Rough Fish Research Articles

The Increase in Game-Fish Populations in East Okoboji Lake, Iowa, following Intensive Removal of Rough Fish

Test seining in East Okoboji Lake, Dickinson County, Iowa, in 1940 revealed a large population of rough fish and relatively few game fish. The Iowa Conservation Commission therefore intensified its rough-fish removal activities on the lake. Following several years of this expanded program, significant increases of game fish occurred. These increases are reported in the form of comparative data on catch per unit effort over a period of 12 years, from 1940 to 1951. General observations indicated an improved environment for game fish and an increase in angling success.

The Use of Rotenone to Remove Rough Fish for the Purpose of Improving Migratory Waterfowl Refuge Areas

Along the shores of Sandusky Bay in Ohio some shallow lakes and marshlands were developed into excellent refuge areas for migratory waterfowl. In Middle Harbor, a marsh which had provided a resting place for thousands of wild ducks during the fall, a large population of carp developed. The value as a waterfowl refuge decreased steadily as the population of carp increased. Therefore, it seemed that if the carp could be removed that the aquatic vegetation which originally existed in the marsh would again flourish, and the food for wild ducks would again become abundant. This theory was tested in a small way in a small marsh covering about one half acre, using rotenone in a manner somewhat like that described by Siegler and Pillsbury (J. Wildl. Mgt., 10: 308-316, 1946). Within two weeks an excellent bloom of algae had developed and the water became clear. Since the area of Middle Harbor was 250 acres, the problem of application was difficult. A helicopter was used to apply the rotenone on October 6, 1948 and proved to be ideal for this purpose. This is believed to be the first use of a helicopter to apply rotenone emulsion for fish control. METHOD OF APPLICATION

Fish-Population and Catch Data from Minnesota Lakes

From seining it is concluded that the average game-fish lake of southern Minnesota has a fish population of about 110 pounds per acre of which about one-sixth is made up of large predaceous species. Pike (Esox lucius) is the most widespread and, from the viewpoint of fishery management, the most valuable predatory fish in Minnesota waters. Pike is nearly always a co-dominant with largemouth black bass (Micropterus salmoides) in “bass-panfish” lakes and with yellow pikeperch (Stizostedion v. vitreum) in “walleye” lakes. As a check on populations of yellow perch (Perca flavescens) and small centrarchids, pike are probably more effective than either bass or pikeperch. A comparison of the poundage composition of the anglersˈ take with the poundage composition of the fish population found by seining shows that fishing pressure in Minnesota is much heavier for the large predaceous species than for the panfishes. Pikeperch are subjected to heaviest fishing pressure, with pike second. Rough-fish lakes in southern Minnesota were found by test seining to have an average of about 375 pounds of fish per acre, of which 280 pounds were rough fish, largely carp (Cyprinus carpio). An average removal of 97 pounds per acre per season over 25 years has had no permanent effect in reducing the size of carp and buffalo populations in 14 such waters. In general, rough fish appear to have little effect on the total poundage of game fish in southern Minnesota lakes. Rough fish are, however, usually associated with large populations of crappies (Pomoxis spp.) and somewhat reduced perch and pike populations. Gill-net and hoop-net catches and indices are considered. Fishing selectivity of gill nets and the use of poundage data from gill-net catches in judging the relationship between perch and predatory fish are discussed.

Fish Production in Lakes as a Guide for Estimating Production in Proposed Reservoirs

