| Abstract: | We describe hatching and the morphological and meristic characteristics of 2.5-5.6 mm long ruffe protolarvae (Gymnocephalus cernuus). Eggs and sperm from St. Louis River ruffe were mixed, producing fertilized eggs that were 0.9-1.2 mm in diameter. Newly hatched protolarvae were 2.5-3.2 mm long. They had 14-15 preanal and 23-24 postanal myomeres, a continuous finfold of even width, unpigmented eyes, and a large anterior oil globule in the yolk sac, and the head deflected over the yolk sac. Pectoral fin buds appeared on the dorsal side of the yolk sac 5 hours after hatching. Two-day-old protolarvae had fully pigmented eyes, and the head was free from the yolk sac. Three-day-old protolarvae were 3.9-4.3 mm long and possessed opercula, gills, pectoral fins, and a functional jaw. Feeding and swimming began about one week after hatching when the yolk sac was almost completely absorbed. Protolarvae grew rapidly at 20-22 degrees C and were 4.9-5.6 mm long after 13 days. Newly hatched ruffe protolarvae are distinguished from other Lake Superior percids by having the fewest preanal myomeres (14-15), the head deflected over the yolk sac, continuous finfold of even width, and a total length of less than 4.0 mm. |
| Genre: | Article |
| ProdID: | 1000742 |
| Citation Author: | French, John R. P., III; Edsall, Thomas A. |
| Citation Contributing Office: | Great Lakes Science Center |
| Citation Datum: | |
| Citation Day: | |
| Citation Edition: | |
| Citation Editor: | |
| Citation End Page: | 68 |
| Citation Issue: | 1 |
| Citation Keywords: | |
| Citation Language: | English |
| Citation Larger Work Title: | Journal of Freshwater Ecology |
| Citation LatN: | |
| Citation LatS: | |
| Citation LonE: | |
| Citation LonW: | |
| Citation Month: | |
| Citation No Pagination: | |
| Citation Number Of Pages: | 9 |
| Citation Online Only Flag: | |
| Citation Phsyical Description: | p. 59-68 |
| Citation Projection: | |
| Citation Public Comments: | |
| Citation Publisher: | |
| Citation Series: | |
| Citation Series Code: | |
| Citation Series Number: | |
| Citation Search Results Text: | Morphology of ruffe (Gymnocephalus cernuus) protolarvae from the St. Louis River, Lake Superior; 1992; Article; Journal; Journal of Freshwater Ecology; French, John R. P., III; Edsall, Thomas A. |
| Citation Start Page: | 59 |
| Citation Volume: | 7 |
| Citation Year: | 1992 |
| Type: | citation/reference |
| Text: | Morphology of ruffe (Gymnocephalus cernuus) protolarvae from the St. Louis River, Lake Superior; 1992; Article; Journal; Journal of Freshwater Ecology; French, John R. P., III; Edsall, Thomas A. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Wed, 1 Jan 1992 00:00 -0600 |
| Publisher: | |
