Marine Ornamental Fish Research Articles

STRATEGI PEMASARAN UNTUK IKAN HIAS LAUT (MARINE) BERKELANJUTAN

<p class="Style4">This research aimed to identify effective sustainable marketing strategies for marine ornamental fish. The research was conducted in South Sulawesi waters over a 6-month period, from September 2022 to March 2023. Primary data were obtained through interviews with fishermen groups and related parties, such as traders/collectors, TPI officers, and Marine and Fisheries Agency officers. The data included the condition of marketed products, fish marketing system, and description of marketing channels in South Sulawesi waters. The analysis method used is descriptive method. One of the indicators used to measure marketing efficiency is ornamental fish price data, by comparing the price received by producers/fishermen with the price paid by final consumers (farmers' share). The results of this research are expected to provide guidance in developing sustainable marketing strategies that can increase the economic value and sustainability of the marine ornamental fish industry. The implications of this research are also expected to contribute to efforts to conserve marine ornamental fish resources in Indonesia.,</p><p><strong> </strong></p><p><strong><em>Key words:</em></strong><em> marine ornamental fish, marketing strategy, sustainability, South Sulawesi waters.</em></p>

DNA barcoding of the most common marine ornamental fish species spilled over from a small-sized marine protected area, Bali Barat National Park, Indonesia

Abstract. Wiadnya DGR, Kurniawan N, Hariati AM, Astuti SS, Paricahya AF, Dailami M, Kusuma WE. 2023. DNA barcoding of the most common marine ornamental fish species spilled over from a small-sized marine protected area, Bali Barat National Park, Indonesia. Biodiversitas 243: 47-54. Healthy coral reefs within a protected area may function as a source of recruitment to the surroundings through spill-over and export larvae. This study aims to generate a list of common species of marine ornamental fishes for the aquarium trade in Indonesia, mainly collected adjacent to Bali Barat National Park (BBNP). Lived-fish samples were collected from six fish collectors in two villages surrounding BBNP, Sumber Kima, Bali, and Bangsring, Banyuwangi. All species were checked by three active fishermen in both villages for confirmation of the most common species and not belonging to the target. A total of 82 separate groups out of 145 specimens were identified based on their morphological characters. All samples were then sequenced based on mitochondrial cytochrome oxidase subunit I (COI) gene amplification. The sequence read lengths for all the specimens were between 655 and 658 bp. All the findings from this DNA barcoding approach were in line with morphological species identification. Wrasses (Family: Labridae) were the most dominant (41 species) representing the group, followed by Pomacentridae (24 species), Acanthuridae (14 species), Pomacanthidae (14 species) and Gobiidae (10 species). Among the species, only green sergeant, Amblyglyphidodon batunaorum, belonged to the Vulnerable (VU) category based on IUCN criteria. The rest were either Least Concern (LC), Data Deficient (DD), or Not Evaluated (NE). It implied that no catch species were under fishing pressure except for the green sergeant. Considering a total of 28 target species by local fishermen (recorded in an earlier article), small-scale fishermen can easily catch more than 100 species in one trip. The results significantly contributed to the need to generate a list of common ornamental fish species specifically exported from Indonesia as an aquarium trade commodity.

The effectiveness of brood stock management in captive breeding of marine ornamental Fish

Nowadays, the trade in marine ornamental fish is growing to be a multimillion-dollar industry. Because marine ornamental fish are successfully being bred in captivity, the industry can flourish. The breeding process is progressively applied through collecting fish from their natural habitat, inventory and domestication. An important stage in the breeding process of marine ornamental fish is the efficient management of brood stocks. A considerable number of initial populations become one of the keys to success in breeding marine ornamental fish. The principle of high genetic diversity in populations at the beginning of the collection is also an important indicator of the sustainability of the breeding process. The study aims to evaluate the management of brood stocks for marine ornamental fish in captive breeding. The observed parameters are the number of brood stocks populations, effective population size, and the utility of inbreeding in a population. The success of its cultivation is determined by the genetic diversity in the basic population which needs to be monitored from the start of the captive program.

