Fisheries including tunas play a significant role in contributing to the national economy. The
management and development of tunas in Kenya has been challenged by the paucity of information
and knowledge on this fishery. The main objective of this study was to interrogate the scientific
robustness of the Kenya national fisheries policy and legal framework on tuna management in the
country. The study sourced catch data from primary and secondary sources. Fish samples from
artisanal catches were collected monthly from August 2015 to December 2016 from five landing
sites at the Kenyan coast; Amu (Lamu), Shella (Malindi), Mnarani (Kilifi), Watamu and Old Town
(Mombasa). Historical catch data from 24 foreign flagged longline tuna fishing vessels licensed to
harvest fish in Kenya Exclusive Economic Zone (EEZ) for the period February 2012 to March
2017 was obtained from Kenya Fisheries Service (KeFS). These data sources were complemented
by literature reviews, interviews and field visits. The data and information collected was analyzed
and used to assess the temporal and spatial variation in fish catch rates, species composition and
distribution, size distribution, growth parameters and mortality rates for some artisanal fishery
species. A total of 2686 individuals of tunas weighing 31,672 Kg representing 15 species, 13
genera and three families (Scombridae, Istiophoridae and Xiphiidae) from artisanal fishery were
sampled. Results of this study revealed that Thunnus albacares, Xiphias gladius and
Scomberomorus spp significantly contributed to the coastal fishery in Kenya accounting for 40%,
27.7% and 8%, respectively, of the total catch of tunas sampled. Fish catch rates varied with sites
with Amu recording the highest CPUE of 23.7 KgFisher-1Trip-1
, closely followed by Mombasa
with 19.16 KgFisher-1Trip-1
. Watamu, Shella (Malindi) and Mnarani recorded 11.1 KgFisher-1Trip-
1
, 7.5 KgFisher-1Trip-1
and 6.2 KgFisher-1Trip-1
, respectively. Fish catch rates varied monthly with
low catch rates reported from December 2015 to April 2016. The highest CPUE of 21.6 KgFisher-
1Trip-1 was recorded in the month of August 2015 while the lowest, 3.0 KgFisher-1Trip-1
, was
observed in December of the same year. Most of the tunas were landed during the South East
Monsoon (SEM) between May to October. Results of the 24 longline tuna vessels flagged to six
countries (China, Taiwan, Oman, Seychelles, Spain and Mauritius) fishing in the Kenya Exclusive
Economic Zone (EEZ) indicate that a total of 1833 individuals of tunas weighing 1,519,398 Kg
were harvest based on the declared catch. Thunnus albacares, Katsuwonus pelamis and Thunnus
obesus dominated the catch accounting for 43%, 29% and 17% of the total catch, respectively.
Analysis of Similarities (ANOSIM) of catch composition indicated significant differences been
vessels flagged to different states. Vessels flagged to Spain and Seychelles contributed 48% and
27% of the total catch, respectively. Vessels falged to Mauritius recorded the highest CPUE of
42,000 KgVessel-1Trip-1
followed by Spain with 5,392.6 KgVessel-1Trip-1
. Results of the analysis
for the size distribution, life history strategies, mortality and exploitation rates indicated that over
90 % of Thunnus albacares and Xiphias gladius sampled in artisanal fishery were juveniles.
Exploitation rates were also above the optimal indicating that the two fisheries are experiencing
growth overfishing. A review of the Kenya fisheries policy and legislative framework reveals that
it is coherent with the regional and international law with focus to scientific aspects. However, the
challenge is with effective implementation of tuna fishery management and development measures
informed by science, in particular biological aspects namely the Total Allowable Catch (TAC),
Total Allowable Effort (TAE) and precautionary approach. Information generated by this study
will certainly broaden the scientific knowledge and understanding about tunas in Kenya and inform
policy for their effective conservation and management.