A COMPARATIVE STUDY OF BRACKISH WATER FISHES A COMPARATIVE STUDY OF BRACKISH WATER FISHES THESIS Presented to the Faculty of the Graduate School of The University of Texas in Partial Fulfillment of the Requirements For the Degree of MASTER OF ARTS Robert James Kemp, Jr., B.A. Austin, Texas THESIS Presented to the Faculty of the Graduate School of The University of Texas in Partial Fulfillment of the Requirements For the'Degree of MASTER OF ARTS by Robert James Kemp, Jr., B. A. Austin, Texas May, 1950 PREFACE The writer wishes to express at this time his appreciation to Dr. W. Frank Blair who suggested this study. Without his patience, suggestions, and timely criticisms, this paper would not have been possible. Acknowledgement should be made to Mr, Clark Hubbs for his invaluable aid in collecting and identifying specimens. and for his directing the major portion of this work. Thanks are also due Dr, B. C. Tharp for his help in identifying botanical specimens and arranging that section of the study. The writer also wishes to express his appreciation to Mr. J. L. Baughman, Chief Marine Biologist of the State of Texas, for providing facilities at the Marine Laboratory in Lockport. TABLE OF CONTENTS CHAPTER PAGE I. INTRODUCTION J 11. NINE MILE POND 6 History Physical Characters Chemical Characters Vegetation Fishes Other Vertebrates Invertebrates 111. TULE POND 25 History Physical Characters Chemical Characters Vegetation Fishes Other Vertebrates Invertebrates IV. TULE POND INLET 36 V. YEĹLOW POND 38 VI. SHALLOW POND 40 VII. SUMMARY 40 VIII. LITERATURE CITED 44 IX. VITA 45 INTRODUCTION Very little has been published on the brackish water fishes of the Texas Coast, and for this reason this study was undertaken. The brackish water ponds are unique in that seldom are two ponds encountered that have the same salinity. Thus each pond presents an ecological association all its own, with different plant and animal life present in each. Salinity of the water has been arbitrarily chosen as the controlling factor here. The ecology of each pond is probably governed by a combination of factors, but salinity is undoubtedly a major factor, and certainly one that can be measured and compared. Live Oak Peninsula was chosen for the site of this work because of the numerous ponds scattered throughout its length, and because of its accessibility to the Rockport Marine laboratory. The main body of this work was carried out on two ponds. These were Tule Pond, of very low salinity (very nearly fresh water), and Nine Mile Pond, of relatively high salinity. Two other ponds and one flowing stream were checked, but not intensively studied. This study centers around fish, but in addition a fairly complete ecological survey was attempted. The plant and invertebrate life have been covered to some extent. Fig, 1. Sketch map of Rockport area and Live Oak Peninsula. NINE MILE POND Nine Mile Pond was chosen for this study because of its relatively high salinity and its all-around physical characters. It is located on Live Oak Peninsula in Aransas Co., Texas, just five miles north of Rockport, as can be seen on the map of the area (Fig. 1). The distance from the nearest part of the pond to Aransas Bay is approximately thirty-five feet. This pond was studied during three separate periods. The first was in July and August, 1949? when frequent collections were made. In October, 1949? a spot check was made. In April, 1950, intensive collecting was carried on night and day foxthree days. The general character of the area is shown in Plates 1 and 2. History The history of Nine Mile Pond began in 1940. An oil company decided to drill a well in a slight depression where Mine Mile Pond is now located. A large hole fifteen to twenty feet deep was dredged out, and a channel from the bay was opened in order to float in a drilling barge. Drilling operations were carried on about six months, and then the well was abandoned. All traces of the drilling have disappeared, except for submerged machinery and cables, and Nine Mile Pond has all the appearances of being a naturally formed pond. The opening to the bay was closed by wave action a few months after the drilling ceased. High tides caused the bay to overflow into the pond until the opening was completely sealed. Storm tides caused the pond to be flooded in September, 1946, and again in September, 1949. In September, 1948, a class in vertebrate taxonomy from the University of Texas made several collections from this pond. The fish collected by seining at that time include the following species ; Paraljchthys sj). - Fluke Fundulus grandis Baird and Girard - Common Killifish Lucania venusta Girard - Pretty Killifish Menidia sp. - Silverside Opsanus beta Linnaeus - Toadfish Gobiosoma so. - Goby The large shrimp penacus amtecus was taken, along with the Mantis shrimp, Seallla empusa. (These fish and shrimp identifications were made in the field by class members.) Physical Characters Nine Mile Pend, being man made, has a fairly regular shore line approximately 8?0 yards long. The pond has the shape of a large L. The area covered is approximately 3,100 square yards or 0.6? acres. . The depth of Hine Mile Pond varies from just a few inches in the extreme north end to ten to twelve feet in the center. The depth contour is shown in Figure 2. The banks of the pond are steep and rapidly drop off to deep water. The bottom is made up of oyster shell and mud, with overylying silt in the deeper water. The temperature of the water at the surface varied from 2,0° to J.o° C. higher than that of the water six feet below the surface. The water was fairly clear. Water samples allowed to stand twenty-four hours, showed a slight amount of sediment settled out the end of that period. Fig. 2. Depth Contour Map of Nine Mile Pond Chemical Characters The salinity of Hine Mile Pond, when taken in July and August, 1949, varied from 19*9 to 21.5 parts per thousand. These were calculated by the hydrometer method. In April, 1950, a titration method was used, the salinity was found to be 18*3 parts per thousand. The dissolved oxygen content of the water was measured by the Rideal-Stewart modification (Therous, Eldridge, and Kallmann, 1936). Due to awkward handling of the reagents, the results were too inaccurate to report* The results did Indicate a relatively high oxygen content* Vegetation Nine Mile Pond,, located just a few yards from the Aransas Bay beach, is in the midst of a mesquite grassland* In the pond and around its margins were found nine species of plants, all collected in July and August, 1949* Figure 3 shows the approximate location of these species. The plants found were as follows: 1* Bacona monnjera (L) Britton 2. Batis maritima L. 3* Borrichia fratescens (L) DC 4. Cyporus sp. 5* Dichromena color ata Michx. 6. Eustoma gracile Engelm. 