<b>Spatial and temporal variability in size structure and some reproductive traits of kawakawa and skipjack tuna in the Western Indian Ocean</b>

The artisanal fishery in the Western Indian Ocean (WIO) benefits from tuna species of great economic value, such as skipjack (<i>Katsuwonus pelamis</i>) and kawakawa <i>(Euthynnus affinnis</i>). These two species are highly targeted by fishers hence information on fish reproduction, such as size at maturity, is critical for informing management decisions. This study assessed the geographic variation in several reproductive traits of skipjack and kawakawa in the WIO using samples collected from artisanal tuna fishers in Kenya, Tanzania, and Mozambique, and recreational fishers in South Africa. Results revealed variations in the size structure of skipjack and kawakawa between countries, which may be attributed to gear selectivity because of gear type preferences by the fishers among other factors. The sex ratio of both skipjack and kawakawa landed was skewed towards males. Females and males skipjack matured at 42.0 and 47cm (FL) whilst females and males kawakawa matured at 44.0 and 45.3 cm (FL) respectively. The reproductive capability of both species was recorded throughout the year at all the study sites, but peaks were observed during Northeast Monsoon (NEM) season. Our findings reveal variations in some reproductive characteristics of skipjack and kawakawa between the WIO countries, highlighting the need for specific management strategies for each country within the region.