is one of it. There are four types of top-water fishing lures utilized by recreational anglers in Malaysia. This includes popper, pencil, buzzbait, and frog imitation lures. Debates arise among anglers about strike performance of each type of lure on Channa striata (striped snakehead). The C. striata is a carnivorous-freshwater-species and widely distributed throughout Malaysia. The species can be found in lake, pond, disused mining pool, river system, ditch, and even in paddy field. Most newcomer anglers having difficulties in deciding the best fishing lure to use. Also, scientific research related to fishing lures in the country is currently lacking. Thus, this study will be conducted to identify the performance of top-water fishing lures for C. striata in Malaysia. The study will be conducted at three sampling locations within the campus area of Universiti Putra Malaysia. These locations are ponds, which generally abandoned and undisturbed, due to their hidden location and no fishing zone regulation. The performance of the lures will be measured by recording the number of strikes and fish landings. The length (cm) and weight (g) of all fish caught will be measured, to explore any possible relationship between different types of lures and strike rate (%) of fish. The results of the study should reveal the best top-water fishing lure for C. striata. This study should provide some invaluable information about the performance of top-water fishing lures, for a better recreational fishing management, in Malaysia.

Keywords: Recreational fishing, Artificial lure, Top-water fishing lure, Channa striata

EFFECTS OF ARTEMIA AND TILAPIA DENSITY ON THE ABILITY TO TREAT ORGANIC MATTER IN WASTEWATER FROM WHITE LEG SHRIMPS     (Litopenaeus vannamei) FARMING

Hong T B Truong^1* Huy Đ Nguyen¹

¹Cam Ranh Centre for Tropical Marine Research and Aquaculture, Institute of Aquaculture, Nha Trang University, No 2 Nguyen Dinh Chieu Street, Nha Trang City, Viet Nam

^* Corresponding author: hongttb@ntu.edu.vn

White leg shrimp (Litopenaeus vannamei) farming effluent contains pollutants that include high levels of total suspended solid (TSS), chemical oxygen demand (COD) and growth promoting substances. This study investigated on ability of Artemia and Tilapia (Oreochrois niloticus) to treat organic matter in wastewater shrimp farming. The analytical results of input factors showed that total suspended solid (TSS) in bottom of wastewater from shrimp farming was higher than those of values given in QCVN 11: 2008/BTNMT 1.4 times. Both Artemia and Tilapia had the ability to rapidly reduce organic matter content in wastewater of shrimp farming. After the experiment, the biochemical oxygen demand (BOD₅), chemical oxygen demand (COD), total suspended solid (TSS) met effluent standards in 44/2010/TT-BNNPTNT and QCVN 11: 2008/BTNMT in all of the investigated plots. In surface of wastewater from shrimp farming, TSS, BOD₅, COD and total Coliforms were lowest 6.2 ± 1.1 mg.l^-1, 3.9 ± 0.5 mg.l^-1, 8.6 ± 1.4 mg.l^-1, 1.7.10² (MPN/100ml) in the treatment of 300 Artemia individuals.l^-1 , respectively. In bottom of wastewater from shrimp farming, TSS, BOD₅, COD and total Coliforms were lowest 21.4 ± 5.1 mg.l^-1, 8.5 ± 1.5 mg.l^-1, 11.6 ± 3.6 mg.l^-1, 28 (MPN/100ml) in the treatment of 16 Tilapia individuals.m^-3, respectively.

Keyword: Artemia, Shrimp farming, Suspended solid, Tilapia, Wastewater.

FISHING TECHNIQUES OF GULAMAH (ARGYROSOMUS AMOYENSIS BLEEKER, 1863) USING GADHOK NETS (BOTTOM GILLNET) IN BANTUL REGENCY BEACH

Suwarman

Departement of Fisheries Gadjah Mada University

Gadhok nets are fishing gear types of bottom gillnet nets used by fishermen in Bantul Regency to catch gulamah (croakers). This study aims to examine and determine the construction and operating techniques of catching croakers using gadhok and to find out the fishing area of croakers in the waters of Bantul Regency. This research uses observation and interview methods. The gadhok net has a play number of 80, a webbing thread diameter of 0.15 mm, a mesh size of 8 inches, a span length of 103.53 m, and a span height of 8.52 m. The number of mesh sizes towards the length of 510 mesh holes and towards the width of 42 mesh holes. The top and float rope length is 58.7 m each with a rope diameter of 7.1 mm. The length of the bottom and ballast ropes is 67.5 m with a rope diameter of 2.8 mm. The hanging ratio value is 61%, while the average shortening value is 39%. The net depth is 6.76 m, and the net area when operated is 426.52 m2 . The net operation starts from preparing supplies, boat engines, and fuel then the fishermen go to the fishing ground for the setting process. The distance between the fishing ground and the fishing landing is ± 2 km. After the setting is complete, the net is left for 24 hours in the water, and then the net is lifted to the ship. The hauling process begins by lifting the sign buoys and anchors, and then the net is pulled slowly onto the boat. Fishermen innovate using relatively new fishing gear in the form of gadhok nets to catch croakers with high economic value.

