Effect of Variant Manure on Generation Time in Daphnia sp. Herman Hamdani 1* , Asep Sahidin 1,2 , Taufiq Hidayat 3 1 Department of Fisheries, Faculty of Fisheries and Marine Science, Universitas Padjadjaran, Indonesia 2 Laboratory of Aquatic Resources, Faculty of Fisheries and Marine Science, Universitas Padjadjaran, Indonesia 3 PT Mina Maritim Indonesia, Indonesia * Corresponding autor: Hamdani_herman@yahoo.com ABSTRACT The research about generation times of Daphnia sp. was carried out on Mei – June 2017 in Biology Laboratory, FPIK UNPAD. The objective of this research was to analyse the generation time of Daphnia sp. in different manure. The research used experimental method Randomized Completely Block Design (RCBD) with four treatment and three replication. The variant of manure as treatment were chicken manure (A), quail manure (B), cow manure (C), and goat manure (D). The weight for each manure media as many as 2,4 g/l in 1 litre of glass media. The best performance of life table distribution showed from the cow manure, but quail manure treatment give the best of all biological factor, it mean that Daphnias were cultured with quail manure have good performance in biological parameter. Keywords : Daphnia culture, generation times, 1. Introduction Rapid advancement of fisheries sector also give impact for the resources management, technology, and knowledge. The one of the most potent resources is Daphnia sp. as the part of zooplankton. Daphnia plays a central role as an energy transfer between producer and secondary consumer in the food webs of the aquatic ecosystem (Kim. et al, 2017) and also used to be natural feed for aquaculture. Natural feed brings risks for bioaccumulation (Celia et al. 2000) such as pesticide, heavy metals, and their mixtures (Mansour, 2015). The best effort to get the great of natural feed is manipulating the environtment like the native habitat and good nutrition supported (Prastya et al. 2016). Artemia sp. is an example for the best of natural feed in aquaculture. In reality, Artemia sp. has expensive price and difficult to culture particularly for fish farmer from Indonesia. Daphnia sp. is the best natural feed for tropical fry fish and also has potential to be an alternative to subtitute Artemia sp. function as natural feed. The high reproduction rate, the ease of culturing, the accessibility to experimental manipulation, and the potential to applu sophisticated measuring thechniques such as flow cytometry render some ciliate species ideal candidates for ecophysiological laboratory experiment (Weisse, 2006). Daphnia sp. is the potential of natural feed source to develop for aquaculture (Mubarak et al. 2009). Another strengths of culturing Daphnia sp. are sterile assured, free from diseases, also guaranteed quality and continuity because stocking Daphnia sp. into culture media will not make water quality stress (Darmawan 2014). Nutrient for Daphnia sp. culture obteined from manure in media. Decomposition from manure will growth bacteria, and the bacteria will be a feed source for Daphnia sp. (Shigang 1985). Ammonia is the first substance from organic matter decomposition. Ammonia devided into un-ionized ammonia (NH 3 ), and ionized ammonia (NH 4 + ). Ammonia in water will more toxic with pH increase (Xiang. et al, 2010). Generation time in particular, is a life- history or period from the laying of an egg to the time the individual which develops from that egg reaches sexual maturity. Generation time in the single most important determinant of the rate of population growth in species and thus (Gillooly, 2000). Daphnia sp species and another microcrustacean give short of Omni-Akuatika, 14 (2) : 86 – 90 , 2018 ISSN: 1858-3873 print / 2476-9347 online Research Article journal homepage: http://ojs.omniaquatika.net