. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. I960 1979 1973 February March April May June July Figure 1. The seasonal occurrence and characteristics of Cyanea medusae in the Niantic River estuary, 1973-1986. Solid triangles indicate sample dates. Sampling was less frequent, 1973-1979, and the pattern shown represents the average for those years. and exumbrellar epithelium, only the mesoglea remains. Even in an early deteriorated state, the medusae cannot feed (see below). Medusae, in one or another stage, occur for about 4 months each year before they disappear. The av
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. I960 1979 1973 February March April May June July Figure 1. The seasonal occurrence and characteristics of Cyanea medusae in the Niantic River estuary, 1973-1986. Solid triangles indicate sample dates. Sampling was less frequent, 1973-1979, and the pattern shown represents the average for those years. and exumbrellar epithelium, only the mesoglea remains. Even in an early deteriorated state, the medusae cannot feed (see below). Medusae, in one or another stage, occur for about 4 months each year before they disappear. The average last date to find deteriorated medusae in the plankton is 29 June. The small annual variation in the occurrence of the different medusa stages is paralleled by the nearly con- stant population size of Cyanea. The comparison of their peak annual abundance (Fig. 2) shows that the maxi- mum abundance of medusae (always occurring between late April and mid-May) alternates between relatively large populations in even years (1982, 1984. 1986) and relatively low populations in the odd years (1981, 1983, 1985). However, the largest population (recorded in 1986) was only times that of the smallest (1985). The content of their gastrovascular cavity (Fig. 3) is as predictable as is the temporal occurrence of their g 3 £ 2 .O E. 72 n 64 I I 56 - «f Q. 40 S » 32| 3 24 jj, D 16 .963 1985 1987 Figure 2. The relative number (this study) and volume (NUSCo, 1988) of Cyanea medusae in the Niantic River estuary, 1981-1987. (See Discussion for NUSCo data.) different stages and the range in their population size. From March through the first half of May, an average of at least 65% of medusae have copepods in their gastro- vascular cavity, during the first half of this period many also contain Palaernonetes and Mysis, replaced by am- phipods (mostly gammarids, but a few caprellids) during the second portion of this period. In the latter half of May, when many medusae also contain Nereis
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
