Journal of the Southeastern Association of Fish and Wildlife Agencies

Thirty-six immature alligators (Alligator mississippensis) collected from a canal in the Everglades were examined for information on summer food preferences. A snail (Pomacea paludosa) comprised 65.8 percent by volume of the stomach contents. Invertebrates accounted for 98.0 percent by volume of the total stomach contents.

Establishment was not attained during a six-year intensive investigation into the factors influencing survival of liberated pen-reared Reeve's pheasants in Kentucky. During the tenure of the study, 6,815 juvenile and 859 adult Reeve's were liberated in a varie~ of habitat composition at seven pre-selected release areas. The sex ratIo of release stock was 93 cocks per 100 hens. To enhance field identification, all liberated pheasants were marked with plastic neck tags and metal leg bands. The total recorded mortality was less than two percent of the number released. Approximately thirty percent of the known fatalities was attributed to predation. Avian and fox predation accounted for most of predatory fatalities. Ten broods averaging almost ten chicks per brood were reported. Some evidence was found to indicate a "drumming" display by adult male Reeve's may be associated with reproduction.

Laboratory studies to determine the effect of striped bass egg sedimentation were conducted and a mean hatch of 35.7 percent was recorded for eggs placed on coarse sand while eggs placed on plastic had an average hatch of 36.4 percent. In comparison, the average hatch on silt-sand was 13.1 percent and 3.2 percent on silt-clay-sand substrate. None of the eggs deposited on a muck-detritus substrate hatched. Further egg studies indicated that the percent hatch improved with the period of time eggs were suspended prior to sedimentation. Preliminary observations concerning white bass egg development and notes useful in approximating the time of ovulation are presented. Larvae from the striped bass female X white bass male cross are compared with larvae resulting from the reciprocal cross (white bass female X striped bass male).

Striped bass, Roccus saxatilis (Walbaum), have been reported along the Gulf Coast from Florida to eastern Louisiana. This fish has been found in all major river systems along the Mississippi Gulf Coast from the Pascagoula River west to the Tangipahoa River. The striped bass population in the west Pascagoula River supports a small sports fishery and it is the only one that consistently yields fish from year to year. The Pascagoula fish range in size up to 32 pounds in weight. In the last two years striped bass from 7 to 28 pounds have been taken in February and early March and many of the larger fish contained roe. The population level in the other rivers appears to be too low to maintain a sports fishery.

Data gathered at the Weldon Striped Bass Hatchery, Weldon, North Carolina, during the years 1960-1967 indicated that the optimum spawning temperature range for striped bass in the Roanoke River was between 62" F. and 67" F. The minimum recorded temperature at which spawning has occurred was 55" F. and the maximum was 71· F. Preliminary bioassays conducted at the hatchery during the 1967 spawning season substantiated this optimum temperature range, and further revealed that at temperatures of 74" F. to 80· F., the percent hatch dropped from 80 to 60 and the frequency of dead and malformed fry increased from 48 percent to 100 percent. At these higher temperatures, none of the fry, normal nor malformed, survived for more than 70 hours after hatching. Eggs incubated and hatched, and fry held, in water at 70" F., evidenced no mortality for 76 hours following hatch. The bioassays also revealed that at water temperature ranging from 60· F.

During the spring of 1967, 240,000 striped bass and striped bass X white bass hybrid fry were stocked in four one-acre dirt ponds. Each pond received 30,000 striped bass and 30,000 hybrids. At the end of a 71-day period, approximately 23,187 were harvested in three ponds, 12.88 percent of ,the original number. A total kill occurred in the fourth pond one week prior to harvest. Results indicate the hybrid having faster growth and higher survival rates.

Commercial catch statistics for brown shrimp (Penaeus aztecus Ives) from a restricted area along the Texas coast were examined by using the virtual population technique. The sum of all catches from a single year class was used as a minimum estimate of population size at the time of recruitment. The conversion of catches from pounds to numbers also made possible maximum estimates of the exploitation rate for all periods after recruitment. Monthly catches of shrimp of each size group were compared for the years 1961-66, and weights were converted to value by using the mean price per pound for each size group for the period. Comparisons of the percentage of a year class harvested at each size with the percentage of the gross value contributed by each size group may aid in making decisions concerning the management of shrimp stocks.

