Paper 17 



during August and September was in ^968 ^ with 1971 second/' the 

 years of fall fish kills. fJone of the cases of early spring and 

 late fall kills occurred in the same year. 



Included in the data set of bottom water oxygen concentration 

 were some values from February and June of 1968 and from f^arch of 

 1971. At these times/ the bottom water oxygens were above or 

 equal to the average trend values/ implying that the low oxygen 

 accompanying the fish kills did not result from eari^ stratifi- 

 cation. 



CONCLUSIONS 



Stratification that develops in the Shelf Uaters off New Jersey 

 in spring and persists through sjmmer/ along with limited 

 exchange with offshore waters/ tends to develop an almost 

 stagnant water layer along the bottom. During this period of 

 near stagnation/ bottom oxygen concentrations typically decline 

 until fall/ when cooling at the surface leaos to overturning and 

 replenishment of dissolved oxygen. Conditions that would 

 lengthen the season of stratification/ and thereby stagnation/ 

 are considered to be the principal elements that would set the 

 stage for generation of anoxic conditions. 



The pe 

 a r r i V a 

 of i nc 

 ( Late 

 by t he 

 kills 

 fall a 

 the t 

 pot ent 

 c cur r 

 h i ghe s 

 in 19 

 p ro Ion 



n oo 

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 rease 



i ni t 

 se de 



r epo 

 r r i ve 

 wo m 

 ia I i 

 ed i 

 t dis 

 76/ 

 ged s 



of s 

 ap 

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 i at i 

 f in i 

 rted 

 d La 

 ost 

 nst a 

 n t 

 cha r 

 i mp I 

 t rat 



t rat i 

 ring 

 ring 

 on of 

 t i ons 



i n 

 t e se 

 re ce 

 nces . 

 he s 

 ge an 

 ying 

 i f i ca 



f i cat i 

 (early 

 river 



coo I i 

 / sp r i 

 the tw 

 ven t i 

 nt ca 

 Both 

 ame y 

 d warm 



that 

 t i on . 



on c a 

 warm 

 di sch 

 ng) . 

 ng be 

 V mos 

 mes ( 

 ses/ 



an e 

 ea r . 

 ing r 

 that 



n be 

 i ng 

 a roe 



Ove 

 gan 

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 Jith 



197 



ar Ly 



Fo 



at es 



yea 



pro 

 comb 

 ) or 

 r t h 

 earl 

 cent 



f is 

 1 an 



sp r 

 r t 



for 

 r H a 



longe 

 i ned 



the 

 e las 

 y f i V 



case 

 h ki I 

 d 196 

 i ng a 

 he 30 



an e 

 s the 



d by 

 with 

 Late 

 t 30 

 e t 



S/ 1 



Is a 

 8)/ 

 nd a 

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 ar ly 

 mos 



eit 

 ear 

 a r r 

 yea 



ime s 



976 



gain 



for 

 lat 



peri 

 spr 



t ex 



her t 

 I y c 

 i va I 

 rs (1 

 (wi 

 and 1 

 repo 

 a tot 

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 od of 

 ing 

 t reme 



he e 

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 of 



947- 

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974) 

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rec 

 occu 



ca s 



a r ly 

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 fall 

 76)/ 

 fish 

 and 

 i n 

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 ever 

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Bathymetric differences on the continental shelf seem to cause 



the effects of stagnation to be more intense off New Jersey than 



in adjacent ihelf Waters off Long Island and the Delmarva 

 Peninsula. 



295 



