CONTRACT REPORT H-73-1 THE BRACKISH WATER CLAM RANGIA CUNEATA AS INDICATOR OF ECOLOGICAL EFFECTS OF SALINITY CHANGES IN COASTAL WATERS by S. H. Hopkins, J. W. Anderson, K. Horvath i s a ? m <=? IDI L XT Lr u mlM lio i rt> i III muss/BttK ;-V-sasa June 1973 Sponsored by Office, Chief of Engineers, U. S. Army Conducted for U. S. Army Engineer Waterways Experiment Station Vicksburg, Mississippi Under Contract No. DACW39-7I-C-0007 By Department of Biology, Research Foundation, Texas A<S*M University, College Station, Texas , APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED B è ï ï a r y Au g 3 1973 Bureau of Reclamation Denver, Colorado - ..f e :■' \ ".T ” V Destroy this report when no longer needed. Do not return it to the originator. The findings in this report are not to be construed as an officia Department of the Army position unless so designated by other authorized documents. 92041911 THE ^BRACKISH WATER CLAM RANGIA CUNEATA AS INDICATOR OF ECOLOGICAL EFFECTS OF SALINITY CHANGES IN COASTAL WATERS3 by £ S. H. Hopkins, J. W. Anderson, K. Horvath — SCI J 101 I0I[ DÌ00101 June 1973 Sponsored by Office, Chief of Engineers, U. S. Army Conducted for U. S. Army Engineer Waterways Experiment Station Vicksburg, Mississippi Under Contract No. DACW39-7I-C-0007 By Department of Biology, Research Foundation, Texas A<5kM University, College Station, Texas ARMY-MRC VICKSBURG. MISS. APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED L FOREWORD This report was prepared under Contract No. DACW39-71-C-0007 with the Department of Biology, Texas A&M University Research Foundation, College Station, Texas, for the U. S. Army Engineer Waterways Experiment Station (WES). This report was written by Dr. S. H. Hopkins, assisted by the following people, who participated in the investigation. Dr. Jack W. Anderson directed the work on the physiology of Rangia cuneata and some of the work on reproduction and development; Brian Bedford did the major part of the physiological work for a Ph. D. dissertation; and students Susan Baldwin, Thomas M. Dillon, and Glen Michael Hightower aided in the work on physiology and on reproduction, development, and growth. Dr. Kalman Horvath directed the work on the biochemistry of Rangia, also on the ciliary activity and on the measurements from which the condition index was calculated; he was assisted by students Michael P. Klett and Lynn W. Jagers in the physical measurements and the biochemical work and by Kathleen Hooper Julicher in measurements of ciliary activity. C. A. Bedinger collected many of the clams, made a number of ecological observations, and got well along in a study of some biochemical parameters in relation to season and salinity, but did not have his biochemical results complete enough to include in this re- port; he also participated in the study of reproduction and larval de­ velopment. Melvin R. Frei, working in Dr. Horvath's laboratory, com­ pleted a study of crystalline style enzymes in three different popula­ tions of Rangia cuneata, which he used for his Ph. D. dissertation. Jack M. Neagle studied the parasites of these three populations. The introduction, the review of the natural history, and the overall dis­ cussion and conclusions were written by Dr. Hopkins. The typist was Ruth Peschke. The contract was monitored by Mr. F. A. Herrmann, Jr., Chief of the Estuaries Division, under the general supervision of Mr. H. B. Simmons, Chief of the Hydraulics Laboratory. iii Director of WES during the conduct of this study and the publica­ tion of this report was COL Ernest D. Peixotto, CE. Technical Director was Mr. F. R. Brown. iv TABLE OF CONTENTS Page FOREWORD ................................................ i ü SUMMARY ................................................. ix INTRODUCTION ............................................ 1 NATURAL HISTORY .............. 6 Zoology of Rangia .................. 6 Population Density .................................. H Biomass .............................................. 13 Commercial Value ............. 15 Reproduction, Development and Setting ........................................ 17 Growth ............................................... 21 Food and Feeding ................ 25 Fauna of the Rangia Zone ............... 27 Predation ........... 34 Parasites ............................................ 36 Bottom Type Inhabited ............................... 37 Temperature Relations ............................... 38 Salinity Relations ................................... 42 DESCRIPTION OF THE STUDY AREAS ......................... 43 Trinity River Delta-Trinity Bay ........ 43 Trinity Bay .......................................... 44 Trinity River Delta .................................. 47 Lake Anahuac ......... 49 The Neches River ................ 