Marine Ornamental Species Research Articles

Retailer perspectives reveal knowledge gaps in the traceability of the scleractinian coral trade in Singapore

Scleractinian corals are key reef-builders in tropical marine ecosystems. Harvests of wild stocks for the global marine aquarium trade have raised concerns about unsustainable exploitation. While it is important to ensure that marine ornamental species are used legally and sustainably, it is challenging to trace them through the trade due to the fragmented and complex supply chain. Retailers can provide unique perspectives to narrow knowledge gaps as they interact closely with both suppliers and consumers. Through semi-structured interviews of retailers based in Singapore, we investigated their knowledge of the supply chain, trade practices, and consumer preferences. We also surveyed taxa available for sale at these brick-and-mortar aquarium shops. Our study revealed at least 42 genera from 14 families of scleractinian corals present across 20 shops in Singapore. Retailers displayed a lack of familiarity in coral provenance and trade regulations, suggesting that they have limited awareness of traceability along the supply chain. Import decisions were not guided by traceability and environmental sustainability, but instead were driven by demand and supply factors such as aesthetics, rarity, and availability. This underscores the need for more outreach and engagement efforts to raise awareness among commercial stakeholders towards improving traceability and sustainable management in the marine aquarium industry.

Transport conditions in the planktonic phase for seahorses Hippocampus reidi Ginsburg, 1933 (Teleostei: Syngnathidae)

Thousands of seahorses are traded every year as marine ornamental species. Although packing methods for live adult seahorses have already been addressed, there is no information on the transportation of juvenile seahorses. Thus, this study aimed to evaluate the possibility of packing and transportation for newly-birthed seahorses. Three batches of newborn long-snout seahorses Hippocampus reidi were transported in three independent events from Ubatuba, north coast of São Paulo, to the city of São Paulo, covering 248 km in each trip, with an average duration of 3.5 h. A mean of 350 offspring of one day old was distributed in 1 L containers with round borders at equal densities, provided with constant aeration by portable pumps. Aeration was kept so that large bubbles would create an ascending flow keeping juveniles in suspension throughout transportation. Values of survival achieved in this study, even after 10 days post-transportation, were surprisingly high, reaching over 70%. No significant shift in water temperature, pH, or salinity was observed for any transportation events. For oxygen levels, although portable pumps were used, a drop of around 15% in DO level was recorded. In view of the trending ornamental fish market, considering the limited swimming capacity of newly born seahorses and that a great number of marine fish undergo a planktonic phase, this study provides important directions to a better understanding on seahorse transportation and yet, directions for the design of new transport methodology for an efficient shipping protocol for other species.

Prospecting the Photosynthetic Flatworm Symsagittifera roscoffensis as a Novel Fish-Feed

Symsagittifera roscoffensis is an intertidal Acoel flatworm that forms a symbiotic relationship with the alga Tetraselmis convolutae. Members of the genus Tetraselmis are known to have a high nutritional value and have been widely used to enrich intermediate prey for fish within the aquaculture industry; therefore, S. roscoffensis could be a good candidate as a trophic shortcut to deliver algal nutrition to fish. In this study, we investigated the likelihood of five ornamental tropical freshwater and six ornamental marine fishes to consume this worm, either as live feed or in freeze-dried form. We also tested the ability of S. roscoffensis to form a symbiotic relationship with alternative algal species, analysing the nutritional profile of S. roscoffensis when grown in different media. All the experimental fish consumed live worms to some degree, with the exception of one species (Meiacanthus grammistes); the response time to the worms ranged from 1.1–68.6 s for freshwater ornamental species to 1–24 s for marine ornamental species, and in most cases, this was comparable to or shorter than their response time to the reference diet Artemia. The fishes showed no negative effects after consuming the worms. We obtained similar results with freeze-dried worms in terms of the number of worms eaten, response time, and feeding time. Symsagittifera roscoffensis was able to form a symbiotic relationship with all the tested algal species of the genus Tetraselmis, but not with members of other genera. Worms grown in nutrient media (f/2 and f/4) had significantly higher contents of protein, pigments, and total and polyunsaturated fatty acids, including eicosapentaenoic acid (20:5n − 3) and α-linolenic acid (18:3n − 3), than those grown in seawater. These results show that S. roscoffensis was acceptable to many ornamental fish species, delivering key algal ingredients that are beneficial to fish health; hence, it is a promising alternative to conventional fish feeds for the ornamental pet trade.

