Changes in the Invertebrate Fauna, Apparently Attributable to Salinity Changes, in the Bays of Central Texas Author(S): Robert H

Changes in the Invertebrate Fauna, Apparently Attributable to Salinity Changes, in the Bays of Central Texas Author(s): Robert H. Parker Source: Journal of Paleontology, Vol. 29, No. 2 (Mar., 1955), pp. 193-211 Published by: SEPM Society for Sedimentary Geology Stable URL: http://www.jstor.org/stable/1300466 . Accessed: 18/06/2014 21:28

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This content downloaded from 132.174.255.3 on Wed, 18 Jun 2014 21:28:38 PM All use subject to JSTOR Terms and Conditions JOURNAL OF PALEONTOLOGY

A publication of THE SOCIETYOF ECONOMICPALEONTOLOGISTS AND MINERALOGISTSand THE PALEONTOLOGICALSOCIETY with the generous support and cooperation of THE AMERICAN ASSOCIATIONOF PETROLEUM GEOLOGISTSand THE GEOLOGICALSOCIETY OF AMERICA

VOLUME 29 MARCH, 1955 NUMBER 2

CHANGES IN THE INVERTEBRATE FAUNA, APPARENTL' ATTRIBUTABLE TO SALINITY CHANGES, IN THE BAYS OF CENTRAL TEXAS1 ROBERT H. PARKER Scripps Institution of Oceanography,La Jolla, California

ABSTRACT-Previousstudies on the invertebratefauna of the bays of central Texas have been undertakenduring periods of very low or highly variable salinity conditions. From 1948 to 1953 an extended drought with accompanyinglow river runoff caused salinities in these bays to increase to record highs, with little variation between maximum and minimum salinities during any particularmonth. Coincident with this extended high salinity period, the biotic communities within the bays changed considerably.Not only was there an invasion of many marineor open-Gulf species of invertebrates,but also a change was observed in the growth and appearance of the oyster reefs, one of the principalbiotic assemblages.Another probable result of increased salinities was the disappearanceof low-salinity mollusks which previous workers had found to be extremely abundant during the periods of low salinity. This extended series of hydrographicobservations should be useful to the paleoecologist in interpretingenvironmental changes in megafossil assemblages. Obser- vations of this nature should prove useful in interpretingsedimentary facies, since many of the species involved occur as fossils at least as far back as the Pliocene. If the normal euryhaline fossil assemblagessuddenly produce large numbers of high- salinity organisms such as sea urchins, corals and open-Gulf mollusks, one could assume that there had been drought conditions,with extended high salinities. These conditions can also be recognizedby abrupt changes in shell structure of the common oyster, Crassostreavirginica (Gmelin), as well as the absence of the known low- salinity mollusks.

INTRODUCTION bays and their fauna. As a result of the published work on this 1931; NUMBER major papers have been pub- region (Galtsoff, A of Gunter, 1945, 1950a; Collier and lished on the biological and hydro- Hedgpeth, 1950; Ladd, Puffer and graphic aspects of the shallow bays of the 1951; Emerson, central Texas coast. Few of these studies 1953; and Hedgpeth, 1953), the relation- have coincided with the recent ships of the faunal composition of the bays drought to the have been established conditions, and little information is avail- salinity regime able on the effects of these in general terms. In 1950-53 the author droughts upon made an of the in the 1 ecological study bays Contribution from Scripps Institution of Rockport area (Fig. 1); this was begun Oceanography,new ser., No. 754. This investigation was supportedby a grant from the American as part of the regular oyster survey for Petroleum Institute, Project 51. the Texas Game and Fish Commission 193

This content downloaded from 132.174.255.3 on Wed, 18 Jun 2014 21:28:38 PM All use subject to JSTOR Terms and Conditions 97*10' 28*20' 9700' 96050' \O cP ARKANSAS OKLAHOMA /GUADALPE RIVER .RIVER ROCKPORTAREA, TEXAS TEXAS

I HYNESX \i

0 AN0 cOINT 0C PUXIUPPER ., 0 OF MEXICO •SYGFGULF MEXICODWL n

o. .. O FULToNMLSNEER-,UPPER ARANSAS

ROCKPORT h3 o#ou 3?( 92-4"EEF x 9-"" "tl b

MILEs .. .. .STATUTE

" 00' """ 9 3 O A ...... 96* 503 28500' 96 30'

FIG. 1-Location map.

This content downloaded from 132.174.255.3 on Wed, 18 Jun 2014 21:28:38 PM All use subject to JSTOR Terms and Conditions SALINITY A FFECTS ON TEXAS BA Y FA UNAS 195 and continued as part of the field work of generous assistance of the staff of the Project 51, American Petroleum Institute. Marine Laboratory, Rockport, Texas, and It was observed that the distribution of cer- the staff of the American Petroleum Insti- tain marine invertebrates, especially mol- tute Project 51 at Scripps Institution of lusks and echinoderms, differed from that Oceanography at La Jolla, California. For indicated by previous major studies, which invaluable assistance and cooiperation, the were undertaken during times of compara- author is particularly grateful to Drs. Joel tively heavy rainfall. During the author's W. Hedgpeth, Francis P. Shepard, Carl L. observations, salinities in the bays were Hubbs, and Robert S. Arthur of Scripps In- much higher than during years of higher stitution; Dr. Gordon Gunter and Mr. rainfall and greater stream discharge. Martin W. Burkenroad of the Institute of Salinity data for the years 1948-52 were Marine Science, University of Texas; determined by titration by the staff of the Messrs. F. M. Dougherty and Byron B. Marine Laboratory of the Texas Game and Baker of the U. S. Navy Hydrographic Fish Commission and by the staff of the Office, Suitland, Maryland; Messrs. E. D. Department of Oceanography, Texas A. & McRae and Dewey W. Miles, formerly of M. College for the American Petroleum the Rockport Marine Laboratory; and Institute Project 51. For the period from Messrs. Ernest Simmons, Robert Hof- March, 1952, to September, 1953, hydrom- stettor and Howard Lee of the present staff eter readings from the U. S. Coast and of the Marine Laboratory. Sincere apprecia- Geodetic Survey tide station at Rockport, tion is extended to Mr. Cecil Reid, Chief Texas, were used. The manner in which Marine Biologist of the Texas Game and salinity values were obtained in the pub- Fish Commission, and to Mr. J. L. Baugh- lished data is given in the references cited in man, formerly of the Marine Laboratory, the captions for the various graphs. now of the Copano Research Foundation, River discharge data for the years 1936 for the use of their facilities and for data on to 1951 were obtained from the Surface Wa- file at the Marine Laboratory. The author ter Supply Papers of the U. S. Geological also extends grateful appreciation to Mr. Survey. For the period from 1951 to Septem- James Moriarty and Miss Majorie Browne ber, 1953, data were supplied by Mr. S. D. of Scripps Institution for the preparation of Breeding of the Austin, Texas, office of the the charts and graphs. Surface Water Branch of the U. S. Geologi- I. cal Survey. Rainfall data for Victoria, Texas, SALINITY, RIVER DISCHARGE AND RAINFALL RECORDS were obtained from the Local Climatological Summary of Victoria, published by the U. S. A. Aransas Bay.-According to Collier Weather Bureau. and Hedgpeth (1950), the mean annual Faunal collections in the area were ob- salinity of Aransas Bay for a "normal year" tained by the use of shell and oyster dredges, is approximately 19 to 200/oo. This is further oyster tongs, otter and beam trawls, Navy emphasized in a mimeographed report by Electronics Laboratory snapper-type grab, Williams and Whitehouse (1952), which and orange-peel grab, and by beach collect- summarizes the previously published data ing. Over 500 stations were occupied as part and discusses the chlorinity data of the of this study, and several stations in Aran- 1951-52 field seasons of A.P.I. Project 51. sas Bay were occupied weekly. The echino- Although most of the data published before derms and corals were identified by Dr. J. 1947 have been reviewed by Williams and Wyatt Durham and Mr. Elton Puffer of the Whitehouse (1952) and Whitehouse and Museum of Paleontology, University of Cal- Williams (1953), these summaries do not ifornia, Berkeley, and the majority of the include salinity determinations made during mollusks by Dr. Thomas E. Pulley, Univer- the critical years of 1948, 1949, 1950, early sity of Houston, Texas, and Messrs. Wil- 1951, 1952, and 1953. Hedgpeth (1953), liam K. Emerson and Elton Puffer of the however, cites salinity averages by months Museum of Paleontology, University of Cal- from 1948 through 1951, which were ob- ifornia, Berkeley. tained from the United States Coast and This work was made possible by the Geodetic Survey tide station at the Marine

