Population dynamics of Aurelia aurita (Scyphozoa) from an isolated brackish lake, with particular reference to sexual reproduction
Population dynamics of Aurelia aurita (Scyphozoa) from an isolated brackish lake, with particular reference to sexual reproduction
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DOI：
10.1093/plankt/18.6.987
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发表时间：
1996-06
影响因子：
2.1
通讯作者：
C. Lucas
中科院分区：
文献类型：
--
作者：
C. Lucas
在英国马海湖一个孤立的、浅的、半咸淡的人造水体中，研究了scyphomedusa Aure- lia aurita的年丰度、生长和有性繁殖周期。12月开始出现痉挛，到6月有不同数量的赤虫出现，表明有7个月几乎连续的招募期。马海湖黄颡鱼种群密度大，5月中旬高峰丰度为24.9 rrr3。从3月到1月，水柱中有美杜莎水母（直径10毫米）。9月下旬最大钟径为105毫米。然而，水母的生长非常差（G值在12个月期间的-0.03至0.07天之间），月平均钟形直径通常<50毫米。在一年的大部分时间里，丰富的aurita种群很可能受到数量和物种匮乏的中浮游动物群落的严重食物限制，这些中浮游动物群落以类calanoid桡足类Acartia margalefi和Acartia lonsa为主。然而，非常小的水母A.aurita medusae仍然能够达到性成熟和繁殖。在5月和6月首次观察到携带受精卵和浮藻幼虫的成熟雌水母，尽管浮藻幼虫的主要生产期是9 - 12月。11月雌虫全部成熟，最小的铃径为19-20毫米。在马海湖和附近的高产河口南安普顿水域，浮藻幼虫产量随湿重呈线性增长，尽管与来自南安普顿水域的较大的medusae相比，马海湖的繁殖产量较低。马海湖小黄花种群特征对环境条件的响应表现出可塑性，繁殖力和大小成熟度均随季节变化。当食物充足时，美杜莎似乎将可用的食物资源划分为躯体生长或食物匮乏时的生殖努力。
The annual cycle of abundance, growth and sexual reproduction of the scyphomedusa Aure- lia aurita was examined over a 12 month period in an isolated, shallow, brackish, man-made body of water: Horsea Lake, England. Strobilation started in December and ephyrae were present through June in varying numbers, suggesting a 7 month period of near-continuous recruitment. Horsea Lake has a dense A.aunia population, with the peak abundance of 24.9 rrr3 occurring in mid-May. Medusae (>10 mm) were present in the water column from March through January. Maximum bell diameter of 105 mm was observed in late September. However, medusa growth was very poor (G ranged between -0.03 and 0.07 day' over a 12 month period), and monthly mean bell diameters were typically <50 mm. For most of the year, the abundant A.aurita population was most likely severely food limited as a result of a numerically and species-poor mesozooplankton community dominated by the calanoid copepods Acartia margalefi and Acartia lonsa. Nevertheless, the very small A.aurita medusae were still able to attain sexual maturity and reproduce. Ripe female medusae carrying fertilized eggs and planula larvae were first observed in May and June, although the main period of planula larva production was Septem- ber-December. In November, all females were ripe, the smallest being 19-20 mm bell diameter. At both Horsea Lake and a nearby productive estuary, Southampton Water, planula larva production increased linearly with wet weight, although compared with the larger A.aurita medusae from South- ampton Water, reproductive output at Horsea Lake was low. Aurelia aurita in Horsea Lake showed plasticity in its population characteristics in response to environmental conditions, with both fecundity and size to maturity varying on a seasonal basis. Medusae appeared to partition the available food resources into either somatic growth when food was abundant or reproductive effort when food was scarce.