Abstract The Balance Balanus albicostatus is the dominant species of fouling organism in Kaohsiung Port. In different harbor district environments In Kaohsiung Port, one can discriminate the population of B. albicostatus into three different groups¡Gthe estuary area of Love River, the outer harbor area, and the harbor area. The variation of estuary area¡¦s (Jhongjheng Bridge Station on Love River) population is the highest with the averaged survival rate of 53.8¡Ó21.7%. The population in the harbor area (The First Harbor Mouth station) is more stable with the averaged survival rate of 62.5¡Ó8.1%. The composition of population in the eliminated area in all stations after one year is similar to the previous one. It is suggested that barnacle population in Kaohsiung port can recover from environmental disturbance throughout larval recruitment within a year. Based on the results from the growth experiment of the settled barnacle¡¦s larvae, it was indicated that the growth and survival rate of the settled larvae was least affected by the recruitment of any kinds of settled larvae including barnacle itself. To understand the influence of environmental factors on the hatching of egg and development of larvae, we cultivated the larvae of B. albicostatus under the control of temperatures and salinities in the laboratory. The hatching rate of egg and times required for larvae to metamorphosis at each stage is the shortest under the condition of high temperature and high salinity. The larvae can metamorphose into cyprid in five days after hatching at the high temperature (35¢J), while it is prolonged to 19 days after hatching under the low temperature (15¢J) and low salinity (22 psu). The settlement rate of cyprids is better under high salinity (33 psu). To understand the effects of biofilm on settlement of cyprids, the biofilms are cultured under the conditions of the non-filtered, 80£gm, 20£gm, and 1£gm filtered seawater. When the biofilms have grown for 5 days, the settlement rate of cyprids on the biofilm cultured by the filtered seawater is higher than those on the non-filtered biofilms and alcohol-sterilized ones. At the day 12, the 1£gm filtered treatments had a greatest quantity of settled larvae while the number of settled cyprids in the other treatments decreased. The number of settled cyprids on panels with biofilms cultured for 15 days in non-filtered seawater and the one with biofilms fallen off for more than 75% of the total area did not significantly differ from the one with biofilms cultured in the seawater filtered with the 1£gm mesh. This showed that biofilms cultured under different filtered conditions affect the settlement of cyprids over time. It is concluded that the population of barnacle Balanus albicostatus, based on survival rate and growth, can be grouped into three different groups in the Kaohsiung Port. From the laboratory experiments, it is showed that the type of biofilm and the aging processes over time can affect the settlements of cyprids. It therefore suggested that the larval recruitments of the barnacle B. albicostatus can be affected by the types of biofilm on the different substrates, and consequently the larval recruitments in the different environmental conditions in Kaohsiung Port.