First report on the occurrence of two marine ornamental fishes (Acanthuriformes) from Northern part of the Bay of Bengal, India

First report on the occurrence of two marine ornamental fishes (Acanthuriformes) from Northern part of the Bay of Bengal, India

Recent advances in marine ornamental breeding and seed production at Vizhinjam Regional Centre of CMFRI India

The marine ornamental fish trading industry is an ever-expanding one, as indicated by its bolstering statistics, which amount to about US$ 300 million. Although the trade is booming, the natural habitats that foster these fishes, such as coral reefs, are steadily declining. One of the reasons for this is the overdependency of the industry on wild-caught fishes. To surpass this, the Central Marine Fisheries Research Institute (CMFRI) has developed hatchery technology for breeding marine ornamental fishes such as seahorses, clownfishes, damsels, and serranids. It began with the breeding of Hippocampus kuda. This progressed to breeding clownfishes such as Amphiprion chrysogaster, A. ocellaris, A. nigripes, A. peridarion, and A. ephippium and Premnas biaculeatus. Damsel fishes that were bred successfully include Chrysiptera cyanea, C. hemicyanea Neopomacentrus cyanomos, N. nemurus, and Dascyllus carneus. The recirculating aquaculture system (RAS) designed in the Vizhinjam Regional Centre of CMFRI is being used for broodstock development of serranids, tangs, squirrel fishes, and soldier fishes. A standard method was developed for captive breeding and hatchery rearing of anthias Pseudanthias marcia and P. squamipinnis in an advanced indigenous RAS system. The present article provides a bird’s eye view of the important research work done in India concerning marine ornamental fish breeding and reviews important breeding work carried out at Vizhinjam Regional Centre of CMFRI.

Evaluation of larviculture protocols for the Pacific blue tang (Paracanthurus hepatus)

Aquaculture of marine ornamental fish is an important tool that may help to provide sustainable alternatives to wild caught individuals. Many challenges are associated with marine ornamental aquaculture, especially during the larviculture process. Newly hatched marine larvae are often underdeveloped at hatch and require specific nutritional and environmental parameters for successful morphogenesis and ultimate metamorphosis into the juvenile stage. The Pacific blue tang (Paracanthurus hepatus) is a promising candidate for ornamental aquaculture due to its popularity in the aquarium trade and prior captive breeding success. However, improvements in culture methodologies, especially environmental and nutritional factors, is critical to viable commercial production. Seven experiments were conducted to determine appropriate green water culture conditions, photoperiod, and feeding protocols that best promoted survival, growth, and ingestion rate in early-stage P. hepatus larvae. Larval survival and feeding incidence were significantly increased when live microalgae was added to the culture system. The survival and feeding incidence of 3 days post hatch (DPH) P. hepatus larvae was greatest when the algae species Tisochrysis lutea was incorporated at a density of 300,000 cells/mL. The feeding incidence of 3 DPH larvae was not affected by prey type or prey density. When free amino acid feeding stimulants were added to the culture water, neither larval survival nor feeding incidence were improved. Lastly, the photoperiod that best promoted larval growth and survival was 16-h light: 8-h dark. Together, these results provide for improved larval survival in aquaculture and help move P. hepatus towards viable commercial production.

New Records of Neobenedenia girellae (Hargis, 1955) (Monogenea: Capsalidae) in Marine Ornamental Fish Imported to Yucatan, Mexico

We detected Neobenedenia girellae infections in 40 species belonging to 12 families of imported marine ornamental fish from a public aquarium in the Mexican state of Yucatan. A total of 348 fish specimens were examined for monogeneans in January 2018 to December 2020. Monogeneans were corroborated morphologically and molecularly with a partial sequence of 28S (region D1–D3) ribosomal DNA and analyzed in a molecular phylogenetic context in combination with other N. girellae sequences available in GenBank. The phylogenetic tree revealed that the specimen found consistently belonged to the N. girellae clade. High infection parameters were detected of N. girellae in most hosts. This identification is relevant to aquarists and aquaculturists in the Gulf of Mexico because N. girellae is considered highly pathogenic in confined fish. This work demonstrates that the importation of ornamental fish coupled with deficient sanitary measures (lack of quarantine areas in distribution centers) contributes to spread of parasites and their establishment within Mexico.