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Laboratory of Rockport, Texas. Four ever, caused a considerable drop in salin- months' data are missing from these years, ity. and the accuracy of readings at the tide sta- There has been a partial elimination of tion is somewhat in doubt. After Septem- the gradients in salinity facies in Aransas ber, 1947, the mean monthly salinities re- Bay as determined by Ladd (1951). The mained above 200/oo, and they remained differences in salinity between Lydia Ann above 30/,,o from June, 1950, until Septem- Channel and lower Aransas Bay and those of ber, 1952, attaining the very high value of upper Aransas Bay near Carlos Bay and in 420/oo in August, 1951 (Fig. 2). A record 14- the Copano Strait were 5.60/,,oo in November, inch rainfall in the Rockport area in Septem- 1951, and 2.20/oo in January, 1952. During ber, 1951, had no great effect on the average Ladd's investigation, the difference in salin- salinities in Aransas Bay. Somewhat in- ity between opposite ends of Aransas Bay creased rainfall in the Aransas Bay area and was approximately 120/oo. in the San Antonio-Guadalupe River drain- Salinities in Aransas Bay have consist- age basin in late 1952 and early 1953, how- ently risen above 200/oo during the summer

w 84

TOTAL MONTHLY PRECIPITATIONAT VICTORIA,TEXAS IN SAN ANTONIO-GUADALUPEDRAINAGE BASIN

220,000- 676.363 269 12 7 2 - - --1 - 27137 -

i' 24.42 S4180,000 4.54 ......

40,000

"0 1 193 7 It13 1 1939 940I9o43 1141I 194t11 Ie4s 1 1944 1 9451 ,41 1948I*4* l Is I 9! s TOTAL MONTHLYSTREAM DISCHARGE.SAN ANTONIORIVER AT GOLIADAND GUADALUPERIVER AT VICTORIA,TEXAS A -AVERAGE 2 _ _ IVw - - m-- In _'- l '-i I-

0'192V A 7 19393 ! 937t 9os 9o3 1 9 1941 1942 1943 1944 194 1944 1947 9481 9491 9 59 1 l YEARS 8YBY MONTHS A. MONTHLYMAXIMUM-MINIMUM WATER TEMPERATURES, ARANSAS BAY, TEXAS B. MONTHLYMAXIMUM-MINIMUM SALINITIES, ARANSAS BAY, TEXAS

FIG. 2-Comparison of water temperatures and salinities of Aransas Bay, Texas, with rainfall and river discharge in the San Antonio-Guadaluperiver system. Salinities and water temperature data from 1922-23 (Collierand Hedgpeth, 1950), from 1926-27 (Galtsoff, 1931), and from 1936-46 (Col- lier and Hedgpeth, 1950).

This content downloaded from 132.174.255.3 on Wed, 18 Jun 2014 21:28:38 PM All use subject to JSTOR Terms and Conditions SALINITY AFFECTS ON TEXAS BA Y FA UNAS 197 months in the past, but the change in August, 1951, was a salinity lower than salinity can best be demonstrated in the 32.20/oo observed in Copano Bay. The ranges between maximum and minimum highest observed salinity was 400/oo, and the values during each month. Between 1926 mean for that period was about 360/oo (Fig. and 1947, the salinity has ranged from 10 3). The maximum-minimum range is much to 300/oo during most of the months, even in narrower and the rise more spectacular for the summer. After 1947 the difference be- Copano Bay than in Aransas Bay, as can be tween maximum and minimum became observed by comparing figures 2 and 3. very small at all seasons (Fig. 2), although Higher salinities are to be expected in there were very few readings for some shallower Copano Bay in relation to periods months. During the months of moderately of reduced rainfall and high evaporation high rainfall in the years 1936, 1941, 1942, over the Copano watershed, as pointed out 1946, and 1947, salinity conditions in by Collier and Hedgpeth (1950). River run- Aransas Bay were highly variable through- off from Mission River is so slight during out the year and appear to be somewhat dry years (as compared to the San Antonio- more concentrated in the low range of Guadalupe rivers), that practically no salinities from 5 to 250/oo (Fig. 2). However, freshening of this bay can occur. Evapora- during years of drought, in 1948 to 1952, in tion, then, can have a very telling effect up- the Rockport Bays, salinities were far less on this shallow enclosed bay. variable and were more concentrated in the D. Redfish Bay.-Redfish Bay, on the west upper range (25 to 400/oo). side of Aransas Bay and behind Harbor Is- B. San Antonio Bay.-San Antonio Bay land, is nearly landlocked, extremely shal- has also shown a gradual increase in salinity low, and close to the higher salinity waters since 1950, in spite of heavy discharges from of Aransas Pass; therefore, it is usually sub- the Guadalupe River in June, September ject to rather high salinities in the summer. and October, 1951 (Fig. 2). Galtsoff (1931) In the absence of salinity data for earlier states that in 1926 salinity values for upper years. Little can be said concerning the San Antonio Bay were in the neighborhood changes in the bay except for the period of 4 to 100/oo and for lower San Antonio Bay since 1947. According to salinity values ob- from 10to 170/oo. Baker (1950) found salinity tained by Hedgpeth (unpublished data), ranges from 13.1 to 24.40/oo in lower San Baker (1950), and the author, salinities in Antonio Bay in 1950. In 1951, the author Redfish Bay ranged from 39.80/oo at the peak found salinity values ranging from 20.3 to of the dry season in 1950 to 21.70/oo in the 32.10/oo in lower San Antonio Bay and Mes- winter months of 1949 and 1950. From Octo- quite Bay, whereas the A.P.I. field party ber, 1947, to May, 1948, February to April, from Scripps Institution obtained salinity 1949, and October, 1949, to June, 1950, sa- values of from 23.90 in upper San Antonio linities remained below 300/oo. After June, Bay to 41.420/oo in lower San Antonio Bay 1950, salinities rose above 30 and remained in July and August, 1951. These are the above 310/o, throughout 1950 and 1951. highest salinities to be recorded from this E. Mesquite Bay.-The maximum and usually low salinity bay. Williams and minimum salinities for Mesquite Bay are Whitehouse (op. cit.) state that salinities in shown on figure 4. Although data are scarce lower San Antonio Bay still ranged from during so-called wet years, it can be seen 27.39 to 31.160/oo (converted from chlorin- that in 1926, 1927, 1936, and 1937 salinities ities) in January and February, 1952, al- ranged between 4 and 190/oo, and from 1947 though upper San Antonio Bay salinity to 1950 from 14 to 280/oo. During these years values were much lower. Salinities in late salinities were still essentially those of a low- 1953 were still well above the "normal" of to medium-salinity bay. However, in 1950 10 to 170/oo as suggested for San Antonio Bay and 1951 salinities were not obtained below by Ladd (1951). 220/oo, and at one time they ranged to above C. Copano Bay.-In the spring and sum- 400/oo. A record of salinity values obtained by mer of 1951, salinities were generally higher Mr. Ernest Simmons of the Marine Labora- in Copano Bay than in Aransas Bay. At no tory, taken approximately every two hours time during the period from July, 1950, to in the center of Cedar Bayou (Table 1),