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.

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.

Establishing larval feeding regimens for the decorator crab Camposcia retusa : Effects of live prey types and density on larval survival and development

Decorator crab Camposcia retusa is a popular marine ornamental species; however, it has never been bred previously. To establish a feeding regime for C. retusa larvae, which include two zoeal and a megalopal stage, three experiments were conducted. In all experiments, ≥60% of unfed 1st zoeal (Z1) larvae survived to the next stage, combined with the orange guts observed in larvae fed Artemia, suggesting Z1 larvae are facultative lecithotrophic. Experiment 1 evaluated the suitability of ss-type rotifer Brachionus rotundiformis as prey. Z1 larvae were fed rotifer at a density from 0 to 90 ind./ml. There was no significant difference in Z1 survival among treatments (56.7–68.3%, p > 0.05); therefore, ss-type rotifer is considered an unsuitable prey for the larvae. Experiment 2 examined the suitability and optimal density of Artemia nauplii, and co-feeding copepod Pavocalanus crassirostris with Artemia, for larval rearing. The larvae fed 10 Artemia/ml had the highest survival to megalopae (91.3 ± 3.1%, p < 0.05). However, high mortality occurred in megalopae, resulting in poor survival to the 1st crab stage (1.3%–12.5%) in all treatments (p > 0.05). Meanwhile, co-feeding copepods with Artemia showed significantly inferior survival and development to megalopae when compared to that of 10 Artemia/ml treatment. Experiment 3 evaluated the effects of Artemia enrichment on larval performance. The results suggested that Artemia enrichment did not improve larval survival or development. Based on our results, Artemia nauplii fed at 10 ind./ml throughout larval development appears to be appropriate for C. retusa.

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.

The European Union Is Still Unable to Find Nemo and Dory-Time for a Reliable Traceability System for the Marine Aquarium Trade.

Simple SummaryThe EU is one of the main markets for marine ornamental species. Their entrance into the EU, as well as their circulation between member states, is supposed to be highly regulated. Surprisingly, it is currently impossible to answer simple questions, such as how many Nemos and Dorys are imported each year into the EU, or where do they come from? This lack of knowledge is difficult to understand, as all these organisms enter the EU by air-shipping and must be controlled at customs offices in international airports. This scenario favors “business as usual” and does not allow to verify the claims on sustainability commonly made by the marine aquarium industry. However, the EU already operates a platform that may allow to collect such information in a reliable way and shed light on this blurry industry, the Trade Control and Expert System (TRACES). This platform can start by surveying marine ornamental fishes, so the EU can finally know how many Nemos and Dorys are being imported and where they are sourced from. If this approach works, marine ornamental invertebrates can also be monitored, and reliable databases can finally be assembled to document the marine aquarium trade in the EU.The EU is one of the main importers of marine ornamental species sourced from tropical coral reefs around the world. While the entrance of live organisms into the EU, along with their intra-EU circulation, is framed within stringent control mechanisms, to date, no reliable figures exist concerning which marine ornamental species are imported, in what numbers, and where they are sourced from. This lack of reliable data in the EU on the trade of marine ornamental species is puzzling if one considers that all these imported specimens must be controlled at customs offices located in international airports. Such data deficiency favors the prevalence of blurry supply chains and a “business as usual” mindset that hampers any serious effort to promote sustainability in the marine aquarium industry. To safeguard the collection of findable, accessible, interoperable, and reusable (FAIR) data, we suggest that the EU platform Trade Control and Expert System (TRACES) refines its surveillance on the trade of marine ornamental species. The detailed survey of marine ornamental fishes alone can be used as a proof of concept to validate the use of TRACES for this purpose and, if successful, it can later be expanded to all other taxonomic groups of marine ornamental species.

