Dinh V. Khuong*

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,*

1. Department of Marine Science, Kulliyyah of Science, International Islamic University Malaysia, 25200 Kuantan Pahang
2. Institute of Oceanography and Maritime Studies (INOCEM), International Islamic University Malaysia, Cherok Paloh, Pahang

3 Pusat Pengajian Sains Ukur dan Geomatik, Univerisiti Teknologi Mara (Perlis), Kampus Arau, 02600 Arau, Perlis.

4. Department of Construction Management, Universiti Malaysia Pahang, 26600 Pekan, 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

METAGENOMICS ANALYSIS OF BACTERIAL DIVERSITY FROM THE

WATER AND SLUDGE OF THE PAHANG RIVER

Nadia Sabrina Afandi¹, Firdaus-Nawi,¹M.*,  Najatul Su Ad Abdullah¹, Rimatulhana Ramly²

¹Fisheries and Aquaculture Research Laboratory (FARLAB), Department of Marine Science, Kulliyyah of Science, International Islamic University Malaysia, Bandar Indera Mahkota, 25200 Kuantan, Pahang, Malaysia.

²Fisheries Research Institute (National Fish Health Research Division – NaFisH), 11960 Batu Maung, Penang, Malaysia.

Corresponding author: firdausn@iium.edu.my 

Various environmental analyses have considered the metagenomics approach for the last  decade due to the recent advancements enabling rapid assessment of  the environment. Hence, there are endless metagenomics applications in studying microbes in an environment,  especially in monitoring water quality, pollution, and identifying harmful pathogens in a river  system. The current status of the metagenomics study done in the rivers of Malaysia is limited. Therefore, the purpose of this study is to evaluate the bacterial diversity and abundance in the water and sludge of the infamous Pahang River while correlating it with the river’s water quality. Water and  sludge  samples  were collected from  five  fish cages  in  April 2022. Each fish farm was selected from five districts in Pahang; Pekan, Bera, Temerloh, Jerantut and Kuala Lipis. Genomic DNA were extracted from the samples and then sequenced  for 16SrRNA. Results from the generated sequences were classified into core microbiome according to the Operational Taxonomic Unit (OTUs). Principle Coordinate Analysis (PCA) reported a sharing of similarities in the microbial composition from two districts, Jerantut and Kuala Lipis. Besides that, this study also found the most predominant phyla were Cyanobacteria, Proteobacteria and Actinobacteria as they are common to be found in river samples. The high abundance of Cyanobacteria may have been due to the presence of an increase in algae accumulation at the fish farms, especially during the hot season and higher nutrients in the river water.

Keywords: Metagenomics, river, Malaysia, abundance, bacteria

BLUE ECONOMY: VALUING CARBON POTENTIAL IN OYSTER AQUACULTURE

Vu Van Sang*, Cao Truong Giang, Vu Van In, Wayne O’Connor, and Sarah C. Ugalde

Research Institute for Aquaculture No.1 Dinh Bang, Tu Son, Bac Ninh Vietnam

vvsang@ria1.org

Oyster aquaculture in Vietnam is relatively new but has proven highly successful. Conservative estimates of production are 15,000 tonnes/annum, and farming has now spread across 28 Provinces with 2,500 coastal-dwelling families benefiting from the industry (O’Connor et al., 2019). These small-scale businesses in rural Vietnam have been supported through a series of investments from Australian Centre for International Agricultural Research (ACIAR) that have promoted profitable and sustainable use of coastal and near- shore resources. This industry has enabled diversification into other types of farming and created more jobs, more assets, more protein sources, and improved quality of life for farmers and their families, but these benefits have also come with challenges (Pierce, 2014). In 2017, Vietnam was ranked 6^th in the world for countries most affected by climate change according to Germanwatch’s Global Climate Risk Index. Therefore, the sustainability and ongoing success of oyster production and aquaculture practices in Vietnam is highly vulnerable to the effects of climate change. Oysters could be a potential tool to help mitigate the effects of climate change due to the carbon trapped in their calcium carbonate shells. But oysters also respire, meaning that the overall carbon footprint of oysters remains unclear.

There exists an opportunity to rapidly advance and sophisticate oyster aquaculture in Vietnam by exploring the full economic potential that has environmental and social benefits.

A survey and supply chain analysis (in press) were conducted on the industry – from farm to plate – in northern Vietnam. The analysis identified key challenges for the new and growing industry (figure below) and areas to improve efficiency to make the supply chain more profitable. 68% of survey respondents thought that oyster shells should be sold as a by- product, and seven potential uses were identified: 1) carbon and carbon off-set schemes, 2) hatcheries for spat production, 3) mineral supplements in livestock feed, 4) soil management to reduce acidity, 5) crop and vegetable growth and vitality, 6) building foundations, road manufacture, or artificial stone, and 6) water filtration and purification. This presentation will discuss the status and challenges of the growing industry and tease apart the supply chain to show areas for improved efficiency. The potential for oyster by-products will be discussed, including the potential for carbon off-set schemes in Vietnam.

