Research Repository :: Browsing by Author "Gaspare, Lydia"

Browsing by Author "Gaspare, Lydia"

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Complementarity of fishers' traditional ecological knowledge and conventional science: Contributions to the management of groupers (Epinephelinae) fisheries around Mafia Island, Tanzania
(Ocean & Coastal Management, 2015) Gaspare, Lydia; Bryceson, Ian; Kulindwa, Kassim
Traditional ecological knowledge (TEK) is increasingly advocated as a complementary source of information that can potentially be integrated into mainstream science, particularly to help improve fisheries management. However, less attention has been paid to identifying specific areas where the TEK of fishers may confirm or contradict conventional scientific knowledge (CSK); or where TEK may provide new insights for fisheries systems characterized by multi-species and multi-gear usage. We conducted a qualitative exploration of TEK of grouper fishing patterns and compared the findings with an analysis of catch data in order to elucidate the extent of fishing pressure on groupers. We further compared TEK of the ecology and biology of groupers with published CSK to understand the complementarity between the two domains. Data collection methods included structured open-ended questionnaire, semi-structured interviews with key informants, focus group discussions, personal observations and a literature review. Results indicate that TEK complements CSK in terms of catch assessment and the ecology of groupers. TEK provides additional information on fishing gear, specific grouper species caught, habitat use and feeding habits; however, TEK contradicts CSK regarding spawning aggregation behavior. TEK offers new knowledge on environmental threats facing groupers, but fishers lack knowledge on reproductive modes and life history traits (i.e. hermaphroditism and spawning season) of groupers. We conclude that, in a conducive democratic setting based upon mutual respect and trust, TEK can complement conventional science and help to make more informed management decisions for sustainable fishing.
Effectiveness of Marine Protected Areas on fisheries management: Fishers’ opinions in Mafia Island Marine Park, Tanzania
(2016) Gaspare, Lydia
How fishers perceive the outcomes of Marine Protected Areas (MPAs) is fundamental in evaluating the effectiveness of management practices. This study examined the perceptions of fishers on the outcomes of the multi-use Mafia Island Marine Park (MIMP) including no-take zones. The results of structured open-ended interviews with fishers randomly selected from two communities indicate that perceptions are influenced by area of residence, age and fishing gear in use. Fishers were positive about coastal habitat conditions and the elimination of dynamite, poison and beach seine fishing; and they showed a high level of understanding about MIMP regulations. Perceptions about the effects of the MPA on fishers’ own activities, fisheries in general, and the violation of MPA regulations differed with age, gear used and among fishers from the two villages. Respondents who reported being affected by the MIMP were more likely to be those from the community with high reliance on fisheries resources, young fishers, and those using nets and motorized boats. Perceptions about fish catch trends, involvement in planning, enforcement of regulations, and level of conflict did not differ among communities and gear users, but deviated negatively from MIMP goals. Thus, efforts focusing on improving access to sustainable income sources, promoting sustainable fishing gear and developing legal frameworks that support local knowledge and practices may enhance the effectiveness of fisheries management.
Linking ecological and social elements to sustain coral reef fisheries: A case of groupers [Epinephelidae] in Mafia Island, Tanzania
(Norwegian University of Life Sciences (NMBU), 2016-01-15) Gaspare, Lydia
The study of the dynamic nature of interactions within and between social and ecological aspects of reef fisheries is increasing, in order to promote understanding and to mitigate complex changes from global pressure and local threats that undermine sustainable coastal fisheries. In Tanzania, a trial fisheries policy allowing the export of grouper/rock cod, among other fishes, was endorsed in the year 2002. The policy goals were to improve the livelihoods of coastal communities and increase fish product exports. However, studies of the sustainability of commercially targeted fish species in Tanzania are inadequate; no information is available on the ecology and biology of groupers in Tanzanian marine waters that would ensure the sustainability of the fishery. There is a paucity of empirical evidence on impacts of management practices on ecological and social aspects of grouper fisheries. In particular, there is little documentation on the perceptions of small-scale fishers of changes related to Marine Protected Areas (MPAs) as a fisheries management tool. This study investigates linkages between ecology and social elements for sustainability of targeted finfish Epinephelinae (groupers) fisheries in Mafia Island, Tanzania. In particular, this study draws on insights from different knowledge sources to investigate ecological trends of groupers in a Marine Protected Area (MPA), and the biological traits of frequently caught grouper species. The aim is to gain scientific evidence to support sustainable grouper harvesting. Groupers are ecologically important as top-level predators and play a major role in structuring coral reef ecosystems. Being highly priced fish, groupers are heavily exploited for commercial purposes and for local consumption worldwide, hence they are susceptible to overfishing. This vulnerability to overfishing is exacerbated by the life history characteristics of groupers, such as longevity, late