Seagrass beds provide critical nursery habitats and spawning grounds for new generations of fish. The habitats are under threat from human activities and climate change, and with that, an important ocean service is lost that limits fish production. The present study investigates patterns in the larval occurrence and abundance in seagrass meadows at two locations with varying degrees of seagrass fragmentation. Monthly ichthyoplankton sampling was conducted during the northeast monsoon (NEM) and southeast monsoon (SEM) seasons in 2019 and 2020. A total of 42 larval fish families belonging to 37 genera and 21 species were identified. Dominant families were Labridae (29.5%), Blenniidae (28.7%), Gobiidae (26.0%), Engraulidae (23.3%) and Scaridae (22.3%). Canonical Correspondence Analysis and regression analysis revealed water temperature, dissolved oxygen and pH as the most important abiotic variables driving taxonomic composition of larval assemblages, while zooplankton and chlorophyll-a were the most important biotic factors. Fish larvae were more abundant in healthy seagrass habitats as compared to degraded ones. However, despite some loss in functionality, the degraded sites equally played a role in supporting some species, including Gobiidae and Blenniidae. Seasonality influenced larval abundance at the two sites, with a peak in mean abundance coinciding with the NEM season. Interannual variability in fish larval abundance was observed at both sites, indicating that factors controlling larval production varied between the years. This study demonstrates the important role of seagrass meadows in the replenishment of fish stocks and supportive evidence for their management and conservation.

Seagrass are important marine habitats that function as nursery grounds for juvenile fish. Human activities and other natural factors have contributed to their decline, and this has compromised their role as nurseries, specifically in non-continuous patchy seagrass beds. In this study, juvenile fish abundance from tropical seagrass beds of Watamu were examined, while testing the hypothesis that seagrass cover and seasonality influenced juvenile fish abundanceand diversity. Two sampling stations were identified, Watamu Blue Lagoon (WBL) and Watamu Beach (WB), based on seagrass cover, and were sampled for a period of 10 months that included two south-east monsoon (SEM) and two north-east monsoon (NEM) seasons. Monthly samples were collected by seining within the shallow seagrass habitats of WBL and WB. A total of 31 juvenile fish families were obtained, the dominant taxa being Lutjanidae and Siganidae. Seasonal and interannual variability in juvenile abundance was observed over the two years (p<0.05); year 1 recorded higher abundance than year 2, specifically during the SEM. In year 2 a higher mean abundance was recorded during the NEM when compared to the SEM. Chlorophyll a (p<0.05) and salinity (p<0.05) were found to significantly influence juvenile fish abundance.

Fish larviculture depends heavily on live feed availability, during the critical first-feeding stage. In Kenya, hatcheries commonly use phytoplankton or imported Artemia cysts as starter feeds, although locally produced Artemia is available. Hatchery operators’ reports on low larval survival when using imported Artemia prompted this study to compare growth performance and survival of Clarias gariepinus larvae fed Kenyan-produced and imported Artemia. A 21-day feeding trial was conducted using twelve glass aquaria (60 × 30 × 30 cm), each containing 30 L of water. A total of 5,400 larvae (mean initial weight 1.83 mg; mean initial length 6.09 mm) were stocked at 15 larvae L−1. Three dietary treatments replicated four times were tested: Kenyan-produced Artemia (KMFRI), Great Salt Lake Artemia (GSL) and Shell-Free Artemia (SFA). Larvae were fed exclusively on Artemia from day 2 to day 8, co-fed with Artemia and dry feed from day 9 to day 11 and thereafter fed exclusively on dry starter feed until day 21. No significant differences (p>0.05) were observed in mean total length among treatments throughout the trial. Body weight differed significantly (p<0.05) on day 7, SFA-fed larvae showing superior growth. Survival was also significantly higher (p<0.05) in SFA-fed larvae compared to encapsulated treatments. Kenyan-produced Artemia performed comparably to imported GSL Artemia despite lower crude protein content. Findings indicate that seven days of live feeding are sufficient for efficient larval rearing of C. gariepinus and that locally produced Kenyan Artemia represent a cost-effective and biologically feasible alternative to imported Artemia in hatchery production systems.

Understanding juvenile fish distribution across habitat mosaics is essential for interpreting ecosystem connectivity and function. This study assessed seasonal variations in juvenile reef fish assemblages across a mangrove-seagrass-coral reef continuum in Shimoni, southern Kenya. Using a beach seine net, sampling during the Northeast Monsoon (NEM) and Southeast Monsoon (SEM) seasons, a total of 8,575 individuals representing 228 species and 52 families were recorded. Species richness and diversity (H') were highest in the coral associated site (n = 168; H' = 3.77), followed by the seagrass associated site (n = 132; H' = 3.69) and the mangrove associated site (n = 119; H' = 3.64). Two-way ANOVA and Kruskal-Wallis tests revealed significant differences in diversity and mean species richness, respectively across habitats, with post-hoc pairwise tests identifying the most pronounced differences between coral and mangrove sites. While 69 species were common to all three habitats, multivariate analysis demonstrated distinct species-habitat associations, particularly in the mangrove associated habitat, influenced by salinity and temperature. The Kolmogorov-Smirnoff test further confirmed differences in the trophic signatures of the assemblages between mangrove-coral and seagrass-coral interfaces. These findings underscore the importance of the coastal habitat mosaic in sustaining fish recruitment and population dynamics, highlighting the need for integrated seascape management in the Western Indian Ocean.