Key words: Bantul Regency, gill nets, mesh size, net contruction

EFFECTS OF DIFFERENT TYPES OF FISH TAGS ON SURVIVAL RATE AND TAG RETENTION OF Pangasius nasutus

 Amirul Irfan Ahmad Rafee, Izharuddin Shah Kamaruddin*, Aziz Arshad

Department of Aquaculture, Faculty of Agriculture, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia

^*Corresponding author: izharuddin@upm.edu.my

Fish tagging is a detection technique employed to gather data and information about fisheries resources in natural and man-made water bodies globally. Fish tagging is useful for fisheries managers and fisheries scientists to understand fish migratory patterns, conducting fish stocking program, measuring growth rate, determining population abundance, and elucidating escaped farm fish. In Malaysia, scientific studies related to fish tags and tagging technique have not been widely explored. Therefore, this study tries to understand the effects of different types of fish tags on survival rate and tag retention of Pangasius nasutus. Pangasius nasutus is a highly valuable native fish species, and its availability depends solely on wild population, especially from major Malaysian river systems. Pangasius nasutus is currently categorized as ‘moderately threatened’ which is linked to overharvesting. Due to this, fish tagging utilization holds the potential to obtain new data and information about P. nasutus. Four treatments with three replications of each treatment, will be developed as an experimental design of the study. The juvenile of P. nasutus will be tagged with three types of fish tags, which include dart tag (Hallprint), t-bar tag (Hallprint) and customized t-bar tag (customized). One treatment will not be applied with any tag, as control. The fishes will be fed twice daily, ad libitum. The survival rate and the tag retention rate will be counted and recorded daily, for a total of three month of rearing period. Water quality parameters will also be measured, which include dissolved oxygen (mg/L), temperature (°C), pH, and total ammonia (mg/L). Statistically, survival rates and tag retention rates of different types of tags will be compared to find any significant results (p<0.05) using one-way ANOVA. It is expected that one of the tags will hold as the optimize results of the study, which suggest the most suitable tag to be applied for P. nasutus. This is especially for future works related to fish stocking program and migratory pattern of P. nasutus. 

Keywords: Fish tagging, Tag retention, Pangasius nasutus

STATUS OF COASTAL TRAWL FISHERIES UNDER CLIMATE CHANGE IN SOC TRANG PROVINCE, THE LOWER MEKONG DELTA, VIETNAM

Nguyen Trung Tin¹*, Vo Le Khanh Quynh¹, Mai Van Hieu¹, Vo Thanh Toan¹ and Ha Phuoc Hung¹

¹Department of Fisheries Management and Economics, College of Agriculture and Fisheries, Can Tho University, Vietnam.

*Corresponding author: nttin1795@gmail.com

Status of coastal trawl fisheries under changed climate in Soc Trang province, the lower Mekong delta, Vietnam was performed from January 2018 to January 2020. Results showed that, average boat power, length, and tonnage was 39.9±18.8 HP×boat^-1; 12.16±1.11 m×boat^-1; and 5.63±2.94 t×boat^-1, respectively. Average cod-end mesh-size was 21.2±7.0 mm. Average number of on-boat fishers was 2.98±0.95 fisher×boat^-1 (70.58 % was family member); averaged labor ages was 45.7±11.2 years old; fishers’ education rate was low (77.5% under secondary school). Main fishing season was from April to July annually. Average catches was 9.3±6.2 t×boats^-1×year^-1. Average total of fixed costs was 5,364±2,727 USD∙boat^-1 (87 % for boat, 13 % for fishing gear). Average gross income was 12,727±6,227 USD∙year^-1∙boat^-1. Average total costs was 9,591±5,000 USD∙year^-1∙boat^-1. Average profit was 3,136±2,000 USD∙year^-1∙boat^-1. Average rate of return was 0.33±0.4 times.  Decreased catches was due to by overfishing (42 % fishers agreed); and by climate change (40 % fishers agreed). Only 72.5% fishers have known climate change but not good solutions to cope with them. Soc Trang coastal trawl fisheries with small mesh size at cod-end destroyed coastal fishery resources so it should be controlled in a very strict manner.

