THE DEVELOPMENT AND VALIDATION OF A LENGTH-BASED HARVEST CONTROL RULE TO MANAGE DATA-POOR FISHERIES

 Kanno Hayato^1*, Matsuishi Takashi Fritz¹

 ¹Hokkaido University, 3-1-1 Minato, Hakodate, Hokkaido 041-8611, Japan

^*Corresponding author: h.kanno@fish.hokudai.ac.jp

Effective fisheries management is essential for global food security. However, due to data limitations, conventional management methods, using catch-at-age models to provide management advice on fishing pressure, cannot be applied to most of the world's fisheries. This study aims to develop length-based harvest control rules that require limited data but can ensure sustainable use of fisheries resources as an alternative to conventional management methods. A fishing simulation was conducted using an age-structured population dynamics model, assuming no capacity to control fishing pressure but can control the size-selectivity of fishing. The simulation consists of pre-management and management periods. Fishing pressure was assumed constant throughout both periods, and three levels (low, medium, and high) were tested. In the pre-management period, the length at first capture was set at a small value (0.4 times the maximum length of fish stocks, ). In the management period, three management targets on (0.67, 0.76, and 0.86) were tested, setting  to approach each target value linearly from the pre-management value (i.e., 0.4). The will be changed gradually to mitigate sudden change. The speeds of changing the was varied arbitrarily. The performance of each scenario was assessed from the stock biomass and the catch during the management period. Regardless of the level of fishing pressure, setting the larger improved the stock status but decreased catches in the short term. Long-term sustainable catches could be maximized by setting to 0.86 under medium and high fishing pressure and 0.76 under low fishing pressure. Furthermore, it was found that the stock status could be restored while avoiding the short-term loss in catches by slowly increasing . These results suggested that length-based rules, the simplest fisheries management, can achieve biological sustainability with acceptable levels of short-term economic loss.

Keywords: data-poor fisheries, fisheries management, harvest control rule, length-based management, size selectivity

A COMPARISON OF CATCH EFFICIENCY AND BYCATCH REDUCTION OF TUNA POLE-AND-LINE FISHERIES USING JAPAN TUNA HOOK (JT-HOOK) AND CIRCLE-SHAPED HOOK (C-HOOK)

Khanh Q. Nguyen^A,B,* Binh V. Nguyen^A,C, Huyen T. Phan^A, Luong T. Nguyen^A, Phuong V. To^A and Hao V. Tran^A

Nha Trang University, 2 Nguyen Dinh Chieu, Nha Trang City, Khanh Hoa Province, Vietnam

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

Unwanted bycatch of sea turtles in the tuna fisheries is a global challenge. To evaluate whether the incidental catch of sea turtles could be reduced through changes in fishing gear, this study compared catch rates and bycatch in the tuna pole-and-line with the addition of above-water lights (PL) fisheries using a Japan tuna hook (JT-hook) and a circle-shaped hook (C-hook). There were two phases to this study. First, five PL fishing vessels that used traditional JT-hooks were compared with five PL fishing vessels that used circle-shaped hooks throughout 1 full year of fishing. Results showed that C-hooks significantly reduced bycatch of sea turtle, while negligibly increasing the catch of yellowfin (Thunnus albacares) and bigeye (Thunnus obesus) tuna. Second, we conducted the onboard research to investigate the effect of JT-hook v. C-hook on the catch rates of commercial PL fishery. Results showed that there were higher catch rates of long snouted lancefish (Alepisaurus ferox) and wahoo (Acanthocybium solandri), but lower catches of thresher shark (Alopias spp.) on C-hooks, with no significant differences for other species considered. Our results suggest that the use of C-hooks in the PL fishery is beneficial to protected endangered sea turtle species.

Keywords: bycatch mitigation, circle hooks, conservation, ecological benefit, handlines, hook effect, sea turtle, tuna fishery, Vietnamese fisheries.

ICHTHYOFAUNA OF SETIU WETLANDS, TERENGGANU, MALAYSIA AND ITS ADJACENT MARINE WATER.

 Noorhani Syahida Kasim¹. Siti Azizah Mohd Nor¹. Nuralif Fakhrullah Mohd Nur². Danial Hariz Zainal Abidin³. Masazurah A. Rahim⁴. Noorul Azliana Jamaludin⁵. Tun Nurul Aimi Mat Jaafar²*

¹Institute of Marine Biotechnology, Universiti Malaysia Terengganu, 21030 Kuala Terengganu, Terengganu, Malaysia.

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

³Centre for Global Sustainability Studies, Universiti Sains Malaysia, 11800, Penang, Malaysia.

