The synergistic development of industries in aquapelago faces a dual dilemma characterized by the interaction of multiple stressors and insufficient analysis of synergistic factor mechanisms. Deconstructing the configuration effects of land-sea elements from the perspective of household adaptation has become a potential pathway to explore the mechanisms of land-sea industrial synergy. Guided by the integrated land and sea management theory, this study selects Dongtou District in Wenzhou City of Zhejiang Province, a typical island aquaculture base, as the research case. Employing a mixed-method approach combining grounded theory and fuzzy-set Qualitative Comparative Analysis (fsQCA), it reveals the driving logic of household adaptation behaviors and its factors on industrial synergy. The findings demonstrate: ① High temperatures, seawater pollution, labor shortage, land use conflicts and market fluctuations constitute the primary pressures on marine aquaculture around islands, with spatial effects exhibiting superimposed sensitivity characteristics at land-sea interfaces. ② The transition to intensive aquaculture in coastal zones fosters mutual feedback through industrial chain expansion, while the shift toward green aquaculture establishes reciprocal feedback via integrated fishery-tourism development. Household adaptation strategies actively drive these coupled feedback mechanisms. Attention should be given to industrial chain transmission issues and the livelihood transition challenges faced by small-to-medium-scale households. ③ The aquapelago achieves scaled intensification of aquaculture through the synergistic configuration of factors including stable tenure rights, scale transition, technology integration, and policy reinforcement, while driving industrial structure optimization via the aligned configuration of green aquaculture practices, technical support systems, and farmer endorsement mechanisms. To enhance synergy between industry structural adjustment and sustainable marine utilization, measures should enhance three-dimensional utilization of aquapelago, develop sustainable knowledge systems about marine functional zones, and leverage industry leaders to bridge land-sea spatial function. This research offers novel insights into the coordinated development of traditional island industrial improving, and intensive marine utilization under the land-sea coordination framework.