The Potential for the Restoration of Marine Ornamental Fish Populations Through Hatchery Releases

Populations of tropical and subtropical marine fish are being depleted worldwide to supply increasing demands of the aquarium industry and fresh seafood market. Overfishing and destructive harvest techniques have left some marine fish populations virtually extirpated in a number of primarily underdeveloped countries. In situations where only small remnant populations and significantly degraded habitat remain, population recovery even under the complete absence of collection will be slow, with the high potential for population loss due to natural environmental and recruitment variability. Stock enhancement, supplementing natural recruitment with hatchery produced fry, has the potential to significantly increase the rate of population recovery while maintaining population vigor.Stock enhancement research on Pacific threadfin has demonstrated measurable positive impacts on recreational and commercial fisheries for this species in experimental scale releases; similar successes can be expected for enhancement efforts directed toward species of ornamental value. The major technological barrier to ornamental fish enhancement, the development of appropriate culture capabilities, is being addressed in research directed to the commercial production of fish for the aquarium trade.     

Structure and Management Issues of the Emerging Ornamental Fish Trade In Eritrea

Following independence from Ethiopia in 1993, Eritrea resumed exploiting Red Sea and Arabian fish species for the ornamental trade in 1995 as a means to earn foreign exchange from sparsely exploited marine resources. This paper describes the findings of research conducted in 1997, in collaboration with the Eritrean Ministry of Fisheries. The capture, transport and export of aquarium fish were reviewed and potential impacts and the status of management were investigated through liaison with stakeholders and researchers. From 1995 to 1997 two companies exported approximately 60,000 fish per year, mainly to the USA, worth US$65,000 (export value). Seventy-five species (from 22 families) were exported. Damselfishes made up two-thirds of total exports but more valuable families (angelfishes and butterflyfishes) were more economically significant. To earn revenue for Eritrea, a 20% export tax was imposed, although this was calculated from declarations by the operators. The emerging nature of the trade allowed detailed monitoring by the Ministry of Fisheries. However, management efforts were constrained by a lack of capacity for enforcement and baseline research. Several potential effects of the trade exist but other, land-based impacts may be more pressing concerns for Eritrea's reefs. Research priorities for management are discussed as well as the implications of mariculture of Eritrean species by other nations.     

Ornamental Reef Fish Aquaculture and Collection in Hawaii

Ornamental fishes endemic to Hawaii's reefs are a valued resource and a staple of the marine aquarium trade, worldwide. At present, the market for Hawaiian ornamental reef fish is supplied entirely by the export of wild-captured animals, but the long-term sustainability of this practice is debatable. The success of breeders of ornamental fishes elsewhere, and concerns about overexploitation of wild fishes have stimulated interest in the development of an industry based on the captive propagation and rearing of Hawaiian ornamental fishes. Initial attempts to spawn and rear the larvae of various marine ornamental fishes in Hawaii were carried out in the early 1970s. The results of these culture efforts, conducted primarily at the Oceanic Institute and the University of Hawaii's Hawaii Institute of Marine Biology on Oahu, have varied in success. For the most part, these results have appeared previously only in dissertations or in reports distributed locally. Technological improvements in marine aquarium husbandry and in the culture of edible marine fishes have both benefited practitioners of ornamental reef fish culture, and promise to do so in the future. Our objective in this paper is to review the progress that has been made in the captive cultivation of ornamental marine fishes and to provide an overview of the status of the marine aquarium industry in Hawaii.     

Changes in frigate tuna populations on the south coast of Sri Lanka: evidence of the shifting baseline syndrome from analysis of fisher observations

