Abstract Mangroves and lagoons are spawning and nursery grounds of marine fish. These ecosystems are increasingly exposed to episodes of extreme temperatures from marine heatwaves (MHWs). However, it is unknown how MHW effects may interact with those of predators to affect the fitness of prey species in these ecosystems. To address the issue, we exposed the calanoid copepod Pseudodiaptomus incisus to a simulated MHW and with/without the presence of fish predator cues (FPC). The size at maturity, clutch size, hatching success, lifetime nauplii and faecal pellet production, and the adult lifespan were determined. All fitness parameters of P. incisus were lower under MHW. Remarkably, nauplii production was reduced 80%, and adult lifespan was shortened 50%, respectively. Overall, FPC increased the size at maturity and hatching at both temperatures. FPC also increased clutch size, nauplii and faecal pellet production in the control temperature, but decreased all three parameters under MHW. These results suggest that FPC may increase the vulnerability of P. incisus to MHWs by lowering reproductive success and reducing grazing rate. Our study sheds light on how interactive effects between biotic and abiotic factors may shape the vulnerability of marine copepods in mangroves and lagoons of tropical regions.

中文翻译：

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捕食者线索增加了模拟海洋热浪对热带浮游动物的负面影响

摘要 红树林和泻湖是海洋鱼类的产卵和育苗场。这些生态系统越来越多地暴露于海洋热浪 (MHW) 带来的极端温度。然而，尚不清楚 MHW 效应如何与捕食者的效应相互作用以影响这些生态系统中猎物物种的适应性。为了解决这个问题，我们将calanoid桡足类 Pseudodiaptomus incisus 暴露于模拟的 MHW 和有/没有鱼类捕食者线索 (FPC) 的存在。确定成熟时的大小、离合器大小、孵化成功率、终生无节幼体和粪便颗粒产量以及成虫寿命。P. incisus 的所有适应度参数在 MHW 下均较低。值得注意的是，无节幼体产量分别减少了 80%，成体寿命分别缩短了 50%。总体而言，FPC 在两种温度下都增加了成熟和孵化时的尺寸。FPC 在控制温度下还增加了离合器尺寸、无节幼体和粪便颗粒产量，但在 MHW 下降低了所有三个参数。这些结果表明 FPC 可能通过降低繁殖成功率和降低放牧率来增加 P. incisus 对 MHW 的脆弱性。我们的研究阐明了生物和非生物因素之间的相互作用如何影响热带地区红树林和泻湖中海洋桡足类的脆弱性。