Assessing the environmental and ecological drives of interannual variability in the life histories and population dynamics of icefishes (Family Channi

次南极岛屿南乔治亚岛是南大洋区域海洋生物多样性的热点，支持高度特有和山脉边缘的动物。它也是南大洋变暖最快的地区之一。这意味着许多物种可能会发现很难容忍和适应更高的温度。此外，它还是南大洋的重要捕鱼区。渔业管理由南乔治亚州和南桑威奇群岛政府在南极海生委主持下进行。这意味着GSGSSI正在管理渔业，同时缓解气候的长期变化。南乔治亚州周围鱼类动物群的一个关键组成部分是Channichhyidae科，也被称为冰鱼。冰鱼在脊椎动物中是独一无二的，因为它缺乏血液色素血红蛋白，这种适应能力可能使它们特别容易受到未来变暖的影响。冰鱼也表现出不同寻常的繁殖行为，一些物种已知表现出筑巢行为。在南乔治亚州和沙格岩的大陆架上，有三种关系密切的银鱼--短吻银鱼、尖吻银鱼和金枪鱼，它们构成了鱼类生物量的相当大比例，并为成功共存而经历了生态位分化。古纳里香头鱼是商业渔业的目标，而对其他两个物种已经采取了管理措施。然而，我们对关键的生活史过程，特别是与繁殖周期和行为有关的知识，以及这些物种内生物量和生活史阶段的时空变异性的生态和环境驱动，仍然存在重要的空白。该项目的主要目标是量化南乔治亚州大陆架和沙格岩大陆架上的冰鱼C.gennari、C.aceratus和P.georgianus的关键生活史过程、人口特性和资源分配。鉴于这些物种在生态位上的差异，预计它们对不断变化的环境条件的反应将有所不同。目前，已经制定了管理措施，限制商业渔业中作为目标或副渔获物捕捞的总生物量，但需要在区域范围内提供更多信息，以帮助向空间管理部门提供信息，并维持可存活的种群，以帮助减缓未来的变暖。需要解决的关键问题包括：1)确定潜在的产卵地点、时间和育苗场，并评估这些是否与环境或水深特征有关；2)评估幼体在招募、孵化时间和生长速度方面年际变化的环境驱动因素；3)评估岛屿周围生活史阶段的分布，以及它们在年间和年内的变化；4)量化不同物种生活史阶段之间的资源分配。

The sub-Antarctic island of South Georgia is a hotspot of regional marine biodiversity in the Southern Ocean and supports high levels of endemic and range-edge fauna. It is also one of the fastest warming areas in the Southern Ocean. This means that many species may find toleration and adaptation to higher temperatures difficult. In addition, it is an important fishing region in the Southern Ocean. The management of the fisheries is conducted by the Government of South Georgia and the South Sandwich Islands (GSGSSI) under the auspices of CCAMLR. This means GSGSSI are managing fisheries whilst mitigating against longer-term changes in climate. A key component of the fish fauna around South Georgia are the family Channichthyidae, also known as icefishes. Icefish are unique amongst vertebrates, in lacking the blood pigment haemoglobin, an adaption that may make them particularly susceptible to future warming. Icefish also exhibit unusual reproductive behaviours with some species known to show nesting behaviours. There are three species of closely related icefish Champsocephalus gunnari (mackeral icefish), Chaenocephalus aceratus and Pseudochaenichthys georgianus, which make up a substantial proportion of the fish biomass on the continental shelves of South Georgia and Shag Rocks and have undergone niche differentiation for successful coexistence. Champsocephalus gunnari is a commercial fisheries target while management measures are in place for the other two species. However, there are still important gaps in our knowledge of key life history processes, especially related to reproductive cycles and behaviour, and ecological and environmental drives of spatio-temporal variability in biomass and life history stages within these species.The main objectives of this project are to quantify key life history processes, demographic properties and resource partitioning in the icefishes C. gunnari, C. aceratus and P. georgianus on the South Georgia and Shag Rocks continental shelves. Given the differences in ecological niches for these species, it is expected that they will respond differently to fluctuating environmental conditions. At present, there are management measures in place which limit the total biomass caught as target or by-catch in the commercial fisheries, but further information is required at the regional scale to help inform the spatial management and maintain viable populations to help mitigate against future warming. Key questions which need to be addressed include:1) identify potential spawning locations, timings and nursery grounds and assess whether these are linked to environmental or bathymetric features;2) assess the environmental drivers of interannual variability in recruitment, hatching times and growth rates of larvae;3) assess the distribution of life history stages around the island and how they vary between and within years;4) quantify resource partitioning among life history stages of the different species.