Growth and survival of Banggai cardinalfish (Pterapogon kauderni, Koumans 1933) reared with artificial microhabitat

The Banggai cardinalfish (Pterapogon kauderni), endemic to the Banggai Archipelago (Central Sulawesi), has been declared the Indonesian National Marine Ornamental Fish Mascot. Sea urchins (Diadema sp.) are a key P. kauderni microhabitat. The decline of urchin populations due to harvesting for human consumption has adversely affected P. kauderni populations. The purpose of the study was to develop artificial microhabitat from environmentally friendly materials (coir and cement) and to determine the effectiveness of this artificial microhabitat in terms of fish growth and survival. The research was conducted in July 2021 at the Water Quality and Aquatic Biota Laboratory, Tadulako University. Two treatments were used (P. kauderni with live urchin microhabitat = BBA; P. kauderni with artificial microhabitat = BBB) with 8 replicates. T-test analysis showed net growth in weight differed significantly (p<0.05) between treatments (higher in BBA), as did survival rate (higher in BBB), while net growth in length did not differ significantly. Based on the results, it was concluded that the sea urchin-like artificial microhabitat developed could be effective as a surrogate P. kauderni microhabitat, at least in a controlled environment, and shows promise for supporting the conservation of P. kauderni. The next stage will be trials in the natural environment.

Identifikasi Parasit pada Ikan Hias Air Laut di Balai Karantina Ikan, Pengendalian Mutu dan Keamanan Hasil Perikanan Denpasar, Bali

Indonesia memiliki ikan hias air laut dengan jumlah yang sangat beragam. Pengembangan dan prospek komoditas ikan hias di Indonesia mengalami peningkatan yang sangat pesat, khususnya selama pandemi covid 19 ini. Akan tetapi, dalam prosesnya tidak jarang pembudidaya mengalami kegagalan produksi akbitat serangan hama dan penyakit. Hal ini menjadi kendala dalam proses pemenuhan kebutuhan baik domestik maupun internasional. Sehingga, perlu tindakan karantina ikan untuk mencegah terjadinya penyebaran penyakit parasiter. Tujuan dari penelitian ini adalah untuk melakukan pemeriksaan dan identifikasi jenis parasit pada ikan hias air laut sebelum dilalulintaskan di Balai Karantina Ikan, Pengendalian Mutu dan Keamanan Hasil Perikanan Denpasar, Bali. Pemeriksaan parasit dilakukan dengan metode konvensional yaitu dengan melakukan pengerokan pada permukaan tubuh, insang, sirip, dan operkulum ikan untuk ektoparasit dan usus ikan untuk endoparasit. Selanjutnya dilakukan identifikasi parasite secara morfologis. Hasil pemeriksaan dan identifikasi parasit menemukan parasite jenis Dactylogyrus dan Balantidium pada insang; Benedenia pada sirip ekor; Archigetes, Spirocamallanus dan Hexangium dari usus. Kata kunci: Ikan Hias Air Laut, Parasit, BKIPM Denpasar

Characterizing the gastrointestinal development and digestive enzyme ontogeny of larval Amphiprion ocellaris

Clownfish (Amphiprion ocellaris) are the most recognizable and popular marine aquarium fish and are a key commodity for marine ornamental fish producers. Although these fish have been raised in captivity for decades, producers are still experiencing issues regarding larval survival, reliance on live feeds, and post-larval deformities. To improve the culture process, the ontogeny of larval development and digestive capacity should be elucidated. The morphological development, digestive enzyme ontogeny, and digestive tract development of A. ocellaris was examined in a 16-day trial. Standard microplate assays were conducted to quantify the activity of trypsin, lipase, and acid protease enzymes from 24 h before hatching to 15 days post hatch (DPH). Histology was used to visualize morphological changes in the digestive tract throughout the larval period. At hatching, A. ocellaris has functional eyes, an open mouth, and a coiled, differentiated digestive tract. Trypsin and lipase activities were detectable before hatching and increased significantly later in the larval period. Gastric gland formation was observed at 6 DPH, with stomach functionality occurring between 7 and 9 DPH, indicated by gastric gland proliferation and an increase in acid protease activity. The results from this study may be used to inform weaning protocols to maximize larval growth and survival while minimizing the use of costly live feeds.

