Hippocampus Erectus Research Articles

Complete mitochondrial genome sequence of the lined seahorse Hippocampus erectus Perry, 1810 (Gasterosteiformes: Syngnathidae)

The complete mitochondrial genome sequence of the lined seahorse Hippocampus erectus was first determined in this article. The total length of H. erectus mitogenome is 16,529 bp, which consists of 13 protein-coding genes, 22 tRNA and 2 rRNA genes and 1 control region. The features of the H. erectus mitochondrial genome were similar to the typical vertebrates. The overall base composition of H. erectus is 31.8% A, 28.6% T, 24.3% C and 15.3% G, with a slight A + T rich feature (60.4%).

Marine dispersal and barriers drive Atlantic seahorse diversification

AbstractAimTo investigate how marine barriers shaped the demographic history of Atlantic seahorses (Syngnathidae: Hippocampus).LocationAtlantic Ocean.MethodsRange‐wide sampling (n = 390) at mitochondrial and up to five nuclear DNA loci was carried out across the Hippocampus erectus species complex (H. erectus from the Caribbean/North America, H. patagonicus from South America and H. hippocampus from Europe and West Africa). Multi‐species coalescent and approximate Bayesian computation (ABC) frameworks were used to estimate support of competing biogeographical hypotheses and demographic parameters, including lineage divergence times, effective population sizes and magnitudes of population size change.ResultsWe identified four distinct lineages within the H. erectus complex. A posterior probability of 0.626 and corresponding Bayes factors ranging from 3.68 to 11.38 gave moderate to strong support for a basal divergence between South American populations of H. patagonicus and Caribbean/North American populations of H. erectus coincident with the inter‐regional freshwater outflow of the Amazon River Barrier (ARB). Estimates of historical effective population sizes and divergence times indicate that European and West African populations of H. hippocampus expanded after colonization from a more demographically stable Caribbean/North American H. erectus.Main conclusionsOur findings of trans‐Atlantic colonization followed by isolation across a deep oceanic divide, and isolation across a freshwater barrier, may demonstrate a contrast in marine divide permeability for this group of rafters. Demographic inference supports the establishment of an ancestral population of the H. erectus complex in the Americas, followed by the ARB splitting it into Caribbean/North and South American lineages at a time of increased sedimentation and outflow. Our estimates suggest that following this split, colonization occurred across the Atlantic via the Gulf Stream currents with subsequent trans‐Atlantic isolation. These results illustrate that rafting can be a means of range expansion over large distances, but may be insufficient for sustaining genetic connectivity across major barriers, thereby resulting in lineage divergence.

Dermatitis and systemic mycosis in lined seahorses Hippocampus erectus associated with a marine-adapted Fusarium solani species complex pathogen

During a 4 mo epizootic, 100% of 152 lined seahorses Hippocampus erectus in 3 separate groups died while in quarantine following shipment to a public aquarium. Twelve animals with skin depigmentation and ulceration were received by the Aquatic Pathology Service, College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA, for diagnostic evaluation. Microscopically, lesions in 11 seahorses included multifocal epithelial necrosis and ulceration associated with 2 to 7 µm diameter, branching, septate fungal hyphae, typically accompanied by deeper infiltration into underlying skeletal muscle. Angioinvasion, with vascular thrombosis and tissue infarction, was a prominent feature in multiple animals. Fungal invasion of one or more internal organs was observed in 4 animals. Hyphae appeared to course freely through tissues and elicited little or no inflammatory response. Fusariosis has been reported sporadically in fish and other aquatic organisms, but identification has often been limited to the genus level based solely on morphologic features. Morphologic characteristics of the fungus isolated from this case were consistent with the Fusarium solani species complex (FSSC), which includes over 50 members that can only be identified definitively using DNA sequence data. A 3-locus typing scheme identified the isolate as a distinct species/haplotype, designated FSSC 12-a, belonging to a specific lineage that appears adapted to aquatic environments and disease in marine animals. Empirical treatment with itraconazole failed to stop mortalities, and subsequent in vitro antifungal susceptibility data explained a lack of clinical efficacy for this agent. Effective treatment in human medicine has similarly been limited by poor susceptibility to several classes of antifungal compounds.