Key words: climate change, coastal fisheries, Soc Trang province, trawl

SEAWEED FARMING: MOVING FORWARD TO SUSTAINABILITY

 Jonalyn P. Mateo^1,2*, Joseph P. Faisan, Jr³., Rema C. Sibonga², Iona Campbell⁴, Elizabeth Cottier-Cook⁴, Victor Marco Emmanuel N. Ferriols², Maria Rovilla J. Luhan²,

Anicia Q. Hurtado²

¹Institute of Marine Fisheries and Oceanology, University of the Philippines Visayas Miagao, Philippines 5023

²Institute of Aquaculture, University of the Philippines Visayas Miagao, Philippines 5023 ³Aquaculture Department, Sputheast Asian Fisheries Development Center, 5021 Tigbauan, Iloilo, Philippines 5021

²Scottish Association for Marine Science (SAMS), Scottish Marine Institute, Oban, United Kingdom

*Corresponding author: jpmateo@up.edu.ph

For more than five decades already, seaweed has been one of the major aquatic organism farmed in the Philippines. Different culture techniques have been practiced and innovated in the grow out to increase production, resiliency to diseases, pests, and changes in the environmental conditions, and increase carrageenan quality. Though different culture techniques have been introduced, most still use tie-ties (soft straws). Globally, microplastic pollution has been a problem. Studies revealed that seaweed can be a good source of bioplastics, however, the need to innovate culture techniques should be done to secure and sustain the seaweed industry. This study aimed to determine the growth performance, pests and diseases occurrence, and carrageenan quality of Kappaphcyus alvarezii using different tie-tie materials, a. soft straws and b. black twine. Seaweed was farmed in Brgy. Pedada, Ajuy, Iloilo in three replicates for four runs using different tie-ties. Carrageenan quality was measured every run. Results showed that there was no significant difference between the growth rate of seaweeds in the three runs, though, in the last run seaweed grown with black twine as material had higher growth rate though negative. Carrageenan quality (yield, viscosity, and gel strength) also did not show significant differences between the two different tie-tie materials. Though the prices of these two different materials differed by more than $2.00, black twine could be used longer than soft tie-ties. Therefore, this study recommends the change of tie-tie material (from soft straws to black twine) to reduce plastic pollution contributed by the seaweed industry for future food security and sustainability.

Keywords: Kappaphycus sp., farming, sustainability

STOMACH CONTENTS OF WILD Pangasius nasutus (BLEEKER 1863) (PATIN BUAH) IN PAHANG RIVER, MALAYSIA

 Ming Ying Goh¹, Izharuddin Shah Kamaruddin²*, Aziz Arshad^1,2, Rumeaida Mat Piah³

¹International Institute of Aquaculture and Aquatic Sciences, Universiti Putra Malaysia, 70150 Port Dickson, Negeri Sembilan, Malaysia

²Department of Aquaculture, Faculty of Agriculture, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia

³Faculty of Fisheries and Food Science, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia

^*Corresponding author: izharuddin@upm.edu.my

Pangasius nasutus (local name patin buah) is one of the most sought-after and tasty fish that can be found along the stretch of Pahang River, Malaysia. The price of wild caught fish could fetch up to USD40.00 per kilogram. However, little is known about the food and feeding habits of the species, and information about it in scientific literature is scarce. To address this issue, a study of stomach content of P. nasutus was conducted to identify the food items consumed by the species in Jerantut area of Pahang River, Malaysia. This is also to understand the seasonal variation in the diet composition of the species. A total of 82 fish samples were collected monthly from January to June 2022. The stomach contents were identified under dissecting and compound microscopes and were quantified following the relative-fullness method. Later, the food items were classified into eight groups. Results indicated that detritus had the highest value in relative abundance (33.03%), and this were followed by fruit remains (21.16%), fish remains (14.73%), molluscs (11.74%), crustaceans (8.01%), plant debris (5.10%), unidentified materials (4.56%) and lastly sand grains (1.66%). For monthly variation, results indicated that detritus is relatively the most abundantly recorded in the month of January, March and June, with 36.14%, 60.00% and 62.71% respectively. Meanwhile, fruit remains present entirely in the month of February (100.00%) and more than half in May (59.20%). During April however, only trace/unidentified materials are present (100%). In general, the findings indicated that the food items found in the stomach contents of P. nasutus comprise of a wide range of animal and plant-based food items. This confirmed that P. nasutus is an omnivorous species. The information obtained in this study is useful for the fisheries managers to further conserve and protect the P. nasutus species in Pahang River, Malaysia.

