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.
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.
The influence of supplementation of drum-dried flake feed with various levels of Daphnia sp. on the growth and fecundity of broodstock Xiphophorus helleri was evaluated. Weekly supplementation showed no measurable advantage over flake feed only. A direct correlation was demonstrated between fecundity and size of female fish when fed a formulated flake feed only. Fish fed a daily Daphnia supplement had a mean final weight of 5.97 g, feed conversion ratio of 1.33 and mean fecundity of 190 embryos per female, which was significantly higher than the yield from the non-supplemented or weekly supplemented treatments. Despite these differences, the number of young harvested during the experiment did not differ (P > 0.05) between treatments and this discrepancy was ascribed to parental cannibalism of new born juveniles.
The establishment of large numbers of ramets from any individual coral genet can be used as a valuable source of material for the trade in ornamental marine organisms and in physiological and ecotoxicological studies. Here we discuss the rationale and the applicability of rearing ex situ large numbers of nubbins (minute fragments, down to the size of a single polyp). Nubbins taken from colonies of the branching Red Sea coral Stylophora pistillata show high survivorship under ex situ conditions and fast growth rates (5- to 6-fold increase in polyp numbers within 3 months) of the basal plates which revealed a significant correlation between tissue surface area and polyp numbers. Nubbins from branch tips and mid branches grew at a similar rate, but growth was affected by different light regimens. This approach requires further experimentation to elucidate optimal conditions.
Following the construction of a large-scale public aquarium, we were presented with an opportunity to investigate how wild caught Caribbean reef fish respond to their first encounter with a novel environment. Within the constraints of this opportunity, we designed a behavioural study to determine the reef fishes' response to a new habitat in relation to their locomotory mode. Nine species of fish representing three locomotory modes: carangiform, sub-carangiform and labriform/sub-carangiform were observed over a four-week period following their first introduction to the aquarium. Fish activity levels and spatial distribution were quantified in relation to time since their first encounter with the novel environment. The most important result was that, regardless of locomotory mode or ecology, all of the species extensively explored the novel environment rather than settle on the first habitat that they encountered. This is a particularly interesting result for territorial species. More specifically, however, there were significant differences between species in activity through time. Carangiform activity level was lowest in the initial phases of an encounter with the novel environment subsequently rising to a stable level. The other species had variable activity throughout the study, but all of them exhibited a phase of low activity at some stage during the study. In terms of the fishes' use of the 2.5 million litres of water, six species utilised the whole of the aquarium based on a predefined zoning scheme. Although the initial activity level was low, carangiform swimmers used at least 90% of the zones in the early phases of an encounter with the novel environment and subsequently used all of the zones. Sub-carangiform species also used 100% of the zones by the end of the study. Three of the four labriform/sub-carangiform swimmers used a maximum of 90% of the zones. There was no significant difference between species in their use of the zones. However, each individual zone was subject to differential use by the fish. Owing to the extensive scale of the aquarium, we discuss the applicability of the behavioural results obtained to the natural environment in the context of the ecology of the species of fish studied.
Three commercially available fatty acid enrichment emulsions (DC Selco, DC DHA Selco and DC Super Selco) were used to enrich Artemia nauplii fed to seahorse, Hippocampus sp. fry. The emulsions varied in their n-3 highly unsaturated fatty acid (HUFA) composition. Total n-3 HUFA content ranged from 200 to 450 mg g-1 between the three emulsions while levels of eicosapentaenoic acid (EPA, 20 : 5n-3) and docosahexaenoic acid (DHA, 22 : 6n-3) ranged between 47–220 and 80–190 mg g-1, respectively. Survival and growth of seahorses at the end of the 30 day growth trial were greater in treatments receiving enriched Artemia. Seahorses receiving Artemia enriched with DC DHA Selco and DC Super Selco showed significantly (p < 0.05) greater mean survival (71.6 ± 6.0% and 78.3 ± 6.0%, respectively) than those receiving unenriched Artemia (48.3 ± 6.0%). Mean standard length was also significantly greater (p < 0.05) in fry fed DC DHA Selco and DC Super Selco enriched Artemia (20.2 ± 0.3 and 19.7 ± 0.3 mm, respectively) compared to those fed unenriched Artemia (18.1 ± 0.3 mm). The results show that dietary n-3 HUFA are essential for optimal growth and survival of Hippocampus sp. and, based on the fatty acid compositions of the enriched Artemia used in this study, indicate that the level of dietary DHA supporting optimal growth and survival is greater than 9.3 mg DHA g-1 dry weight.