• 1. This study examines changes in frigate tuna populations in southern Sri Lanka, based on reports from fishers in three age classes. Significantly higher values for best day's catch and largest specimen ever caught were obtained by older fishers than younger ones. Values were also significantly higher during early years, providing clear evidence of a decrease in the resource over time (1951–2007).
• 2. Older fishers reported best catches further inshore and in shallower waters which, on becoming depleted, forced younger generations to fish in less exploited areas further offshore. Heavy harvesting is also evident from the significantly greater number of sites reported by older fishers as being depleted, compared with observations of younger fishers.
• 3. These findings contrast markedly with catch and catch per effort patterns from statistics for frigate tuna and bullet tuna (combined) in southern Sri Lanka (1994–2004). No stock decline is evident, and at least one report in the early 1990s advocated increasing exploitation rates by 40% to maximize yields.
• 4. Although not a primary research objective, fisher observations on frigate tuna populations were also analysed to help evaluate possible effects of the 2004 tsunami. Most fishers reported post‐tsunami decline, but mainly from a larger new generation of fishers, rather than extra boats provided by aid money or (direct or indirect) biophysical impacts from the tsunami.
• 5. Reliance on fishery statistics, especially for mixed species and over a limited period, can be risky and easily mask true stock status. Evidence of harvesting effects on frigate tuna in southern Sri Lanka is evident using questionnaire data over a longer time scale.
• 6. This study provides another compelling case of the ‘shifting baseline syndrome’, whereby fishers of different ages have altered perceptions/experiences of their environment. This may be its first reported occurrence in Sri Lanka. Traditional knowledge from this and similar surveys may provide national fishery management with valuable insights and help improve conservation prospects for frigate tuna and other marine resources. Copyright © 2009 John Wiley & Sons, Ltd.

     

Essential Fish Habitat and the Effective Design of Marine Reserves: Application for Marine Ornamental Fishes

Extensive and unregulated harvest of marine ornamental fishes can lead to localized depletion of target species and habitat degradation from inappropriate collecting techniques. One potential solution to these problems is the creation of marine reserves where fishing is prohibited. Marine reserves have been shown to increase fish abundance and protect ecosystems from habitat destruction associated with fishing. If protective areas are to be effective, they must include the diversity of habitats necessary to accommodate the wide range of fish species that are of interest to the marine ornamental fish trade.Fish assemblages with high diversity and abundance are often associated with habitats of high structural complexity. A relationship between fish size and reef complexity suggests the importance of shelter as a refuge for certain fishes in avoiding predation. Many species tend to aggregate to spawn in structurally complex habitats to reduce their risk of predation. Closing of spawning areas during aggregation periods has been shown to be a highly effective management strategy for these species. The limited home ranges and high degree of habitat specificity associated with many marine ornamental fishes should make marine reserves a highly effective strategy for managing these resources.     

Global Advances in Conservation and Management of Marine Ornamental Resources

Currently, as many as 30 million coral reef fish belonging to 1,000 species are collected annually to supply private and public aquaria around the world. In addition, over 100 species of invertebrate are used, involving hundreds of thousands or even millions of individuals. The majority of these specimens come from coral reefs and associated habitats, with about 45 countries supplying the ornamental market. Considering the many pressures currently faced by reefs it is vital that ornamental fisheries are investigated and monitored, and management strategies formulated to ensure they are sustainable. This requires research, monitoring, training, use of non-damaging collecting methods and adoption of conservation strategies for controlling catch, such as reserves, quotas and closed seasons. There are also a number of possibilities for enhancing the fishery, such as mariculture and construction of artificial reefs. This paper concentrates on some of the conservation measures that can be taken and discusses their application and effectiveness. Such measures include limiting collecting effort, establishment of species-based or overall quotas, restrictions on rare and/or endemic species, temporary closures and establishment of fisherybreak reserves.     

Preliminary study on broodstock rearing,induced breeding and grow‐out culture of the sea cucumber Holothuria scabra in Sri Lanka

