Cottingham Alan, Huang Peisheng, Hipsey Matthew R, Hall Norman G, Ashworth Eloise, Williams Joel, Potter Ian C
Centre for Sustainable Aquatic Ecosystems Harry Butler Institute School of Veterinary and Life Sciences Murdoch University Murdoch WA Australia.
UWA School of Agriculture and Environment The University of Western Australia Crawley WA Australia.
Ecol Evol. 2018 Jun 25;8(14):7111-7130. doi: 10.1002/ece3.4236. eCollection 2018 Jul.
Understanding challenges posed by climate change to estuaries and their faunas remains a high priority for managing these systems and their communities. Freshwater discharge into a range of estuary types in south-western Australia between 1990 and 2015 is shown to be related to rainfall. This largely accounts for decreases in discharge in this microtidal region being more pronounced on the west coast than south coast, where rainfall decline was less. Results of an oxygen-balance model imply that, as demonstrated by empirical data for the Swan River Estuary, declines in discharge into a range of estuary types would be accompanied by increases in the extent of hypoxia. In 2013-15, growth and body condition of the teleost varied markedly among three permanently open, one intermittently-open, one seasonally-closed and one normally-closed estuary, with average time taken by females to reach the minimum legal length (MLL) of 250 mm ranging from 3.6 to 17.7 years. It is proposed that, in a given restricted period, these inter-estuary variations in biological characteristics are related more to differences in factors, such as food resources and density, than to temperature and salinity. The biological characteristics of in the four estuaries, for which there are historical data, changed markedly between 1993-96 and 2013-15. Growth of both sexes, and also body condition in all but the normally-closed estuary, declined, with females taking between 1.7 and 2.9 times longer to attain the MLL. Irrespective of period, body condition, and growth are positively related. Age at maturity typically increased between periods, but length at maturity declined only in the estuary in which growth was greatest. The plasticity of the biological characteristics of , allied with confinement to its natal estuary and ability to tolerate a wide range of environmental conditions, makes this sparid and comparable species excellent subjects for assessing estuarine "health."
了解气候变化对河口及其动物群构成的挑战仍然是管理这些系统及其群落的首要任务。研究表明，1990年至2015年期间，澳大利亚西南部一系列河口类型的淡水排放与降雨有关。这在很大程度上解释了该微潮区域西海岸的流量减少比南海岸更为明显，因为南海岸的降雨量下降较少。氧平衡模型的结果表明，正如天鹅河河口的经验数据所显示的那样，一系列河口类型的流量下降将伴随着缺氧范围的增加。2013 - 2015年期间，硬骨鱼的生长和身体状况在三个常年开放、一个间歇性开放、一个季节性封闭和一个常年封闭的河口之间存在显著差异，雌性达到250毫米最小合法长度（MLL）的平均时间从3.6年到17.7年不等。有人提出，在给定的受限时期内，这些河口间生物特征的差异更多地与食物资源和密度等因素的差异有关，而不是与温度和盐度有关。有历史数据的四个河口的硬骨鱼生物特征在1993 - 1996年和2013 - 2015年之间发生了显著变化。两性的生长以及除常年封闭河口外所有河口的身体状况都有所下降，雌性达到MLL的时间延长了1.7至2.9倍。无论时期如何，身体状况和生长都呈正相关。成熟期的年龄通常在不同时期有所增加，但仅在生长最快的河口，成熟时的体长有所下降。硬骨鱼生物特征的可塑性，加上其对出生地河口的限制以及对广泛环境条件的耐受性，使得这种鲷科鱼及类似物种成为评估河口“健康状况”的理想对象。
