154 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 9 



the commoner, floats, the latter sinks and is hard to locate. A fine-meshed 

 dipnet is always a necessity for securing fishes that sink or for catching 

 those that would otherwise make off to hide and die in holes among rocks. 

 Finally, some blennies often leave the water at the first whiff of poison, 

 and skip over the rocks to other pools. 



Although derris is used most effectively in pools, the senior author 

 also used it with considerable effect on open rocky coasts where the surf 

 was not great. While large quantities must be used, and the effect is 

 soon dissipated by surging waves, many fishes will become more or less 

 affected and can be caught with the dipnet before they escape or are 

 carried away. Dr. L. P. Schultz and Dr. W. M. Chapman have recently 

 used derris in large quantity and with great effectiveness upon the coral 

 reefs of the central Pacific. As they have explained it to the senior 

 author, liquid derris-mud was carried out to near the outer edge of the 

 reef in large containers, at low tide, and was poured liberally along a sec- 

 tion of the reef during the intervals between the breaking of the waves. 

 The waves not only wash the solution over the surface of the reef towards 

 the shore, but also carry dead and dying fishes shoreward. For opera- 

 tions as extensive as these, large quantities of derris powder must be taken 

 to the field by the collector, in tight 25 or 50-gallon steel drums; the 

 drums may then be used to preserve and pack the formalin-preserved 

 fishes for shipment home. This type of collecting is expensive so far as 

 the derris is concerned, but results in collections of such completeness and 

 magnificence as to make previously used methods of obtaining the smaller 

 shore or reef fishes seem a pure waste of valuable time. This is true 

 especially when the ichthyologist goes on a long journey to reach his 

 collecting locality. The cost of the derris is small compared to traveling 

 expenses. Naturally, preservative and containers commensurate with the 

 amount of derris to be used must be at hand. If proper care is used in 

 selection of collecting places, at least one gallon of container space should 

 be allowed for the preserved, wrapped, and packed smaller fishes resulting 

 from the use of every pound of derris dust expended. It is possible that 

 the rotenone extract now supplied commercially would greatly reduce the 

 bulk of poison the collector must take with him, but we know of no one 

 who has used it in ichthyological collecting. 



Commercial rotenone fish poisons may also be used with great effect 

 in fresh-water fish collecting. Their effect (using the fresh poison) has 

 already been described by Eigenmann (1912, pp. 30-58) and by Eigen- 

 mann and Allen (1942, pp. 28-32). Eigenmann's account of taking 60 

 species of small fishes in an insignificant trickle of water on Gluck Island, 