A LARGE number of artificial reservoirs are being proposed for early construction throughout the United States, which in many cases will have a profound effect on fish and wildlife. It has become imperative, therefore, to attempt to evaluate this effect prior to the completion of construction plans, in order to obtain such modifications in design or water utilization as will assure the maximum benefits to fish and wildlife compatible with other uses and values. This paper touches on only one phase of this evaluation-the quantities of fish that the proposed reservoirs may be expected to produce. Opinions on this subject vary from extreme pessimism to rosy optimism, depending largely on the observers' experience. Admittedly, there is a tremendous difference in the potential yield of various bodies of water, from the 200pounds (or better) per-acre yield of the fertilized, properly-stocked farm pond to the one-pound-per-acre yield of Lake Superior. Yet it is possible to create a useful yardstick by studying observed production data. Such a measure of yield, based on actual experience, is bound to give a more reliable estimate than pure guesswork. There are two types of data available on the populations of fish in lakes and ponds: total populations and annual yields. Unfortunately, both types of data are rarely available for the same body of water. Total population data are available only for small lakes and ponds, chiefly ones in which the fish have been poisoned. Generally speaking, only those ponds have been poisoned whose populations were abnormal in some respect. Either the natural balance between the larger predators and the smaller fish had been upset in such a manner that the lake was crowded with stunted panfish, or the lake had become heavily populated with carp, buffalo, or other rough fish, to the detriment of more desirable species. Obviously, the data from these atypical lakes are not truly representative of the average lake; but being the only data available they are presented for what they are worth. Statistics on the arinual yield of lakes are better than those on total populations because they usually refer to lakes with more or less normal populations. All the available literature on lake production has been examined, and the pertinent data compiled as shown in Table I. However, it was necessary to omit, for various reasons, certain ponds and lakes from consideration. For instance, the annual yield for Standard Lake (16.0 acres) given by Beckman (1941) referred to fish stocked immediately after the poisoning of the entire population, and thus does not represent the yield from a normally balanced population. Cahn (1939) gives the weight of carp taken from Neosha Mill Pond in southern Wisconsin, but not the area of the pond. A preliminary creel census of the trout catch in Fish Lake, Utah, given by Hazzard (1935) is omitted since the study covered but 13 days. Total yields from certain

Alternative Methods in Upland Gamebird Food Analysis

noxious plant species is another problem that cannot be ignored, especially in southern waters where some such pests are common-lotus is an example. Constant-level pools with heavy growths of aquatic plants, especially emergent species, afford excellent breeding places for malaria mosquitoes. For this reason, such ponds should be at least one mile from human dwellings occupied at night; otherwise the water levels should be managed on a schedule favorable for malaria control. The 68-acre pond mentioned above could also be used as a constant-level pool, but will be more useful as a dewatering project, because of both the malaria control aspect and the presence of rough fish in the inlet.

The Possibilities of a Commercial Fishery in the TVA Impoundments and its Value in Solving the Sport and Rough Fish Problems

Increased prices and the scarcity of meat have created a much greater demand for fishery products. Meeting this demand will require the fullest utilization of our fresh-water fishery resources because our marine fishery is partly inoperative due to war conditions. It is believed that the fishes produced in the TVA impoundments can make a significant contribution to the food-for-victory program. Investigations conducted on these impoundments during the past 5 years indicate that they are rich in fish life and are capable of supporting an extensive fishery. Although all forms of netting are prohibited, there was an average take of 25 pounds of fish per acre by sport and setline fishermen during 1940 in the four lower reservoirs: Guntersville, Wheeler, Wilson, and Pickwick. This rate of production greatly exceeds the average yield of 1.8 pounds per acre from the Great Lakes. Fish population studies in the backwaters of Wheeler Reservoir suggest that much larger catches could be made if certain types of gear, such as seines, trap nets, and gill nets, were legalized. These studies revealed populations as high as pounds per acre in waters only 2 to 3 feet deep. The average population per acre for all areas studied was 8,246 fish weighing 576 pounds. Coarse fish were dominant in all the areas and comprised 82.5 per cent of the total weight taken, while game fish comprised only 3.0 per cent, pan fish 9.6 per cent, and food fish 4.9 per cent. This predominance of the coarse species coupled with a decline of the game species indicates that the coarse fishes are increasing at the expense of the game species. A commercial fishery in these waters would be valuable, therefore, not only for furnishing an estimated annual yield of 22 million pounds of fish for which there is a great need during the present emergency, but also for controlling the coarse species. There are, however, several problems to be solved before a commercial fishery can be established in these reservoirs. Among these problems are the removal of legal restrictions on netting, the development of a market for the coarse species, and the discovery of profitable methods for taking fish. It is hoped that legal restrictions on netting will be removed in the near future by legislative action of the states concerned. Due to the present emergency there is now a market for several of the coarse fishes such as carp and buffalo for which there is a very limited demand during normal times. Those species, such as gar, shad, and mooneye, which are not in demand for food can be utilized along with the offal from the edible fish for the production of fish meal and oil. Experiments conducted to date indicate that their use in this manner is both practicable and profitable. Studies to determine the most feasible fishing methods indicate that fyke nets and gill nets are of limited value for the taking of coarse fish, except in certain localities and at certain times. Large-mesh gill nets are quite effective for several species and are especially good below the dams. Seines have to date given the best returns, but their use is restricted to areas free of stumps and other obstructions. While the problem is yet to be solved it is probable that if legal restrictions on netting are removed the fishermen will devise ways and means of taking the fish. It is believed that through the use of several types of gear at different times, or for different species, it will be possible to carry on a profitable commercial fishery in the TVA reservoirs. Such a fishery must be managed, however, so that the even less desirable species, such as gar, shad, and carpsuckers, do not become dominant in the event that carp and buffalo can be controlled.

