Browsing by Author "Semba, Masumbuko"

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Caudal fin as a proxy for dorsal muscle for nutrient enrichment monitoring using stable isotope analysis: the case of Gerres filamentosus and G. oyena from mangrove creeks of Tanzania
(Western Indian Ocean Journal of Marine Science, 2022) Lugendo, Blandina; Igulu, Mathias; Semba, Masumbuko; Kimirei, Ismael
The use of fish dorsal muscles in stable isotope studies, which is an invasive method that results in fish deaths, limits their applicability for rare and endangered fish species, as well as when large sample sizes and replicates are required, prompting research into feasible non-lethal sampling methods. The possibility of employing fin clippings (a non invasive approach) was investigated as a proxy for dorsal muscle in nutrient pollution monitoring studies using two common mangrove fish species, namely Gerres filamentosus and G. oyena, which are known to spend their early life stages primarily within mangroves. The dorsal muscles and caudal fin tissues of fish from the mangrove creeks of Kunduchi and Mbegani, Tanzania, were examined for 13C and 15N signatures. Dorsal muscles from Kunduchi (mean SD: 13C = -16.8 ± 2.86, 15N = 9.34±1.15) were more enriched than from Mbegani (mean SD: 13C = -18.60 ± 2.11, 15N = 7.27±1.09), and this enrichment was consistent across the two studied species. Caudal fins indicated similar enrichment trends. Fin tissue stable isotope values explained between 62 % and 87 % of dorsal muscle 13C and between 89 % and 98 % of dorsal muscle 15N variability. These findings support the use of fin-clipping as a non-lethal proxy for stable isotope analysis of the studied species for nutrient enrichment, and additional research into non-lethal sampling methods is recommended.
Co-management of Lake Victoria Fisheries
(Springer Nature Switzerland AG., 2017-11-29) Mahatane, A.; Mgaya, Yunus D.; Hoza, R. B.; Onyango, P. O.; Semba, Masumbuko
There have been concerns about the declining fish catches and fisheries ecosystem health for a number of fisheries including Lake Victoria. Consequently, a co-management system has been introduced as a means of, among others, reversing the declining catches. It is hypothesized that non-involvement of fishers in the management of the lake’s fisheries is a major reason for the ever-decreasing catches. This chapter discusses this particular management regime and its application in the lake’s fisheries. The analysis is based on data collected by the Fisheries Division since co-management was introduced in the lake in 1998. The chapter traces the lake’s fishery management since the pre-colonial to the post-colonial period. It presents the aim and rationale for managing the lake’s fishery, the structure of the management and roles of governors. It also analyses trends in illegal fishing practices as well as enforcement performance. The argument here is that co-management has helped in bringing on board fishers and this has enabled laws and regulations to be implemented in a much better way than they were under a central-command system. The chapter subsequently concludes that the involvement of fishing communities in the management of fisheries has created a forum for the exchange of ideas, knowledge and experience on the resources. This strategy has made the communities understand the importance of compliance to the law and regulations and effective management measures.
Coastal upwelling and seasonal variation in phytoplankton biomass in the Pemba Channel
(African Journals Online, 2021-02-11) Kyewalyanga, Margareth S.; Peter, Nyamisi; Semba, Masumbuko; Mahongo, Shigalla B.
This study was conducted in the Pemba Channel off Tanga Region in northern Tanzania to investigate physical and chemical factors that drive changes in phytoplankton biomass. Three transects off Mwaboza, Vyeru and Sahare were selected. For each transect, ten stations were sampled. Phytoplankton biomass was determined as chlorophyll-a (Chl-a) concentration. Similarly, physico-chemical variables (temperature, salinity, dissolved oxygen, pH and nutrients) were determined. It was observed that the Chl-a concentration was significantly higher during the northeast monsoon (median 1.44 mg m-3) as compared to the southeast monsoon (median 1.19 mg m-3; W = 2216, p = 0.029). The higher productivity during the northeast monsoon is attributed to the presence of high-nutrient water caused by coastal upwelling. It is concluded that indication of upwelling, observed through relatively low temperatures during the northeast monsoon season, could be responsible for bringing nutrient-rich waters to the surface, which in turn stimulated the increase in Chl-a concentration.
