The Sargassum and the Flying Fish!

 

Quite frequently, in high summer, one can spot certain clumps of Gulf Weed that seem much more solidly packed than the usual loose-bait bundles. Some are so solid as to appear impenetrable. Each is usually about the size of a football. Upon close inspection the immediate impression is of something not very nice! The ball appears to be riddled with fungus and possibly something that has died and is beginning to decompose. In fact it is the exact opposite. This apparently moribund ball is positively throbbing with life - new life!

 

The object in question is a nest and appropriately its designer and builder flies……..but it's a fish! These balls are flying fish nests and they are full of developing eggs - each with perfect pepper and salt coloured fish embryo within, complete with heart, eyes, ears (otoliths) and segmented body and tail. Beneath the chin and wide mouth of each embryo beats a big heart, which by week two is pumping bright red blood throughout the embryo. Periodically the embryos wriggle violently and shift position. In late development they are so beautiful and their well developed pigment cells in brown, black, yellow and orange hint at the colour the emerging larval flying fish will acquire for the first few months of its life.

William Beebe (the same of Deep Sea fame) studied these larvae thoroughly and he concluded that this was a species not before described and therefore named by him the "Sargassum flying fish". The adult which he noted was like a delicate moth, flitting in and out of Sargassum clumps he refered to as the "Many-coloured butterflying fish".

It took about forty or fifty years for Günther to point out the error of Beebe's ways. He showed that indeed this was the juvenile stage and early life stages of the 'Blue and Silver Atlantic Flying Fish' - sometimes called the 'Four-wing Flying Fish' - the one we see glide for up to four or five hundred metres at a time when disturbed at the surface. These adults pair close by Sargassum and while the female lays eggs and secretes silken threads to enmesh both weed and eggs, the male, we suspect synchronously, fertilises the brood by following the female in, through and around the ever enlarging nest - a little reminiscent of the classic Three-spined-stickleback process of courtship and fertilisation. I don't believe there is any indication of internal fertilisation in this species and the above process, though speculative, would appear to be one of the few possible options. We would love to receive feedback on this point if any readers have witnessed part, or all, of the process.

© 2000 by Image Quest 3-D
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