FISHERY BULLETIN: VOL. 79, NO. 4 



low, followed by the decade 1947 to 1958 when the 

 industry was at its peak. After 1958 the industry 

 almost collapsed, and it has not recovered. The 

 harvest of oyster by tongs was much smaller, but 

 somewhat similar through 1947. After 1947 there 

 was no resurgence. 



Maurer et al. (1971) made a survey of the oyster 

 industry in Delaware Bay in 1968 and 1969. 

 They found that Delaware Bay beds were badly 

 depleted, but certain rivers in the vicinity showed 

 potential as seed areas. One planted bed showed 

 promise, suggesting that with proper manage- 

 ment Delaware Bay could be rehabilitated and 

 again produce oysters. The incidence of Minchinia 

 nelsoni probably always was lower in the rivers 

 than in the bay, and incidence on Delaware Bay 

 beds was not as high as in the mid-1960's. 



The hoped for increase had not occurred up to 

 1978, suggesting that no one was willing to take 

 the risks, or had tried and failed. The present poor 

 condition of oyster beds in Delaware Bay is caused 

 by M. nelsoni, aggravated by general degradation 

 of the environment. It is possible, but not certain, 

 that with proper care the grounds could be re- 

 stored to production. 



Clam Dredges 



Dredges were used to harvest hard clam and 

 surf clam in Delaware. The first hard clam taken 



by dredge was recorded in 1901, but substantial 

 numbers were not taken until 1929, when 360 t 

 (nearly 800,000 lb) were caught (Figure 30). 

 Catches dropped to much lower levels in 1931 

 and 1932, and remained fairly low until after the 

 Second World War. This probably was at least 

 partly caused by stabilization of Indian River 

 Inlet, which raised the salinity in the Delaware 

 Bay, and proved favorable for hard clam. Land- 

 ings have been quite variable since, and the last 

 hard clam listed as taken by this gear was in 1969. 

 Another short-lived fishery was dredging 

 for surf clam, which began in 1956 and produced 

 moderate catches until 1962, then ceased. Land- 

 ings again were reported in 1969, peaked at 3,800 1 

 ( >8 million lb) in 1970, remained fairly high until 

 1974, but ceased in 1976. The fluctuations largely 

 reflected where the boats were operating, as dis- 

 cussed earlier in the surf clam section. 



Crab Dredges 



Blue crab was first recorded as caught by 

 dredges in Delaware in 1932. Catches were rela- 

 tively small until the 1950's, when 1,700 t 

 (>3.5 million lb) were recorded in 1950 and 1951 

 (Figure 31). Catches then dropped sharply, peaked 

 again in 1957 at 770 t (about 1.7 million lb), and 

 dropped to a very low level from 1964 to 1973, after 

 which they picked up again but at a lower level. 



SURF CLAM 



00 O 

 Q I- 



CO tr 



O LJ 



1 ^ 



O 2 



UJ o 



if 





o 



CO 



Figure 30.— Commercial landings 

 by hard clam dredges in Delaware, 

 1901-69. and by surf clam dredges 

 1956-75, and numbers of units of gear 

 licensed. 



596 