The decline in phytoplankton biomass and prawn catches in the Rufiji-Mafia Channel, Tanzania
(African Journals Online, 2016-11-27) Semba, Masumbuko; Kimirei, Ismael; Kyewalyanga, Margareth; Peter, Nyamisi; Brendonck, Luc; Somers, Ben
The world’s oceans have seen significant declines in phytoplankton-the primary food source in the marine environment. This decline in primary producers is likely to impact the food chain and functions of most coastal and marine ecosystems. Despite being one of the most productive marine fishing grounds in the Western Indian Ocean (WIO) region, the information about phytoplankton biomass in the Rufiji-Mafia Channel is poor. This study aimed to narrow this information gap by assessing phytoplankton biomass in the Channel and its association with the decline of the prawn fishery. We combined in-situ measurement and ocean colour satellite data to determine and assess trends in phytoplankton biomass and sea surface temperature between 2002 and 2014. These trends were related to a declining prawn fishery in the Channel. While phytoplankton displayed a significant declining trend during the southwest monsoon, sea surface temperature showed an insignificant increasing trend. Phytoplankton declined at the rate of 1.2 percent per year (tau = 1.2, z = 3.52, p = 0.004) between 2002 and 2014. This declining trend in Chl-a matches well with the decreasing trend in the prawn fishery (tau = 0.57, z = 3.39, p = 0.0006) and the insignificant increasing trend in sea surface temperature (tau = 0.02, z = 0.43, p = 0.66). This study provides quantitative evidence of trends in chlorophyll and SST and the link with trends in the prawn fishery, which increases our understanding of the changes in marine primary productivity in the coastal waters of Tanzania.
Ecological Changes in the Zambezi River Basin
(African Books Collective, 2021-11) Semba, Masumbuko; Murisa, Mzime; Mubaya, Chipo; Kimirei, Ismael; Chavula, Geoffrey; Mwedzi, Tongayi; Maravanyika, Tendayi; Zenda, Sandra
Africa faces a plethora of challenges and chief among these is a change in the climate (Zakaria and Maharjan 2014) which is one of the key factors affecting the ecology and hydrology of its river basins (Kusangaya et al. 2014). Beilfuss (2012) proposed that Africa’s arid regions are highly vulnerable to climate change with the Zambezi River Basin (ZRB) being particularly at risk (Kling et al. 2014). After the Nile and Niger rivers, the ZRB is the next most trans-boundary river basin in Africa as it serves eight African countries. Consequently, water resource development planning is crucial, since any changes in climate will impact the hydrological cycle and the amount of water retained in hydrological systems (Beilfuss 2012) of which only up to 3 per cent is readily available as usable and shared freshwater. Like some Sub-Saharan countries, which have experienced up to 0.5 C increases in temperature (Hendrix and Glaser 2007), the Zambezi River Basin is also facing changes in climate (Ndhlovu 2013). A recent study by Kling et al.(2014) reported rises in temperature and more variable precipitation in the basin since the 1980s. Such historical climatic changes, and those projected towards the mid-century (2050), are of concern with serious social and economic implications to local communities (Mubaya et al. 2012). The Intergovernmental Panel on Climate Change (IPCC) projected a global decadal temperature rise of 0.2 C (IPCC 2007). However, regional climate
Environmental Changes in the Tanzanian Part of Lake Victoria
(Springer Nature Switzerland AG., 2017-11-29) Kimirei, I. A.; Semba, Masumbuko; Mwakosya, C.; Mgaya, Yunus D.; Mahongo, Shigalla B.
Lake Victoria is known for its explosive speciation and recent time hybridization, which is highly mediated by deterioration of water quality. This chapter summarizes the knowledge on change of water quality and environment of southern part of Lake Victoria, Tanzania. It analyses rainfall, air temperature and water quality data spanning 30 years (1985 to 2015). It also investigates changes in physical-chemical data sampled during and after the Lake Victoria Environmental Management Project I (LVEMP I). The chapter reviews some of the significant water quality changes that have occurred for the past 50 years. The results indicate no significant changes in annual rainfall variability. Nevertheless, trends of air temperature showed no clear patterns for Mwanza and Musoma, but trends of minimum and maximum air temperature in Bukoba increased significantly at annual rates of 0.19 °C and 0.14 °C, respectively. Water level in Lake Victoria has also declined significantly at an annual rate of about 5.5 cm from 1965 to 2004. These findings suggest that lake levels are determined by evapotranspiration rather than rainfall. It was also found that anthropogenic stressors are more important in explaining nutrients loading while thermal stratification explains hypoxia and reduction in water mixing. It is concluded that the current blooms of harmful algae and excess biomass in Lake Victoria will continue unabated unless nutrient loading, anoxia and high rates of denitrification are curbed. Appropriate measures to improve land use management should therefore be taken, while deliberate dumping of industrial, municipal and agricultural wastes into the lake should be controlled.
