Evaluation of Baited Remote Underwater Video Systems (BRUVS) for monitoring fish communities in Lake Malawi/Niassa
- Authors: Van Wyk, Angus
- Date: 2020
- Subjects: Underwater videography -- Malawi , Chambo -- Malawi -- Monitoring , Fishes -- Malawi -- Monitoring , Oreochromis lidole -- Malawi -- Monitoring
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/145546 , vital:38448
- Description: Baited Remote Underwater Video systems (BRUVS) have become a well-established in-situ monitoring technique in clearwater aquatic ecosystems. The relatively low cost, nondestructive and non-extractive nature of this technique permits BRUVS to be employed in a wide range of habitats. To date, the vast majority of studies using BRUVS technology have been conducted in marine habitats. Subsequently, BRUVS applications in freshwater habitats are scant, and techniques are not well developed. The primary objective of this thesis was to address this knowledge gap and develop standard operating procedures for BRUVS employment in Lake Malawi/Niassa and explore the potential of BRUVS as a monitoring tool for fish communities in the African Great Lakes. Eight easily identifiable species groups, representative of Lake Malawi/Niassa inshore fish communities, were used to develop the technique. The optimal BRUVS deployment time to obtain 95 % species accumulation was achieved in a 15-minute recording period. Power analysis, using a pre-determined 80 % power, a confidence interval of 95 % and a significance level of < 0.05 was used to determine annual sampling effort requirements for each species group. The power analysis was performed to detect a 10 % change in abundance over a hypothetical 10-year monitoring scenario. In areas where fish abundance was lower, the sampling effort required to monitor key fisheries species was significantly higher. For example, Chambo, the local Oreochromis (Nyasalapia) species flock, required an annual sampling effort of 120 deployments in Malawi compared to 56 in Mozambique ( < 0.05). Chambo had a higher detection probability in areas of lesser fishing pressure and were found in higher abundances in deeper, less accessible habitats. Deep-water (> 20 m) and rocky habitats were most important in explaining Chambo abundance and detection probability. The size-structure of Chambo in Lake Malawi/Niassa reflects size-specific depth and habitat migrations. Larger Chambo were observed aggregating in waters deeper than 20 m and a broader size range of individuals were observed utilising structured habitat. The effects of fishing are apparent in the size-structure of Chambo in the areas sampled. In study areas exposed to greater levels of fishing pressure – such as Malawi, the BRUVS detected significantly fewer individuals within sexually mature size classes, and the average size was smaller than in areas with less exploitation.
- Full Text:
- Authors: Van Wyk, Angus
- Date: 2020
- Subjects: Underwater videography -- Malawi , Chambo -- Malawi -- Monitoring , Fishes -- Malawi -- Monitoring , Oreochromis lidole -- Malawi -- Monitoring
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/145546 , vital:38448
- Description: Baited Remote Underwater Video systems (BRUVS) have become a well-established in-situ monitoring technique in clearwater aquatic ecosystems. The relatively low cost, nondestructive and non-extractive nature of this technique permits BRUVS to be employed in a wide range of habitats. To date, the vast majority of studies using BRUVS technology have been conducted in marine habitats. Subsequently, BRUVS applications in freshwater habitats are scant, and techniques are not well developed. The primary objective of this thesis was to address this knowledge gap and develop standard operating procedures for BRUVS employment in Lake Malawi/Niassa and explore the potential of BRUVS as a monitoring tool for fish communities in the African Great Lakes. Eight easily identifiable species groups, representative of Lake Malawi/Niassa inshore fish communities, were used to develop the technique. The optimal BRUVS deployment time to obtain 95 % species accumulation was achieved in a 15-minute recording period. Power analysis, using a pre-determined 80 % power, a confidence interval of 95 % and a significance level of < 0.05 was used to determine annual sampling effort requirements for each species group. The power analysis was performed to detect a 10 % change in abundance over a hypothetical 10-year monitoring scenario. In areas where fish abundance was lower, the sampling effort required to monitor key fisheries species was significantly higher. For example, Chambo, the local Oreochromis (Nyasalapia) species flock, required an annual sampling effort of 120 deployments in Malawi compared to 56 in Mozambique ( < 0.05). Chambo had a higher detection probability in areas of lesser fishing pressure and were found in higher abundances in deeper, less accessible habitats. Deep-water (> 20 m) and rocky habitats were most important in explaining Chambo abundance and detection probability. The size-structure of Chambo in Lake Malawi/Niassa reflects size-specific depth and habitat migrations. Larger Chambo were observed aggregating in waters deeper than 20 m and a broader size range of individuals were observed utilising structured habitat. The effects of fishing are apparent in the size-structure of Chambo in the areas sampled. In study areas exposed to greater levels of fishing pressure – such as Malawi, the BRUVS detected significantly fewer individuals within sexually mature size classes, and the average size was smaller than in areas with less exploitation.