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0 w so a. 60

z 20

1936 1937 1938 1939 1940 194194942 1943 1944 1945 946 1947 1948 1949 1950 191 192 1953 TOTALMONTHLY STREAM DISCHARGE, MISSION RIVER AT REFUGIO, TEXAS

40 A

40 B

1936 1937 ,938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 194911950 1951 1952 1953

A. MONTHLYMAXIMUM- MINIMUM WATER TEMPERATURES, COPANO BAY, TEXAS B. MONTHLYMAXIMUM-MINIMUM SALINITIES, COPANO BAY, TEXAS

FIG. 3--Comparison of salinities, water temperatures of Copano Bay, and Mission River stream discharge.Salinity and water temperaturedata for 1936 to 1947 obtained from Collier and Hedg- peth (1950).

shows very little change (not more than values were attributed to fresh water runoff in over a 1.6'/oo) salinity three day period. and occurred simultaneously with the very Since this period covered at least two com- low salinities in the bays. Gunter (1945) plete astronomical tide cycles, it would ap- states that the mean salinity of this coastal that tides pear apparently do not bring water is about 320/oo. Salinity observations enough Gulf water into Mesquite Bay to for the spring and summer of 1951 close to raise the salinity noticeably. From the above shore in the vicinity of Port Aransas indi- data it would that appear Mesquite Bay cated a range of from 36.19 to 39.900/o,,, 4 to is more affected river by runoff and evapora- 6 parts higher than during the "wet" years tion than by influx of Gulf water. of 1935 to 1941. F. The Gulf of Mexico.-The salinities of G. General Considerations of River Dis- the coastal fringe of the Gulf of Mexico in charge, Rainfall and Salinity.-In order to the of vicinity Port Aransas and Cedar determine whether droughts are responsible have Bayou risen to a slight degree re- for the increased salinities in the Rockport cently, according to the few data available area, all available discharge data for the (Fig. 4). Phleger (1951) notes that surface rivers which empty into these bays, as well salinities taken off Corpus Christi, near as representative rainfall data from the Aransas Pass, by the Atlantis in 1935, drainage areas, have been plotted with the from ranged about 31 to 33/oo,,. These low associated salinites and water temperatures.

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TABLE 1.-RECORD OF SALINITIES TAKEN AT responding drop in salinities in the bays into CEDAR BAYOU FROM 11:45 APRIL 18, TO 07:00 which for the same SUPPLIEDBY MR. ERNEST they empty years (Figs. APRIL21, 1950; 2 and to these the ef- SIMMONS, T. G. & F. C. 3). According graphs fect of increased runoff is felt in the bays within less than a month, and likewise, as Date Hour Salinity 0/oo soon as the runoff is reduced, salinity values 4/18/50 1145 22.7 rise rather rapidly to the values occurring 1350 22.6 rainfall 1558 22.7 prior to the runoff. The total by 1745 22.9 months in the drainage areas of the San 2000 22.9 Antonio-Guadalupe rivers is also reflected 4/19/50 0730 22.6 in the total monthly discharge figures of 0900 22.1 these rivers 1355 22.5 (Fig. 2). 1455 22.4 In order to demonstrate more clearly the 1715 22.9 long term changes in salinity in the Texas 2000 22.9 bays, a graph was prepared showing the 4/20/50 0730 22.9 total river for the San 0945 22.8 yearly discharge 1154 22.4 Antonio-Guadalupe rivers as compared with 1350 22.4 the yearly average salinities in Aransas Bay 1600 22.3 (Fig. 5). According to this graph those 1755 22.2 from 1934 to 1948 2020 22.3 periods approximately 2200 22.9 show correspondingly high runoff and low 2/21/50 0700 23.7 salinity. Starting in 1947, river discharge became less and less (associated with decreased When there are extended periods of heavy rainfall), and the average yearly salinities runoff from the San Antonio-Guadalupe and increased from 20 to 350/oo. Prior to 1947, Mission rivers, as during 1936, 1938, 1941, average yearly salinities ranged from 15 to 1942, 1946, and early 1947, there is a cor- 200/oo. This graph has been expanded to in-

* 40

30 20 10 0 NEARARANSAS PASS GULFOFIMEXICO,, I

40 e 30 S20 z -i 4 10

0 19261 19271 19361 19371 19381 9411 194e1 1947j 1948[1 949 1950 1951 1952 MESOUITEBAY, TEXAS

FIG. 4--Comparison of salinity data from Mesquite Bay and the Gulf of Mexico. Data for 1926- 1927 from Galtsoff (1931), for 1936-1947 from Collier and Hedgpeth (1950).

