Preliminary Assessment of Biofouling on Offshore Mussel Farms

Biofouling is a significant operational problem for the aquaculture industry globally; however, options for on‐farm management are limited. In New Zealand, the green‐lipped mussel, Perna canaliculus, has historically been cultivated at inshore locations, but increased competition for space has led the industry to develop offshore farming sites several kilometers from the coast. We hypothesize that the distance to these farm sites from coastal locations, and their placement over extensive soft‐sediment habitats, may provide a barrier to colonization by biofouling species with limited natural dispersal abilities. A study of two offshore mussel farms revealed that they supported relatively impoverished biofouling communities by comparison with inshore mussel farms and other artificial structures. Offshore sites had a relatively low number of taxa and a low prevalence of short‐dispersing organisms such as ascidians, which are a problematic group of fouling organisms in aquaculture. We suggest that newly established offshore marine farms have the potential to be kept free of a range of problematic fouling organisms, provided the introduction of such species via human transport pathways can be mitigated.     

Preferences for and perception of cultured marine baitfish by recreational saltwater anglers in Florida

There is strong interest in culturing live marine baitfish for anglers. However, there is scant information about saltwater anglers’ perception of cultured baitfish. Thus, a survey was developed and administered to assess recreational saltwater angler’s preferences for baitfish, their attitudes towards cultured baitfish, supply and demand, and specific information about pinfish (Lagodon rhomboides) and pigfish (Orthopristis chrysoptera). An online survey invitation was e-mailed to 227,829 licensed marine recreational anglers in Florida. A total of 14,871 respondents completed some portion of the survey (6.5% response rate). Inshore destinations were the most common fishing trips taken. Live bait was caught by 57.8% of respondents, purchased by 32.1%, and 10.1% did not use live bait. Perceptions of aquaculture as a means of producing bait were 43.8% positive, 20.6% somewhat positive, and 31% unknown. Consistent availability and price were identified by anglers as the two most important characteristics for an aquaculture produced marine baitfish.     

The use of information technology in aquaculture management

Abstract

The recent advances in information technology (IT) have had profound impacts on all walks of life and aquaculture is no exception. The growing importance of aquaculture as an alternative source of protein has further emphasized the need to adapt and develop advanced IT for the better management of aquaculture facilities as well as the regional planning for aquaculture development.

It is the objective of this paper to review the use and potential prospects of IT in aquaculture management. The information technologies considered are instrumentation and process control, data management, computerized models, decision support systems, artificial intelligence and expert systems, image processing and pattern recognition, geographical information systems, and information centres and networks. The review includes a brief introduction of each of the aforementioned technologies, followed by a survey of their current application as well as their potential use in aquaculture management.     

我国离岸养殖工程发展策略

发展离岸养殖工程对于保障水产品供给、开发蓝色国土资源、实现海洋水域资源的合理利用与有效开发具有重大意义。本文阐述了我国网箱养殖工程发展现状和面临的主要问题,介绍了国外在深水抗风浪网箱和养殖工船方面的研发进展,指出未来离岸养殖工程发展趋势是养殖设施系统大型化、养殖环境生态化、养殖地域外向化、养殖过程低碳化,提出了我国离岸养殖工程发展战略目标是:至2020年,全面形成面向深海、合理分布于主权海域的海上水产品养殖生产与流通体系,实现海洋渔业由"捕"向"养"的根本性转变,建立领先于世界的工业化蓝色农业生产体系。     

Developing a marine protected area network with multiple objectives in China

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An overview of aquaculture in Turkey: With emphasis on sea bass and sea bream

Abstract

Aquaculture is a relatively recent industry in Turkey, enjoying great potential for development. Both freshwater and marine aquaculture are being practised in over 800 operational units. Rainbow trout (Oncorhynchus mykiss), Sea bream (Sparus aurata), Sea bass (Dicen‐trarchus labrax), comprise 90% of the total production, together with Atlantic salmon (Salmo salar), Common carp (Cyprinus carpio), Shrimp (Penaeidae spp.) and Mussel (Mytilus gal‐loprovincialis). Total aquaculture production reached 45 450 t in 1998, constituting 9% of total national fisheries production. Sea bass and sea bream farms are located along Aegean Sea and Mediterranean coasts and comprised 16% of the total number of aquaculture enterprises and 30% of total aquaculture production in 1997. Supplies of these two species have been steadily increasing in Turkey and other producing countries since 1990 resulting in market saturation and declining prices both locally and internationally. Mediterranean species including Epinephelus spp., Puntazzo puntazzo and Pagrus pagrus, are considered to be new candidates offering good prospects for mariculture.     