Management strategies to regulate the introduction of exotic ornamental fish, the silent invaders of freshwater ecosystems in India

Abstract Ornamental fish culture and aquarium keeping have become a booming sector worldwide. It has been observed that a number of stakeholders are involved in introducing exotic ornamentals in India as well, as the takers are interested on variants and new species. Most of the exotic ornamental fishes are also being domesticated in India, since the demand is readily fulfilled through adequate supply to the hobbyists. This sector provides livelihood option to many people and helps to earn millions of dollars to our country every year, however, the invasion of exotic ornamentals in our natural water bodies needs to be assessed, monitored and controlled with due attention as it is a staid menace to our biodiversity. Around 400 species / variants of exotic freshwater ornamentals and around 100 exotic marine ornamental species including invertebrates are found to have introduced in the trade. It is significant to note that an apparent violation in the trade is taking place by concealing the Government of India approval, which is given only for 92 species / variants of fishes for import. Further, as some of the freshwater ornamental fishes currently available in the aquarium trade have invaded through natural water bodies, their impacts need to be studied in detail. To deal with the situation, the proper precautionary approach should be implemented by adopting measures after having proper quarantine, meticulous risk analysis and strategic prevention methods as well. Combined efforts of industry stakeholders with different government agencies, academic and research institutions is required and a suitable protocol has to be formulated for permissible import, sustainable production, supply and management.

Marine amphipods as a new live prey for ornamental aquaculture: exploring the potential of Parhyale hawaiensis and Elasmopus pectenicrus.

Marine amphipods are gaining attention in aquaculture as a natural live food alternative to traditional preys such as brine shrimps (Artemia spp.). The use of Artemia is convenient for the culture of many marine species, but often problematic for some others, such as seahorses and other marine ornamental species. Unlike Artemia, marine amphipods are consumed by fish in their natural environment and show biochemical profiles that better match the nutritional requirements of marine fish, particularly of polyunsaturated fatty acids (PUFA), including eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids. Despite their potentially easy culture, there are no established culture techniques and a deeper knowledge on the reproductive biology, nutritional profiles and culture methodologies is still needed to potentiate the optimization of mass production. The present study assessed, for the first time, the aquaculture potential of Parhyale hawaiensis and Elasmopus pectenicrus, two cosmopolitan marine gammarids (as per traditional schemes of classification) that naturally proliferate in the wild and in aquaculture facilities. For that purpose, aspects of the population and reproductive biology of the species were characterized and then a series of laboratory-scale experiments were conducted to determine amphipod productivity, the time needed to reach sexual maturity by hatchlings (generation time), cannibalism degree, the effects of sex ratio on fecundity and the effects of diet (shrimp diet, plant-based diet and commercial fish diet) on fecundity and juvenile growth. P. hawaiensis, unlike E. pectenicrus, was easily maintained and propagated in laboratory conditions. P. hawaiensis showed a higher total length (9.3 ± 1.3 mm), wet weight (14.4 ± 6.2 mg), dry weight (10.5 ± 4.4 mg), females/males sex ratio (2.24), fecundity (12.8 ± 5.7 embryos per female), and gross energy content (16.71 ± 0.67 kJ g-1) compared to E. pectenicrus (7.9 ± 1.2 mm total length; 8.4 ± 4.3 mg wet weight; 5.7 ± 3.2 mg dry weight; 1.34 females/males sex ratio; 6.5 ± 3.9 embryos per female; 12.86 ± 0.82 kJ g−1 gross energy content). P. hawaiensis juvenile growth showed a small, but significant, reduction by the use of a plant-based diet compared to a commercial shrimp and fish diet; however, fecundity was not affected, supporting the possible use of inexpensive diets to mass produce amphipods as live or frozen food. Possible limitations of P. hawaiensis could be their quite long generation times (50.9 ± 5.8 days) and relatively low fecundity levels (12.8 ± 5.7 embryos per female). With an observed productivity rate of 0.36 ± 0.08 juveniles per amphipod couple per day, P. hawaiensis could become a specialty feed for species that cannot easily transition to a formulated diet such as seahorses and other highly priced marine ornamental species.

