OHI+ Kenya_Technical Report_2018

Ocean Health Index - Kenya 2018 36
Figure 8 Overview of the data analysis process within the OHI Toolbox. Source: Borja et al. 2016
(www.frontiersin.org/articles/10.3389/fmars.2016.00020/full)
9.5. Data and sources
Table 11. Available biodiversity and habitat data in Kenya
Report Title
Institution
Sensitivity Habitat mapping
KMFRI
Biodiversity assessments and coast-wide mapping KMFRI
Fishing ground habitat map for Lamu
WWF
National Mangrove management plan
KMFRI
Shoreline management strategy
NEMA
2 nd Edition of State of the Coast Report NEMA
9.6. Fisheries model and analysis
Food provision from wild caught fisheries is assessed by estimating population biomass relative to the
biomass that can deliver maximum sustainable yield (B/B MSY ) for each stock. When available, B/B MSY values
are obtained from the RAM Legacy Stock Assessment Database (Ricard et al., 2012), which contains stock
assessment information for a portion of global fish stocks. When RAM data were not available, datalimited
approaches are used. These approaches have been developed to estimate B/B MSY values using
globally available catch data (Costello et al., 2016, 2012; Martell & Froese, 2012; Thorson, Minto, Minte-
Vera, Kleisner, & Longo, 2013, Rosenberg et al. 2014). To calculate the status for each region and
year, B/B MSY values are converted to a stock status score between 0 -1 that penalizes both over- and
under-harvesting. To obtain the overall status for each region (x fis ), the stock status scores (SS) for all the
stocks within a region were averaged using a geometric mean weighted by the average catch (tonnes) of
each stock (C):
i is an individual taxon and n is the total number of taxa in the reported catch
for each region throughout the time-series, and C is the average catch, since the
first non null record, for each taxon within each region.