Aquaculture In Taiwan Research Articles

An analysis on the preliminary benefits of aquaculture smart aeration control

Aquaculture in Taiwan is characterised by high breeding densities of up to five times higher than the normal breeding densities. Pollution in the breeding environment and its adjacent waters have exacerbated the occurrence of disease outbreaks in fish, shrimp and shellfish, which greatly impacted the economy. Therefore, the parameters pertaining to water quality status, especially dissolved oxygen are particularly important. In addition to the rising cost of labour, land, infrastructure and other materials, the capital needed to engage in aquaculture has risen, whereas the profits have decreased. This limits the growth of aquaculture and fisheries. To overcome this problem, it is essential to shift towards efficient and ecologically precise smart aquaculture. The application of industrialised and smart systems in the vertical diffusion and in-depth integration of aquaculture facilitates decision-making, improves the level of intelligence in breeding, and enhance aquaculture's contribution to Taiwan's economy.

Economic Assessment of Meteorological Information Services for Aquaculture in Taiwan

The main purpose of this research was to evaluate and analyze the economic value of the meteorological information services (MIS) provided by the Central Weather Bureau (CWB) when applied to aquaculture in Taiwan. In this research, a contingent valuation method (CVM) was used to inquire about the subjective rating given to the CWB’s meteorological information services based on the responses to a national level questionnaire distributed among aquaculture farmers. The subjective rating revealed how the aquaculture farmers rated the accuracy of the MIS provided by the CWB and how they recognized the impact of the MIS on their aquaculture output. On this basis, this research determined the economic value brought about by the application of the meteorological information services. In order to understand the main factors affecting the respondents’ willingness-to-pay (WTP) for the MIS, this research also conducted an empirical estimation of the bid function. The results indicated that the main factors affecting the WTP were found to include the respondents’ subjective rating of the meteorological information services (including the accuracy rating and the effect rating), traditional social and economic background variables such as income and education level, as well as fish species. In addition, through testing the estimation of the bid function, it was also found that the survey sample used in this research had a significant starting point bias effect, which needed to be corrected using econometric methods. According to the empirical results, the median willingness-to-pay (WTP) of aquaculture farmers in Taiwan was 3544 New Taiwan Dollars (NTD)/person/year and the total economic value at the national level ranged from 157 million to 209 million NTD per year. Since the MIS service users have often lacked sufficient knowledge and ability to interpret the weather forecasts, how to strengthen the capabilities of service users in using MIS through the promotion of training programs and improve the value of the MIS may be an important policy insight.

Simultaneous trace analysis of 10 benzophenone-type ultraviolet filters in fish through liquid chromatography–tandem mass spectrometry

We developed and validated a trace analytical method for the simultaneous determination of 10 benzophenone (BP)-type ultraviolet filters (BPs; BP, BP-1, BP-2, BP-3, BP-8, 2-hydroxybenzophenone [2-OHBP], 4-hydroxybenzophenone [4-OHBP], 4-methylbenzophenone [4-MBP], methyl-2-benzoylbenzoate [M2BB], and 4-benzoylbiphenyl [PBZ]) to analyze BPs in 110 commercial fish samples. The quick, easy, cheap, effective, rugged, and safe (QuEChERS) technique coupled with ultrahigh-performance liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS) was employed. The developed method exhibited satisfactory linearity (R2 > 0.993), favorable precision with intraday and interday relative standard deviation ranges of 1.0%–26.6% and 2.3%–29.3%, respectively, and a limit of detection ranging from 0.001 to 0.1 ng/g. BP and 2-OHBP were detected in 100% of the samples; BP-3, 4-OHBP, PBZ, and 4-MBP were detected in >70% of the samples; M2BB was detected in 33% of the samples, and BP-2 and BP-8 were not detected. Higher mean (minimum–maximum) levels of 2-OHBP and BP were found in fish samples with low lipid content, ranging from 18 (1.1–218.3) to 10 (0.5–45.4) ng/g, and those with high lipid content, ranging from 22 (1.5–76.4) to 9.6 (5.2–18.5) ng/g; low levels of the remaining six BPs were found, ranging from 0.01 to 0.9 ng/g. The mean 2-OHBP levels were 21.3, 14.4, and 30.2 ng/g for fish samples obtained from aquaculture in Taiwan, the wild in Taiwan, and different countries, respectively, with levels up to 218.3 ng/g (field eel) for a sample from Indonesia. BPs may not pose a health risk to Taiwanese adults through the consumption of fish; however, additional studies are needed to examine the risk that these contaminants may pose to ecosystems and human health.