Experiments were conducted to identify suitable methods for broodstock rearing, induced breeding and grow‐out culture of Holothuria scabra in Sri Lanka. Two hundred and seventy‐two brooders (500–600 g) collected from off Mannar were individually packed in oxygen‐filled polythene bags with and without sea water and transported to a sea cucumber hatchery at Kalpitiya. Lagoon pens, sand‐filled fibreglass tanks and bare tanks were used in triplicates to maintain brooders. Spawning was initiated using air dry, water jet and thermal‐stimulation methods. Hatchery produced juveniles with an average weight of 11 ± 5 g were reared (2 individuals m^?2) in lagoon pens, mud ponds and fibreglass tanks in triplicates. The significantly high evisceration rate was observed when brooders were transported without sea water (t‐test, P < 0.05). Brooders maintained in bare tanks showed a significant weight reduction than the brooders in sand‐filled tanks and lagoon pens (anova , P < 0.05, d.f. = 2). Thermal stimulation (ambient temperature ± 3–5°C) was found to be the most successful method of spawning initiation of H. scabra. The mean (±SD) percentage males and females participated for spawning per trial was 9.2 (±10) and 4.6 (±5.6) respectively. On an average, 1.16 millions of eggs (±1.03 SD, n = 5) were obtained per spawning trial. H. scabra juveniles reared in tanks showed significantly lower growth rate than the juveniles in pens and ponds (anova , P < 0.05). Lagoon pens and sand‐filled tanks are suitable to maintain brooders and lagoon pens can be successfully used for mass rearing of juveniles.     

Larviculture of Mediterranean Marine Fish Species: Current Status and Future Trends

The larviculture of Mediterranean marine fish species has focused on the production of Spurus auruta and Dicentrarchus labrar . European fry production of these species has increased from 12 million in 1987 to 28 million in 1989 and is expected to rise to nearly 40 million fry in 1990.
Within differing hatchery systems, larval survival has been improved through the use of commercially available w3-HUFA rich live food enrichment diets. This combined with the use of surface cleaning techniques has led to a standardization of larval rearing procedures enabling mass production of quality fry. Increased concern with larval hygiene has resulted in larger larval rearing batch production and regular sterilization periods in most European units.
Market pressure is stimulating established producers to diversify their species range and industrial quantities of Puntazzo puntuzzo , and Pagrus major are already being produced. Work has started on the larval culture of Dentex dentex, Pagrus pagrus and Seriola dumerilli .     

7种观赏性剑尾鱼品种间杂交子代的体色及鳍形研究

7种观赏性剑尾鱼的自交、杂交,对其子代的体色(包括眼睛色彩)及鳍形等性状进行统计分析。试验结果表明,黑眼为显性基因控制,红眼为隐性基因控制,体色与眼睛颜色有一定的连锁关系;推测剑尾鱼体色遗传由数量性状基因参与控制;尾鳍燕尾相对于正常尾为显性,而且雄性尾鳍的燕尾和长臀鳍具有连锁性;高背鳍由显性基因控制,正常背鳍由隐性基因控制,拥有正常背鳍的个体,其基因型是隐性纯合,拥有高背鳍的个体,其基因型为杂合,初步推断显性纯合为致死基因型。     

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.     

Health Status of Ornamental Freshwater Fishes Imported to South Africa: A Pilot Study

Keeping fish is a popular pastime in South Africa and the majority of ornamental fish are imported. A pilot study was initiated to examine the health status of ornamental freshwater fishes imported to South Africa. Four groups of thirty fish each were examined for the presence of external parasites, and processed for virus isolation and for bacterial and mycobacterial culture. The groups consisted of goldfish (Carassius auratus), koi (Cyprinus carpio), guppies (Poecilia reticulata) and cardinal tetras (Cheirodon axelrodi). Mycobacterium fortuitum was isolated from the goldfish and koi. No other significant bacteria were isolated and virus culture was negative for all groups. Skin scrapings and wet gill preparations were made to detect external parasites. Parasites were identified from fixed material. External parasites included Trichodina mutabilis, Ichthyophthirius multifiliis, ciliophorans of the genus Tetrahymena, and monogeneans belonging to the genera Dactylogyrus and Gyrodactylus. This is the first report of Trichodina mutabilis in South Africa. Diseases imported with ornamental fish pose a risk to both indigenous fish populations and the aquaculture industry. This revised version was published online in August 2006 with corrections to the Cover Date.     

Coral Farming: Past, Present and Future Trends

There Have Been Significant Technical Advances in Marine Aquarium Maintenance in The Last 20 Years. It is Now Possible to Maintain, Grow and Reproduce in Aquaria Many of the Coral Species Found on Coral Reefs. Due to the increased Demand For Live Corals and Other Reef Invertebrates, The Commercial Production of these Organisms for the Home Aquarium Market Has Become Feasible. This Paper Describes the Early Beginnings of Live Coral Propagation, Current Coral Propagation Facilities Located in Europe, North America, and the Pacific Basin Followed by a Discussion of an Example of the Possible Future for Coral Farming, Namely Propagation by Sexual Reproduction. Suggestions for Areas of Further Research in Captive Coral Propagation are Also Presented.     