Keywords: Stomach contents, Food items, Pangasius nasutus, Pahang River

DISTRIBUTION OF ORIENTAL ANGELWING CLAMS PHOLAS ORIENTALIS (GMELIN 1791) IN WESTERN VISAYAS, PHILIPPINES

 Anne Brigette Ledesma^1*, Tabitha Anne Famatid^1,2, Harold Monteclaro²

¹Institute of Fisheries Policy and Development Studies, College of Fisheries and Ocean Sciences, University of the Philippines Visayas, Miagao, Iloilo, Philippines 5023

² Institute of Marine Fisheries and Oceanology, College of Fisheries and Ocean Sciences, University of the Philippines Visayas, Miagao, Iloilo, Philippines 5023

^*Corresponding author: abledesma@up.edu.ph

The oriental angelwing clams Pholas orientalis (Gmelin 1791) are considered one of the highly-prized commodities in the Philippines. It has increasingly gained demand for human consumption across the country; however, excessive harvesting has caused serious depletion of the resource. This paper identifies the production areas of P. orientalis, locally known as ‘diwal’ in the country. Results showed that based on the primary (i.e., surveys, key interviews, and focus group discussions) and secondary (i.e., government reports, published papers) data gathered, P. orientalis is endemic in Western Visayas region, Philippines. Three out of six provinces in the region were confirmed to be the traditional breeding grounds of P. orientalis: 1) Capiz, 2) Iloilo, and 3) Negros Occidental. Active occurrences were recorded along the coasts in the northeastern portion of Capiz, eastern Iloilo, and central Negros Occidental. Available information from secondary data sources has also identified Aklan province as natural habitat of P. orientalis however, the natural stocks in the area have become extinct due to overfishing. The lack of updated information on the major sources of the high-valued P. orientalis in the region is needed to be addressed to provide more reliable and accurate records on the utilization of the resource. In addition, the exploitation of P. orientalis remains a concern due to the absence of culture technology and persistent illegal harvesting. The management and conservation of P. orientalis fishery, as well as the practices and dynamics affecting the sustainability of the resource, and the well-being of key actors in P. orientalis production chain are discussed, providing a comprehensive status of the angelwing clam resource in Western Visayas region.

Keywords: angelwing clams, endemic, fisheries resource management, sustainability

THE GOVERNANCE OF ANGELWING CLAM FISHERY IN WESTERN VISAYAS, PHILIPPINES

 Anne Brigette B. Ledesma, Tabitha Anne G. Famatid, Harold M. Monteclaro*

College of Fisheries and Ocean Sciences, University of the Philippines Visayas, Miagao, 5023 Iloilo, Philippines

^*Corresponding author: hmmonteclaro@up.edu.ph

The Oriental angelwing clams Pholas orientalis are important and sought-after shellfishes renowned for its sweet and delicate taste. Endemic in the western central region of the Philippines, production was severely affected by adverse climatic conditions and high consumer demand that led to indiscriminate harvesting. The fishery had been historically plagued with cycles of boom and busts as well as stories of recovery and/or resurgence, thus, local fishery officials have devised various strategies purportedly to manage the resource. This study therefore evaluated the socio-political processes in the fishery through focus group discussions and key informant interviews. Results showed that the governance of the angelwing clam fishery is varied according to fishing ground. In many areas, local chief executives strongly influence decisions on fishing period, start of harvest, allowable catch, and number of fishers. Such protocols may or may not be formal. Local policies or legislations related to the angelwing fishery may or may not have sound basis. In some areas, the presence of formal policies may not necessarily translate to proper implementation. In other areas, trade may even be regulated thereby restricting access to markets and fair price. Nevertheless, many local harvesters appear to comply with the arrangements set by local leaders with a belief that such are necessary to properly manage the resource. Results of this study provide relevant information towards the sustainable management of angelwing clams in the Philippines.

Keywords: Angelwing clams, Fisheries institutions, Local governments, Sustainability

PRIVATE SECTOR ENGAGEMENT TO COMBAT IUU FISHING: THE CASE STUDY OF VIETNAM TUNA FISHERIES

Tran Van Hao¹, Nguyen Huu Thanh¹, Pham Khanh Thuy Anh¹, Nguyen Thi Nghiem Thuy¹, Nguyen Huu Huy Hoang², Nguyen Van Binh² and Stephen Fisher³

¹Nha Trang University (NTU)

² Vietnam Tuna Association (VINATUNA)

³ Sea Delight Company – International Seafood buyers

Private sectors play key roles on the tuna supply chains in Vietnam, especially on inputting fishery information for fishery management & transparency purposes to combat IUU fishing. Vietnam tuna fisheries have engaged private sectors in the whole tuna supply chain including fishing communities, purchasing system (local middleman), tuna processor community as well as international buyers to involve on combating IUU fishing by digitalized key data elements (KDEs) on fishery information. The digitalization is separated into each key actor in the tuna supply chains: eLogbook system for fishers, trace-code application for processors, eCDS for authorities as well as a fisher-based data collection application (COPPA) as an independent observer database.