Can Aquaculture Ponds Be Managed as Foraging Habitats for Overwintering Water Birds? An Experimental Approach

Coastal wetlands have been gradually developed by aquaculture and other anthropogenic infrastructure, reducing the habitat for water birds. The traditional operation of shallow-pond milkfish (Chanos chanos) aquaculture in Taiwan may provide a model for aquaculture production that operates in harmony with overwintering water birds. The goal of this study was to test whether experimental water drawdown of aquaculture ponds, following the seasonal, traditional milkfish aquaculture, can create resource pulses that attract water birds in Tainan City in southern Taiwan. This experiment tested four types of aquaculture with potential for application: wild fish, no-feed tilapia, milkfish, and tilapia with feed. Ponds were surveyed every other day for water depth and water birds at least 37 times in four winters after water drawdown. In general, drawdown ponds created resource pulses that attracted higher feeding bird densities and numbers of species than control ponds in all aquaculture types. Milkfish ponds often had higher water birds in each year. Deep waders were sometimes the most abundant guild in the control, whereas shorebirds, shallow and deep waders were often higher in the drawdown treatment. Bird densities and numbers of species were correlated with water level, benthic biomass and water Chl a, but not with tilapia biomass. Species, such as Black-faced Spoonbills (Platalea minor), responded to water levels with the exception of Little Egrets (Egretta garzetta). The operation of seasonal, traditional shallow-pond milkfish aquaculture is suitable for foraging of water birds during the winter migratory bird season.

Improving productivity management of commercial abalone Haliotis diversicolor supertexta and Haliotis discus hannai aquaculture in Taiwan: A bioeconomic analysis

The aquaculture techniques and operating management of production processes can influence the production performance of the overall aquaculture fishery. This study collected biological and economic data through of questionnaires from the production process of Taiwan's abalone culture industry and used the principles of economics and multivariate statistics to analyze the key for the profits of Taiwan's abalone industry. The results showed that the stocking density, production scale, and culture mode influenced the inputs and outputs of the abalone industry. Large-scale polyculture of Haliotis diversicolor supertexta and Haliotis discus hannai had the best profitability. Therefore, farmers who only culture Haliotis diversicolor supertexta are suggested to use polyculture model and moderately increase the stocking density to increase the economic benefit of cultures.

A trading decision support model to maximize the sustainability of a self-financed guaranteed farmgate price program

We study a non-government organization (NGO) program that supports the household livelihood of small farmers by committing to purchase a fixed quantity at a guaranteed farmgate price of a storable agri-product under price fluctuation. Since the World Trade Organization (WTO) disciplines its members to limit and reduce domestic support for the agriculture, storing and trading (selling) the product on the spot market at a favorable price generates revenue to cover the cost of the program. The objective of this study is to develop a stochastic dynamic trading decision model that maximizes the sustainability of the NGO's supporting program, measured as the survival probability, i.e. the probability that the program can continue operating after a predetermined period of time. The results of a numerical study, based on the tilapia aquaculture in Taiwan, show that our model yields higher survival probability (after 4 years) than the profit-maximization policy by close to 10% in average. Moreover, the trading decision optimization is particularly suitable for market environments with high price fluctuation, i.e. the most challenging circumstances for small farmers.

