Tn ' ., . ; ' . .. I ~· . \ ~ I I ! ·• , r: ;..'I ' • j ,...... i' '; 1 l,:~:_t 7..Jf.1 ; \·!J .. ~!\~~i r:{ ~~:1: rt'_E.X1~.~; .\.'r .'\lfSr!~!I'-: !\'l!i.?'"_;> ~ !~~ :... {·_·!;_~·· · (:~. ·;j':S"'!'~ f[J l·f. ~~\) i~~'I' ~·\ C:.:'\ ~~-:_; ; ··~ .,~ ~1-I·.. ,\:1\ ~: 73J /:, .. i 26·; Synthesis of data on Acartia tonsa in Texas bay systems: correlation between its abundance and selected environmental factors by W. Y. Lee, Principal Investigator C. R. Arnold, Co-Investigator R. D. Kalke, Co-Investigator The University of Texas at Austin Marine Science Institute Port Aransas, Texas 78373-1267 to Texas Water Development Board P. 0. Box 13087 Capitol Station Austin, Texas 78711 Contract No. IAC (86-87) 1079 TWDB Contract #14-60011 Ll!lr'.AR I PORT A SAS, txAS 7 J73-i.51.i Introduction Acartia tonsa is widely distributed in the coastal waters of the world oceans (McAlice, 1981 ). Along the Atlantic coast of America, it occurs from the Miramichi River estuary, New Brunswick (Bousfield, 1955) down to Bahia Forforescente, Puerto Rico (Gonzalez and Bowman, 1965). In Texas estuaries, it is abundant year-round in places where salinity ranges from 10-30%0 as weil as in hypersaline environment of Laguna Madre and Baffin Bay where salinity may vary from 30 to 80%0. A. tonsa is considered to be an important food item for many larval fish such as Gulf menhaden (Brevoortia patronus), spot (Leiostomus xanthurus), Atlantic croaker (Micropogonias undulatus) and red drum (Sciaenops ocellatus) (Bass and Avault, 1975; Govoni et al., 1983, 1986; Steen and Laroche, 1983). Acartia is also an important component of estuarine zooplankters, which feed mainly on phytoplankton and may sometimes control phytoplankton species composition and size distribution through grazing (Steele and Frost, 1977; Ryther and Sanders, 1980). This study is being carried out to compare the adaptation of A. tonsa to the various temperatures and salinities encountered in six of the Texas estuarine systems. For this purpose, it is hypothesized that the copepod in each of the estuarine environments is actually different from one another in terms of physiology and reproduction. Indeed, they are probably subspecies adapted to local environmental conditions. Some published data did indicate this tendency and listed below are some supporting evidences of this theory. l. Salinity tolerance of A. tonsa varied with both time and location of samples, and thermal prehistory of the copepods affected their survival in diluted seawater (Lance, 1964). 2. Interbreeding of Acartia clausi between populations from east and west coasts resulted in inviable offspring (Carrillo B. -G. et al., 1974). 3. A widespread copepod, Scottolana canadensis, showed significant genetic differentiation in its embryonic duration, egg size and newborn survival, when taken from a broad range of latitude and raised under the same experimental conditions (Lonsdale and Levinton, 1985). A. tonsa in this study comes from six estuaries along the Texas coast; namely, Sabine, Trinity, Matagorda, San Antonio, Corpus Christi and Nueces Bays. Acartia abundance in each system is analyzed with emphasis on: l. Seasonal pattern of the copepod, and variation in temperature and salinity. 2. Relative importance of temperature and salinity to the variation in Acartia populations and 3. Contour maps representing Acartia abundance at various temperature-salinity regimes. The contour maps may be used for predictions regarding copepod seasonality, optimal copepod survival and possible responses of Acartia to salinity changes caused by freshwater inflow to the system. Materials and Methods The analytical procedures described below are designed to produce information necessary for evaluation of the hypothesis made in the previous section. Data entry. Data provided by TWDB are first transferred from external tape to permanent files of the CDC Dual Cyber computer system, and then loaded to mini-disk of the IBM system 370. These data are finally reorganized and statistically analyzed using