50 PHYSIOLOGICAL STUDIES ON EFFECTS OF SALINITY .......... 57 General Introduction............. 57 General Methods and Materials ......... 58 Effect of Salinity on Blood Osmotic Concentration, Per Cent Water, and Per Cent Ash .................. 59 1. Introduction ................................... 59 2. Materials and Methods ......................... 60 v a. Osmoregulation ........................... 60 b. Body water percentage and ash percentage... 61 3. Results 61 a. Osmoregulation ............................ 61 b. Per cent body water and per cent ash ...... 66 4. Discussion .................................... 70 Effects of Salinity on the Uptake and Accumulation of Glycine .......................................... 75 1. Introduction ................... 75 2. Materials and Methods ........................ 75 a. Uptake of glycine .......................... 75 3. Results .................. 79 a. Uptake of glycine by whole animals ....... 79 b. Uptake of glycine by isolated gill tissue.. 84 c. Velocity of glycine uptake .......... 84 d. Fate of accumulated glycine .............. 89 4. Discussion .................................... 97 Effects of Salinity and Temperature on Respiration... 100 1. Introduction ................................... 100 2. Materials and Methods ......................... 100 a. Whole animal respiration .................. 100 b. Gill respiration .......................... 102 3. Results ........................................ 103 a. Whole animal respiration .................. 103 b. Gill respiration................ 112 4. Discussion .......... 117 Effect of Salinity on Glycogen Utilization by Rangia. 120 1. Introduction ...................... 120 2. Materials and Methods ....................... • 120 3. Results ................. 121 4. Discussion.... ............................... 121 vi Page Effect of Salinity on Feeding .......... 125 1. Introduction ........................ 125 2. Materials and Methods .......... 126 3. Results ...................................... 128 4. Discussion ...... 135 Effects of Salinity on Reproduction, Larval Development and Growth ............................ 136 1. Introduction ................................... 136 2. Materials and Methods .......................... 137 3. Results ...••................................... 138 4. Discussion ..................................... 147 Phytoplankton Studies ................................ 149 1. Introduction ................................... 149 2. Materials and Methods ........................ 149 3. Results .............. 150 4 • Discussion...... .............................. 150 SOME INDICES OF SEASONAL AND ENVIRONMENTAL EFFECTS .... 153 Effects of Salinity and Temperature on Ciliary Activity ................ 153 Introduction ....................................... 153 Methods ........ 153 Results and Discussion ............................ 154 Dissolved Carbohydrate Uptake by Rangia ............. 158 Introduction ................................. 158 Methods ............................................ 158 Results ........... 159 Seasonal Physical-Chemical Parameters of the Com­ position of Rangia ........................ 163 Introduction .................................... 163 Methods ............... 163 Results ............................................ 164 vii Page COMPARATIVE STUDIES OF CRYSTALLINE STYLE ENZYME ACTIVITY IN POPULATIONS FROM WATERS OF DIF­ FERENT SALINITY .................................. 172 Introduction and Literature Review .............. 172 Materials and Methods ......... 174 Results and Discussion .......................... 176 Chlorinity ................... 178 Incubation Time ............................... 187 Ionic Effects .................................. 200 Conclusions ...................................... 205 OVERALL SUMMARY AND DISCUSSION ..................... 212 CONCLUSIONS ......................................... 220 REFERENCES CITED ..... 224 OTHER RANGIA REFERENCES ............................ 245 ADDENDA ................. 250 viii SUMMARY It was apparent to Dr. S. H. Hopkins, a consultant for the Corps of Engineers on the effects of engineering works on biota of coastal waters, that there was seldom as much information on the ecology of estuarine organisms as was needed to predict the effects of environ­ mental changes. The ecology of oysters comes close to being an excep­ tion. Oysters have been the subject of literally thousands of scien­ tific publications. Enough information has been accumulated on their biology and that of their competitors, pests, predators, and parasites to permit fairly confident predictions as to how and how much they will be affected by a given change in the environment, e.g., a rise or drop of 10 ppt (parts per thousand)