Managing emerging fisheries of the North Kenya Banks in the context of environmental change

The North Kenya Banks have long been considered an important emerging fishery with the potential to spur economic growth for local fishing communities. As a regionally important extension to the otherwise narrow East African continental shelf, the North Kenya Banks remain under studied with implications for efforts to develop a sustainable fisheries management strategy. The local marine ecosystem is known to be strongly influenced by wind driven upwelling processes with seasonal variability driven by the changing monsoon seasons being of particular importance. Nevertheless, the Western Indian Ocean is warming due to anthropogenic climate change with evidence indicating reduced ocean productivity in future. How the ecosystem of the North Kenya Banks will respond is currently uncertain but is of great importance due to the significance of coastal fishery resources to coastal communities, and growing Blue Economy initiatives to exploit the North Kenya Banks fisheries more widely. There is, however, limited knowledge of the processes influencing productivity over the North Kenya Banks regions and currently there is no management plan in place to sustainably manage the fishery resources. Here, information about the North Kenya Banks fisheries are examined in relation to environmental processes and threats from climate change impacts with suggestions for future research and management directions

Current status of sea turtle protection in Lamu Seascape, Kenya: Trends in nesting, nest predation and stranding levels

Temporal and spatial trends in sea turtle nest protection, predation and mortalities in the Lamu archipelago, Kenya were investigated based on nesting beach monitoring efforts conducted among five locations comprising 34 beaches. The nesting data was collected for a period of 17 years from 1997 – 2013 through beach patrols using standardized protocols while mortality data spanned from 2001 – 2013.  The causes of mortality were determined through general external examination. The green turtle, hawksbill, olive ridley and loggerhead turtle were recorded in the area. Out of a total of 2,017 nests recorded, 64.4% (n = 1299) were translocated while 10.2% were predated. Predation levels were not significantly affected by seasonality (p > 0.05); although the levels were lower during the wet Southeast Monsoon (SEM) season (9.2 ± 2.2 %) compared to the Northeast Monsoon (NEM) season (14.8 ± 3.0 %). A total 227 mortality cases were recorded between 2001 and 2013 of which fishery- related causes were the highest representing 53%. This was followed by unknown causes which constituted 20%, shark attacks (13%) and the tumor causing viral disease fibropapillomatosis (11%). Overall, the highest number of mortalities was recorded for Mkokoni (35%) while the lowest was recorded for Mvundeni (4%). Green turtles comprised 79% of the mortality cases recorded with a mean size range of 68.9 ± 1.9 cm CCL. The incidences of mortality occurred year-round; however, the incidence of strandings was higher during the dry NEM season in the months of January to March when fishing effort is also highest. The success of sea turtle conservation efforts in the Lamu seascape is clearly demonstrated by the increased nesting activity over time, as well as the reduced trend on sea turtle nest predation levels. To continue this success, it is vital that sea turtle conservation efforts including a comprehensive monitoring programme are supported

Biodiversity data rescue in the framework of a long-term Kenya-Belgium cooperation in marine sciences

The Kenya-Belgium data collection includes about 111,800 biotic observations on benthos, algae, fish, zooplankton, phytoplankton, birds and mangroves which cover more than 400 unique locations that were sampled between 1873 and 1999. The scope of this data digitization project was to recover data in theses and reports resulting from marine and coastal research activities in the Eastern African region conducted between 1984 and 1999. Data were digitized and quality checked in the frame of the Belgian LifeWatch project. The dataset provides a better insight into the different types of research conducted between 1985 and 1996 in frame of the Kenya-Belgium cooperation in marine sciences (KBP) project and can facilitate further coastal biodiversity research in Kenya