Lipid Metabolic Response, Peroxidation, and Antioxidant Defence Status of Juvenile Lined Seahorse, Hippocampus erectus, Fed with Highly Unsaturated Fatty Acids Enriched Artemia Nauplii

The aim of this study was to evaluate the effects of Artemia nauplii enriched with different concentrations of highly unsaturated fatty acids (HUFAs) on the lipid metabolic response, peroxidation, and antioxidant defence status of the lined seahorse (Hippocampus erectus) juveniles. Twenty‐day‐old juveniles were fed Artemia nauplii enriched with four different concentrations (0.0 µL/L [control, A], 13.5 µL/L [B], 27.0 µL/L [C], and 54.0 µL/L [D]) of HUFAs (two thirds DHA and one third EPA) for 30 d. The activities of lipase and lipoproteinlipase of the juveniles significantly increased with increasing HUFA concentration; however, the activities of malate dehydrogenase and lactate content decreased with increasing HUFA concentration. Alkaline phosphatase activity and pyruvic acid content were not significantly different among the three treatments and the control. Malonaldehyde content was significantly negatively related to the enrichment concentrations (in Treatments A, B, and C); however, it increased significantly in Treatment D. The activities of superoxide dismutase in Treatments A and B were significantly higher than that in Treatments C and D. Catalase activity increased significantly from the control to Treatment C, then decreased significantly in Treatment D. Glutathione peroxidase activities increased significantly with increasing concentration of HUFAs, and peaked in Treatment D. The results indicate that dietary HUFAs are able to modify some enzymatic activities, and moderate dietary HUFA supplementation significantly promotes lipid metabolism and reduces lipid peroxidation products by enhancing antioxidant defence in the juveniles. However, excess HUFAs may result in adverse effects on the enzymatic activities in the juveniles, which might be related to oxidative stress.

Sexual Dimorphism in Morphometry and Allometry of the Adult Lined Seahorse, Hippocampus erectus

Despite monogamous mating systems and size-assortative mating observed in many seahorse (Hippocampus) species, sexual dimorphism is nonetheless observed in some. This study documents morphometry and allometry of the adult Lined Seahorse, Hippocampus erectus, and examines sexual dimorphism in these measures. Males exhibit longer standard lengths, shorter trunks with isometric growth, and longer tails with positively allometric growth. In contrast, females demonstrate positively allometric growth of trunk length and isometric growth in tail length. There is no observed dimorphism in the weight–length relationship, but it is positively allometric. Sexual dimorphism of body parts suggests sexually selective pressures, with longer trunks in larger females accommodating developing ovaries, and longer tails hypothetically garnering advantages for larger males in courtship behavior (tail grabbing), gestation (supporting brood pouches), and intraspecific competition (tail wrestling). Though monogamous mating syste...

Neoplasia of Captive Yellow Sea Horses (Hippocampus kuda) and Weedy Sea Dragons (Phyllopteryx taeniolatus)

Syngnathidae is the family of fish that includes sea horses, pipefish, and sea dragons. To date, only a single publication has described neoplasia in syngnathids, a fibrosarcoma of the brood pouch in an aquarium-reared lined sea horse (Hippocampus erectus). From 1998 until 2010, the Toronto Zoo submitted 172 syngnathids for postmortem; species included the spotted or yellow sea horse (Hippocampus kuda), the pot-bellied sea horse (Hippocampus abdominalis) and the weedy sea dragon (Phyllopteryx taeniolatus). Seven neoplasms and two neoplastic-like lesions were identified from these cases. Under light microscopy, the neoplasms had morphological characteristics of a cardiac rhabdomyosarcoma, renal adenocarcinoma, renal adenoma, renal round cell tumors, which were likely lymphomas, exocrine pancreatic carcinoma, and intestinal carcinoma. Of these neoplasms, four had clear evidence of metastasis: the pancreatic and intestinal carcinomas and both round cell tumors. As syngnathids are highly fastidious animals, they can be difficult to maintain in captivity. In order to improve their husbandry, preventative and palliative care, as well as treatment, it is important to investigate and document the types of diseases affecting syngnathids.

