Many tropical countries are data-poor when it comes to fisheries or information on marine megafauna. To fill the data gaps and support precautionary management measures, we have conducted socio-economic assessments of a range of small-scale fisheries including on reef-associated fish, sharks, Goliath grouper and deep-water fishes. Depending on the targeted group and information needed, the surveys are shaped as pre/post, retrospective, online surveys or catch reconstructions. Results are triangulated with fisheries-independent field surveys and, where possible, market surveys to better quantify the diversity, distribution, size and demography of species landed as well as seasonality of catches and market prices. Since consumption of marine resources is not the only driver related to the value of marine wildlife, we also conduct surveys to assess the status of sawfish and dive tourism generated by whale sharks and reef sharks. Results have been used to better tailor management and conservation efforts, including legislation for reef fish spawning aggregations, MPA designation, protection of coastal and reef-associated sharks, species protection for whale sharks (Rhincodon typus) and nurse sharks (Ginglymostoma cirratum), and proposed size limits for the Goliath grouper (Epinephelus itajara) fishery.