Designer clown fishes: Unraveling the ambiguities

The global marine ornamental fish trade is dominated by wild collected fishes, and the contribution from hatchery production is less than 10% of the total. Hatchery production is considered to be the only long-term sustainable option to reduce the fishing pressure on the wild population and also to safeguard the delicate coral reef ecosystem, which houses most of the marine ornamental species. Among the hatchery-produced fishes that are being traded, clown fishes form a dominant group, and a recent addition to this list is the designer clown fishes, which are costlier than other clown fishes due to their rare and attractive color patterns. However, ambiguities about designer clown fish such as its production (wild caught, captive bred, or genetically modified) and taxonomic identity still exist among the general public and hobbyists, as scientific reports on these aspects have not yet been published, even though few aquaculture companies display the photos of designer clown fishes in their websites. The common names for designer clown fishes (such as Platinum, Picasso, and snowflake) have been given by the aquaculture companies/traders solely based on the color patterns or designs on the fish body. The paper describes in detail the production of designer clown fish through captive breeding, followed by elucidating the taxonomic identity of two easily distinguishable designer clown fishes, viz., Picasso and Platinum. Both classical taxonomic tools and molecular methods were employed to elucidate the taxonomic identity. The morpho-merisitic characteristics of Picasso and Platinum were similar to those of Amphiprion percula. The partial cytochrome c-oxidase subunit I (COI) sequences of Picasso and Platinum clown fishes were submitted to the National Center for Biotechnology Information (NCBI) GenBank with accession numbers MT947238 and MT947239, respectively, which had maximum similarity to sequences of A. percula already deposited in the NCBI GenBank. The designer clown fishes exhibited protandrous hermaphroditism with monogamous mating behavior. Their egg incubation period ranged from 7 to 8 days, and the larval rearing was carried out with live feeds such as rotifers and Artemia under the greenwater technique using microalgae, Nannochloropsis oculata. This paper can thus unravel the ambiguities related to the production of designer clown fishes as well as their taxonomy.

MAINTENANCE OF THE BUTTERFLYFISH Chaetodon striatus (PERCIFOMES: CHAETODONTIDAE) IN A RECIRCULATION SYSTEM

The hight extractivism of marine fish to supply the demand of the aquarium market has worried the researchers and, in this context,, the aquaculture consists of an alternative to the problem. The family Chaetodontidae represents one of the main families of ornamental marine fish and has not received enough attention on their cultivation research. Considering the absence of this information about the butterflyfish Chaetodon striatus, the present work had the objective of obtaining information about the species in captivity. The fishes were kept in tanks of 100, 200, 300 and 1,000 L, with 6 fishes in each tank, with 3 repetitions for each volume, totaling 72 individuals and were observed for 30 days, being offered living small invertebrates and frozen and fresh mussels for the feeding. Also, for the attempt of reproduction in captivity, two couples, collected directly from the sea, with the entry of only two adults in the trap at a time, were used. Each couple was acclimated in a 100 L tank and we observed their behaviors for 8 hours a day. There was no mortality in tanks of 300 and 1,000 L and, for feeding, small invertebrates and fresh mussels were well accepted. Some behaviors were observed, most of which were already described for chaetodontids. This is the first report of C. striatus in captivity and this contribution may provide subsidies for a future technologi­cal package.

