. Bulletin. Natural history; Natural history. September 1985 125 Years of Biological Research 277 Fig. 2. - EggsofSriz- ostedion vitreuin on spawning ground at Lake Gogebic, Michigan, 12 May 1948. From Esch- meyer (1950). (Photo pro- vided by the Institute for Fisheries Research, Fisheries Division, Mich- igan Department of Nat- ural Resources.). ized, nesting broadcaster may be mon- ogamous (Deedler & Willemsen 1964). Broadcasters Group A. Spawn over open substrate Stizostedion vitreum (Eschmeyer 1950) S. canadense (Nelson 1968) S marinum (Berg 1949) Percarina demidoffi (Berg 1949) Gi'oup
. Bulletin. Natural history; Natural history. September 1985 125 Years of Biological Research 277 Fig. 2. - EggsofSriz- ostedion vitreuin on spawning ground at Lake Gogebic, Michigan, 12 May 1948. From Esch- meyer (1950). (Photo pro- vided by the Institute for Fisheries Research, Fisheries Division, Mich- igan Department of Nat- ural Resources.). ized, nesting broadcaster may be mon- ogamous (Deedler & Willemsen 1964). Broadcasters Group A. Spawn over open substrate Stizostedion vitreum (Eschmeyer 1950) S. canadense (Nelson 1968) S marinum (Berg 1949) Percarina demidoffi (Berg 1949) Gi'oup B. Spawn over male-constructed pit S. lucioperca (Kryzhanovshy et al. 1953) Stranciing Stranders have the unique habit of encasing their eggs in long gelatinous strands. A ripe female is followed by several males through beds of vegeta- tion (sometimes tree roots or debris) in slowly flowing or standing water. The males release sperm as she extrudes a convoluted egg strand (Worth 1892; Ti-easurer 1981). The strand is gelatin- ous, transparent, hollow, and arranged in bellowslike transverse folds. When first laid, the shape of the egg mass is similar to that of the ovarian cavity (Fig. 3), but eventually it stretches (Fig. 4) and may reach a length of m and a width of 10 cm (Hardy 1978). Egg stranding is known to occur in Perca /Zai;esce«s(Mitchill) (Worth 1892; Har- rington 1947; Hergenrader 1969) and P fluviatilus Linnaeus (Seeley 1886:27; Wheeler 1969:322; Treasurer 1981). It also may occur in Gymnocephalus cer- nua (Linnaeus), as described by Seeley (1886:36) and Wheeler (1969:321), al- though some authors (, Nikol'skii 1961:369; Muss 1978:161) discuss spawning in Gymnocephalus without mentioning egg strands. Stranders Gymnocephalus cernua (Seeley 1886) Perca flavescens (Worth 1892) P fluviatilus (Seeley 1886) Stranding is probably a direct deriv- ative of broadcasting. The eggs become encased in gelatin in the ovaries and when emitted remain part of a cohesive mas
Size: 1827px × 1368px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., booka, bookcentury1900, bookdecade1910, booksubjectnaturalhistory
