35 



PART V- STARFISH AS FERTIUZER 

 By Charles F. Lee* 



INTRODUCTION 



The four previous papers of this series of technological studies of the star- 

 fish ( Asterias forbesi) have reported data in the literature, as well as those 

 obtained in these investigations on the chemical composition of starfish, use of 

 starfish meal as a protein feedstuff, and on the presence of thiaminase in raw 

 starfish and starfish meal. The present paper gives the results of an investigation 

 on a small local scale directed towards the better utilization of starfish as fer- 

 tilizer. 



Most of the reports on the utilization of starfish prior to 1942 have been 

 concerned with its value as fertilizer (Kole, 1919 and Vachon, 1920). Since 1942, 

 the dried starfish meal has been found to have sufficient value as a protein sup- 

 plement for poultry feeds so that any meal which could be produced could be used 

 for this purpose. The only recent reports of its use as fertilizer have been limited 

 to the use of whole raw starfish. The starfish landed at Providence during the 

 period when the State of Rhode Island was paying bounty on the pests were disposed 

 of in this way (Gibbs, 1941 and 1946). There have been other unpublished reports 

 of similar use of small quantities on private gardens and small farms . 



In general, reports of the use of starfish for fertilizer have been quite 

 favorable. So far as is known, however, none of the trials have been adequately 

 planned, with control and competitive plots, to permit comparison of starfish with 

 balanced commercial fertilizers. 



Starfish, on the basis of chemical analysis, is a source of organically bound 

 nitrogen, containing negligible amounts of phosphorus and potassium, the latter 

 two elements being of primary importance in balanced fertilizers. The ash content, 

 largely calcium carbonate, may amount to 60 percent by weight of the meal and 

 dilutes the nitrogen to a fairly low value, less than 5 percent on a dry matter 

 basis. As a fertilizer, this calcium carbonate is a desirable addition for acid 

 or "heavy" soils. Starfish were not being used in any way and since they have 

 some fertilizer value, an investigation was made to determine a practical way to 

 use raw starfish as fertilizer. Most starfish are taken in the spring and summer, 

 and piles of raw, untreated starfish decompose rapidly at the temperatures pre- 

 vailing during these seasons . The odors thus developed would condemn handling 

 * Chemical Engineer, Fishery Technological Laboratory, Branch of Commercial Fisheries, College 



Park, Maryland. 

 NOTEi Part I of this series, "Starfish Control— Its Economic Necessity and Methods Used," 

 appeared in the January 194° issue of Commercial Fisheries Review , pp. 1-6. Also available 

 as Sep. No. 193. 



Part II, "Chemical Composition," appeared in the February 1948 issue, pp. 11-18. Also 

 available as Sep. No. 196. 



Part III, "Value of Starfish Msal — Protein Supplement for Growth of Rats and Chicks and 

 for Egg Production," appeared in the March 1948 issue, pp. 8-19. Also available as Sep. 

 No. 199. 



Part IV, "Thiaminase in Starfish," appeared in the May 1948 issue, pp. 13-19, Also 

 available a3 Sep. No. 204. 