Baseline study on the freshwater ornamental fish industry in Palawan, Philippines

The status of both freshwater and marine ornamental fish industries in the Philippines has been assessed in 2019; however, Palawan was excluded due to the unavailability of data with regard to the ornamental fish trade. Hence, this study collected baseline data on the freshwater ornamental fish industry specifically the distribution of freshwater ornamental fish hobbyists, socio-demographic profile of the respondents, the key players involved in the market chain, classification and number of fish species and strains involved, and the challenges (economic and scientific) and opportunities encountered by the key players which could be used for the improvement and development of the ornamental fish sector in Palawan. A poll was conducted in order to obtain information on the general location of the ornamental fish hobbyists in Palawan in which 77 individuals participated. An online survey form was then sent to participants, however, only 40 responded. The freshwater ornamental fish hobbyists were distributed in 11 localities of Palawan. Key players involved in the market chain of freshwater ornamental fish were categorized as producers, traders, and sellers. Twelve freshwater ornamental fish species with 83 strains/varieties were involved, dominated by the Siamese fighting fish and guppy. Economic and research problems were some of the problems cited by the key players.

Plastic Filtration and Decomposition According to Ricochet Filtering Mechanism Using Ideonella sakaiensis

Our oceans have been under immense stress due to the deposition and accumulation of marine debris, of which 80% are plastics. Of these, microplastics which are small plastic fragments measuring less than five mm, have been a real bane to the marine fauna, especially the ornamental fishes inhabiting coral reef regions. The multibillion-dollar marine ornamental fish trade depends on these fishes caught from coral reefs. It has often been found that these small fishes are severely affected due to the choking of their gills with microplastics as they are natural filter feeders. To curb the load of plastics in the oceans, and especially in the waters around coral reefs, this study aims to develop a small-scale solution, which could later be scaled up by increasing the size and number of each unit as required. The system has been inspired by the filter-feeding mechanism of manta rays as a basic model for the filtration module. The use of a bacteria named Ideonella sakaiensis, which has been known to decompose plastics inherently is the second level of ideation that has gone into the design. The whole system has been envisaged as a floating system, where the filtration units would be submerged under water and the design of the platform over water would have a provision for self-sustenance, apart from the obvious role in maintaining buoyancy. Each filtration unit has been designed to possess multiple layers of sieving, vortexing and cross-flow filtration with a batch of I. sakaiensis at the end of the unit. To maintain a unidirectional flow of water, a fan would be placed at the end of these filtration units. This system can be a solution to the accumulation of plastics in a localized environment and can be scaled up in terms of size and the number of units to cover a greater area and volume to reduce the menace of plastic pollution. This could be a unique and cost-effective answer to the loss of marine fauna, more specifically ornamental fishes to the curse of microplastics.

Socio-economic development of marine ornamental reef fish fishers in eastern Sri Lanka through the lenses of Human Development Index

Marine ornamental reef (MOR) fishery in Sri Lanka expanded to the commercial level only after the 1950 s. Although MOR fishery is contributing significantly to the socio-economic development of the country, studies are scarce to assess the socio-economic status of fishers engaged in the fishery. The present study aimed to assess the socio-economic development of MOR fisher communities in the Trincomalee district, which is considered a hotspot for the MOR fishery in Sri Lanka through the lenses of the Human Development Index (HDI). Fisher communities associated with reefs at Sampur, Pulmodai and Kuchchaweli in Trincomalee were comprehensively studied focussing on full-time reef fishers (n = 90). Results indicated that the fisher income was several folds higher than the minimum monthly wage of workers in the country (10,000 LKR, ≈50 USD). Higher income gained by MOR fishers (30,000–300,000 LKR, ≈150–1500 USD) was conspicuously reflected by having high human, physical and health capital, all of which resulted from high financial capital. Income showed slight variations amongst communities based on the species being fished. Consequently, study communities held high Schooling Index (SI), Health System Index (HSI) and Economic index (EI) all of which are modified sub-indices of the common HDI. Human Development Index linked to Ornamental Fisheries (HDIOF) which is the weighted sum of SI, HIS and EI shows a medium level development in the MOR fisher communities at Trincomalee. The present study affirms that HDIOF is a promising indicator to elucidate the socio-economic status of the MOR fisher communities in Sri Lanka.

