Abstract/Overview A 12-week feeding trial was conducted to evaluate the effects of replacing fishmeal with black soldier fly larvae (BSFL) meal on growth performance and carcass composition of African catfish fingerlings. Five isonitrogenous (40% CP) diets of 0 (Control), 25, 50, 75 and 100% fishmeal with BSFL were used in triplicate. A randomized complete block design was used, and 600 fingerlings (0.46±0.02g) were randomly selected and stocked at a rate of 40 fingerlings in 15 plastic ...
Abstract Chronic stress poses a challenge to aquaculture, with cortisol and glucose traditionally used as stress markers. Recent doubts about the reliability of scale cortisol as a chronic stress determinant have surfaced due to its role in calcium homeostasis. While cortisol affects gene expression in stress responses, its impact on metabolic pathways in cultured Nile tilapia remains understudied. We explored the connection between cortisol signatures of chronic stress in Nile tilapia and t...
Abstract Background. Aquatic insect community structure is dynamic due to threats by anthropogenic activities coupled with changing climatic conditions. The insect’s survival is dependent on the substrate, water quality, and environmental effects. The changes in water quality influence their distribution and abundance and are reflected in spatial and temporal trends. This study sought to document the effects of spatial variation on aquatic insects in Winam Gulf of Lake Victoria, Kenya. Mat...
Abstract Naromoru is a semiarid area in Central Kenya, occurring on the leeward side of Mt. Kenya. Its water sources include a few permanent rivers such as Nairobi River, intermittent streams and a large number of undrainable water reservoirs. Most of the undrainable water resources have been stocked with fish but their utilization for fish rearing has generally remained very low. The purpose of this study was therefore to examine the water quality status of the dams to assess their suitabil...
Abstract/Overview A number of logistic, financial and administrative challenges make it difficult collect adequate and suitable data in order to apply classical fisheries management strategies. Consequently, the more data intensive classical fisheries biological and economic (bio-economic) models do not provide adequate and reliable analytical results for fisheries management. Alternative models are required to deal with the data poor situations in Lake Victoria but also to provide a robu...
Abstract: Fish farmers are a vulnerable group to climate variability and extreme climate events effects as their production heavily relies on precipitation and temperature. However, previous studies on vulnerability of fish farmers to climate variability and extreme events have been done on global, regional and national scales, thus failing to capture the local realities on spatial variability. The current study was carried out to assess the householdlevel vulnerability of fish farmers to cl...
Abstract: This thesis is a study of the occurrence, behaviour, spatial distribution, and temporal distribution of cetaceans in the Greater Dyer Island area, Western Cape, South Africa. Three main methods were used in the study: Analysis of data from a local whale-watching vessel (WWV) (2000 2012), visual land-based theodolite tracking (during four southern right whale seasons (August December) from 2011 2014 and one summer/autumn season in 2013), and passive acoustic monitoring (PAM) using a...
Abstract: Thirty - seven species of cetacean are recorded from southern African waters. Four thousand, five hundred and thirty - seven records of approximately 60 000 cetaceans were analysed to defme distribution patterns of these species, including dedicated sightings (both scientific and commercial), incidental sightings, commercial catches and specimens. Records of dedicated scientific sightings and incidental sightings were analysed by water depth, sea surface temperature and salinity an...
Abstract: No abstract available
Abstract: Killer whales are the oceans’ apex predator and are known to have important effects on ecosystems. At Subantarctic Marion Island, southern Indian Ocean, they have only been studied opportunistically, resulting in limited knowledge of their ecosystem impact here. This dissertation describes the prey and seasonal abundance, estimates the population size and assesses the predatory impact of killer whales on seals and penguins at Marion Island, using dedicated and opportunistic shore...
Abstract: This study was aimed at analyzing beef cattle value chain in Bora and Dugda districts, Oromia Regional State, Ethiopia. The specific objectives of the study were to:- identify major beef cattle value chain actors and their roles in beef cattle value chain in the study areas; Identify the major constraints and opportunities in beef cattle value chain; analyzing the determinants of smallholders farmers' market participation decision and quantity of beef cattle supplied to the market ...
Abstract: Lake Zeway fishery is threatened with problems of overexploitation and consequently unrecovered resources resulting in loss of its potentials due to mismanagement. This study identified the determinants of fishermen’s willingness to pay for fishery management and measured mean fishermen’s willingness to pay for lake Zeway fishery management. A two-stage random sampling techniques was applied to identify sample fishermen’s from Adami Tulu Gido Kombolcha, Zeway Dugda and Dugda ...
Abstract: Agriculture plays vital role in Ethiopian economy. However, despite its importance and potential, the sector has remained at subsistence level. One of the traditional sources of animal protein of the developing world is through livestock rearing. Unfortunately, the livestock production is under increasing pressure from the combined effects of human population growth, shortage of grazing land and desertification. Therefore, it is important to look for a better and cheap, alternative...
In South Africa the green macroalga Ulva armoricana is the main species of macroalgae cultured. The species is currently the largest aquaculture (2884.61 tonnes) product by weight with a corresponding capacity for biogas (CH4) production. We have shown that biotransformation of U. armoricana to Liquefied Petroleum Gas (LPG) is viable and economically feasible as a clean fuel. pH toxicity tests showed that U. armoricana can be used as a health index, under potentially increased CO2 concentrati...
Kenya has a tremendous great potential for growth in the aquaculture sector. To attain the sustainable development goal of zero hunger, the government is needed to encourage fish culture among the rural communities. The study's objective is to investigate the elements that affect the sustainable development of fresh water Aquaculture in Kenya a Vihiga County case. The purpose of the research is to determine how production characteristics and extension affect the long-term sustainability of fr...