Population structuring of Cod around the UK; scale, mechanism and dynamics

许多全球海洋渔业已经崩溃，或处于创纪录的低丰度水平。持续的捕捞和气候变化的不确定影响进一步增加了对鱼类资源的压力。因此，我们需要新的战略来协助我们的管理和养护工作。其中一项发展是将鱼类种群之间存在的与空间有关的生物差异的程度和动态纳入种群评估。这种资料很重要，因为大多数被开发的鱼种是由个体组合而成，个体的生长、繁殖、洄游趋势和死亡率各不相同。因此，例如，有必要使捕捞强度与捕捞后的预计补充率相匹配，从而减少个别种群灭绝的可能性。保护种群之间的这种生物差异对于维持野生鱼类种群的遗传多样性也很重要，从而赋予它们更大的进化潜力，以适应环境的变化。这项工作的一个关键组成部分是检验关于卵和幼虫的散布以及青少年和成年人的行为等因素在维持这种生物差异方面的相对作用的假设。通过整合英国三大渔业机构（FRS，CEFAS，AFBI）与英国大学，NERC研究所和来自丹麦的国际鳕鱼专家的合作伙伴的研究工作，我们将首次研究整个英国沃茨鳕鱼（Gadus morhua）种群结构的程度，模式和稳定性。我们将采用现有的（微卫星）和新的（单核苷酸多态性）遗传标记，以评估在何种程度上从不同的产卵群体的个人杂交，并将这些间接的方法进行比较，从化学分析的耳骨（“耳石”）和个人，已被电子“标记”的鱼类运动的直接测量扩散。然后，我们将输入这些数据量身定制的鳕鱼种群模型，将测试可能的影响，观察到的股票分离的模式，以及模拟的可能后果，基于空间的差异，在股票上的捕捞努力，股票恢复和海洋保护区的设计。该提案将代表英国大学和所有三个英国渔业机构首次有机会共同解决一个问题，该问题必须考虑到英国大片地区和邻近沃茨鱼类种群的相互依赖性。该提案将产生种群分离的新的遗传估计，特别是在不确定的地区，如凯尔特海和爱尔兰海以及北海南部和英吉利海峡，以及提供新的理论工具（种群模型），可用于预测持续捕捞压力和环境变化对鳕鱼种群的影响。此外，这些工具将提供关于海洋保护区的适当空间规模和分布以及现已正式濒危并列入自然保护联盟红色名录（http：//www.iucnredlist.org/）的物种种群恢复的可能速度的信息。

Many global marine fisheries have collapsed, or are at record low levels of abundance. Continuing exploitation and the uncertain impacts of climate change are adding further pressures on fish resources. New strategies are therefore required to assist in our management and conservation efforts. One such development will be to incorporate the extent and dynamics of spatially-associated biological differences that exist among fish stocks into stock assessment. Such information is important since most exploited fish species comprise assemblages of individuals that differ in their vital rates of growth, reproduction, migratory tendency and mortality. It therefore becomes desirable, for example, to match the level of fishing intensity to the projected rate of replenishment following harvesting, thereby reducing the probability that individual stocks will become extinct. Conserving such biological differences among stocks is also important in the maintenance of genetic diversity in wild fish populations, so endowing them with greater evolutionary potential for adapting to changes in the environment. A critical component of such work involves the testing of hypotheses relating to the relative contributions of such factors as dispersal of eggs and larvae, and behaviour of juveniles and adults in maintaining such biological differences. By integrating research efforts across each of the three major UK fisheries agencies (FRS, CEFAS, AFBI) with partners in UK Universities, a NERC Institute and an international cod expert from Denmark, we will for the first time examine the extent, patterns and stability of cod (Gadus morhua) population structuring throughout UK waters. We will employ existing (microsatellites) and new (single nucleotide polymorphisms) genetic markers to assess the extent to which individuals from different spawning groups interbreed, and will compare these indirect methods of dispersal with direct measure of fish movement taken from chemical analysis of ear-bones ('otoliths') and individuals that have been electronically 'tagged'. We will then input these data to tailored cod population models that will test the likely effects of young-stage and adult dispersal on observed patterns of stock separation, as well as simulating the likely consequences of spatially-based differences in stocks on such things as fishing effort, stock recovery and the design of marine protected areas. The proposal will represent the first opportunity for UK Universities and all three UK Fisheries agencies to work together on a problem that has to take account of the interdependence of fish stocks across large regions of UK and adjoining waters. The proposal will generate new genetic estimates of stock separation, especially in areas of uncertainty such as the Celtic and Irish Seas and the Southern North Sea and English Channel, as well as the provision of new theoretical tools (population models) than can be used to forecast the impact of continued fishing pressure and environmental change on cod populations. Moreover, the tools will provide information on the appropriate spatial scale and distribution of marine protected areas and the probable rates of stock recovery in a species that is now formally endangered and listed in the IUCN Red List (http://www.iucnredlist.org/).