Marine Aquarium Research Articles

Case Report: Cryptocaryonosis in Indian Ocean Oriental Sweetlips (Plectorhinchus vittatus) Fish at the Closed System Quarantine of the Jakarta Aquarium and Safari

Cryptocaryon irritans, known as cryptocaryonosis disease infection in fish, is a significant problem for aquarists because they not only cause the disease but also lead to high mortality in the aquarium population. This case report aims to identify Cryptocaryon irritans infection in four Indian Ocean oriental sweetlips at the Jakarta Aquarium and Safari. Before they died, a total of four fish showed signs of weakness, scratching, excessive mucus, and pale gills. The diagnosis was confirmed through clinical assessment, physical examination, and microscopic analysis of skin scrape and gill clip samples, which revealed the presence of numerous trophonts (the young immature stages) of C. irritans. These findings underscore the importance of vigilant monitoring and prompt intervention to mitigate the impact of C. irritans, especially on marine aquarium fish populations.

Generation of the First Transgenic Line of the Iconic Coral Reef Fish Amphiprion ocellaris.

The common clownfish, Amphiprion ocellaris, is an iconic coral reef fish, ubiquitous in the marine aquarium hobby and useful for studying a variety of biological processes (e.g., mutual symbiosis, ultraviolet vision, and protandrous sex change). Recently, CRISPR/Cas9 methods were developed for knocking out specific genes for mechanistic studies. Here, we expand the genetic toolkit for A. ocellaris by creating the first transgenic line using the Tol2 transposon system. Fertilized eggs were co-injected with Tol2 transposase mRNA and a plasmid encoding an elongation factor-1α (Ef1α): green fluorescent protein (GFP) cassette at various concentrations, needle tip dimensions, and timepoints post-fertilization. We compared various injection parameters and sterilization methods to maximize the survival of injected eggs. F0s (n = 10) that were genotyped GFP + were then raised to 6months of age and crossed with wild-type (WT) females to confirm germline transmission. F1 offspring were also raised and crossed in the same manner. The highly efficient Tol2 transposon system resulted in a 37% rate of transgenesis for surviving eggs amounting to a 2.7% yield of all injected eggs surviving and being GFP + (n = 160). Of these, 10 were raised to adulthood, 8 spawned, and 5/8 (62.5%) produced GFP + offspring. Further, two F1s crossed with WT females produced 54.2% and 44.6% GFP + offspring respectively, confirming the creation of a stable line. This is, to our knowledge, the first generation of a transgenic line in any coral reef fish. The ability to express transgenes of interest in the iconic anemonefish opens the door to a new era of exploration into their fascinating biology.

Year-round natural spawning, early ontogeny, and larval rearing of the painted sweetlips, Diagramma pictum (Thunberg, 1792) in a hatchery: Potential as a new species for mariculture

