a multiple spawner (Freeman and Turner 19b2). There is no information 

 available regarding distribution of larval and juvenile stages. 



In addition to cannibalism, tilefisn food items include crustaceans, 

 molluscs, annelids, and a variety of fish species that are indigenous to the 

 same depth zone. They are prey to large bottom-dwelling sharks, man, and 

 larger tilefisn (Bigelow and Schroeder 1953). 



An invasion of unusually cold water during 1882 caused a major kill of 

 tilefish. An estimated 500 million tilefisn were seen floating by passing 

 ships (Collins 1884). It is difficult to estimate tilefish population size 

 because of their patchy distribution. Temperature variations also influence- 

 their distribution and abundance. There has been no noticeable change in 

 catch rate by commercial boats, although the fishing effort has recently 

 tripled (Freeman and Turner 1977). 



For additional information regarding tilefish biology and the commercial 

 fishery, see Turner et al. (1983). 



Bottom Trawl Survey Results 



The cumulative spring and autumn distributions over the time series are 

 shown in Figures 17.1 and 17.2. Few tilefish have been caught on NMFS 

 resource assessment surveys because the number of deepwater stations occupied 

 were few, and the fish's close asociation with holes or "burrows" into which 

 they can escape make them unavailable to the roller rigged trawl. The few 

 fish that were caught have all been taken beyond the 100 m contour with no 

 apparent seasonal difference in distribution. 



The mean weight and number per tow summaries (Figures 17.3-17.5) are of 

 little statistical value since so few fish wer- caught. 



Length frequencies for strata sets, arrangec. by season, are shown in 



389 