Development of early larviculture protocols for the melanurus wrasse Halichoeres melanurus

The minority of marine ornamental species in the global trade today are produced through aquaculture. Culture of these species through their fragile larval stage remains a major impediment to commercialization and research into optimizing production protocols is needed. To date, only five ornamental wrasse species have been successfully cultured and no commercial production exists. The melanurus wrasse (Halichoeres melanurus) was chosen as a candidate for the development of culture methodologies due to popularity in the aquarium trade and short larval duration. A series of experiments were conducted which investigated embryo incubation temperatures, algal density and shading practices during larviculture, as well as prey type, density, and availability. Survival, growth, and feeding incidence were response variables of primary interest.An inverse relationship was found between water temperature and embryo incubation period and temperatures of 25 and 28 °C produced highest survival and smaller larvae at hatch. Evaluation of melanurus wrasse larvae prior to first feeding established that algal densities ≥50,000 cells mL−1 or artificial shading resulting in ~300 lx, enhanced growth and survival. Melanurus wrasse first feeding trials revealed that algal densities of 300,000 and 500,000 cells mL−1, provision of Parvocalanus crassirostris nauplii (<75 μm), and prey densities ≥5.0 items mL−1 resulted in elevated larval feeding success. Continued investigation into larviculture techniques influencing growth, survival, and feeding success should establish methodologies leading to commercial protocols for the melanurus wrasse and other marine ornamental species.

Risk screen of lionfishes, Pterois, Dendrochirus, and Parapterois, for southeastern United States coastal waters of the Gulf of Mexico and Atlantic Ocean

The trade in marine ornamental fishes includes over 1800 species and is regarded as an introduction source for non-native fishes. Given this large pool of potential invaders, a targeted approach that evaluates risk for groups of fishes with demonstrated invasion history is both practical and feasible. In this way, proactive risk management frameworks can be used to identify risky species prior to introduction. Though the establishment of introduced marine ornamental species is uncommon, the invasion of Pterois volitans and P. miles in the western Atlantic Ocean has demonstrated the risks associated with the marine ornamental industry. These species, along with several other lionfishes, are regularly imported into the United States. We used the Aquatic Species Invasiveness Screening Kit to evaluate the risk of invasion for 14 species of traded lionfishes in the genera Pterois, Dendrochirus, and Parapterois for southeastern United States coastal waters of the Gulf of Mexico and Atlantic Ocean. The lionfish invasion is widely considered to be one of the worst marine invasions to date. Despite this, risk associated with the trade of lionfishes was estimated to be low, with notable exceptions. We identify Pterois russelii, Pterois lunulata, and Dendrochirus brachypterus as species with potentially elevated invasion risk. State and federal management agencies within the western Atlantic, Gulf of Mexico, and Caribbean should consider a detailed evaluation of these species to inform management action. This study is the one of the largest risk screening application of marine fishes to date and demonstrates the utility of prioritizing risk assessment of taxa found in pathways with related or otherwise similar species with previous invasion history.

Evaluation of conservation and trade status of marine ornamental fish harvested from Pangandaran Coastal Waters, West Java, Indonesia

Abstract. Nuryanto A, Bhagawati D, Kusbiyanto. 2020. Evaluation of conservation and trade status of marine ornamental fish harvested from Pangandaran Coastal Waters, West Java, Indonesia. Biodiversitas 21: 512-520. Pangandaran coastal waters are among the main supply areas of marine ornamental fish in Indonesia. However, no scientific data are available on the conservation and trade status of marine ornamental fish harvested in this region. This study aimed to evaluate the diversity, conservation, and trade status of marine ornamental fish species harvested from Pangandaran coastal waters. Fish were collected during surveys conducted in March, April, July, and September 2019. Species were identified by referring to the available guidance books. The conservation status was analyzed according to the IUCN database, whereas the trade status was evaluated based on the CITES database. A total of 107 marine ornamental fish species from 32 families and eight orders was obtained. The two out of these 107 species had an unresolved conservation status, whereas 24 species were listed as Not Evaluated, 80 species were listed as Least Concern, and one species was listed as Vulnerable by IUCN. Two species had an unknown trade status, whereas 104 species were listed as Not Evaluated and one species was listed in Appendix II of CITES. Our data prove that Pangandaran coastal waters have a high potential for supplying marine ornamental fish, with most of the species listed as having a Not Evaluated or Least Concern status. Most of the species identified were also categorized as having a Not Evaluated trade status.

