I ; v s VIC'InK K. sHKi.i (iKH. 



state, as well as practicable, tin- succession in these ponds with 

 particular reference to fish. 



I. Statement of I : .colo':icdl Succession.- A Mateim-nt of sin 

 sion can In- best made in the form of a hi-tory of Pond 14 (Fig. i , 

 From our knowing- of" ilu- origin of tin- pond- and ihcir present 

 topography, it is reasonably certain th.i! ill. n- was < lime when 

 I'oiid 14 was nio'-f clost !\- associated with the lake than Pond i 

 'in Fk. i. hypothetical stai;e B). Ai such a time 

 I'oiid 14 contained le-s vegetation than we now find in Pond I. 

 For a kno\\lrd-e of the ecological character of tin- fish which 

 inhabit such pond-, \\ i have collected from a pond of tin same 

 origin as tho-M- made' tin subject of tin- present study. This 

 one has mainiaiiied a close connection with Lake Michigan and 



eives the waves of the lake during the spriiiL' and winter 

 -tornis. ll flows into the- lake during every hi-hu ater period. 

 This pond is at Beach Sta.tion, four miles north of \Yaukcgan. 111. 

 Nf( ar its outer end it presents a clear bottom of sand and gravel, 

 little vegetation and no humus. In this outer portion we have 

 collected the pike (Esox Inciiix'i, which prefers clear, clean, cool 

 water (Forbes and Kichardson, '08) ; the red horse ( Moxostoma 

 (iitri'oliihi), which dies quickly in the aquarium if the \\ater i-- the 

 least impure and Miccumbs to impure conditions in its natixe 

 wai. - ! orbes and Richardson, '08); Xntrnpix cdyit^i, coninu n 

 in < "a\ -u^a Lake and the lower course- of its tributaries i Keed and 

 \\ii-ht, '09). As compared with Illinois waters, the-.- streams 

 \\ould be counted clear. \Yealso found Xolrnpis cornntus, which 

 shows a marked preference fcr clear waters (Forbes and Kichanl- 



-oll, 'O? 



\Yhcn Pond 14 was in a very earl) stage (hypothetical stagi B, 



Fig. I) it must ha\'e been occupied b\ fishe- which \\eri eco- 

 logically similar to the red hors,-, the pike, the < tyuga minnou, 

 and the common shiner. This i- a comimmit\ of species which 

 may be characteri/ed as requiring clear, ck-an waters, clean 

 bare bottom (especially during ilu- breeding season), and littk- 

 vegetation. Such fishes may be designated as pioneer ecological 

 types. To this group might be added such fishes as the common 

 perch, which is hardy and lives in a \\id< rang< ol conditio 

 Following the history of Pond 1.1 furiln r, \\ i note thai as the 



