LA ROCHE: TROPHIC PATTERNS AMONG LARVAE OF SCULP1NS (COTTIDAE) 



Table 11.— Comparison of the major prey of similar-si zed cot- 

 tid larvae from January and February 1973. Food items are 

 listed in order of decreasing rank by the value (in parentheses) 

 of the product. % frequency of occurrence X % of total number; 

 only items with a value MOO are presented. Food item abbre- 

 viations are: BN = Balanus nauplii; Cose = Coscinodiscus sp.; 

 E(«ij = Invertebrate eggs (single); Mn = Microsetella norvegica; 

 Ps = PseudocalanvLS minutus; Tem = Temora longicorntis; Ts = 

 TYs&espp.; UCalc = Unidentified calanoidcopepodites; UHaor 

 n = Unidentified harpacticoid adults or nauplii. 



Myoxocephalus aenaeus 



Size range (mm) 6.5-7.4 



Ranked food items Mn (8.500) 

 Cose (450) 



Myoxocephalus octodecemspinosus 



Size range (mm) 7.2-8.4 8 5-9.4 



Ranked food items Mn (8,900) 



Myoxocephalus scorpius 



Size range (mm) 7.5-8.4 



Ranked food items Cose (7,043) 

 Mn (305) 



Tnglops murrayi 

 Size range (mm) 

 Ranked food items 



Mn (5,420) 

 Tem (2,330) 

 E,s„ (478) 



8.5-9.4 

 Cose (4,445) 

 Eon (956) 

 UHn (139) 

 Mn (106) 



8.5-8.9 

 Ps (4,500) 

 UCalc (3,200) 

 Tem (200) 

 Ts (100) 



9.5-10.4 



Cose (2.240) 

 UHn (1,029) 

 UHa (1,000) 

 E„i, (849) 

 BN (300) 

 Tem (200) 



9.0-10.4 

 Ps (5,700) 

 UCalc (3.700) 



plete overlap(Fig. 2). Except for the consistently 

 high degree of overlap between the diets of 

 Myoxocephalus aenaeus and M. octodecemspi- 

 nosus, overlap among cottid larvae in general 



Species 



M aenaeus 



M. octodecemspinosus 



M. scorpius 



T. murrayi 



o» 



Q. 



Winter 



Figure 2.— Matrix of Schoener (1970) index values measuring 

 percent diet overlap among species pairs of cottid larvae from 

 winter (January-February) and early spring (March) collec- 

 tions in the Damariscotta River estuary, Maine. 



Table 12.— Comparison of the major prey of similar-sized cottid larvae from March 1973 {Myoxocephalus spp. and T. murrayi) 

 and January-April 1972-74 (H. americanus). Food items are listed in order of decreasing rank by the value (in parentheses) 

 of the product, % frequency of occurrence X % of total number; only items with a value MOO are presented. Food item abbrevia- 

 tions are: BN = Balanus nauplii; DZ = decapod zoea; E (S1) = Invertebrate eggs (single); FL = fish larvae; H = Harpacticus spp.; 

 Mn = Microsetella norvegica; Ps = Pseudocalanus minutus; Tem = Temora longicornis; Ts = Tisbe spp.; Tur = Turbellaria; 

 UCala or c = Unidentified calanoid adults or copepodites; UCyc = Unidentified cyclopoids. (* = tied rank.) 



835 