Enhancing the colouration of the marine ornamental fish Pseudochromis fridmani using natural and synthetic sources of astaxanthin

This study quantifies the effects of astaxanthin concentration as a dietary supplement (25, 50, 75, and 100 ppm) and supplementation time (0, 14, 28, 42, 56, and 70 days) on the colouration of the marine ornamental fish Pseudochromis fridmani (Orchid dottyback), using natural (as vegetative Haematococcus pluvialis) and synthetic (as Carophyll Pink®) sources. The colouration of experimental fish was quantified every two weeks and compared to a commercial standard, which had the desired colouration of an intense magenta/raspberry. A model was subsequently developed to quantify the predicted minimum colour distance to the commercial standard for each dietary source and concentration of astaxanthin, where shorter distances are desired. Although colour improved with increasing concentration and supplementation time for either astaxanthin source, natural astaxanthin improved colour more effectively and at the end of the feeding trial, the colour distances between the two sources at each concentration, ranged between 3.87 ± 0.60 and 4.90 ± 0.56, where a colour distance above 3.5 is noticeable to a standard observer. The most effective treatment was natural astaxanthin at a concentration of 100 ppm for 70 days (colour distance from the commercial standard of 4.91 ± 0.69). Importantly, the predicted minimum colour distances for each source could be quantified for all treatments except for concentrations of 100 ppm of both sources, where the distances were outside the concentrations tested. Therefore, increasing the concentration of astaxanthin beyond the highest level tested in this study is predicted to further improve the colour of the fish. Demonstrating the combined, interactive relationship between the dietary concentration and time of supplementation on the colour of P. fridmani, provides a fundamental understanding of how astaxanthin affects colour in marine ornamental species, and encourages a shift away from synthetic ingredients.

Trade-offs between timing of metamorphosis and grow-out performance of a marine caridean shrimp juveniles and its relevance for aquaculture

Information on the aquaculture performance of marine caridean shrimp is still scarce when compared with that of freshwater species (e.g. Macrobrachium spp.) or penaeids. Moreover, most studies addressing shrimp aquaculture focus either larval performance or juvenile grow-out, with the vast majority overlooking the potential existence of carry-over effects from one life stage to the next. Such effects in phenotypic traits may be expressed when species undergo dramatic shifts, such as at metamorphosis. The present study evaluated the existence of potential trade-offs between the timing of metamorphosis and the grow-out performance displayed by juvenile marine caridean shrimp using Lysmata seticaudata, a marine ornamental species, as model. Larvae that delayed metamorphosis for longer periods (termed as late settlers – LS) gave origin to significantly larger sized post-larvae (7.37 ± 0.25 mm total length), than that displayed by early or middle settlers (ES and MS, 6.95 ± 0.28 mm and 7.02 ± 0.24 mm, respectively). However, at the end of the grow-out period juvenile shrimp originating from LS postlarvae displayed a significantly smaller TL (10.38 ± 0.82 mm) than that displayed from conspecifics originating from ES and MS (11.20 ± 1.02 and 11.22 ± 0.62 mm, respectively). The larger size attained by L. seticaudata post-larvae originating from specimens that delayed metamorphosis (LS) is likely achieved by trading-off endogenous energetic reserves that, once allocated to delay the transition to benthic life will no longer be available to help fueling early juvenile growth. The present work suggests that a detailed record on the timing of metamorphosis can be a more reliable proxy to access the grow-out performance of juvenile marine caridean shrimp than postlarval size at metamorphosis. An optimal aquaculture of organisms with complex life-cycles, such as decapod crustaceans, relies on the detailed knowledge of each life stage performance, as the exposure to suboptimal conditions during early life stages may give origin to phenotypic traits that are carried-over and only displayed later in the life cycle (e.g. post-metamorphosis).

The little shrimp that could: phylogeography of the circumtropical Stenopus hispidus (Crustacea: Decapoda), reveals divergent Atlantic and Pacific lineages.