The painted sweetlips, Diagramma pictum, is an important species for commercial fisheries, game fishing, and the marine aquarium trade. However, limited knowledge is available about the captive breeding and early developmental stages of this species. This study presents the first report on natural spawning, early ontogeny, and appropriate rearing conditions (temperature, salinity, and initial prey) for larviculture of D. pictum. Natural spawning of D. pictum in captivity was observed year-round for two years, from 1 June 2019 to 31 July 2021. During this 792-day period, females produced 127 spawns, with 77.2% ± 27.2% resulting in fertilized eggs. The median fecundity per spawn was 841 eggs with an interquartile range of 1173 eggs, and the average hatch rate was 59.3 ± 22.0%. Fertilized eggs were spherical, buoyant, and had a diameter of 0.78 ± 0.02 mm. Embryonic development lasted 14 h and 30 min at 28.0 °C. Newly hatched larvae measured 1.81 ± 0.20 mm in total length (LT), with 26 myomeres and an oil globule in the ventroanterior area of the yolk sac. Additionally, the ultrastructural observations of the micropyle, accessory openings, neuromast, and head spines of eggs and early larvae were reported for the first time. At 3 days post-hatch (dph), the larvae measured 2.59 ± 0.16 mm LT at full yolk sac and oil globule resorption. First feeding was noted at this stage, as evidenced by the expansion of the digestive tract filled with live feed. The juvenile stage was reached by 25 dph, and juveniles had an average length of 32.54 ± 2.17 mm LT. Based on hatch and survival activity indices (SAI), we propose optimal water quality parameters for D. pictum larval rearing as a temperature of 26–28 °C and a salinity of 32–33 psu. In the first feeding experiment, survival rates were not significantly different between feeding treatments R (Brachionus rotundiformis; 5 rotifers mL−1) and R + C (B. rotundiformis; 4 rotifers mL−1 + Calanopia elliptica; 1 nauplii mL−1), but both were higher compared to treatment C (C. elliptica; 2 nauplii mL−1) at 9 dph. Our study emphasizes the importance of simultaneous consumption of rotifers and copepods as vital initial prey for the first feeding larvae of D. pictum. Additionally, this co-feeding may enhance larval development through an additive effect. These results demonstrate the potential for establishing captive breeding programs for this species.

DESAIN DAN PEMBUATAN PROTOTIPE CARLSON SURGE DEVICE (CSD) UNTUK BUDIDAYA KARANG HIAS

As the interest in marine aquariums increases, so does the demand for ornamental corals. One of the parameters needed for coral growth is water flow. The Carlson Surge Device (CSD) is a tool that can generate water currents similar to natural sea currents found in coral reefs. This research aims to create a CSD that is easy and inexpensive to produce, so it can be widely applied in ornamental coral cultivation tanks by the community. By optimizing the cultivation of ornamental corals, it is hoped that the damage to coral reef ecosystems caused by illegal coral harvesting in nature can be minimized. This research uses an experimental method by testing PVC pipe diameters of 1 inch, 1.5 inches, 2 inches, and 2.5 inches. The CSD design created has reservoir dimensions with a diameter of 36 cm and a height of 35 cm, and uses PVC pipes with an inner pipe length of 20 cm and an outer pipe length of 44 cm. The results of this study show that the use of 2.5-inch diameter PVC pipes can produce a water flow rate of 0.28 m/s, which is suitable for coral growth, while the water flow produced by other pipe diameters is still too strong. These results indicate that the CSD prototype that has been made is suitable for application in ornamental coral cultivation tanks.

Life-history of the spiny butterfly ray, Gymnura altavela (Chondrichthyes: Myliobatiformes), kept under human care in a marine aquarium.

The Rio de Janeiro Marine Aquarium (AquaRio) is the first to successfully maintain and reproduce the spiny butterfly ray (Gymnura altavela), providing unique information about the species' biology. Seven rays were kept in captivity between 2018 and 2023, two captured on the southeastern coast of Brazil and five born in the aquarium. The applied abiotic conditions and nutrition allowed for the survival, growth, and reproduction of these individuals. Growth parameters (asymptotic disk width-DW∞ and growth coefficient-k) were estimated based on the von Bertalanffy model using the Fabens method for males and females separately. The best models estimated DW∞ = 106.47 cm and k = 0.396 for males and DW∞ = 172.2 cm and k = 0.190 for females. Sexual dimorphism was corroborated, with females reaching larger sizes and presenting slower growth rates than males. The estimated k values were higher than those estimated for rays of similar size to G. altavela in the natural environment, probably due to the constant water temperature (around 25.5°C), food abundance, low population density, reduced predation rates, and high water quality in the captive environment. A comparison of the captivity findings with other studies on G. altavela age and growth in the Atlantic and Mediterranean indicates a broad phenotypic plasticity regarding growth. Three G. altavela reproductions were recorded, with size at birth appearing to be a key factor for pup's survival. Behavioral pattern observations associated with reproduction are also described, encompassing chasing and copulation, whereas the species' internal morphology is described through coelomic cavity ultrasound scanning.