Fisheries Statistics for Lake Victoria, Tanzania
(Springer Nature Switzerland AG., 2017-11-29) Sobo, F.; Mgaya, Yunus D.; Kayanda, R. J.; Semba, Masumbuko
Time series fisheries statistics data mainly from Frame Surveys, Catch Assessment Surveys and Fisheries Annual Statistics Reports for Lake Victoria from 1967–2016 were collected from the Fisheries Development Division in Tanzania. These surveys and reports comprised relevant information and data on fish catches and fishing effort. The data were analysed and used to describe variations and trends in the number of fishers, number of fishing crafts, fish weight, catch per boat, total number of gillnets, beach seines, longline hooks, outboard and inboard engines. Frame Survey results showed an increasing trend in the number of fishers and fishing crafts, with the highest number of fishers and fishing crafts being 109,397 and 31,773, respectively in 2016. Longline hooks increased from 2,200,901 in 2000 to 8,163,119 hooks in 2016. In general, the catch per unit effort (CPUE) for all species was high at 39 mt/boat/year in 1967 and decreased to 8 mt/boat/year in 2014. However, CPUE for Lates niloticus has increased since the late 1980s, with the highest CPUE of 19.22 mt/boat/year being recorded in 1995, and from 2000 it decreased gradually to 7 mt/boat/year in 2014. As the fisheries statistics show an increase in fishing pressure over the years, it is evident that there is a sign of overfishing. For that matter, effective fisheries management is needed for the three riparian states to safeguard the sustainable use of fishery resources in the lake and to provide data that can be used in the evaluation of the fisheries objectives.
Growth, mortality, exploitation rate and recruitment pattern of Octopus cyanea (Mollusca: Cephalopoda) in the WIO region: A case study from the Mafia Archipelago, Tanzania
(Western Indian Ocean Journal of Marine Science, 2021-08-24) Silas, Mathew; Kishe, Mary; Mshana, Johnson; Semba, Masumbuko; Mgeleka, Said; Kuboja, Bigeyo; Ngatunga, Benjamin; Chande, Muhaji; Matiku, Patroba
Octopus cyanea is a commercially important cephalopod in the Western Indian Ocean (WIO) region, but scientific information to inform management strategies for the species is limited. A study was conducted in 2014, 2015, 2017 and 2018 to investigate biological parameters including growth, mortality, exploitation rates and recruitment patterns in the sea around Mafia Archipelago, Tanzania. Virtual population analysis (VPA) indicated differential mortality between two sampling sites; the lowest and highest fishing mortality of F = 1.5yr-1 and F = 2.7yr-1 were observed in Bwejuu (Dorsal mantle length, DMT = 18-20 cm) and Jibondo (DMT = 8-12 cm) fishing villages, respec tively. The maximum exploitation rate (Emax), which gives the maximum relative yield per recruit, was estimated at 0.380 and 0.379 for Jibondo and Bwejuu, respectively. The exploitation rates E 0.5, which corresponded to 50% of the unexploited stock relative biomass per recruit, were estimated at 0.248 for Jibondo and 0.247 for Bwejuu. These values differ greatly from the exploitation rates of 0.53 and 0.41 for Jibondo and Bwejuu, respectively, sug gesting that the stock of O. cyanea is probably being overfished both in terms of yield per recruit and biomass per recruit. The stock-recruit pattern was observed to be continuous year-round, with the peak being between May and July. Since the peak in recruitment of both areas coincides with the south-east monsoon (SE Monsoon) and the level of maximum sustainable yield has been overshot, it is recommended that management plans are implemented that will reduce effort while increasing biomass, for example, implementing temporal octopus fishery closures at a village level.
