Biofouling Community Dynamics on Nylon and Polyethylene Aquaculture Nets in the North Yellow Sea: Colonization Patterns and Mytilus edulis Mechanical Properties

A hanging net test was conducted from May to November 2022 on Takifugu rubripes culture nets at Wang Jia Island in the North Yellow Sea, China. The study identified 21 species of fouling organisms, with Mytilus edulis emerging as the dominant fouling organism colonizing aquaculture net cages. Coverage rates varied temporally, with water depth, and by net material, exhibiting a unimodal pattern that peaked between June and October (38.46–98.45%). At different depths, the coverage rates were highest at −0.5 m (75.14% to 98.65%). Additionally, nets made of nylon (29.41% to 98.65%) had an average coverage rate 8.2% higher than those made of PE mesh (26.34% to 90.45%). To assess the growth and mechanical properties of M. edulis, we analyzed its morphological relationships. A strong positive linear correlation was observed between shell length, width, and thickness, while body weight followed a power function relationship with shell dimensions. Growth curve analysis indicated that M. edulis reached maturity in late August. Compression tests revealed a defined yield point, with crack propagation varying by force direction. The maximum compressive force occurred in the thickness direction (195.95 N), with resistance increasing progressively from length to width to thickness. These findings elucidate biofouling dynamics on aquaculture nets and support the development of improved antifouling technologies.