Polyethylene fishing nets, widely used in marine fishing and aquaculture, have their color selection directly impacting fishing efficiency and closely related to the health of marine ecosystems. Different colored polyethylene fishing nets create a complex relationship between fishing effectiveness and ecological effects by altering fish visual perception, adjusting catch composition, and influencing microplastic pollution pathways.
Fish's ability to perceive net color is a core factor affecting fishing results. Mid-to-upper-level fish generally possess color perception abilities, distinguishing objects of different colors based on ambient light conditions. For example, light blue polyethylene fishing nets, similar in color to seawater, reduce fish alertness during bright daylight, making them easier to approach the net and thus increasing catch efficiency. Conversely, white fishing nets, with their strong contrast to the seawater background, are easily spotted and avoided by fish, leading to decreased catches. Transparent polyethylene fishing nets, due to their concealment, are a high-catch choice for gillnetting operations. It is noteworthy that fish color vision depends on light intensity; at night or in deep water, fish's color perception is significantly weakened, greatly reducing the impact of net color.
The color of fishing nets plays a differentiated role in selective fishing for different fish populations. Schooling fish such as sardines are sensitive to the coarse seams at the joints of the nets, which are easily identifiable due to movement and color contrast, leading to a lower catch rate in that area. Using light blue nets that match the seawater color reduces fish's perception of the net structure, thus improving the catch rate for these fish. Furthermore, adaptive adjustments to net color are crucial for fish in different habitats. For example, in bottom-dwelling fish operations, choosing nets that closely match the seabed color can reduce fish escape rates and optimize the fishing structure.
The choice of fishing net color must balance fishing efficiency with ecological protection needs. Although light blue nets offer high concealment under most lighting conditions, the dyes added during their production, if containing heavy metals, can cause long-term pollution to the marine environment during degradation. In contrast, while transparent nets reduce dye use, their high visibility may reduce catch efficiency, forcing fishermen to increase their workload and indirectly exacerbating marine ecological pressure. Therefore, developing environmentally friendly dyes or promoting the use of primary-colored polyethylene fishing nets has become an important direction for reducing ecological risks.
The contribution of fishing net color to marine microplastic pollution is potentially linked. Polyethylene materials gradually degrade into microplastic particles in the marine environment, and different colored fishing nets may affect the degradation rate due to differences in additives. For example, dark-colored fishing nets may contain more pigment additives, releasing more chemicals during degradation and exacerbating toxic effects on plankton and benthic organisms. Simultaneously, the color difference of microplastics affects their probability of being ingested by organisms; transparent or light-colored microplastics are more easily ingested by zooplankton, and thus passed to higher trophic levels through the food chain, threatening the health of marine ecosystems.
Fishing net color selection also involves ecological impacts at the non-visual perception level. The vibration noise of fishing nets under the action of water currents can interfere with the lateral line system of fish, and the synergistic effect of color and vibration may amplify this interference effect. Dark-colored fishing nets, due to their high heat absorption, experience increased surface temperature under sunlight, potentially altering local water temperature and affecting fish habitats. The superposition of these non-visual factors and color effects further complicates the mechanism by which fishing net color affects marine ecology. From a long-term ecological management perspective, the standardization and regulation of fishing net colors are crucial. International fisheries organizations are gradually promoting the establishment of a color-coding system for fishing gear, enabling rapid identification of gear types, operating areas, and ecological risks through unified color coding. For example, restricting the use of light blue fishing nets to specific ecologically sensitive areas, while prohibiting the use of highly visible nets in spawning grounds, can effectively reduce interference with fish reproduction. Simultaneously, promoting biodegradable polyethylene fishing net materials to reduce microplastic pollution has become a key measure for achieving sustainable fisheries development.
The color selection of polyethylene fishing nets is one of the core variables affecting fishing efficiency and marine ecology. Optimizing color design can improve catch efficiency while reducing disturbance to marine life and minimizing the risk of microplastic pollution. In the future, with the deepening of research in materials science and ecology, developing a fishing net color system that combines efficient fishing with ecological compatibility will become an important direction for promoting the green transformation of fisheries.
