Baseline Surveys in PrachuapKhiri Khan and Chumphon Provinces

Although the number of fishing boats registered by trawls has continuously decreased during last decades, the demersal fish stocks are in declining state. Closed area in the Upper Western Gulf of Thailand, including PrachuapKhiri Khan and Chumphon Province, has been effective almost 30 years. However, it seems that it is not sufficient to sustain fisheries resources. Several issues demonstrating the decadence of fisheries resources have been discussed. Huge amount of trash fish, overfishing, lower CPUE and sub-adult economic fish being caught are all sign that management actions are needed. Enlargement of cod-end mesh size is a possible management measure to restore the resources and to ensure sustainable fisheries in the country

Evolution of fish and shellfish supplies originating from wild fisheries in Thailand between 1995 and 2015

Fisheries resources play a crucial role in economic development, food security, and healthy nutrition for humans. Consequently, fisheries are of paramount importance for several Sustainable Development Goals, in particular SDGs 1 and 8, which are related to poverty and economic growth, as well as SDGs 2 and 3, which are about zero hunger and good health. On the other hand, fisheries can also negatively influence the ecosystem (SDG 14, life below water). Thailand is one of the world’s most significant producers and exporters of fisheries products. This present work describes the evolution of wild fisheries production in Thailand for over twenty years and discusses its impact on fish and shellfish supplies. The present overview uses mainly the official statistical catch data of Thailand. From 1995 to 2015, Thailand’s marine fisheries production gradually decreased from approximately 2.8 million tonnes to 1.3 million tonnes per year. Concerning taxonomic composition of the catches, no dramatic shifts were recorded during the 20-year period. The main observation seems that for less abundant taxa, such as Chirocentridae, Sillaginidae, Ariidae, Sharks, and Psettodidae, their part in the catch was halved between 1995 and 2015. On the other hand, inland capture fisheries remained constant at 0.2 million tonnes per year. The annual value of wild fisheries production was, on average US$1.7 billion. Notably, trawl fishing systematically reduced during these two decennia, resulting in a fishing efficiency of approximately 140 tonnes of demersal fish per trawl unit per year in 2015. During 2008–2015, the number of registered gill net fishing boats drastically increased from 2,300 to 6,600, and this has led to a dramatic decline in fishing efficiency to about 10% in 2014–2015. More in general, Thailand’s continuous decline in marine capture production was linked to increased fuel prices, tightening restrictions by neighbouring countries for access into their exclusive economic zone, and the depletion of resources due to overfishing and illegal fishing. Against rising concerns about the sustainability of intensive fishing practices in recent years, Thailand is ramping up efforts to reduce the exploitation of fishery resources to levels that would achieve maximum sustainable yields. In particular, the intensity of fishing based on gill nets needs to be addressed in the future. Hence, Thailand’s fisheries production faces the pressure of realising the importance of sustainable fisheries resources management and its impact on marine life and biodiversity, in addition to its role as a significant food source for a healthy population

Fisheries Resources in PrachuapKhiri Khan and Chumphon Province, Thailand

From June 2013 - May 2014, a study of fisheries resources and commercial trawlers operating in the locality of Prachuap Khiri Khan and Chumphon Provinces was conducted by collecting data from small-sized otter board trawls (<14 m overall length; OBT1), medium-sized otter board trawls (14 – 18 m overall length; OBT2) and pair trawls (PT).Catch data were also collected from landing sites at Prachuap Khiri Khan and Chumphon fishing ports The results show that catch per unit effort (CPUE) for OBT1, OBT2 and PT were48kg, 28kg and 150kg, per hour respectively. The proportions of food fish and trash fish in the catch were calculated as 36:64%, 58:42%. In the food fish group, demersal fish along withs shrimp and prawn were the main components of the OBT1accounting for86% of the total ‘food fish’ catch Demersal fish and cephalopods were the main components of OBT2accounting for77%of the total food fish catch and pelagic and demersal fish were the main components of PT accounting for83% of the total food fish catch Juveniles of economically important species were found in high percentages of 78%, 64% and 74% respectively in the trash fish catches from these trawlers. The sizes of the economically important species were analyzed and it was found that the mean lengths of most species were smaller than their predicted size at first maturity, particularly for pelagic and demersal species. Length analysis also showed that most individuals of the economically important species caught were smaller than their size at first maturity. Lizardfishes, purple-spotted bigeye, lattice monocle bream and short mackerel were the main species of concern, in terms of the numbers of undersized fish caught. However, length analysis of squid showed a high percentage of individuals at a mature size. Unless adequate management measures are introduced effectively, the present situation of unsustainable harvesting of fisheries resources from trawlers will continue, leading to further declines in fish catches and fish catch quality

Review of the Trawl Fisheries in Prachuap Khiri Khan and Chumphon Province, Thailand

Although the number of fishing boats registered by trawls has continuously decreased during last decades, the demersal fish stocks are in declining state. Closed area in the Upper Western Gulf of Thailand, including Prachuap Khiri Khan and Chumphon Province, has been effective almost 30 years. However, it seems that it is not sufficient to sustain fisheries resources. Several issues demonstrating the decline of fisheries resources have been discussed in this paper. Huge amount of trash fish, overfishing, lower CPUE and sub-adult economic fish being caught are all signs that strong management actions are strongly needed. Enlargement of cod-end mesh size is a possible management measure to restore the resources and to ensure sustainable fisheries in the country