7“ Hydrocotyle bonariensis Lam. 8. Pas pa I m Swartz 9* Spartina altern!flora Lois. Baeopa monnicra was found growing rather abundantly along the south, east, and west sides in water up to twelve inches in depth. Batis maritime, a strand shrub, was very abundant. It was found growing in water up to six inches deep in all parts of the pond. Bornichla frutescens, a seashore shrub, was found growing sparsely on the east and west banks. Cyperus hp. 5 a member of the sedge family, was abundant in the shallow water along the south, west, and east banks. Dichromena colorata, a perennial sedge characterised by involucral bracts having a very handsome base of white, was found only in one place: a single clump approximately two feet wide and six feet long was found growing in the sand and shell along the bank of the extreme eastern corner of the pond nearest the bay. Eustoma an annual herb, was found growing on the east and west banks along with B. frutescens. Hydrocotyle bonariensis, a perennial herb, was very restricted. It was found growing in water up to a foot in depth in the eastern corner of the pond nearest the bay* The area covered by this species was approximately two feet wide and fifteen feet long. Pasnalum vaginatun, a perennial seashore grass, was the dominant species. It was found in shallow water in all parts of the pond. Spartina alterniflora, a tall, perennial salt-marsh grass. was not common. A single clump three feet wide and fifteen feet long was found in shallow water along the north-west shore. This brief study of the vegetation of Nine Mile Pond revealed Pasnalum vagina tun to be the most abundant species present. A dense vegetative growth has been discouraged here by the steep banks on all sides of the pond which rapidly slant off to water, which is apparently too deep for plant growth. Fig. 3. Vegetation chart of Nine Mile Pond. 1• Baeopa monnicra 2* Batis WUlltlEia 3. Borriehia 4, Oy a eras sp. 5- £X.cfaomena colored 6 • bOMa /cx*ac xXe 7* HydrocotyIe bonayionsiff Paspalum vagina tun, 9• Snartina aIternlflora Fishes -—f The study of Nine Mile Pond centered primarily around the fish found there. The fish were taken by seining and trapping. I—— Seining was accomplished with several types of seines® In July and August, a fifty foot common sense minnow seine was used, and in October, a twenty foot seine of the same type was used. For the April, 1950, collecting, a twentyfive foot bag seine with 3/8 inch mesh on the wings and 1/4 inch mesh in the bag was used. Trapping was done by means of crab traps in July and August, 1949* These traps, described on .page 24 were baited with dead fish and dead crabs. <—j By use of these various modes of collecting, a total of 8,100 fish was taken. These included the following thirteen species: 1. Anguilla bostonionsis (Le Sueur) 2. Lucania venusta Girard 3. Adinla nultifasciata Girard 4. Fundulus similis Baird and Girard >«i.i 'HWW g.-«Wr»-s*«.TOa •* MM.•• I •.’■.L «. - ~ 5* Fund ul ns r: rand is. Baird and Girard 6. Fundulus pulvereus Evermann 7. Cyprinodon variegatus varieg atus Lacepede 8* Mollienosia la tip lima (Le Sueur) 9- Mouldla beryl!ina Copa 10. Mug 11 ccnhalus Linnaeus 11. Opsanus beta Goode and Bean 12. Dormitator Bloch 33* Gobiosoma boset Lacepede The numbers of each individual species taken are shown in Table I. The comparative numbers of fish taken in daytime and at night, and in shallow and deep water may be seen in Table 11. As soon as possible after capture, all the fish were placed in a ten per cent formalin solution for preserving. Later, in the laboratory, the fish were sorted, identified, and counted. Approximately half the fish taken were measured for standard length in mm. by using dividers and a ruler. (All of the fish measurements made in this study were standard length.) All of the species of fishes found in Hine Hile rond are included in the following annotated list. UhaXl Striped Mullet This is the common mullet found in great abundance in the Atlantic and Pacific oceans, in the Gulf of Mexico, and along the coasts of Southern Europe and Africa. Gunter (1945) reported the mullet to be found in all salinities of water along the Texas Coast. It is described as reaching a length of two feet and over. In Hine Mlle Pond ceuhalus could be seen at the surface in schools of several hundred, all of which appeared to be approximately twelve to fifteen inches in length. Due to the fact that this pond was quite deep and there was very little shallow water along the margins, it was impossible to collect this species in any quantity. Thus, no estimate of the relative size of the population was obtained. Even though it was probably outnumbered by several other species. M, cephalus would bo the dominant species here if dominance were judged by mass alone. The total bulk of this species probably was by far the greatest of any fish in this pond. Cyprinodon veriest us. Broad Killifish This member of the Killifish family has a very short, stout body with an elevated back. The males are described as being blue-green in color, with a black band across the tip of the caudal fin. The females are light green with i several crossbars on the back. The male reaches a length of three inches (seventy-five mm.) and the female two inches, (fifty mm.) according to Jordan and Evermann. Gunter reported (1945) one specimen ninety-three mm. long but this nay have been total length and not standard length. This species is readily found in fresh and brackish water alike. In July and August, 1949, £. yariegatus was the most numerous of all the species. The 3,139 specimens made up eighty-two per cent of the total sample taken in both day and night collections# In October 25, 1949, a spot-check of this pond in the daytime showed Ch variehatus to make up only 7*3 per cent of the 111 fish taken. On April 6 and 7, an equal amount of nocturnal and diurnal collecting produced the following results: ?02 C. variogalus taken at night, against 206 taken during the daytime* Of the total of 903 specimens, 758 were taken in water over five feet in depth. This indicates that C. yariegatus tends to be nocturnal in habit and prefers fairly deep water. The 908 specimens made up 21*8 per cent of the total number of fish taken in April, 1950* Ihis was a great decrease in. frequency from the previous summer. Scales from various size groups of C. yariegatus were examined for annual rings, to see if the fish could be placed in age groups. However, no annual rings were found on any of these scales. The stomachs from ten C. variegatus were examined for food content. All stomachs were found to contain either algae, bits of vegetation, or both. This indicates that C. yarlegatos, is primarily, if not entirely, herbivorous* Adinia multifasciata. Banded Killifish This killifish has a short, deep body, similar to the much more common C. variegatus * The male is described (Jordan and Evermann, 1896) as being dark green, with ten to fourteen narrow pearly barXs on the sides. The female is greenish with a few pale cross bands. It is said to reach a length of two inches (approximately fifty mm*) Adinia is not known to enter fresh water. Adinia was among the rarer fishes found in July and August, with only eleven specimens found there* These ranged in