Marine Environmental Management and Development Strategy for Marine Aquaculture in Taiwan: Cobia Case Study

Marine Environmental Management and Development Strategy for Marine Aquaculture in Taiwan: Cobia Case Study

Revealing the compositions of the intestinal microbiota of three Anguillid eel species using 16S rDNA sequencing

Anguilla japonica, A. marmorata and A. bicolor pacifica are important eel species for aquaculture in Taiwan. In the past, seldom studies focused on the intestinal microbiome of them or the probiotics used in their cultivation. Probiotics are microbes that can improve the health of organisms, and the microbes isolated from the intestines of organisms might be the potential probiotics. Therefore, the aim of this study was to collect the intestinal mucus samples of these three eel species for investigating the autochthonous microbiome using 16S rDNA sequencing. The diversity, abundance of the intestinal microbiome and compositions of all the libraries were identified. Moreover, the composition of intestinal microbiome of eel was suggested that it would be affected by the waters and the characteristics of different eel species. Furthermore, most of the identified predominant genera of the intestinal microbiome of these three eel species, such as Cetobacterium, Clostridium, Shewanella, Acinetobacter and Bacteroides, seemed to have great potential as the probiotics. In the future, more studies shall be conducted to promote the practical application of these candidate probiotics for improving the techniques of eel farming.

Spawning segregation and philopatry are major prezygotic barriers in sympatric cryptic Mugil cephalus species

The flathead mullet, Mugil cephalus, is a commercially vital fish in fisheries and aquaculture worldwide. Genetic analyses have recently revealed three cryptic species of M. cephalus in the Northwest Pacific. These species are sympatric in Taiwanese waters and specific reproductive behaviors have been suggested to be a major prezygotic barrier. Species composition was evaluated in samples of M. cephalus at different growth stages collected from various habitats (offshore spawning ground, estuarine nursery and feeding areas) over several months or years. The gonadosomatic index of adults and the body length of juveniles were recorded to determine the reproductive season and recruitment periods in estuaries. The results revealed partially temporal spawning isolation between species pairs, spatial segregation on specific spawning grounds and strong philopatry preclude hybridization. Thus, the results imply that traditional fisheries of mature fish in the Taiwan Strait target only one species, whereas aquaculture in Taiwan contain juveniles of all three species collected in estuaries. The ecological niche and demography of these species must be investigated further to estimate the impact of juvenile sources on aquaculture.

Improving the management of commercial giant mottled eel Anguilla marmorata aquaculture in Taiwan for improved productivity: a bioeconomic analysis

A multivariate statistical analysis was conducted with the aim to identify the key factors affecting the profitability of commercial aquaculture of the giant mottled eel Anguilla marmorata on Taiwan. The results revealed significant differences between the different fish farming systems used on Taiwan in terms of sustainable and profitable commercial enterprise. In terms of production costs, the water circulation systems accounts for the highest costs in water production, and feed costs account for 82.3 % of the total production cost. However, the survival rate is low, about of 20–30 %. Eels were cultured for 2–3 years before a market profit was reached. The farming system in the eastern region of Taiwan had the lowest production cost. The benefit–cost ratio of the concrete pond in the central region of Taiwan and the soil pond in the eastern part of Taiwan was the highest, at about 2.6, and profitability was relatively good; however, the farming cycle is longer and the production risk is higher. These results also show that the survival rate is significantly correlated to production efficiency. Consequently, based on our analysis, we suggest that strengthening cultivation techniques, appropriately increasing stocking density and segmenting glass eels farming in terms of nursery rearing and grow-out will reduce the production risk and enhance the profitability of the industry.