An Updated Review of the Marine Ornamental Fish Trade in the European Union

Wild-caught fish from coral reefs, one of the most threatened ecosystems on the planet, continue to supply the marine aquarium trade. Despite customs and veterinary checks during imports, comprehensive data on this global industry remain scarce. This study provides consolidated data on the largest import market by value, the European Union (EU): a 24-million-euro annual trade value, detailing the main exporting and importing countries, as well as the species and families of the 26 million specimens imported between 2014 and 2021. A watchlist alert system based on the number of specimens traded, import trends, and vulnerability index according to FishBase and the IUCN Red List conservation status is presented, providing key information on which species should require closer scrutiny by authorities. While the European TRAde Control and Expert System (TRACES) electronically monitors the movement of live animals to respond quickly to biosecurity risks, one-third of marine ornamental fish imported lack species-level information. With minor adjustments, TRACES holds the potential to significantly enhance data granularity and the monitoring of wildlife trade, with marine ornamental fish being an interesting case study to validate this approach.

Catching Dory: selling aquarium fish supports coastal livelihoods in Indonesia

The global marine aquarium trade has created new local markets across the planet, including in Indonesia, now the second-largest exporting country of marine aquarium fish in the world. Participating in the global aquarium trade has been touted as a potentially sustainable addition to fisher livelihoods, but scant data exist showing the numbers of fish coming off the reef and how those fish contribute to income. To determine how participants in the trade incorporate aquarium species in their livelihoods, we examine source-level aquarium fish collecting and trading data in the Banggai Archipelago, a region in Central Sulawesi that has become a significant source for popular aquarium, also known as ornamental, fish species. Using a sustainable livelihoods lens, we examine this data to understand how participants in the aquarium trade both contribute to as well as benefit from the trade and consider how their participation relates to emerging Blue Justice principles. From one year of buying and selling data at the fisher, intermediary buyer, and regional trader levels, we show that catching and selling fish for the aquarium trade represents an average of nearly 20% of their gross annual income and provides added diversity and flexibility to fisher and trader livelihoods in the region, especially during seasons of rough weather. We suggest that managers of an impending marine protected area in the region would do well to consider how to sustain these livelihood benefits.

Do Sustainably Reared Marine Sponges Represent A Potential New Product in Aquariology? A Citizen Science-Based Approach

Marine sponges have historically been targeted for different purposes, mainly as bath sponges or more recently as a source of bioactive metabolites. However, their use as ornamental species for aquariology is less thoroughly studied. In light of the rise in the importance of sustainable production systems and to valorize the biomass obtained from them, this work assessed the market potential of sustainably reared marine sponges in Italian aquariology. Information was obtained by means of an anonymous questionnaire distributed using social media and printed QR codes targeting Italian aquariophily groups. A total of 101 people from almost all Italian regions participated in the study. Among the people with marine aquariums, almost two-thirds had marine sponges (obtained mainly from fishing discards and trusted shops), and those without them stated that there was no availability in the specialized shops. However, when people were asked about a hypothetical change in purchase intention or frequency of these invertebrates, 68.3% of the respondents showed a positive attitude toward the idea of acquisition. This study constitutes the first preliminary assessment of the valorization potential for sustainably cultivated sponges as ornamental species, which shows a promising prospective in the Italian aquariology sector.

