Reef Ecology and Fisheries Analysis in Diani-Chale, southern Kenya: A GIS & RDBMS application Jelvas Mwaura 4 th. Symposium on GIS/Spatial analysis in Fisheries Sciences and Management
Nearshore reef fishery in Kenya Artisanal fisheries Main source of livelihoods Multi-species fishery Multiple fishing gears Management issues: High dependence on reef resources Growing coastal population/increased need for consumption limited economic alternatives Research and monitoring activities to help assess and guide future reef-fisheries fisheries management
Participatory Reef-fishery fishery Monitoring project 2001 to 2006 Habitat surveys:benthic covers (hard coral, rubble, algae, sand, soft coral) Reef fish populations:underwater Visual Census for all species Invertebrates: sea cucumbers, clams, sea urchins Fish catch records:catch amount, gear used, sites visited The need for effective systems that can serve to support assessment and management
Objective To illustrate the significance of combining relevant tools for inshore reef-fisheries fisheries assessment and management A RDBMS A GIS Data access and integration Management decisions:spatial information
Diani_Chale reef,southern Kenya Fishermen naming of their fishing grounds: 41 sites Extensive fringing reef with reef gaps About 0.5 to 2km from shore Use dugout canoes for fishing
How R-database and GIS integration works on collected data ArcGIS 9.1 GIS-output Fishermen-participation in reef monitoring project RDBMS 1. Reef fish 2. Benthic cover GIS Querry and Display 3. Invertebrates y 4. Fish catch 5. Gear types 6. Sites GPS Ecological data on reef benthic, fish, inverterbrates rtisanal Fishing data on catch amount, gear used, site use record Spatial data Representation Interpretation & Understanding for spatial Management decisions
Results- A functional RDBMS structure Table name No. Of Records Reef fish 4,567 Fish families 38 Fish catch 22,390 Benthic_cover 7,259 Benthic_cover types 8 Sea urchins 4,838 Sea urchins species 5 Other invertebrates 1,620 other invertebrates types 8 Fishing gear types 9 Monitored_Sites 47 Landing_stations 7 Interlinkage of numerous tables containing different data Efficient and accurate access to required data
Geospatial representation of Data What is the spatial distribution of fish abundance? Low High High fish abundance on outer reefs than inner reefs
Selected fish families 14 fish families selected economic value and ecological importance) High value fish species ; serranidae, lutjanidae, Lethrinidae (very low densities). Low value fish species; Acanthuridae, labridae, scaridae (most abundant) Balistidae and chaetodontidae (lowest population p densities)
What areas are productive? High-catch rates near the outer reefs and reef passes Lower catches close to the beach.
Temporal dimensions Not stable trends Stable trends only on outer reefs
What areas are healthy? Desirable benthic features High % hard coral (HC) Low % macro algae (AF) Low %rubble (RB) Fishing sites are labeled by benthic quality indicators Most of fishing grounds are have high % of rubble and macro algae than hard coral Destructive fishing practices:seine net dragging
Sites that are productive and healthy Only two fishing sites: outer reefs Most sites are degraded and fish depleted
Artisanal fishing pattern M t f t d it h d hi h t t l t t d fi h b d Most frequented sites had high total return amount,good fish abundance (outer reefs) while inner reefs were mostly degraded and depleted of resources: easy accessibility and destructive fishing practices
Discussions RDBMS-GIS model approach Compatibility of the two systems is an important asset A GIS role is to output spatial information from R- database Assessment and management fast and efficient data access, disparate data integration and easy generation of different geospatial data layers GIS clarifies the issues more explicit:enhances spatial decisions on fisheries management Management based at site level may be more effective than focusing on entire reef unit
Conclusion cuso The application of a RDBMS-GIS is a clear proof concept of technology: efficient i data access and enhanced information source. prime focus for any fishery assessment and management
Acknowledgement Travel Grant: WIOMSA
Thank you! Obligado!