Cyprichromis spawning

[AlexJordan]

I came across this article today, thought it might be of interest to some:

Lunar cyclic spawning of a mouthbrooding cichlid, Cyprichromis leptosoma, in Lake Tanganyika

Abstract: Lunar reproductive cycles have rarely been documented in freshwater fishes (Schwanck, 1987; Nakai et al., 1990), although common among marine reef fishes (Robertson et al., 1990). Several hypotheses for lunar synchronous spawning have been proposed, based on the effects of the tidal regime on planktonic egg dispersal or hatching from adult habitats (Robertson et al., 1990). However, these hypotheses cannot be applied to fishes inhabiting freshwater bodies, where the lunar cycle never causes tidal fluctuations. However, some authors have proposed several explanations for the adaptive significance of lunar cyclic reproductive activity in freshwater fishes, based on the effects of moonlight. (1) Moonlight provides a cue for pairs to spawn at the same time (Schwanck, 1987). (2) Spawning prior to a full moon enhances the effectiveness of nocturnal parental care of the brood (Schwanck, 1987; Nakai et al., 1990; Rossiter, 1991). (3) Dispersal of young during the fourth quarter of the lunar cycle and the new moon improves the survival of young dispersing under the cover of darkness (Nakai et al., 1990).

Cichlid fishes that dominate the coastal fish communities in Lake Tanganyika have two well-developed patterns of parental care, substrate brooding and mouthbrooding (Coulter, 1991; Keenleyside, 1991). In this lake, about one third of the cichlid species are substrate brooders and the remainder mouthbrooders (Poll, 1986). Lunar cyclic spawning has been reported in some substrate brooders, but never in mouthbrooders. However, the spawning activity of a mouthbrooding cichlid, Cyprichromis leptosoma, in fact follows the lunar cycle at the southern end of the lake. I examined whether or not any of the three explanations for lunar spawning synchroneity are applicable to this species, and herein propose an alternative explanation that considers interspecific relationships between juvenile C. leptosoma and substrate brooding species cohabiting the area.

Search for the title at scholar.google.com if you want the full article - I'd post it up but I'm not sure if copyright allows that (although google seem immune to such concerns!)

Alex

[CThompson]

Does Lake Tanganyika gets tides? It gets surf, its huge, one would assume that it gets tides as well, there be it smaller than ones in the ocean.

[AzFish]

I think in the doco Jewel of the rift they say that Lake Tanganyika is tidal .

EDIT:

Just did a google search:

http://www.gemistar.com/tanganyika.htm

Its not tidal but 20ft waves??

[Storm Boy]

That is very interesting. Thanks for putting it up.

[CThompson]

I think in the doco Jewel of the rift they say that Lake Tanganyika is tidal .

EDIT:

Just did a google search:

http://www.gemistar.com/tanganyika.htm

Its not tidal but 20ft waves??

The Jewel of the Rift didn’t mention tides that I recall, but I was aware that it got surf (where the gobies live), but not as big as 20 foot waves.

Often have I wondered if it got tides as well, being such a large body of water, but I guess it is still small compared to the ocean.

Still I wonder if the moon doesn’t have some pull.

Thanks Aaron

Craig