First feeding of a marine ornamental fish, the White‐barred Goby Amblygobius phalaena: Investigating the optimal initial live feed organisms and optimal feeding density

AbstractObjectiveThe White‐barred Goby Amblygobius phalaena is a popular ornamental fish in the marine aquarium market. To achieve successful commercial production, efficient larval rearing techniques are crucial. Previous studies have achieved successful cultivation of White‐barred Goby larvae by using a combination of three live feed organisms—the ciliate Euplotes sp., the rotifer Brachionus rotundiformis, and the copepod Apocyclops royi nauplii—during the first feeding stage. However, the specific contributions of these live feed organisms to larval survival and growth remain unclear. Moreover, the optimal feeding density for the critical initial live feed organism has not been determined experimentally. In this study, we aimed to enhance the larviculture protocol for White‐barred Goby by introducing Portuguese oyster Crassostrea angulata trochophores and by addressing these knowledge gaps.MethodsLarvae were initially cultured through individual and combined feeding with four live feed organisms: Euplotes sp., Portuguese oyster trochophores, B. rotundiformis, and A. royi nauplii. The objective was to identify the optimal initial live feed organism during the first feeding stage by assessing the survival and growth performance of larvae. Subsequently, using this optimal live feed organism, larvae were cultured at four feeding densities (2, 5, 10, and 20 individuals/mL). Through evaluating feeding incidence, feeding intensity, survival, and growth performance, the aim was to determine the optimal feeding density for the selected live prey.ResultOur experiments revealed that White‐barred Goby larvae could consume both oyster trochophores and Euplotes sp. during the first feeding stage. However, larvae exhibited superior survival and growth performance when fed oyster trochophores. The optimal feeding density of oyster trochophores was determined to be 10 individuals/mL, while a feeding density as high as 20 individuals/mL resulted in decreased larval feeding incidence.ConclusionThese findings have significant implications for enhancing larval production programs for marine ornamental gobies and promoting their sustainable commercialization.

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.

The half-life of cyanide in the blood of the marine fish, Amphiprion clarkii after cyanide exposure

Cyanide fishing continues to be used in the Indo-Pacific region to capture live reef fish for use by the live fish food and marine aquarium trades. The deliberate release of this broad-spectrum poison in reef environments is one of many anthropogenic threats to coral reefs today. Although this capture method is illegal in most countries, regulating its use is challenging due to the difficulty in determining whether a fish was captured using cyanide. A reliable method to test if marine fish have been caught using cyanide has long been the goal of the marine aquarium trade, but to date no test has been validated on fish with known cyanide (CN) exposure. Additionally, there are little to no toxicokinetic data on CN metabolism following CN exposure for marine fish. In this study, we exposed 38 specimens of Amphiprion clarkii to cyanide (50 ppm for 45 s) and measured the concentration of cyanide in their blood over time to characterize the detoxification process. CN was isolated from the blood by microdiffusion and derivatized to the highly fluorescent ẞ-isoindole and then quantified by HPLC. The half-life of cyanide in the blood of the marine fish A. clarkii was found to be 3.1 ± 2.0 hrs. CN levels were seen to be slightly above control levels 1 day post exposure and below control levels 3 days post exposure suggesting that any test for CN exposure by measuring cyanide must be conducted soon after exposure. To our knowledge, this is the first direct measurement of cyanide in the blood of a marine fish following CN exposure.

Can the global marine aquarium trade (MAT) be a model for sustainable coral reef fisheries?

Globally, 6 million coral reef fishers provide ~25% of emergent countries' catch, but species have low value. The marine aquarium trade (MAT) targets high-value biodiversity, but missing data amplify draconian governance and demand for international prohibition. To stimulate sustainability and reef conservation investment, we generate a fiscal baseline using the first global analysis of numbers, diversity, and biomass of MAT-traded organisms. Each year, ~55 million organisms worth US$2.15 billion at retail are traded comparable with major fisheries, e.g., tuna. A sustainable MAT also requires overexploitation assessments. We identify 25 species/genera with "Extremely High" risk ratios and place the Indonesian and Sulu-Celebes Seas in the highest exploitation category. Despite predicted hobbyist number increases, unabated reef degradation and low governance will transform the MAT into an aquaculture-dominated industry decoupled from communities (i.e., culture located in importing countries). A "MAT-positive" future requires evidence-based management/governance, consumer education, and sustainable practice incentivization but can address the biodiversity and social and economic inequality crises.

