Commercial Shark Fishing in the Caribbean Area 35 



can only be made in laboratories which are equipped to 

 make such analyses. The tests which you yourself make 

 can not be accurate, but even these rough analyses may 

 serve as a guide to the quality and value of your product. 

 It is not necessary for you to make tests yourself unless 

 you wish to. 



A good field testing kit is the La Motte Apparatus for 

 Measuring Vitamin A, which is manufactured by the La 

 Motte Chemical Products Company, Towson 4, Balti- 

 more, Maryland, U.S.A. This kit contains six tubes of 

 ammonia-copper sulfate solution which represent, by 

 different shades of blue, specific Vitamin A values rang- 

 ing from 5,000 to 100,000 units of Vitamin A per gram 

 of oil. The kit also contains ampules of antimony 

 trichloride reagent (25 % solution in chloroform) to 

 which you may add a drop of the oil you wish to test. A 

 blue color will result which can be compared to the col- 

 ors in the six tubes just mentioned. In this way you 

 can estimate the approximate Vitamin A content of 

 your liver oil. Full directions come with each kit, the 

 cost of which is approximately $35.00 (U.S.) f.o.b., Bal- 

 timore, Maryland. The Lovibond Tintometer is a simi- 

 lar kit, manufactured by the Lovibond Tintometer 

 British Drug House, Ltd.. Graham Street, N.I., England. 

 The approximate cost of this kit is £15. If these cost 

 too much to purchase for individual use, it might be a 

 good plan to have one available at your chief market for 

 the use of all who are bringing their catch to that point. 



Marketing Shark Livers and Oil 



The United States is a ready market for Vitamin shark 

 liver oil with its Vitamin A content. When you are 

 ready to sell your product, send a quart sample of your 

 total shipment (3 pounds if livers only) to be analyzed 

 for Vitamin A content to the prospective purchaser in 

 the United States. If the result of the analysis is satis- 

 factory, the purchaser will arrange for a letter of credit 

 to 1)0 opened for you at a local bank. This letter of 

 credit will cover only a part of the total value of the 

 shipment. You may collect this letter of credit by pre- 

 senting the shipping documents to the bank as proof that 



