The reproductive biology of an open-water spawning Lake Malawi cichlid, Copadichromis chrysonotus
The reproductive biology of an open-water spawning Lake Malawi cichlid, Copadichromis chrysonotus
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开放水域产卵的马拉维湖丽鱼科鱼 Copadichromis chrysonotus 的生殖生物学
DOI：
10.1080/15627020.2000.11657086
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
Lance W. Smith
中科院分区：
文献类型：
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作者：
Lance W. Smith
Copadichromis chrysonotus是一种食动物的慈鲷科鱼类，栖息在马拉维湖的岩石，沿岸的栖息地。像大多数马拉维湖慈鲷一样，这个物种的繁殖策略是基于母体的口孵，但它是已知的唯一在开放水域产卵而没有基质领土的沿岸的物种。本研究调查了中华绒螯蟹的成熟体长、性二型、产卵行为、繁殖季节性、产卵量、育性、卵大小和育雏习性。产于马拉维湖南部。繁殖色的雄性聚集在至少几米深的遮蔽区域，每只雄性在试图吸引雌性的同时，保卫着靠近水面的移动的繁殖领地。繁殖主要是从8月到5月连续进行，8月至9月和1月至3月是高峰期。5月和6月是繁殖活动的主要间歇期。平均产卵量和受精率随体长的增加而显著增加，而平均卵长、平均卵质量和性腺指数随体长的增加而不显著增加。雌性在抛弃幼仔之前，将幼仔孵化至全长15-16毫米。开放水域产卵C. chrysonotus可能是一种适应，以减少产卵期间的卵捕食和对基于基质的繁殖区的竞争。
Copadichromis chrysonotus is a zooplanktivorous cichlid member of the diverse fish community inhabiting Lake Malawi’s rocky, littoral habitat. Like most Lake Malawi cichlids, this species’ reproductive strategy is based on maternal mouthbrooding, but it is the only littoral species known to spawn in the open water without a substrate-based territory. This studyinvestigated length at maturity, sexual dimorphism, spawning behaviour, breeding seasonality, fecundity, fertility, egg size, and brooding habits of C. chrysonotus in southern Lake Malawi. Males in breeding colouration aggregated in sheltered areas at least several metres deep, and each male defended a mobile breeding territory near the surface while attempting toattract females. Breeding was mostly continuous from August to May, with peaks in August–September and January–March. A major lull in breeding activity occurred in May and June. Mean fecundity and fertility increased significantly with female total length, while mean egg length, mean egg mass and gonadosomatic index did not increase significantly with female totallength. Females brooded their young up to 15–16 mm total length before abandoning them. Open-water spawning by C. chrysonotus may be an adaptation to reduce both egg predation during spawning and competition for substrate-based breeding territories.