A PRELIMINARY IDENTIFICATION ON EARLY STAGE OF OYSTER LARVAE SOURCE AND DISPERSAL: A FIELD AND NUMERICAL STUDY NEARBY ZHOUSHEI RIVER ESTUARY, TAIWAN

Oyster (Crassostrea angulata) has long been an important species for economic aquaculture in Taiwan. This study was motivated by a recent and emerged problem that the traditional regions where oyster larvae (OL) were collected in the south part of Zhoushei river during the past decades have already changed. Figure 1 depicts our study region with three geophysical features: (1)the biggest industrial park (i.e. Mailiao Industrial Park, MIP) in Taiwan is located at the mouth of Zhoushei river, (2)multiple sandbars exist within shallow-water regions, and (3)a wide range of tidal flats where a well-mixed estuary has been confirmed. We speculate that those factors may give a mixed contribution to water quality, flow structure and biological process, thereby affecting dispersal and connectivity of OL. Unfortunately, a conclusive reason causing the mentioned problem is still unknown. The main goal of this study is to identify where the OL may come from, and what affects the dispersal ranges and recruitment areas during early stages. In this paper, we shall present field and numerical results for a preliminary identification on early stage of OL source and dispersal.

Antimicrobial susceptibility and genetic characterisation of oxytetracycline-resistant Edwardsiella tarda isolated from diseased eels

Edwardsiellosis is one of the most important bacterial diseases in eels. Edwardsiella tarda (E. tarda) isolates (n=94) from diseased eels were screened against the eight most commonly used antimicrobial agents...

Real-Time Quantitative PCR Assay for Monitoring of Nervous Necrosis Virus Infection in Grouper Aquaculture

Viral nervous necrosis caused by nervous necrosis virus (NNV) exacts a high mortality and results in huge economic losses in grouper aquaculture in Taiwan. The present study developed a real-time quantitative PCR (qPCR) method for NNV monitoring. The assay showed a strong linear correlation (r(2) = 0.99) between threshold cycle (C(T)) and RNA quantities, which allowed identification of infected groupers by the C(T) value and could be exploited to warn of NNV infection prior to an outbreak in grouper fish farms. Real-time qPCR also confirmed the copious content of NNV in grouper fin, similar to that in primary tissues; the result was verified by using in situ reverse transcription-PCR (RT-PCR). This indicated that grouper fin was a suitable sample for NNV detection, in a manner that could be relatively benign to the fish. The rapid spread of NNV infection to the entire population of affected farms was evident. The developed real-time qPCR method is rapid, highly sensitive, and applicable to routine high-throughput detection of large numbers of samples and has potential as a suitable tool for diagnostic, epidemiological, and genetic studies of grouper aquaculture.

Geographic information system applied to measuring benthic environmental impact with chemical measures on mariculture at Penghu Islet in Taiwan

Cobia, Rachycentron canadum, is currently grown by marine aquaculture in Taiwan, particularly on Penghu Islet. Although the effect of marine aquaculture on the environment has been the subject of many studies, an understanding of its environmental impact has yet to be attained, and the continuing expansion of cage farming has caused noticeable ecological declines. Nevertheless, useful tools to measure this environmental degradation are scant. The results of this study suggest that the combination of a geographic information system (GIS) with redox potential and sulfide measurements can be used to definitively assess the condition of the benthic environment near cobia aquaculture sites and to help develop environmental monitoring programs. These applications could easily be adopted to assess multiple marine environmental conditions.

Technical assessment of the use of a small-scale wind power system to meet the demand for electricity in a land aquafarm in Taiwan

Due to the widespread aquaculture at coastal area in Taiwan and high wind power potential in the sites, it is worthy to carry out the technical potential assessments of small-scale wind power system used for aquaculture in Taiwan. The present work analyzed wind power potential, described the practical installation, measured the actual energy output, verified the reliability of the energy output estimation method and elucidated important considerations associated with the use of this estimation method. The relationship between the actual energy generated and the wind speed characteristics were thus introduced. The power quality produced by a small-scale wind power generator was also evaluated.