The market for marine ornamentals encompasses all live marine species (fish and invertebrates) destined for the aquarium trade. In 1998, U.S. imports and exports were valued at approximately US $1.5 billion at the border (all dollar values cited in this paper are $US). In Florida, cultured freshwater and collected saltwater species accounted for $70 million and $4 million, respectively, in annual dockside revenue. To help explain Florida's marine landings and provide suggestions for future resource management and market campaigns that reflect the perceptions of the industry, a survey of wholesalers was initiated in 1999. Preliminary results indicate that there are several intermediate wholesale markets. Florida firms are closer to the supply as many also collect. Wholesalers in other states handle more freshwater product, are larger, and tend to import a larger share of their inventory. Consolidation is expected to continue, but niche markets for eco-friendly firms are expected to grow. In Florida, marketing strategies should focus on the observed higher survival rates and increasing supply of the popular invertebrate species. Many wholesalers are concerned about additional regulations that could reduce the number of collectors and thereby increase supply variability, a noted weakness of the Florida industry.
The International Marinelife Alliance (IMA) has been training collectors in the Philippines and Indonesia to use barrier-nets rather than sodium cyanide to capture marine-aquarium fish. Despite the training, collectors have been slow to switch to using nets because they can earn more using cyanide. A new Philippine export company has agreed to pay the collectors more for net-caught fish and to adhere to standards being set by the USA-based Marine Aquarium Council. The IMA is monitoring the collectors and conducting cyanide testing to certify that the fish are net-caught and totally cyanide-free. Clearance certificates now accompany shipments of these marine-aquarium fish being shipped to wholesalers and retailers associated with the American Marine Dealers Association (AMDA) situated in the USA and Canada. AMDA members are being surveyed to assess whether the net-caught fish are more cost competitive compared to cyanide-caught fish for the marine ornamental fish trade because of reduced mortality through the chain from reef to retailer.
The parasitic fish nematode Camallanus cotti has been reported from a number of freshwater fish species around the world. Its wide geographical distribution seems mainly to be the result of anthropogenic dissemination due to extensive ornamental fish trade. In most reports it is assumed that C. cotti's life cycle involves cyclopoid copepods as intermediate host and various freshwater fishes as final host. However, the species' relatively frequent and persistent occurrence in aquaria worldwide strongly indicates flexibility in its life cycle, i.e. the ability to infect the final host directly. The present study has shown that under aquaria conditions, without any presence of copepods, C. cotti is able to infect various phylogenetically distant fish species directly for at least three generations. It was further shown that the infective free-living first-stage larvae may survive for more than three weeks in the host-external environment and that their host-attracting behaviour is not precluding direct transmission to the final fish host. Any treatment for C. cotti under aquaculture or aquarium conditions should be directed towards both individual infected fish hosts as well as the free-living larvae on the substrate.
The marine ornamental industry relies almost exclusively on wild-caught fish, invertebrates, and live rock to meet the market demands of aquarium hobbyists. For the industry to expand, appropriate technologies are needed to mitigate disease problems and reduce the dependence on wild stocks. Biosecurity protocols and techniques for genetic improvement have recently been applied to the culture of penaeid shrimp for human consumption, and these approaches may be applicable to an emerging marine ornamental industry. Biosecure production systems for penaeid shrimp are being developed in response to disease problems and growing concerns about environmental pollution from pond effluent. Biosecure systems rely on minimal water exchange and provide shrimp farmers with an opportunity to move production away from the coastline. In addition to the development of biosecure production systems, researchers at the Oceanic Institute have established a selective breeding program for the Pacific white shrimp, Litopenaeus vannamei . To date, significant improvements in shrimp growth and disease resistance have been made through selective breeding. It is likely that advances in biosecure technologies and genetic improvement will be applicable to the culture of marine ornamental shellfish and finfish and will contribute to an economically viable and environmentally sustainable industry.