The dynamics of reproductive rate, offspring survivorship and growth in the lined seahorse, Hippocampus erectus Perry, 1810

SummarySeahorses are the vertebrate group with the embryonic development occurring within a special pouch in males. To understand the reproductive efficiency of the lined seahorse, Hippocampus erectus Perry, 1810 under controlled breeding experiments, we investigated the dynamics of reproductive rate, offspring survivorship and growth over births by the same male seahorses. The mean brood size of the 1-year old pairs in the 1st birth was 85.4±56.9 per brood, which was significantly smaller than that in the 6th birth (465.9±136.4 per brood) (P<0.001). The offspring survivorship and growth rate increased with the births. The fecundity was positively correlated with the length of brood pouches of males and trunk of females. The fecundity of 1-year old male and 2-year old female pairs was significantly higher than that from 1-year old couples (P<0.001). The brood size (552.7±150.4) of the males who mated with females that were isolated for the gamete-preparation, was larger than those (467.8±141.2) from the long-term pairs (P<0.05). Moreover, the offspring from the isolated females had higher survival and growth rates. Our results showed that the potential reproductive rate of seahorses H. erectus increased with the brood pouch development.

Ichthyofauna used in traditional medicine in Brazil.

Fish represent the group of vertebrates with the largest number of species and the largest geographic distribution; they are also used in different ways by modern civilizations. The goal of this study was to compile the current knowledge on the use of ichthyofauna in zootherapeutic practices in Brazil, including ecological and conservational commentary on the species recorded. We recorded a total of 85 species (44 fresh-water species and 41 salt-water species) used for medicinal purposes in Brazil. The three most commonly cited species were Hoplias malabaricus, Hippocampus reidi, and Electrophorus electricus. In terms of conservation status, 65% of species are in the “not evaluated” category, and 14% are in the “insufficient data” category. Three species are in the “vulnerable” category: Atlantoraja cyclophora, Balistes vetula, and Hippocampus erectus. Currently, we cannot avoid considering human pressure on the population dynamics of these species, which is an essential variable for the conservation of the species and the ecosystems in which they live and for the perpetuation of traditional medical practices.

Growth and Survival of Juvenile Lined Seahorse ( Hippocampus erectus ) at Different Food Densities

To investigate the effect of Artemia nauplii with different densities on the survival and growth of Hippocampus erectus juveniles,newly hatched H.erectus juveniles were fed with Artemia nauplii for 50 days,which were divided into three groups [5 nauplii/mL(A),10 nauplii/mL(B) and 20 nauplii/mL(C)].The results show that the survival and growth of juveniles could not be explained by three food densities during the first 10 days.The survival of juveniles with 10 nauplii/mL and 20 nauplii/mL food densities were significantly higher than that with 5 nauplii/mL from day 20 to day 50(P0.05),but there was no significant difference found between the survival in treatments B and C.Additionally,the weight and height of juveniles in treatments B and C were significantly higher than that in treatment A on day 20(P0.05).The weight and height of juveniles in treatments A and C increased dramatically than that in treatment B from day 30(P0.05),and the difference in growth among the three food densities groups reduced on day 40,then the weight and height of juveniles in treatment A was higher than those in treatments B and C(P0.05).The weight gain(WG),condition factor(CF) and special growth rates(SGR) of the juveniles with three food densities were not significantly different on day 50.The pH and DO of water decreased with increasing of food density over 24 h,however,water quality was not deteriorated to become a major factor reducing the growth of the juveniles.Furthermore,the concentration of ammonia-N in treatment C was significantly higher than that in treatments

Criteria for assessing juvenile quality of the lined seahorse, Hippocampus erectus

Juvenile quality has been demonstrated to be the key for commercial fish production. Variations in juvenile quality leading to varying growth and mortality are often encountered and well documented in many marine fish species. It is valuable to discover simple and reliable indicators for assessing juvenile quality in fish aquaculture. In this study, we established criteria for evaluating the juvenile quality of the lined seahorse, Hippocampus erectus, a Chinese traditional medicine and popular aquarium species. We raised 18 batches for 45 days from birth to determine the potential criteria for assessing the juvenile quality of the line seahorse. There was a strong and significant correlation between survival through the fifth day and that on the day 45. By comparing the ratio of trunk width at 1/2 trunk length to trunk length (TW/TL) of dead and live juveniles during the first 5 days, we found that TW/TL is a reliable indicator of the juvenile quality, with the distinct threshold of 0.190.

