臺灣西南部河口域大型底棲生物相的研究

Studies on the Benthic Macrofauna in the Estuaries of Southwestern Taiwan

徐崇仁(Chung-Zen Shyu) ； 吳全橙(Chuan-Chern Wu)

《臺灣水產學會刊》 12卷1期 (1985/06) Pp. 21-35

https://doi.org/10.29822/JFST.198506.0001

摘要

本研究的目的在調查北港溪及朴子溪河口域及其鄰近海區之底棲生物相及其底質、羣聚分佈以綜合評估各區環境特性的時、空變化。
調查時期在1984年6月及11月二航次，共設十一測站，使用彈簧壓力式1／20平方公尺之史氏採泥器採集海底沉積物及底棲生物，調查底質之粒度分佈、有機物含量（强熱減量）分佈、底棲生物之生物量、種類及羣聚分佈等。
1.北港溪口及朴子溪口底質較細有機物含量較多，外傘頂洲外側底質較粗，有機物含量較少，而內側水域似有愈往深處底質愈細，有機物含量愈多的傾向。
2.本研究中所採集生物以0.5 mm以上而濕重量小於1g者爲對象，卽一般所謂小型macrobenthos。其生物量不論6月或11月之結果顯示本海區概屬貧營養區。且其分佈在布袋外海以6月間較多，而11月則減少。反之在較淺的朴子溪口至外傘頂洲間則以11月較多而6月間減少。外傘頂洲外側之生物量則概屬少量。
3.本區出現之底棲生物種類數共約73種以上，選定二十種多毛類及二枚貝類之優勢種及標徵種進行了6月、11月和6月及11月合計各測站生物相的類似度（Kimoto指數）及羣聚分析（Mountford平均連結法）。
4.分析結果顯示，羣聚分佈略與沿岸平行，主要取決於受沿岸海域水質影響之程度，同時亦多少受到深度及底質變化的影響。而其季節性的變化導致羣聚內的局部變異與水質變化之關係尤爲顯見。
由出現種類之指標性顯示，沿岸之羣聚主要爲中內灣性者，向外有逐漸減弱的傾向，一般强內灣性的種類並未出現，顯示本海域是一個較開放而水交換尙佳的海域，故有機污染在大部份時期較不顯見。

並列摘要

In order to assess the temporal and spatial variation of marine environment, macrobenthic fauna and their bottom environment in the estuaries and adjacent waters of Pei-Kan and Po-Tzu rivers in the southeastern Taiwan was investigated . Benthic organisms and sediments were collected from 11 stations with l/20 m^2 Smith-Mclntyre spring-loaded grab sampler during June and November, 1984. Then, grain size distribution, organic content (by ignition loss) of sediments, biomass, species and their distribution were studied.
The sediment at the estuaries of Pei-Kan river and Po-Tzu river is fine and with relatively high organic content, while the area around sandy shoal (Wae-San-Tin-Chou) is coarser and with less organic content. The inner embayment has an inclination of finer sediment with higher organic content toward deeper water. Biomass of smaller macrobenthos (＞0.5 mm, ＜1g) distributed in these 11 stations both in June and November indicated that the studied area can be catagorized as oligotrophic area. The biomass of deeper waters down south was more in June and less in Nevember, and was constantly less around sandy shoal.
The species number of benthic organisms sampled was more than 73 species. Data of 20 domina nt or characteristic species was used for analyzing the similarity among 11 stations by Kimoto, 5 index and clustering analysis was carried out with Mountford’s method.
The distribution of communities were parallel with shore line. The dominant or characteristic species in communities indicated that the more polluting-tolerable (stronger degree of embayment) communities was distributed neaer the estuaries. It is suggested that the distribution of benthic fauna was mainly influenced by polluted water, depth and type of sediment. In addition, the community structures were also modified by seasonal variation of environment. It is Concluded that the studied area was not significantly organic-polluted in most time of the year inbicated by adsence of strong polluting-tolerable species. It may be attriduted to the semi-opened geography and fluent water change of this area with outer waters.