An evaluation of the role and impacts of alien finfish in Asian inland aquaculture

Asia dominates global aquaculture production accounting for over 80% of the total and the mainstay in Asian aquaculture is finfish. Over the years, Asia has experienced a number of inter‐continental and intra‐continental transfers/introductions/translocation of finfish species, between nations and watersheds, beyond their natural range of distribution, primarily for aquaculture development. In this article all such species are referred to as alien species. An attempt is made to evaluate the importance of the production of alien species in selected Asian nations, using statistics of the Food and Agriculture Organization. Also, negative effects, if any, based on literature surveys, of alien species in relation to displacement of indigenous species, and on biodiversity and/or genetic diversity together with associated pathogen transfers are evaluated. The major alien species, based on their significance to Asian inland aquaculture considered, are the tilapias, catfish, Chinese and Indian major carps and common carp. It is estimated that currently alien species account for nearly 12% of the cultured finfish production (2.6 million tonnes) in Asia, valued at US$ 2.59 billion, and the contribution exceeds 40% when Asian countries excluding China are taken into consideration. Inland finfish aquaculture in some Asian nations, such as Indonesia and the Philippines, is predominated by alien species, and in some others, e.g. Bangladesh and India, the contribution from alien species has been increasing steadily. It is suggested that overall alien finfish species have done little ecological harm to native flora and fauna. However, in the wake of increasing anthropogenic development taking place in watersheds the resulting environments are often made unconducive to indigenous species but not to some alien species, thereby potentially and indirectly making the latter invasive.     

Understanding the economic and farming practices driving species selection in aquaculture within the Mymensingh division of Bangladesh

Aquaculture is a major supplier of animal protein for Bangladesh’s population, and the Mymensingh division is a major contributor to finfish aquaculture, producing 43% of the total pond pangasius and 9% of the total amount of tilapia (figures from 2018). We conducted a finfish farmer survey covering Netrokona, Jamalpur and Mymensingh districts to understand current finfish farming practices and identify factors that drive farmers in their species choice between pangasius or tilapia cultivation. We found that most finfish farmers in Mymensingh are experienced practitioners and practise polyculture with a range of stocking densities for each species. Using an economic model of polyculture practice, we have shown that over a production cycle, pangasius gain body mass at a rate nearly 4 times greater than that for tilapia, resulting in substantially larger revenues and providing a strong incentive for their culture. High levels of tilapia aquaculture likely persist due to their short production cycle and an associated decreased economic risk due to crop loss from disease, both factors providing a strong incentive for their culture. Our findings also indicate production yield differences through different species selection in polyculture systems. For example, co-culturing pangasius, tilapia and carp together was less productive than co-culture of pangasius with tilapia. Furthermore, higher yields of tilapia were obtained when co-cultured with carp compared with pangasius, the reasons for which are not known and warrant further investigation. Our study uses information provided by finfish farmers to produce a useful guide on fish species choices to maximise production yields, and therefore food production, from their ponds.

     

Review of climate change impacts on marine aquaculture in the UK and Ireland

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Macro-economic factors influencing world aquaculture production

Abstract. The influence of macro-economic factors on production and consumption of aquatic products in the world was evaluated. World aquaculture production and its growth were analysed in terms of commodities, species, countries and regions. Special attention was given to interpreting the consequences of the results obtained on policy and planning of future aquaculture development.
The consumption of both aquafood and meat increased significantly with income on a per caput basis in the world. The ratio aquafood:meat decreased with increasing per caput income, stressing the relative importance of aquafood in low-income countries. A significant correlation between the consumption of aquafood and aquaculture production was found for Asia, Europe and on a world-wide scale and it is therefore argued that fisheries pave the way for aquaculture development. Growth of finfish culture tends to correlate with agricultural growth. Africa and Latin America have low aquaculture productions compared with their aquafood consumption. These regions offer the highest probability for rapid growth in aquaculture production in the near future.     