Culture-based fisheries in non-perennial reservoirs in Sri Lanka: production and relative performance of stocked species

Abstract In Sri Lanka, there is a great potential for the development of culture-based fisheries because of the availability of around 12 000 non-perennial reservoirs in the dry zone (<187 cm annual rainfall) of the island. These reservoirs fill during the north-east monsoonal period in October to December and almost completely dry up during August to October. As these non-perennial reservoirs are highly productive, hatchery-reared fish fingerlings can be stocked to develop culture-based fisheries during the water retention period of 7–9 months. The present study was conducted in 32 non-perennial reservoirs in five administrative districts in Sri Lanka. These reservoirs were stocked with fingerlings of Indian (catla Catla catla Hamilton and rohu Labeo rohita Hamilton) and Chinese (bighead carp Aristichthys nobilis Richardson) major carps, common carp Cyprinus carpio L., genetically improved farmed tilapia (GIFT) strain of Nile tilapia, Oreochromis niloticus (L.) and post-larvae of giant freshwater prawn, Macrobrachium rosenbergii De Man, at three different species combinations and overall stocking densities (SD) ranging from 218 to 3902 fingerlings ha⁻¹, during the 2002–2003 culture cycle. Of the 32 reservoirs stocked, reliable data on harvest were obtained from 25 reservoirs. Fish yield ranged from 53 to 1801 kg ha⁻¹ and the yields of non-perennial reservoirs in southern region were significantly (P < 0.05) higher than those in the northern region. Naturally-recruited snakehead species contributed the catches in northern reservoirs. Fish yield was curvilinearly related to reservoir area (P < 0.05), and a negative second order relationship was evident between SD and yield (P < 0.05). Chlorophyll-a and fish yield exhibited a positive second order relationship (P < 0.01). Bighead carp yield impacted positively on the total yield (P < 0.05), whereas snakehead yield impact was negative. Bighead carp, common carp and rohu appear suitable for poly-culture in non-perennial reservoirs. GIFT strain O. niloticus had the lowest specific growth rate among stocked species and freshwater prawn had a low return.     

雅砻江支流安宁河鱼类群落组成及资源现状

为了解安宁河鱼类资源现状,于2013年3月至2014年12月对安宁河及其支流18个采样点进行了5次调查,共计采集鱼类3 113尾,隶属4目、10科、35属、52种,其中长江上游特有鱼类13种;鱼类区系包括中国平原、南方平原、南方山地、中亚山地、北方平原和晚第三纪早期6个区系复合体;其中,中亚山地区系复合体占优(40.4%)。安宁河不同河段Jaccard's相似性指数在0.12~0.47,鱼类群落相似性总体较低。根据IRI(100为优势种)指数计算结果,麦穗鱼(Pseudorasbora parva)、齐口裂腹鱼(Schizothorax prenanti)、红尾副鳅(Paracobitis variegatus)、西昌高原鳅(Triplophysa xichangensis)、斯氏高原鳅(Triplophysa stoliczkae)、东方高原鳅(Triplophysa orientalis)、鲇(Silurus asotus)和白缘鱼央(Liobagrus marginatus)8种鱼类为安宁河优势种。根据个体生物学测量,安宁河主要渔获对象规格较小,齐口裂腹鱼均重285.8 g/尾,红尾副鳅均重7.2 g/尾,鲫(Carassius auratus)均重78.3 g/尾,鲤(Cyprinus carpio)均重361.1 g/尾,鲇均重93.7 g/尾,表明可能存在过度捕捞现象。多样性分析显示,Margalef丰富度指数(R)在1.95~4.47,Shannon-Wiener多样性指数(H)在1.75~2.33,Pielou均匀度指数(E)在0.67~0.73。安宁河鱼类多样性相比同区域其它河流偏低,可能与安宁河鱼类群落受到各种干扰、生境异质性降低、鱼类群落已发生演替有关。对比历史资料,鱼类种类数从82种下降至52种,在不同区域的各分类阶元均有所减少,且有自上而下加重的趋势。水电开发、河道采砂以及资源不合理利用等是影响安宁河鱼类资源的主要因素。基于研究结果,建议尽快加强安宁河鱼类资源保护。     