High-frequency dynamics of pH, dissolved oxygen, and temperature in the coastal ecosystems of the Tanga- Pemba Seascape: implications for upwelling-enhanced ocean acidification and deoxygenation
(Frontiers, 2024-01-08) Job, Samson; Semba, Masumbuko; Monga, Elinasi; Lugendo, Blandina; Tuda, Arthur; Kimirei, Ismael; Rushingisha, George;
Ocean acidification, deoxygenation, and warming are three interconnected global change challenges caused by increased anthropogenic carbon emissions. These issues present substantial threats to marine organisms, ecosystems, and the survival of coastal communities depending on these ecosystems. Coastal upwelling areas may experience significant declines in pH, dissolved oxygen (DO), and temperature levels during upwelling events, making marine organisms and ecosystems in these areas more susceptible to ocean acidification and deoxygenation. Understanding the dynamics of pH, DO, and temperature in coastal upwelling areas is essential for evaluating the susceptibility of resident organisms and ecosystems to lower pH and DO conditions occurring during upwelling events. To accomplish this, we used the pH and the DO loggers to measure high-frequency data for pH and DO, respectively, over six months in the open ocean and for a 24-hour cycle within the mangrove, seagrass, and coral reef ecosystems of the Tanga- Pemba Seascape (T-PS) during the northeast monsoon season. Our findings revealed the occurrence of multiple upwelling events, with varying durations, that result in significant declines in pH, DO, and temperature within the seascape. This is the first study to confirm the occurrence of multiple upwelling events in the T-PS. Moreover, the study has revealed a pH threshold value of 7.43 for ocean acidification in the T-PS. This is the first study to report a threshold value for ocean acidification in coastal upwelling areas of the Western Indian Ocean (WIO). Furthermore, it revealed that the extremely low levels of pH that occurred during upwelling events were above the pH threshold value of 7.43 for ocean acidification, while the extremely low levels of DO fell below the oxygen threshold value of 4.6 mg/L for deoxygenation. During upwelling events, seagrass and coral reef ecosystems,but not mangrove ecosystems, demonstrated elevated mean hourly values of pH and DO compared to those of the open ocean. These findings show that marine organisms and ecosystems in the T-PS are frequently exposed to lower pH and DO conditions due multiple upwelling events. However, their susceptibility to these conditions is reduced to some extent by the presence of seagrass meadows within these interconnected systems.
The influence of physical-chemical variables on the spatial and seasonal variation of Chlorophyll-a in coastal waters of Unguja, Zanzibar, Tanzania
(African Journals Online, 2018-12-11) Peter, Nyamisi; Semba, Masumbuko; Lugomela, Charles; Kyewalyanga, Margareth S.
Chlorophyll-a (Chl-a) concentrations were measured at four sites around Unguja, Zanzibar during the northeast (NE) and southeast (SE) monsoon seasons. Data for Chl-a, nitrate, phosphate, ammonia, dissolved oxygen, sea sur-face temperature, pH and salinity were collected once a month from March 2008 to March 2009. The SE monsoon had insignificantly higher Chl-a compared to the NE monsoon season when Chl-a for Bawe, Chumbe, Pongwe and Mnemba were combined (W = 234, p = 0.93). The drivers of high Chl-a during the SE monsoon were ammonia and nitrate. Results from individual sites showed that Pongwe and Mnemba had higher median Chl-a during the SE- than the NE monsoon season. Temperature, dissolved oxygen and ammonia were the major factors that influenced high Chl-a at these sites. In contrast, Chumbe and Bawe had higher median Chl-a during the NE- than the SE mon-soon season. The major factors influencing high Chl-a in the NE at Chumbe and Bawe were high levels of nutrients, mainly from sewage effluent and various human activities around the coast in Zanzibar town. The interaction of Chl-a between monsoon seasons (NE and SE) and sites (Bawe, Chumbe, Pongwe and Mnemba) was insignificant (F(1,3) = 1.3144, p = 0.2949). The principal component analysis revealed that different physical and chemical environmental variables affect Chl-a concentration over time and location
Seasonal and spatial variation of surface current in the Pemba Channel, Tanzania
(PLOS ONE, 2019-01-07) Semba, Masumbuko; Lumpkin, Rick; Kimirei, Ismael; Shaghude, Yohanna; Nyandwi, Ntahondi
The surface current speeds within the Pemba channel were examined using 24 years of drifter data received from the Global Drifter Program. This study aimed to uncover varying surface current in the Pemba Channel in different seasons. The results revealed the Pemba Channel experiences relatively higher median surface current speeds during the southeast (SE) monsoon season compared to the northeast (NE) and inter-monsoon (IN) periods. The strongest current speeds were confined in waters deeper than 200 meters between ~39.4°E and 39.7°E. These results prove that surface currents from the drifters can be used to uncover the patterns of surface circulation even in areas where in-situ measurements are scarce.
