Rapid multiple method assessment reveals the effects of tidal restriction and restoration on fish and crustacean communities in a California estuary

Saltmarshes are one of the most valuable ecosystems on the planet, providing shoreline protection, carbon storage, and nursery habitat, but face significant pressure from human activity and sea level rise. Saltmarsh restoration strategies aim to recover ecological function and provide resilience to rising seas, yet their effects on mobile creek fauna (fish and decapod crustaceans) remain understudied on the North American Pacific coast. Researchers frequently seek rapid, cost-effective tools for studying these communities as they are effective indicators of marsh condition. This study assessed the ecological success of saltmarsh restoration and provides insight for future monitoring efforts. Assemblages were compared across one tidally restricted marsh, one sediment-addition restored marsh and two natural reference marshes in Elkhorn Slough, California using three different, but complementary methods over a two-month rapid assessment. In total, we detected 4,833 individuals from 14 species. The restricted marsh supported the lowest abundance, smallest topsmelt ( Atherinops affinis ), and fewer and smaller transient species, indicating reduced nursery function. In contrast, the restored marsh closely resembled the adjacent natural marsh in community composition and ecological attributes present, such as trophic roles and residency patterns, and supported the highest native richness. Natural sites also differed from one another, highlighting the need for multiple reference sites in restoration assessments. Minnow traps provided consistent species detection and replication, seines captured the highest numbers of transient fish, and underwater videos detected large, elusive species. Results demonstrate that mobile creek fauna can rapidly re-establish after sediment-addition and that combining rapid sampling methods enhances understanding of ecological functions.