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14 70

60 o 0 C12 50

a. 40 w2 6

o 30

o o 20 0 4

0 10

0 1936 1938 1940 1942 1944 1946 1948 1950 1952 1954

TOTALYEARLY DISCHARGE, GUADALUPE RIVER AT VICTORIA, TEXAS AVERAGEYEARLY SALINITY, ARANSAS BAY, TEXAS

M.A

FIG. 5-Comparison of total yearly dischargeof Guadalupe River with average yearly salinity of Aransas Bay, Texas. clude monthly mean salinities and monthly served during 1948 to 1953. The composition mean river discharge (Fig. 6) for Aransas of the biotic communities has changed con- Bay in order to demonstrate the relation- siderably during this high salinity period. ships between salinity and river discharge One organism which appeared to be consid- on a monthly basis. Again it may be ob- erably affected by the increased salinity was served that with monthly increases in river the oyster, Crassostrea virginica (Gmelin), discharge, salinity decreases are reflected in which is the principal component of the Aransas Bay within a month. The rise in extensive shell reefs in this area. The salinity salinities from February, 1948, through 1953 increase was briefly noted by Puffer and is depicted somewhat more spectacularly Emerson (1953) and was cited as a possible in the plots of the mean salinities than in explanation for reduced production of maximum and minimum salinity graphs, al- oysters in the Texas bays. This mollusk has though the significant narrow range of been the most studied organism in the local salinity during the drought years is not ap- bays, receiving considerable attention from parent. Galtsoff (1931, 1942), Gunter (1950a), Baughman and Baker Puffer and II. BIOLOGICAL CONDITIONS (1950), Emerson (1953), and various investigators A. The Change in Salinity in Relation to for the Texas Game and Fish Commission Oyster Reef Conditions.-Previous marine bi- throughout the past 50 years. It is generally ological studies have been made in the cen- considered that this oyster is best adapted tral Texas coastal area during periods of to an estuarine environment, with a salinity much lower salinities than have been ob- of 12 to 19o/oo (Ladd, 1951 and Gunter,

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1953), and does not form extensive reefs A change in the growth-rate and meat in areas of high salinity. However, Kor- condition of the oyster was noted during the ringa (1952) states that experimental evi- period of increased salinity (1950-1952). dence conflicts with field observations, and According to Byron B. Baker (personal no definite conclusion can be drawn as to communication) oysters from 1948 to the exact salinity preferences. Amemiya (1926) fall of 1950, were thin, flabby and tasteless, determined in the laboratory the lower and even when they were not spawning. Glyco- upper salinity limits of the developmental gen-content tests by the Texas A. & M. stages of the American oyster, C. virginica. Research Foundation (unpublished com- Amemiya found that below 150/o. and above munication in the files of the Texas Game 30'/o,, abnormal segmentation of the oyster and Fish Commission), showed a very low larvae took place, and very few shell-bearing glycogen content for oysters in Aransas Bay larvae were formed. Such developmental ab- during the period of 1948 to 1950. For normalities could very well limit populations several years, when the salinities were gen- in waters of either very low or very high erally below 250/oo, no appreciable shell salinity. growth was observed in oysters larger than

bir0 bi hI 0 asahi 9 Nt

13 14 19 1'.3 . l0e 14 1 194t14 1* I?1 i 414 io [ l weLt Iia MONTHLYMEAN DISCHARGE,GUADALUPE RIVER AT VICTORIA,TEXAS

o40

0 e193* 1935 195 1 941 I s4t *46 m194r 1 1949* 1 so950 ee51 I e e1953 MONTHLYMEAN SALINITIES ARANSAS BAY, TEXAS

FIG.6--Comparison of monthly mean salinities of Aransas Bay, Texas, with monthly mean river dischargeof Guadalupe River, Texas.

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two or three inches. After the salinities had such rapid and long growth had previously risen above 30o/o, a definite change was ob- never been observed in so short a period. served in most of the oysters. The rate of Oyster glycogen-content increased fairly new shell growth increased in old oysters rapidly, according to tests performed by (those with very thick but stubby valves). the author. It is generally considered that In less than two months, many old oysters oysters are at their best in Aransas Bay dur- produced new extensions of the valves of ing the winter months, as intense spawning two or three centimeters in length, and by activity saps their vitality whenever water March, 1951, most oysters observed had temperatures remain above 200C for any long, highly-colored, crenulated valves of length of time (Gunter, 1942). During the new, sharp growth. Many oyster men and spring and summer of 1951, most of the biologists native to this locality stated that oysters sampled were of exceptional fatness

35 30 w 25 20 : 15 10 5 MAXIMUM-MINIMUMWATER TEMP. OYSTERI I I POORTO FAIR GOOD UALITY QUALITYI : 45 40

- 35 30 S25 z 20

10 5 MAXIMUM-MINIMUM -SALINITY 1946 1947 1948 1949 1950 I 1951

J. M.

FIG. 7-Comparison oyster quality (determinedby glycogen analysis and other oyster quality tests) with water temperatureand salinities of Copano Bay, Texas.

This content downloaded from 132.174.255.3 on Wed, 18 Jun 2014 21:28:38 PM All use subject to JSTOR Terms and Conditions SALINITY AFFECTS ON TEXAS BA Y FA UNAS 203 and quality, even though in spawning condi- and rare L. alternata (Say). Other echino- tion (Fig. 7). A change in oyster appearance derms collected year-round were many sand and quality was again observed during dollars, Mellita quinquesperforata (Leske), January through March, 1952. Instead of two species of sea urchins, Arbacia punc- rapid new growth, as in the previous year, tulata (Lamarck) and Lytechinus variegatus most oysters had little new growth, al- (Leske), and five species of ophiurans, though they were of continued high quality. Ophiolepis elegans Liitken, Hemipholis Oysters were reported to be dying in large elongata Say, Amphiodia limbata (Grube), numbers in Copano Bay during 1952 (R. Ophioderma sp., and Ophiothrix sp. Hedg- Hoffstettor, personal communication), al- peth (Whitten, Rosene and Hedgpeth, 1950) though in 1951 Copano Bay oysters were reports two brittle stars, Hemipholis elongata larger than previously observed for several and Ophiactis sp., one sand starfish, Astro- years. It might be mentioned that with the pecten antillensis Liitken, and the sea declining salinities of the latter part of 1953, urchins, Arbacia punctulata and Lytechinus oyster production is apparently improving variegatus, from the vicinity of Port Aransas in Aransas Bay. and Aransas Pass in the open Gulf. In the An indication of a change in the faunal present collections, except for the brittle composition of the oyster reefs in central stars which have been found over most of Texas bays is the presence of large numbers the sand-slit-clay bottoms of Aransas Bay, of the small oyster, Ostrea equestris Born. parts of Copano, Mesquite and lower San This oyster is normally found in waters of Antonio Bays, most of the echinoderms high salinity, and seldom occurs abundantly have been collected from the northeast end in any of the bays, although it has always of Lydia Ann Channel, near Mud Island, been present in Lydia Ann Channel and and in the southeastern section of Aransas Aransas Pass (J. W. Hedgpeth, personal Bay. Although the Mud Island area has al- communication). Examination of oyster ways presented a somewhat different faunal spat from Copano Bay in March, 1952, re- appearance from the rest of Aransas Bay, vealed that almost half of the small oysters the echinoderms mentioned above have not of from an inch to an inch and a half in been noted in previous publications (which, diameter were adults of Ostrea equestris. however, did not attempt to catalogue the Samples of spat obtained from Long Reef, fauna of Aransas Bay) or at least have not Tin Can Reef, and other small reefs in been observed as year-round residents. Aransas Bay were composed of over 50 Large numbers of the sea pansy or sea per cent 0. equestris. This oyster never liver, Renilla miilleri Kblliker, and an in- grows very large; but it could supply a shell creasing number of colonies of whip coral, base for the common oyster to set when the Leptogorgia setacea (Pallas), have also been bays return to lower salinity. Large num- taken during all seasons around Mud Is- bers of 0. equestris in old C. virginica reefs land, and in the Intracoastal Waterway, buried in Recent and possibly Pleistocene well up into Aransas Bay as far as Rockport. sediments probably indicate high salinity It was observed that strands of whip coral conditions at the time of deposition. in the center of Aransas Bay were smaller B. Apparent Faunal Changes in the than those living closer to Gulf waters. Aransas Bay System.-During the period of Those obtained directly off Rockport were extended high salinity, many organisms from two to three inches tall, whereas those were collected in Aransas Bay which had found near Mud Island and in nearshore never been reported from this area before, Gulf waters were two to three feet long. The including some previously considered char- author also found living star coral, Astrangia acteristic of the Gulf waters. The most unu- astreiformis Milne Edwards and Haime, in sual of the "marine invasions" into the Aransas Bay as far northeast as the old bays was that by various echinoderms usu- shipyard at Rockport. Many lumps of dead ally confined to waters of higher salinity, coral have also been found in Lydia Ann and rare or not hitherto reported in Aransas Channel and around Mud Island. Ladd Bay proper. These include large numbers of (1951) lists this coral as abundant in lower starfish, abundant Luidia clathrata (Say) Aransas Bay, near the passes into Redfish

