Mangrove use by sharks and rays: a review

Abstract

A wide variety of species depend on mangroves, making them essential habitats in tropical and subtropical regions. While the function of mangrove habitat is well studied for taxa such as teleost fishes, limited attention has been directed towards their value for elasmobranchs. Here, we review the available literature on how and why elasmobranchs use mangrove habitats based on 65 papers identified through literature searches. The use of mangrove habitat as nursery areas in combination with other coastal habitats has been well examined, although we found taxonomic and regional biases in research. Additionally, mangrove habitats are considered to offer elasmobranchs feeding opportunities and refuge from predators, yet such functions have rarely been tested. In particular, the ecological role of elasmobranchs within mangrove habitats is poorly known; as it is difficult to study their behaviour in complex mangroves, their feeding ecology is understudied as are trophic linkages between mangrove and adjacent ecosystems. For a greater understanding of the association between mangroves and elasmobranchs, direct observations of elasmobranch behaviour in mangrove habitats are needed. Given global concern regarding mangrove loss, understanding how this affects elasmobranch populations will require long-term studies, particularly in those regions where losses are greatest. We identify 8 key research questions that will help improve this understanding.