Habitat mosaics of mangroves and reefs support fisheries sustainability for Traditional Owners

Effective marine conservation planning that supports long-term food security for Indigenous peoples requires a clear understanding of how fish populations use coastal seascapes and interact with local fisheries. Mangroves provide sheltered, accessible fishing grounds that support abundant culturally and commercially important fish. Their ecological connectivity with adjacent reefs, shaped by local tidal regimes, determines how fish use these habitats for food and shelter. We investigated these dynamics in the Bardi Jawi Indigenous Protected Area in the Kimberley region of northwest Australia, an area exposed to extreme tidal ranges (∼12 m). Fish populations were sampled using baited video surveys at mangrove and reef habitats over five years. Satellite-derived habitat models quantified habitat metrics (e.g. area) at local scales. Data were combined to quantify fish population metrics and their relationship to habitat and other environmental variables. Species richness and total fish abundance were higher on reefs, particularly in areas with higher water clarity and greater structural complexity. However, for ten culturally important fisheries species, abundance and biomass were similar in mangrove and reefs and positively associated with the number of available habitat patches regardless of type. Notably, mangroves supported a higher proportion of larger individuals in four of the ten cultural fisheries targets. Bardi Jawi Traditional Ecological Knowledge has long recognised the importance of mangrove-reef connectivity for sustaining fisheries and has informed the design of local spatial protection boundaries that include both habitats. Conservation strategies that integrate knowledge systems to protect mangrove-reef mosaics are essential for sustaining fish populations across coastal seascapes. • Ecological data reinforce TEK guiding marine park zoning across habitat mosaics. • Cultural fisheries targets use mangrove–reef seascapes and respond to complexity. • Species richness and abundance peaked in clear, complex reef habitats. • Mangroves hosted larger fish for four of ten cultural fisheries targets. • Habitat diversity is essential for food security of Indigenous coastal communities.