After starting life out as an environmental chemist (joined to a lab bench) Christina traveled home to Kenya to experience the real world. She spent two years working on fisheries related issues with Dr Tim McClanahan. In this time she was responsible for the ongoing collection of fisheries statistics as well as the analysis of this ten year data set. She was also involved more broadly in fisheries issues, liaising with the Fisheries Department and Ministry of Agriculture and Livestock. This work led her to a Masters degree at Newcastle University where her research took an ecological economics focus, assessing coral-reef social ecological systems. Prior to joining the Centre as a PhD student, Christina was involved in mapping the extent of interdisciplinary research in the Environmental Sciences with Prof Polunin. Supervised by Terry Hughes, Bob Pressey and Josh Cinner, her current research on ecosystem services has two key focuses: 1) understanding the links between biodiversity change and ecosystem service provision and 2) improving the integration of cultural services into planning for conservation.
In this talk I will present results from a ten year time series, of an ongoing coral reef fisheries monitoring program, along a 75km stretch of Kenya’s most populated coastline. We examine trends associated with fishing intensity, increased gear, and area based management, to test: 1) Malthusian predictions in coral reef fish communities; 2) susceptibility of life history traits; and 3) species specific levels of exploitation. Results indicate 1) as predicted by Malthusian scenarios; catch per unit effort (CPUE), mean trophic level, functional diversity of fished taxa, and diversity of gear declined; while total annual catch and catch variability increased along the fishing pressure gradient. We found that sites within 5 km of the enforced closure showed significantly lower total catch and CPUE, but increased yield stability and trophic level of catch than predicted by regression models normalized for fishing effort. Sites with established gear management exhibited increased total catch and CPUE. 2) Meeting predictions inferred from susceptible life history traits; increased management led to lower consumption rates, higher trophic levels, lengths at maturity and optimum yield. However, contrary to predictions intrinsic rates of growth and natural mortality increased, whilst age at maturity, life span and generation time were reduced. 3) Length frequency distributions, analysed using fish base and the linearised length converted catch curve method, show Leptoscarus vaigensis to recruit to the fishery close to Lmat whilst Siganus sutor and Lethrinus lentjan show clear evidence of growth over fishing. Beachseine caught the largest numbers of these species, over 95% of which are below Lmat. In addition, exploitation rates for all three species are considerably higher than reported elsewhere in the literature. A strong interaction between closure and gear management indicates that for closures to be effective at increasing catch, there must be simultaneous efforts at gear management around the periphery of the closures. Further, open-access fishing grounds can benefit from management in adjacent fishing grounds. However, management in Kenya is still insufficient at addressing species specific considerations which remain dependent on spill over, from across the reef crest, for replenishment.