. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. DENNIS M. ALLEN _ 20 O • • Station 1 o- o Station 7. JJASONDJ FMAMJJASONDJFMAMJ 1975 I 1976 I 1977 FIGURE 2. Mean monthly bottom water temperatures at UB station 1 and ocean station 7 from June 1975 to June 1977. Collections were also made on the intertidal flats of Delaware Bay at Norburys Landing, New Jersey (Fig. 1). Samples were taken with hand-held sweep nets in shallow water every 1-3 days from late March to early June 1978. Salinities varied between 18 and 27%o and temperatures from 4 to 22°C. M. borealis specimens we
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. DENNIS M. ALLEN _ 20 O • • Station 1 o- o Station 7. JJASONDJ FMAMJJASONDJFMAMJ 1975 I 1976 I 1977 FIGURE 2. Mean monthly bottom water temperatures at UB station 1 and ocean station 7 from June 1975 to June 1977. Collections were also made on the intertidal flats of Delaware Bay at Norburys Landing, New Jersey (Fig. 1). Samples were taken with hand-held sweep nets in shallow water every 1-3 days from late March to early June 1978. Salinities varied between 18 and 27%o and temperatures from 4 to 22°C. M. borealis specimens were maintained in a running sea water system from December through May each year. The swimming and attachment behavior of the leeches were observed. Small groups of leeches were isolated with mysid hosts in static aquaria at different temperatures for observations on reproduction and lon- gevity. Experiments were conducted to determine the temperature and salinity toler- ances of M. borealis. Plastic containers, each with 350 ml of water at one of five salinities (0, 10, 15, 20, and 30%o) were placed into constant temperature baths and allowed to equilibrate for at least 12h. Tests were run at six temperatures (0, 10, 15, 20, 22, and 25°C) and all temperature-salinity combinations were tested two or three times. Ten adult leeches and twelve mature N. americana were placed in each container without prior acclimation, and percentage survival was recorded each day for 10 days. RESULTS Mysidobdella borealis occurred in 120 of the 424 epibenthic sled collections made in the regular sampling program. The mysid host, Neomysis americana, was in all samples. Ratios of leeches to mysids greater than 1:100 were found in 20 of the 120 collections in which leeches occurred. The highest incidence was :100 on 21 March 1977, at station 1. The greatest number of leeches taken in a 5-min tow was 744 (with 16,648 mysids) on 26 December 1975. The mean monthly values for numbers of M. borea
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