size from a minimum of twenty mm* to a maximum of twenty-seven mm* standard length. This falls within Gunter’s (1945) twenty to thirty-five mm. range* A single specimen was taken in October, 1949. In April, 1950, 271 A. m ultifa scia ta v/ere taken, showing a large population increase, all ranging from twenty-one to thirty mm. in standard length* Only five of these were taken at night, while the remaining 266 were taken in the daytime* All but thirty of the 271 specimens were taken in water over five feet in depth. This definitely shows A nultifasciata to be diurnal in habit and to prefer deep water* The 271 specimens made up 6.4 per cent of the total population taken at this time. , Lucania venusta* Pretty Killifish Lucania venusta is a rather small fish with a compressed, oblong body, The male is described (Jordan and Lvermann, 1896) as being light olive in color, with the scales very dark edged, giving a "diamond-checked” effect* The female is similar in appearance to the male* L. venusta is found in lagoons and inlets from Florida to the Rio Grande. Gunter reported (194?) specimens up to fifty-three mm. in length. L. yenusta vias fairly common in July and August, with seventy specimens making up 1.8 per cent of the sample recorded from there. These showed a size range of nineteen to thirty-six mm., with the majority being between twenty-two and twenty-five mm. in standard length. Sixteen specimens of L. venusta were taken in October. In April, 878 L. venusta were taken, making up twentyone per cent of the population. This indicates a substantial increase over July and August. Of this number, 469 were taken at night and 409 were taken during the daytime. Only 295 specimens were taken in shallow water. From this study L. venusta can be called neither nocturnal nor diurnal, but it does show a preference for deeper water* Fundulus nrandis. Common Killifish This is the largest of the killifishes of our region, often reaching six inches or more in length. It is described (Jordan and Evermann, 1896) as having a thick, deep, oblong body shape# The males are very dark green above and lighter below, with many white spots on the sides during breeding. The fins are orange, speckled with white, producing a very beautiful fish. The females are olive and much less colorful, with fins plain. The young of both sexes have numerous narrow cross bars. This species is common to salt and brackish waters on the Atlantic and Gulf Coasts. F, grandis was second to Cyprinodon in the number of specimens taken in July and August. Thore were 348 of these killifish recorded/from Hine Hile Pond, constituting 9*9 per cent of the fish captured. The largest specimen found measured 130 mm., and the smallest was fifteen mm. The stomachs of four of these fish were opened to determine what type of food had been eaten. All four stomachs contained blue-green algae and other bits of vegetation. Since many of these fish were taken in traps baited with dead fish and crabs, F. grandis may be a scavenger In October, five F. grandis were taken. F. grandis taken in April, 1955? numbered 110 showing a considerable decrease in frequency. Of this number, thirty-three were taken at night and seventy-seven were taken in the daytime. Only five specimens were taken in shallow water (one to three feet in depth). This indicates that F. grand!s is diurnal in habit and prefers deep water. The 110 specimens made up 2.6 per cent of the fish taken. Fundulus similis. Gulf Killifish F. siinilts was the most handsome species taken. It has a slender body, much deeper in the adults than in the young* The head is much longer and the eye much smaller than in F. grand!s. The male is olive colored above and pale below, with the sides marked with ten to fifteen dark blue-black vertical bars* The female is similar to the male except lighter in color. F. similia is commonly found in brackish ponds and shallow bays from Florida to Texas. It is described (Jordan and Evermann, 1896) as reaching a length of six inches (150 mm.) F. similis was found to be quite rare, with only five specimens found there in July and August. These ranged in size from thirty-three to ninety-six mm. in standard length. A single specimen was taken in October. In April, 1950, three specimens of F. sim|lis were captured. All three were taken at night in deep water. Fluid ulus nulvereus The body of F. pulvereus is fairly stout, having a general outline similar to F. grandly. The sides of the female are described (Jordan and Evermann, 1896) as light in color and covered with dark brown spots. The male is dark green with eight to ten narrow vertical ivory bars on the sides« This fish reaches fifty mm. in length, and is found in small numbers in brackish water on the Texas Coast. F. pulvereus was the rarest of all the species found in July and August/ A single female specimen thirty-eight mm. standard length was taken on August 25, Subsequent collecting in October, 1949, did not yield this species. In April, ten specimens of F. pulvereus were collected. Five of these were taken in shallow water and five in deeper water, all during the daytime. The number of specimens were too few, however, to draw any definite conclusions. Mollienisia latininna. Sail-finned Killifish M. latininna is described (Jordan and Evermann, 1896) as having a stout, oblong body, slightly compressed. The females have a characteristic swollen belly. The male commonly has an enormously elevated dorsal exceeding the height of the body. The anal fin of the male is modified into an intromittent organ, indicating that these fish are ovoviviparous. The scales have oblong spots which give the fish lengthwise stripes on the sides. This species is found in salt, brackish, and fresh water. It reaches a length of three inches. M. latipinna was fairly common in Kino Mile Pond, with eighty-eight specimens taken there in July and August making up 2.3 per cent of the total taken. -Seven of these were males of twenty-one to thirty mm. standard length, and eighty-one were females twenty to fifty-nine mm. long. Ho good explanation of the small percentage of males found as compared to females has been given. Apparently the mortality rate of the male is much higher, and since one male can fertilize many females, it is not necessary to have an equal sex ratio. Two specimens of M. latipinna were taken in October. In April j 789 specimens of g. latipinna were captured showing a large increase in numbers over the summer months. Three hundred and four of these were taken at night and 48? during the day, while 307 were taken in shallow water- and 482 in deep water. Thus, M. latipinna showed a slight tendency towards dlurnalism and a slight preference for deeper water. The 789 specimens made up 18.9 per cent of the total number of fish taken in April. boscl. Naked Goby The body of this goby is elongate, with the head broad and flattish above. Scales are entirely missing on this species* The color is described as olivaceous with darker cross shades of rounded spots. It is said to be an Atlantic