The banded coral shrimp, Stenopus hispidus (Crustacea: Decapoda: Stenopodidea) is a popular marine ornamental species with a circumtropical distribution. The planktonic larval stage lasts ∼120–253 days, indicating considerable dispersal potential, but few studies have investigated genetic connectivity on a global scale in marine invertebrates. To resolve patterns of divergence and phylogeography of S. hispidus, we surveyed 525 bp of mitochondrial cytochrome c oxidase subunit I (COI) from 198 individuals sampled at 10 locations across ∼27,000 km of the species range. Phylogenetic analyses reveal that S. hispidus has a Western Atlantic lineage and a widely distributed Indo-Pacific lineage, separated by sequence divergence of 2.1%. Genetic diversity is much higher in the Western Atlantic (h = 0.929; π = 0.004) relative to the Indo-Pacific (h = 0.105; π < 0.001), and coalescent analyses indicate that the Indo-Pacific population expanded more recently (95% HPD (highest posterior density) = 60,000–400,000 yr) than the Western Atlantic population (95% HPD = 300,000–760,000 yr). Divergence of the Western Atlantic and Pacific lineages is estimated at 710,000–1.8 million years ago, which does not readily align with commonly implicated colonization events between the ocean basins. The estimated age of populations contradicts the prevailing dispersal route for tropical marine biodiversity (Indo-Pacific to Atlantic) with the oldest and most diverse population in the Atlantic, and a recent population expansion with a single common haplotype shared throughout the vast Indian and Pacific oceans. In contrast to the circumtropical fishes, this diminutive reef shrimp challenges our understanding of conventional dispersal capabilities of marine species.

Determining live prey preferences of larval ornamental marine fish utilizing fluorescent microspheres

As the popularity of marine aquaria grows, the potential exists for increased harvest of marine ornamental fishes and invertebrates from the oceans around the world. Aquaculture may be an alternative source to wild capture fisheries if commercial production protocols can be developed for species of interest, however numerous impediments must be overcome. Experiments were conducted on the reef butterflyfish (Chaetodon sedentarius), Pacific blue tang (Paracanthurus hepatus), African moony (Monodactylus sebae) and golden trevally (Gnathanodon speciosus) to evaluate and define prey preferences at first feeding among the rotifer, Brachionus plicatiilis, the copepod, Parvocalanus crassirostris, and the ciliate Euplotes sp., by marking each prey with a different colored fluorescent microsphere. Prey preferences observed at the larval first feeding stage were species specific. Pacific blue tang larvae preferred rotifers above ciliates, and ciliates above copepod nauplii. African moony larvae preferred ciliates and nauplii equally over rotifers. Reef butterflyfish larvae preferred ciliates over rotifers and rotifers over nauplii. Golden trevally larvae preferred nauplii over ciliates, and ciliates over rotifers. Take together these data provide critical information which may aid in development of feeding protocols for marine ornamental species.

Reproduction, early development, and larval rearing strategies for two sponge-dwelling neon gobies, Elacatinus lori and E. colini

A major goal of the aquaculture industry is to reduce collection pressure on wild populations by developing captive breeding techniques for marine ornamental species, particularly coral reef fishes. The objective of this study was to develop a rearing protocol for two recently described species of neon gobies that are endemic to the Mesoamerican Barrier Reef: 1) Elacatinus lori; and 2) Elacatinus colini. First, the current study describes the reproductive behavior and larval development of both species. Second, it evaluates the effects of different rotifer and Artemia densities on the survival and growth of E. lori and E. colini larvae. Third, it compares the survival and growth of E. colini larvae fed wild plankton to those fed a combination of rotifers and Artemia. Once acclimated, pairs of E. lori began spawning in 53.2±12.4 d (mean±sd), while pairs of E. colini took only 12.2±10.3 d. E. lori produced more embryos per clutch (1009±477) than E. colini (168±83). E. lori larvae hatched 8.18±0.4days after initial observation with a notochord length of 3.67±0.2mm. In comparison, E. colini larvae hatched 6.8±0.4days after initial observation with a notochord length of 3.51±2.3mm. Both species settled as early as 28days post hatch at 9–9.5mm standard length, following the fusion of the pelvic fins to form a pelvic disc. During rotifer density trials, from 0 to 6days post hatch, there was no significant difference in survival or standard length between treatments fed 10, 15 or 20rotifersml−1 for either species. During Artemia density trials, from 6 to 14days post hatch, control treatments fed solely on 15rotifersml−1 had significantly higher survival than treatments that were fed rotifers in combination with 3, 6 or 9Artemiaml−1. Finally, E. colini larvae that were fed wild plankton had significantly higher survival and growth than those fed with a combination of 15rotifersml−1 and 3Artemiaml−1. The results of this study suggest that Artemia nauplii are not a suitable prey for E. lori or E. colini larvae. Our results demonstrate the feasibility of rearing E. lori and E. colini to settlement, and suggest that 10–20rotifersml−1 and wild plankton provide a viable starting point for optimizing the survival and growth of Elacatinus spp. larvae.