SAS software package (version 4). Salinity and temperature effects. Stepwise multiple regressions are employed using SAS/GLM procedure. The percent of variance in Acartia associated with each of the environmental factors or with their combined effects is also evaluated and tested by the F-ratio statistic. The relative importance of temperature and salinity to copepod abundance is compared by the method of principal component analysis contained in the same SAS software package. Contour plot. A contour map of Acartia abundance over salinity and temperature possibly encountered in each of the environments is generated using SAS/Graphic programs. There are 7-8 zones defined for each estuarine system, with temperatures ranging from 0 to 36°C and salinity from 0 to 35%0. Results Corpus Christi Bay. Samples were collected during the period from 15 October 1975 to 22 June 1976. Data of 1975 covered October, November and December only, while samples of 1976 covered January (2 times), February (2 times), March, April, May (3 times) and June (2 times). A total of 96 samples were collected from the 5 stations: 53, 127, 142, 147 and 200. Variations in water temperature during the sampling period are shown in Figure l; mean lowest temperature of 9.3°C was recorded during the winter and highest (28.8°C) was observed in the summer of 1976. In contrast with changes of water temperature, mean salinities in Corpus Christi Bay were generally very consistent during the 1975-1976 period (Fig. 2), with overall mean around 30%0. Lower salinity did occur in late spring of 1976, in which case salinity as low as 8.4%0 was recorded in part of the bay. Seasonal variations of A. tonsa in Corpus Christi Bay are shown in Figure 3. On pooled data basis, sampling dates have significant effect on Acartia abundance (F = 3.59, P < 0.0 l ), suggesting that seasonal variations of copepod abundance are significant. On the contrary, collecting sites within the bay are not found to be significantly different from each other in Acartia abundance (F = 2.22, P > 0.07), indicating possible homogeneous distribution of A. tonsa in Corpus Christi Bay. The relationships among Acartia abundance, temperature and salinity can be best described by: Acartia abundance= 1421.5 + 3542.2 x Temperature -167.9 x (Temperature)2 -1777.3 x Salinity -2.4 x (Salinity)2 + 118.5 x Temperature x Salinity (F = 3.36, P < 0.0 l ). The corresponding response curves are shown in Figure 4. Analysis on the · relative importance of temperature and salinity to Acartia abundance (Fig. 5) further suggests that temperature is the component contributing more to Acartia variations in Corpus Christi Bay (Eigenvectors: temperature (0.9997) vs. salinity (0.0210)). LIBRARY THE UNIVCRS 'T'." Ct T ""' S /'.T i,IJS ih ~ PORT ARA1 SA , EXAS 78373-l267, Nueces Bay. Samples were collected between 20 December 1972 to 7 October 1974 from 20 stations. A total of 709 observations were made in the Nueces Bay during this sampling period. Mean temperature variations in the bay were similar in both 1973 and 197 4 (Fig. 6). Temperatures were low during winter and averaged about 7 .5°C in 1972-73 and 12.5°C in 1973-74, and then gradually increased to maximum during the summer months; the mean summer temperature was 29.2°C. Salinities within the bay varied greatly with both seasons and stations (Fig. 7). Annual changes in salinity were also significant. For example, salinities recorded during the winter of 1972-1973 were much higher than those of 1973-1974 and the differences might amount to ± 100/oo on several occasions. As those in Corpus Christi Bay, Acartia populations in Nueces Bay were rather evenly distributed among stations (Fig. 8). One-way ANOVA indicates ''that there is no strong relationship between Acartia abundance and sampling stations (F 1.59, P > 0.05). However, seasonal variations of the copepod are found to be significant at 1% level. The optimal response equation of Acartia to temperature and salinity is depicted in Figure 9 and is defined by: Acartia abundance = 4300.1 + 129.9 x Temperature -5.6 x (Temperature)2 + 88.9 x Salinity -15.6 x (Salinity)2 + 17.1 x Temperature x Salinity (F = 14.45, P < 0.0 l ). Principal component analysis results in no surprise that salinity is contributing more to the variations of Acartia abundance rn Nueces Bay. Eigenvectors are -0.1630 and 0.9866 for temperature and salinity respectively (Fig. IO). San Antonio Bay. Seasonal changes of temperature in San Antonio Bay is presented in Figure 11, and the patterns are very similar to that observed in Nueces Bay. Season highs of 33°C were recorded during summer while lows (about 6.5°C) were found during winter. Seasonal variations in salinity are shown in Figure 12. Salinity near the river mouth was negligible, and it increased gradually outward in response to river flow. Salinities were low, often less than 10%0 during the sampling period. Salinities > 20%0 were only occasionally recorded during winter and early spring of 1973. Copepods in the San Antonio Bay were obtained from 11 stations and on 63 different cruises during the 1972-1974 period. One-way ANOVA shows that dates of collection, but not sampling sites, have significant impact on the variations of Acartia population (F = 2.66, P < 0.01). In general, A. tonsa were higher in late spring and summer than in winter; the highest densities may sometimes reach over 50,000/m3, while a minimum of zero density could also occur (Fig. 13). The response equation of Acartia to temperature and salinity is shown below, and the corresponding contour map is presented in Figure 14. Acartia abundance = -4183.1 + 154.1 x temperature + 3.3 x (Temperature)2 + 1071.5 x Salinity -36.9 x (Salinity)2 + 0.4 x Temperature x Salinity (F = 11.97, P < 0.01 ). As is the case in Nueces Bay, salinity is the major factor in determining the variation of A. tonsa in the system. Eigenvectors from principal component analysis are -0.4648 for temperature and 0.8853 for salinity (Fig. 15). Matagorda Bay. Seasonal changes in temperature, salinity and Acartia abundance from 21 February 1973 to 5 June 1976 are presented in Figures 16, 17 and 18. A total of 426 samples were collected during this period covering 19 stations in the Matagorda Bay. Seasonal temperatures ranged from 7°C recorded in the winter of 1975­1976 to 3 l .5°C in the summer of 1975. Salinity also varied greatly with both seasons and stations, and spanned from near freshwater to about 25%0. Acartia abundance in Matagorda Bay was low compared to that of other estuarine systems described above. The mean densities were generally below l000/m3 for most of the times during the year. Higher densities did occur sometimes during the summer, as the cases noted in the early summer of 1976. One-way ANOVA indicates that differences in Acartia abundance between stations were not significant during the sampling period (F = 1.53, P > 0.07). A significant relationship, however, is observed between copepod abundance and seasons (F 3.51, p < 0.01). The relationship among copepods, temperature, and salinity is shown in Figure 19 and is best defined by the following equation: Acartia abundance = 136.8 + 3.6x Temperature + 0.2 x (Temperature)2 -82.8 x Salinity + 3.5 x (Salinity)2 + 1.5 x Temperature x Salinity (F = 11.31, P < 0.01). Again, it is the salinity which plays a more important role in determining the variation of Acartia abundance in the Matagorda Bay. Eigenvectors from principal component analysis are -0.2867 for temperature and 0.9580 for salinity. The corresponding plot is presented in Figure 20. Trinity Bay. A total of 328 samples were obtained from 6 stations in the Trinity Bay during the 1975-1976 period. Mean temperatures in the bay ranged from about l l.0°C during winter to 30.4°C in August. These variations in water temperature in 1975-1976 are shown in Figure 21. Mean salinities in Trinity Bay varied from 3.8%o to 14.8%0; peak salinity occurred in February 1976 and then declined to the low o: about 3.8%o in July 1976. In 1975 mean salinities recorded during the fall were