Coast fish, but was reported by Gunter (194?) and is probably found all along the Gulf Coast* It reaches a length of fifty mm. » G. bosci was not uncommon in July and August. The six specimens collected here measured twenty—three to forty-three mm. in length. In October, 1949, sixteen more specimens of Gobiosoma bosci were collected. In April, 1950, 105 specimens of G. bosci were taken showing a great increase in frequency, all measuring between nineteen and forty-five mm. standard length. Of these, seventynine were collected at night and twenty-six during the day, with seventy-one found in deep water and thirty-four in shallow water. This indicates that G. bosci may be nocturnal in habit and that it prefers deeper water. Oosanus beta• Toad fish The body of the toadfish is short, robust, and scaleless. The head is broad and flat, and the mouth is wide with powerful jaws, Two spines on the opex*cle and three spines on the dorsal, fin contribute to the fierce appearance of this fish. The coloring is dusky brown with black markings forming indistinct bars on the sides* Shallow water specimens are supposed to be nearly black, while specimens from deep water arc much lighter in color. The toadfish is abundant all along the Atlantic and Gulf Coasts. They are said (Jordan and Evermann, 1816) to reach a length of fifteen inches (approximately 375 mm.). Cofhnus beta feeds primarily on crustaceans and mollusks. Opsanus beta was fairly common in IJine Hile Pond. The nine specimens taken there in July and August measured between twenty-five and 183 mm. Both the light brown and the near-black color phases in this species were found. This indicates that color variation may bo based on something other than the depth of the water, as related in ”Jordan and Evermann”. It is quite possible that the light stock originated on sandy bottoms while the darker fish came from waters with dark vegetation. In October, seven more specimens of Opsanus beta, were collected* In April, sixteen other 0. beta were captured. Ten of these were taken at night and six in the daytime, while twelve ’were found in water over four feet deep and only four were taken in shallow water. Menidia beryllina* Tide-water Silversides IK beryllina has the shape of a typical silverside, with an elongate, compressed body* The eye is quite large. The color is light green, with the silvery band underlaid by black* This species reaches a length of four inches (approximately 100 mm*;* It is commonly found along the sandy beaches of the Gull’ Coast, and will frequently enter fresh water* Gunter reported (194?) this species in all salinities* 11. beryllina was abundant during July and August, with 149 specimens recorded. These ranged in. size from a maximum of eighty-four mm. standard length to a minimum of twenty-one mm. and made up 3.7 per cent of the sample. In October, this species was the most common one in Nine Mile Pond, with fifty-four being taken. In April, 1950, M. bcrxllina was found to be the most abundant of all the species. The 1066 specimens made up 2J.6 per cent of the number of fish taken at that time. Of this total, 891 were taken at night and 175 during the day. Only twenty specimens were taken in shallow v/ater. L- — Dormitator maculatug. Sleeper The sleeper is a member of the goby family, but has the general body shape of Fundulus grandis. It is found in both fresh and salt water, and is said (Jordan and Evermann, 1896) to reach a length of over one foot. A single specimen of D. maculates was captured the night of April 7,19 JO in a bag seine in eight feet of water. It measured eighty-six mm. standard length. This was the rarest species encountered# Anguilla bostoniensis. Common Eel The common eel. is an elongate, snake-like fish, without scales and without pelvic fins. It is blue-grey in color and reaches a length of four to five feet (Breder, 1948) b. bostonlensis was probably quite common, even though it wasn’t collected until April 7$ 1950- specimens were taken in a bag seine, and one was.taken on hook and line. The size range was approximately IpO mm. to 630 mm. standard length. The specimen taken by hook and line was 570 mm. long. The young specimen approximately 150 mm. escaped after being brought up on the beach. Another small eel was seen in shallow water at another part of the pond the same night. The stomachs of the two large specimens were opened for food content. One stomach contained a Callinectes danac (crab) 60 mm. broad and one small shrimp. The other stomach contained the large shrimp that had been used for line bait. A* bostonionsis is probably the chief predator species in this pond. July-August 1949 October 1949 April 1950 Totals Adinia multifasclata 11 1 271 283 A n% ui 1 la b o s t o ni ens i s 0 0 3 3 Cyprinodon variolatus 3,139 8 908 Doraltator maculatug 0 0 1 1 Fundulus arendis 348 5 110 463 Fund ulus nulver eus 1 0 10 11 Fund ulus simi1is 4 1 3 8 Gobiosoma bosei 6 16 105 127 Luconia venusta 70 16 878 964 Menidia buryIlina 149 54 1,066 1,269 MoIlienisia latipInna 88 2 789 879 Mug11 cenhalus 2 1 2 5 Opsanus beta .2 7 16 32 3,827 111 4,162 8,100 Table I Numbers of Fish Taken at Nine Mile Pond, Cyprinodon Adinia 1 Lucania Fund ulus Fund ulus Fund ulus Mollicnis ii Nocturnal variegatus mult ifas ( 2lata venus ta grand is similis pulvcr eus latipinna Shallow 138 3 115 3 — Mt 133 Deep 564 2 354 30 3 ✓ 171 Total «M *<9 UW «M« 702 ■Mt «■» *•» 5 469 MW AMI «M»«W 33 MM «N« «*» M W 3 0 304 Diurnal Shallow 12 27 180 2 207 Deep 194 239 229 75 ma 5 M>a m» |«W «MM Mir 273 Total 206 266 409 77 0 10 485 Grand Total 908 271 878 110 3 10 789 Nocturnal Gobiosoma bosci Opsanus beta Menidia* Dormitator beryIlina maculatus Anguilla bostoniensis Mugil cephalus Shallow 24 1 19 0 0 2 Deep Total 55 «M» «■ *4* «M» tH 79 9 MM «MR «M« 10 872 891 1 1 3 •Mt am <M W* 3 0 «v» rtK> «m «a» 2 Diurnal Shallow 10 0 1 0 0 0 Deen X Total 16 26 3 6 174 MUM 175 0 ** MM **** 0 0 ■MmtMtMim 0 0 ma «w IMM MKC 0 Grand Total 105 16 1 S O66 1 3 2 Table II. Comparative numbers of fishes taken in daytime and night collecting and in shallow and deep water* at Nine Mile Pond. Other Vertebrates Amnhibiar»s: A single frog was seen at Nine Mile Pond. In October, 1949? a Bana Dinier.s was seen in the shallow water along the southwest shore. Heavy rains at that time had probably lowered the salinity of the surface water considerably. Reptiles; No reptiles were found in the water. However, one Lanpropeltis p;etul us (king snake), one Holbrookia pro pine ua ? and one Terras one Carolina (box turtle) were found within ten feet of the edge. Birds; Several species of shore and wading birds common to the area were seen at Nine Mile Pond at one time or another, but no attempt was made to identify them. Bucks were seen on two occasions. Mammals: Large tracks tentatively identified as Raccoon (ProcyoiA lotor) were often seen along the water 1 s edge at the shallow northern end of the pond. This mammal probably caught fish regularly here for a part of his diet. Invertebrates Crabs : Crabs found hero were taken by