Collaborative Research: Connectivity of Reef Fish Populations: Mechanisms and Consequences

大多数珊瑚鱼的幼体在孵化后不久就会离开出生的珊瑚礁，经过几天到几周的中上层阶段后返回珊瑚礁环境。洋流被认为会使幼虫广泛分散，从而导致珊瑚礁种群之间广泛的遗传联系。在最近研究的一些案例中，连通性似乎比先前假设的更有限，自我招募(在出生的珊瑚礁上定居)更常见。这可能是有利的水文条件的结果，可能是由于幼虫的行为成分利用游泳和感官能力，通过利用适当的水流保持在珊瑚礁附近。关于大鱼Apogon doederleini遗传结构的初步数据表明，在7至18公里的地理范围内，珊瑚礁种群之间存在显著差异。使用水文模型可以预测珊瑚礁之间的遗传差异。这表明幼虫的行为在保留和自我招募中起着积极的作用。该项目将确定具有不同幼体生物学的三种珊瑚鱼的遗传种群结构，并研究扩散和补充行为的机制。目标是：(1)连续两年确定鱼群内和礁群之间鱼类的遗传亚结构程度及其时间稳定性，空间尺度约为。10至20千米，以三种不同扩散生物学的物种为基础。(2a)确定这三个物种的定居前幼鱼是否区分水文上或多或少相连的珊瑚礁的气味，以及(B)确定它们对珊瑚礁气味偏好的时间稳定性。(3)扩展不同来源种群在所建议的礁群中的水文扩散模型，并将结果与遗传分析和气味偏好测试的连通性结果进行比较。为了进行遗传分析，将使用DNA微卫星标记研究地理距离以及扩散联系和障碍，该标记以澳大利亚大堡礁摩羯座/堡垒群中的一个树岛为中心。OTI地区的水文模型将被用来预测平流扩散。将比较三个物种在安置仔鱼/幼鱼时的遗传亚结构和珊瑚礁气味偏好：(B)多刺五加(无浮游阶段)，(B)Apogon doederleini(浮游，弱游泳者)和(C)Pomacenter us Coelstis(浮游，强游者)。用于气味选择测试的迷你水槽将在船上使用，在这些船只上，单一定居阶段的鱼类对特定珊瑚礁表现出显著的气味偏好。智力上的优点是1)珊瑚礁鱼类遗传亚结构的规模影响有关珊瑚礁连通性的概念，2)水文分布预测与遗传种群结构之间的差异，3)珊瑚礁鱼类幼虫辨别紧密相连珊瑚礁气味的嗅觉能力，4)气味偏好与遗传种群结构之间的可能联系，暗示早期印记和保留在出生珊瑚礁附近。更广泛的影响在于1)珊瑚礁养护和管理(连通性、水质)，2)培训下一代科学家，研究生物海洋学、行为生态学、进化和(海洋)养护，3)国际合作。

The larvae of most reef fishes disperse from the natal reef soon after hatching and return to the reef environment after a pelagic stage of several days to weeks. Ocean currents were assumed to disperse larvae widely, resulting in broad genetic connectivity between reef populations. In some recently studied cases, connectivity appears to be more limited and self-recruitment (settlement on natal reefs) more common than previously assumed. This may be the result of favorable hydrographic conditions, perhaps aided by a behavioral component of larvae using swimming and sensory capabilities to stay in proximity to a reef by using appropriate currents. Preliminary data on the genetic structure of the cardinalfish Apogon doederleini show significant differences between reef populations at the geographical scale of 7 to 18 km. Genetic differences between reefs using a hydrographic model would have predicted panmixis. This suggests that larval behavior plays an active role in retention and self-recruitment. This project will determine the genetic population structure of three reef fish species with different larval biology and study mechanisms of dispersal and recruitment behavior. The objectives are: (1) Determine in two consecutive years the degree of genetic substructure and its temporal stability of fish within and among reef clusters at spatial scales of approx. 10 to 20 km based on three species with different dispersal biology. (2a) Determine whether pre-settlement juveniles of the three species differentiate between odors of hydrographically more or less connected reefs and (b) Determine the temporal stability of their reef odor preference. (3) Extend the hydrographic dispersal model for different source populations among the proposed reef clusters and compare the results with connectivity results from genetic analysis and odor preference tests. For genetic analysis, geographic distances and dispersal links and barriers will be studied using DNA microsatellite markers, centered around One Tree Island in the Capricorn/Bunker group of reefs in the Great Barrier Reef, Australia. The hydrographic model of the OTI region will be employed to predict dispersal by advection. Genetic substructure and reef odor preference in settling larvae/juveniles of three species will be compared: Acanthochromis polyacanthus (no pelagic stage), (b) Apogon doederleini (pelagic, weak swimmers) and (c) Pomacentrus coelestis (pelagic, strong swimmers). A mini-flume for odor choice tests will be used on-board ships in which single settlement stage fish have shown significant odor preference for specific reefs.Intellectual merits are demonstrations of 1) the scale of genetic substructure in coral reef fishes impacting concepts about the scale of reef connectivity, 2) differences between hydrographic dispersal predictions and genetic population structure, 3) olfactory capabilities of reef fish larvae to discriminate between odors of closely linked reefs, 4) possible connections between odor preference and genetic population structure suggestive of early imprinting and retention near natal reefs. Broader impacts are in 1) coral reef conservation and management (connectivity, water quality), 2) training of the next generation of scientists in biological oceanography, behavioral ecology, evolution and (marine) conservation, 3) international collaboration.