Seasonal variability of vertical patterns in chlorophyll-a fluorescence in the coastal waters off Kimbiji, Tanzania
(Western Indian Ocean Journal of Marine Science, 2021-09-24) Peter, Nyamisi; Semba, Masumbuko; Lugomela, Charles; Kyewalyanga, Margareth
A study on the vertical pattern of chlorophyll-a (Chl-a) fluorescence was undertaken in the Mafia Channel off Kimbiji, Tanzania. Data was collected during the Southeast Monsoon (SEM) and Northeast Monsoon (NEM) seasons. There was higher Chl-a concentration of 0.1 to 1.1 mgm-3 in the surface layer off Kimbiji to about 50 m depth due to the presence of mixed layer depth (MLD) which allowed water mixing in the layer. A deep Chl-a maximum was recorded at around 40 m depth during the NEM and between 40 and 70 m in the SEM. Surface water between lon gitude 39.9°E and 40.2°E had low Chl-a from the surface to about 50 m depth due to poor nutrient input. The NEM had an insignificantly higher Chl-a value than the SEM (p > 0.05) which differed from other studies in which Chl-a was higher during the SEM than the NEM, than, the Chl-a concentration was higher at the surface during the SEM than during the NEM. Satellite data showed higher Chl-a in the SEM than NEM, localized along the Mafia Channel. During the SEM season the wind pushes higher Chl-a water from the Mafia Channel towards the north and leads to a higher concentration at Kimbiji
Small Estuarine and Non-Estuarine Mangrove Ecosystems of Tanzania: Overlooked Coastal Habitats?
(Springer Nature Switzerland AG., 2016-03-23) Kimirei, I. A.; Igulu, M. M.; Semba, Masumbuko; Lugendo, B. R.
Small estuaries and non-estuarine habitats harboring mangroves are very important ecosystems which provide important ecosystem goods and services; such as provision of ecological niches for juvenile fishes and invertebrates, enhances fisheries, and in biodiversity conservation. Similar to large estuaries, they are highly perturbed which threatens their existence. This chapter uses beach seine, underwater visual census, and stable isotope data to discuss the importance of and threats to small estuaries and non-estuarine mangroves found in Dar es Salaam, Bagamoyo and Zanzibar, Tanzania. For example, mangroves of Kunduchi (Dar es Salaam) and Mbegani (Bagamoyo) which harbour predominantly higher densities of juveniles (≤10 cm) of two economically important species—Lutjanus fulviflamma and Lethrinus harak—than adjacent coral reefs. Evidence suggests further that the Kunduchi mangroves replenish fish populations on adjacent coral reefs; where over 90% and 29% of adult L. fulviflamma and L. harak individuals, respectively, have been identified to have lived in the mangroves as juveniles. In terms of habitat utilization by different size classes of fish, five of the 13 species (Lethrinus lentjan, L. variegatus, Pelates quadrilineatus, Siganus sutor and Sphyraena barracuda) found in Chwaka Bay (Zanzibar) were found as small-sized individuals in shallow and turbid mangrove areas with large juveniles and sub-adults in adjacent seagrass beds. The non-estuarine mangroves of Kunduchi and those of Mtoni estuary (Dar es Salaam) are subjected to pollution from urban activities. For example, stable isotope data of fishes indicate elevated levels of nitrogen in these mangroves with highest levels (δ15N = 15.2 ± 0.2) recorded in Mtoni estuary. In view of their importance and threats they face, these ecosystems require attention similar to large estuaries. If the current degradation rate of these ‘overlooked’ but equally important ecosystems continues, they may be declared ‘functionally disappeared’ in a few decades.
Small Estuarine and Non-Estuarine Mangrove Ecosystems of Tanzania: Overlooked Coastal Habitats?
