Distribution gradients of ichthyoplankton in an East African mangrove creek

• Published in: Estuarine, coastal and shelf science Vol. 26; no. 6; pp. 669 - 677
• Main Authors: Little, M.C., Reay, P.J., Grove, S.J.
• Format: Journal Article
• Language: English
• Published: London Elsevier Ltd 01.06.1988; Elsevier
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Biological and medical sciences; Brackish water ecosystems; Fundamental and applied biological sciences. Psychology; gradient; ichthyoplankton surveys; Indian Ocean West; Kenya Coast; mangrove swamps; nursery grounds; Synecology; ichthyoplankton surveys; Kenya Coast; Indian Ocean West; nursery grounds; mangrove swamps; gradient; Brackish water environment; Vertebrata; Spatial distribution; Larva; Egg; Mangrove; Pisces; Africa; Nursery (animal); Kenya; Ecological abundance; Ichthyoplankton
• ISSN: 0272-7714; 1096-0015
• DOI: 10.1016/0272-7714(88)90042-X

As part of an investigation into the role of East African mangrove creeks as fish spawning and nursery areas, nocturnal ichthyoplankton sampling was carried out at five stations in Tudor Creek, Mombasa, Kenya, from September to November 1985. Throughout the creek, the salinity was close to that of seawater at about 35‰, but from the mouth to the upper creek there were gradients of increasing temperature and turbidity, and decreasing depth and dissolved oxygen concentration. Pelagic eggs and larvae of fish considered to be creek residents and creek non-residents were distinguished. Gradients of decreasing egg and larval abundance (particularly of non-residents), and of decreasing diversity of recognized types, were apparent from the mouth towards the upper creek. Such a distribution suggests that the mangrove system is not an important spawning or development area for the earliest life-history stages of non-resident species. The existence of the gradients also has implications both for sampling at fixed stations in tidal waters, and for investigating the existence of circatidal and semilunar spawning cycles in fish.