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Bay and Lydia Ann Channel, and his ob- 1950) lists as probably Tethys floridensis servations have been confirmed by Hedgpeth Pilsbry, was also noted in the spring of 1951. (personal communication). A map, figure 8, In 1951, hundreds of these large (4 to 10 shows the farthest advance of the open Gulf inches long) animals were observed in all organisms. Neither Gunter, Hedgpeth, Reed parts of Aransas Bay and Corpus Christi (1941), nor Ladd lists Renilla or Leptogorgia Bay. Whether this influx of sea hares can be as inhabitants of Aransas Bay, or even associated with the increase in salinity, or is Lydia Ann Channel which is usually more part of a resurgent population, is a matter saline than the bays. Hedgpeth (personal for speculation. Hedgpeth (1950) and Reed communication) suggests that Renilla may (1941) state that they are usually found on have always been present in small numbers beaches after storms, but are occasionally in Lydia Ann Channel. taken in the bays. A wide occurrence of tectibranchs, which The distribution of two arthropods, Hedgpeth (Whitten, Rosene, and Hedgpeth, Penaeus setiferus (Linn6) and Callinectes

ROCKPORTAREA, TEXAS KNOWN DISTRIBUTIONOF OPEN GULF ORGANISMS IN THE BAYS ( 1950- 1953)

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This content downloaded from 132.174.255.3 on Wed, 18 Jun 2014 21:28:38 PM All use subject to JSTOR Terms and Conditions SALINITY AFFECTS ON TEXAS BA Y FA UNAS 205 danae Smith, also appears to have changed (1952), however, made collections of C. during this high-salinity period, and it may danae during the early portions of this pe- or may not have been associated with the riod of increased salinity and observed that salinity change. Of the two, P. setiferus,the far greater numbers of this crab were pres- common commerical or white shrimp, has ent in the bays than previously, and that shown the greater change. Prior to 1949, they were present there throughout the when the salinity was low, this shrimp year. Personal observations during 1950, formed the major portion of the commerical 1951, and 1952 also showed an increase in net hauls of shrimp in the Texas bays in the numbers of the Gulf Crabs in the bays, al- fall. According to Hildebrand and Gunter though actual counts were not made from (1953), however,production of white shrimp month to month. Hauls taken in March, in Texas fell from 2 to 7 millionpounds from 1952, contained many more Gulf crabs than 1949 to 1951. An analysis of otter-trawl blue crabs, and at times the Gulf crabs con- catches taken by the author during the fall stituted a major portion of the total trawl of 1951 and spring of 1952 showed that only catch. one to five per cent of the total shrimp con- Considered somewhat unusual for these sisted of P. setiferus,while juveniles of P. Texas bays was the occurrence of 23 species aztecus Ives and P. duorarumBurkenroad of living mollusks which usually occur in comprised the bulk of the shrimp catch. waters of high or oceanic salinity and have Gunter (1950) discussed the seasonal abun- never been reported living in these bays dance of all three species of shrimp in detail, before. Because of the large number of and emphasized that P. setiferus occurs in species of mollusks involved, and the fact vast abundance and supports the com- that many other investigators have dealt mericalcatch in the fall. Burkenroad(1951) with their distribution here in the past, a states that in the Aransas Bay area the table has been prepared comparing the dis- sharp decline in the numbersof young white tribution of the mollusks during the times shrimp is probably associated with the re- of high salinity and during the times of low cent high salinities. Hildebrandand Gunter salinity (Table 2). The majority of collec- (1953) indicate that there is a high correla- tions of mollusks from the Texas bays have tion between the productionof white shrimp been made during times of reduced salin- and the increase or decrease of rainfall. ity; therefore, the species of mollusks said Since, as indicated in the discussion of the to be indicative of the bays are quite differ- physical-chemicalfactors, there is a rather ent from those which are now abundant, al- high degree of association between rainfall, though most of the species found previously runoff and salinity in the Texas bays, it is are still present. However, Rangia cuneata reasonableto assume that salinity has been (Gray), a low salinity mollusk, has virtually at least partly responsible for the decrease disappeared. At the time his collections were in shrimp. Hildebrandand Gunterstate that made in upper San Antonio Bay (1940), the correlation may be either with salinity when the salinities ranged from 4 to 90/oo, per se or with some unknown factor gov- Ladd collected large numbers of Rangia, of erned by salinity. which most were living. Burkenroad (per- The abundanceof Callinectesdanae, which sonal communication) also states that he in the summer of 1951 and spring of 1952 has found large populations of Rangia living was far more numerous than in the previous in this locality during times of very reduced year, may also be asssociated with high salinity. During the summer of 1951 and salinity. This crab is commonly known as spring of 1952, when salinities were gener- the Gulf crab, and is smaller than the com- ally much higher (11 to 200/oo), no living mon edible blue crab, Callenictes sapidus specimens of Rangia were taken in San Rathbun. Gunter (1950) compares catches Antonio Bay although extensive collections of the Gulf crab from Aransas Bay and the were made throughout all of the bay. Gulf of Mexico in 1941 and 1942, and shows Associated with Rangia is the minute gastro- very few individuals present in Aransas Bay, pod, Littoridinasphinctostoma Abbott and as compared to the large numbers in the Ladd, which Ladd found alive only in waters open Gulf at the same time. Daugherty of very low salinity. In 1940 it was said to be

