Journal of Survey in Fisheries Sciences 7(1) 43-54 2020 Estimation of live food consumption for Hippocampus barbouri and Hippocampus kuda Len Y.W.1,3; Christianus A.1,2*; Worachananant S.3; Muta Harah Z.2; Chong C.M.2 Received: March 2019 Accepted: September 2019 Abstract Seahorse is found worldwide in marine habitats such as the seagrass beds, coral reefs, mangroves and estuaries. Among all the seahorses, Hippocampus barbouri and H. kuda are the most traded species. In recent year, worldwide attention strongly supports the establishment of seahorse aquaculture as to provide an alternative source of seahorse. However, the main bottleneck in succeeding seahorse aquaculture at the culture of early stage, is the diet. The selection of suitable diet will contribute to the success in the larval rearing of seahorse. In this study the consumption of live food by newborn, juvenile and adult seahorse were investigated. H. barbouri and H. kuda commenced feeding at birth. The used of live food, namely the newly hatched Artemia nauplii was able support the growth and survival of newborn and juvenile seahorses in specific tank systems. The results shows an increasing trend, with average numbers of Artemia nauplii consumed increase as the age and size (height) of seahorse. The minimum numbers of nauplii consumed by H. barbouri and H. kuda at 3 day after birth (DAB) with height 14.24±0.14 mm and 10.71±0.13 mm, were 7 and 5 nauplii per feeding respectively. This study showed that Artemia nauplii can be used as live food for newborn H. barbouri to 28 DAB, while for H. kuda from newborn to 42 DAB. At 90 DAB onwards, the used of adult Artemia instead of nauplii is highly recommended for H. barbouri, Downloaded from sifisheriessciences.com at 10:08 +0330 on Friday October 1st 2021 [ DOI: 10.18331/SFS2020.7.1.4 ] Keywords: Hippocampus barbouri, Hippocampus kuda, larval rearing, Artemia 1-Institute of Bioscience, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia. 2- Department of Aquaculture, Faculty of Agriculture, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia. 3-Department of Marine Science, Faculty of Fisheries, Kasetsart University, Bangkok, 10900, Thailand *Corresponding author’s Email: [email protected] 44 Len et al., Estimation of live food consumption for Hippocampus barbouri and Hippocampus kuda Introduction spot on the body, but not as attractive as The genus Hippocampus is categorized H. barbouri. Due its large size, it is under the family Syngnathidae, the often preferred in TCM trading (Job et same as pipefishes, pipehorses and al., 2002). This seahorse normally exist seadragons (Lourie et al., 2004). Unlike in shallow area of coastal bay and most of the fish, they do not have scales lagoons rich with seagrass or floating but instead bone structure that is made weeds. Poor mobility of seahorse made up of little plates and covered by a thin it an easy capture. Its low density layer of skin. Sexual characteristics in existence in the wild has made the seahorses are distinctly different condition even worse (Foster and compared to other fishes, whereby Vincent, 2004). Concerns over the female produces eggs and transferred sudden declines in wild seahorse them to the male for fertilization and populations have led to seahorse incubation (Foster and Vincent, 2004). aquaculture. Establishment of seahorse The decreased numbers of seahorse aquaculture is by far the most suitable along the coastal area show that the method to achieve both sustainable and seahorse populations are greatly conservation goals by providing an affected by over harvesting and habitat alternative source of seahorse hence degradation. The ornamental trade and reducing the dependence on wild stock traditional Chinese medicine (TCM) are (Martin-Smith and Vincent, 2006). two main industry that’s exploit these However problems arise in the effort to seahorses (Foster et al., 2016). establish seahorse culture, mass In order to prevent further mortality at the early stage mainly due exploitation, all seahorse species have to lack of suitable culture technique and been placed under the Convention on diet (Sheng et al., 2006; Planas et al., International Trade in Endangered 2008). Species (CITES) in May 2004. Availability of suitable initial food Countries signing this international for marine fish larvae is critically agreement will not utilize wild important in aquaculture to ensure the seahorses for export purposes (Perry et survival and continuous growth of al., 2010). cultured species. Food value for a Hippocampus barbouri also known particular fish species primarily as Barbours`s seahorse, often appear in affected by the size of food. Fish will Downloaded from sifisheriessciences.com at 10:08 +0330 on Friday October 1st 2021 [ DOI: 10.18331/SFS2020.7.1.4 ] different shades of color like white, take longer time and more energy spent yellowish, brown with dark bands to achieve satiation if fed with smaller across the dark lateral body and striped size food, and this will subsequently snout. The uniqueness in shape has results in poor growth due