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从纳塔尔的珊瑚礁中扩散，并在几天至几周的浮游阶段后返回珊瑚礁环境。 洋流被假定为广泛传播幼虫，导致珊瑚礁种群之间存在广泛的遗传联系。 在最近研究的一些案例中，连通性似乎更有限，自我补充（在纳塔尔珊瑚礁上定居）比以前假设的更常见。 这可能是有利的水文条件的结果，也许是由幼虫的行为组成部分使用游泳和感官能力，通过使用适当的电流留在附近的珊瑚礁。 对红雀Apogon doederleini的遗传结构的初步数据显示，在7至18公里的地理尺度的珊瑚礁种群之间的显着差异。 使用水文模型的珊瑚礁之间的遗传差异将预测panmixis。这表明，幼虫的行为起着积极的作用，在保留和自我招聘。 本计画将探讨三种不同幼体生物学的礁鱼的遗传族群结构，并研究扩散与补充行为的机制。 目标是：（1）连续两年确定珊瑚礁群内和珊瑚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公里，根据三种不同的扩散生物学。(2a)确定是否定居前的少年的三个物种区分水文或多或少连接的珊瑚礁的气味和（B）确定他们的珊瑚礁气味偏好的时间稳定性。 (3)扩展水文扩散模型，为不同的源种群之间的建议的珊瑚礁集群，并比较结果与遗传分析和气味偏好测试的连接结果。 对于遗传分析，将使用DNA微卫星标记研究地理距离和扩散联系和障碍，以澳大利亚大堡礁摩羯座/掩体群珊瑚礁中的一棵树岛为中心。 OTI地区的水文模型将用于预测平流扩散。 遗传结构和珊瑚礁气味偏好在解决幼虫/三个物种的少年：Acanthochromis polyacanthus（无远洋阶段），（B）Apogon doederleini（远洋，弱游泳者）和（c）Pomacentrus coelestis（远洋，强游泳者）。 一个小型水槽的气味选择测试将被用于船上，其中单一定居阶段的鱼类已显示出显着的气味偏好特定的reefs.Intellectual优点是1）珊瑚礁鱼类的遗传结构的规模影响有关的珊瑚礁连接的规模的概念，2）水文扩散预测和遗传种群结构之间的差异，3）珊瑚鱼幼体的嗅觉能力，以区分气味的密切联系的珊瑚礁，4）气味偏好和遗传种群结构之间的可能联系，暗示早期印记和保留纳塔尔礁附近。 更广泛的影响是：1）珊瑚礁的保护和管理（连通性，水质），2）在生物海洋学，行为生态学，进化和（海洋）保护方面培训下一代科学家，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.