Gyrodactylus (Monogenea: Gyrodactylidae) on marine ornamental fish Amphiprion percula from a marine aquaculture facility in Indonesia

Abstract. Sufardin, Sriwulan, Anshary H. 2022. Gyrodactylus (Monogenea: Gyrodactylidae) on marine ornamental fish Amphiprion percula from a marine aquaculture facility in Indonesia. Biodiversitas 23: 1023-1030. As a popular marine ornamental fish (MOF), clownfishes are widely traded globally due to their beautiful appearance and relative ease of maintenance in the aquarium. There is a large amount of literature on Amphiprion biology and ecology, but globally still lacks data on their parasites, especially about monogenean gyrodactylidae. The first investigation of Gyrodactylus on a marine ornamental fish was conducted during March-August 2019. The study revealed the occurrence of Gyrodactylus infection in clownfish Amphiprion percula from Indonesia. A total of 50 fish samples were collected from a fish farm located in Takalar, South Sulawesi, Indonesia. Parasitological examination using the smear method was performed on the skin, fins, and gills. Parasites on each individual fish were counted directly under a stereomicroscope. Morphological measurements of the monogeneans were performed using ImageJ 1.46r software. Parasite infestation data were analyzed statistically using the Kruskal-Wallis test and linear regression. Based on morphology, the parasites infecting A. percula were identified as Genus Gyrodactylus and resembled described parasites on fish from the black sea. The prevalence of Gyrodactylus spp. was 100% on the caudal fin and was classified as a very severe infection with a total of 1908 individual parasites, overall. This study shows the Gyrodactylus intensity range is 8-75 parasites/fish and categorized as moderate and severe intensity, which are 6-55 parasite/fish for moderate and 55-100 parasites/fish for severe infection. Parasite infestation was higher on the caudal fin than other organs and was significantly positively correlated with fish size. This first report on the occurrence of Gyrodactylus on Amphiprion percula from Indonesia adds to the knowledge on gyrodactylid host fishes and infestation patterns.

Marine Ornamental Aquaculture: Measure Towards Biodiversity Conservation and Livelihood Promotion

Marine ornamental fishes are associated with the coral reef ecosystem, and they possess attractive colours, shapes, behaviours and aesthetic values. In recent days, aquarium tanks with a variety of marine ornamental organisms could be seen in homes, public places and commercial complexes, due to the developments in aquarium technologies. This indicates how this industry has been customized and became a popular hobby around the world. Aquarium business supports significant livelihood for millions of coastal and island communities across the world. Using destructive methods involving explosives and toxic substances (cyanides) for the collection of marine ornamental fishes from coral reefs damage the ecosystem and its biodiversity. Hence, aquaculture of the marine ornamentals would be encouraged as an alternative. The culture of marine ornamental fishes could be elevated from the small-scale backyard system with local coastal and island communities to big scale enterprises, by adopting feasible technologies. This article presents the overview of aquaculture of marine ornamental organisms and marine ornamental trade. The suggestions made here are intended to inform decisions on marine biodiversity conservation and livelihood promotion in coastal and island regions. Marine ornamental fisheries have been projected as an opportunity to sustainably breed marine species for the aquarium trade, while simultaneously generating employment for local communities.

Microhabitat association and population status of the Luwuk introduced Banggai cardinalfish (Pterapogon kauderni Koumans, 1933) population

