PREDATION MORTALITY OF BAY ANCHOVY ANCHOA-MITCHILLI EGGS AND LARVAE DUE TO SCYPHOMEDUSAE AND CTENOPHORES IN CHESAPEAKE BAY
PREDATION MORTALITY OF BAY ANCHOVY ANCHOA-MITCHILLI EGGS AND LARVAE DUE TO SCYPHOMEDUSAE AND CTENOPHORES IN CHESAPEAKE BAY
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DOI：
10.3354/meps114047
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发表时间：
1994-11-01
影响因子：
2.5
通讯作者：
GAMBLE, JC
中科院分区：
文献类型：
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作者：
PURCELL, JE;NEMAZIE, DA;GAMBLE, JC
1991年7月，在美国切萨皮克湾4个站位，测定了大量的五爪金蜥和拟栉水母对海湾小鳀卵和仔鱼的捕食率，并与同期鱼类调查中的卵和仔鱼死亡率进行了比较。水母和栉水母的每日捕食是19 +/- 13%（平均值+/- SD）的鸡蛋在20小时的阶段持续时间，水母负责26至100%的捕食。这些凝胶状捕食者占估计的每日卵期死亡率的21 +/- 17%。平均而言，水母消耗29 +/- 14% d（-1）的幼虫干草饲料，这是41 +/- 35%的总估计幼虫死亡率。没有发现栉水母对幼虫的捕食作用。将这些捕食效应与在自由漂移的3.2 m（3）围隔生态系统中同时测量的效应进行比较。我们的结论是，水母，这有高的摄食率，但低丰度，和栉水母，这有低的摄食率，但高丰度，是重要的捕食者的海湾卵和幼虫的中盐区的切萨皮克湾。
We measured predation on bay anchovy Anchoa mitchilli eggs and larvae by abundant scyphomedusae Chrysaora quinquecirrha and ctenophores Mnemiopsis leidyi from gut contents, digestion rates, and densities of predators and prey during 9 d in July 1991 at 4 stations in Chesapeake Bay, USA, These predation rates were compared to egg and larval mortality rates measured concurrently in ichthyoplankton surveys. Daily predation by medusae and ctenophores was 19 +/- 13% (mean +/- SD) of the eggs over the 20 h stage duration, with medusae responsible for 26 to 100% of the predation. These gelatinous predators accounted for 21 +/- 17% of the total estimated daily egg-stage mortality. On average, medusae consumed 29 +/- 14% d(-1) of the larval hay anchovy, which was 41 +/- 35% of total estimated larval mortality. Predation on larvae by ctenophores was not detected. These predation effects are compared with those measured concurrently in free-drifting 3.2 m(3) mesocosms. We conclude that medusae, which had high feeding rates but low abundances, and ctenophores, which had low feeding rates but high abundances, were important predators of bay anchovy eggs and larvae in the mesohaline region of Chesapeake Bay.