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This content downloaded from 132.174.255.3 on Wed, 18 Jun 2014 21:28:38 PM All use subject to JSTOR Terms and Conditions Marginella apicina D X Mangelia cerinella D X L Terebracinerea X X D A D D Terebradislocata D X X Terebraprotexta D D D Actaeon punctostriatus X D Acteocina canaliculata D A X D A Bulla occidentalis D D X A X D L Haminoea elegans A X D Melampus coffeus A X X D D Siphonaria pectinata A A A SCAPHOPODA Dentalium texasianum D D A X X D D A PELECYPODA Nuculana acuta D A X A D A Nuculana eborea A X X A Anadara ovalis D D A X A A X D A D A Anadara chemnitzi X D Anadara braziliana A X X D X D D Anadara secticostata X D Aandara transversa D D X A A X D A D A Arca umbonata D X D D Noetia ponderosa D X X A D X D D A D Brachidontesrecurvus A A X X A A A X Brachidontesexustus A D X A A Lithophaga bisulcata A Volsella demissa granosissima D A Modiolus tulipus X X A X D D Atrina rigida D A X X A X D D A Atrina serrata D D X X X D D Aequipectengibbus amplicostatus A X X X D A X D A D A Aequipecten gibbus concentricus D X X D D D Anomia simplex D A X D A A A X D A D A Ostrea equestris A A A X D A D A Crassostreavirginica A A X X X D A A A A X D A D A Crassinella martinicensis A D A D D A Carditafloridana D D D D D X X D D D D Polymesoda caroliniana A X D D Polymesodafloridana A D D X D X Diplodonta punctata L Diplodonta semiaspera D Anodontia schrammi X D D D D Anodontia alba D X D D D L Lucina amiantus D X A L Lucina crenella D X D D X D D Lucina floridana D X D D Lucina pectinata D A A X X D D D Dinocardium robustum D A X X D D X D D D D Laevicardiumlaevigatum D D X D D D D Laevicardiummortoni A X A X X A A Trachycardiummuricatum D A X X A A X X D A D A Anomalocardia cuneimeris D A X D A D A Chione cancellata D D X A A X X D A D A Chione intapurpurea X D D

* Collection oily made on living forms. 1Singley, J. A. 1892. Texas mollusca. 4th Ann. Rept. Geol. Surv. Tex., 297-343. 2 Mitchell, J. D. 1894. List of Texas mollusca. Victoria, Texas, Times Steam Print: 22. 3 Cross, J. C. and Hal B. Parks, 1939. A check list of Texas marine mollusca. Tech. Bull. of Stephen F. Austin, State Teachers College, Nacogdoches, Tex., 1: Tech ne. 2. 4 Reed, Clyde T. 1941. Marine life in Texas waters. Texas Acad. Publ. in Nat. Hist. Non-tech. series, xii, 88 pp. 5 Ladd, Harry S. 1951. Brackish water and marine assemblages of the Texas coast with special reference to mollusks. Publ. Inst. of Mar. Sci., 2(1): 125-164. 6 Gunter, Gordon 1950. Seasonal population changes and distributions as related to salinity of certain invertebrates of the Texas coast... Publ. Inst. Mar. Sci., 1(2): 7-51. SWhitten, H. L., H. F. Rosene, and Joel W. Hedgpeth. 1952. Invertebrate fauna of the Texas coast jetties: a preliminary survey. Publ. Inst. Mar. Sci., 1(2): 53-87. 8 Pulley, Thomas E. 1952. An illustrated check li;t of the marine mollusks of Texas. Tex. J. of Sci., 4: 167-199. 9 Data compiled by Elton Puffer and William K. Emerson for the American Petroleum Inst., Project 51, during Jul.-Aug. 1951 and Feb., 1952. 10Data compiled by Robert H. Parker and Howard K. Lee for the Texas Game and Fish Commission and A.P.I. Project 51 during the years 1950 through 1953. (Continued on next page)

This content downloaded from 132.174.255.3 on Wed, 18 Jun 2014 21:28:38 PM All use subject to JSTOR Terms and Conditions TABLE 2.-Continued A-Alive. D-Dead. X-Reported, condition not stated. L-Alive, not reported before.

Collector

Cross & Emerson & Parker & Singley, Mitchell, Parks Reed, Ladd, Gunter, Hedgpeth, Pulley, Puffer Lee to 18942 1936-414 19405 1941-426* 1946-487* 18921 1935' 1947-50 1951-529 1951-531o Species Bay Salinity Range

Unknown Unknown 2-25*/.. 5-35*/.. 5-35*/.. 7-390/0 9-400/.. 2-25%/o 20-42/.. 20-42?/. Occurrence Gulf Gulf Gulf Gulf Bay Bay I Bay Gulf Bay GulfBayGulBay1GulfIBay I Bay Gulf Bay Gulf Bay Gulf Bay Chione clenchi x A Cyclinella tenuis D D D X X Dosinia discus D D X A D X X D D A L Macrocallista nimbosa D X D D Pilar texasiana X X D D D Pitar cordata X A Mercenaria campechiensistexana A D A X D A X X D A D A Coraliophagacoraliophaga X RupelUariatypicum X L Petricola pholadiformis D A X X D X D Anatina canaliculata D D D X D X D D Analina lineata X D A D Mactra brasiliana D A D X X D D D A Mulinia lateralis D A D A X D A A A Rangia cuneala A A A X D A D D Spisula solidissima raveneli X D D Donax texasiana D A X X D X D D A D Tagelus divisus X L L Tagelus gibbus D A X D D X X D D D A Abra aequalis D A D X L A L Cumingia tellinoides D D X Semele proficua D X X L L Semele purpurescens D X X D Macoma constricta A D D X D D D D Macoma mitchelli A A X A A Macoma tageliformis D X D D TeUidoracristata A X L D L Tel!ina alternata D A X A X D L A L Tellina lineata D X X D Tellina versicolor D D X A A L Ensis minor A A A X X D A D A Corbula conradi D A A Barnea rostata D A X X D D X X D D D D Pholas campechiensis D X X D D Marlesia smithii A A A Lyonsia floridana D A X A Pandora trilineata X D A X X A D A Periploma inaequalis D D X X D L A L CEPHALOPODA Spirula spirula D D D X D X D D Loliguncula brevis A A X A A A A A A Loligo peali X A A A Odopus vulgaris X A A A A AMPHINEURA Ischnochiton papillosa A A A A