to made seahorses suitable for aquarium insufficient feeding and energy wastage display. As for Hippocampus kuda, it is (Lim et al., 2003). Hippocampus spp. normally appear in black and brownish like other seahorses are predators, yellow or even orange, often with dark therefore only feed on moving prey like Journal of Survey in Fisheries Sciences 7(1) 2020 45 plankton and small crustaceans in the live food for cultured species at early natural environment. They are slow and stage. In this study, the use of Artemia poor swimmers, often remain stationary as live food for H. barbouri and H. by clinging to substrates with their kuda at different life stages were prehensile tails (Choo and Liew, 2006). investigated. They are without teeth and feeding is through suction motion with their thick Materials and methods snouts and jaws (Lourie et al., 2004). Production of juvenile seahorse Newborn seahorses are unable to take Experiments were conducted at two in food that is larger than the snout different locations for two species of opening. In seahorse aquaculture seahorses. Hippocampus barbouri at feeding becomes the major problem for Hatchery unit, Institute of Bioscience, seahorse hobbyist and researcher due to Universiti Putra Malaysia, Serdang, their complicated feeding behavior, Selangor, Malaysia and H. kuda at Unit with unknown consumption amount, Training, Faculty of Fisheries, Kasetsart prey preferences and nutritional University, Bangkok, Thailand. Mature requirements (Woods, 2002). F2 H. barbouri line which established Initial food for marine fish larvae from 3 pairs of wild broodstock bought normally does not includes commercial from fisherman at Semporna, Sabah in dry feeds due to the immobility of feeds 2013. While mature Hippocampus kuda and digestibility, therefore marine fish broodstock sourced from fisherman at and crustacean hatcheries depend various locations in Thailand, were mainly on cultured or wild zooplankton used to produce juvenile for this study. such as rotifers, copepods and Artemia Broodstock were conditioned in a nauplii (Faulk et al., 2005). As such, laboratory with constant feeding and Artemia became the most convenient optimum water parameters. Pair of live food since it can be hatched from broodstock showing courtship behavior market ready cysts (Sorgeloos, 1980; were then separated and placed in Léger et al., 1986). Upon hatching, the breeding tank. Feeds used were of small sized nauplii is acceptable by Macrobrachium spp. post larvae (PL) most cultured fish larvae and shellfish, caught from nearby freshwater pond, and subsequently gives a better growth Penaeus vannamei PL (supplied by and survival for aquaculture species Asia Aquaculture Sdn Bhd, Malaysia), Downloaded from sifisheriessciences.com at 10:08 +0330 on Friday October 1st 2021 [ DOI: 10.18331/SFS2020.7.1.4 ] (Dhont et al., 2013). In addition, frozen mysid (Hikari, Japan) and adult Artemia at instar II stage can be Artemia (cultured from nauplii stage). enriched to temporarily cater for Upon release, the newborn seahorses nutritional requirements of certain were transferred into a nursing tank. cultured species (Ohs et al., 2013). These have convinced most people Culture system involved in aquaculture specifically in All broodstock tanks for Hippocampus larval rearing, to use Artemia nauplii as barbouri were equipped with 46 Len et al., Estimation of live food consumption for Hippocampus barbouri and Hippocampus kuda Ultraviolet (UV) and hang-on filter biofiltration unit containing bioball. (containing biofiltration materials) for Plastic chains tied to weigh stone were water recirculation. While all used as holdfast for broodstocks. broodstock tanks for Hippocampus Newborn seahorses were removed from kuda were equipped build-in the breeding tank and placed in nursing glass tanks measuring 40x25x30 cm (Fig. 1) equipped with undergravel sand bed and hang-on filter. Figure 1: Seahorse nursing tank, arrows indicate recirculation of water in the tank system. Feed preparation of the seahorses. Chlorella sp. (from Artemia cyst (Bio-Marine, USA) was SATREPS Project in UPM) was use as used throughout this study. Hatching of feed for Artemia throughout the study Artemia was carried out daily to period. provide newly hatched nauplii to the newborn seahorse. Artemia cysts Feeding Experiment for early stage weighing 0.2g was incubated in 2L of juvenile seahorse seawater in a beaker with strong The first experiment was carried out to aeration. Approximately 24 hours later, determine the numbers of Artemia nauplii were released. Harvesting was nauplii consumed by newborn H. carried out by removing the aeration, to barbouri at 3, 7, 14, 21 and 28 DAB. allow the nauplii to congregate at the Beakers of 2L were filled with seawater bottom of the beaker, while the cyst and provided with slow aeration. Downloaded from sifisheriessciences.com at 10:08 +0330 on Friday October 1st 2021 [ DOI: 10.18331/SFS2020.7.1.4 ] shells float at the surface. After 5 Feedings were carried out at 0900 for minutes, nauplii were siphoned from all age groups.