- Full Text:
Exploring working with Grade 6 Elementary Agricultural Science teachers on how to integrate local knowledge in food preservation
- Authors: Sabina, Hashondili
- Date: 2020
- Subjects: Agriculture -- Study and teaching (Elementary) -- Namibia , Food -- Preservation -- Study and teaching (Elementary) -- Namibia , Education, Elementary -- Namibia , Ethnoscience -- Study and teaching (Elementary) -- Namibia
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/148093 , vital:38709
- Description: Many scholars have reported that science teachers are grappling with linking science to learners’ everyday life experiences and Namibian science teachers are no exception. As a result, learners are finding that scientific concepts often remain decontextualised and abstract. In light of this, the Namibian National Curriculum indicates that teaching and learning should start with the knowledge and experiences of learners from home. It also encourages teachers to integrate local knowledge into their science lessons but does not give proper guidelines on how science teachers should go about enacting this. This tension between curriculum formulation and implementation triggered my interest to carry out an interventionist research study aimed at exploring working with Grade 6 Elementary Agricultural Science teachers on how to integrate local knowledge on food preservation in particular. This study is underpinned by an interpretive paradigm, within which a qualitative case study was employed. It was conducted with three Grade 6 Elementary Agricultural Science teachers from three different schools in the Oshana region of Namibia. I used semi-structured interviews, document analysis, workshop discussions, participatory observation and reflections to gather data. Vygotsky’s socio-cultural theory together with Shulman’s pedagogical content knowledge theories was used as lenses to analyse my data. The findings of the study revealed that the sample teachers understood what indigenous knowledge is and its benefits but struggled to integrate it in their lessons. The findings of the study further revealed that the presentations by the expert community members enabled these teachers to identify possible science topics that they could teach, using some of the traditional practices such as food preservation. The study thus recommends that teachers need to be supported on how to integrate local knowledge or indigenous knowledge in their classrooms. Teachers should therefore be involved in professional learning communities that will help them share their difficulties they encounter during their teaching practices and to collaboratively come up with strategies to overcome such difficulties. Community members who are custodians of the cultural heritage should be invited to share their indigenous knowledge with science teachers so that they can link it from community members to classroom science.
- Full Text:
- Authors: Sabina, Hashondili
- Date: 2020
- Subjects: Agriculture -- Study and teaching (Elementary) -- Namibia , Food -- Preservation -- Study and teaching (Elementary) -- Namibia , Education, Elementary -- Namibia , Ethnoscience -- Study and teaching (Elementary) -- Namibia
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/148093 , vital:38709
- Description: Many scholars have reported that science teachers are grappling with linking science to learners’ everyday life experiences and Namibian science teachers are no exception. As a result, learners are finding that scientific concepts often remain decontextualised and abstract. In light of this, the Namibian National Curriculum indicates that teaching and learning should start with the knowledge and experiences of learners from home. It also encourages teachers to integrate local knowledge into their science lessons but does not give proper guidelines on how science teachers should go about enacting this. This tension between curriculum formulation and implementation triggered my interest to carry out an interventionist research study aimed at exploring working with Grade 6 Elementary Agricultural Science teachers on how to integrate local knowledge on food preservation in particular. This study is underpinned by an interpretive paradigm, within which a qualitative case study was employed. It was conducted with three Grade 6 Elementary Agricultural Science teachers from three different schools in the Oshana region of Namibia. I used semi-structured interviews, document analysis, workshop discussions, participatory observation and reflections to gather data. Vygotsky’s socio-cultural theory together with Shulman’s pedagogical content knowledge theories was used as lenses to analyse my data. The findings of the study revealed that the sample teachers understood what indigenous knowledge is and its benefits but struggled to integrate it in their lessons. The findings of the study further revealed that the presentations by the expert community members enabled these teachers to identify possible science topics that they could teach, using some of the traditional practices such as food preservation. The study thus recommends that teachers need to be supported on how to integrate local knowledge or indigenous knowledge in their classrooms. Teachers should therefore be involved in professional learning communities that will help them share their difficulties they encounter during their teaching practices and to collaboratively come up with strategies to overcome such difficulties. Community members who are custodians of the cultural heritage should be invited to share their indigenous knowledge with science teachers so that they can link it from community members to classroom science.
- Full Text:
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