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Food, Age and Growth of the Tessellated Darter, Etheostoma olmstedi, in Massachusetts
| Content Provider | Semantic Scholar |
|---|---|
| Author | Layzer, James B. Reed, Roger J. |
| Copyright Year | 1978 |
| Abstract | Tessellated darters (Etheostoma olmstedi) fed primarily on tendipedid larvae in the Connecticut and Mill rivers from June to September, but by October shifted to a diet of Trichoptera larvae in the Mill River. Feeding in the Mill River on 8-9 July 1970 occurred throughout daylight hours but was heaviest between 0600 and 1200. Back-calculated lengths varied within age groups and the length ranges overlapped between age groups in the five darter populations studied. In the Mill River, young darters appeared to remain near a spawning area until they reached about 30 mm TL. Introduction The tessellated darter (Etheostoma olmstedi) occurs throughout eastern United States from southern New Hampshire to northern Florida, frequenting a variety of habitats but preferring quiet stream pools with sand or mud substrates (Cole, 1967). In some areas, it is an important forage species for smallmouth bass (Micropterus dolomieui), walleye (Stizostedion v. vitreum) and American eel (Anguilla rostrata) (Raney and Lachner, 1942, 1943; Ogden, 1970). Although various aspects of the tessellated darter's life history have been documented by Adams and Hankinson (1928), Atz (1940), Raney and Lachner (1943) and Tsai (1972), no detailed study of its feeding habits has been made. The present paper describes seasonal food, daily feeding periodicity, age and growth of the tessellated darter in Massachusetts. Materials and Methods We used an electric shocker, seines and rotenone to sample darters from five areas in Massachusetts: Mill River, Amherst; Connecticut River, Hatfield; Holyoke Canal, Holyoke (20 October 1970) ; West Branch of the Swift River, New Salem (17 July 1967) ; and Wading River, Mansfield (24 July 1970). (Specimens were preserved in 10% formalin immediately after collection. Later, total length was recorded to the nearest millimeter and weight to the nearest 0.01 g; and sex was determined. To determine seasonal food habits, darters were collected in the Connecticut River biweekly from the 1st week in June through September 1970; and in the Mill River through October 1970. On 8 and 9 July 1970, we made four collections at* 6-hr intervals to determine darter feeding periodicity in the Mill River. Stomach contents were examined with a dissecting microscope at 15-45X. Since preliminary examination of stomach contents indicated that darters fed almost exclusively on tendipedids from June to August, we estimated visually the volumes of food items. Scales were removed from an area below the lateral line at the posterior tip of the pectoral fin (when extended posteriorly along the body), dry-mounted between two glass slides, and examined with a Bausch and Lomb tri-simplex projector (50X). Computer programs developed by Mawson and Reed ( 1970) were used for most age and growth calculations on a 3600 CDC computer at the University of Massachusetts. Results and Discussion Food.?Tessellated darters in the Mill and Connecticut rivers fed primarily onr-tendipedid larvae throughout the summer (Fig. 1). Other dipterans made up less than 5% of the total food volume. Incidental food items in the two streams were annelids, cladocerans, fish eggs and Ephemeroptera nymphs ("D" in Fig. 1). In the Mill River tendipedids reached peak importance in July, when they contributed nearly 98% to the total food volume. Trichoptera larvae became important in August and dominated the diet in October. In the Connecticut River, tendipedid larvae were also by far the most important food from June to September. Levesque (1970) reported that the abundance of midge larvae in the Connecticut River benthos was cyclical in 1969, and these fluctuations were reflected directly in the food of juvenile American shad (Aiosa sapidissima). However, we did not observe cyclical fluctuations in the diet of darters in the present study. 1 Contribution No. 48 of the Massachusetts Cooperative Fishery Research Unit jointly supported by the U.S. Fish and Wildlife Service, The Massachusetts Division of Fisheries and Wildlife, the Massachusetts Division of Marine Fisheries and the University of Massachusetts. 460 The American Midland Naturalist 100(2) Darters collected from the Mill River on 8 and 9 July fed throughout the day but principally between 0600 and 1200 hr (Table 1). The percentage of undigested food in the stomachs was smallest at 2400 hr; at this time most of the stomach contents were in a late stage of digestion and only the sclerotized head capsules of tendipedid larvae were identifiable. The |
| Starting Page | 459 |
| Ending Page | 459 |
| Page Count | 1 |
| File Format | PDF HTM / HTML |
| Volume Number | 100 |
| Alternate Webpage(s) | http://forum.nanfa.org/index.php?app=core&attach_id=12025&module=attach§ion=attach |
| Alternate Webpage(s) | https://doi.org/10.2307/2424847 |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
