35 



The water iu the deep parts of tlie Great Belt was then completely 

 changed from tlie spring by the flowing in of new water; it had a tempera- 

 ture of c. 13", and a salinitj' of c. 28 "/oo- Iq the month of July (the 13th) 

 the temperature was only 7" at the bottom, but the sahnity was 32''/oo- The 

 codfish seemed now to be scarcer out here. 13. September the boats of 

 Nyborg fished here for the first time greater quantities of herrings, in drift- 

 nets. Many eider-ducks liad eome, and a few cormorants were seen at 

 Sprogø. 5. November we again fished in the same place, with 600 hooks, 

 but no dogfish were found. It is thus no uncommon thing to catch many 

 dogfish in the Great Belt; but it seems, as if their occurrence is rather 

 accidental, wliich presumably may be explained by the supposition that tliey 

 are, to a great extent, migratory fish which scour tlie seas in shoals. 



On the Value of the Common Starfish as Manure. 



It has often been diseussed, particularly with respect to the Limfjord, 

 whether we should not try to destroj' the starfish (Asterius ruhens), because 

 they are noxious animals. They live to a great extent on the same little 

 white and red bivalves as the plaice, and waste, consequently, part of the 

 produce of plaice-flesh in the fjord. The starfish are so exceedingly nu- 

 merous up here that the question is of great importance for the economy of 

 the fjord, and they breed freely. Many tons of them, certainly, are caught 

 every year, particularly in seines and nets, but the fishermen throw them 

 out again, as soon as possible, generally in a state of full vitality. If the 

 starfish that are fished, were killed onboard, or carried to land, something 

 would be gaiued already. As I supposed they might possibly be of value 

 as manure, a quantity of them were sent to Professor V. Stein's laboratory 

 to be analysed. He writes: "In the condition in which the starfish were 

 when I received them, tiiey coutained: 



Water 58,9i p. c. 



Organic substances*) 23,3.s - 



Lime 7,-? p. c. 



corresponding to: 



Carbonate of hme 13,s8 - 



Potash (K., 0) 0,55 - 



Phosphoric acid (Pj O-) 0,55 - 



Other dissolvable substances 2,65 - 



Inorganic substances insoluble in acid.... O.is - 



Inorganic 



substances 



dissolvable 



in acid. 



Dry sub- 

 stances 

 41,09 p. c. 



100,00 p. c. 



Herein nitrogen 2,|,.j p. c. 



