FISHERY BULLETIN: VOL. 80, NO. 2 



mained at sea. However, in the Delaware River 

 estuary Atlantic sturgeon between 800 and 1,300 

 mm were common and composed 62% of the 

 measured specimens from Delaware Bay and 

 48% of those from the lower tidal river. It is 

 possible that the Delaware River estuary is 

 utilized during a greater portion of the Atlantic 

 sturgeon's life cycle then is the Hudson. This may 

 be associated with the relatively unimpacted 

 condition of Delaware Bay and the lower Dela- 

 ware River as compared with the heavily indus- 

 trialized and degraded lower Hudson River 

 estuary. It is also possible that an Atlantic 

 sturgeon which has left the Hudson River may 

 utilize other estuaries, including the Delaware 

 system, during this portion of its life. Recapture 

 of tagged Hudson River sturgeon in the 

 Delaware River and more distant estuaries 

 (Dovel 1979) may substantiate this view. 



No specimens in spawning condition were re- 

 corded from the Delware River Estuary; most 

 reported were probably immature. Most Atlan- 

 tic sturgeon captured in the Delaware River 

 estuary were <112 cm TL minimum for mature 

 males and <200 cm for mature females reported 

 by Dovel (1979). Larger mature specimens are 

 almost certainly present in the estuary but are 

 not vulnerable to the small-mesh gear typically 

 fished by commercial fishermen and fishery 

 biologists. Even though spawning location could 

 not be ascertained it is perhaps signficant that 

 the smallest specimen recorded (128 mm) was 

 taken near Pea Patch Island, Del. (river km 101), 

 an area historically described (Borodin 1925) as 

 a principal spawning area for Atlantic sturgeon. 



This compilation of incidental catches and a 

 substantial body of anecdotal information sug- 

 gests that Atlantic sturgeon may be far more 

 abundant in the Delaware River estuary than 

 commercial catch statistics and the impressions 

 of other fishery scientists indicate (Hoff 3 ). The 

 reported scarcity of Atlantic sturgeon may be 

 more the result of not fishing the appropriate 

 gear in the right locations at the right times or of 

 not monitoring fishermen who are. A more 

 definitive status evaluation will require quanti- 

 tative investigation to determine population size, 

 mortality rate, age-specific fecundity, age at 



'James G. Hoff, Biology Department. Southern Massachu- 

 setts University, North Dartmouth. MA 02747. pers. commun. 

 July 1980. See also, Hoff. J. G. 1980. Review of present 

 status of the stocks of the Atlantic sturgeon. Acipenser 

 oxyrhynchus (Mitchill). Southeastern Massachusetts Univ.. 

 North Dartmouth, 136 p. 



first reproduction, and spawning time and loca- 

 tion. In any event, the value of incidental capture 

 records and anecdotal accounts should be recog- 

 nized and continued monitoring of available 

 sources is advisable. The potential for restora- 

 tion of the stock is high, based on the lack of 

 industrial development in the lower estuary and 

 the fact that as yet undammed, the Delaware 

 River still features relatively natural run-off and 

 river flow patterns. Pollution abatement 

 programs, particularly those involved with 

 improvement of dissolved oxygen levels in the 

 Chester to Philadelphia reach will undoubtedly 

 enhance this potential. 



ACKNOWLEDGMENTS 



We are grateful to Victor J. Schuler and Alan 

 W. Wells of Ichthyological Associates, Inc., for 

 their critical reading of the manuscript. Joseph 

 Miller of the U.S. Fish and Wildlife Service, 

 Richard J. Seagravesof the Delaware Division of 

 Fish and Wildlife, and Robert G. Howells of 

 Ichthyological Associates, Inc., supplied collec- 

 tion data for several specimens. We also thank 

 Robert G. Howells for drafting the figures and 

 Holly J. Jones for assistance with manuscript 

 preparation. 



LITERATURE CITED 



Beck, R. A. 



1973. Sturgeon— alive and well. Del. Conserv. 17(2):4- 

 6. 

 Borodin, N. 



1925. Biological observations on the Atlantic sturgeon 

 (Acipenser sturio). Trans. Am. Fish. Soc. 55:184-190. 

 Cobb, S. N. 



1900. The sturgeon fishery of the Delaware River and 

 Bay. Rep. U.S. Comm. Fish. 1899:369-380. 

 Daiber, F. C, and R. C. Wockley. 



1968. Annual Dingell-Johnson Report, 1967-1968. 

 Univ. Del., Newark, 35 p. 

 deSylva, D. P., F. A. Kalber, Jr., and C. N. Schuster, Jr. 

 1962. Fishes and ecological conditions in the shore zone 

 of the Delaware River estuary, with notes on other 

 species collected in deeper waters. Univ. Del. Mar. 

 Lab., Inf. Ser., Publ. 5, 164 p. 

 Dovel, W. L. 



1979. Biology and management of shortnose and Atlan- 

 tic sturgeon of the Hudson River. Final Rep., 53 p. 

 Freidersdorff, J. W., L. Lofton, and R. C. Reichard. 



1978. Performance report Delaware River Basin anad- 

 romous fishery study. U.S. Fish Wildl. Serv., 

 Rosemont, N.J., 34 p. 

 Martin Marietta Corporation. 



1976. Monitoring fish migration in the Delaware River. 

 Final Report - March 1976. Martin Marietta Corp., 

 Baltimore. 86 p. 



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