Research Items

Management of Small Artificial Lakes GEORGE W. BENNETT gives a "Summary of Fisheries Investigations, 1938–1942" on this subject (Bull Illinois Nat. Hist. Surv., 22; 1943). The primary objective of fish management is to produce and maintain good fishing. The author defines 'good fishing' as including the element of numbers of fish caught for unit of time or effort, as well as that of size of individual fish. There is much to be done in maintaining these small artificial lakes, and this report gives a valuable summary of researches. The best fishes for these Illinois artificial lakes are large-mouth bass Huro salmoides, white and black crappies Pomoxis nigro-maculatus, bluegills Lepomis macrochirus and black and yellow bullheads Ameiurus natalis natalis. Other fish are apparently of little value in hook-and-line fishing. The chief causes for poor fishing are past improper stocking, large population of rough fish or other fishes of little use for angling, and stunting as a result of over-population. Lakes should be cropped in order to produce and maintain good yields. A cropping plan should include measures to control the numbers of fish of small size as well as the total poundage of large fish taken by anglers. Simple combinations of fishes tested to determine their value for angling shows the bass-bluegill combination to be one of the most satisfactory.

The Growth of the Large Mouthed Black Bass, Huro salmoides (Lacepede), in the Waters of Wisconsin

A GREAT deal of careful research has been published, during the last ten years, dealing with growth stpdies of fish. Nearly all of these studies have been based upon material collected either by the scientific worker and his staff (using nets) or upon material obtained by the scientist from the catches of commercial fishermen. These publications cover a large number of species, both among those considered of economic importance as food fish and those of lesser direct economic importance, often classified as rough fish and minnows. However, a brief survey of these publications brings to light the fact that the fish of greatest importance to the fishing public, namely those classified as the more important game species, have been partially neglected. The reason for this is obvious. Game laws restrict these species from the catches of commercial fishermen in nearly all of our inland lakes. Although the scientist is less restricted in his activities, he feels that to kill a large number of important game fish in lakes frequented by fishermen would arouse adverse public opinion, perhaps to the extent that his own activities might be curtailed. As long as the game fish rank first in importance to the public, they should in no way be neglected, although the worker must resort to new methods of obtaining the desired data. With the purpose of obtaining materials for gamefish growth studies, the Wisconsin Conservation Department, the U. S. Bureau of Fisheries, and the Wisconsin Geological and Natural History Survey (in 1928) requested anglers to cooperate with them by sending in scales from their catches, along with accurate measurements of lengths and weights, determinations of sex, and the lake from which the fish were taken. As soon as this request became widely known, the cooperation was hearty and to date a large amount of data has been collected, not only from the five most important game fish species, i.e., Esox masquinongy, E. lucius, Stizostedion vitreum, Huro salmoides and Micropterus dolomieu, but also much material from some of the less important species, namely, the bluegill, rock bass, white bass, and trouts. Since this type of collecting has been in progress, four general reports have been published (mimeographed) (Juday and Schneberger, 1930 and 1933, Juday and Bennett, 1935, Juday and Schloemer, 1936). At the present time, enough materials are available for more detailed reports upon individual species. The first of these, dealing with the growth of the muskellunge in Wisconsin, is already published (Schloemer, 1936). The recent trend in fisheries biology research is toward fish management,