Key words: IUU Fishing, Vietnam tuna fisheries, private sectors

STATUS OF COASTAL GILLNET FISHERIES AND FISHERS’ AWARENESS ON CLIMATE CHANGE IN THE BAC LIEU PROVINCE, VIETNAM

 Ha Phuoc Hung¹*, Vo Le Khanh Quynh¹, Mai Van Hieu¹, Vo Thanh Toan¹ and Nguyen Trung Tin¹

¹Department of Fisheries Management and Economics, College of Agriculture and Fisheries, Can Tho University, Vietnam.

*Corresponding author: hphung@ctu.edu.vn

Status of coastal gillnet fisheries and fishers’ awareness on climate change in the Bac Lieu province, Vietnam, was studied during the period March, 2018 to January, 2020. Results of study revealed that the structure characteristics of gillnetters and fishing gear were as followed: average onboard engine (26.30±14.54 HP); average gillnet lengths, heights, and mesh sizes were 3613.1±2269.3 m; 3.59±1.86 m; and 53.4±15.5 mm, respectively. Average number of onboard fishers was 3.65±1.42 person×boat^-1. Captured fisheries scale was artisanal and small-scale. Fisher’s education rate was low (75% of unlettered and primary). Average captured fisheries time was 9.3±3.11 month×year^-1. Average catches was 4.44±2.21 t×year^-1. Of 52 fishes, 26 families and 10 orders was collected by gillnet. Decreased catches were by overfishing (100% fishers believed); and by climate change (47.5%). The fixed cost for gillnetters was 5,955±3,364 USD∙boat^-1 (63 % for boat, 37 % for fishing gears). Gross income was 12,727±5,318 USD∙year^-1∙boat^-1. Total costs was 8,364±4,227 USD∙year^-1∙boat^-1. Profit was 4,364±3,409 USD∙year^-1∙boat^-1. Rate of return was 0.52±0.8 times. Of 62.5% fishers has awakened manifests of climate change, and having solutions temporary to cope with. Need to synchronous solutions to protect fishery resources and develop coastal gillnet fishing in area.

Key words: Bac Lieu province, climate change, coastal fishing, gillnet

STATUS OF COASTAL STOW-NET FISHERIES UNDER CLIMATE CHANGE IN SOC TRANG PROVINCE, THE LOWER MEKONG DELTA, VIETNAM

 Vo Thanh Toan ¹*, Vo Le Khanh Quynh¹, Mai Van Hieu¹, Nguyen Trung Tin¹ and Ha Phuoc Hung¹

¹Department of Fisheries Management and Economics, College of Agriculture and Fisheries, Can Tho University, Vietnam.

*Corresponding author: vttoan@ctu.edu.vn

Studying on status of coastal stow-net fisheries under changed climate in Soc Trang province, the lower Mekong delta, Vietnam was performed from January, 2018 to January, 2020. Results showed that, average boat power, length, and tonnage 32.7±13.9 HP×boat^-1; 12.09±1.63 m×boat^-1; and 5.46±3.97 t×boat^-1, respectively. Stow-net average length, width, height, and cod-end mesh-size were 23.3±7.97 m; 14.2±5.02 m; 5.35±2.71 m; and 12.7±0.46 mm, respectively. Average labor numbers was 3.63±1.56 fisher×boat^-1; Average labor ages was 47.9±13.7 years old; Fishers’ education rate was low (80.0% for primary school). Main fishing seasons was from January to June annually. Average total invested costs for stow-netters was 5,636±2,455 USD∙boat^-1. Average gross income was 6,409±3,136 USD∙year^-1∙boat^-1. Average total costs was 3,395±2,545 USD∙year^-1∙boat^-1. Average profit was 1,773±1,000 USD∙year^-1∙boat^-1. Average rate of return was 0.52±0.4 times. 45% fishers having some aware of climate change, and having some temporary solutions to cope with climate change. Generally, stow-net fishing have low catches, fisherers’ income unstably, effected by weather, and under the ban of stow-net fishing, so need to have good synchronous solutions so that their live are stalely

Key words: stow-net, climate change, coastal fishing, Soc Trang province

THE SUCCESS OF ACTIVE MANGROVE RESTORATION EFFORT OF THE PERI-URBAN MANGROVES IN KENYA

 Sirikwa N. Levis¹², Fredrick L.Tamooh³, Muyodi J. Derrick²

1 Campus 2 -Can Tho University (CTU) 3 Thang 2 street Can Tho Vietnam. ²Ceriops Environmental Research Organization.  3Kenyatta University, Mombasa Campus, Department of Zoological Sciences,

