PAUL and FEDER: LITTLENECK CLAM IN GALENA BAY 



Table L — A description of the three study areas in Galena Bay, Prince William Sound. Description of the beach 



and its biota refers to appearance at low water. 



Item 



Shell Beach 



Eater Beach 



Indian Creek Flat 



Wave and wind exposure 



Longshore currents 



Study area: 

 Size (feet) 

 (m) 



Slope 



Substratum 



Freshwater drainage 



Flora and fauna 



Most exposed 



Obvious 



190 X 70 

 57.6 X 21.2 



6°47' 



Fine gravel for first few 

 centimeters overlying fme 

 sediment 



Minimal 



No Fucus; no Mytiliis 



edidis: Balanus spp. very 

 sparse 



Well protected 



Not obvious 



220 X 100 

 66.7 X 30.3 



6°3' 



Fine gravel intermingled 

 with large rocks scattered 

 over beach; fine sediment 

 closer to surface than on 

 Shell Beach 



Typically minimal; strong 

 outwash after persistent 

 rains dissects center of 

 beach 



Light cover of Fucus; mod- 

 erate cover of M. edulis; 

 Balanus cover over entire 

 beach 



Protected but exposed to 

 occasional rain squalls 



Not obvious 



900 X 900 

 272.7 X 272.7 



o°2r 



Mixture of gravel and fine 



sediment 



Located at mouth of permanent 

 stream; flat; dissected by 

 numerous tributaries 



Light cover of Fucus at upper 

 edge; moderate cover of 

 M. edulis; moderate cover 

 of Balanus. 



from each transect were made from a series of 

 stations, with each station defined by a 0.25-m- 

 (115 X 22 cm) frame. The sediment within 

 each station was sampled to a depth of 15 cm. 

 The first collection made along a transect 

 (Station 1) was positioned 1 m up the beach 

 from the location of the first P. staminea 

 encountered in a preliminary trench dug di- 

 rectly adjacent to the proposed sampling tran- 

 sect. The number of stations on a transect was 

 dependent on the width and slope of the beach 

 and the tidal range at the time of collection. 

 On the two gravel beaches all stations sampled 

 were contiguous; however, on the mud flat, 

 a much larger area was involved, and collec- 

 tions here were made at 5.75-m intervals. 



Utilizing reference points from a standard 

 tide table (U.S. Coast and Geodetic Survey, 

 1970), a hand level, and a stadia rod, the tidal 

 heights were determined for the midpoint of 

 each station. 



Prior to sampling, distribution of P. staminea 

 was determined by removing sediment in 2-cm 

 layers to a depth of 8 cm from selected plots 

 (36 X 15 cm) along each transect. Samples col- 

 lected were examined in the laboratory under 

 a 2 X lens for the presence of P. staminea, 

 and sediments from these samples were then 

 used for sieve analysis of grain-size distribu- 

 tion (Morgans, 1956). 



Vertical distribution studies indicated that 

 most of the smaller P. staminea (1.5 to 20 mm 

 in length) were restricted to the upper 2 cm 

 of sediment; thus, sampling was accomplished 

 in two steps at each transect station. The young 

 clams were collected with the upper 2 cm of 

 sediment; the larger clams were collected with 

 the remaining sediment. 



Each surface sample was washed through a 

 series of screens, the smallest mesh being 

 1.5- X 1.5-mm window screening. Screens of 

 3.5- and 6.5-mm- mesh were used for washing 

 deep samples. Seawater used for the washing 

 process was furnished by a portable Homelite 

 Pump (Model XL5).- The sediment trapped 

 in the finest screen was returned to the labora- 

 tory and examined for small individuals with 

 a2x lens. 



Standard measurements taken on all clams 

 were greatest length and height (width) (see 

 Fraser and Smith, 1928 for details on measure- 

 ment technique). In an older P. staminea an 

 increase in shell height is often apparent when 

 the increase in shell length is so small that 

 it is difficult to measure. Therefore, shell height 

 is the most sensitive measurement for describing 



- Reference to trade names does not imply endorse- 

 ment by the National Marine Fisheries Service. 



667 



