Table 22 1 — Shad eggs and the spawning condition of gizzard the site j d() t b y fch avo id e d the gear, 



s/ma collected during various periods of the day on a spawn- J «"«* »"" &^»* » 



ing srte near Put-in-Ray, Ohio, in June 1954 and 1955 because the nets were treated with a copper 



preservative that rendered them greenish and, 



hence, less visible than untreated nets, and were 



set in aquatic vegetation which almost wholly 



obscured them. White bass, smallmouth bass, 



and rock bass, but very few gizzard shad, were 



caught in the day. 



During the midnight lifts, however, when the 



moon shone brightly, I saw many fish swirling 



and breaking water. The moonlight was not 



bright enough for me to judge accurately the 



species or size. The gill nets caught many gizzard 



shad, however, during those nights and had many 



shad eggs adhering to the webbing. The only other 



spawning gizzard shad indicates possible periods fish caught at those times were a few carp. 



i No observations in 1955. 



of rest between spawnings. 



The males captured on the spawning site during 

 the period of most active spawning outnumbered 

 the females three to one. This abundance of 

 males may be attributed to one or more of the 

 following: Their actual daily recruitment to the 

 spawning site, their probable greater activity, 

 or their possible longer stay on the site. I was 

 unable to distinguish any degrees of "spentness" 

 in the male. 



Not having observed details of behavior of 

 spawning gizzard shad, I can offer only the 

 statements of others on spawning behavior. 

 Langlois (1954) observed gizzard shad spawning 

 on May 29, 1935, in North Reservoir at Akron, 

 Ohio, near shore in 6 to 12 inches of water at a 

 water temperature of 67° F. During oviposition, 

 a female was flanked by a male on each side. 

 No time of day was indicated. M. B. Trautman 

 (personal communication) observed about 20 

 shad spawning in Buckeye Lake, Ohio, at 73° F. 

 on May 23, 1939. The females, pursued by 

 several males, swam rapidly toward a sloping 

 stone wall, turned abruptly, and deposited their 

 eggs. A. G. McQuate (personal communication) 

 observed shad spawning in Sandusky Bay, Ohio, 

 on May 24, 1954 (temperature 62.5° F.), along a 

 stony shore near 12 m. (noon) in the shade of an 

 overhanging tree. Female shad were pursued by 

 several males. The fish frequently broke water. 



My own failure to see gizzard shad spawning 

 during the daytime at the spawning site in Fishery 

 Bay can be attributed to their failure to spawn at 

 that time. The small daytime catches in gill 

 nets suggest that shad were extremely scarce at 



GIZZARD SHAD IN WESTERN LAKE ERIE 

 774-711 O— 66 9 



Hatching and Early Development 



The eggs of the gizzard shad are heavier than 

 water and slowly sink after they are spawned. 

 The egg capsules adhere to surfaces that they 

 contact, such as submerged aquatic plants and 

 stones. Experiments in the Ohio State Hatchery 

 at Put-in-Bay indicated that the hatching time 

 varies from about 36 hours to about a week, 

 depending on the temperature. This finding 

 agrees with Warner's 2 observations at Buckeye 

 Lake, Ohio. 



In a series of experimental hatchings over 2 

 seasons, I failed to keep the young alive beyond 

 the 10th day after hatching. Mortality was low 

 up to the 9th day and the fish appeared to be 

 doing well; then suddenly on the 10th day only 

 a few remained alive out of thousands. The 

 remainder died before the day ended. Results 

 were the same in running and aerated water and 

 with various kinds of food, such as natural food 

 from the lake and cultured protozoans. 



The movements of the newly hatched gizzard 

 shad were an upward swimming and a downward 

 settling — in each direction the head was foremost. 

 This behavior continued 3-4 days. The whole 

 body moved sinuously with such rapidity that the 

 individual movements could not be followed. At 

 this time the pectoral fins were not yet used to 

 any extent. On the fourth day the fry began to 

 swim horizontally as well as upward and down- 

 ward. Their mode of swimming at this age, 



2 Warner, E. N. 1940. Studies on the embryology and early life history 

 of the gizzard shad, Dorosoma cepedianum LeSueur. Doctoral thesis, Ohio 

 State University. (Unpublished.) 



417 