*Corresponding authors: tamooh.fredrick@ku.ac.ke : derrick.muyodi@ceriops.org

Mangrove ecosystems support more than 80% of the marine fisheries resource of economic importance. The degradation of these critical marine habitats poses a significant threat to the species diversity of marine fisheries. The rate of degradation of the peri-urban mangrove forest in Kenya is approximately 5% per year. Restoration efforts to regenerate mangroves have been initiated by local community groups adjacent to the mangrove ecosystems. However, these efforts lack a definite tracking model to influence sustainability. This study assessed the success of mangrove restoration efforts at Tudor creek Mombasa, under the Big Ship Community Based Organization. The forest structures of different mangrove forest classes (pristine, degraded, and restored) at a section of Tudor creek were compared. GIS technology was used to assess the degradation scale of the pristine sites. One-way ANOVA analysis showed that there was a significant variation in the forest structures of degraded sites and pristine, and restored sites (P < 0.05). Logging of mature mangrove trees was identified as the main stressor or causative agent for the degraded site. There was a strong and positive correlation (r = 85%) between parent trees' number and the density of naturally regenerated saplings. The high number of tree stumps showed that deforestation is the main cause of the degradation of mangroves at Tudor creek. The study argues that success cannot be measured solemnly on the survival rate of the planted trees. Instead, a sustainable forest management model addressing the livelihood gaps of the adjacent communities should be embraced hence addressing logging as a stressor. Therefore, the study recommended a model which informs sustainable management of mangrove forests, the Adopt-A-Site Model. Similarly, the study recommends a socio-economic study be done in order to quantify and define a suitable financial model for the sustainable active restoration of the mangrove ecosystems.

Keywords: Mangrove Ecosystems, Sustainability, Adopt-A-Site, Restoration, Peri-urban mangroves

ABUNDANCE OF BILLFISH BY-CATCH AND ITS SIZE VARIATION IN THE EAST COAST OF PENINSULAR MALAYSIA

 Mohamed Shahrul Daniel Hamzah ¹, Rashidah Abdul Razak ^1,2, Juliana Mohamed ^1,2, Muhammad Zahir Ramli ^1,2, Muhammad Faiz Pa’suya ³, Rahimi Abdul Rahman ⁴,

Fikriah Faudzi ^1,2, Aimimuliani Adam ^1,2,*

¹Department of Marine Science, Kulliyyah of Science, International Islamic University Malaysia

²Institute of Oceanography and Maritime Studies (INOCEM), International Islamic University Malaysia

³Pusat Pengajian Sains Ukur dan Geomatik, Univerisiti Teknologi Mara

⁴Department of Construction Management, Universiti Malaysia Pahang

^*Corresponding author: aimiadam@iium.edu.my

In Malaysia, billfish is typically not the fisheries primary targets but well recognized in sport fishing. Rompin, Pahang is known for the migration route’s pitstop for billfish, and this migration contribute to the expansion of the local economy by creating vital coastal livelihoods and recreational opportunities. Unfortunately, the drastic reduction of billfish catches since past five years urge for the investigation. Thus this study was carried out to determine the abundance and size variation of the billfish by-catch along the East Coast of Peninsular Malaysia. Samples of billfish were collected at fish landing jetty in Kuantan, Pahang from April 2021 to July 2022. All billfishes collected were identified as Indo-Pacific Sailfish (Istiophorus platypterus) and no other species was observed. Monthly abundance showed that there was an increasing trend from early to middle of the year and suddenly decreased. This trend can be observed in both years of 2021 and 2022. This fluctuated trend was coincided with the catches experienced by the anglers in Rompin waters (from personal conversation). Studies on billfish abundance in Pacific Ocean region showed similar trend and this was linked to the spawning activities which was expected to occur from April to November. With regards to the size composition, monthly variation in size composition showed that large size of sailfish can be observed in 2022 while the smaller size of sailfish was observed in 2022. This size composition indicated that the sailfish found in Pahang waters were composed of juvenile and adult fish (early adult and recently-spawned adult). All these sailfishes were assumed to be in their migration journey from northernly waters (China, Taiwan, and Japan) toward southernly waters (Australia) and stop by along Pahang waters for nursery and feeding. 

