FISHERY BULLETIN: VOL. 75, NO. 4 



TABLE 4. — Calculated values for regression equations describ- 

 ing the total length (TL in millimeters)-weight (W in grams) 

 relationship and the total length (TL in millimetersl-standard 

 length (SL in millimeters) relationship for summer flounder 

 from Delaware Bay. 



'This includes 20 juveniles from North Carolina. 



they stated that males were slightly heavier than 

 females on an equal length basis. We found no real 

 difference between the weights of equal sized 

 males and females in Delaware Bay, nor did El- 

 dridge (1962) for fish off Virginia. Twenty fish 

 from North Carolina were included in our total 

 length- weight relationship so we could have some 

 data points from fish in age-groups and 1. 



GONAD DEVELOPMENT 



Summer flounder gonads were examined from 

 1966 to 1968 for size and the ovaries for the pres- 

 ence of eggs. Gonads were small and flaccid from 

 April through mid-August. From mid-August 

 through November, the gonads began to enlarge 

 or mature, and the ovaries contained eggs up to 0.4 

 mm in diameter. Murawski 4 stated that the size of 

 mature eggs is 1.0 to 1.1 mm. There was never 

 more than one-third of any catch during the fall 

 with ripening gonads, and no mature fish were 

 caught from December through March. We con- 

 cluded that fish leave the bay as they ripen, sup- 

 porting reports that summer flounder spawn after 

 moving offshore during the winter. The smallest 

 male taken with ripening testes was 30.5 cm, and 

 the smallest female with ripening ovaries was 36 

 cm. These observations agree with those reported 

 by Eldridge (1962) who stated summer flounder 

 become sexually mature at age 3. 



FOOD PREFERENCE 



Stomachs from 131 flounder, ranging in size 

 from 31 to 72.5 cm, were examined under a dissect- 



4 Murawski, W. S. 1966. Fluke investigations. N.J. Fed. Aid 

 Proj. F-15-R-7 (Completion Rep. Job No. 3). N.J. Dep. Conserv. 

 Econ. Dev., 24 p. 



ing microscope, and 57% of them contained food. 

 Food items found, listed in order of percent fre- 

 quency of occurrence were: sand shrimp (Crangon 

 septemspinosa , 4:19c ), weakfish ( Cy nose ion regalis, 

 339c ), mysid (Neomysis americana, 20%), anchovy 

 {Anchoa sp., 7%), squid (Loligo sp., 4%), silverside 

 (Menidia menidia, 1%), herring iAlosa sp., 1%), 

 hermit crab (Pagurus longicarpus , 1%), andisopod 

 (Olencira praegustator, 19c). On a volume basis 

 weakfish were first, sand shrimp second, and the 

 rest remained in the same order. Fish under 45 cm 

 fed predominantly on invertebrates, while larger 

 ones ate more fish. Poole ( 1964) found sand shrimp 

 the primary organism eaten by summer flounder 

 in Great South Bay, and that out of 10 fish species 

 eaten, the winter flounder, Pseudopleuronectes 

 americanus, was first by weight and the weakfish 

 next to last. These observations indicate that the 

 diet of summer flounder reflects local abundances 

 of prey species. 



Flounder caught during the day had a greater 

 volume of food in their stomachs (x =5.1 ml) than 

 those caught at night (x =3.3 ml), but the differ- 

 ence was not significant according to £-tests. 



RACIAL ANALYSIS 



The following morphometric and meristic 

 characters were measured or counted on fish 

 caught in 1966: total, standard, head, and upper 

 jaw lengths; dorsal, anal, and pectoral fin rays; gill 

 rakers on the first arch; and vertebrae (Table 5). 

 All measurements and counts were made on the 

 left side for uniformity. The number of caudal fin 

 rays (17) and pyloric caeca (4) was constant so 

 counting of these characters stopped after 20 fish. 

 Woolcott et al. (1968) reported 18 caudal fin rays, 

 with the posteriormost dorsal ray being very small 

 and easily overlooked in unstained specimens. We 

 missed this 18th ray in our count. 



Ranges of some meristic and morphometric 

 characters examined exceed those reported in the 

 literature (Table 5). Analysis of variance showed 

 no significant difference in the counts of the six 

 variable meristic characters due to age or sex. 



Comparison by £-test of meristic character 

 counts on summer flounder sampled in Delaware 

 Bay, Chesapeake Bay, and North Carolina (Table 

 6) gave inconclusive results. There was no sig- 

 nificant difference between these areas for num- 

 bers of dorsal fin rays and vertebrae. Differences 

 based on gill raker counts by Woolcott et al. ( 1968) 

 might not be valid, because Deubler (1958) stated 



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