(Springer International Publishing, 2016-03-23) Kimirei, A; Igulu, Mathias; Semba, Masumbuko; Lugendo, Blandina
Small estuaries and non-estuarine habitats harboring mangroves are very important ecosystems which provide important ecosystem goods and services; such as provision of ecological niches for juvenile fishes and invertebrates, enhances fisheries, and in biodiversity conservation. Similar to large estuaries, they are highly perturbed which threatens their existence. This chapter uses beach seine, underwater visual census, and stable isotope data to discuss the importance of and threats to small estuaries and non-estuarine mangroves found in Dar es Salaam, Bagamoyo and Zanzibar, Tanzania. For example, mangroves of Kunduchi (Dar es Salaam) and Mbegani (Bagamoyo) which harbour predominantly higher densities of juveniles (≤10 cm) of two economically important species—Lutjanus fulviflamma and Lethrinus harak—than adjacent coral reefs. Evidence suggests further that the Kunduchi mangroves replenish fish populations on adjacent coral reefs; where over 90% and 29% of adult L. fulviflamma and L. harak individuals, respectively, have been identified to have lived in the mangroves as juveniles. In terms of habitat utilization by different size classes of fish, five of the 13 species (Lethrinus lentjan, L. variegatus, Pelates quadrilineatus, Siganus sutor and Sphyraena barracuda) found in Chwaka Bay (Zanzibar) were found as small-sized individuals in shallow and turbid mangrove areas with large juveniles and sub-adults in adjacent seagrass beds. The non-estuarine mangroves of Kunduchi and those of Mtoni estuary (Dar es Salaam) are subjected to pollution from urban activities. For example, stable isotope data of fishes indicate elevated levels of nitrogen in these mangroves with highest levels (δ15N = 15.2 ± 0.2) recorded in Mtoni estuary. In view of their importance and threats they face, these ecosystems require attention similar to large estuaries. If the current degradation rate of these ‘overlooked’ but equally important ecosystems continues, they may be declared ‘functionally disappeared’ in a few decades.
Small Scale Fisheries Management: Lessons from Cockle Harvesters in Nicaragua and Tanzania
(Taylor & Francis Online, 2010-06-01) Crawford, Brian; Herrera, Maria D.; Herrera, Herrera; Leclair, Carlos Rivas; Jiddawi, Narriman; Semba, Masumbuko; Haws, Maria
The role of women in gleaning fisheries tends to be underestimated and poorly documented although they play an important role in coastal food security and income generation. This article describes two initiatives for co-management of women dominated cockle (Anadara spp.) fisheries implemented in Zanzibar Island of Tanzania and in Nicaragua that were based on a Fiji model. In each case, significant progress was made at the pilot scale but required adaptation to the community and national context. The Nicaragua case resulted in increasing densities of cockles inside and outside small scale no-take zones in a small estuary after a two-year period of implementation. In Zanzibar, out of several no-take sites established on reef flats, only one showed similar results. Other sites’ poor performance is likely due to poor site selection, small size, and non-compliance. Varying degrees of poaching affected both locations and continues to be an issue. In Zanzibar, local and national government played highly supporting roles whereas in Nicaragua, local government was supportive but national government continues to exhibit top-down decision-making, while still evaluating the alternative co-management approach. In both cases, university extension initiatives were influential in building community capacity for management and playing an advocacy role with national government. Both locations are poised for scaling up to more geographic sites as well as fostering policy change that can lead to more integrated and ecosystem-scale approaches to sustainable fisheries management.
Using fishers’ local ecological knowledge for management of small-scale fisheries in data-poor regions: Comparing seasonal interview and field observation records in East Africa
(Elsevier, 2023-08) Silas, Mathew; Semba, Masumbuko; Mgeleka, Said; Well, Lisa; Linderholm, Hans; Gullström, Martin
Fishers, scientists and policy makers need to describe, understand and “agree on” variations in fish catches caused by exploitation and climate change for effective fisheries management. To achieve this, relevant data with sufficient spatiotemporal resolution is a necessity. In regions of the Global South, such as the Western Indian Ocean (WIO), fish catch data useful for management is scarce or non-existing. Still, the potential of local ecological knowledge to provide such information has not been fully utilised in these regions. In this study, we evaluated fishers’ local ecological knowledge (based on interviews) against detailed seasonal fish catch variability data based on catch per unit effort (CPUE) records. Because of the importance of the monsoon seasons for marine resource variability, differences in fish catches during the northeast (NE) and southeast (SE) monsoon seasons were investigated. Fishers’ perceptions generally agreed with catch data records, both showing that the NE monsoon season generally provides higher catch rates than the SE monsoon season. The fishers’ perceptions at two of the landing sites (Nyamisati and Shangani) contradict the recorded observations by showing highest fish catches during the SE monsoon season. It was clear, however, that fishers’ perceptions in these two sites focused on the most valuable target species (prawn and tuna in Nyamisati and Shangani, respectively) rather than total catches. In this particular case, fishers’ perceptions facilitated the significance of taking target species into consideration. The findings of this study highlight the importance of integrating local ecological knowledge into scientific research to help understand the complex dynamics of coastal fisheries and improve the management of data-poor fisheries.