Analog computation and simulation involves the use of an electronic computer in which scaled voltages represent physical variables. This computer solves differential equations to simulate time related systems. Simulation of Von Bertalanffy's equation representing growth in length or weight is a simple procedure. Change of constant values enables a rapid adaptation and fit to a given set of growth data. A check on age analysis by using length-weight plots may be possible with this computer. An example of its use in analysis of striped bass growth is given.

Pink or spotted (Penaeus duorarum) , brown (P. aztecus) , and white (P. setiferus) shrimp, marked with biological stains and fluorescent pigments, were released in nursery areas tributary to the Core Sound and Lower Cape Fear River estuaries in Nor·th Carolina to obtain information concerning population dynamics including movement and migration patterns. A combined total of 26,989 pink, brown, and white shrimp was marked and released from April to October, 1966. Of these, 1,671 or 6.2% were returned. The combined average interval between release and recapture was 17.5 days, and the average distance traveled was 0.5 miles per day. Data indicated that size distribution "levels of equilibrium" were reached in individual nursery areas, whereby the size frequency modes increased to characteristic levels and subsequently remained at these levels during the study of each species. With few exceptions, all "inside" movement was toward waters of higher salinity.

The voluminous amounts of biological information collected for the Mississippi Estuarine Inventory required the development of a system for the automatrc processing of this data. The prime requirement of such a system was preparing a taxonomic code that could be easily updated and efficiently handled by EDP equipment. A modified version of the phylogenetic taxonomic structure was used to reduce the extent of the code and make optimum use of computer time. By the use of several search algorithms, computer memory requirements were substantially reduced. The utilization of the coded input to present an output with scientific names rather than code eliminated the undesirable need for double reference. The necessity for the biologist to be involved directly with the processing is eliminated, thus freeing him to devote his talents to the comprehensive interpretation of the results.

The growth of the Pacific herring (Clupea pallasii), lake sturgeon (Acipenser fulvescens) and white sturgeon (Acipenser transmontanous) is analyzed by the application of Parker-Larkin and Von Bertalanffy equations. The physiological significance of the parameters of the ,two equations is discussed.

During the process of a biological sampling program for Mississippi's Estuarine Inventory, data on the spawning season and influx of young were compiled for the two species of silversides found in Mississippi estuarine waters, Menidia beryllina (Cope) and Membras martinica (Valenciennes). Silversides taken from collections made with seines, beam trawls, plankton nets and dip nets were measured and the condition of the gonads noted. These data, when combined with associated field observations, first revealed ripe male and female Menidia beryllina (68 mm to 98 mm) in late March (water temperature 23.9°C) and Membras martinica (66 mm to 79 mm) in early April. M. beryllina in spawning condition were collected in salinities ranging from 3.6'/00 to 31.5%0 and water temperatures ranging from 23.9°C to 32.7·C throughout the spring and summer months. Spawning M. martinica were collected in salinities from 9.4 °/00 to 31.1·00 and in water temperatures from 21.2·C to 30.7°C.

Severe reduction in number of river redhorse, Moxostoma carinatum (Cope), has occurred in Alabama and the southeast during recent years. The Cahaba River is one of the last strongholds for this species in Alabama. Electrical shocking equipment was utilized during this study. Two hundred eighty-six adult river redhorse were captured, tagged, and returned to the Cahaba River. Redhorse were observed spawning on gravel shoals during April, 1966 and April, 1967 with water temperatures ranging from nOF. to 76° F. Egg counts made on river redhorse ranging in size from 17.9 inches to 22.1 inches total length revealed a range from 6,078 to 23,085 eggs per individual, respectively. Pond-reared river redhorse exhibited slower growth than those in natural habitats. River redhorse fed heavily on the Asiatic clam, Corbicula 8pp. Present utilization of the river redhorse as a sport fish is light.

Stomach contents were examined from 1,288 longear sunfish, 827 green sunfish, 1,099 bluegill, 246 largemouth bass, 144 smallmouthbass, and 304 spotted bass collected from shoreline areas of a reservoir in the process of filling and from one 15 years old, during and following bass spawning, 3 May-25 June, 1965. Young-of~the-year and bass 8.0 inches or more in length are not included. This study suggests that in the new reservoir the food supply was ample in relation to the centrarchid population demand. In the older reservoir the opposite was true, resulting in more efficient utiliz3ltion of all available foods, including appreciable quantities of bass eggs and young. However, availability was influenced to a marked extent by size of predators and prey as well as abundance. The result was food "skimming," whereby the larger fish usurped the tendipedids and large cladocerans, leaving only smaller prey available for newly hatched largemouth young.

