Advances in Aquaculture and Fisheries Management

Advances in Aquaculture and Fisheries Management ISSN: 9424-2933 Vol. 5 (10), pp. 001-006, October, 2017. © International Scholars Journals

Full Length Research Paper

Phytoplankton productivity in newly dug fish ponds within Lake Victoria wetlands (Uganda)

Grace Asiyo Ssanyu¹* and Michael Schagerl²

¹Department of Biological Sciences, Kyambogo University, Kampala, Uganda,

²Department of Marine Biology, University of Vienna, Althanstraße 14 A-1090 Vienna, Austria.

Accepted 18 March, 2017

Abstract

The declining Lake Victoria fisheries resource led to a growing recognition of aquaculture as a source of livelihood to riparian communities. Finger ponds speculated to naturally stock fish during flooding and retain them during dry seasons were introduced within the lake’s wetlands. In order to develop a better understanding of these ponds’ dynamics, algal primary productivity was studied in eight newly dug wetland fishponds (8 x 24 m) located in two villages along the northern shores of Lake Victoria (Uganda) before stocking them with fish. Gross primary productivity was low for both sites ranging between 0.00 and 2.63 mg O2 L -1 h-1. The net areal primary productivity of Gaba ponds ranged from -0.34 to 4.66 mg O 2 m-2 d-1 while that of Walukuba ponds ranged from 1.16 to 6.25 mg O2 m-2 d-1. Chlorophyll a mean values were 23.46 ± 12.50 µg L-1 and 75.56 ± 44.35 µg L-1 and mean turbidity ranges were 132.1 – 242.25 and 432.54 - 158.49 NTU for Gaba and Walukuba ponds respectively. Reduced light supply due to the high inorganic turbidity may have been the main limitation for photoautotrophic primary productivity and ponds potential fish yield of 10 - 24 kg ha-1 fish per year.

Key words: phytoplankton, primary productivity, fish ponds, light-limitation, Uganda.

Advances in Aquaculture and Fisheries Management ISSN: 9424-2933 Vol. 5 (8), pp. 001-006, August, 2017. © International Scholars Journals

Full Length Research Paper

Fish fauna diversity of Karamana River, Kerala, India: A study

¹Jancy Rani A.K and ²Jobiraj

¹Research scholar, Bharathiyar University, Coimbatore, Tamil Nadu.
²Assistant Professor, Govt. Collage, Kodanchery, Kozhikkode, Kerala.

Corresponding author. E-mail: [email protected] 

Accepted 11 July, 2017

Abstract

This study on Fish diversity of Karamana river was carried out from October 2015 and September 2016. The fish diversity is correlated with biological and various physio-chemical parameters that regulate the productivity and distribution of different species of fishes. The fish population is abundant and majority of the fishes are exploited for human consumption. For the purpose of the study, attempts were made to collect, classify and identify fish of river Karamana in three zones. The major fish abundance was noticed in the family Cyprinidae; several species of fish belonging to the different order were present. They were Anguliformes, Belonifoemes, Cypriniformes, Cryprinodontiformes, Peraciformes, Siluriformes, Synbranchiformes. The fish species diversity was found decreasing in March and was the highest in October in the year 2015-2016. Among the families of fishes collected Cyprinidae was the most dominant (41.55%), followed by Cichlidae (25.98%),  Mugilidae (14.66%) Bagridae (3.33%), Channidae (3.13%), Siluridae (2.31%), Nandidae (1.79%), Godiidae (1.71%), Clariidae (1.41%), Ambassidae (0.91%), Aploecheilidae (0.80), Heteropneustidae (0.61%), Mastacembelidae (0.61%), Balitoridae (0.60%). The least were observed in Anguillidae (0.30%), Belonidae (0.20%) and Cobitidae  (0.10%). The data shows the rivers are dominated by Cyprinidae with more ornamental fishes than cultivable and food fish. The Cichliddae family that dominates second has three species that are cultivable and food fish. The main reasons behind the decline of species are habitat destruction, introduction of exotic species, pollution and over fishing. Proper conservation methods and prevention of pollution can increase the number of food fish and cultivable fishes in the river. Information about the demography of the important threatened fishes points to the lack of conservation efforts. The result of the present study provides an insight on fish diversity of Karamana river, its proper management and the importance to conserve the fish diversity.