maturation and spawning aggregation behaviour. Using histological analysis, the sexual maturity of Epinephelus malabaricus was examined and the relationship between fish size, gear used, and depth of capture was evaluated. Underwater visual census (UVC) results were used to assess changes in ecological traits (body size, biomass and abundance) of groupers with reference to the establishment of the Mafia Island Marine Park (MIMP), and results were compared with fishers’ perceptions. Semi-structured interviews, key informants interviews, focus group discussions, direct observation and informal discussions were used to generate information from fishers’ knowledge and perceptions about the ecology and biology of groupers and management outcomes. Factors influencing fishers’ perceptions of MPA input and outcomes were also documented. Analysis of E. malabaricus specimens, a large grouper species frequently caught by small-scale fishers, showed that all specimens above 90 cm in size were male. Low numbers of large groupers were landed, mostly during the northeast monsoon, a period coinciding with the spawning season (September to February). Interviews with fishers and observations made indicated no sign that small-scale fishers were targeting spawning aggregation areas. Fishers had mixed perceptions concerning changes in size of groupers in the MPA; their perceptions were inconsistent with results from the UVCs which show no changes in size. Perceptions related to changes in abundance of groupers were consistent with data from the UVCs, both indicating a decrease. This observation encourages reconciling information from resource users with conventional scientific data to support effective management. A decrease in abundance of groupers in both no-take zones (NTZs) and specified-use zones (SUZs) was observed. This difference could be explained, among other reasons, as a detrimental effect of fishing. The study also found that fishers’ ecological knowledge and conventional scientific knowledge (CSK) complement one another. Fishers provided information on the dynamics and patterns of grouper utilization in Mafia, habitat preferences, and feeding habits. This information coincides with data from conventional knowledge. Fishers also provided information which is new to CSK, including fishing locations and environmental threats facing groupers in the wild. An area where fishers’ knowledge and CSK did not coincide relates to spawning aggregations. The disagreement may be because both fishers and scientists have limited knowledge of deeper areas of Mafia where groupers are likely to spawn. Besides, fishers lack knowledge of spawning seasons and sex differentiation of groupers. The findings suggest that further collaborative research between fishers and scientists would enhance mutual learning. Fishers’ area of residence and fishing gear operated were found to influence their perceptions of MPA outcomes. Juani fishers felt more impacted by the MIMP than those from Kiegeani, due to the restriction of pull-net fishing which is an important type of gear for Juani fishers. Fishers’ involvement in MPA planning and implementation increased the likelihood of perceiving positive effects of the MPA on fishers’ own fishing activities. However, their involvement in enforcement and local level awareness of MPA regulations did not enhance acceptance of the MPA in the two communities assessed. Lack of access and user rights to productive fishing grounds and gear restrictions are factors responsible for the ongoing conflict between the MIMP and fishers. The results of the study indicate that linking ecological and social aspects of commercially targeted fish resources would contribute to the successful implementation of the ecosystem approach to fisheries at local level. The study shows that reconciling information from different sources enhances the sustainable utilization of fisheries resources. The most important contributions of this thesis include the evidence about size at first maturity of E. malabaricus, the complementarity of fishers’ ecological knowledge and CSK on the ecology and biology of groupers, and the value of fishers’ perceptions on the outcomes of changes in management practices. The study recommends that integration of fishers’ knowledge and conventional knowledge would improve the participation of local communities in the management of reef fisheries resources. The sharing of information and understanding different viewpoints of fishers and western trained managers and scientists, would result in a common forum for discussing problems related to fisheries and the management of MPAs.
Polycyclic Aromatic Hydrocarbon (PAH) Contamination of Surface Sediments and Oysters from the Inter-Tidal Areas of Dar es Salaam, Tanzania
(Elsevier, 2009) Gaspare, Lydia; Machiwa, John F.; Mdachi, S. J. M.; Streck, Georg; Brack, Werner
Surface sediment and oyster samples from the inter-tidal areas of Dar es Salaam were analyzed for 23 polycyclic aromatic hydrocarbons (PAHs) including the 16 compounds prioritized by US-EPA using GC/ MS. The total concentration of PAHs in the sediment ranged from 78 to 25,000 ng/g dry weight, while oyster concentrations ranged from 170 to 650 ng/g dry weight. Hazards due to sediment contamination were assessed using Equilibrium Partitioning Sediment Benchmarks and Threshold Effect Levels. Diagnostic indices and principle component analysis were used to identify possible sources. Interestingly, no correlation between sediment and oyster concentrations at the same sites was found. This is supported by completely different contamination patterns, suggesting different sources for both matrices. Hazard assessment revealed possible effects at six out of eight sites on the benthic communities and oyster populations. The contribution of PAH intake via oyster consumption to carcinogenic risks in humans seems to be low.