我国观赏渔业发展现状分析及对策研究

文章在浅议我国观赏渔业发展现状及发展意义的基础上,分析了观赏渔业发展中存在的六大问题,并从五个方面提出了相应的对策和建议。     

曹娥江流域鱼类资源调查

近三十年来曹娥江流域水利工程建设、水域环境、渔业捕捞等影响鱼类生存的环境因素发生了较大的改变,迫切需要对流域内的鱼类资源现状重新进行调查研究。本研究于 2015~2018 年对曹娥江流域 9 个采集点的鱼类资源进行调查分析。结果表明,调查共获得鱼类 105 种,隶属于 13 目 26 科。其中,鲤形目种类最多,为 65 种,占总种类数的 61.90%,优势种为鲢、麦穗鱼和子陵吻虾虎鱼。曹娥江水域鱼类群落Shannon–Wiener多样性指数（H''）为 1.9718,Simpson优势度指数（λ）为 0.3297,Pielou均匀度指数（J''）为 0.4237,Margalef种类丰富度指数(D)为 10.5741。与《浙江省动物志?淡水鱼类》中记载的曹娥江鱼类调查结果比较,本次调查获得鱼类中肉食性鱼类比例减少,杂食性鱼类比例增加,同时 Shannon–Wiener多样性指数（H''）和Pielous均匀度指数（J''）下降。这一结果表明,与上世纪九十年代相比,近年来曹娥江流域鱼类群落结构的复杂性降低,其稳定性降低;鱼类生物多样性下降提示曹娥江鱼类资源正处在衰退之中。因此,曹娥江流域仍需采取有效措施,进一步加强流域内鱼类资源保护。     

Lessons from Two Case Studies of Implementing Traceability in the Dried Salted Fish Industry

The traceability practices in two companies representative of those in a supply chain—one a producer of wet salted cod, the other of dried salted cod—were systematically investigated by a standard procedure. Neither company retained batch identities for all steps in the production process, and so, they did not have an effective traceability system. Although production of dried salted fish is challenging due to the many transformations taking place during production, the use of the basic technique of applying and recording unique identifiers could have provided a traceability system from delivery of wet fish through to the final dried product. This study focused on the critical points for traceability during production of both wet and dried salted fish and the practical challenges this presented.     

中国大陆鱼粉市场状况分析

就中国大陆鱼粉市场整体状况,分别从国内鱼粉生产状况、进口状况和鱼粉流通及市场价格变化状况进行了分析,希望有助于相关企业和部门的生产与管理。     

玛可河珍稀鱼类资源现状与保护对策

玛可河为大渡河主要干流及正源,近年来,自然环境的变化、人类活动的逐渐增多,玛可河珍稀鱼类资源生存环境受到威胁。本文分析了玛可河鱼类资源现状及生态环境所面临的问题,提出了保护对策,为修复玛可河珍稀鱼类资源、改善玛可河水域生态环境提供了措施。     

云南境内南盘江水系鱼类种质资源现状及保护对策

为了解南盘江鱼类资源现状,保护和恢复南盘江鱼类多样性,2008年6月至2010年3月,对云南省境内南盘江鱼类现状进行实地考察,结合中国科学院昆明动物研究所馆藏标本和历年相关记录,分析南盘江鱼类种质资源现状。结果表明,云南境内南盘江及其附属湖泊共有鱼类8目、20科、71属、160种;其中,土著种137种,特有种93种,外来种23种。鲤科鱼类最多,有94种,占鱼类总数的58.8%,其次为条鳅科32种,占总数的20.0%,爬鳅科7种,占总数的4.4%。南盘江鱼类种类众多,但由于人为影响,河流污染比较严重,目前已有24种鱼类被列为濒危种类。分析南盘江近两年的鱼类种质资源现状,发现土著种类的数量大幅下降,这与南盘江河流环境恶化和水电开发力度增大密切相关。