Recently, there was an article aired in the media concerning the utilization of fish by ensilaging techniques. According to Minister of Maritime Affairs and the Blue Economy, Kirk Humphrey, “between 30 and 70 per cent of fish caught by local fishermen is currently being wasted”. The project, entitled the “Fish Waste Silage” project is aimed “at transforming parts of the fish which currently go to waste into perfectly safe, nutritious products for human and livestock consumption”. “We are not catching enough fish. And even though we are not catching enough fish, a lot of what we do catch is wasted . . . they say up to 30 to 70 per cent of every fish is wasted in Barbados and that is” ….. said Humphrey, who added “that a large percentage of the fish caught was thrown back into the nearshore, polluting the waters around the island and creating an environmental hazard”. Minister of Agriculture and Food Security, Indar Weir added that the production of feed from fish could yield tremendous benefits for farmers struggling to make ends meet, given the high cost of imported feed for their livestock (New use for discarded fish .Barbados Today, February 1, 2019).
All I could do was laugh, as judging by the muddled statements above, one is left unsure of what exactly the minister wants to convey to the public. Is he saying that the dressing out percentage (DOP) of fish which have been gutted, skinned and so on, is between 30-70 percent of the original weight of the undressed fish? Or is he saying that between 30-70 percent of the catch is so-called trash fish? It is instructive to note that the actual tonnage of fish caught is not given. Is he talking about 30-70 percent of 100,000 tons or is the figure 5,000 tons? In any event, according (Barlow, S.M. Fish meal manufacture in the tropics: Proceedings of the Conference on the Handling,Processing and Marketing of Tropical Fish, Tropical Product Institute, London, 5th.-9th. June 1976, p223-237):“ it is necessary to have a realistic estimate of the raw material which will be available to the factory and its seasonality. This will have an important effect on the economics of a fish meal operation and the type and capacity of the plant required.” These were profound words then and now. I am not sure about the throwing back into sea of fish; is he referring to the local fishermen whose boats are not that big anyhow or to the Japanese and Chinese factory ships?
Let me start by saying that my doctoral thesis was in the field of fermented sausages. (Department of Chemical Engineering, St. Augustine, UWI. Trinidad,1980). Ensilaging of fish waste is a fermented procedure. In either instance,fermentation can be effected by the addition of organic acid or by the the use of lactic-acid bacteria. In the latter case, a pure culture of the desired strain of lactic-acid bacteria(L. plantarum) is used. A homo-fermentative strain is required ( that is a strain which produces lactic acid as apart from a hetero-fermentative which produces lactic acid and carbon dioxide for obvious reasons).In both instances, there is a need to effect a rapid decrease in the pH of the sausage dough or the fish waste. A pH value of 4.3 is normally adequate enough to preclude the growth and elaboration of toxins by pathogens. The process depends basically on the lactic acid or added organic acid creating conditions hostile to the growth of micro-organisms. What the minister is talking about is nothing new. I have written numerous letters to press about using fermentation techniques to obtain animal rations. On the 10th.August 1994, in a letter to the Advocate entitled : “True sustainability”, I outlined ways of converting so-called trash fish into surimi (a fish product that is bland and can be kept frozen for a long time without becoming rancid,that is used in imitation crab and so on). I also outlined the process in a paper (Lucas, R. D. 2005. “A Preliminary Sensory Evaluation Of Fish Burgers And Breakfast Sausages Made From king Fish(Scomberomorns cavalla)Surimi In Grenada, West Indies.” Proceedings of The First Biennial Science and Technology Symposium, Barbados National Council For Science And Technology,March 8-9th. Pp 38-40).
Robert D. Lucas, PH.D.,CFS
Certified Food Scientist.