826 research outputs found
Trawling operations on Lake Victoria
The programme of work in connection with investigations into the feasibility of operating a fishery for Haplochromis has progressed, albeit with interruptions, throughout the year. An account is given in Appendix A of the boat and gear developments which have been stimulated by this survey. With conversion of the Darter to a stern trawler, fishing operations have been speeded up and a total of 85.5 trawling hours has now been completed. A summary of the catch data is set-out-in Table G1 and some comments on the distribution of species is given
The establishment of a commercial fishery for Haplochromis in the Uganda waters of Lake Victoria, Part III 1968
In a previous report (Gee and Gilbert 1968) an attempt was made to
estimate stock densities in the Entebbe area ,of Lake Victoria based on
catch figures obtained in EAFFRO No.1 trawl fitted with a 1" codend
and towed at an estimated1.7.knots (probably an underestimate). The
results were rather discouraging in that the figures obtained for stock
densities were definitely very low. It was felt that the major weakness
of the operations was the trawl net but as it was the only net available
and neither of the authors were expert on the design and construction
of more suitable nets, this particular net had to be used
Notes on the genus Xenoclarias (Greenwood)
One specimen of a small clariid hitherto unknown in Lake Victoria was
collected by MICHAEL GRAHAM in about 15 metres of water at the
western end of the Kavirondo Gulf and described by NORMAN (1928) as
Clarias eupogon. In the late 1950's three further specimens were trawled by
EAFFRO in 37 metres of water off the south west tip of Ukerewe Island.
In a study of this material GREENWOOD (1958) found that "the suprabranchial
respiratory organs were virtually absent and the suprabranchial
chamber almost non-existant". As this condition is found in no other adults of the three subgenera of Clarias, GREENWOOD (op. cit.) used it as the
definitive character for a new genus Xenoclarias and referred NORMAN's
Clarias eupngnn to the same genus. The three specimen and on the basis
of these differences were referred to a new species Xenoclarias holobranchus
(GREENWOOD)
The establishment of a commercial fishery for Haplochromis in the Uganda waters of Lake Victoria
Lake Victoria, straddling the Equator, is the second largest lake in the world, with a surface area of approximately 26,000 square miles (41,500 square kilometers) and a maximum depth of about 300 feet. Uganda possesses most of the north end of the lake which consists of a long, indented coastline and a chain of offshore islands on the edge of a 'continental shelf' separating relatively shallow sheltered inshore waters from the deeper open waters of the lake.
At the present time the lake is harvested mainly by a native gill net fishery confined almost entirely to the shallow sheltered inshore waters. The annual production of all species from Uganda waters is in the region of 24,000 tons per annum, and Tilapia(Cichlidae)is commercially the most important genus. Haplochromis, a close relative of Tilapia, but generally much smaller, contributes only a small amount to this annual production; see Table 1, although they are probably the most abundant group of fish present in the lake.
Through international aid programmes Uganda has been offered a canning plant and it is thought that Haplochromis is the most suitable type of fish to be utilized by such a plant. The Uganda Fisheries Department are conducting research into processing techniques and marketing and the East African Freshwater Fisheries Research Organization was asked to conduct a survey of the Haplochromis stocks of the lake with a view to estimating the ability or otherwise of these stocks to support a commercial canning industry
Fishing gear development 1965-67
The commercial fisheries of lake Victoria are based principally on a number of species of tilapia althougy considerable tonnages of other genera are landed,namely clarias Bagrud,photopteru
A comparison of certain aspects of the biology of Lates niloticus (Linne) in some East African lakes
Lates niloticus nile perch occurs naturally in only two East African lakes L. Albert and L. Rudolf but Foss Record indicate a wider East African distribution in the past fossils of the genus Lates are found in the Miocene beds of Lake Victoria basin
A note on length frequency and "species group" composition of Haplochromis populations in lake Victoria
During the preliminary part of a survey on Haplochromis in a small area of Lake Victoria off Entebbe some interesting information was collected on the composition of the Haplochromis populations. Because of the complex nature of the taxonomy it is very difficult to divide the genus Haplochromis into all its species when working in the field. Certain broad types however can usually be recognized and the genus has been classified into eighteen "species-groups" comprising eight groups of predators and ten groups of non-predators
A discourse analysis of trainee teacher identity in online discussion forums
Teacher education involves an identity transformation for trainees from being a student to being a teacher. This discourse analysis examined the online discussion board communications of a cohort of trainee teachers to better understand the situated identities of the trainees and how they were presented online. Their discussion board posts were the primary method of communication during placement periods and, as such, provided insight into how the trainees situated their identities in terms of being a student or being a teacher. During the analysis, the community boundaries, language and culture were explored along with the tutor's power and role in the identity transformation process. This involved looking at the lexis used by the students, the use of pronouns to refer to themselves and others such as teachers and pupils, the types of messages allowed in the community and the effect of the tutor's messages on their communication. The research found that the trainees felt comfortable with teaching but did not feel like teachers during the course. Tutors and school teachers need to develop an awareness of the dual nature of trainees' identities and help promote the transition from student to teacher. In the beginning of the course, trainees should be familiarised with teacher vocabulary and practical concepts in addition to pedagogical theory. Towards the end of the course, trainee identity as teachers could be promoted through the use of authentic assessments that mirror real teacher tasks and requirements
Experimental trawling operations on Lake Victoria
A programme has been started to investigate the feasibility of operating a trawl fishery for Haplochromis in connection with development of a proposed cannery by the Ugandan government Because of lack of gear much time has been spent on the development of boats and nets for this type of fishing
Tagging experiments on aquaria kept fish utilising floy nylon tags
Whilst discussing a future tagging programme for a number of fish
species of commercial importance in Lake Victoria, Prof. K. Lagler, at
that time Co-ordinator of African Lake Projects, FAD, suggested that for
ease and speed of operation the tags and tagging equipment described by
DELL (1968) should be used. He very kindly provided the equipment and
a number of tags of various types
- …