Evoked potential audiogram of the lined seahorse, Hippocampus erectus (Perry), in terms of sound pressure and particle acceleration

The hearing sensitivity of the lined seahorse, Hippocampus erectus (Perry), was determined for both sound pressure and particle acceleration using the auditory evoked potential (AEP) technique. Hippocampus erectus demonstrates hearing sensitivity typical of historically characterized hearing generalist fishes, with best sensitivities below 600 Hz and maximum sensitivities of 105.0 ± 1.5 dB SPL (re: 1 μPa) and 3.46 × 10−3 ± 7.64 × 10−4 m s−2 at 200 Hz. The shapes of the audiograms for each modality are similar, suggesting relative similarity in sensitivity between modalities for a given frequency. In light of the importance of broadband sound in the acoustic landscape of this fish’s environment, and broadband conspecific sound production that may be used in intraspecific acoustic communication, audition to broadband sounds was also estimated. Maximum broadband sensitivity at 200 Hz is estimated to be 92.0 ± 1.5 dB SPL (re: 1 μPa) and 7.73 × 10−4 ± 1.71 × 10−4 m s−2.

A New Species of Myxosporean (Sphaeromyxidae), a Parasite of Lined Seahorses, Hippocampus erectus, from the Gulf of Mexico

Sphaeromyxa cannolii sp. n. is described from the bile ducts of aquaria-maintained lined seahorses (Hippocampus erectus) from the Gulf of Mexico. Spores of the new species are linear, 17-18 µm long and 5-6 µm wide, with flattened tips; polar capsules measure 4 × 3 µm. Routine necropsies of H. erectus following planned death revealed liver inflammation, bile duct obstruction, bile accumulation, and myxozoan parasites in the bile ducts of 11 of 40 animals sampled (27.5%). The presence of S. cannolii in an aquaculture setting should prompt keepers to carefully quarantine new animals and exclude annelid fauna, a potential intermediate host of myxozoans.

Growth and survival of juvenile lined seahorse, Hippocampus erectus (Perry), at different stocking densities

The lined seahorse, Hippocampus erectus (Perry), is an important species in both medicinal and aquarium trades. The aim of this study was to evaluate the effects of stocking density (1, 3 and 5 individuals L−1) on the growth performance and survival of the early-stage juvenile H. erectus. The height (HT), wet weight, weight gain (WG) and specific growth rate (SGR) were affected significantly by the stocking density during the 40-day study. The HT, WG and SGR of the seahorse at 1 and 3 juveniles L−1 were significantly higher than that at 5 juveniles L−1. The survival of juveniles at the three stocking densities was not significantly different at day 25 (90.3 ± 4.5%, 86.7 ± 4.2% and 86.2 ± 3.8% for 1, 3 and 5 juveniles L−1 respectively), but was significantly different at day 40 (87.8 ± 3.9%, 69.6 ± 4.2% and 52.9 ± 2.8% for 1, 3 and 5 juveniles L−1 respectively). For the early-stage juvenile H. erectus, we recommend a stocking density of 3 juveniles L−1, but the density should be reduced to 1–2 juveniles L−1 to avoid reduced and variable growth and high mortality after 25 days.

Sound, stress, and seahorses: The consequences of a noisy environment to animal health

We examined stress responses to chronic noise exposure in a popular aquarium fish, the lined seahorse (Hippocampus erectus). Thirty-two animals were housed individually in either loud (123.3±1.0dB re: 1μPa total RMS power at mid-water, 137.3±0.7dB at bottom) or quiet (110.6±0.58dB at mid-water, and 119.8±0.4dB at bottom) tanks for one month. Weekly behavioral observations were scored and compared between treatment means, as well as treatment variances, because stressed populations often exhibit increased variance in measures. At the end of each trial, animals were euthanized, assessed, and means and variances of the following measures were compared between treatments: weight change (ΔWt), change in Fulton condition factor (ΔK), hepatosomatic index, gonadosomatic index, leukocyte count and differential, packed cell volume, heterophil to lymphocyte (H:L) ratio, blood glucose concentration, plasma cortisol concentration, parasite presence/absence and number of organs infected, and presence/absence of bacterial infection.Among behavioral results, tail adjustments and reduced or variable percentage of time spent stationary were interpreted as irritation behaviors. Animals in loud tanks were more variable in the number of tail adjustments made; this difference was especially significant in week one, when loud tank animals also made significantly more adjustments. Animals in loud tanks also demonstrated greater variation in the percentage of time spent stationary in the first week. Variability in these measures subsided after the first week, presumably due to habituation. Piping and clicking were considered pathological and distress behaviors (respectively). Animals piped and clicked more variably in loud tanks; this variability was especially pronounced in week 4. Other behaviors were unremarkable.Among physiological results, animals in loud tanks declined in morphological indices more precipitously; these differences were significant in ΔWt and ΔK. Animals in loud tanks demonstrated significant and variable heterophilia and significantly higher and more variable H:L ratios. Plasma cortisol concentrations were higher among animals in loud tanks. Kidneys were significantly more affected by parasites in loud tanks. Other physiological measures were unremarkable.Seahorses exposed to loud ambient noise in aquaria exhibit primary, secondary, and tertiary stress responses at behavioral and physiological levels, necessitating allostasis at costs to growth, condition, and immune status. Aquarists and aquaculturists are thus advised to incorporate soundproofing modifications during design and set-up of facilities to improve fish health, and growth in culture.

