Artificial Breeding Protocol and Optimal Breeding Environment for ...

International Journal of Fisheries and Aquatic Studies 2014; 1(6): 138-143

ISSN: 2347-5129 IJFAS 2014; 1(6): 138-143 © 2013 IJFAS www.fisheriesjournal.com Received: 03-06-2014 Accepted: 17-06-2014 Paul Sagwe Orina Kenya Marine and Fisheries Research Institute, National Aquaculture Research Development and Training Centre, P.O. Box 451-10230, Sagana, Kenya.

Artificial Breeding Protocol and Optimal Breeding Environment for Labeo victorianus (Boulenger, 1901) Paul Sagwe Orina, Joseph Rasowo, Elijah Gichana, Benard Maranga, Harrison Charo-Karisa Abstract

Joseph Rasowo Department of Biological Sciences, University of Eldoret, P. O. Box1125, Eldoret, Kenya. Elijah Gichana Kenya Marine and Fisheries Research Institute, National Aquaculture Research Development and Training Centre, P.O. Box 451-10230, Sagana, Kenya Benard Maranga Department of Biological Sciences, University of Eldoret, P. O. Box1125, Eldoret, Kenya. Harrison Charo-Karisa State Department of Fisheries, National Aquaculture Research Development and Training Centre-Sagana, P. O. Box 26-10230, Sagana, Kenya.

Correspondence: Paul Sagwe Orina Kenya Marine and Fisheries Research Institute, National Aquaculture Research Development and Training Centre, P.O. Box 45110230, Sagana, Kenya.

Broodstock were collected by use of an electro-fisher from four rivers; Mara, Migori, Nyando and Yala and transported to KMFRI Sangoro hatchery for spawning. They were subjected to a 3 x 2 x 4 factorial design (3 temperatures x 2 ovaprim dosages x 4 populations) with 72 treatments (3 replicates per treatment) in aquaria flow through system. Each replicate in every population were subjected to 22± 1°C, 26± 1°C and a control (no temperature regulation). Two ovaprim dosages (0.2 and 0.5 mlkg-1) administered to female brooders. Latency period significantly (p < 0.05) varied among treatments but remained the same among populations. There was no significant difference (p > 0.05) in latency period between the two ovaprim dosages (0.2 and 0.5 mlKg-1). However, temperature had a significant (p < 0.05) effect on the spawning time, brooders under 26±1 °C responded at 6-8 h, those under 22±1 °C responded at 12-18 h and the controls responded at 16-18 h. Fecundity significantly (p < 0.05) depended on fish size and river source. Mean fertilization and hatching rate were both dependent on temperature with temperature of 26±1 °C being the best performer for all populations. Ovaprim dosage had no effect on ovulation. Larval survival was directly dependent on temperature with 26±1 °C having the highest larval survival (89%), while the control had the least survival (67%) but not significantly different from temperature 22±1 °C (71%). Yolk sac reabsorption was not significantly related to the population source and ovaprim dosage but was directly related to temperature with temperature 26±1 °C having the shortest time (18-24 h) post hatching. Results indicate that ovaprim dosage of 0.2 mlKg-1 and water temperature of 26±1 °C provides the optimal L. victorianus breeding conditions in captivity. Keywords: Labeo victorianus, latency period, ovaprim, temperature, survival

1. Introduction Labeo victorianus locally known as ningu, is as an endemic cyprinid limited to the Lake Victoria basin [1]. It is known to occupy shallow inshore waters and affluent rivers of Lake Victoria spends most of its life span in the lake, but migrates upstream to spawn in flooded grassland beside both permanent and temporary rivers and streams [2, 3, 1, 4, 5, 6, 7]. This predictable migratory habits coupled with the fish’s delicacy among the local communities have over time contributed to a considerable decline of the fish through intensive use of fish traps to harvest gravid ningus migrating up the rivers to breed. Other factors associated with ningu decline include ecosystem degradation, competition and predation by introduced species as well as overfishing resulting in near absence of the fish from the local markets [3, 8, 9]. This therefore leaves captive breeding as the most immediate solution to reducing fishing pressure and ensuring wild population recovery and enhanced aquaculture productivity [10, 11, 12]. However, despite ningu being a local delicacy among western Kenya local communities, culture of warm water food fish has since 1920s been dominated by Nile tilapia (Oreochromis niloticus) and African catfish (Clarius gariepinus). The hatchery and grow-out success of the two species resulting from the mastery of their breeding in captivity coupled with environmental manipulation over time. On the contrary, feeding and water quality management, production of quality seed and initiation of captive restoration programs is a major handicap in introducing a new species into aquaculture [13, 14, 15, 16]. This has resulted to reported cases of collection of ~ 138 ~

International Journal of Fisheries and Aquatic Studies

fingerlings from the wild. Although wild caught juveniles of fish are still utilised in the industry, there are concerns over the sustainability of such practice, and the variable timing and magnitude of natural spawning events, making hatchery production an attractive alternative to support the growing demands of aquaculture [17, 18, 19, 20, 21, 22]. L. victorianus just like C. gariepinus is not known to spawn naturally in captivity. However, unlike C. gariepinus which has had tremendous artificial and semi- artificial propagation techniques developed in captivity since the 70s., L. victorianus propagation techniques are under development with considerable recent success in Kenya and Uganda [23, 24]. The development has resulted not only from the desire to grow the fish by local communities, but more specifically due to the promotion of Fish Farming Enterprise Productivity Program (FFEPP) by the government of Kenya since 2007 under the Economic Stimulus Program (ESP) resulting in increased demand for fingerlings [15, 21, 25].

ovaprim (0.2 and 0.5 ml/kg) of female brooders. Spawning and hatching latency period based on temperature and ovaprim dosage was assessed for all the populations. Relative fecundity and fertilization levels were performed by multiplying the average weight of one egg against the weight lost after spawning. The fertilization rate of eggs was determined after 2 h fertilization by randomly taking a sample of approximately 100 eggs in a petri dish and fertilized eggs having an intact nucleus were counted for calculating fertilization percentage. The duration taken from time of inducement to spawning time (latency period) was recorded. Hatchability rates were recorded by noting the time of spawning and time of the first appearance of hatchlings. 2.1 Data Analysis The quantitative results were examined by analysis of variance (ANOVA 1). When ANOVA indicated significant treatment differences, a Fisher PLSD test was applied to compare means at the p 0.05) between the two ovaprim dosages (0.2 and 0.5 mlKg-1). Temperature had a great effect on the spawning time, brooders under 26±1 °C had a latency period of 6-8 h, those under 22±1 °C (12-18 h) while controls had a latency of 16-18 h. Fecundity significantly (p