360 NATURAL HISTORY OF HAWAII. 



very probable that most of them were built by the forced labor of the common 

 people. 



The ponds are found principally in the bays indenting the shores of the 

 islands, the common method of construction having been to build a wall of 

 lava rock across the narrowest part of the entrance to a small bay and use 

 the enclosed space for a pond. They were also built on the seashore itself, the 

 wall being built out from the shore in a half circle. 



Ponds vary in size from small ones of less than an acre in extent to the 

 unusually large one at Moanalua, on Oahu, which encloses over five hundred 

 acres. There are as many as a hundred and sixty of these ponds indicated on 

 the maps of the islands. Of this number perhaps one hundred are still in use. 

 The catch of ama-ama from the ponds of the islands in 1905 was 430,000 

 pounds, valued at more than $87,000. 



The mullet that find their way to the market from these ponds are iden- 

 tical with those found in the markets of the United States, Japan, Chile and 

 even the Mediterranean and as far away as India. The average weight of the 

 mullet in the market is from one to three pounds, though they grow to two or 

 three times that size, attaining a length of twenty inches or two feet. 



They feed on organic matter, especially the minute plants contained in the 

 mud on the bottom in the shallow water along the shore. As they naturally 

 gather up a large quantity of indigestible matter, these fishes have the organs 

 of the throat modified into a filtering apparatus. They take in large quanti- 

 ties of mud and sand and, after apparently chewing it for a time, spit out the 

 indigestible portion. 



The awa ^" and the awa-aua ^'^ are also reared in large numbers with the 

 mullet in the ponds. They all enter the ponds when young through openings 

 left for the purpose in the stone walls. Owing to the protection furnished by 

 the walls, the mullets thrive and fatten rapidly and, sheltered from their 

 enemies, become stupid and blundering. 



CHAPTER XXVIII. 

 HAWAIIAN FISHES : PART THREE. 



Flatfish. 



The visitor at the Aquarium is sure to be interested and delighted with 

 the beautiful and graceful flatfish that, in general habits and appearance, re- 

 semble the butterfly-fish, but differ from them in having the dorsal fin drawn 

 out to form a beautiful white plume-like filament often six inches or more in 

 length. The species is known to the natives as kihikihi, but since it is a wide 



*' Chanus chanos. *^ Elops sniinis. 