This content downloaded from 132.174.255.3 on Wed, 18 Jun 2014 21:28:38 PM All use subject to JSTOR Terms and Conditions SALINITY AFFECTS ON TEXAS BA Y FA UNAS 209 quite abundant in upper San Antonio Bay, salinity exists in the pelecypod, Mulinia but in 1951, no living examples were found. lateralis, although the salinity range is far It is not certain, however, whether the liv- greater (from 5 to at least 600/oo). Examples ing populations of Rangia and Littoridina of Mulinia from the hypersaline lagoon, have disappeared as a result of increased Laguna Madre, south Texas, all tend to be salinities, or from some other causes. much smaller than those from the waters of more normal salinity further north. III. POSSIBLE PALEOECOLOGICAL As previously mentioned, C. virginica INTERPRETATIONS appears to undergo considerable variation Observations of the sort noted in this paper in shell shape with extreme variation in should be of some value in analyzing the salinity. A similar change was also noted by environments in which fossil assemblages Hedgpeth (1953 and personal communica- existed during Pleistocene and possibly tion) in a small oyster reef situated in the Pliocene times. Puffer and Emerson (1953) hypersaline waters of the Laguna Madre observed that the faunal aggregations pres- near Port Isabel, Texas. It is also possible ent during extended periods of low salinity that the oysters undergo this change in shell appear to differ from those present during shape when the salinity varies intensely in periods of high salinity. As they indicated, either direction. large numbers of Ostrea equestris on top of It has also been observed by Gunter the reefs of Crassostrea virginica indicate (1938) that the oyster assumes a different increased salinities. In fossil assemblages, shape under varying sediment conditions. the echinoderms, corals, and the Gulf mol- Oysters which become buried under mud lusks now found living in the bays may during rapid sedimentation will grow very also constitute valid criteria for recog- long and narrow in order to maintain their nizing essentially marine conditions in water intake above the surface of the bot- former estuarine waters. Associated with tom. If oysters of this shape (commonly these faunal changes indicative of salinity called "coon" oysters) are found in fossil change is the Rangia-Littoridina community assemblages, it might be assumed that the of upper San Antonio Bay which evidently reef had undergone rapid silting. A some- disappears under increased salinity condi- what similar phenomenon has been observed tions. Whereas Ostrea equestris, marine mol- in Copano Bay during periods of very low lusks such as Strombus alatus Gmelin, Sinum salinity, when oysters supposedly grew too perspectivum Say, Simnia uniplicata Sower- rapidly and formed dense clusters of long by, Tellidora cristata Recluz, and Tellina thin individuals. In the case of the silting of versicolor Dekay, echinoderms, and corals oysters, the dense clusters are not formed. indicate salinities of from 30 high to 40oo,0 The dense clustering and elongation of the the Rangia-Littoridina assemblage appears individuals in the cluster may be related to to be a good indicator of very low salinities food supply, which may become more abun- of from 3 to 80/oo. Changes in size of certain dant at low salinities. It may be noted here mollusks also appear to be asssociated with that the "coon" oysters differ somewhat in prolonged salinity changes. It has been appearance from those affected by the pro- noted by Ladd (1951), Mitchell (1894), and longed high salinities, in that in the "coon" the author, for example, that Rangia attains oyster the whole shell is elongated and thin a far greater size in waters of very low rather than only the lips. salinity, or in almost fresh water, than it does in more saline waters. From the center of SUMMARY San Antonio Bay to the delta of the Guad- 1.-Published and unpublished salinity alupe River and into the main mouth of values from the bays and open Gulf of the Guadalupe in Mission Lake, Rangia be- Mexico of the central Texas coast from comes progressively larger. This relation- 1922 until 1953 indicate that during the re- ship may exist because the juveniles are cent six-year drought the salinities have be- killed by the more saline water before at- come much higher than prior to 1948. Pre- taining the normal size attained in nearly vious studies have shown that salinities fresh water. A similar relationship of size to in the bays generally rose above 340/oo in the

This content downloaded from 132.174.255.3 on Wed, 18 Jun 2014 21:28:38 PM All use subject to JSTOR Terms and Conditions 210 ROBERT H. PARKER summer months, but during most of the 7.-Such observations may have some year ranged from 5 to 250/oo. From 1948 to significance to the paleoecologist in inter- 1953, salinities increased to well over 360/oo preting environmental changes associated and at times above 400/oo, without any with changes in the fossil assemblages. appreciable decrease in the winter months. 2.-Comparisons of the total monthly dis- REFERENCES charge from the rivers emptying into these AMEMIYA,IKUSAKA, 1926, Notes on experiments bays, with the total monthly rainfall from on the early developmental stages of the Por- areas in the basin tuguese, American, and English native oysters, representative drainage with special reference to the effect of varying of the rivers for all years of salinity data, salinity: Jour. Mar. Bio. Assoc. United King- indicate that when river discharge and dom, vol. 14, pp. 161-175. associated rainfall were high, the salinities BAKER, BYRONB., JR., 1949, Texas Game, Fish were low for months; and and Oyster Commission, oyster investigation corresponding for the fiscal year, 1948-1949: Mimeo. report. conversely, when discharge and rainfall - , 1950, Texas Game, Fish and Oyster Com- were low (as during the last six years) mission, oyster investigation for the fiscal salinities were high. year, 1949-1950: Mimeo. report. 3.-With the increase in the BAUGHMAN,J. L., and BAKER, BYRON B., JR., salinity, 1950, Oysters in Texas: Texas Game, Fish and oysters in the Texas bays were observed to Oyster Comm., Bull. 29, 38 pp. take on different shell characteristics such BURKENROAD,MARTIN D., 1951, Some principles as thin, colored, and crenu- of marine fishery biology: Inst. Mar. Sci., sharp, highly vol. no. 177-212. lated valves. Publ., 2, 1, pp. COLLIER, ALBERT, and HEDGPETH, JOEL W., 4.-During low-salinity years, the reefs 1950, An introduction to the hydrographyof were composed primarily of Crassostrea tidal waters of Texas: Inst. Mar. Sci., Publ., a vol. 1, no. 2, pp. 121-194. virginica, typically euryhaline species, A check- whereas with the increase in there CROSS,J. C., and PARKS, HAL B., 1939, salinities, list of Texas marine Mollusca: Stephen F. was a corresponding increase in the number Austin State Teachers College, Tech. Bull., of small marine oysters, Ostrea equestris, a vol. 1, Tech. Rept. no. 2. characteristic of waters of DAUGHERTY, F. M., JR., 1952, Notes on Cal- species higher in Aransas In it was observed that well linectes danae Smith Bay, Texas, salinity. 1952, and adjacent waters: Texas Jour. Sci., vol. 4, over half of the spat-size oysters were pp. 264-267. Ostrea equestris. GALTSOFF,PAUL S., 1931, A survey of oyster bot- Fish. vol. 5.-During the period of extended high toms in Texas: Bur. of Inv. Rept., 6, in Aransas pp. 1-30. salinity Bay, many organisms - , 1942, Oyster industry and problems of were collected which had not been pre- management of public oyster reefs in Texas: viously noted from this area. The organisms Typed report in files of Texas Game and Fish most indicative of salinities were the Commission, Rockport, Texas. high Comments on the echinoderms and coelenterates. GUNTER,GORDON, 1938, shape, Many growth and quality of the American oyster: species of gastropods and pelecypods, which Science, vol. 88, pp. 546-547. had been confined to the open Gulf and in- - , 1942, Seasonal condition of Texas oysters: were found Aransas and Texas Acad. Sci., Proc., vol. 25, pp. 89-93. lets, throughout - Studies on marine fishes of Texas: was , 1945, Copano bays. There also a correspond- Inst. Mar. Sci., Publ., vol. 1, no. 1, pp. 1-190. ing decrease and disappearance of low- - , 1950a, Seasonal population changes and salinity mollusks in San Antonio Bay which distributions as related to salinity of certain had been abundant. Whether this invertebrates of the Texas coast, including the formerly commercial Inst. Mar. Sci., Publ., vol. of mollusks from shrimp: disappearance low-salinity 1, no. 2, pp. 7-51. the now high-salinity San Antonio Bay is a - , 1950b, Distribution and abundance of direct result of salinity increase is also not fishes on the Aransas National Wildlife Refuge, known. with life-history notes: Inst. Mar. Sci., Publ., vol. 1, no. 2, pp. 89-101. 6.-Penaeus setiferus, the commercial - , 1953, The relationship of the Bonnet Carre white shrimp, virtually disappeared from Spillway to oyster beds in Mississippi Sound the bays with the increase in salinity, while and the "Louisiana Marsh" with a report on 1950 Inst. Mar. vol. Callinectes danae, a more or less open Gulf the opening: Sci., Publ., 3, no. 1, pp. 17-71. became abundant in the the marine crab, extremely HEDGPETH, JOEL W., 1950, Notes on bays. invertebrate fauna of'salt-flat areas in Aransas

