The following has been taken from an article placed in the Seafood New Zealand Dec 1995 magazine, it also appears in the book Nets, Lines and Pots – A history of New Zealand fishing vessels both written by Emmanuel Makarios.
As time went by, Charles Daniel developed a keen interest in marine biology. He bought a microscope and started taking samples from a variety of fish. In 1927 work had begun on a study of snapper feeding habits. This was done as part of investigations into the impact of Danish seining on snapper. In 1928 Charles Daniel continued this research by examining the stomachs of snapper caught by commercial fishing boats. During the period July 1928 and March 1929 he examined 1,940 snapper stomachs. It was found that the diet of snapper varied at different times of the year. Charles also observed a great abundance of snapper spawn in the Hauraki Gulf during the summer schooling season. He obtained samples of eggs by towing a small net or by using a bucket to scoop up eggs from near the surface. Placing some of the eggs in jars of sea water he was able to hatch larval fish.
This interest in the reproduction of snapper, dabs and flounders, and the recording of his observations was invaluable to Marine Department scientists. One scientist he worked with closely was Mr M W Young, one of the pioneer researchers in experimental oyster culture and observation of the oyster in its environment. Some of the observations and experiments conducted by Charles Daniel in this field were of significant assistance to Mr Young, including one experiment which found that a water temperature of 19.8 Celsius was the best for the artificial impregnation of the ova of rock-oysters.
The development of oyster farms in the Auckland area was a major priority for the Fisheries section of the Marine Department. Experiments with different types of oysters had taken place with both success and failures. As a part of the effort to identify the best areas in which to set up an oyster farm, in order to get a higher yield, fisheries inspectors in charge of launches were required to keep a daily log of water temperatures and meteorological conditions. This information was used to ascertain when the water temperature was appropriate for the spawning of oysters.
When not involved with his experiments, Charles was observing fishing vessels operating out of Auckland and inspecting fish markets. Eventually he became head of the fisheries branch of the Marine Department in Auckland.
While not a trained marine biologist, his enthusiasm, commitment and inquisitiveness made up for lack of formal training. His pioneering observations regarding snapper and oysters may seem minor to today’s scientific standards but, in those early years of fisheries research, the information he gathered helped to develop fisheries we now take for granted.