Hearing ability of the lined seahorse (Hippocampus erectus).

The lined seahorse (Hippocampus erectus), a member of the family Syngnathidae (pipefishes and seahorses), occurs in coastal waters of the western Atlantic, Gulf of Mexico, and Caribbean Sea. This harmless species is listed as “vulnerable” on the International Union for the Conservation of Nature (IUCN) List of Threatened Species, meaning that it has a high risk of extinction in the medium‐term future primarily due to declines in population from targeted catch, bycatch, and degradation of habitat. However, because little is known about hearing in Syngnathids, it is difficult to assess potential effects of anthropogenic sound on these animals. In this study auditory evoked potentials (AEPs) were measured in four H. erectus specimens to determine hearing thresholds and bandwidth. Thresholds were determined using the staircase method with exposures to tone bursts between 50 Hz and 21.6 kHz. At low frequencies H. erectus had AEP thresholds similar to other bony fishes; however, at frequencies above 2 kHz its auditory sensitivity was similar to that of clupeiform species which detect ultrasound [Mann et al., J. Acoust. Soc. Am. (2001)]. The results of this study provide hearing data that can be used to understand potential effects of human‐generated noise on Hippocampus erectus and other seahorse species.

Polyculture of the lined seahorse, Hippocampus erectus Perry, 1810 with two species of macroalgae in aquaria

A two-month study was conducted to test the effects of macroalgae on the growth and survivorship of juvenile lined seahorse (Hippocampus erectus) in aquaria. Twenty-day old seahorses were cultured in the tanks with green alga Chaetomorpha linum, red alga Gracilaria tikvahiae, green plastic artificial plant (stargrass), and black plastic net, respectively. Increases in wet mass and standard length for the seahorses were significantly higher in the tanks with macroalgae than those without macroalgae. The seahorse survivorships in the two macroalgal treatments were also significantly higher than those of the two treatments without macroalgae. In the treatments with macroalgae, the DO and pH were higher than those without marcoalgae. During the experiment, the color of seahorses was changed to certain extent. In the green background (the treatments with C. linum and stargrass), 24.1%–28.4% of black seahorses decreased over time; whereas in the black (plastic net) or brown (G. tikvahiae) background treatments, 14.1%–16.3% of yellow seahorses decreased over time, for matching that of the background. Furthermore, the survival rate of seahorse was correlation with DO and pH, and strong correlation with standard length, wet mass and CF. Polyculture with macroalgae, survival rates of seahorse were higher than without macroaglae.

Effects of substrate color, light intensity and temperature on survival and skin color change of juvenile seahorses, Hippocampus erectus Perry, 1810

Seahorses are popular ornamental fish for marine aquaria, with more colorful individuals commanding higher prices. We investigated the effects of substrate color, light intensity and water temperature on the survival and skin color change of the juvenile seahorse, Hippocampus erectus. During the 6-week study, the juveniles cultured with substrates of mixed colors (green and orange, green and red) had higher survival and color change rates than those with a single color substrate (green, orange, red, or black, F 5, 18 = 2.764, F 5, 18 = 56.225, P < 0.05). Color change rate of the juveniles increased with increasing light intensity (500, 1000, 1500, 2000, 2500 and 3000 lx) with juveniles cultured at 500 lx had the highest survival rate (85.35 ± 5.18%). The wet weight, standard body length and age of the juveniles that began to change their skin color ranged from 0.054 ± 0.007 g, 3.12 ± 0.31 cm and 17.26 ± 2.23 days post partum (green and orange substrate mixture) to 0.082 ± 0.013 g, 3.68 ± 0.59 cm and 25.66 ± 6.21 days post partum (black) among the substrate color treatments; and from 0.043 ± 0.009 g, 3.09 ± 0.62 cm, and 14.57 ± 2.35 days post partum (3000 lx) to 0.067 ± 0.008 g, 3.87 ± 0.49 cm, and 18.41 ± 3.73 days post partum (500 lx) among the light intensity treatments. Survival rate and color change rate of the juveniles cultured at three temperatures (23 °C, 26 °C, and 29 °C) differed significantly after 5 weeks ( F 2, 9 = 11.053, P < 0.05). The juveniles cultured at the temperature of 29 °C had the highest color change rate of 80.43 ± 4.27%. These results demonstrate that appropriate mixed color substrate, light intensity and temperature can improve the survival and skin color change rates of the juvenile H. erectus, thus affecting their market value.

