Advances in Environmental Science and Energy Planning Effects of first feeding regimes on growth and survival of pipefish (Syngnathus spp.) L. MOLINA-DOMINGUEZ, A. LOZA, M. FERRAN, A. VILAR, and A. SEGADE IU-Ecoaqua University of Las Palmas de Gran Canaria Muelle de Taliarte s/n 35214 Telde (Las Palmas) SPAIN [email protected] Abstract: Syngnathid populations are submitted to uncontrolled exploitation and inadequate management of their natural environment. Thus, culture of these species could contribute to satisfy their exhibition demand on public aquaria while supports the recovery of wild stocks. One of the main goals in modern aquaria is to complete the biological cycles of animals shown in their exhibitions, especially interesting in rare or threatened species showing high visitors’ interest. The present study was conducted to test the effect on growth and survival of different Artemia enrichments used as first feeding for the newborn pipefish (Syngnathus spp.). The four tested diets were: non-enriched Artemia, and three diets using enriched Artemia metanauplii using different products, two based on microalgae, Isochrysis galvana and Tetraselmis suecica, respectively, and the last one enriched on a commercial product, DHA protein SELCO (INVE, Belgium). Survival and growth parameters (size and weight) were studied along the trial, as well as data on water quality (temperature, dissolved oxygen, pH and salinity) were recorded.The results showed excellent survival (98% on average) in all the used diets, however differences on the growth rate has been observed. According to the results, juveniles fed on DHA protein-SELCO enriched Artemia metanauplii showed the highest size and weight at the end of the experiment. Key-Words: First feeding, survival, growth, breeding, aquaria, pipefish. 1 Introduction Some investigations into the international trade in syngnathids revealed a large and growing trade in Pipefish, along with seahorses, are members of the seahorses, pipehorses, and pipefishes for use in family Syngnathidae. These species presents a large traditional medicines, aquarium fishes, and distribution all over the Eastern Atlantic from curiosities [6],[7]. Norway to Senegal and from Namibia to Cape of Good Hope (South Africa); their presence has been The demand for various syngnathid fish has confirmed in Canary Islands [1]. It has been also been met traditionally by the collection of animals cited on Mediterranean coasts as Aegean and Black from the wild but the long term survival of natural seas [2]. Despite literature records, occurrence in the populations is likely to be jeopardised by an Indo-Pacific outside South African waters lacks increase in demand [8]. Nowadays, the conclusive evidence [3]. Knowledge on this family overexploitation of their stocks, it is now widely is generally scarce but has been increasing in recent acknowledged. Besides, species’ limited dispersal years due to their conservation status. Their status ability may make it more vulnerable to extinction has been the focus of increasing concern since the [9] especially if their habitats are fragmented [10]. mid 1990s, both in their own right and as flagship In addition, several of the factors pointed to as species for broader marine conservation issues [4]. sources of endangerment for marine species – e.g., They are a charismatic group of fish that attracts a narrow distribution, vulnerability of its habitat to high level of public support and sympathy [5]. destruction, and rarity – apply to the pipefish. For ISBN: 978-1-61804-280-4 51 Advances in Environmental Science and Energy Planning all these reasons, aquaculture must be considered as eicosapentaenoico (EPA; 20:5n-3) and an alternative to wild collection, especially for some docosahexaenoic acids (DHA; 22:6n-3) and these species of syngnathids [11], [12], [13]. must be supplied in the diet to ensure optimal growth and survival [19]. Because of that, the The presence of pipefish and other nutritional enrichment of live prey organisms before syngnathids in public aquaria is very common. The feeding is a common practice in aquaculture. popularity of these species is related on its look, attractiveness and its unusual reproductive Little is known about the nutritional behaviour, males have a brood pouch found beneath requirements of pipefish. In most species, the the anal fin, where females deposits their eggs and newborn fish are released from paternal pouch at a where are incubated until birth. The public aquaria later stage of development than occurs for other function is not only to provide entertainment and teleosts fish. It has not been established yet if relax to visitors and to increase their knowledge of newborn pipefish have the same requirements as environmental problems. Syngnathids have the other fish larvae. In the other hand, anesthetic potential to act as powerful icons for sustainable methods have generally been used in aquaculture to uses in public aquaria. These institutions can be reduce fish stress and improve handling [20], adopting environmental