The mangrove forests as nursery habitats for the ichthyofauna of Mida Creek (Kenya, East Africa)

Abstract

This study investigated the presumed nursery function of mangroves for the ichthyofauna in East African swamp forests, Mida Creek. The species and size composition of the fish fauna and their trophic interactions were studied for five stations. Samples were collected during 5-6 consecutive days close to spring tide in mid-July 2011. Fish were caught using different types of passive fishing gear, such as large and small fyke nets, gill nets and, additionally, beach seines. All individuals were identified to species level, measured and preserved for further analyses. Stomach content analysis was applied to provide information about their diet. Stable isotope analysis was used to detect whether the source of primary production for the higher trophic levels is mangrove-related or not. A total of 27 fish species was recorded in a catch of 938 teleost specimens. Our analyses showed that a majority of fish belonged to the zoobenthivorous/omnivorous trophic mode, since they were partially feeding on invertebrates and on various other food sources. Two species (Sphyraena barracuda and Synodus variegatus) exhibited a mixed diet, with a piscivorous preference. Results concerning the population structure suggested that the fish community of Mida mainly consists of transient species. Juveniles were numerically more abundant in the whole Creek than adults. These findings support the hypothesis of a nursery function of the mangrove forests, Mida Creek.

Diet and trophic status of fish landed by tropical artisanal bait fishers, Mida creek Kenya

“…This requires further elaboration by examination of ontogenic shifts in species landed by bait fishermen. Gajdzik et al, (2014) describe the trophic interaction of fish caught using nets at the same study site (i.e. Mida creek) reporting a total of 27 species comparable to total number of species landed by all the baited gears reported here.…”

“…This study will evaluate the diet and trophic status of fish landed by bait fishermen using three types of bait at Mida creek, Kenya. consisting of mangrove forests, seagrass beds, sandflats, rocky outcrops and subtidal habitats (Gajdzik et al, 2014).…”

Morphometric and developmental characteristics of fish landed by artisanal bait fishers at the Mida Creek, Kenya

“…Similarity in fish morphometric index may be attributed to interconnectivity between mangrove forest, seagrass beds and coral reefs habitats utilized by the fish (Garrison et al, 2004;Gadjzik et al, 2014), that cancels out these apparent differences. Mangrove forests, apart from housing permanent residents, are also renowned for harboring transiting predatory and breeding adult fish (Krumme and SaintPaul, 2010;Gajdzik et al, 2014). Wambiji et al (2008) and also Agembe et al (2010) report higher condition factor of 0.9 to 1.2 for Siganids captured using basket trap and other gears, in the south coast of Kenya.…”

“…basket traps, weirs, fence traps), have been mentioned in literature. While the morphometrics of fish landed using nets by artisanal fishers along the Kenyan coast (Kaunda-Arara et al, 2003;Agembe et al, 2010 Gajdzik et al, 2014) and elsewhere, have been described, those landed by bait fishers (hook and trap fishers), have received less attention and hence the current study.…”

Comparison of isotopic turnover dynamics in two different muscles of a coral reef fish during the settlement phase

“…Carassou et al 2008, Frédérich et al 2009, Gajdzik et al 2014, the epaxial musculature is usually sampled for the isotopic analyses. To our best knowledge, no study has compared the ontogenetic dynamics of isotopic turnover from different muscles in a coral reef fish during the transition phase from the pelagic to the benthic environment.…”