between 8.6 to 12.3%0 (Fig. 22). Throughout the sampling period, Acartia tonsa were low in their densities (Fig. 23); mean densities were seldom over 400/m3. One-way ANOVA suggests that both collection sites and dates have significant effects on the variation in Acartia abundance; both factors are significant at l % level. The relationship among the A. tonsa abundance, temperature and salinity can be defined as follows: Acartia abundance = -302.2 + 10.8 x Temperature + 0.1 x (Temperature)2 + 36.3 x Salinity -0.8 x (Salinity)2 ­ 0.9 x Temperature x Salinity (F = 14.00, P < 0.01). The contour map corresponding to the above equation is presented in Figure 24. PCA (Fig. 25) suggests that temperature is a more important factor than salinity in influencing the variation in Acartia abundance (Eigenvectors: temperature (0.9131) vs. salinity (-0.4076). Sabine System. Temperatures in Sabine system follow a similar pattern observed in other Texas bay systems; highs were recorded in August and lows were in December and January. Mean temperatures during the year ranged from 11.5 to about 32°C (Fig. 26). Salinities were generally low and often below IOo/oo (Fig. 27); salinities greater than .. 100/oo were occasionally recorded during October 1974, and July and August 1976. Salinities remained below 2%o in winter and spring of 1974­1975, while in the winter of 1975-1976, mean salinities were well above 6%0. A total of 167 samples were collected from 13 stations during the 1974­1976 period. Seasonal variations in A. tonsa abundance are shown in Figure 28. As is the case in the Trinity Bay, A. tonsa in the Sabine system varies significantly both from season to season (F = 10.39, P < 0.0 l) and from station to station (F = 2.98, P < 0.0 l ). The following equation best describes the relationship of Acartia abundance to the two factors of temperature and salinity. Acartia abundance = -359.7 + 30.9 x Temperature -0.6 x (Temperature)2 + 26.7 x Salinity -1.1 x (Salinity)2 -0.1 x Temperature x Salinity (F 22.98, p < 0.01). Figure 29 is the contour plot representing the possible response of Acartia to changes in temperature and salinity. Principal component analysis (Fig. 30) shows that temperature plays an important role in determining Acartia abundance in the Sabine estuarine system. Eigenvectors from PCA are 0.9871 for temperature and -0.1599 for salinity. Discussion and Conclusion The copepod Acartia tonsa is the most important estuarine zooplankter along the Atlantic coast (Ambler, 1985; Breuer, 1957, 1962; Conover, 1956; Cooper, 1967; Cronin, 1962; Deevey, 1952, 1960; Fish, 1925; Heinle, 1966; Holland et al., 1974; Jeffries, 1962; Lee and McAlice, 1979; Livingston, 1981; Martin, 1965; Mcilwain, 1968; Sage and Herman, 1972; Woodmansee, 1958). Factors controlling seasonal succession and abundance of the copepod have been related to food resources, predators, prey density, temperature and salinity (Durbin et al., 1983; Johnson, 1980; Knatz, 1978; Lance, 1964; Martin, 1965; Sullivan and McManus, 1986). In this study, we examine only the historical zooplankton data and endeavor to determine if there is strong association between the Acartia abundance and the two environmental factors; temperature and salinity. The historical data are analyzed under the assumptions that I) zooplankton were collected with the same gear type and in the same manner throughout the estuarine systems and the sampling periods, 2) sampling sites were randomly selected and were representative of conditions possibly encountered in the system and 3) sampling intervals of 2 to 8 weeks, as wa~ the case in this study, would not greatly affect the fidelity of the response model built for Acartia populations. Significant seasonal variations of both temperature and salinity were noted in each drainage system in this study, with the exception of salinity changes in Corpus Christi Bay (F = 1.32, P > 0.216). The high (> 25%0) and nearly constant salinity recorded between October 1975 and June 1976 may explain the case encountered in