Govoni and Olney: Predation on fish eggs by Mnemiopsis leidyi in and around Chesapeake Bay 



185 



FLOOD EBB SLACK EBB FLOOD 



DUSK MIDNIGHT DAWN NOON DUSK 



Or 



5- 



10 



I I I I I 



10 100/10 100/10 100/10 100/10 100 



NUMBERS • m" 3 



Figure 3 



Temporal hydrographic sections (temperature, salinity, sigma-t) and den- 

 sities (numbers/m 3 ) of Miiemiopsis leidyi and fish eggs at station E4 at the 

 mouth of Chesapeake Bay. 



Table 1 



Potential predation of the lobate ctenophore 

 Mnemiopsis leidyi on fish eggs at the mouth of 

 Chesapeake Bay. Values are the end points of 

 the range over five diel intervals. 



Potential predation rate 

 (eggs/m 3 x day) 



Strata 



Station El 



Station E4 



Surface 

 Pycnocline 

 Below 

 pycnocline 



0.1-14.7 



1.6-4.4 



0.5-3.8 



21.0-174.3 

 0-68.8 

 0-25.1 



that spawn in low-salinity surface waters of well-strati- 

 fied water columns may afford protection of their eggs 

 from ctenophore predation. Estuaries typically fluc- 

 tuate between stratified and unstratified conditions as 

 a result of lunar periodicity and meteorological forcing. 

 A survival advantage may be afforded by spawning in 

 association with the predator free surface waters of the 

 Chesapeake Bay plume. 



Acknowledgments 



Laboratory, field, and computer assistance 

 was provided by J. Brubaker, B. Comyns, 

 P. Crew, J. Fields, H. Johnson, E. Maddox, 

 and J. Posenau, all of the Virginia Institute 

 of Marine Science. A.J. Chester, J.H. 

 Cowan, J.C. McGovern, and J. A. Musick 

 reviewed the manuscript. This study was 

 supported by a grant from the National 

 Science Foundation (OCE-850144). 



Citations 



Alldredge, A.L. 



1984 The quantitative significance of gelatinous 

 zooplankton as pelagic consumers. In Fasham, 

 M.J.R. (ed.), Flows of energy and materials in 

 marine ecosystems, p. 407-433. Plenum Press, 

 NY. 

 Bailey, K.M., and R.S. Batty 



1983 A laboratory study of predation by Aurelia 

 aurita of larval herring (Clupea harengus): Ex- 

 perimental observations compared with model 

 predictions. Mar. Biol. (Berl.) 72:295-301. 

 Bailey, K.M., and E.D. Houde 



1989 Predation on eggs and larvae of marine 

 fishes and the recruitment problem. Adv. Mar. 

 Biol. 25:1-83. 

 Bishop, J.W. 



1967 Feeding rates of the ctenophore, Mnemiopsis leidyi. 

 Chesapeake Sci. 8:259-264. 

 Boicourt, W.C., S.-Y. Chao, H.W. Ducklow, P.M. Gilbert, 

 T.C. Malone, M.R. Roman, L.P. Sanford, J.A. Fuhrman. 

 C. Garside, and R.W. Garvine 



1987 Physics and microbial ecology of a bouyant estuarine 

 plume on the continental shelf. EOS-Riv. Immunol. Immuno- 

 farmacol. 68(31):666-668. 



