FISHERY BULLETIN: VOL. 80, NO. 4 



Table 2. — Summary of food habits of 18 Myoxocephalus aenaeiis larvae 

 captured on 22 January and 6 February 1973. %FO = percent frequency 

 of occurrence (FO) among larvae containing food; %N = percent of the total 

 number (TV) of food items ingested by larvae in that size group. 



Table 3.— Summary of the food habits of 129 Myoxocephalus aenaeus larvae captured on 5, 6, 19, and 20 March 1973. %FO = 

 percent frequency of occurrence (FO) among larvae containing food; %JV = percent of the total number (.V) of food items ingested 

 by larvae in that size group. 



in January-February and not in March when 

 barnacle nauplii were the principal prey of lar- 

 vae, because it is likely that some proportion of 

 these diatom cells were released from the guts of 

 Balanus nauplii during digestion. Cells ^25 yum 

 in diameter were found inside undigested Ba- 

 lanus nauplii taken from the guts of cottid lar- 

 vae. Flatworms (Turbellaria) ingest diatoms 

 whole (Jennings 1957) and these may also have 

 contributed Coscinodiscus cells. Most of the 

 calanoid and harpacticoid copepods ingested by 

 cottid larvae were adults and, for Temora longi- 

 comis, mostly females. Bundles of setae of un- 

 determined origin seemed to accumulate in the 

 guts of cottid larvae. The most likely sources of 



these are the appendages of Microsetella and 

 Balanus nauplii. 



Diet Comparisons 



Relative importance of each prey taxon was 

 estimated from the product of %FO and %N. Ma- 

 jor prey (%FO X %N>100) of only similar-sized 

 larvae were ranked according to this value and 

 compared for seasonal as well as inter- and intra- 

 specific differences (Tables 11, 12). In general, 

 the same trophic patterns were present among 

 larvae in size groups not included in these com- 

 parisons (Tables 2-10). 



In January and February the dominant prey of 



830 