Growth and condition index of mussel Mytilus galloprovincialis in experimental integrated aquaculture

Integrating mussel and finfish aquaculture has been recognized as a way to increase profits and decrease environmental impacts of finfish aquaculture, but not enough is known about the effects of finfish aquaculture on mussel growth. Here we present a pilot study aimed at determining how distance from finfish aquaculture affects mussel growth. To this end, we measured growth and condition index of mussel (Mytilus galloprovincialis) at three different distances (0, 60 and 700 m) from finfish aquaculture in the eastern Adriatic Sea. There was a statistically significant difference in growth of tagged mussels with respect to site. Average measured lengths of mussels at sites 1, 2 and 3 after the 10 months of the experiment were 57.60, 62.73 and 58.66 mm. Mussels grew fastest from March to May, and slowest from July to September, regardless of their position. Condition index showed spatial and temporal variations with higher values during fall and winter (∼23), and lower values during spring and summer (∼20). Our results show that production cycle in areas traditionally considered suboptimal for aquaculture can be equivalent to the cycle in areas traditionally considered optimal for mussel aquaculture if mussel aquaculture is integrated with finfish aquaculture.     

Bio-economical and ethical impacts of alien finfish culture in European inland waters

Since 1989, and in comparison to the global trend, inland aquaculture production of European finfish has declined. To date, the yearly European freshwater aquaculture production is 371,727 tons, valued at over US$1 billion. Indigenous species accounted for less than one-third of the production, whereas alien species (a species that has been moved beyond its natural range of distribution) accounts for the remainder. However, in general, indigenous species command a higher market price. Currently, food quality and food safety are leading concerns of consumers, and European consumers are also becoming alert to environmentally detrimental practices. Therefore, to aim at economic sustainability, the sector needs to satisfy consumer expectations of environmentally friendly practices. It is believed that farming alien finfish species can threaten local biodiversity through escapes, and this represents a current environmental concern relative to aquaculture. In this context, an attempt is made in this paper to understand and quantify the impacts of alien finfish cultivation in European inland waters, and to suggest remedial measures.     

An improved prioritization framework for selecting new finfish mariculture candidates for research and development in Indonesia

Aquaculture, particularly marine‐based production, is one of the fastest growing industries in Indonesia. Indonesia's competitiveness in the trade of aquaculture products is constrained by a lack of research and development (R&D) of new aquaculture species candidates. Mariculture has the greatest potential due to Indonesia's vast marine resources and archipelagic geography. Although there are over 3,000 species of marine fish in Indonesia, only 14 species have been widely cultured, largely finfish. Production is dominated by shrimp, groupers and milkfish. Traditionally, candidate species for mariculture in Indonesia and elsewhere have often been selected on their market value before their biological suitability for culture has been established leading to partially successful R&D efforts or even failure. The present study developed a framework for selecting marine fish species to support mariculture R&D in Indonesia based on an improved analytic hierarchy process (AHP). The approach combined various quantitative and qualitative data and involved different R&D stakeholder groups in the selection process. Ten species that had not been previously researched for their aquaculture potential were identified. The modified approach addressed the interaction complexity of criteria and different preferences across the stakeholders. The involvement of different stakeholders in the selection process not only ensured acceptance of the selected species for further research, but also tested the validity and consistency of the method used in this study. The methodology has relevance for mariculture globally given that efficient candidate selection can help focus efforts and investment in mariculture R&D.     

我国鲆鲽类生殖内分泌研究进展

鱼类的生殖和苗种繁育是鱼类养殖业持续健康发展的必要前提和关键技术基础之一,是海洋生物技术的重要研究领域.近年来,我国北方沿海鱼类繁殖生理主要围绕鲆鲽类“下丘脑-垂体-性腺轴”的组织结构特征、性腺发育规律、性类固醇激素、生殖相关功能基因内分泌调控机制等方面开展了较系统的研究.本文重点介绍主要养殖鲆鲽类“下丘脑-垂体-性腺轴”中表达的重要功能基因的研究进展,并综述了鲆鲽类生殖相关组织的结构及其内分泌系统特征、性腺发育的生理特性及其与环境因子和激素诱导的关系、性类固醇激素的表达变化规律及其与水温及光周期调控关系等.旨在为鲆鲽类生殖活动的精准调控和建立苗种繁育新技术提供参考.     

