FISHERY BULLETIN: VOL. 87, NO. 1 



we sought to evaluate whether bay scallop, Argo- 

 pecten irradians, stocking could be conducted simul- 

 taneously with eelgrass bed creation. 



Under this approach, stocked adult bay scallops 

 would be used as a source of spat settlement in the 

 maturing eelgrass bed. Bay scallops often utilize eel- 

 grass meadows throughout their life cycle (Outsell 

 1930; Kirby-Smith 1970; Thayer and Stuart 1974). 

 During the postveliger stage of development, a bay 

 scallop attaches itself to submerged substrates such 

 as vegetation (eelgrass blades), shells, rocks, animal 

 tubes, or macroalgae. At approximately 10 mm in 

 shell width, the scallop detaches and settles onto the 

 bottom sediments to complete its life cycle; adult 

 sizes range between 5 and 7 cm (Outsell 1930; Kirby- 

 Smith 1970; Thayer and Stuart 1974). During its 

 lifespan (1.5-2 years), bay scallops feed upon phyto- 

 plankton (Peirson 1983) and detritus (Kirby-Smith 

 and Barber 1974), which are plentiful in eelgrass 

 systems (Thayer et al. 1975). If scallop stocking 

 could not be done concomitantly with bed creation, 

 natural recovery of the scallop population could be 

 substantially delayed. 



Our study was embedded in a larger, long-term 

 study of eelgrass restoration and faunal recovery. 

 In that study, eelgrass was transplanted onto sub- 

 tidal dredge material and monitored to determine 

 the rate at which these propagated areas attain 

 functional characteristics of adjacent, natural 

 meadows. 



In preparing for the bay scallop stocking study, 

 we observed in an independent scallop dredging 

 survey that scallop densities near the study site 

 declined from 2.0 to nearly 0/m- between Novem- 

 ber and January 1985. During this period, laughing 

 gulls, Larus atricilla, were seen dropping live scal- 

 lops, a common feeding activity for these birds 

 (Pearson et al. 1959), onto a dredge material island 

 adjacent to our study area. This suggests that the 

 gulls were at least partially responsible for the ob- 

 served decline in scallop densities. Because this por- 

 tion of the study was designed to include an evalua- 

 tion of developing eelgrass meadows as scallop 

 habitat, the close proximity of the dredge island and 

 the increased likelihood of high predation on the 

 scallops by gulls had to be considered in the assess- 

 ment. Oiven the decline in the natural scallop popu- 

 lation, possibly exacerbated by gull predation, we 

 utilized a mark and recapture technique to assess 

 stocking feasibility. 



The general objectives of the study were to com- 

 pare the capabilities of natural eelgrass, trans- 

 planted eelgrass, and unplanted areas in support- 

 ing a stocked adult bay scallop population as a means 



of enhancing recovery of a local fishery. Specifical- 

 ly, we sought to 1) examine the feasibility of seed- 

 ing adult scallops in newly transplanted eelgrass 

 beds; 2) relate scallop density in experimental plots 

 to a) the proximity of these plots to the dredge is- 

 land and b) any preferential migration from the 

 transplanted or unplanted areas to the adjacent, 

 natural eelgrass beds; and 3) control for adult 

 scallop recruitment by comparing the densities 

 of naturally occurring scallops in natural and 

 transplanted eelgrass beds of two spatial arrange- 

 ments, as well as in unplanted plots within the study 

 site. 



METHODS 



The study site (long. 76°32'W, lat. 34°40'N, Fig. 

 1) was located at the southern end of Core Sound 

 and northwest of Cape Lookout, NC. Specifically, 

 the experiment was conducted off the southwest 

 side of a dredge material island in relatively shallow 

 waters (0.15 m at low tide and 1.0 m at high tide). 

 The island was originally created 10 years before 

 the study with maintenance dredging deposits added 

 every 2-3 years. The overall study site covered 4,556 

 m^, which was divided into five separate blocks ex- 

 tending out from the island (Fig. 2). For this study 

 on the scallops, only blocks 1, 3, and 5 were utilized. 

 Each block contained five different experimental 

 units which were 7.5 m on a side (56.25 m^). An ex- 

 perimental unit was separated from adjace'-* units 

 by a 7.5 m corridor. The five treatments for each 

 experimental unit were as follows: 1) natural in- 

 terior eelgrass (NI, >15 from unvegetated sub- 

 strate), 2) natural eelgrass bordering unvegetated 

 substrate (NE), 3) low perimeter to area (LPA) 

 eelgrass transplant arrangement (see below), 4) high 

 perimeter to area (HPA) eelgrass transplant ar- 

 rangement (see below), and 5) bare (B), unplanted 

 dredge material. Although positioning of the two 

 natural treatments were fixed, the other three 

 treatments were randomly assigned to the remain- 

 ing three experimental units within each block. 



Each experimental unit contained eight plots (2.25 

 m-), which were consecutively located around the 

 perimeter of the experimental unit (Fig. 2). These 

 eight plots were designated to accommodate eight 

 faunal sampling periods for the parallel study of 

 fishery habitat establishment. The two transplant 

 arrangements had different perimeter to area ratios 

 in order to examine the refuge value of large, un- 

 broken seagrass cover versus patchy cover. The 

 LPA treatments had eelgrass planting units 

 throughout the 7.5 m x 7.5 m area, whereas HPA 



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