Comparative anatomy of two Artocarpus species was carried out to identify and describe anatomical characters in search of distinctive characters that could possibly be used to delimit the two taxa. Transverse, tangent...Comparative anatomy of two Artocarpus species was carried out to identify and describe anatomical characters in search of distinctive characters that could possibly be used to delimit the two taxa. Transverse, tangential and radial longitudinal sections and macerated samples of the stem and root wood were prepared onto microscopic slides. Epidermal peels and cleared leaves of the two species were made. Characteristic similarity disparity in the tissues arrangement as well as cell inclusions were noted for description and delimitation. The two Artocarpus species studied had essentially the same an- atomical features; however, there were characters that seem to be taxon specific. The study revealed that at the transverse plane of the root, A. communis （J. R. ＆ G. Forster） have predominantly solitary vessel, whereas pore multiple was pre- dominant in A. altilis （Parkinson） Fosberg. Tyloses in vessels of the root were more frequent in A. communis than in A. altilis. In the cleared leaves, venation pattem also revealed some differences in the two species. The veins ofA. communis were more or less straight and that ofA. altilis were undulating especially in the secondary veins. Prismatic crystals were found in the cortex of the petiole in A. communis but not in A. altilis. Similarly, tannins were found in the root bark of A. communis but not in A. altilis. Trichomes and scales were more abundant in A. communis than in A. altilis. In the transverse section of the leaves, abaxial and adaxial epidermis were uniseriate in A. cornmunis but only the abaxial epidermis was uniseriate in A. altilis, the adaxial epidermis was made up of 2 to 3 layers of cells. The epidermal cells in A. communis were predominantly short cylindrical shaped cells but were not so in A. altilis.展开更多
This study assessed the fish production, culture facilities, operations, water resource management and profitability of fish farming in Katsina State, Nigeria, with a view of understanding the status of aquaculture de...This study assessed the fish production, culture facilities, operations, water resource management and profitability of fish farming in Katsina State, Nigeria, with a view of understanding the status of aquaculture development in Katsina State. Data were collected using structured questionnaire administered to 35 out of the active 42 farms in Katsina State at the period and the data obtained were analyzed using descriptive statistics and linear regression. Among the respondents, 37.1% used concrete tank alone and another 37.2% used concrete tank with other types of culture facilities, 57.1% practised mono-culture techniques and 77.1% used stagnant renewal system as culture system. Management of water quality was done by majority(82.9%) with mere visual evaluation, while 68.6% did not use any forms of water treatment. Most of the farms(80%) depended on imported feed for feeding their fish and gross profits of ■7.29±1.81 and ■157.83±118.08 were obtained on fingerlings and adult fish, respectively. The tested explanatory variables were responsible for 45.4% change in profitability and profitability was found to be dependent on feeding cost(t=–3.38 and p=0.002) and size of fish at harvest(t=2.70 and p=0.011). The research findings established that fish farming in Katsina State was under developed.展开更多
The intensification of aquaculture has emerged as a viable alternative for increasing aquaculture production due to competition that arose from the use of natural resources,such as land and water,by other production a...The intensification of aquaculture has emerged as a viable alternative for increasing aquaculture production due to competition that arose from the use of natural resources,such as land and water,by other production and developmental sectors.However,intensification demands increased inputs,such as fish and feed per unit culture area and,therefore,increased waste generation from the aquaculture production systems.The impact of waste products from aquaculture has increased public concern and threatens the sustainability of aquaculture practices.The need for increasing the production of aquaculture products cannot be overemphasized and,therefore,there is a need to develop culture systems that will increase fish production with efficient waste management in order to limit environmental degradation resulting from aquaculture wastes and ensure its sustainability.This paper reviewed various aspects of waste production from aquaculture,their sources,components,and methods of management,in different culture systems,primarily discussing waste production from feed,chemicals,and pathogens.We aimed to establish the sources of wastes,their contents,and potential harms to both the fish culture and the environment.Suggestions for managing wastes in different culture systems were made to ensure an improved and sustainable aquaculture production.展开更多
文摘Comparative anatomy of two Artocarpus species was carried out to identify and describe anatomical characters in search of distinctive characters that could possibly be used to delimit the two taxa. Transverse, tangential and radial longitudinal sections and macerated samples of the stem and root wood were prepared onto microscopic slides. Epidermal peels and cleared leaves of the two species were made. Characteristic similarity disparity in the tissues arrangement as well as cell inclusions were noted for description and delimitation. The two Artocarpus species studied had essentially the same an- atomical features; however, there were characters that seem to be taxon specific. The study revealed that at the transverse plane of the root, A. communis （J. R. ＆ G. Forster） have predominantly solitary vessel, whereas pore multiple was pre- dominant in A. altilis （Parkinson） Fosberg. Tyloses in vessels of the root were more frequent in A. communis than in A. altilis. In the cleared leaves, venation pattem also revealed some differences in the two species. The veins ofA. communis were more or less straight and that ofA. altilis were undulating especially in the secondary veins. Prismatic crystals were found in the cortex of the petiole in A. communis but not in A. altilis. Similarly, tannins were found in the root bark of A. communis but not in A. altilis. Trichomes and scales were more abundant in A. communis than in A. altilis. In the transverse section of the leaves, abaxial and adaxial epidermis were uniseriate in A. cornmunis but only the abaxial epidermis was uniseriate in A. altilis, the adaxial epidermis was made up of 2 to 3 layers of cells. The epidermal cells in A. communis were predominantly short cylindrical shaped cells but were not so in A. altilis.
文摘This study assessed the fish production, culture facilities, operations, water resource management and profitability of fish farming in Katsina State, Nigeria, with a view of understanding the status of aquaculture development in Katsina State. Data were collected using structured questionnaire administered to 35 out of the active 42 farms in Katsina State at the period and the data obtained were analyzed using descriptive statistics and linear regression. Among the respondents, 37.1% used concrete tank alone and another 37.2% used concrete tank with other types of culture facilities, 57.1% practised mono-culture techniques and 77.1% used stagnant renewal system as culture system. Management of water quality was done by majority(82.9%) with mere visual evaluation, while 68.6% did not use any forms of water treatment. Most of the farms(80%) depended on imported feed for feeding their fish and gross profits of ■7.29±1.81 and ■157.83±118.08 were obtained on fingerlings and adult fish, respectively. The tested explanatory variables were responsible for 45.4% change in profitability and profitability was found to be dependent on feeding cost(t=–3.38 and p=0.002) and size of fish at harvest(t=2.70 and p=0.011). The research findings established that fish farming in Katsina State was under developed.
文摘The intensification of aquaculture has emerged as a viable alternative for increasing aquaculture production due to competition that arose from the use of natural resources,such as land and water,by other production and developmental sectors.However,intensification demands increased inputs,such as fish and feed per unit culture area and,therefore,increased waste generation from the aquaculture production systems.The impact of waste products from aquaculture has increased public concern and threatens the sustainability of aquaculture practices.The need for increasing the production of aquaculture products cannot be overemphasized and,therefore,there is a need to develop culture systems that will increase fish production with efficient waste management in order to limit environmental degradation resulting from aquaculture wastes and ensure its sustainability.This paper reviewed various aspects of waste production from aquaculture,their sources,components,and methods of management,in different culture systems,primarily discussing waste production from feed,chemicals,and pathogens.We aimed to establish the sources of wastes,their contents,and potential harms to both the fish culture and the environment.Suggestions for managing wastes in different culture systems were made to ensure an improved and sustainable aquaculture production.