Broodstock spawning and larviculture of whiting (Merlangius merlangus L.) reared in captivity

In recent years, an increasing interest in the farming of marine ‘white’ fish, such as cod, has been observed in the aquaculture industry. One species being considered for aquaculture development is whiting (Merlangius merlangus L.). With little data being available on the domestication of this species, our study aimed to characterize spawning behaviour and rhythmicity in captive broodstock and provide original data on egg incubation, embryonic development and larval rearing. The results observed through video recording showed that spawning mainly occurred at night with active courtship behaviour. Daily egg batches were collected from two separate spawning seasons, with an average fertilization success declining from 77% to 53%. Time to hatch was inversely related to the incubation temperature and occurred after 78 degree‐days (9 days at 8 °C), with emerging larvae ranging in size from 3.3 to 3.46 mm total length and hatch success ranging from 48.3% to 99.9%. In comparison with a clear water environment, a green water regime during the first days of larval rearing significantly improved larval growth and survival. These results are the first to describe spawning activity, early development and larval performances in whiting and are promising for the potential future development of whiting aquaculture.     

The nutrient footprint of a submerged‐cage offshore aquaculture facility located in the tropical Caribbean

The effect of effluent generated by a commercially scaled offshore (~13 km) finfish aquaculture facility in the tropical Caribbean on the water column and benthic nutrients and chlorophyll‐a is described. Water column samples were collected up‐ and downstream of the site at various times between 2012 and 2018. Typically, no significant difference in dissolved oxygen, chlorophyll‐a, particulate organic carbon, particulate organic nitrogen, nitrate + nitrite, and total dissolved nitrogen concentration was observed in the water column between the up‐ versus downstream samples. Similarly, sediment samples were collected at various times between 2012 and 2018. Samples were collected at up‐ versus downstream locations and analyzed for benthic carbon, nitrogen, and chlorophyll‐a content. Some of the collected data demonstrates a trend toward sediment enrichment within the vicinity of the farm. These data are of interest to stakeholders concerned with the expansion of offshore aquaculture in the United States and other countries. To our knowledge, this is the first report of its kind from a commercially scaled aquaculture facility utilizing offshore submersible‐cage technologies.     

Technical efficiency of carp production in Nepal: An application of stochastic frontier production function approach*

Abstract

Modern aquaculture is a relatively new activity among Nepalese farmers and a small contributor to the economy. Given the abundance of water resources and fish species, rising demand for fish, and its high profitability, aquaculture has potential for future expansion if it is given appropriate attention from the government. In Nepal, productivity in aquaculture is much lower compared to other countries in the region, which suggests that there is potential for increased fish production through technological progress and improvement in farm‐level technical efficiency. However, no formal analysis has yet been conducted to assess the productive performance of Nepalese aquaculture and its potential for future improvement. Against this background, this paper examines the technical efficiency and its determinants for a sample of fish pond farms from the Tarai region of the country using a stochastic production frontier involving a model for technical inefficiency effects. The estimated mean technical efficiency is 77%, with intensive farms being more efficient than extensive farms. The adoption of regular fish, water, and feed management activities has a strong positive effect on technical efficiency.     

A long‐term approach to aquaculture development: Bahrain

Abstract

Bahrain, located in the Arabian Gulf, is composed of low‐lying islands made up primarily of sand covering limestone bedrock. The climate is extreme with seawater temperatures ranging between 8 and 38 °C. Seawater salinity ranges from about 40–60 p.p.t. Freshwater resources are limited with about half the freshwater consumed coming from desalinization plants. Total fish landings have increased over time with some fluctuations. Per caput consumption has dropped from a high of 27.2 kg/caput (1985) to 12.6 kg/caput (1997). Landings for certain preferred species have declined dramatically over the last 10 years. For example, total grouper landings have declined about 70% in 10 years. This has resulted in increased prices at the local market. Bahrain has no history or tradition of aquaculture. In 19 79, FAO conducted an initial assessment of aquaculture in Bahrain. This led to construction of basic laboratory facilities and some baseline aquaculture experiments. A second phase was started in the early 1990s that included establishing the National Mariculture Center (NaMaC). Initial work at NaMaC concentrated on small‐scale culture trials of orange‐spotted grouper, Epinephelus coioides, pearl‐spotted rabbitfish, Siganus canaliculatus and yellow‐finned black seabream, Acanthopagrus latus. Recently, NaMaC has been successful in mass culture of the sobaity bream, Sparidentex hasta. The initial 1979 FAO study recommended an economic assessment of aquaculture in Bahrain. An initial financial assessment was finally completed in 1994. At that time, hatchery and grow‐out production was not financially feasible. A subsequent grouper grow‐out production study indicated that if seed supplies could be assured, grow‐out operations might be financially feasible. Additional economic studies have been completed on feed and cage suppliers. In addition, local market surveys indicated good consumer acceptance of aquaculture products. Aquaculture management in Bahrain is under the Directorate of Fisheries. The goal of mariculture development in Bahrain is the establishment of a commercially viable private sector industry. This has yet to be achieved. Regulations for such an industry have been drafted, but have not yet been formalized. Bahrain has taken a long‐term perspective to aquaculture development. It has set up infrastructure and is developing technology to support commercial aquaculture. However, financial constraints have limited, but not stopped progress towards development of a commercially viable industry. As the economic conditions and the fisheries change, feasibility of such an industry should continue to improve.     