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NationalWildlife Refuge, Texas: Inst. Mar. doctoral dissertation, Harvard University, pp. Sci., Publ., vol. 1, no. 2, pp. 102-119. 1-215, 19 pls. - , 1953, An introductionto the zoogeography REED, CLYDET., 1941, Marinelife in Texas of the northwesternGulf of Mexico with refer- waters: Texas Acad. Publ. in Nat. Hist., non- ence to the invertebratefauna: Inst. Mar. Sci., tech. ser., pp. i-xii, 1-88. Publ., vol. 3, no. 1, pp. 111-224. SIMMONS,ERNEST G., 1951, Annual reportfor the HILDEBRAND,H. H., and GUNTER,G., 1953, Cor- fiscal year September 1, 1940-August 31, 1950; relation of rainfall with Texas catch of white Fish trap investigations:Texas Game and Fish shrimp, Penaeus setiferus (Linnaeus): Amer. Comm., Mimeo report. Fish. Soc., Trans., vol. 85, pp. 151-155. -, 1952, Annual report for the fiscal year KORRINGA,P., 1952, Recent advances in oyster September 1, 1950-August 31, 1951; Fish trap biology: Quart. Rev. Biol., vol. 27, pp. 266-308, investigation: Texas Game and Fish Comm., pp. 339-365. Mimeo. report. LADD, HARRY S., 1951, Brackish water and SINGLEY, J. A., 1892, Texas Mollusca: Texas marine assemblages of the Texas coast with Geol. Surv., 4th Ann. Rept., pp. 297-343. special reference to mollusks: Inst. Mar. Sci., STRECKER,J. K., 1935, Notes on the zoology of Publ., vol. 2, no. 1, pp. 125-164. Texas: Baylor Bull., vol. 38, no. 3, pp. i-vii, McRAE,E. D., 1952, Annual report for the fiscal 1-79. year, September 1, 1950, to August 31, 1951; UNITEDSTATES GEOLOGICAL SURVEY. Shrimp investigation: Texas Game and Fish Surface water supply of the United States- Comm., Mimeo. report. Western Gulf of Mexico basins: Water Supply MILES, DEWEY W., 1951. Annual report for the Papers: 808, 1936; 828, 1937; 858, 1938; 878, fiscal year September 1, 1949-August 31, 1950; 1939; 898, 1940; 928, 1941; 958, 1942; 978, Life histories of the spotted sea trout, Cynosci- 1943; 1008, 1944; 1038, 1945; 1058, 1946; 1088, on nebulosus,and the redfish, Scianops ocel- 1947; 1118, 1948; 1148, 1949; 1178, 1950; 1212, latus: Texas Game, Fish and Oyster Comm., 1951. Mimeo. report. UNITEDSTATES WEATHER BUREAU. MITCHELL,J. D., 1894, List of Texas Mollusca, 1952, Local climatological summary with com- Victoria, Texas: Times Steam Print, vol. 22. parative data: Victoria, Texas, 4 pp. U. AND W. PHLEGER,FRED B., 1951, Ecology of Foramin- WHITEHOUSE, GRANT, WILLIAMS, T., ifera, northwest Gulf of Mexico; Part I, 1953, Descriptive physical oceanography of Foraminifera distribution: Geol. Soc. San Antonio Bay, Mesquite Bay, and Aransas Amer., and waters: Texas Mem. 46, pp. i-ix, 1-88, pls. 1-20. Bay, Texas, adjacent A. & M. of ELTON and WILLIAM College, Department Oceanography, PUFFER, L., EMERSON, K., Project 34B Technical Report 1, Mimeo. re- 1953, The molluscancommunity of the oyster- 21 reef biotope on the central Texas coast: port, pp. Jour. WHITTEN,H. L., ROSENE,H. F., AND HEDGPETH, Paleontology, vol. 27, pp. 536-544, pl. 56. Invertebrate fauna of the Texas THOMAS Shelled JOELW., 1950, PULLEY, E., 1949, mollusks of coast jetties; a preliminary survey: Inst. Mar. the Texas coast from Galveston to Port Aran- Sci., Publ., vol. no. 53-87. sas: Texas vol. 62-68. 1, 2, pp. Jour. Sci., 1, pp. WILLIAMS,W. T., AND WHITEHOUSE, U. G., -, 1952, An illustrated check list of the 1952, Analysis and interpretation of physical marine mollusks of Texas: Texas Jour. Sci., oceanographic data from the Rockport area: vol. 4, pp. 167-199, 13 pls. American Petroleum Institute, Project 51, , 1953, A zoogeographicstudy based on the Fourth Quarterly Report, Appendix IV, pp. bivalves of the Gulf of Mexico: Unpublished 28-38, Mimeo. report.

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