For the first time, an accurate quantitative survey of macrofouling in the underground water intake tunnel of the Vladivostok combined heat and power plant (CHP-2) was carried out using laser technologies to develop a strategy for protecting the seawater cooling system from biological damage. In the tunnel biofouling, 91 species of invertebrates belonging to various taxonomic groups were found. The maximum development of macrofouling was established in the lower part of the water intake tunnel with the dominance of the Pacific mussel Mytilus trossulus. In the fouling of the tunnel upper part, a quantitative predominance of attached polychaete worms of the genus Hydroides was noted. For the concrete sections of the tunnel, the maximum values of the mass of silt biodeposits were recorded, while the steel sections were characterized by calcareous biodeposits. It was noted that the total raw biomass of tunnel macrofouling was 35-50 times greater than the biomass of macrofouling organisms. This difference indicates the predominant role of meioenthos and microperiphyton organisms in the formation of the fouling community. The differences in the species richness and quantitative indicators of fouling of the tunnel in 2015 compared to 2001 are shown. Thus, the macrofouling estimation of the water intake tunnel of the Vladivostok CHP-2 allows concluding about the need for a comprehensive strategy for protecting the cooling system from marine fouling. Such a strategy is assumed to combine physical methods and other technological methods.