SECT. 3] ORGANIC TRANSPORTATION OF MARINE SEDIMENTS 783 



and Latif, 1959, and included references). Shells, coral, and calcareous algae are 

 usually present aniong the stomach contents of parrot fish {Scams), surgeon 

 fish (Acanthurus), trigger fish (Melichthys), and puffer [Arothron) from Pacific 

 islands and the Red Sea. When frightened, the fishes defecate clouds of the 

 material comminuted to sand and silt grain size. The great role of fishes in 

 producing fine-grained sediments in lagoons of coral reefs has scarcely been 

 recognized. According to Bardack (1961) such coral-browsing fishes at Bermuda 

 ingest about one ton of calcareous material per hectare per year. 



Shallow-water fishes of non-calcareous areas also transport stones. According 

 to Conrad Limbaugh (Scripps Institution of Oceanography, in litt.) cabezone 

 (Scorpaenichthys) carries stones in its stomach in shallow water (less than 10 m). 

 The stones range up to 10 cm in diameter and weigh as much as a kilogram. 

 Possibly these stones are transported seaward to the 100-m depth limit of this 

 fish. Halibut, a bottom-living fish generally in deep water, was once noted by 

 Thompson (1919) to contain a stone weighing about one kilogram, but its pre- 

 sence was ascribed "to reckless eating, not foresight". According to J. E. Fitch 

 (California State Fisheries Laboratory, Terminal Island, i7i litt.) many other 

 bottom-living fishes also carry gastroliths. Among them are flounders, sculpins 

 and rock cods. Others, which live just above the bottom, sheepshead, ling cod 

 and ocean whitefish, also sometimes carry them. R. V. Vaughan (San Diego, in 

 litt.) stated that about 60% of the first arrivals in southern California of the 

 pelagic albacore tuna {Thunnus alalonga) contain stones. Most are granitic or 

 basaltic types, rounded and polished, about one cm in diameter. Aggregate 

 weights range up to about 100 g. Later in the season gastroliths appear to be 

 rare; in fact, they have not been recorded among the thousands of tuna stomachs 

 examined by personnel of the California State Fisheries Laboratory. Some 

 bottom-living freshwater fishes have the same habit, and, according to R. J. 

 Miller of Long Beach State College {in litt.), 8.2% of 146 specimens oi Cottus 

 beldingi from Lake Tahoe, California, contained stones. 



In addition to carrying stones as gastroliths, some fishes carry them for other 

 purposes. Skates and rays, for example, often cover themselves with sand, 

 presumably for concealment; when they swim away some of the sand is 

 carried for tens of meters. According to Limbaugh, pile perch (i)amaZ^cA^%s vacca) 

 at Guadalupe Island, off Mexico, carry flat pebbles in their mouths, "presumably 

 as an aid for crushing shellfish". He also reported that jawfishes in the Bahama 

 Islands line their burrows with pebbles, and that during excavation of burrows 

 under rocks, fishes, lobsters, crabs, shrimps, and octopi carry small stones for 

 short distances. Octopi in fact are known to carry pebbles for tens of meters 

 and have been reported to drop stones into clams and oysters to prevent closure 

 (Lane, 1957, pp. 69-72). 



Probably the bulk of stone transportation by fishes occurs in coral reef areas, 

 but some exists in other shallow-water coastal regions. Doubtless, fishes have 

 had similar habits during most of post-Ordovician times, though no observations 

 are available of fossil fish gastroliths. A distant relative, the Mesozoic reptile, 

 Plesiosaurus, however, is known to have carried gastroliths (Shimer, 1924, 