HOVEN’S CARP Leptobarbus hovenii REMODELLED GILL PHENOTYPIC TO COPE WITH CLIMATE CHANGE SCENARIO

 Hon Jung Liew¹*, Suhaini Mohamad¹, Sharifah Rahmah^1,2

 ¹ Higher Institution Centre of Excellence (HICOE), Institute of Tropical Aquaculture and Fisheries, Universiti Malaysia Terengganu, 21030 Kuala Nerus Terengganu

²Faculty of Fisheries and Food Science, Universiti Malaysia Terengganu, 21030 Kuala Nerus Terengganu

 *Corresponding author: honjung@umt.edu.my

Climate change is known to negatively impact all levels of aquatic organisms. As an ammonotelic fishes, abiotic factors fluctuation will alter biological processes of fishes, specifically multifunctional gills to support basal metabolism needs and osmotic balancing. The plasticity mechanism underlying this scenario still remain to be investigate especially freshwater species. Therefore, the objective of this study was to investigate the effect of temperature (28 vs. 32°C) and pH (7.0 vs. 5.0) on the gill phenotypic plasticity and physiological responses of Hoven's carp. Fishes were conditioned to (i) 28°C + pH 7 (N_28°C ); (ii) 32°C + pH 7 (N_32°C ); (iii) 28°C + pH 5 (L_28°C) and (iv) 32°C + pH 5 (L_32°C) for 20 days followed by osmorespiration assay. Fishes exposed to interactive high temperature and low pH resulted severe plasticity on the primary, secondary lamellae and cells within lamellae with an increasing trend on the proportion available for gas exchange. Phenotypically, symptoms such as aneurysm, oedema, hypertrophy, curling of secondary lamellae, epithelial lifting, hyperplasia and lamellae fusion were noticed. This condition also induced Hoven’s carp high metabolic oxygen intake and ammonia excretion to about 2x higher, while maintained plasma electrolytes at relatively stable by adjusting plasma osmolarity. This study revealed that Hoven’s carp remodelled their gill phenotypic plasticity to compensate basal metabolism needs under environmental changes condition.

Keywords: climate change, gill, osmorespiration, physiology, energy, teleost

STUDY OF HEAVY METALS BIOACCUMULATION MERCURY (Hg) AND TIN (Sn) IN TRADITIONAL SEAWEED (Caulerpa racemosa) CULTIVATION AT BRONDONG, LAMONGAN

Sapto Andriyono², R. Dimar Herfano Akbar¹, Nina Nurmalia Dewi³, Boedi Setya Rahardja ³, Lailatul Lutfiyah ², Luthfiana Aprilianita Sari³

¹Study of Aquaculture Program, Faculty of Fisheries and Marine, Universitas Airlangga, Kampus C Jl. Mulyorejo, Surabaya 60115, East Java Province, Indonesia

²Department of Marine, Faculty of Fisheries and Marine, Universitas Airlangga, Kampus C Jl. Mulyorejo, Surabaya 60115, East Java Province, Indonesia

³ Department of Aquaculture, Faculty of Fisheries and Marine, Universitas Airlangga, Kampus C Jl. Mulyorejo, Surabaya 60115, East Java Province, Indonesia

^*Corresponding author: sapto.andriyono@fpk.unair.ac.id 

Pollution of the coastal and marine environment is caused by waste from anthropogenic activities or activities on land and in the ocean. Coastal areas in the Brondong area, Lamongan, there are several activities such as capture fisheries, ports, shipping, and residential areas. Heavy contamination can accumulates on aquatic environment and organism, such as Caulerpa racemosa. This study aims to determine the concentration of metals and the value of bioconcentration factors (BCF) and geoaccumulation index (Igeo) of mercury (Hg) and tin (Sn) weight in pond media (sediment) and C. Racemosa seaweed in Brondong, Lamongan. Sampling of  C. racemosa was carried out traditional seawater pond commodities of cantang grouper and seaweed. Heavy metals in seaweed (ramuli, stolon, rhizoid) and sediment samples were measured to determine the heavy metal concentration. Heavy metals were analyzed by a spectrophotometric method using Inductively Coupled Plasma Mass Spectrophotometer.  This results showed that heavy metal concentrations content of mercury (Hg) and tin (sn) in  C. racemosa is low in locations with value of BCF and Igeo <1 close to settlements. Meanwhile, in sediment samples, Hg is not detected, but Sn is detected in a medium concentration about 2.10 ppm (^mg_/kg).

Keywords: Marine ecosystem, ICP-MS, Heavy Metal, Marine Pollution, Caulerpa racemosa, Mercury, Tin