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.
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.
Artificial reefs may provide a useful tool to enhance production of marine ornamentals and to divert detrimental harvesting activities from sensitive natural habitat. The efficacy of this strategy depends, in part, on the extent to which artificial reefs contribute to new production (vs. attract fishes from natural habitat) and therefore benefit harvested populations on a local and regional basis. Here the attraction and production hypotheses and their application to marine ornamentals are presented. Specifically, it is discussed how the strength and timing of density dependence can affect the response of fish population dynamics to artificial reefs. In addition to this discussion, examples of density dependence in marine ornamentals and related reef fishes are provided. Based on this information, a simple conceptual model is presented to clarify the role of density dependence, and this is followed by a discussion on the use of artificial reefs in the management and production of marine ornamentals. Finally, unresolved scientific issues that remain to be addressed are provided.
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.
Three species of surgeonfish Acanthurus coeruleus (blue tang) (Block and Schneider), A. bahianus (ocean surgeonfish) (Castelnau), and A. chirurgus (doctorfish) (Block) were captured in the waters of the Florida Keys (24°03′N, 81°40′W). In total, 39 of these fish were captured between March and December of 1999. Items found in the stomachs of these fish were identified and analyzed for percent occurrence. These values were compared to percent occurrence values of the same items from random bottom transects taken at the point of capture to quantify any forage selectivity or avoidance behavior of these fish. A. bahianus selected for sand and chlorophytes and avoided phaeophytes. A. chirurgus also showed selection for sand and chlorophytes, while 58% of those sampled selected for phaeophytes and 42% avoided them. A. coeruleus avoided sand and selected for rhodophytes and chlorophytes. Phaeophytes were also selected for in 80% of A. coeruleus sampled. Understanding food preferences of free-ranging Florida surgeonfish may provide insight to improve nutritional management of captive herbivorous reef fish.
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.
Three protein levels (30%, 38% and 45%) at three different dietary lipid concentrations (6%, 8% and 12%) were used to formulate nine different diets that were fed for 60 days to 6–8 weeks old juvenile swordtails (Xiphophorus helleri). It would appear that a diet of at least 45% protein at a 6% lipid concentration is needed for the best specific growth rate (1.27% per day) and feed conversion ratio (2.50) at this specific growth phase in X. helleri. No ‘protein sparing effect’ was found when lipid concentration was increased at lower protein levels.
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.
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.
The extraction of coral reef organisms for the aquarium and curio trade is reported to be contributing to coral reef degradation. The total international trade and associated impacts are unknown, because data are collected only for organisms listed on Appendix II of CITES, which include stony corals, antipatharians and giant clams. CITES data indicate that trade in live stony coral and reef substrate (‘live rock’) increased by 15–30% each year during the 1990s, with most exports since 1992 from Indonesia and Fiji. Overall, 19% of all stony coral traded (by item) from 1985 to 1997 was live; 71kern-1pt% of this was traded between 1993 and 1997 (52% of total trade). Although tracking trade using information from the CITES Trade Database provides limited information (e.g., coral is reported to genus, and volume is reported by item or weight), the CITES mechanism promotes the development of strategies to protect resources. In response to CITES requirements, Indonesia developed a management plan for sustainable harvest of corals, but not for non-CITES listed species such as soft corals and fishes. Trade in hard and soft coral provides revenue for developing countries; however, in order to be of lasting value the industry must be developed with a conservation ethic. This requires support for international programs such as CITES, management plans for sustainable harvest, and improved enforcement.