friendly and sustainable however its use for ornamental species is unusual. procedures, among them it can be stressed the There are scarce references relative of its use in development of technology for the rearing of Syngnathidae family in general and pipefish in ornamental species [14]. This statement is useful for particular. any ornamental specie but it can be stressed the case of the pipefish, focused species in this work because This work is focused in the greater pipefish, these species present natural spawning in aquaria. Syngnathus acus, however some data of Synghathus thyple were also presented. These species are very Pipefish are primary zooplanktivous; small common in public aquaria because the high level of crustaceans are the main food and in terms of public interest due its aspect and behavior. numerical and frequency of occurrence, as copepods, amphipods and crustacean larvae [15]. The main aim of this work is to test the These fish are not locked-in to the consumption of effects on survival and growth of newborn pipefish, specific prey but correlated by the seasonal of different enrichment (differing on n-3 HUFA abundance of different prey [16], [15]. The pipefish contents) of Artemia salina, the most commonly are a small species with a small mouth adapted for used live preys in aquaculture preying small animals using a strong inhalant current to capture them. With such small prey, 2 Material and Methods pipefish must consume large numbers of food organisms [8]. Because these reasons, the provision This study was carried out in the in the Aquarium on abundant and adequate live prey organisms is an Finisterrae in La Coruña (Spain). When pregnant essential tool for breeding these animals in captivity pipefish males were observed at exhibition aquaria, conditions. Artemia salina is one of the most clearly distinguished by the distended brood pouch, commonly used prey in aquaculture, as well as, in it was gently removed and transferred to a 30 l glass public aquaria, due to the existence of standardized aquarium and maintained at 20ºC on a diet base on cost-effective protocols for their mass production. Artemia until the offspring release. Batches released These live prey have been also used in syngnathid from a single male were divided into equal groups at breeding with different degrees of success, a stocking density of 5 pipefish L-1. For S. acus, depending upon animal size and species [17]. three batches were treated in the same way resulting three replicates for each diet. The experiment was Moreover, the success of fish larval rearing non-concurrent as batches were released at different is greatly influenced by first feeding regimes and the times [8]. In the case of S. thyple only one spawning nutritional quality of starter diets [18]. In this sense, episode occurred during the experimental period. the dietary lipids are recognized as one of the most The batch released was equally divided into three important nutritional factors that affect larval groups at a stocking density of 5 pipefish L-1 and growth and survival and in particular highly only T4 was tested. unsaturated fatty acids (HUFA). Numerous studies have shown that marine fish larvae have a dietary Feeding trials were conducted in 12x10 l requirement for arachidonic (ARA; 20:4n-6), polycarbonate containers supplied with flow- ISBN: 978-1-61804-280-4 52 Advances in Environmental Science and Energy Planning through ambient seawater, previously purified using essential oil (Guinama), containing 87% eugenol mechanical filtration and UV light (Philips, with seawater, from a diluted solution 0,5 % (v/v) in 25W/G25T8UV-C, Holland) at a flow rate of 10 96% ethanol (Panreacs, Barcelona, Spain) were used L/hour. Light was provided by fluorescent tubes as anesthetic during handling. Fish was measured (Sera blue sky, 36W, 12000º K, Germany) and the from the tip of the snout to the tip of the tail, dried photoperiod was 14 h light: 10 h dark. Temperature on blotting paper and weighed on an electric balance (ºC) and oxygen level (mg L-1) were measured daily (Mettler Toledo, AG204, Greifensee, Switzerland) using a multiparameter instrument (YSI before being returned to the tank. In each sampling Incorporated, Model 55, USA). Measurements of were controlled 10% fish of each tank, except in the other physical parameters as salinity (ppt, initial and final sampling where all individuals were refractometer, Shibuya, Model S-10, Japan), and pH measured and weighted. (Cyberscan PCD-5500, Eutech, USA), were carried out also daily. Nitrogen compounds were measured Concerning statistical analysis, normality twice a week (Seachem Multitest, USA). Plastic and homogeneity of the variable were tested using meshes were added to the tanks in order to provide Kolmogorov Smirnov and Levene’s test holdfast elements for juveniles. respectively [21]. One way ANOVA [21] was used to determine the significance between data and Four experimental diets were tested by triplicate Student-Newman-Keuls test for comparisons for the greater pipefish (S.