Optimizing packing of live seahorses for shipping

The packing and shipping of live marine organisms always poses a potential risk to their survival and well-being, with the costs associated with these practices being paramount for marine ornamental species value chains. The present study describes two experiments employing the longsnout seahorse Hippocampus reidi (~80mm) as a model seahorse species to optimize its packing methods for live shipping. The first experiment evaluated the combined effect of seahorse density (1 ind. per 300mL, 1 ind. per 450mL and 1 ind. per 600mL), transit time (24 vs. 48h), and use of an oxygen saturated atmosphere for packing (pure oxygen vs. compressed air). The second one evaluated the combined effect of water salinity (15, 25, and 35) and use of a substrate for packed specimens to hold onto it, at a density of 1 ind. per 300mL. Survival was 100% in all treatments in both experiments up to 48h after shipping, with ~90% of seahorses displaying a normal feeding behaviour immediately post-transportation. In the first experiment, no significant differences were found (P>0.05) in weight-specific total ammonia nitrogen (TAN) excreted in all treatments within the same transit time. At the end of the transit time, treatments with an oxygen saturated atmosphere displayed an oversaturation in dissolved oxygen (DO) concentrations, whereas those employing compressed air for 48h ended the experimental trial with a DO concentration above 80%. Water with a salinity of 15 promoted a significantly (P<0.05) lower decrease in pH, followed by water at a salinity of 25 and 35. The lower salinity employed may have reduced breathing frequency of seahorses during transport. The presence of a substrate significantly (P<0.05) decreased weight-specific TAN excreted, possibly due to stress reduction. Overall, H. reidi can be packed at a density as low as 1 ind. per 300mL for up to 48h, with the use of pure oxygen not being mandatory. Lower salinities and the use of substrate can enhance seahorse welfare when these are shipped over longer transit times without representing additional significant costs. Overall, the findings of the present study may allow traders to ship 3 times more live seahorses than they currently do without negatively impacting their welfare neither increasing associated shipping costs.

First Record of Captive Larval Culture and Metamorphosis of the Pacific Blue Tang, Paracanthurus hepatus

AbstractThe Pacific blue tang, Paracanthurus hepatus, is consistently among the top 20 marine ornamental species imported into the USA, with all specimens presently sourced from wild stocks. Captive culture of this species through metamorphosis has not been previously documented and fundamental information regarding reproduction, larval culture, and production techniques is scarce. This study aimed to elucidate methods that would advance our understanding and success with captive propagation of this species. A total of 50,000 eggs were collected from a single broodstock population and stocked in a 1000‐L tank. Beginning at 3 d posthatch (DPH), larvae were fed three times daily a diet comprised exclusively of copepod nauplii. At 12 DPH, enriched rotifers were first fed followed by powdered feed (20 DPH) and first instar Artemia (21 DPH). Large mortality events were observed at 7 and 20 DPH, corresponding with starvation and flexion, respectively. By 41 DPH, the majority of the remaining larvae began associating with the bottom of the culture tank. On Day 50, the first signs of blue pigmentation marked the beginning of metamorphosis. A total of 27 juvenile blue tangs were cultured during this trial. This effort represents the first successful culture of this species in captivity.