Historical use of coastal wetlands by small-scale fisheries in the Northern Gulf of California

Abstract

Coastal wetlands are rich and productive ecosystems that historically have been used by small-scale fisheries due to their role as refuges, feeding, and nursery habitats for commercial target species. We used wetland resource users' Local Ecological Knowledge to document historical patterns of commercial species abundance, areas of fishing importance, trophic level, and species richness and composition in coastal wetlands in the Northern Gulf of California, Mexico. We also reconstructed the environmental history of coastal wetlands in this region from bibliographic sources and photographic records, to document impacts that could have affected coastal fisheries. We found a consistent downward trend in target species abundance; the decrease was perceived as more pronounced by fishers that began fishing in or prior to the 1950's, pointing to shifting baselines, the failure for resource users to recognize environmental change and accept degraded states as normal. Areas of fishing importance within coastal wetlands also decreased through time. Trophic level of catch showed no distinct pattern across wetland sites or time. Perceived species richness and composition increased with wetland size. Our analysis of the small-scale use of coastal wetlands in the Northern Gulf is relevant to food security and can provide insight into how local populations adapt to depleted coastal food webs.