36 U. S. BUREAU OF FISHERIES. 



BLUE-SPOTTED SUNFISHES (Enneacanthus gloriosus and E. obesus). 



The two species of Enneacanthus {gloriosus and ohesus) which 

 together are distributed throughout the Atlantic coastal watershed 

 from Massachusetts to Florida are so closely similar specifically and 

 in habits that the author is not sure that they were always distin- 

 guished in his limited field observations which were made chiefly in 

 Palisades Interstate Park and near Bristol, Pa. However, most of 

 them Avere certainly Enneacanthus gloriosus. 



Of all the sunfishes found in this region the small size and vege- 

 tation-haunting habits of these species would seem to recommend 

 them most highl}' as mosquito destroyers. Seal (1908, ]). 352) con- 

 siders them one of the most valuable fishes for this purpose, and the 

 author's observations lend support to his view. 



Table 5 (p. 37) records the contents of stomachs of 36 specimens 

 taken in Car Pond and Cedar Lake, N. Y,, during July and August, 

 1919. It is noteworthy that the food was almost exclusively insects 

 and crustaceans. There were no mollusks and no worms and mere 

 traces in a few cases of algse and other plant remains. Larvae of 

 (Julex pipiens and Aedes sylvestris (in two cases in large numbers) 

 were found in 10 stomachs, a pupa of Culex pipiens in each of 2, and 

 eggs or egg boats in 4, the whole comprising about 6 per cent of the 

 entire stomach contents. Chironomid larvse, together with a few syr- 

 phids and other Diptera, constituted about 23 per cent, all other in- 

 sects 35 per cent, crustaceans, chiefly minute forms, 30 per cent, leav- 

 ing 6 per cent for water mites, spiders, algse and other plants, and 

 miscellaneous objects. In one case the entire contents consisted of 

 amphipods; in another 70 per cent was Cyclops. 



Examples of Enneacanthus gloriosus taken in a sluggish, weed}' 

 creek near Bristol, Pa., were used chiefly in laboratory feeding ex- 

 periments in which it was determined that when confined in aquarium 

 tanks they fed freely upon Culex larvae and egg boats which were 

 often detected even among masses of floating Elodea, Ceratophyllum, 

 Lemna, and other water plants. 



A number of observations and field experiments were made at 

 Palisades Interstate Park. In shallow plant-OTOwn waters in Car 

 Pond a few blue-spotted sunfishes (Table 5, No. 2356a) — some of 

 which may have been Enneacanthus ohesus — were taken along with 

 common simfishes. None of these was found to contain mosquito 

 remains. Indeed, their stomachs contained \&ry little food of any 

 kind, and it may be that owing to the presence of great numbers of 

 the more aggressive and pugnacious common sunfish they were pre- 

 vented from feeding freely. 



The most favorable conditions for studying this species were 

 found in Cedar Lake, particidarly at one point (M), to which at- 

 tention was directed by Prof. Hankinson. This was an area of shal- 

 low water (fig. 9) sheltered behind an island and thickly grown 

 with aquatic vegetation, chiefly Myriophyllum and Utricularia, to- 

 gether with patclies of Sagittaria and floAvering rush. The shore 

 here Avas swampy Avith a flooded area about 20 by 30 feet cut off from 

 the lake partly by projecting banks and partly by masses of A^egetation 

 and brush (fig. 10). There Avas also a number of pools of A^arious 

 sizes isolated by rocks. In the lake itself ,at this point Enneacanthus 

 gloriosus was found to be by far the most abundant fish, though the 