⁴Fisheries Research Institute, Batu Maung, 11960, Penang, Malaysia

⁵Fisheries Research Institute, Perak, 32000, Malaysia

^*Corresponding author: tun_aimi@umt.edu.my 

The largest wetland system in Malaysia, the Setiu Wetlands, is located on the east coast of Peninsular Malaysia. This wetland supports major ecosystems of marine, fresh, and brackish waters. There are nine interrelated habitats namely marine, beach, mudflat, lagoon, estuary, river, islands, coastline, and mangrove forests that make up this natural environment, which make up the wetland basin with 23,000 ha of land and 880 ha of water. These habitats all have distinctive, complicated physical settings that support their respective biological entities. The majority of the natural resources from the Setiu Wetlands are essential in supporting the livelihoods of the locals. Despite its importance, few studies have been conducted to assess its aquatic biodiversity. In this study, we surveyed the fish diversity of the Setiu wetland and its adjacent marine waters, as well as a small segment of its freshwater habitat. Our checklist accounts for 117 fish species that belonged to two classes, 27 orders, 53 families, and 84 genera. The richest order is Perciformes, with 27 recorded species, representing 22.5% of the alpha diversity, followed by Gobiiformes with 16 recorded species, or 13.3%, and Siluriformes with 15 recorded species, or 12.5% of the diversity. All specimens examined are catalogued and deposited in a local museum collection. The fish checklist presented here represents a step forward in the management and conservation of fish diversity of the newly gazetted Setiu Wetlands State Park.

Keywords: Mangrove, Setiu Wetland, fish diversity, fish inventory

Dose movement of cultured substraTUM effect on the biomass of Green Caviar Seaweed, Caulerpa lentillifera (Chlorophyceae)?

 Manthana Donnoklai^1,2, Rapeeporn Ruangchuay*^1,2, Saweit Chaimongkol¹, Nuttapong Bovornruangroj¹

¹Department of Agricultural and Fishery Science, Faculty of Science and Technology, Prince of Songkla University, Pattani 94000, Thailand.

² Discipline of Excellence (DoE) in Sustainable Aquaculture, Prince of Songkla University, Songkhla 90110 Thailand

^*Corresponding author: ^:rapeeporn.r@psu.ac.th

The green seaweed, Caulerpa lentillifera or sea grape or green caviar has a high economic value. The aim of this study was to instigate new cultured techniques for the high production. Cultured substratum frames were made of PVC pipe with 0.3 × 0.3 m² and were put with two layer of a honeycomb plastic plates. The seedling of the seaweed was used at 150 g per frame or 1.7 kg m^-2. The frame was put to culture in 100-L cylindrical plastics tanks with 50 cm high of water level. The substratum frame was placed at 30 cm high from the tank bottom. The frame was turned back to another side in four treatments of every 0, 1, 2, 4 weeks within 8 weeks of culture period. The culture condition was done at salinity 27 ppt, the maximal light intensity approximately at 600 μmol photon m^-2S^-1 in hatchery with modified Gillard’s medium and aeration. The frames were weighed every week. Thirty branches of the algal ramulus were random to measure the length at the final week of culture. According to the results, inversion of cultured frame in every 4 weeks provided highest biomass. The inversions of the cultured substrate provided a bigger size of ramulus than that of no inversion of substratum frame. The number of ramulus seemed to be the opposite relationship with the size of the ramulus. Culture of sea grape, C. lentillifera should not disturb the cultured substratum.

Keywords: Caulerpa lentillifera, green caviar, sea grape, tank culture

Towards Building Sustainability of a COMMUNITY Managed Mangrove Protected Area in the Verde Island Passage, Philippines

Mario A. Cudiamat^1,2,*

¹College of Arts and Sciences, University of the Philippines Los Baños, Laguna, Philippines

²Pangasinan State University Open University System, Binmaley Center, Pangasinan, Philippines

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

Community-based marine protected area (CBMPA) is a biodiversity conservation approach to manage, restore and rehabilitate marine and coastal resources. Calatagan Mangrove Forest Conservation Park (CMFCP) is a 13-year old mangrove protected area in Western Batangas managed by a group of community stakeholders called Pro-mangrove Alliance and Implementing Team and Arm as Kilitisan’s Advocates of Nature (PALITAKAN). Sustainability of this locally managed MPA remains a challenge to the stakeholders due to socio-economic and institutional factors affecting its management in the past. This study evaluated the effectiveness of the management of the CBMPA in Calatagan, Batangas - a Verde Island Passage corridor, using the harmonized MPA Management Effectiveness Assessment Tool (MEAT) to shed light on the drivers affecting the management towards sustainability. Mixed method approach using appreciative inquiry (focus group discussion and key informant interview) and survey questionnaire were utilized in the gathering of data. The results showed an MPA MEAT score of 71 which means that the management is at Level 4. But, it did not satisfy all the thresholds (enforcement) in Level 4. Therefore, the resulting level of management is Level 3 which means that the CBMPA is sustained already. However, financing, enforcement and monitoring and evaluation (M & E) are still considered as management issues and challenges towards sustainability. Hence, strengthening the community participation, livelihood diversification and building of partnership must be considered in coastal resources management planning at the municipal level.

Keywords: mangroves, community management, conservation, MPA MEAT, sustainable development