First occurrence of the lined seahorse Hippocampus erectus in the eastern Atlantic Ocean

A seahorse specimen from Banco Açores (Azores Archipelago) was identified using morphological and molecular genetic data as Hippocampus erectus. This specimen represents the first record of H. erectus in the eastern Atlantic Ocean, well outside its reported range, and may provide evidence of long-distance translocation in what are assumed to be relatively sedentary fish.

Effects of light intensity, stocking density, feeding frequency and salinity on the growth of sub-adult seahorses Hippocampus erectus Perry, 1810

This investigation examined the effects of light intensity, stocking density, feeding frequency and salinity on the growth of sub-adult seahorses, Hippocampus erectus and the development of the brood pouch in male seahorses. During the 8-week study, seahorses cultured at a light intensity of 1000 lx had higher incremental wet weight and standard length than those at 100 lx and 2500 lx. Seahorse growth rate decreased with increasing stocking density (0.25, 0.5, 1 and 1.5 inds/L, respectively) during the 10-week study. Male seahorses grew much faster than females, with incremental wet weights of male and female seahorses of 6.64 ± 1.601 g and 5.87 ± 1.173 g, respectively, in the 0.25 inds/L treatment. The brood pouches of the males emerged earlier, and the ratio between the pouch length and standard length was higher at the higher stocking densities (1 and 1.5 inds/L). The final body weight, weight gain (WG) and specific growth rate (SGR) of the male and female seahorses that were fed 4 times per day were the highest, while those fed 3 times per day had the highest standard length after 10 weeks of culture. The ratio of the length of male brood pouch to standard length was the highest in the low feeding frequency treatment (fed once a day). The incremental wet weight and standard length of sub-adult seahorses differed significantly among the different salinities (35, 33, 31, 29 and 27‰) after 8 weeks of culture ( F 4,60 = 18.950, F 4,60 = 9.225, P < 0.05) with greatest growth at 31–33‰. Results demonstrated that appropriate light intensity, stocking density, feeding frequency and salinity can improve the growth rate of the sub-adult seahorses and affect the development of the brood pouch in male seahorses.

Breeding and juvenile culture of the lined seahorse, Hippocampus erectus Perry, 1810

All seahorse species worldwide have been placed under CITES Appendix II since 2004, because they have been over-exploited for traditional Chinese medicine and aquarium trades. Aquaculture has been recognized as a long-term solution for sustaining the seahorse trade while minimizing wild collection. In this study, we evaluated the breeding and juvenile culture of an important aquarium seahorse species, the lined seahorse Hippocampus erectus, Perry 1810. Pairing, mating and copulation behavior were observed. Gestation time and brood size were 17.33 ± 2.94 days and 272.33 ± 66.45 individuals/brood, respectively. Growth rates differed among juveniles from different broods. Effects of temperature on the growth rates and survivorship of the juveniles during the first two weeks were compared. The highest growth rate and survivorship of the juveniles occurred at 28–29 °C among the temperatures tested (24–33 °C). Growth rate and survivorship of the juveniles during the first 9 weeks at 28 °C were investigated. The final standard length and survivorship of the juveniles were 6.32 ± 0.52 cm and 71.11 ± 10.18%, respectively, and the relationship between the wet weight and the standard length of the juvenile seahorses can be expressed as: W = 0.0034 L 2.5535 ( r 2 = 0.9903, n = 12, P < 0.01). These findings suggest that H. erectus is a good candidate for commercial aquaculture.