Keywords: Karamana river, fish diversity, exotic species, pollution, conservation, Western Ghats.

Advances in Aquaculture and Fisheries Management ISSN: 9424-2933 Vol. 5 (7), pp. 001-009, July, 2017. © International Scholars Journals

Full Length Research Paper

Catch rate of juveniles Ethamatosa fimbriata, Sardinella maderensis, and Brachydeuterus auritus fishing in Freetown Peninsular

M. Sheriff¹*, K. Kevin¹, T. N. Ndomahina², E. Taylor¹, O. K. M. Badr³, K. J. Boateng¹and R. Sandi²

¹International Centre for HACCP Innovation, Salford Business School University of Salford, Manchester, United Kingdom.

²Institute of Marine Biology and Oceanography, Fourah Bay College, University of Sierra Leone, Freetown, Sierra Leone.

³El Safa Street, El-Seouf, Shamma, El-Falaky, Alexandria, Egypt.

Accepted 13 April, 2017

Abstract

We investigated the incidences of juvenile fishing according to fishing practices in Freetown peninsular. The industrial trawl fishing sector, despite its technology is not fully selective to avoid by-catch of juvenile fish, and artisanal fishing is so less for economic reasons. Ineffective enforcement of fishing regulations is a major cause to the catch of both targeted and non-targeted juvenile fish. We collected data on the quantity of juvenile fish and the daily duration of fishing trips in four landing sites over a two-week period Bernoulli random variables and properties of uniform distribution were used to analyze the data. Catch rates of juveniles Ethamatosa fimbriata, Sardinella maderensis, and Brachydeuterus auritus around the Freetown peninsular were 170.8, 212.4 and 194.60 kg per hour per day, respectively. This rate revealed that the current trend of juvenile fish landings is a threat to the sustainability of fishery capital, revenue, and biodiversity.

Key words: High juvenile, landing, national problem, Sierra Leone, by-catch juvenile.

Advances in Aquaculture and Fisheries Management ISSN: 9424-2933 Vol. 5 (6), pp. 001-014, June, 2017. © International Scholars Journals

Full Length Research Paper

Mathematical modeling of dissolved oxygen in fish ponds

W. J. S. Mwegoha*, M. E. Kaseva and S. M. M. Sabai

School of Environmental Science and Technology, Ardhi University (ARU), P. O. Box 35176, Dar es Salaam, Tanzania.

Accepted 16 March, 2017

Abstract

A mathematical model was developed to predict the effects of wind speed, light, pH, Temperature, dissolved carbon dioxide and chemical oxygen demand (COD) on Dissolved Oxygen (DO) in fish ponds. The effects of organic feeds, aeration and fish activity were added to the model developed by Kayombo et al. for Waste Stabilization Ponds (Ecological Modelling 127(2000): 21 - 31) to reflect the situation in fish ponds. Model calibration and validation was done by use of average DO, pH, temperature, COD, CO₂ and algae biomass data measured from RETCO fish ponds in Dar es Salaam; and light intensity data were adopted from Kayombo et al. (2000). Model results showed a linear relationship between simulated DO and measured DO in fish pond (r² = 0. 87) for model calibration and (r² = 0.88) for model validation. Simulation results also showed a general decrease of DO with time in 13 days by 28 and 38% for first and second batch, respectively. Thus, the model developed in this study could be used to predict the DO dynamics in fish ponds. Based on the model results, successful cultivation of healthy fish may require that retention time for water in the fish pond be 10 days.

Key words: Calibration, light, pH, substrate, temperature, validation.