Effect of fragment size on growth and survival rate of Sarcophyton sp.

The Sarcophyton sp. are very strong and dominant in many coral reef areas. Sarcophyton species are characterized by a distinct sterile stalk, a broad, flared, smooth, mushroom-shaped top, with a wide distribution and dominance in numerous coral reef areas extending from the Red Sea and eastern Africa to the western Pacific Ocean. They are cherished in marine aquariums for their diverse colors and adaptability. However, their excessive exploitation has significantly impacted resources and disrupted the balance of the soft coral biome that inhabits coral reefs. The objective of the current study was to assess the impact of fragment size (0.5 × 0.5; 1.0 × 1.0; 1.5 × 1.5; 2.0 × 2.0, and 2.5 × 2.5 cm) on survival rate, growth rate and time of attachment of coral Sarcophyton sp. in a closed seawater system. Each treatment involved three replicates with 20 cuttings per replicate, and the experimental period was 90 days. The experiment showed that the fragment size did not influence the growth rate of oral disc diameter, pedal disk diameter, and the time attachment of Sarcophyton sp. However, the size of the fragment affects the survival rate, height growth rate, and weight of Sarcophyton sp. colonies. These findings collectively suggest that the initial coral fragment size of 1.5 cm was suitable in laboratory conditions.

Live Microalgae-Based Diets as Enrichment to Improve the Nutritional Profile of the Calanoid Copepod Acartia tonsa (Dana, 1849) Nauplii

Most emerging species in marine aquaculture and the aquarium industry have a sensitive and small-mouthed larval stage, and their culture is very challenging due to a lack of appropriate early feeding protocols. The use of copepods has been widely recognized as a good alternative to traditional fish live feeds (rotifers and Artemia spp.), especially for new species targeted for the multibillion-dollar marine aquarium trade. However, most copepod culture trials are focused on biomass production, while their nutritional requirements and enrichment protocols remain scarcely known. The main objective of this study was to determine the dietary contribution of three microalgae-based diets, provided as a mono R (Rhodomonas salina) or binary I–R (Isochrysis galbana + R. salina) and T–R (Tetraselmis suecica + R. salina), on the biochemical composition (proximate and fatty acids (FAs)) and survival of the calanoid copepod Acartia tonsa (nauplii) versus the conventional rotifer Brachionus plicatilis throughout 96 hr exposure. Both live preys were characterized by the highest protein and total n-3 long-chain polyunsaturated FAs (LC-PUFAs) content when fed with the binary diet I–R compared to other treatments, although the nutritional value of A. tonsa nauplii was always much higher compared to B. plicatilis. In general, there was a wide difference in proximate and FAs composition between the two preys, denoting A. tonsa as better live feed in terms of capacity to retain n-3 LC-PUFAs, especially eicosapentanoic acid (20 : 5n-3) and docosahexanoic acid (22 : 6n-3). The present study highlights the nutritional profile of enriched A. tonsa nauplii and contributes to the production of high-quality live feeds, which may be able to reach the nutritional needs of new marine fish species during their larval development, as well as contributing to the improvement of A. tonsa culture.

Marine aquarium trade: an open door for invasions in Iceland

Marine aquarium trade: an open door for invasions in Iceland

Cletocamptus cubaensis n. sp. (Harpacticoida, Canthocamptidae) from Cuba with taxonomic notes on the species

