88 



SUMMARYo" None of the animals is conspicuously large or abundant. 

 The fauna has the appearance of a replaced one, with individual 

 niimbers sparse and perhaps at the fringe of their distributions. 

 The estimated volume of organic matter is 90 ml. 



Summary of Zone I^ western sector, numbers W-1 to 22» 



The sample from W-1 is from a shifting beach sand characterized 

 by sand worms, Nephtys callforniensls , a sand crab, Lepldopa myops , 

 and diversified smaller kinds. The Limit ed-Pollutlon-Fatina Is re- 

 presented by W=2, characterized by Nephtys caecoldes , Nothrla elegans 

 and other kinds of smaller polychaeteSo Species are limited in 

 number and sizso EchinodermS;, mollusks and smaller crustaceans are 

 either sparse or absento A Pollutlon°Toler ant-Fauna is represented 

 by samples from W-3 to 5^ and characterized by Increasing numbers 

 and kinds of species and larger sizes of individuals; present are 

 Glycera amerlcana , Marphysa nr. conferta . Nereis procera, and other 

 kinds of polychaetes, in addition to some smaller mollusks, and increas- 

 ing number of smaller crustaceans and some ophiuroids, or also smaller 

 individuals of Astropecten » 



The Limit ed°Enrlched°Fauna g representea by samples from W-6 to 12, 

 is considered limited for lacking some species known to occur in similar 

 areas that are not pollutedo It is enriched for having unusually high 

 numbers of Individuals (peaks of biomass). Thus, in one sample (W-7 ) 

 ophiuroids are represented by 3 species with 188 individuals, mollusks 

 by 23 species and 125 individuals, crustaceans by 19 species and 

 about 150 individuals, polychaetes by 46 species and more than 200 

 individuals^ or in all 7 major groups with 95 species and 760 individuals, 



The Unllmlted-Dlmlnlshed Fa\ina , represented by samples from W-13 

 to 19, has Increasing numbers of kinds, but diminishing peaks (or none) 

 of blomass. This area is further characterized by having bottoms that 

 are largely gravelly, rocky or rubblyo The current fauna has the 

 appearance of a replaced one^ with vestiges of a former one, re- 

 presented by bleached fragments of hydrocorals, brachiopods, larger 

 mollusks and other larger epifaunal kinds of animals. The species now 

 present are largely those in the sediments or capable of moving about. 



I SW-1 Stao 2992=55o In 60 feet, OPG took 0,5 cuft of hard packed 

 sandy mud. The screenings consisted almost entirely of polychaetes. 

 Polychaetes Include? 



Ampharete arctica - 1 



parasitic arabellld = 1 



Arlcldea spp. - more than 50 



cirratullds, including Chaetozone , Tharyx and perhaps others - 

 himdreds 



piopatra ornata - about 12 larger, in coarsely constructed tubes 



Glycera amerlcana - 1 larger and 1 smaller 



Haploscoloplos elongatus - 2 larger and several smaller 



Lumbrlneris cruzensis - several 



Lumbrlnerls , other species 



Nephtys caecoldes - 2 larger 



Nereis procera - more than 70, some undergoing epitoky In tubes 

 of onuphld 