seining and trapping. The crab trap used was the box type with one half inch wire mesh over a steel frame. The trap measured one foot by throe feet by three feet and had small funnel openings at each of two opposite sides. Callinectcs sanidus (Blue Crab) and Callinectes danae were taken many times in seines but were not counted * The traps, baited with dead fish, produced sixteen C. sapidus during four trap nights, or an average of four crabs per trap night. The sex ratio was even, with eight adult males and eight adult females. .r These adult Blue Crabs were measured for the distance 1 from spine to spine, and also for the distance from front to back of the shell. The average measurements were respectively 171.9 am. and 77*1 mm., with a maximum of 192 x 87 mu. and a minimum of 137 x 67 mm. Two of the C. saoidas were sponge crabs, or egg-bearing females. The salinity of Nine Mile Pond at that time was 19*99 parts per thousand. F. M. Daugherty, Jr. of the Rockport Marine Laboratory, reported orally that no sponge crabs were found in salinity of less than 23.5 during a two year period of study. A third species of crab, Uca sp. ? the fiddler crab, was very common along the west shore of Hine Mile Pond. Shrinks Two species of true shrimp were taken from Nine Mile Pond. Pcnaeus aztecus was fairly common in the deep water. Palacompnetcs so. was present in Nine Mile Pond by the hundreds of thousands, particularly in the shallow water at night. Hundreds of these tiny shrimp were taken in both shallow and deep water. Soullla enousa, the Mantis shrimp (not a true shrimp), was probably present in Hine Mile Pond at the time of this study. Several specimens were taken in September, 1948 by a class from the University of Texas. Clams? The only clam found at Mine Mile Pond was Ensis sp., the razor clam. Most of these specimens were very small, none reaching over thirty-five mm. in length. M scellaneous: Comb-jellies (ctenophores) were plentiful in the surface waters of Nine Mile Pond. At least 100 of these transparent, globular animals were taken with the seines. TULE POND Tule Pond was chosen for this study because of its inland • —' "\ i 1 ■ location on the peninsula and its easy accessibility. It.is located a mile and a half north of Bockport on State Highway 35. It is approximately one half mile from Aransas Bay and two and one half miles from Copano Bay. r — Tule Pond was studied during July and August, 1949, and again in April, 1950. The photographs shown here (Plates 3 and 4) indicate the physical characters of the general area. The location of this pond in relation to Mine Mile Pond is shown in figure 1. History In the middle of August, 1948, W. B. Wilson seined Tale Pond to collect museum specimens for the Bockport Marine Laboratory. At that time, the pond was not ovex* a foot in depth in any place. The water extended from the fence at the south end to within ten or fifteen yards of the grass around the edge, hue to its shallowness, the ’water was very warm. The fish taken were as follows: !• Ganbnoia affinis (Top Minnow) - 300 to 400 2* Cyprinodon (Broad Killifish) - 100 to 150 3* UUEII cephalus (Striped mullet) - numerous, both dead and alive, all over six inches long# 4. Mollienisia latinlnna - 6 5° Domi ta tor maculabus (Sleeper) - 3 6. Anguilla bostoniensis <Bel) -3, (one dead) 7* Fundulus Brandis (Common Killifish) - 8 8* Lencmis sp. (Sunfish) - 2 An estimated seventy-five to 100 Blue Crabs, Callinectcs sapidus, were seined up, and many more were seen in the shallow water. Hany gulls and a number of buzzards and wading birds were seen taking both the live and dead fish. By September 1, 1943, Tule Pond had dried up completely, and remained dry until rains on September 9, 10, 11, relieved the drouth of the area. Since the pond was in. such a poor condition at the time of the seining, an accurate list of the species of fish present under normal conditions could hardly have been obtained, but it does give an idea of some of the more common fish present. Physical Characters Tule Pond is an irregular shaped body of water. The area was figured to be in the neighborhood of 9,900 square yards or 1.8 acres. The shore line is uneven, and measures approximately 1,440 yards. The depth of Tule Pond is quite uniform, varying between three and four feet in most places (Figure 4)* The bottom consists of mud and organic sediment throughout, with the exception of a relatively small area around the mouth of a stream flowing into the pond. This area has a firm bottom of sand. ... The water was turbid at all times. It was never clear enough to allow the bottom to be seen. Water samples, taken from this pond and allowed to stand twenty-four hours, cleared considerably as the silt and organic natter settled out* The pond was so shallow that the water temperature at the surface was never more than 0.7° C. higher than.the water at the bottom. The temperature difference varied from 0.4° to 0.7° C< from the surface to the bottom. Fig. 4. Depth Contour Hap of Tule Pond. Chemical Characters ; The salinity of Tule Pond was checked in August, 1949, and again in April, 1950* In August, the hydrometer method was used, and the results indicated Tule Pond to be fresh water at that time. In April, 1950, a more accurate titration method was used for salinity determination. This method showed the salinity to be 0.6 parts pox* thousand. 5 - The dissolved oxygen content in Tale Pond was checked by the Rideal-Stewart modification (Theroux, Eldridge, and Mailman, 1936). Clumsy handling of the reagents in the field made these measurements very inaccurate, but did give indications of a high oxygen content in the water of Tula Pond. Vegetation Tale Pond is located in the midst of a heavy live oak forest 5 and the vegetation in and around this pond was cense. Collecting was done during July and August, 1949# The locations of the various species may be seen on Figure 5* The species found in the pond itself and around the marshy shoreline are as follows: 1. Bacoua monnicra (L.) Britton 2. Cyoerus haspan L. 3. Dichromena colorata - (L) A. 3. Hitchcock Kote: hasoan, (2), not shovai by number on the diagram, was present throughout the entire vegetation belt except where patches of other species were found® 4, Fuircnq simplex Vahl, 5• Ridrocotyle bunariensi Lam, 6. Lemna minor L. 7* Persicqria punctata (Ell.) Small 8, Plucheq camphorata (L) EC, 9. Rynchosnora fascicularis (Michx) Vahl* 10. Bap oliis cßractiatis hBK 11. Twha angustifolla L. Bacopa monniora 5 a perennial herb? was relatively abundant * It was found extending into water one to two feet deep at various places around the pond margin* Cypc'-us haspan. a grass-like sedge, was clearly the dominant vegetation in Tale Pond. With the exception of a few small areas, this plant completely encircled the pond. It was found from marshy ground cut to water two and one-half feet in depth. Dichroncna colorata, a leafy-stemmed sedge, was not abundant, Three small clamps were found growing on the south shore. These clumps were from four to