New insight into breeding behaviour of Yellow tangs


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Scientists studying the reproduction of the Yellow tang have found that their breeding behaviour is linked to the cycle of the moon and peaks in the late spring and summer.

Experts from the University of Hawaii's Cooperative Fishery Research Unit examined the breeding behaviour of the Yellow tang, Zebrasoma flavescens, over an entire year to see how the number of eggs produced varied.

Their findings, which have just been published in the Journal of Fish Biology, reveal that reproductive effort peaked in late spring and summer with females producing large numbers of eggs and spawning for at least two consecutive days.

Depending on the time that the fish were sampled, females were carrying anywhere from 44 to 24,000 eggs. As usual with fishes, smaller specimens of 8-12cm produced limited numbers of eggs, while larger fish over 12cm produced more than 20,000 per batch.

The authors said: "This study illustrates the importance of accounting for potential variation in egg production over time, especially with respect to diel and lunar cycles, in the design of reproductive studies of multiple-spawning fishes.

"Greater insight into the environmental factors that regulate reproductive activity may be gained by determining the relative reproductive investment allocated at each spawning event.

"The ability to estimate annual fecundity for more multiple-spawning species will facilitate examination of the effects of fishing on the reproductive characteristics of these populations and permit examination of life-history evolution across a broader suite of fishes."

Yellow tangs are a popular fish with marine fishkeepers and are commercially harvested from Hawaiian waters.

For more information see the paper: Bushnell ME, Claisse JT and CW Laidley (2010) - Lunar and seasonal patterns in fecundity of an indeterminate, multiple-spawning surgeonfish, the yellow tang Zebrasoma flavescens. Journal of Fish Biology, Volume 76, Issue 6, pages 1343-1361.