moves farther offshore into deeper water. Philllpps (19^6) 

 reported that the New Zealand porbeagle lives in depths of 

 1200 feet, although young specimens are taken regularly in 

 180-300 feet. Strasburg (1958) took L. ditropis at depths 

 of 160 to 500 feet in pelagic longlinlng operations. Toward 

 warm-temperate regions the porbeagles normally descend to deeper 

 levels. 



The bonito shark, according to the relatively few records 

 available, does not inhabit any particular depth between the 

 surface and 5OO feet (Strasbiorg, 1958) • The roako apparently 

 lives in shallower depths than its relatives and has even been 

 known to beach itself while pursuing prey in shallow coastal 

 waters (lllingworth, I961). 



The white shark reportedly has been taken as deep as 4,200 feet 

 (Bigelow and Schroeder, 19^8), but it has been reported most often 

 in surface waters and has been known to enter extremely shallow 

 coastal waters. 



FOOD 



The most important food source for these sharks is fishes. 

 The species eaten are varied, generally depending upon the region 

 inhabited by the shark. For example, herring, pilchard, and ground 

 fish, such as the gadoids and flounders, were taken most often by 

 Lamna nasus in the western Atlantic. It also feeds on other small 

 sharks, such as dogfish, and on squid. Sano (1960) reported on the 

 significance of L. ditropis as a predator on salmon, and stomachs 

 examined by him contained Oncorhynchus nerka , 0. keta, 0. gorbuscha , 

 and 0. kisutch . Other fishes also were recorded, including Alepi - 

 saurus borealis , Anotopterus pharao , Pleurograjmius monopterygius , 

 Eumicrotremus orbis , and Theragra chalcogr^rnma . 



Many kinds of fishes are taken by the mako, but the smaller 

 schooling fishes, such as scombroids and clupeoids, are most 

 commonly ingested. Makos are reported to feed on laxger fishes too, 

 such as snappers and yellowtail. A 120-pound swordfish (with sword) 

 was found in one specimen and I50 pounds of swordfish flesh in the 

 stomach of another. 



The white shark has the most varied diet among the lamnids. 

 The stomach remains of the small specimens taken off the Scripps 

 Pier included cinistaceans, squid, Mustelus californicus , and 

 S cojrpaeni chthy s marmoratus . Elsewhere, larger specimens have 

 contained sharks up to 7 feet long (one contained two adults of 



- 9 