eight feet long and two to three feet wide. This species was found in water barely deep enough to cover the base of the stems. Fuirena simplex, a perennial sedge, was found sparsely growing along with Cyperus haspan, but usually in the shallower water. It was scattered at various points around the pond. Hydrocotyle bonariensis, a perennial herb with creeping rootstocks 5 was very abundant in the western half of the pond, particularly around the mouth of the inflowing stream. The plant was found in water from .six inches to a foot in depth. Lcnna minor ? a very tiny floating plant, was found in great abundance along the extreme eastern end. It was much less abundant in the northwest corner, and very sparse everywhere else. Persicarla punctata, a swamp inhabiting herb, was relatively common. It was found in circular clumps throughout the pond. These clumps were from three to six feet in diameter and were found from the marshy ground to water three feet in depth. Pluchea camphorata, an annual herb was not common. A few scattered plants were collected on the north side in marshy ground fifteen to twenty feet from open water. Rynchospora fascicularis, a perennial sedge, was another fairly common plant. It was found at many points around the pond mixed in with Cyperus * Samolus ebractiatis, a caulescent herb, was not abundant. A few scattered specimens were found on the north bank in marshy ground. Tyeha anpustifolia ? the common cat-tail, was found only in the northwest corner. Two clumps approximately ten feet long and three feet wide were found in six inches of water. This brief study of the vegetation at Tale Pond has shown at least eleven species to be present* The density of the growth indicates ideal conditions for at least the more abundant species ♦ Turbidity of the water is probably the controlling factor that prevents this shallow pond from being completely filled with plant growth. Fig. 5 Vegetation Chart of Tule Pond. 1. Bacopa monniera 2. Cyperus haspan L. 3. Dichromene colorata (L) A. S. Hitchcock 4. Fuirena simplex Vahl. 5. Hydrocotyle bonariensis Lam. 6. Lemna minor L. 7. Persicaria punctata (Ell.) Small 8. Pluchea camphorata (L) DC 9. Rynchospora fascicularis (Michx.) Vahl 10. Samolus ebractiatis HBK 11. Typhya angustifolia L. Fishes — The fishes taken from Tule Pond in July and August, 1949, were collected by means of a fifty foot common sense minnow seine and a crab trap. The following April, a twenty-five foot bag seine was used for the collecting. Collecting at Tule Pond yielded a total of 1,22? specimens. These were made up of the following eight species. 1. Luca.nl a venusta Girard 2, Fundulus urandis Baird and Girard 3. Cyorinodon variegatus Lecepede Mollienisia latininna (L. Sueur) 5* Gambusia affinis Baird and Girard 6. Henidia beryllina Copa 7• Lepomis macrochirus Gunther 8. Mugil ceahalus Linnaeus J- The numbers of each species taken are listed in Table 111. These fish were preserved and later sorted, identified, counted, and measured. The eight species of fishes taken in Tule Pond are discussed in the following annotated list. Gambusia affinis. Top Minnow The top minnow has a moderately elongate body that becomes very deep in the adult female. The head is broad and flat with a projecting jaw. Coloration is light olive with the scales dark edged. The anal fin of the male is modified into an intromittent organ, indicating this species to be ovoviviparous The males are one-half to one inch long and scarce, while the females reach a length of two inches. Gambusia is abundant in fresh and brackish water on the Atlantic and Gulf Coasts. This species has been extensively used in mosquito control. Its small size and ability to live in waters too warm or too lovz in oxygen content for most fishes make it ideal for seeking out mosquito larvae. G. affinis was very abundant in Tale Pond in July and August with 109 specimens taken there. These included 105 females measuring sixteen to thirty-nine mm* and four males measuring fourteen to nineteen mm. This species made up 19*1 per cent of the population at this time. In April, 1950, ninety-four G. affinis were captured. Of these, eighty-four were females and ten vzere males. Gambusia affinis made up 14*3 per cent of the fish taken in April, a drop of almost five per cent over the previous summer. Leponis mucrochirus. Common Bluegill The body of this sunfish is short and stubby. It differs from all other sunfish with a combination of two outstanding characters: (1) a small mouth, (2) large black spots on the posterior part of the dorsal and anal fins (Toole, 1946). It has an olive colored back with light green or lavender colored sides. This species is found from the Great Lakes to Florida and the Rio Grande. It is reported to reach a length of twelve inches, but fish over eight inches are uncommon. The bluegill was fairly common in July and August. The thirty-three specimens taken there measured from forty-one to 130 mm. Most of these specimens were under sixty-five mm. in length, and twenty-seven of these small fish were taken in crab traps. Three Lepomis macrochirus were taken in April. One specimen measured 124 mm. standard length, and the other two were thirty-nine and forty-two mm. long. This species made up less than one-half of one per cent of the fish taken in April. However, if it had been possible to do night collecting, Lepomis might have turned up in greater numbers. Mugll ceohalus. Striped Mullet M. ceahalus was fairly common, The twenty-seven specimens taken in July and August measured between sixty-eight and 131 mm, in length. The number of specimens taken would have been much greater except that many individuals of this species escaped the net by leaping over it. In April, four Hug 11 cephalus were captured. These specimens measured between 140 and 15? mm. in length. M. cephalus was undoubtedly present in much larger numbers than is indicated by the catch, but this species is extremely difficult to take with a seine. Mollienjsia latioinna. Sail-finned Killifish M. la tip Inna was the second most common species taken in July and August, 1949 5 with ninety-seven females and five males making up the 102 specimens. This species comprised eighteen per cent of the fish taken here at this time. In April, 1950, only two H. latinlnna were taken, both females. The population density of this species was obviously much lower than during the previous summer. Luc ania v enusta Lucania yenusta was not common. In July and August, only eighteen specimens were taken, these making up 3.1 per cent of the fish captured. These fish measured between twenty-six and forty-two mm. standard length. In April, 1950, the frequency of occurance of this fish had increased very little, if any. The twenty-three specimens were found within a size range of twenty-four to forty mm. Cyprlnodon variegatus C. variegatus. was another species that was not common. The forty specimens taken in the summer made up 7.0 per cent of the number of fish taken then. These measured between twentyone and fifty-two