FISHERY BULLETIN: VOL. 87, NO, 1 



Block 1 



Nl MM MM M^' M^' 



Natural Seagrass 



7.5 m 



TREATMENTS 



(6 (^ S (^ 



PA= LOW PERIMETER/AREA RATIO /^ CT~\ f"^ /-^ 



(all planted) <^ K±J KJJ i^J 



ch & (£> &) 



(§) S (3) (^ 



Nl= NATURAL INTERIOR 

 NE= NATURAL EDGE 



L 



HPA^HIGH PERIMETER /AREA RATIO 

 (plots planted) 



B = BARE, UNPLANTED 



PLANTING UNIT 



Figure 2.— Map view of the study site with the dredge island to the northeast. Each treatment is 7.5 m 

 on a side and each plot is 1.5 m on a side. 



a fine-tooth hacksaw blade to indicate the type of 

 treatment. 



The first placement of bay scallops was done dur- 

 ing high tide on 20 February 1986. Based on natural 

 scallop density surveys conducted in November 1985 

 showing densities of ~2.0 scallops/m-, we stocked 

 5 bay scallops/2.25 m- plot. The 5 scallops were in- 

 dividually placed next to 5 randomly selected plant- 

 ing units out of the 16 in the plot. Thirty-four days 

 after deployment, scallop surveys were conducted 

 over four days from 26 to 30 March 1986 (survey 

 I). The survey was conducted by placing a 7.5 m x 

 7.5 m grid made of Ys" nylon line, subdivided into 

 25 sections (2.25 m^ each) over an experimental 

 unit. Bay scallops were located by systematically 

 searching the substrate and grasses by sight and 

 touch while snorkeling. Within each 2.25 m^ sec- 

 tion, the efficiency of this method in recovering bay 

 scallops <15 mm was untested, but recovery of bay 

 scallops in the size range that was marked was 100% 

 in three separate field trials. All unmarked bay 

 scallops were measured to the nearest 0.1 cm on 

 site, recorded by the section in which they were 



found, and replaced after measuring. Marked bay 

 scallops were identified and recorded in the same 

 manner. 



Due to low recovery of marked bay scallops from 

 the transplant and bare areas over the 34-38 d 

 period, a second survey (survey II) was initiated 

 which excluded the natural seagrass beds. This sec- 

 ond set of scallops was identified with waterproof 

 pens and notching, but both shells were notched in 

 the event the shells became separated after death. 

 Forty-five bay scallops, five in each of nine plots, 

 were released in LPA, HPA, and B treatments 

 in blocks 1,3, and 5, but not in any natural treat- 

 ments, on 30 March 1986 and surveyed 8 days 

 later. 



RESULTS 



General observations during February through 

 April revealed a variety of shorebirds, especially 

 laughing gulls, brown pelicans {Pelecanus occiden- 

 talis), and cormorants {Phalacrocorax olivacev^), 

 frequenting the dredge island. Seagulls dropped 



192 



