Astacidae 237 



Reference 

 For the feeding of crayfish see note on p. 49. 



CULTURE METHODS FOR BRACHYURA AND ANOMURA 



Josephine F. L. Hart, Pacific Biological Station 



THE methods of successfully maintaining and rearing crabs and 

 hermit crabs in the laboratory are not entirely dependent on the close 

 simulation of natural conditions, but on careful feeding and preservation 

 of hygiene during the progress of the experiment. 



Immediately on collection of the specimens, a mature male and female 

 should be placed together in a container. The larger crabs are best 

 preserved in live boxes or aquaria with circulating seawater, but the 

 small ones may be placed in shallow dishes, approximately 3 liters in 

 capacity, in which cases the water should be changed daily. 



It has been observed that many species of crabs, scavengers, carnivo- 

 rous and herbivorous feeders, will live under such conditions, when fed on 

 finely minced, fresh, clam muscle. It is probable that there are more 

 suitable foods (Orton, 1927), but in the instances that have come under 

 direct observation this diet has been found satisfactory. 



If sand or other natural bottom material is placed in the jars, detritus, 

 rotting food, and feces may not be effectively removed, and the accumu- 

 lated decomposition products tend to cause pollution and the subsequent 

 growth of detrimental bacteria and Protozoa. If the specimens are kept 

 in a live box or a barren aquarium with running water, these factors are 

 negligible. If the individual dishes or plunger jars (Brown, 1898; 

 Lebour, 1927) are used, they should be cleaned daily about three hours 

 after feeding. During the cleaning process, the animals should not be 

 handled, in order to avoid the possibility of physical damage to them. 



Copulation has been observed to take place under these conditions in 

 Scleroplax gramdata and Lophopanopeus bellus, followed by the de- 

 position of the eggs. The females were then isolated in separate con- 

 tainers and the development of the eggs observed. 



The larvae, upon hatching, swim to the surface of the water and 

 should be removed with a pipette and placed in large beakers of freshly 

 obtained seawater, which may be aerated by stirring with a glass rod. 

 The larvae should be examined daily, fresh water and food given, and 

 all the dead material and sloughed skins removed. This is most easily 

 accomplished by transferring the active larvae to a fresh container, 

 already supplied with food material. 



The chief difficulty encountered in rearing decapod larvae is the 

 maintenance of a constant supply of suitable living food. Many of the 

 forms eaten in the natural state, when placed in laboratory conditions, 

 soon die and their decomposition products in the water kill the larvae. 