The Banggai cardinalfish Pterapogon kauderni is the Indonesian national marine ornamental fish mascot, and an object of national and international conservation concern. The endemic population of this species is limited to the Banggai Archipelago in Central Sulawesi, Indonesia and a few nearby islands in North Maluku. In addition, introduced populations have become established, mainly along ornamental fish trade routes. The National Action Plan for Banggai Cardinalfish Conservation (NAP-BCFC) calls for monitoring and management of all P. kauderni populations. A survey of the Luwuk introduced P. kauderni population was carried out in October 2021. Data were collected at three sites with established P. kauderni populations: the ferry harbour, public harbour (Teluk Lalong) and a recreational area on the nearby coast (Kilo 5). P. kauderni were recorded by microhabitat association and size class (recruits, juveniles, adults). Data collected were compared with data from previous surveys where available. With the exception of one group in a sea anemone at Kilo 5, all P. kauderni were associated with Diadema sea urchins (D. setosum at all sites; D. savignyi at Kilo 5). At Kilo 5 P. kauderni the population structure indicates the possible capture of market-sized juveniles. Overall abundance was also lower compared to the polluted but unfished harbours. The proportion of recruits was significantly negatively correlated with the ratio of adult P. kauderni to Diadema urchins. The results will inform regional legislation currently in preparation to support sustainable management of P. kauderni populations, habitat and microhabitat in Central Sulawesi, as well as contributing to NAP-BCFC targets.Keywords:Banggai cardinalfishEndangered speciesDiademaMicrohabitat,MonitoringOrnamental fisheryLocal regulation

Biosecurity and the ornamental fish trade: A stakeholder perspective in England.

The freshwater and marine ornamental fish industry is a primary route of hazard introduction and emergence, including aquatic animal diseases and non-native species. Prevention measures are key to reducing the risk of hazard incursion and establishment, but there is currently little understanding of the biosecurity practices and hazard responses implemented at post-border stages of the ornamental fish supply chain. This study addresses this knowledge gap, using questionnaires to collate information on actual biosecurity behaviours and hazard responses practised by ornamental fish retailers and hobbyist communities in England. Actual behaviours varied considerably within retailers and hobbyists, suggesting that reliance on preventative practices by individuals in the post-border stages of the ornamental fish supply chain is likely to be ineffective in minimizing the risk of hazard incursion and establishment. Resources should be allocated towards improving and enforcing robust pre- and at-border control measures, such as risk-based surveillance of ornamental fish imports at border controls. In addition, these findings should be used to implement targeted awareness-raising campaigns and help create directed training on biosecurity practices for individuals involved in the post-border stages of the ornamental supply chain.

Digestive system ontogeny and the effects of weaning time on larval survival, growth and pigmentation development of orchid dottyback Pseudochromis fridmani

Although live prey remain essential for most marine finfish larviculture, the larvae or young juveniles are ultimately weaned onto formulated feeds at foodfish and ornamental fish hatcheries. Understanding the development of larval digestive capabilities is crucial for optimizing weaning success. The present study used the digestive system ontogeny to interpret the effects of different weaning times on larval rearing of orchid dottyback Pseudochromis fridmani, a marine ornamental fish species. The study documented the ontogenetic digestive system development of P. fridmani larvae from hatching to 40 days post-hatching (DPH). The histological analysis showed that as a demersal spawning species, the newly hatched P. fridmani larvae possessed advanced gut development which allowed the onset of exogenous feeding soon after hatching. Most major larval gut morphological changes were completed by 13 DPH; however, the stomach and gastric glands were first observed between 32 and 36 DPH. At this stage, P. fridmani larvae were expected to acquire substantially improved digestive capabilities, and were likely capable of digesting formulated feed. In the subsequent experiment, P. fridmani larvae were weaned onto formulated feed from 20, 23, 26, 29, or 32 DPH over a three-day period of co-feeding with enriched Artemia; the control group were exclusively fed enriched Artemia until the end of experiment. The timing of weaning significantly affected the larval growth and pigmentation development rather than survival (mean: 44–64%). P. fridmani larvae weaned later tended to grow larger, and the control group grew significantly larger in length than all weaning treatments (p < 0.05). Interestingly, at the end of the experiment (40 DPH), none of larvae from the control obtained adult-type pigmentation despite their larger size. In contrast, the introduction of formulated feed appeared to stimulate pigmentation development in P. fridmani individuals with a clear trend of higher pigmentation completion by 40 DPH (mean: 62–97%) with earlier weaning. Overall, this study demonstrated that P. fridmani larvae could be weaned onto formulated feed from as early as 20 DPH, before the stomach and gastric glands were fully developed; indeed, the timing of adult-type pigmentation change in P. fridmani was also advanced by the introduction of the weaning diet.