“…The purpose of this Special Issue of Water is to study the responses of individuals, communities, and even marine ecosystems to anthropogenic activity and environmental stressors, for which five original papers have been collected (Table 1). In general, these papers, based on the background of human activities and environmental pressure, have studied the molecular responses of marine polychaetes (Sternaspis scutata) to polycyclic aromatic hydrocarbons (PAHs) [8], the spatial genetic structure and diversity of the large yellow croaker (Larichthys crocea) [9], the relationship between the eDNA concentration and the biomass of the fish Acanthopagrus latus [10], the potential influencing factors of the northward expansion of warm water Doliolida (Dolioleta gegenbauri) [11], and the assessment of the quality of the benthic habitat in the intertidal zone of an estuary [12]. To study the response characteristics of marine polychaetes to environmental pollutants, Yu et al [8] identified a new Cytochrome P450 (CYP) gene from Sternaspis sculata (marine polychaetes widely distributed across the coasts of the world).…”