Abstract A new species of harpacticoid copepod, Cletocamptus cubaensis n. sp., from a marine aquarium in Cuba, previously identified with the highly polymorphic Cletocamptus deitersi (Richard, 1897), is described herein. A revision of the Cuban material showed that, despite the morphological similarity to Cletocamptus deitersi, there are significant interspecific differences in several microcharacters that were not taken into account in the previous species determination, such as integumental sensilla and pores, and ornamentation of segments, mouthparts, swimming legs, prosome, and urosome. Additionally, some other differences were observed in the relative length and shape of the apophysis of the endopod of P3 in males, the armature complement of the second segment of endopod P2 in males (with four setae instead of three), the ornamentation and length of the caudal rami in both sexes, and the ornamentation of the anal operculum (with 8 spinules). Similarity to other species is discussed, along with brief comments on the morphological similarities and differences between the new species from Cuba and Cletocamptus nudus Gómez, 2005 recorded from Brazil and Colombia, C. schmidti Mielke, 2000 known from the Galapagos archipelago, and C. samariensis Fuentes-Reinés, Zoppi de Roa & Torres, 2015 from Colombia.

Assessment of Microplastic Degradation in Bottom Sediments Using Raman Microspectroscopy and Atomic Force Microscopy

The assessed degradation of microplastics from bottom sediments of the Laptev Sea, the Weddell Sea, the Chukchi Sea and Peter the Great Bay, Sea of Japan, was studied using Raman microspectroscopy and atomic force microscopy (AFM). The degree of amorphous-crystallinity of polyethylene terephthalate (PET) was determined by the ratio of Raman mode intensities (I1095 cm–1 / I1115 cm–1). Changes in the topography and mechanical properties of the surface of polymer fragments were studied by AFM methods. It has been shown that the degradation of PET found in the bottom sediments of the Laptev Sea affects mainly its crystalline phase. The amorphous phase of PET is affected to a much lesser extent or not at all. The same changes in the phase composition of the PET surface have been shown after plastic exposure in a marine aquarium in silty sand from the Amur Bay (Peter the Great Bay, Sea of Japan). AFM data show an increase in PET surface roughness and a decrease in elasticу modulus (Young’s modulus) in bottom sediment samples. Raman microspectroscopy also shows signs of degradation of cellophane fragments from the Weddell Sea, polyvinyl chloride (PVC) from the Laptev Sea, and polyethylene (PE) from the Amur Bay.

The environmental impact of keeping a tropical aquarium in Northern Europe.

Tropical fishkeeping is a popular practice in societies across the globe and involves recreating and sustaining an entire ecosystem in an aquarium within a domestic setting. The process invariably has an environmental impact, yet an assessment of this impact has previously been limited to the ecological consequences of harvesting fish from the wild or the release of non-native fish species. Provided here are the first estimates of carbon dioxide equivalent (CO2 eq) emissions produced from running a tropical aquarium across multiple countries in Northern Europe (France, Poland and the UK), along with water consumption. Estimates were produced in silico and are discussed in the context of freshwater and marine aquariums, calculated using example aquarium sizes of 50, 200 and 400 l. Using estimates from the UK, depending on size and running conditions, a tropical aquarium produces an estimated 85.3-635.2 kg of CO2 eq per year, equating to 1.6%-12.4% of the UK annual average household CO2 emissions, and uses 156-31,200 l of water per year, equating to 0.2%-30.1% of the UK annual average household water usage. Despite this, comparison with the CO2 eq of an average-size dog (127-1592 kg of CO2 eq per year) or cat (121-251 kg of CO2 eq per year), estimated from meat consumption alone, demonstrates that ornamental fishkeeping can be a more environmentally conscious pet choice. In addition, the majority of CO2 eq produced from tropical fishkeeping is generated from the energy consumption of aquarium equipment and as more national electricity grids begin to decarbonize, this estimate should decrease.

4-H Marine Aquarium Project Book: Youth Project Guide to Starting and Maintaining a Saltwater Aquarium System

A UF/IFAS numbered publication.

4-H Marine Aquarium Adult Partner Guide

This guide is designed to assist the adult partner with a better understanding of the Marine Aquarium Project Book, as well as enhancing youths’ learning experiences. Written by Prudence Caskey, and published by the Florida 4-H Youth Development Program, UF/IFAS Extension, May 2023.