Effect of support medium,hydraulic loading rate and plant density on water quality and growth of halophytes in marine aquaponic systems

The development of marine intensive land‐based aquaculture systems has been limited due to the absence of methods to manage saline wastewater. Aquaponic systems, although commonly applied to freshwater aquaculture, can potentially manage nutrient wastes while providing a secondary product. The aim of this study was to evaluate both the capacity for water treatment and the production requirements of two saltwater‐tolerant plant species (Sesuvium portulacastrum and Batis maritima) when grown hydroponically in a marine aquaponic system. The presence of plants was found to significantly contribute to nitrate removal, such that mean nitrate concentrations were 10.1 ± 5.4 and 12.1 ± 6.1 mg/L NO₃^?‐N in planted and unplanted treatments respectively. The use of coconut fibre as a planting medium also significantly contributed to nitrate removal, such that mean nitrate concentrations were 9.78 ± 5.4 and 12.4 ± 6.0 mg/L NO₃^?‐N in coconut fibre and expanded clay treatments respectively. Daily nitrogen removal was greatest in the coconut fibre/plants treatment, ranging from ?18% to 67%. Hydraulic loading rate, plant species and plant density did not significantly affect water quality or plant growth. The low flow/saltwort/low density treatment had the greatest mean daily nitrogen removal, ranging from 25% to 172%. The results indicate that the main nitrogen removal mechanisms were simultaneous nitrification–denitrification in the hydroponic plant beds and nitrogen removal through plant growth. This study demonstrates that marine aquaponics could be an effective way to manage nutrient removal in marine land‐based aquaculture systems.     

海水网箱网衣防污技术的研究进展

海水网箱养殖中,网衣污损附着物会影响网箱设施安全及其养殖鱼类的健康生长,因此,网衣防污是网箱养殖业备受关注的问题.本文在简述海水网箱网衣分类与特点的基础上,重点介绍了人工清除法、防污涂料法、机械清除法、金属合金网衣防污法、箱体转动防污法、生物防污法、网衣本征防污法等网衣防污技术最新研究进展;结合本课题组在网衣防污方面的...     

Combined effects of a simulated marine heatwave and an algal toxin on a tropical marine aquaculture fish cobia (Rachycentron canadum)

Ongoing global warming is one of the major challenges for the development of aquaculture in the tropical regions where species are already cultured in the water temperature close to their upper physiological thresholds. Furthermore, warming can trigger blooms of toxic algae, yet we do not know how extreme warming such as a marine heatwave (MHW) and algal toxins may affect marine aquaculture species. To address this issue, we investigated the effects of a simulated MHW in combination with exposure to trans‐4‐trans‐decadienal (PUA), a diatom‐derived toxin, on survival, growth, development and biochemical composition of cobia larvae and juveniles. Cobia larvae were exposed for 48 hr to one of two temperatures (29 vs. 34°C) and two PUA treatments (0 vs. 0.5 µM). Surviving larvae from each treatment were divided into two subsets: three replicates were used for the feeding test and five replicates were used for the recovery test in a non‐contaminated environment at the respective temperatures of 29 or 34°C. Survival of cobia larvae was reduced by 16% in either MHW or PUA, but it dropped by 60% when both stressors were present, indicating a synergistic effect. MHW, but not PUA, reduced the feeding of cobia larvae. PUA had no delayed effects on growth rate and biochemical composition of the fish. MHW strongly reduced specific growth rate, body protein and lipid contents in cobia. Our results provide the first empirical evidence of how MHW and toxic algae may interact and challenge cobia and marine aquaculture production in tropical countries.     

