Structural Complexity and Biomass of Arid Zone Mangroves in the Southwestern Gulf of California: Key Factors That Influence Fish Assemblages

Arid zone mangroves of the southwestern Gulf of California provide ecosystem services because of their habitat heterogeneity, structure, and functions, which are important for the formation of fish assemblages. Structure, litterfall production, and leaf decomposition in three mangrove communities located at La Paz Bay, Mexico, were analyzed. Litterfall production was found to be within the range reported for the region. Leaf decomposition rate was similar between communities and species. The structural complexity and biomass of mangroves were inversely correlated with fish size, suggesting that they are key features, providing shelter and nursery for fish assemblages. Laguncularia racemosa appears to play an important role in providing greater habitat heterogeneity within mangroves, favoring fish species richness. Avicennia germinans is the most important mangrove species in the region, having the highest leaf decomposition rate, thus providing an important input of carbon to food webs and potentially stimulating fish biomass. Thus, mangroves with lower structural complexity and higher dominance of A. germinans likely have a higher potential for artisanal fisheries in the southwestern Gulf of California.