FISHERY BULLETIN: VOL. 72, NO. 2 



The food habits of E. crossotus are distinct 

 from those of the other three species (Table 1). 

 Pseudodiaptomus coronatus dominated the stom- 

 ach contents of E. crossotus but accounted for 

 only an insignificant fraction of the stomach 

 contents of A. quadrocellata , C. spilopterus, and 

 S. aquosus. The stomach contents of each of the 

 latter three species were dominated by Neomysis 

 americana. 



Of secondary importance in the stomachs of 

 E. crossotus were polychaete annelids, especially 

 the spionid, Paraprionospio pinnata. The im- 

 portance of Pa. pinnata is extended if the assump- 

 tion is made that most of the animals listed under 

 Spionidae (Table 1) were, in fact. Pa. pinnata 

 in a state of decomposition, making specific 

 identification impossible. 



No fish remains were found in any of the 

 stomachs ofE. crossotus examined, although they 

 were found in A. quadrocellata, C. spilopterus, 

 andS. aquosus. The difference in primary feeding 

 habits between E. crossotus and the other three 

 species of bothids appears to be a reflection of 



relative mouth size (Figure 2). E. crossotus has 

 a very small mouth relative to head length (mouth 

 averages about 6 into head), whereas, A. quadro- 

 cellata, C. spilopterus, and S. aquosus all have 

 relatively larger mouths in proportion to head 

 length (mouth averages 3 to 4 into head). The 

 small mouth of E. crossotus correlates with its 

 selectivity for small organisms (such as Ps. 

 coronatus, which range {vom 1 to 1.5 mm in length) 

 and those of small diameter (such asPa. pinnata). 

 While the remaining three fish species appear to 

 favor A^. americana as a primary food organism, 

 the diversity of sizes or organisms available to 

 them appears greater. A'^. americana ranged from 

 6 to 12 mm in length in our collections. This 

 organism was not completely excluded from the 

 food of £■. crossotus (Figure 3) but was fed upon 

 only to a limited extent. 



Table 1 presents the food habit data collected 

 for each species without regard to season of the 

 year, location in the estuary, or size of the fish 

 under investigation. In order to more critically 

 evaluate the data collected on each species, a 



Cithorichthys spilopterus 



Ancylopsetta quadrocellata 



Scophthalmus aquosus 



Etropus crossotus 



I cm 



Figure 2. — Line drawings of the four species of Bothidae discussed depicting the differences in mouth size relative to body length. 



518 