Length-weight relationship of selected teleost fishes from Kilifi County, Kenya

Sustainable exploitation of fishery resources requires knowledge of the population dynamics of the target resources. Length-weight relationship and relative condition parameters were determined for nine teleost fish species, Calotomus carolinus (Valenciennes, 1835), Decapterus macrosoma (Bleeker, 1851), Lethrinus nebulosus (Forsskal, 1775), Lethrinus harak (Forsskal, 1775), Lutjanus fulviflamma (Forsskal, 1775), Rastrelliger kanagurta (Cuvier, 1816), Sargocenton caudimaculatus (Ruppel, 1838), Scomberoides tol (Cuvier 1832) and Siganus sutor (Valenciennes, 1835). The fish were randomly collected from artisanal fishers who operated gears such as gill nets, spearguns and basket traps at three landing sites in Kilifi County between February and April 2017. The linear regression revealed a positive relationship between total length and body weight in all the fish sampled. The t-test calculated on b for most species revealed no significant deviations from the expected cube value of three, except for L. nebulosus (t=0.340, p<0.05), R. kanagurta (t=1.321, p<0.05) and S. sutor (t=0.961, p<0.05). These fish populations are healthy as shown by a relative condition factor above 1 in all species, suggesting that the nutritional requirements are available in the ecosystem, and that the Kilifi coral reefs have thus not been degraded.

Gear-based species selectivity and potential interactions between artisanal and aquarium fisheries in coastal Kenya: implications for reef fisheries management

Due to the multigear, multi-species and open-access nature of most coral reef fisheries in the Western Indian Ocean region, there is a high potential for resource competition and fishing related conflicts, especially in shared fishing grounds. An understanding of resource overlap and competition between different co-occurring fisheries is therefore important for the implementation of ecosystem based fisheries management interventions. In this study, we used multivariate and ecological approaches to evaluate gear competition and interactions between artisanal and  aquarium fishers using a case study of the Shimoni area, southcoast of Kenya. Aquarium fisher catches were monitored from September 2010 to March 2013; while artisanal fisher catches were monitored from January to December 2014. Five artisanal gear types were observed to interact with the aquarium fishery. Non-target species valued by the aquarium trade constituted approximately 12% of the artisanal catches by weight and 10% by relative abundance, and was comprised of 18 fish families and 57 species. Handlines captured the highest number and diversity of non-target species while the lowest was observed for gillnets. The findings contribute towards better understanding of the dynamics of resource overlap between artisanal and aquarium fisheries on a local scale, and provide new insights on the cumulative sources of fishing pressure affecting reef fish populations in Kenya

Comparing fish bycatch of shrimp trawlers with catches made by artisanal fishers in Malindi-Ungwana Bay, Kenya

Unpredictable weather patterns has affected both the agriculural and fisheries production worldwide coupled with increased conflict in resource use. The Malindi-Ungwana Bay, Kenya in Tana Delta has multiple socio-economic uses and therefore, has been a subject of resource use conflict for a long time. This present study identifies resource use overlap and conflict by comparing species composition, distribution patterns and abundance of bottom trawl fish bycatches and artisanal fish catches in the bay. Bottom trawl surveys were undertaken during the dry Northeast Monsoon (NEM) season and during the wet Southeast Monsoon (SEM) season in 2011, and artisanal catches were sampled along the bay between 2009 and 2011. Bottom trawl fish bycatches consisted of a total of 223 species against a total of 177 species for artisanal catches. Higher species diversity was associated with the bottom trawl bycatches and was significantly higher in the wet SEM season and in the inshore area of the bay. Trawl bycatch rates and biomass were significantly higher in inshore than offshore areas and distinct in composition but less differing between the seasons.  Similarity in catch composition was evident between the artisanal catches and bottom trawl bycatches in the inshore area. This similarity was attributed mainly to 7 common and most abundant fish species associated with the artisanal and bottom trawl sub-sectors confirming the existence of a potential but localised inshore resource use overlap. Furthermore, significantly smaller sized individuals of these 7 species occurred in the trawl bycatches which may affect fish recruitment with continued trawling. Artisanal fishing activity in the bay is envisaged to increase due to decreased agricultural production. Sustainable artisanal fisheries will therefore, depend on the full implementation of the shrimp fishery management plan in the bay