Keywords: Billfish, Istiophorus platypterus, diet composition, fishery, conservation

EFFECT OF TANK COLOUR ON DEFORMATION RATE, SKELETON, SALINITY SHOCK AND COLOUR OF JUVENILE GOLDEN TREVALLY GNATHANODON SPECIOSUS UNDER ELEVATED TEMPERATURE

Chau Bich Lien*, Truong Thi Mai Huong, Le Minh Hoang

 Institute of Aquaculture, Nha Trang University, No 2 Nguyen Dinh Chieu Street, Nha Trang City, Vietnam

*Email: lien.cb.60ntts@ntu.edu.vn

The objective of this study was to evaluate the effect of tank color on quality of juvenile golden trevally such as growth, survival rate, respiratory rate and deformation rate reared at elevated temperature. The experiment was arranged with fifteen treatments corresponding to five tank colours (blue, red, yellow, grey, white) reared at three temperature (30, 32, 34℃). Each treatment was repeated three times. The quality properties were assessed after four weeks of rearing. The results showed that tank colour and elevated temperature affected the quality of juvenile golden trevally. Following the tank color as red, yellow, blue, grey and white, the growth and survival rate of fish tend to decrease gradually, but the respiratory rate and deformation rate of fish tend to increase. The growth and survival rate of fish gradually decreased and the respiratory rate and the rate of deformation gradually increased as the temperature increased from 30 to 34℃ at the above tank colours. The combination of tank colour with elevated temperature did not affect the quality of the juvenile. In conclusion, the good quality of juvenile golden trevally can be reared in the condition that the tank colours were red and yellow at the temperature of 30℃.

Keywords: Golden trevally, Gnathanodon speciosus, tank colour, elevated temperature.

GREEN ENERGY PRODUCTION BY MICROALGAE: PHOTOSYSTEM I LIGHT-HARVESTING PROTEINS REGULATE PHOTOSYNTHETIC ELECTRON TRANSFER AND HYDROGEN PRODUCTION.

Thi Thu Hoai Ho¹ , Chris Schwier², Tamar Elman³, Vera Fleuter², Karen Zinzius²,

Martin Scholz² , Iftach Yacoby³ , Felix Buchert²  and Michael Hippler^2,4

¹Faculty of Fisheries, University of Agriculture and Forestry, Hue University, Vietnam

²Institute of Plant Biology and Biotechnology, University of Muenster, Germany

³School of Plant Sciences and Food Security, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Israel

⁴Institute of Plant Science and Resources, Okayama University, Kurashiki, Japan

Green algae, Chlamydomonas reinhardtii, can produce hydrogen (H₂) by the action of hydrogenase. Under anoxic conditions, the photosynthetic electrons are transported through a series of redox reactions to ferredoxin (FD) via linear electron flow (LEF). FD donates electrons to hydrogenase in order to catalyse protons and electrons for H­₂ production. LEF and cyclic electron flow (CEF) compete for electrons transferred from the acceptor side of photosystem I (PSI). Partitioning between LEF and CEF is regulated by proton-gradient regulation 5 (PGR5). There is evidence to suggest that electron partitioning may also be mediated by PSI remodelling processes. The dynamics of the PSI-associated light-harvesting proteins: LHCA2 and LHCA9. These two unique light-harvesting proteins are located on the PSI core at binding sites at the PSAL pole and bound to PSAB between PSAG and PSAH, which are independent of other LHCAs. In this study, the photosynthetic electron transfer and H₂ production in single, double, and triple mutants deficient in PGR5, LHCA2, and LHCA9 were defined. Our results revealed that lhca2 and lhca9 mutants are efficient in photosynthetic electron transfer. Mover, the H₂ photoproduction kinetics indicated that the pgr5/lhca2 and pgr5/lhca9 mutants were significantly different, and the double mutant pgr5/lhca2 is a promising H₂ photo producer. This observed finding highlights the fact that the absence of LHCA2 or LHCA9 impacts H₂ synthesis independently.

Key work: hydrogen production, electron, light harvesting protein,  PSI remodelling.

ESTABLISHING AN ARTIFICIAL REEF SYSTEM MODEL ON NHA TRANG BAY, VIETNAM IN ORDER TO IMPROVE BIODIVERSITY

Vu Nhu Tan ¹*, Nguyen Van Nhuan ¹

¹Institute of Marine science and Fishing technology, Nha Trang University, Vietnam.

*Corresponding author: tanvn@ntu.edu.vn

The artificial reef system model (ARSM) was established in Nha Trang bay, Khanh Hoa province, Vietnam. It covers 15,600 square meters of the seabed. Research data were collected in 12 months by methods of diving with scuba equipments and experimental fishing in order to evaluate the effectiveness of the model for the ability of concentration, protection and development of coastal resources. The results showed that the number and density of species have increase rapidly, including depends on the time, inside the ARSM area, the number of species has increased from 41 to 73 species (65,8%), the density has increased from 917 to 1566 individuals/400m² (1,7 times higher) in transect. The results have also showed that soft corals and algae start growing on artificial reefs.