mm. standard length. In April, 1950, the rate of frequency was slightly less. The thirty-six specimens captured comprised 5*5 per cent of the population taken at that time. These fish measured between twenty and forty-three mm. in length. Fundulus grandis This killifish was the rarest of all the species found * One specimen taken in July, 1949? measured seventy-four mm. Another taken in April measured ninety-one mm. These two were the only examples of this species taken# Henidia bcryllina pen^nsulae The tide-water silverside was the most common of all the species. In July and August, there were 241 specimens taken, measuring between twenty-four and sixty-two mm. in standard length. These made up 42.2 per cent of the fish taken. The following April, the frequency of this species had almost doubled. The 493 specimens made up 75.2 per cent of the fish captured at this time. Broder mentioned that this subspecies never entered fresh water. However, the salinity of Tule Pond was always considerably below one part per thousand salt, and this species was very abundant. Gunter reported this species in. the Copano-Aransas area in salinities ranging from 0.0 to 34.9* V July and August 1949 April 1970 Totals Cy nrinodon va.rieyatus 40 36 76 Fundulus 1 1 2 Gambusia affinis affinis 109 94 203 Leponis macr ochirus 33 3 36 Lucania verms ta 18 23 41 Henidia beryIlina 241 493 734 Mo Ilie nisia lat1pinna 102 2 104 Mug11 cenhalas 27 4 31 571 656 1 5 227 Table III. Numbers of Fishes Taken at Tule Pond Other Vertebrates Reptiles: Several species of reptiles were taken in Tule Pond. Four Pseudemys elcaans (Troost’s Turtle) were taken in a fifty foot minnow seine, and as many as thirty-five turtle heads were seen at one time sticking out above the water. All of these turtles were observed in the extreme northwestern corner of the pond, which was the farthest point from the highway. Three Natrix rhomb if er a (diamond-back water snake) were taken, one of which was collected with the bag seine. Agkistrodon piscivorus (water moccasin) was found in June, 1948, along with Cnemidonhorus sexiinoatus (racerunner). A single Opheodrys aestivus. (rough green snake) was collected in August, 1949. It was found on a stem of grass at the water’s edge, A. W. Anderson reported seeing a small Alligator (alligator) here in April, 1950* Amphibians : Rana pipiens was very common. These frogs were found in large numbers at the water’s edge both at night and during the day. Two Hyla cinerea cinerea were collected in August. 1949? at night, and several others were heard calling. All were in the dense vegetation at the water’s edge. Birds: The shore and wading birds common to the area were abundant at Tule Pond. Ducks are reported to be numerous throughout the winter months* The most common bird was the cormorant, which was always present. Maxima Is t neither mammals nor their tracks were seen at Tale Pond, but they were probably present in the near vicinity. This is probably a watering place for both large and small mammals, the density of vegetation preventing them from leaving tracks* Invertebrates Of the larger aquatic invertebrates other than the insects, only crabs were found in Tule Pond* Crabs were taken with seines and with crab traps. The traps were the same as those used at Mine Mile Pond, Seining produced innumerable Callinectes snnidus (blue crab), but only two of the smaller Callinectes danae were taken. Traps baited with dead fish produced a catch of thirtynine crabs, all C. sapidus, during four trap-nights. This was an average of 9*75 crabs per trap-night. Broken down into sex groups. thirty-two of the C. sanidus were adult males, two were juvenile males, and five were juvenile females. The total absence of adult females C. sapidus was probably due to the fact that the adult females always go to water of a high salinity to produce offspring. The C. sagddus were measured here the same as at Mine Mile Pond. The average measurements for these adult crabs were respectively 125.8 mm. and 63.9 nm. The maximum measurements were 157 to 75 mm. and minimum was 110 to 57 mm. The crab population here was very high. V/hen walking around the edge of the pond, at least one crab was seen every five yards for the entire length of the shore line. All the adult crabs were covered with green algae. TULE POND INLET A small stream running into Tule Pond at the north end was seined on April 7$ 195$ 5 between two P.H. and three P.M. The stream had the appearance of a drainage ditch with bams of white sand piled high on both sides. The width varied from two to five feet. In many places it was choked with grassy vegetation, but there was a continuous flow of -water. Depth of the water varied from six to twenty-four inches, and the water was quite clear. The bottom was entirely of white sand. Vegetation on the bank consisted of a heavy live oak forest. The salinity here was found to be 0.4 parts per thousand. A total of 630 fish was collected from this stream by means of a six foot common sense minnow seine. The species collected were as follows: 1 • Gambasla affinis 2. Fundulus pulversus 3. Fundulus grandis 4. Cvprinodon variegatus J. lucania venusta 6. Hollienisia latiainna All of these fish were taken both in the vicinity of the mouth of the stream, and on the hauls farthest from the mouth. Cyprincdon variegatus was fairly common* The sixty-five specimens made up 10.3 per cent of the fish taken here. The standard length varied from twenty-one to forty mm. Fundulus grandis was not very common, with seven specimens making up approximately one per cent of the fish. Three Fundulus nulvereus. one male and two females, found hei’e made up O.p per cent of the total sample. Gambusia effinis was the dominant species* The 279 specimens collected made up 44.2 per cent of the total. The size range varied from eighteen to thirty-six mm. Lucania yemista constituted 4.1 per cent of the total, with twenty-six specimens collected* These fish ranged in size from twenty-five to thirty-nine mm. Hollienisia latinlnna v/as very close to G. aff,irds in frequency, with 236 specimens making up 37*6 per cent of the fish collected# In addition to these normal specimens, fourteen black spotted Lh latininna were taken. Six of these were males and eight were females# The black coloration ranged from a relatively few scattered spots on some of the females, to almost pure jet black in some of the males# The males were definitely the darker of the two sexes. The black K. latjpinna comprised five per cent of the total M. latipinna population. YELLOW POND —| Yellow Pond was so named because of the distinct yellow coloring of the water. This pond is located approximately 100 yards south of Nine Mile Pond on the Aransas Bay beach. A— It is approximately 100 yards long and twenty-five yards wide. The water was only thirty inches deep at the most, and thus it was subject, to considerable temperature variation. I-The oxygen content of the water, though measured inaccurately, was found to be 5*3 parts per thousand, much lower than