Abstract:
Heavy metals pollution causes a threat to the aquatic environment and to its inhabitants when their concentrations exceed safe limits. Heavy metals cause toxicity in fish due to their non-biodegradable properties and their long persistence in the environment. This review investigated the effects of heavy metals on early development, growth and reproduction of fish. Fish embryos/larvae and each developmental stage of embryo respond differently to the intoxication and vary from species to species, types of metals and their mode of actions, concentration of heavy metals and their exposure time. Many of the heavy metals are considered as essential nutrient elements that positively improve the growth and feed utilization of fishes but upon crossing the maximum tolerable limit these metals cause not only a hazard to fish health but also to human consumers and the disruption of ecological systems. Reduced gonadosomatic index (GSI), fecundity, hatching rate, fertilization success, abnormal shape of reproductive organs, and finally failure of reproduction in fish have been attributed to heavy metal toxicity. In summary, this review sheds light on the manipulation of fish physiology by heavy metals and seeks to raise sensitivity to the prevention and control of aquatic environmental contamination, particularly from heavy metals.
摘要:
当重金属的浓度超过安全限值时,重金属污染会对水生环境及其居民构成威胁。重金属由于其不可生物降解的特性和在环境中的长期持久性而在鱼中引起毒性。这篇综述调查了重金属对早期发育的影响,鱼的生长和繁殖。鱼胚胎/幼虫和胚胎的每个发育阶段对中毒的反应不同,并且因物种而异,金属的类型及其作用方式,重金属的浓度及其暴露时间。许多重金属被认为是积极改善鱼类生长和饲料利用率的必需营养元素,但在跨越最大容许极限时,这些金属不仅对鱼类健康造成危害,而且对人类消费者造成危害,并破坏生态系统。降低性腺指数(GSI),繁殖力,孵化率,受精成功,生殖器官形状异常,最后,鱼类繁殖失败归因于重金属毒性。总之,这篇综述揭示了重金属对鱼类生理的操纵,并试图提高对水生环境污染的预防和控制的敏感性,特别是重金属。