Sunday, 21 February 2016

‘Lactation’ in Discus Fish: Water Life magazine follows up

In the final months before Water Life (renamed Fishkeeping and Water Life for its final year) was closed down, it followed up on its articles on breeding discus fish.

In July 1958, Professor Clifford Emmens wrote an article, Hormones and reproduction in fishes, which contained a photograph by Roy Skipper of an adult discus with young. In that article, he suggested that the production of mucus for feeding the young was most likely under the control of the pituitary hormone, prolactin, rather than the sex hormones, oestrogen and androgen. This prediction was upheld by work in Japan and Germany that was published in 1962 and 1965.


Clifford Walter Emmens (1913-99) was then Professor of Veterinary Physiology in the University of Sydney but also a well-known aquarist. A man of ‘incandescent temper’, he was well known in London because he had worked at the National Institute of Medical Research on reproductive physiology. He had a distinguished record in the Second World War, working in Zuckerman’s team that became the Bombing Survey Unit; he became an accomplished statistician, writing a book on bioassay.

In the final issue of December 1958, Roy and Gwen Skipper had another article, Breeding Pompadour fish, What the microscope reveals. This shows the sections of scales taken from parental and non-parental fish by Hildemann. I think they are the figures from Hildemann’s paper but which are missing from the rather badly scanned online version of the latter. I have scanned them from the article and arranged them so that they clearly demonstrate the thickened outer epidermis and the enlarged mucus-producing cells in those fish with young:


   
   


Photomicrographs of sections of scales taken by W.H. Hildemann from
the Skippers' non-parental and parental discus fish. Note the enlarged
mucus-producing cells and the hypertrophied epidermis

Meanwhile, in the August 1958 issue, it was reported that Roy Skipper had given up fishkeeping because of increased  business commitments and that his entire stock of fish (including breeding pairs of discus), plants, equipment, books and photographs had been advertised for sale in the previous issue (July 1958). Also shown was a photograph (reproduced) of Roy Skipper collecting daphnia from a pond. That looked like the end but the Skippers later  returned to fishkeeping with a retail shop, The House of Fishes in Hemel Hempstead, Hertfordshire.


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Emmens CW. 1958. Hormones and reproduction in fishes. Fishkeeping and Water Life 13 (9 new issue, July 1958) 441-443.

Skipper R, Skipper G. 1958 Breeding Pompadour fish. What the microscope reveals. Fishkeeping and Water Life 13 (14 new issue, December 1958) 700.