Polycyclic aromatic hydrocarbon (PAH) contamination of surface sediments and oysters from the inter-tidal areas of Dar es Salaam, Tanzania
(Environmental Pollution, 2009) Gaspare, Lydia; Machiwa, John; Mdachi, Stevene J.M; Streck, Georg; Brack, Werner
Surface sediment and oyster samples from the inter-tidal areas of Dar es Salaam were analyzed for 23 polycyclic aromatic hydrocarbons (PAHs) including the 16 compounds prioritized by US-EPA using GC/MS. The total concentration of PAHs in the sediment ranged from 78 to 25,000 ng/g dry weight, while oyster concentrations ranged from 170 to 650 ng/g dry weight. Hazards due to sediment contamination were assessed using Equilibrium Partitioning Sediment Benchmarks and Threshold Effect Levels. Diagnostic indices and principle component analysis were used to identify possible sources. Interestingly, no correlation between sediment and oyster concentrations at the same sites was found. This is supported by completely different contamination patterns, suggesting different sources for both matrices. Hazard assessment revealed possible effects at six out of eight sites on the benthic communities and oyster populations. The contribution of PAH intake via oyster consumption to carcinogenic risks in humans seems to be low.
Reproductive Biology and Fishery-Related Characteristics of the Malabar Grouper (Epinephelus malabaricus) Caught in the Coastal Waters of Mafia Island, Tanzania
(Journal of Marine Biology, 2013) Gaspare, Lydia; Bryceson, Ian
The reproductive biology and fishery-related characteristics of the Malabar grouper (Epinephelus malabaricus) (Bloch and Schneider, 1801) specimens were investigated. The size of females ranged from 25 to 113 cm total length (𝐿𝑇), with 50% sexually mature at 79 cm 𝐿𝑇, and the males (97 cm to 114 cm 𝐿𝑇) were larger than the females. Due to the sex ratios and size distribution of the sample, it appeared that the groupers change sex between 97 and 113 cm 𝐿𝑇. However, the gonadal histology data lacked specimens in the transitional stage. The spawning peak occurred in November, as defined by the presence of ripe females, and the spawning season lasted from September to February. The size of the fish correlated positively with the water depth at capture, which is also related to oxygen levels in deep water being more favourable for larger fish. Larger specimens (>100 cm𝐿𝑇) were targeted by fishers between December and February, when the northeast monsoon coincides with calmer weather and the spawning season. Fishers were interviewed, and observations were made on fishing gear, vessels, and grounds. There was no indication that small-scale fishers targeted spawning aggregations; therefore, fisheries independent research is recommended in order to verify the time, location, and behaviour of the spawning of Malabar groupers for management and conservation purposes.
Temporal and spatial trends in size, biomass and abundance of groupers (Epinephelinae) in Mafia Island Marine Park: fishers’ perceptions and underwater visual census surveys
(Fisheries Management and Ecology, 2015) Gaspare, Lydia; Bryceson, Ian; Mgaya, Yunus D.
Fishers’ perceptions of changes in grouper size and abundance were compared with scientific data collected via underwater visual censuses (UVCs) before (1995) and after (2006 and 2011) the establishment of the Mafia Island Marine Park. Perceptions on changes in the size structure of groupers differed among communities due to differences in fishing capacities. Fishers in one village had mixed perceptions, while in another village the majority (66%) perceived a decline in size, with small groupers dominating the catch. Similarly, UVCs indicated that size structure was dominated by small groupers at all times surveyed. Consistent with fishers’ perceptions, UVC indicated that biomass and abundance of groupers declined in both no-take zones (NTZs) and specified-use zones (SUZs) between 1995 and 2006, with no substantial changes between 2006 and 2011. The NTZs had higher density and diversity of grouper species than SUZs, as would be expected from the differences in bottom topography in these two types of areas. The idea that NTZs could increase the biomass and abundance of groupers to benefit fished zones was not found, thus indicating that NTZs are not necessarily the best option for managing reef fisheries.

Browsing by Author "Gaspare, Lydia"

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