Review of the Marine Fisheries in Trat Province, Thailand

There is a large number of fishing gear used and a high level of species diversity in Trat water. However, fisheries resource status in this area is in declining state. Sizes of some economic species caught also showed a critical status which are smaller than the spawner sizes (size at first mature). CPUE of research vessel trawl continuously declined. As a result, several research papers revealed that fishing effort should be reduced to optimize MSY and MEY levels. Consequently, effective fisheries management measures are urgently needed. Limit fishing in area and season closure is an alternative measure to protect the juveniles, spawners and habitats from several kinds of gear especially for trawl fisheries, which has successfully been implemented in the Upper Western Gulf of Thailand (covered Prachuab Kiri Khan-Chumphon-Surat Thani provinces) and has being performed in the Inner Gulf of Thailand in May 2014

Fisheries Resources in Trat Province, Thailand “Strategies for Trawl Fisheries Bycatch Management”

This study of fisheries resources in the Trat Province (Thailand) was conducted during January to December 2014 by collecting the data from commercial fishing vessels landings at fishing ports in the Province. It was found that the catch per unit of effort(CPUE) of Thai Purse Seine(TPS), Light luring Purse Seine(LPS), Anchovy Purse Seine(APS) and Anchovy falling net (AFN) fisheries were 3,825, 5,859, 2,949 and 685 kg/day respectively. Short mackerel and gold stripe sardinella formed the highest composition of the catch from TPS and LPS while anchovies were the main component of APS and AFN. The CPUE of otter board trawl (OBT) was calculated as 23.7 kg/hour comprising of 15.1 kg of food fish (63.8% of the total catch) and 8.6 kg trash fish(36.2% of the total catch). Threadfin bream was the major species making up 7.95% of the total food fish weight. In the trash fish group, juveniles of economic fish accounted for 40.4% of the catch, whereas the remaining 9.6% was made up of true trash fish. Pony fishes made up the highest composition (46%) of the trash fish catch. Size measurements of 13 economically important species suggested that the mean length of three pelagic species were larger than the size at first maturity while the other ten species were smaller than size at first maturity. There is evidence that effective management measures are urgently needed to prevent recruitment overfishing which may lead to a further decline of fisheries resources. More effective management of high-efficiency fishing in some seasons and areas should be considered to conserve fisheries resources and their sustainable use for the future

Trawl Catch Composition and Quantity in Prachuap Khiri Khan and Chumphon Province, Thailand

Data on catch composition and quantity was collected from small (<14 m; OBT1) and medium-sized (14–18 m; OBT2) otter board trawlers (OB) and from pair trawlers (PT) landing at Prachuap Khiri Khan and Chumphon fishing ports during June 2013 - May 2014. The catch per unit of effort (CPUE) of OBT1, OBT2 and PT was 48, 28 and 150 kg/hour, respectively. The proportion of food fish to trash fish was 36:64, 58:42 and 46:54, respectively. Demersal fish, along with shrimp and prawn, were the main component of food fish in OBT1, summing up to 86% of the total food fish. Demersal fish and cephalopods were the main food fish component in OBT2, summing up to 77%. Pelagic fish and demersal fish were the main food fish component in PT, summing up 83%. In trash fish group, juveniles of economically important species showed high percentages (64-78%) in all three trawl types. In general, the average length of economically important species was smaller than their size at first maturity. In particular, Lizard fishes, purple-spotted bigeye, lattice monocle bream and short mackerel are of concern because of small size of fish caught. There is an apparent risk of overfishing for these species. Squid species caught by the trawlers showed higher percentage of mature size of individuals. Improved management is required to reduce the unsustainable harvest of fisheries resources by the trawler fleet in the region

Effectiveness of Adaptive Real-Time Closures for Managing Migratory Species in Data-Limited Multispecies Fisheries

Fixed closure (FC) is a standard fisheries management tool for protecting sensitive species or species requiring conservation. However, an FC might not effectively manage migratory species because of the large uncertainties of their migration. Adaptive real-time closure (ARTC) is a tool that updates closure areas according to the latest information. This study aimed to evaluate the effectiveness of ARTC to conserve sensitive species for data-limited fisheries by a series of simulations using migration models with hotspots. In the single species simulation, the conservation ratio for the sensitive species in FC varies widely at greater migration uncertainty. In ARTC, a longer duration of a hotspot resulted in a higher conservation ratio. When the mean duration of hotspots was medium or long, the conservation ratio for the sensitive species was more than 50 % in more than 99 % of the simulation trials. In multispecies fisheries, a clear trade-off was observed between the conservation ratio of sensitive species and other species. ARTC was more effective than whole closure when the proportion of sensitive species was high or without closure when the proportion was low. Conditions in which ARTC was most appropriate were described for hotspot duration, increased numbers of individuals in a hotspot, and the relative value of conservation, representing the ratio of the value of conserving sensitive species to one of catching other species

Simulations of fixed closure and real-time closure to manage migratory fish species for data-limited fisheries

Fisheries closure has been used as a fisheries management tool to protect species that need to be conserved. A commonly used type is fixed closure (FC), which specifies the closure area and period in advance and does not change after that decision is made. It has been claimed that FC is not effective for the management of migratory species, because it is difficult for FC to respond to uncertainties in the predicted distribution of species. Recently, real-time closure (RTC) has been introduced to address this issue. However, the use of RTC is still limited, because its benefits compared with FC have not been evaluated sufficiently. In this study, we conducted simple simulations to evaluate the efficiency of RTC to respond to uncertainties in the movement of migratory species. In terms of the protection of migratory species, the mean performance index of RTC was generally higher than that of FC, and the mean performance index of FC tended to decrease with greater uncertainty of species movement. We also estimated the extent of the reduction of the closure period by applying RTC instead of FC. The results of this study indicate that RTC is an efficient method of fisheries closure, and provide quantitative information to guide the use of RTC instead of FC