The competitiveness of the eel aquaculture in Taiwan, Japan, and China

The competitiveness of eel aquaculture in Taiwan, Japan, and China was investigated using the net private profitability (NPP) and the domestic resource cost (DRC) approaches. Estimated results show that Japan is the least competitive. The competitiveness between Taiwan and China has changed in the last decade. Between 1990 and 1993, the Taiwanese DRCs were lower than those of the Chinese, implying that Taiwan led in competitiveness. After 1994, however, the Taiwanese eel aquaculture lost its position to China. According to the analyses mentioned above, it does not matter which approach is adopted in assessing competitiveness. Our findings suggest that the Chinese eel aquaculture possesses competitive advantage over Taiwan and Japan.

Aquaculture and the endogenous damage cost of water pollution: The case of Taiwan

The endogenous damage cost of water pollution to eel production is derived based on a certainty equivalent model that takes into account a farmer's avoidance behaviour against water pollution, and differentiates the productivity effect of pollution control inputs from conventional productive inputs. Whether the marginal damage cost increases with pollution concentration depends on the difference between the direct damaging effect and the induced damage‐reducing effect. A decreasing marginal damage cost curve of eel aquaculture in Taiwan is elicited, which explains partly the failure of a Coasian approach experimented in a recent conflict due to water pollution.

Feasibility Study for Alternative Culture Species in Taiwan—Penaeus penicillatus

Abstract Penueus monodon has become almost synonymous with aquaculture in Taiwan, indicating the level of commercial success it has attained over the past two decades. However, other species are being considered for future culture to diversify an industry overly dependent on one product, as well as to provide the market with an alternative commodity. This paper explores the feasibility of P. penicillatus as an alternative culture species in Taiwan. P. penicillatus has seven merits that make it ideal for aquaculture: 1) P. penicillatus is comparatively resistant to low temperature. 2) It is a medium sized “white prawn” and is attractive to the consumer. 3) The migration behavior shows good possibilities for culture in sea water. 4) Wild spawners are abundant and natural, and induced spawning in captivity is relatively easy. 5) Larvae spontaneously spawned in captivity show good survival, existing on the natural food present in the pond. 6) It has a low protein requirement and has good growth in the early stages even at high stocking densities of 100–120 prawns/m2. 7) P. penicillutus grows to a comparatively uniform size. This paper also discusses some difficulties in the culture of this prawn.

INTRODUCTION TO AQUACULTURE IN TAIWAN1

ABSTRACTTaiwan is located in the subtropical region with the Tropic of Cancer crossing at mid‐island. The warm weather permits a growing season of 8–10 months for most warm water species. It is generally believed that aquaculture has been practiced in Taiwan for some 300 years. In 1977, the total pond area under aquaculture in Taiwan was 31,757 ha, including 13,460 ha of fresh water and 18,297 ha of brackish water. The area of reservoir and paddy field utilized for culture was 8,550 ha. In addition, there were 14,646 ha of shallow sea along the west coast of Taiwan and coastlines of Penghu (Pescadores) utilized for seaweed, oyster and clam culture. Total aquaculture production in 1977 was 139,628 metric tons, accounting for 16.3% of the year' total fishery production; of this, 61,285 metric tons were from freshwater ponds, 38,466 metric tons from brackish water ponds, 8,838 metric tons from reservoirs and paddy fields, and 31,039 metric tons from shallow sea culture.The organisms under aquaculture include finfish, crustaceans, molluscs and seaweeds. However, limitations arising from scarcity of land available for conversion into aquafarms and water pollution problems have partially restricted expansion.All aquaculture production in Taiwan has been achieved in the private sector largely by individual farmers and a small number of companies mostly involved in eel and shrimp culture enterprises. Research and extension services have been supported by the government. Emphases of aquaculture research have been on controlled reproduction, intensive culture systems and fish diseases. Technical advances have been made in the artificial propagation of major Chinese carp, grey mullet, penaeid shrimp, Macrobrachium, small abalone, etc., development of cage culture of fish, intensive culture of eel and shrimp, hanging method of oyster culture and production of tilapia. Among the top priority problems are unstable seed supply of some important species, i.e., milkfish and eel, and high level technology to increase aquaculture operation per unit area.