Application of Marine Foodfish Techniques in Marine Ornamental Aquaculture: Reproduction and Larval First Feeding

The long-term sustainability of the marine ornamental industry is being threatened by environmental pressures that are severely degrading the health of coral reef ecosystems. There is now a compelling need to practice resource conservation through the development of 'reef friendly' aquaculture technologies as an alternative to wild collection practices and to restore degraded wild populations. The commercial culture of marine ornamental finfish is very much in its infancy, but advances can be made more rapidly using insights from years of research and development with marine foodfish species. Many of the bottlenecks and constraints to developing marine ornamental fish culture are those now being addressed with the more challenging species of foodfish being attempted. The two key bottlenecks that currently limit expansion of the marine ornamental industry are the control of captive maturation and spawning and the identification of appropriate first-feed items for marine ornamental fish larvae. This paper highlights basic principles and recent achievements in marine foodfish culture that might be applicable to rapid development of controlled reproduction and propagation techniques for marine ornamental finfish.     

Evolution Through Innovation in Aquaculture: A Critical Review of the Greek Mariculture Industry

Marine aquaculture in Greece is a relatively new industry based on the culture of aquatic species such as the Mediterranean sea bass (Dicentrarchus labrax), gilthead sea bream (Sparus aurata), and Mediterranean mussel (Mytilus galloprovincialis). In the early 1980s, the results of research and development were applied to develop pilot semiacademic commercial farms. Such farms were gradually moved to the industrial scale of today, producing some 80,00–120,000 tons of finfish and up to 25,000–35,000 tons of mussels annually. The problems encountered during the adaptation of innovation to the production and management of this blue revolution is critically discussed from the early developmental phases up to the present.     

Recent Advances in Lumpfish Cyclopterus lumpus and Ocean Pout Macrozoarces americanus Larviculture

The aquaculture of marine finfish in Newfoundland presents a challenge due to the cold-water (<0 C) conditions which occur over a four to five month period. As part of a continuing research program on the culturing of cold-water marine finfish species we report on preliminary results of two "new" aquaculture species. The lumpfish and the Ocean pout both occur along the coast of Newfoundland and are adapted to a cold-water environment. Lumpfish have been reared from egg masses collected from the wild or from eggs stripped in the hatchery. Eggs and larvae are relatively large and larvae are well developed at hatch. Larvae will feed on day-old Artemia nauplii after four to six days. Survival over the first eight weeks is high but declines over the first year. Lumpfish cultured in the laboratory become sexually mature and produce eggs (roe) at the end of their second year. Ocean pout have been cultured only from egg masses collected from the wild. Eggs and larvae are extremely large compared to other marine finfish currently being cultured. Larvae hatch during the cold-water period, absorb the yolk-sac within 24 hours and are ossified at hatch. Juveniles feed on Artemia nauplii within two days at very low temperatures. Survival is comparatively high (75–80%) over the first year. Initial results are encouraging but more research is required before commercial production of these species would be feasible.     

Characterization of supply of marine finfish species with potential for commercial growth in the United States

Global production of marine finfish has grown in total volume of production and the number of species farmed commercially, but there has been little production in the United States of marine finfish other than salmon and red drum. For most species considered to be ready for commercialization, there are few or no farms from which to evaluate the size of the market or to estimate revenues and costs necessary to assess economic feasibility. This present study takes a first step to fill this gap with an analysis of the existing supply of 20 marine finfish species identified as candidates for commercialization in the United States, as a proxy for effective demand (the volume of a product sold at the market equilibrium price). Secondary data from 1950 (where available) through 2019 were compiled on each species, including (1) global aquaculture production, (2) US aquaculture production, (3) US commercial landings, (4) US recreational landings, and (5) imports. Current effective market demand (measured as the sum of commercial landings, farmed production, and imports) was low, totaling 36.6 million kg across the 20 species, which is equivalent to less than 23% of the annual volume sold of US farmed catfish. Commercial landings for 17 of the 20 species exhibited declines, potentially offering opportunities for farmed product to capture market share by filling the increasing gaps in supply. The variability in commercial landings provides opportunities for farms to capitalize on their advantage in supplying product with a high degree of consistency of volume, size, delivery frequency, and quality. Several unknown factors suggest the need for follow-up studies on consumer preferences, degree of substitutability among finfish species, and effects of recreational landings on demand. An important limitation to prospective producers is the lack of species-specific import data for the generic categories of “flounder,” “bass,” and “snapper.” This supply analysis provides a foundational analysis for prospective producers, investors, and researchers interested in commercialization of these marine species.     

