112－113年度的藻礁生態調查主要是針對桃園市三個主要藻礁海域的六個測站：觀新藻礁三個測站（永安、永興、保生）、大潭藻礁二個測站（G1、G2）及白玉藻礁一個測站，進行8季的殼狀珊瑚藻多樣性及豐富度季節性變化的生態調查以及新竹縣新豐藻礁2次調查的成果報告。調查結果顯示，桃園藻礁海域8季調查共計發現殼狀珊瑚29種藻種，在六個測站中以大潭藻礁海域的G2測站最高（18種），其餘依次為觀新藻礁海域的保生測站（17種）、白玉測站（17種）、永安測站（16種）及永興測站（16種），而以大潭藻礁區的G1測站最低（12種）。桃園藻礁海域殼狀珊瑚藻8季調查的藻種數季節變化以112年1/2月（20種）藻種多樣性最高，其他6季的調查季節間差異不明顯（15種 ~ 18種），而以113年9月最低（11種）。全年可見（=四季皆有出現）的殼狀珊瑚藻有15個藻種，其中，有2種藻種為藻種紀錄百分比在20%以上，分別為哈維石藻sp. 1（22.7%）與孢石藻sp. 1（20.0%）。此外，季節性特定藻種有9種，包含僅發現於冬季（調查月份：1/2月）的石枝藻sp. 1、膨石藻sp. 1、膨石藻sp. 5；僅發現於春季（調查月份：3/4月）的北臺灣殼葉藻、孢石藻sp. 2；僅發現於夏季（調查月份：7月）的似綿藻sp. 1、哈維石藻sp. 5、道森氏藻sp. 4、道森氏藻sp. 5。
      桃園藻礁海域六個測站的殼狀珊瑚藻覆蓋率季節性變化在不同測站及不同月份皆有明顯差異。潮間帶上半部殼狀珊瑚藻覆蓋率以夏季（調查月份：7月）明顯低於其他季節。潮間帶下半部殼狀珊瑚藻覆蓋率以冬季（調查月份：1/2月）明顯高於其它季節，而殼狀珊瑚藻覆蓋率在春季（調查月份：3/4月）則明顯高於夏季（調查月份：7月）。G1測站固定框的殼狀珊瑚藻平均覆蓋率調查結果顯示潮間帶上半部北側的平均覆蓋率在8季間有明顯差異，而中側與南側的平均覆蓋率在8季間則無明顯差異。然而，潮間帶下半部中側與南側的殼狀珊瑚藻覆蓋率在不同季節間有明顯差異。
      新竹縣新豐藻礁海域兩年二次（112年3月與113年3月）共發現7種具造礁能力的殼狀珊瑚藻，而與112–113年桃園藻礁海域8季調查發現的29種殼狀珊瑚藻藻種相比，有2種道森氏藻僅記錄於新豐藻礁海域，其他5種殼狀珊瑚藻在桃園藻礁海域亦有紀錄。
      藻礁生態調查成果分析與比較海保署與中油監測計畫對桃園藻礁殼狀珊瑚藻的調查，綜合自108年3月~113年4月共19個季次的資料。統計結果顯示隨著每季次調查樣框數的增加，藻種數有增高趨勢。整體而言，桃園藻礁海域藻種多樣性調查在兩個計畫分別的調查結果中無明顯差異。在殼狀珊瑚藻覆蓋率的季節變化方面，海保署調查計畫、中油監測計畫與兩個計畫整合分析的三組數據皆顯示桃園藻礁殼狀珊瑚藻覆蓋率具有明顯的季節變化，以春季（3月—5月）平均覆蓋率較高，而夏季（6月—8月）時平均覆蓋率最低。

Abstract
The ecological survey of algal reefs conducted from 2023 to 2024 primarily focused on six stations across three major algal reef areas in Taoyuan City. This included three stations in the Guanxin algal reefs (Yongan, Yongxing, and Baosheng), two stations in the Datan algal reefs (G1 and G2), and one station in the Baiyu algal reefs. In total, eight seasons of surveys were carried out to examine the seasonal changes in the species diversity and abundance of crustose coralline algae (CCA). In addition, the survey included findings from the CCA ecological survey at the Xinfeng algal reefs in Hsinchu County. The results revealed that 29 species of CCA were identified in the Taoyuan algal reefs. Among the six sampling stations, the G2 station in the Datan algal reef area exhibited the highest species diversity with 18 species. The Baosheng station in the Guanxin algal reefs and the Baiyu station both recorded 17 species each, and 16 species from the Yongan and Yongxing stations. In contrast, the G1 station in the Datan algal reef area recorded the lowest number of species, with only 12. In terms of seasonal variations in CCA species diversity, the highest richness was observed in January and February 2023 (during the winter season), with 20 species being recorded. Throughout the other seasons, however, changes in CCA species diversity were less pronounced, ranging from 15 to 18 species. The lowest diversity of CCA species was observed in September 2013, during the autumn season, with only 11 species identified. Throughout the year, a total of 15 CCA species were recorded, appearing in all seasons. Among these, 2 CCA species had occurrence frequencies exceeding 20%, specifically Harveylithon sp. 1 (22.7%) and Sporolithon sp. 1 (20.0%). Further, 9 CCA species were only present in certain seasons. Within this group, Lithothamnion sp. 1, Phymatolithon sp. 1, and Phymatolithon sp. 5 were exclusively found in winter, while Crustaphytum taiwani-boreale appeared only in spring. Moreover, Spongites sp. 1, Harveylithon sp. 5, Dawsoniolithon sp. 4, and Dawsoniolithon sp. 5 were solely present in the summer.
Seasonal changes in the CCA coverage at the six sampling stations in the Taoyuan algal reefs varied in different stations and seasons. In the upper intertidal zones, the CCA coverages were significantly lower in summer (July) than in the other seasons. On the other hand, the CCA coverages in the lower intertidal zones were much higher in winter (January/February) than in the other seasons. In other seasons, the CCA coverage in spring (March/April) was significantly higher than that in summer (July). Regarding the mean CCA coverages in the fixed quadrats at the upper intertidal zone of the G1 station, the mean coverages at the north side of the G1 station varied significantly in different seasons; however, the mean coverages at the middle and south sides showed no apparent differences among different seasons. In contrast, the mean coverages at the middle and south sides of the lower intertidal zone of the G1 station varied significantly in different seasons.
From March 2023 to March 2024, 7 CCA species were identified in the Xinfeng algal reef area of Hsinchu County. In particular, 2 species of Dawsoniolithon were only found in Xinfeng algal reefs, but the other 5 species were also recorded in the Taoyuan algal reefs. In comparison, the species diversity in the Xinfeng algal reefs (7 spp.) was much lower than that found in the Taoyuan algal reefs (29 spp.). This situation might be due to differences in habitat complexity and sedimentation levels, which require further investigation.
When comparing the investigation results from this study and the Chinese Petroleum Corporation in terms of the CCA species diversity and coverages for 19 seasons, there was a tendency to identify more CCA species if more quadrats were investigated. Overall, the CCA species numbers revealed in this study were not significantly different from those identified by the Chinese Petroleum Corporation. In terms of seasonal changes in the CCA coverage, three sets of data from this study, the Chinese Petroleum Corporation, and the integrated data derived from the two different research groups all indicated that the CCA coverages varied significantly in different seasons. Generally speaking, the CCA mean coverage was much higher in spring (March - May) but was the lowest in summer (June - August).