Economics of cage culture in Puerto Rico

Abstract

Puerto Rico has been faced with a decline of fish stocks similar to other parts of the world. Offshore cage aquaculture might be an answer to this problem although there are many unanswered questions. This paper describes a project in Puerto Rico that assessed the economics of offshore cage culture for aquaculture. The first cage was placed in the water in February 2002 with a second one to follow shortly thereafter.     

Far‐reaching effects of a seal scarer on harbour porpoises,Phocoena phocoena

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中国海带养殖向离岸深水区发展的初步探讨

海带(Saccharina japonica)是我国重要的经济海藻之一,我国海带养殖业已形成了完整的技术链条和产业链条。近年来,在内外因素双重驱动下,我国海带养殖业呈现出向离岸深水区发展的趋势。本文围绕海带离岸养殖,介绍海带近岸养殖和离岸养殖的概念,对比分析海带近岸养殖和离岸养殖的优劣势,探讨海带离岸养殖发展的动因,总结海带离岸养殖发展的现状与问题,为海带离岸养殖发展提出建议和对策,以期为海带养殖产业的健康、可持续发展提供新思路、新理念。     

Attitudes towards marine mammal conservation issues before the introduction of whale‐watching: a case study in Aruba (southern Caribbean)

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Implications of marine environment change on Japanese scallop (Mizuhopecten yessoensis) aquaculture suitability: a comparative study in Funka and Mutsu Bays,Japan

The determination of the causes for the changes in marine environment in areas with similar oceanic climate forcing on most suitable sites for scallop aquaculture can help to ensure long‐term sustainability of the coastal ecosystem. This study assessed aquaculture suitability sites using dominant indicators of marine ecological dynamics on Japanese scallop culture in Funka and Mutsu Bays, Japan as comparative examples. Data sources comprised of Moderate Resolution Imaging Spectroradiometer (MODIS), four dimensional‐variational (4D‐VAR) data assimilation system, Advanced Land Observing Satellite (ALOS), in situ and buoy measurements. The suitable sites were ranked on a scale of 1 (least suitable) to 8 (most suitable). In the most suitable sites in aquaculture operational areas, Funka Bay had a high proportion (51.1%) than Mutsu Bay (13.7%) for the best performed model. Peaks of aquaculture suitability scores were attributed to potential effects of currents. Extreme sea temperatures (>24°C) in summer 2010 were associated with low performance of the 2010 model in Mutsu Bay and mortality of scallops based on sea temperature‐depth visualizations. Future global warming effects are likely to decrease the most suitable culture sites in Funka Bay and loss of similar areas in Mutsu Bay. Thus, change in marine environment influences scallop culture development. Such concepts could form scientific basis for aquaculture planning on designated system of larval distribution and stock management of cultured species to minimize mortality and economic losses.     

Aquaculture in Egypt and issues for sustainable development

Abstract

Although aquaculture in Egypt has the potential for satisfying the increased demand for protein and has been experiencing unprecedented growth during the last decade, questions remain regarding the sustainable development of the industry. It is thus the objective of this article to review the current status and practices of the aquaculture industry in Egypt, highlighting the major issues confronting the sustainable development of the aquaculture industry.

Several issues are identified as limitations to future sustainable development, namely, production technology, fry supply, a feed industry sufficient to meet the demands of a growing aquaculture industry, and marketing and distribution systems necessary to accommodate the strong seasonal supply pattern. The article then concludes with a discussion of recommendations for alleviating these limitations.     

The importance of live‐feed traps – farming marine fish species

This article analyses the challenges of different live‐feed regimes for the rearing of marine finfish larvae and discusses the potential alternative live feeds to avert a future live‐feed trap. Live feeds are indispensable for the successful rearing of larvae of most marine fish species. Brine shrimps (Artemia) and rotifers comprise the live feeds of choice in marine aquaculture today. However, their nutritional composition is deficient in especially essential fatty acids, and enrichment with fish oil is needed. Fish oil is considered a limited resource owing to its origin in fully exploited wild fish stocks. Moreover, fluctuations of the natural population of Artemia will, most likely, influence future availability and prices. This emphasizes the need for optimal exploitation of available live‐feed resources and development of new sustainable alternatives, such as copepods. An array of solutions to these problems are presented to avoid a future live‐feed trap and to reduce dependence on limited resources that influence future production possibilities, species diversification, price volatility and productivity in the aquaculture sector.