中国深远海养殖发展方式研究

在渔业转型发展进程中,发展深远海养殖是突破生态环境和自然资源约束性挑战,实现新时期中国海水养殖业可持续发展的战略方向。基于联合国粮食及农业组织(FAO)关于深远海养殖发展的定义,结合中国海水养殖业发展水平和海域条件,对中国深远海养殖概念进行了界定。提出养殖品种选择、养殖系统构建、养殖海域规划是关系深远海养殖产业稳步有序发展的重要因素。在养殖品种选择方面,应重点考虑经济潜力、适应水温和养殖技术;在养殖系统构建上,分析比较了不同养殖系统应用于深远海养殖的适宜性、安全性和经济性;在养殖海域规划方面,应重点考虑养殖排放、环境承载力和海域条件。     

A comprehensive survey on selective breeding programs and seed market in the European aquaculture fish industry

The use of selective breeding is still relatively limited in aquaculture species. Information on such activities is sparse, hindering an overall evaluation of their success. Here, we report on the results of an online survey of the major aquaculture breeding companies operating in Europe. Six main reared fish species were targeted. A total of 31 respondents contributed to the survey, representing 75 % of European breeding organizations. Family-based breeding schemes were predominant, but individual selection was more frequently applied in marine species. Artificial fertilization is the preferred means of reproduction; however, mass spawning is often used as a fallback method. The most frequently selected trait is growth performance, but the number of selected traits has been increasing over the years through the addition of traits such as disease resistance or product quality. The use of molecular tools is now common in all programs, mainly for pedigree traceability. An increasing number of programs use either genomic or marker-assisted selection. Results related to the seed production market confirmed that for Atlantic salmon there are a few dominant players at the European level, with 30–50 % market share. Only part of the European fish aquaculture industry today fully exploits selective breeding to the best advantage. A larger impact assessment still needs to be made by the remainder, particularly on the market share of fish seed (eggs, larvae or juveniles) and its consequences for hatchery stability.     

Exogenous enzymes as functional additives in finfish aquaculture

Exogenous enzymes, including protease, lipase, carbohydrate enzyme and phytase, are widely used as additives in fish feed worldwide. The chemical effects of these enzymes are well understood; however, their benefits to fish remain controversial. This review aimed to explore the current state of knowledge on the impacts of exogenous enzymes on finfish aquaculture, and demonstrate the application of exogenous enzymes as a safe and efficient bio‐additive to regulate growth performance, digestibility, feed utilization, whole‐body composition and immune performance of fish, and reduce phosphorus pollution into environment. Overall, based on the current knowledge and information gathered in this review, it is clear that the research on exogenous enzyme supplementation in finfish aquaculture is not extensive. It may be significant to increase research on this subject in future because it could broaden the application of exogenous enzyme use in diets where they cannot be applied currently.     

INTEGRATED MULTI − TROPHIC AQUACULTURE (IMTA): A POTENTIAL STRATEGIC CHOICE FOR FARMERS

Integrated multi-trophic aquaculture is one approach to mitigate ecological effects of finfish mariculture, and its benefits are prompting increased interest among researchers and commercial growers worldwide. A project in the Bay of Fundy in eastern Canada has demonstrated the biological and technical feasibility of integrated multi-trophic aquaculture, with uniformly positive results. This paper examines its economic and social implications. Capital-budgeting results suggest that using the waste of one crop as feed for another can increase profits. Scenario analysis also indicates that financial risks are reduced if weather-related or market risk for the various species are not correlated. Surveys indicate a positive perception towards integrated multi-trophic aquaculture by the public, which should assist integrated multi-trophic aquaculture applicants for site licences, and perhaps reduce litigation and lobbying by aquaculture opponents.     

Forecasting the Genetic Impacts of Net Pen Failures on Gulf of Mexico Cobia Populations Using Individual‐based Model Simulations

Offshore net pen fish farming provides a cost‐efficient means for production of marine finfish, and there is great interest in development of net pen operations in domestic waters. However, there are concerns over the possible genetic and ecological impacts that escaped fish may have on wild populations. We used individual‐based simulations, with parameter values informed by life history and genetic data, to investigate the short‐term (50 yr) impacts of net pen failures on the genetic composition of cobia, Rachycentron canadum, stocks in the Gulf of Mexico. Higher net pen failure rates resulted in greater genetic impacts on the wild population. Additionally, the use of more genetically differentiated source populations led to larger influxes of non‐native alleles and greater temporal genetic change in the population as a result of net pen failure. Our results highlight the importance of considering the appropriate source population for broodstock collection in net pen aquaculture systems and help to provide a general set of best management practices for broodstock selection and maintenance in net pen aquaculture operations. A thorough understanding of the genetic diversity, stock structure, and population demography of target species is important to determine the impact escapees can have on wild populations.     

