FISHERY BULLETIN: VOL. 75, NO. 4 



TABLE 4. — Growth of croaker, Micropogonias undulatus, from different estuarine areas along U.S. Atlantic and Gulf of Mexico coasts. 



'Gear: PI, plankton net; S. seine; T. trawl. 



2 Age-group: represents smallest group of young-of-the-year first taken from 

 age-group I. Parentheses indicate that the boundary of age-groups and I is 



January on, other fishes (including overwintering young-of-the-year) are included in 

 indistinguishable. N.S.; no sample. 



Carolina), and in October in Texas. Arnoldi et al. 

 (1973) "tagged" young-of-the-year croakers (9-48 

 mm TL). Their successful recaptures indicated 

 that individual croaker remained in the particular 

 marsh for only 1 to 4 mo, which was much shorter 

 than the total length of time croaker were ob- 

 served in the marsh (October- June). Thus, they 

 also suggested that several croaker "populations" 

 may utilize coastal marsh as nursery ground dur- 

 ing the course of the year. White and Chittenden 

 (1977) indicated that some croakers in the Gulf of 

 Mexico may lack the first (overwinter) ring on the 

 scales. This suggests that some croakers may 

 spawn in the spring in the Gulf of Mexico. 



Massmann and Pacheco (1960) reported the dis- 

 appearance of young croakers from the York 

 River, but their conclusion may have been in error 

 because of selectivity of their fishing gear. Haven's 

 ( 1957) length frequencies for croakers during 1952 

 and 1953 differ from those presented by 

 Massmann and Pacheco (1960) for the same years. 

 No fish <100 mm TL were reported by Massmann 

 and Pacheco ( 1960), but their gear was a net with 



%-in (about 1.9-cm) mesh, whereas Haven (1957) 

 used V4-in (about 0.6-cm) mesh. Joseph (1972) at- 

 tributed the decline of croaker in the commercial 

 catches of the middle Atlantic coast to climatic 

 trends. Present data support his hypothesis. The 

 apparent increase in juvenile croakers in 1973 and 

 1974 was probably due to warmer winter months. 

 Mean bottom temperatures of the York River 

 channel were about 3.6°C and 3.2°C in January 

 and February, respectively, from 1967 to 1971 

 (Markle 1976). It was 6.7°C for January and 6.3°C 

 for February in 1973 and 1974 ( Figure 2). The year 

 class strength of croaker in the York River was 

 dependent on the success of the late young-of-the- 

 year group (Figure 16, mode I), which stayed in the 

 estuary through the winter. Historical York River 

 trawl data show mass mortalities of young-of- 

 the-year croaker during some cold winters (VIMS, 

 Ichthyology Department, unpubl. data). 



Feeding Mechanisms 



The Sciaenidae have the widest spectrum of 



678 