The spawning behavior, age and growth and food habits of white bass, Roccus chrysops (Rafinesque), were studied in Center Hill Reservoir, Tennessee, from October, 1965 until March, 1967. White bass began to move toward the headwaters in late February and early March when water temperatures rose above 45° F. Spawning started in mid-March at a water temperature of 53° F. and appeared to stop if water temperature dropped below 53° F. The duration of the spawning season was one and one-half to two months. The growth rate of white bass was more rapid than in other waters. The maximum age of white bass in Center Hill Reservoir is eight years. The primary forage species for adu1t white bass were shad, Dorosoma spp.

Fingerling spotted gar, Lepisosteus oculatus (Winchell), stocked at rates of 100 and 148 per acre into four Alabama ponds containing bluegills, Lepomis macrochirus, and fathead minnows, Pimephales promelas, failed to control crowding of bluegill within a 22-month experiment. Plastic-lined pools stocked with adult gar and equal numbers of bluegills, golden shiners, Notemigonus crysoleucas, largemouth bass, Micropterus salmoides, and white catfish, Ictalurus catus, showed the least reduction in numbers of bluegill, followed by golden shiners, white catfish, and largemouth bass. An emaciated condition that developed in the largemouth bass may have contributed to their vulnerability.

The position of Bull Shoals Lake as the lower lake in a chain of four large reservoirs located on the main stem of the White River in Arkansas and Missouri is described. During the three years of 1961, 1962, and 1963, physical-chemical determinations were made at three sampling stations situated along the channel of the lake. Trout requirements with respect to tempera,ture and dissolved oxygen as reported by other authors in the Southeastern United States are reviewed. Data collected showed that trout could survive year 'round in the vicinity of all stations. Concurrent experimental stocking of tagged rainbow trout, Salmo gairdneir** (Richardson), and tag returns during this study are discussed.

Physico-chemical factors, plankton, benthic macroinvertebrates, and fishes occurring in cold tailwaters below Beaver, Bull Shoals, and Norfork dams in northern Arkansas, were sampled regularly from July, 1965, through December, 1966. Physico-chemical conditions were similar in the three tailwaters throughout the study. The older tailwaters below Bull Shoals and Norfork dams were more productive than the Beaver tailwater in both phytoplankton and zooplankton. The greatest number of genera of plankton occurred in the Beaver tailwater, and the Bull Shoals tailwater had the least number. The majority of the benthic macroinvertebrates was comprised of only a few taxa. Samples from the Norfork tailwater contained more organisms and a higher average wet weight per square foot than did samples from the other two localities.

In Louisiana, the yo-yo fishing method has been a controversial fishing method. The yo-yo is an automatic spring loaded device equipped with a hook and when triggered by a fish will automatically set the hook and play the fish. During this project, 9,203 yo-yos were fished. The average success was 0.161 fish per effort. Approximately 21% of the yo-yos fished were tripped but caught no fish. There was little difference between day and night fishing successes. The devices were fished most efficiently during February and March. Best depths for fishing were between three and four feet. The use of sinkers greatly reduces the effectiveness of yo-yos. Based upon data gathered during this project, the yo-yo is not so efficient as popularly imagined to be and, there is no evidence that it should not be a legal fishing device.

Three lots of 6-day-old to IPh-month-old channel catfish from a common initial source but reared under different thermal conditions were utilized to investigate several heat-tolerance relationships. During the experimental period the fish were held in constant-temperature tanks and samples of fish were subjected to a range of sub-lethal and lethal temperatures in test baths. The results were studied by plotting time to death of individual fish and means of test samples on semi-log paper, probability paper in some instances, and subjecting pertinent data to statistical analysis. Fish acclimated to 26.0, 30.0, and 34.0C had upper lethal temperatures of approximately 36.6, 37.3, and 37.8C respectively. Differences in resistance times were related to age but not to size.