Design and performance of recirculating aquaculture system for marine finfish broodstock development

Tropical and subtropical climatic conditions in India present an ideal and unique opportunity for being the leader in tropical marine finfish aquaculture. However, the problem persist due to non-availability of marine finfish seed for the culture. In response to this problem, broodstock development of different tropical marine finfishes for seed production was started. The present study was undertaken to design a recirculating aquaculture system (RAS) and studying their performance in managing the various water quality required for the marine finfish broodstock development and breeding. The design of RAS, developed in the present study, included a broodstock tank, egg collection chamber, electrical pump, rapid sand filter, venturi type protein skimmer and biological filter. Two RAS were designed, one was stocked with a demersal fish species, orange spotted grouper (Epinephelus coioides) and the other was stocked with a pelagic fish species, Indian pompano (Trachinotus mookalee) at the rate 1 and 0.5 kg/m³ with a sex ratio of 1:1 and 1:2 (female: male) respectively. Various physio-chemical parameters, viz, total ammonia nitrogen (TAN), nitrite, nitrate, pH, alkalinity, temperature, free carbon dioxide (CO₂) and dissolved oxygen (DO) of both tank water were analyzed to assess the performance of recirculating aquaculture system in maintaining the water quality. Gonadal development of the fishes was assessed and the spawning performance was recorded and finally, economic performance of the system was also evaluated. During the entire experimental period, mean monthly total ammonia nitrogen was less than 0.07 and 0.06 mg L⁻¹ and mean monthly nitrite was less than 0.02 and 0.01 mg L⁻¹ in orange spotted grouper and Indian pompano RAS tanks respectively. The pH (7.8–8.2), DO (>4 mg/L) and alkalinity (100–120 mg/L) were found to be in optimum range in both recirculating aquaculture systems. Carbon dioxide was found to be nil during the entire experimental period in both the systems. In fact these levels were comparable or less than that is reported as the permissible limits for broodstock development. Indian pompano and Orange spotted grouper matured and spawning was obtained with production of fertilized eggs round the year. Economic evaluation showed the price of 10,000 fertilized eggs of orange spotted grouper to be US $ 1.33. The design of RAS devised in the present study is efficient in controlling and maintaining optimum water quality for broodstock development of both demersal and pelagic finfishes. The fishes stocked in RAS attained final maturation and round the year spawning was obtained.     

Genetic improvement in the Australian aquaculture industry

Most aquaculture industries in Australia are at an early stage of development and would benefit from the introduction of genetic improvement programmes. Size at harvest is perceived by industry participants, managers and researchers as the trait that will most influence profitability. Although most current genetic improvement programmes in aquaculture use mass selection, inbreeding is widely regarded as an important problem, which could be overcome by the use of family data in selection decisions. The major research priority is the development of genetic markers to enable accurate pedigree determination. The major constraint upon the implementation of genetic improvement programmes by aquaculture industries is lack of available funds and resources. Industry ownership and national co‐ordination of research and development is seen as the best way of addressing this constraint.     

Factors Driving Aquaculture Technology Adoption

Technology adoption has played a key role in the global development and increase in agricultural productivity. However, the decision to adopt a new technology on farms is complex. While the factors that drive the adoption of new technologies have been well studied in agriculture, less attention has been paid to drivers of technology adoption in aquaculture. Aquacultural technologies have developed and advanced rapidly in recent decades, but not all technologies have been adopted readily by farmers. This review paper summarizes some of the critical factors that influence aquaculture technology adoption decisions such as: (1) method of information transfer, (2) characteristics of the technology, (3) farm characteristics, (4) economic factors, and (5) sociodemographic and institutional factors. Fish farmers have tended to adopt technologies that are perceived to be more advantageous than others in terms of productivity, cost efficiency, and ease of management. Price of aquaculture products and profit expectations from business ventures were key economic factors influencing adoption decisions. Given the wide array of species, production practices, and global nature of aquaculture, the intensity and the extent of adoption of technologies depend on the nature of the industry in which they are adopted and their economic, social, political, and regulatory environments.