| dc.description.abstract | Hook and line are commonly used fishing gear in Kenya’s small-scale coastal and
marine fishery. The most abundant catches of this gear is made up of the fish family
Lethrinidae. Despite this wide usage of the gear along the Kenya coast, there is still
limited information on the effect of various sizes of hooks used in the hook and line
fishery on the target fish species. Therefore, this study assessed the sustainability of
the small-scale hook and line fishery on lethrinids by evaluating mortality and
exploitation rates, proportion of immature and undersized fish individuals landed
and catch per unit effort (CPUE) variations. Shore-based fish catch surveys were
conducted for ten days in a lunar month from July to December 2021 in the selected
fish landing sites of Mkunguni, Mwaembe, Kanamai and Mtwapa along the Kenya
coast. Hook sizes were categorized into three groups based on the standard
numbering system and comprised of large (No. 6 - 8), medium (No. 9 - 11) and small
(No. 12 - 14) hooks. Four lethrinid fish species dominated the catches, Lethrinus
borbonicus, Lethrinus lentjan, Lethrinus rubrioperculatus and Lethrinus mahsena, and
collectively accounted for 77.7% of the total fish landings. L. lentjan was found to be
heavily overexploited, L. borbonicus lightly overexploited and L. rubrioperculatus and
L. mahsena underexploited, compared to different yield-based exploitation rates
reference points. Lengths at first capture (Lc) for these four species were less than
length at maximum yield per recruit (Lopt) and length at first maturity (Lm).
Proportions of individuals below Lm and Lopt were high in small hooks (41-71% and
49-77%) compared to medium (35-51% and 45-62%) and large (<11% and 3-19%)
hooks, respectively. The CPUE differed significantly across hook size groups and
landing sites (p < 0.01) but not between seasons (p = 0.846). The high exploitation rate
for L. lentjan suggests the need for management measures to be put in place that will
prevent the stock from collapsing. The high vulnerability of L. mahsena to over
exploitation warrants precautionary management measures to maintain light levels
of exploitation for this species. The high proportion of individuals below Lm and Lopt
of lethrinid species caught by small and medium hooks suggests that these hook sizes
are causing recruitment and growth overfishing. Based on the results from this study,
large hooks which captured low number of individuals below Lm and Lopt and
resulted in higher CPUE should be trialed for use through gear modification to ensure
the protection of the highly overexploited and vulnerable lethrinid species for
sustainability in the fishery. Longer term studies covering larger fishing areas and
depth distribution of target species are needed to develop comprehensive
recommendations for the sustainable management of small-scale hook and line
fishery in coastal Kenya. | en_US |
