MASTERS OF THE WATER-BONY FISHES 



281 



tide and acquire an effective memory of the general features of the topography 

 of a Hmited area around the home pool which they are able to utilize when 

 locked in their pools at low tide." 



Tavolga (1954) has studied the complex breeding behavior of this fish, which 

 seems to be fairly typical of gobies and also of blennies. The male fishes are 

 vigorous in their protection of a home territory, which is usually a small area 

 surrounding some crevice or hole in the rocks. They may even choose a shell 

 or tin can as a home and can be captured by placing empty cans in waters where 

 gobies are found. Usually they show colors that somewhat match their environ- 

 ment, but at times of fighting between males or mating, dark, background- 

 contrasting colors are put on. Fighting males also show "throat-puffing, gasping, 

 quivering, butting, and biting movements." After a site is chosen, it is cleaned 

 bv the male. He then approaches the female with a vibrating motion of the fins 

 and tail, and both male and female change colors with their emotional state. 

 The female enters the nest cavity twelve to twenty-four hours before laying her 

 15,000 to 18,000 eggs, a feat that takes three to nine hours. The female departs, 

 and the male guards and fans the eggs. Females can lays eggs every seven to 

 sixteen days. With a fall in water temperature,, the male will brush the eggs 

 vigorously to induce hatching five to seven days after the eggs were laid. 

 Tavolga says, ". . . the natural temperature stimulus may be the inundation 

 of the tidepool bv cooler water by a rising tide. This would insure a wider 

 dispersal of the pelagic larvae by the tidal water current." 



Similar Species: Other small gobies are found north to Cape Cod. On the West 

 Coast there are numerous similar species found south of Vancouver. Most 

 West Coast forms are small (up to 3 inches) and are most common in bays 

 and on mud flats. 



sleeper: 



Dormitator maculatus 



Size: The largest goby, up to possibly 2 feet. Mostly under a foot. 



Distrihution: West Indies to South Carolina. 



Identification: The mulletlike shape, large size, and gobylike fin pattern 

 identify it. Its colors are extremely varied. 



Habits: The sleeper can live in salt, brackish, and fresh waters. Like the 

 killies, it can stand a wide range of pollutions and temperatures, so it makes a 

 good aquarium pet. In spite of the large size, its habits are like those of the 

 smaller gobies. 



Fig. 158. Sleeper. 