Key words: artificial reef system model, number of species, soft corals, Nha Trang bay

INNOVATING THE FREEZER HOLDS ONBOARD BY POLYURETHANE (PU) AND COMPOSITE TECHNOLOGY IN ORDER TO IMPROVE FISH QUALITY

Vu Nhu Tan ¹*, Nguyen Van Nhuan ¹

¹Institute of Marine Science and Fishing Technology, Nha Trang University, Vietnam.

*Corresponding author: tanvn@ntu.edu.vn 

Vietnamese fisheries is small-scale, based-on citizens’right fisheries. The fishing vessels is belong to private people. The capture fishery is small. So, the goal of industrialization of the fishing industry is still difficult due to many obstacles. Through a number of previous survey on capture fishery in various coastal province in Vietnam, it was found that preservation of products on board was mainly still using ice which brought from the shore, preservation tools by trays or plastic bags.  The traditional storage tanks onboard were made by woods, Styrofoam, Nylon and PE foam. This lead to poor cold retention. At the same time, the polluted water/fish liquid can easily run/soak into wood/PE foam/Styrofoam. So, microorganism/bacteria/virus can stay and spread out there. After that, microorganism/bacteria inside of tanks can attack/infect the fish, lead to reduce fish quality. To overcome this problem, it is essential to innovate the fish preservation onboard by polyurethane (PU) and composite technology which replace woods, Styrofoam, Nylon and PE foam in order to improve fish quality, ensure seafood safety and hygiene. The project has built 24 models (24 off-shore fishing vessels) of product preservation using PU and Composite materials in 10 coastal provinces of Vietnam. The results show that the PU and composite freezer holds onboard help waterproof, ice efficiency up to 95% (Traditional tunnel is about 60-70%), limit water breakers, prolong fishing time at sea up to 30 days, tunnel life from 15 - 20 years (Traditional cellar 3-4 years), quality preserved products, sold at higher prices, bringing economic efficiency to offshore fishing fleets. It means the fishermen has higher income which contributing to improve the lives of their families. Thanks to the PU and composite technology that adheres to the inside of the ship's hull (wood is less susceptible to water), limiting the ship's breaking water, reducing shipwreck accidents at sea; Increasing the life of the ship's hull also means reducing deforestation for shipbuilding wood, contributing to forest protection and environmental protection.

Key words: polyurethane (PU) technology,  composite technology, freezer holds (tankers), fish quality

GREEN ENERGY PRODUCTION BY MICROALGAE: PHOTOSYSTEM I LIGHT-HARVESTING PROTEINS REGULATE PHOTOSYNTHETIC ELECTRON TRANSFER AND HYDROGEN PRODUCTION.

Thi Thu Hoai Ho¹ , Chris Schwier², Tamar Elman³, Vera Fleuter², Karen Zinzius²,

Martin Scholz² , Iftach Yacoby³ , Felix Buchert²  and Michael Hippler^2,4

¹Faculty of Fisheries, University of Agriculture and Forestry, Hue University, Vietnam

²Institute of Plant Biology and Biotechnology, University of Muenster, Germany

³School of Plant Sciences and Food Security, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Israel

⁴Institute of Plant Science and Resources, Okayama University, Kurashiki, Japan

Green algae, Chlamydomonas reinhardtii, can produce hydrogen (H₂) by the action of hydrogenase. Under anoxic conditions, the photosynthetic electrons are transported through a series of redox reactions to ferredoxin (FD) via linear electron flow (LEF). FD donates electrons to hydrogenase in order to catalyse protons and electrons for H­₂ production. LEF and cyclic electron flow (CEF) compete for electrons transferred from the acceptor side of photosystem I (PSI). Partitioning between LEF and CEF is regulated by proton-gradient regulation 5 (PGR5). There is evidence to suggest that electron partitioning may also be mediated by PSI remodelling processes. The dynamics of the PSI-associated light-harvesting proteins: LHCA2 and LHCA9. These two unique light-harvesting proteins are located on the PSI core at binding sites at the PSAL pole and bound to PSAB between PSAG and PSAH, which are independent of other LHCAs. In this study, the photosynthetic electron transfer and H₂ production in single, double, and triple mutants deficient in PGR5, LHCA2, and LHCA9 were defined. Our results revealed that lhca2 and lhca9 mutants are efficient in photosynthetic electron transfer. Mover, the H₂ photoproduction kinetics indicated that the pgr5/lhca2 and pgr5/lhca9 mutants were significantly different, and the double mutant pgr5/lhca2 is a promising H₂ photo producer. This observed finding highlights the fact that the absence of LHCA2 or LHCA9 impacts H₂ synthesis independently.

Key work: hydrogen production, electron, light harvesting protein,  PSI remodelling.