ECHIUROIOEA 



ECHIURUS ECHIURUS ALASKENSIS 

 ANNELIDA 



0LI60CHAETA (MICRODRILE) 



ARENICOLA PUSILLA 



NEPHYTES CAECA 



NEREIS SP 



CHEILONEREIS SP 

 ARTHROPOOA 



DETONELLA PAPILLICORNIS 



NEOSPHAEROMA OREGONENSIS 



IDOTHEA WOSNESENSKI 



6AMMARIDAE 



HEMISRAPSUS OREGONENSIS 



PAGURUS SP 



BALANUS SP 



CHELONETHIDA 



EPHEMEROPTERA -IRON SP 



PLECOPTERA- CHLOROPERLIDAE 

 MOLLUSCA 



MYTILUS EDULIS 



MACOMA NASUTA 



MACOMA BALTHICA 



CLINOCAROIUM NUTTALLI 



PROTOTHACA LACINIATA 



SAXIDOMUS GI6ANTEUS 



MYA TRUNCATA 



ACMAEA SP 



LITTORINA SP 

 ECHINODERMATA 



ASTERIAS SP 

 VERTEBRATA 



ANOPLARCHUS PURPURESCENS 



PHOLIS LAETUS 



TIDEFLAT 



_L 



MIDDLE SLOUGH 



J_ 



_L 



J L 



_L 



MAIN STREAM 



li_L 



J L 



J L 



II 9 7 5 3 

 TIDE LEVEL (FEET) 



II 9 



Figure 5. — Distribution of organisms by tide level, Olsen Creek drainage, 1961. 



At each tide level an approximate area of 

 400 square feet was paced off, and from a 

 table of random numbers 10 sample sites, 

 each 1-foot square, were selected. In the 

 exposed tideflat area, organisms visible from 

 the surface and from 6 to 8 inches below the 

 surface were collected by hand. In collecting 

 stream samples each site was dug and all 

 loosened organisms were washed into a screen 

 of IZ meshes to the inch placed just down- 

 stream from the site. Although more thorough 

 collecting methods would yield more species, 

 the present collection was probably repre- 

 sentative of the larger, most abxindant inter- 

 tidal residents. 



The tideflat between the two streams yielded 

 the greatest number of species. Middle Slough 

 the next greatest, and the main stream the 

 least. The greater volume and velocity of the 

 water and the spawning activity in the main 



stream could have contributed to the scarcity 

 of bottom inhabitants. 



Large numbers of unidentified microdrile 

 oligochaetes were found between the 11- and 

 2-foot levels of both streams. Fucus, the 

 dominant alga in each habitat, was found from 

 the 9- to 2-foot tide levels on the tideflat, 

 from the 7-foot to level in Middle Slough, 

 and from the 2-foot to level in the main 

 stream. Eelgrass ( Zostera ) was nnost abundant 

 at the 1-foot to tide level in each habitat. 

 Fry and fingerling coho salmon ( Oncorhynchus 

 kisutch ) and Dolly Varden ( Salvelinus malma ) 

 were found in all the intertidal streanns above 

 the 7-foot level. A few fingerling chum and 

 pink salmon were found in Middle Slough and 

 Little Creek during July. Coastrange sculpin 

 ( Cottus aleuticus ). Pacific staghorn sculpin 

 ( Leptocottus armatus ), and threespine stickle- 

 back ( Gasterosteus aculeatus ) were more 