nearby Nine Mile Pond# 7 Vegetation here was very dense, with Cypcrus so. and Paspalurn vaainatun being the dominant plants# The bottom of this shallow pond was made up of sand and mud# The fish population, though restricted in numbers of species, was apparently quite high# Two hauls of the twentyfive foot bag seine in. April, 1950$ yielded 952 specimens# These fish included the following four species: 1. Cyarlnodon varieratu3 2* Lucanla venusta 3. Hollienisia latipinno 4. Henidia bcrylljna /- Cyprinodon vcrieKatus was the dominant species with the 726 fish making up 76 per cent of the fish taken at this pond. The size range was eighteen to forty mm. Lucunia venus t a comprised thirteen per cent of the fish, with 123 specimens collected. The size range was between twenty-three and forty-seven mm. Mollienisia latininna constituted eight per cent of the total number, with seventy-five specimens. These measured from a minimum of twenty-two mm. to a maximum of thirty-five mm. —1 berylljna was the rarest species with eight specimens making up a little over one per cent of the total. The size range was twenty-five to fifty-one mm# lio attempt was made to discover the cause of the yellow color of the water. It may have been due to the presence of large amounts of organic matter. The effect of the water on the fish was obvious. All of the specimens had a slightly yellow tint except C. variegatus, which was of a bright golden hue. Perhaps it should be made clear that the yellow color of the water was not temporary, but at least semi-permanent. Seining this pond in October, 1949 for the University ci Texas Natural History Collection yielded this same golden colored Cyprinodon from the same yellow water. The yellow condition lasted six months at least# SHALLOW POND This pond, approximately twenty-five yards wide and seventy-five yards long, was located 200 yards northeast of Nine Mile Pond. It was very shallow (not over eighteen inches deep) and warm. The bottom consisted of mud and the water was very turbid# Salinity was found to be 5.3 parts per thousand# Tests for dissolved oxygen in the water indicated very little present. One haul of a twenty-five foot bag seine produced 256 Cambusia affinis and twenty tadpoles. No other vertebrates or invertebrates (other than insects) were found. The shallowness of the v/ater and the low oxygen content were probably responsible for only one species of fish being found# SUMMARY This study of brackish water ponds on Live Oak Peninsula, Aransas County, Texas was made during a period beginning in July, 1949, and ending in April, 1950# The ponds studied are compared on a basis of salinity alone as being the governing ecological factor. The two main ponds, Tule Pond of very low salinity and Nine Mile Pond of relatively high salinity may be compared in respect to their vegetation, fishes, other vertebrates, and invertebrates# —Tale Pond has thirteen species of plants, and Nine Mile Pond contains nine species of plants. Thus, a slightly greater h--'-' variety of plants is present in fresh water. / Three species common to both ponds are Bucopa munnlera, colony, and rlydrocptylG bonariensis. —f Eight species of fish are known from Tale Pond and thirteen from Nine Mlle Pond. This indicates a greater variety of species in the water of relatively high salinity. Six species of fishes are common to both Nine Mile Pond and Tale Pond. These are: 1< £Xn£ino6£n variegate 2. Fundulus grandis 3. Lucania yenusta 4• Menidia beryllina. 5* Mollienisle la ti pinna I-luEil cephalus L- Lepomis mperpehirus ? found in Tale Pond, is not present in any other pond. F. similis. A. bostoniensis, D. naculatus, G. bosci, and 0* beta were all present in Nine Mile Pond but not found elsewhere. Tule Pond Inlet, the stream running into Tale Pond has only six species of fish as compared with the eight in Tule Fond# Fundulus pulvereus and the black phase of HoHiendsla latininna , recorded here, were not found in Tale Pond* 4 Tale Pond in turn contained Lepomis mecrochirus, Mugil cephalus, and ilcnidia beryllina which were not found in Tula Pond Inlet. The break in the two populations was immediate, as if a physical barrier had been erected between the stream and the pond to prevent intermixing. Since the salinities were approximately the same (0.6 and 0.4 parts per thousand) it my be inferred that the differences in fish populations were due.to factors other than salt content of the water. — Yellow Pond, located just a hundred yards or so south of Nine Mile Pond, has only four species of fish, all of which are very common in Nine Mile Pond. The shallowness of the pond probably restrict the numbers of species found. The very shallow pond approximately 200 yards northcast of Nine Mile Pond has only Gembusia offinis, and these in very high numbers. A very low oxygon content in the water probably prevented other species from occupying this pond. Excluding the shallow pond containing the Gambusia, all the other ponds and streams studied have three species of fish in common. These are: CvorXasdon jjasiSSS. Lucania venusta Mollienisia la tin Inna These three species, all members of the killifish family, are apparently the most versatile of the fifteen species collected in this study. Salinity apparently plays no part in the size of the fish as approximately the same size range was found in all ponds* No comparison of the reptiles and amphibians can be made because it is an established fact that the various species of reptiles and amphibians that inhabit fresh water seldom enter salt water, and no evidence to the contrary was obtained in this study* A very good comparison can be made on the blue crab, fialllncctos at Tule Pond and at Nine Mile Pond. The crab population at Tula Pond was apparently much higher, but the crabs were smaller than at Nine Mile Pond. The average crab at Pule Pond measured 12J.8 mm. from tip to tip, while at Nine Milo Pond the average was 171*9 mm., or a difference of 46.1 mm. No shrimp were found in Tule Pond, a strange fact since P_alapomonot.es is so common in the area. Shrimp were very abundant in Hine Mile Pond, possibly being the dominant form of life there* LITERATURE CITED The vita has been removed from the digitized version of this document. Breder. Charles M* Jr*, Field Book of Marine Fishes of the Atlantic Coast. New York: G. P. Putnam f s Gons, 1948. Gunter. Gordon. Studies on Marine Fishes of Texas. Austin: The University of Texas, 194?. Jordan, David Star and Evermann, Barton Warren. The Fishes, of North and Middle America. (U.S. National Museum. Bul. No. 47). Washington: Government Printing Office, 1896. Small. J. K.. 19X3* Flora of the Southeastern United States. Published by author, New York*. Theroux, Eldridge, and Mallmann* Analysis of r; ater and Sev/age* 2nd Ed* Nev/ York and Londons McGraw-Hill Book Company, 1936* Toole, Marion* Utilizing Stock Tanks and. Earn Ponds for Fish. / «iBBsraMMRawM »3S®w KaßresnaEM’*'*”**'* mvaacsa aMaaauatMti Austin, Texas: Texas Gamo, Fish, and Oyster Commission. Bui* No* 24, 1946.