Corpus Christi Bay. ANOVA results also indicate significant seasonal variations in Acartia abundance among the 6 estuarine systems. If all data were pooled together, the association of Acartia population with temperature and salinity can be represented in the contour map (Fig. 31) and defined by the following equation: Acartia abundance = -63.880 + 151.541 x Temperature -3.916 x (Temperature)2 -231.507 x Salinity+ 6.044 x (Salinity)2 + 13.062 x Temperature x Salinity Principal component analysis over all data points reveals that salinity is more important than temperature in regulating variations in Acartia abundance. Eigenvectors are -0.196 for temperature and 0.981 for salinity (Fig. 32). It appears that freshwater inflow will have great impact on the population dynamics of A. tonsa in Texas estuarine systems. However, on pooled data basis, the results often conceal important processes which might be characteristic to the individual system. For this reason, individual systems are treated separately and summarized as follows: 1. Systems in which Acartia tonsa shows significant seasonal variation include Corpus Christi, Nueces, San Antonio and Matagorda Bays 2. Systems in which the Acartia population varies significantly with both seasons and locations include Sabine and Trinity Bays 3. Systems in which temperature is a more important factor in determining variations in Acartia abundance include Corpus Christi, Sabine and Trinity Bays 4. Systems in which salinity plays a more important role than temperature in determining variations in Acartia abundance include Nueces, San Antonio and Matagorda Bays. Using Duncan's multiple range test, the 6 draining systems can be further classified into 4 groups: A) Corpus Christi Bay B) Nueces C) San Antonio D) Matagorda, Sabine and Trinity bays. The detailed results are given as follows: Group Mean Acartia Number of Location Density Observations A 15,916 96 Corpus Christi B 6,296 708 Nueces c 5, 113 330 San Antonio D 423 419 Matagorda D 75 167 Sabine D 42 328 Trinity The social implications of this project are its most important aspect; the end product suggests that freshwater inflow is important to the estuarine zooplankter Acartia tonsa m Texas estuaries. The results also indicate that A. tonsa in each drainage system will respond differently to salinity variation accompanied by temperature changes as shown in the contour maps. These results should provide various government agencies with critical data needed in evaluating the possible environmental impacts of man's activities on the ecosystem of estuaries. The implications to society are also significant; alteration of the estuarine habitats may lead to changes not only in zooplankton population but also m larvae or juveniles of economically-important fish which feed on Acartia tonsa or other estuarine zooplankters. References Ambler, J.W. 1985. Seasonal factors affecting egg production and viability of eggs of Acartia to11Sa Dana from East Lagoon, Galveston, Texas. Estu. Coast Shelf Sci. 20:743-760. Bass, R.J. and J.W. Avault, Jr. 1975. Food habits, length-weight relationship, condition factor, and growth of juvenile red drum, Sciaenops ocellatus, in Louisiana. Trans. Amer. Fish. Soc. 104:35-45. Bousfield, E.L. 1955. Ecological control of the occurrence of barnacles in the Miramichi estuary. Bull. natn. Mus. Can. 137: 1-69. Breuer, J.P. 1957. An ecological survey of Baffin and Alazan Bays, Texas. Contr. Mar. Sci. 4:134-155. Breuer, J.P. 1962. An ecological survey of the lower Laguna Madre of Texas, 1953-1959. Contr. Mar. Sci. 8:153-183. Carrillo, B.-G., C.B. Miller and P.H. Wiebe. 1974. Failure of interbreeding between Atlantic and Pacific populations of the marine calanoid copepod Acartia c/ausi Giesbrecht. Limnol. Oceanogr. 19:452-458. Conover, R.J. 1956. Oceanography of Long Island Sound, 1952-1954. VI. Biology of Acartia clausi and A. tonsa. Bull. Bingham Oceanogr. Coll. 15: 156-233. Cooper, D.C. 1967. Ecological parameters concerning the zooplankton community of the San Antonio estuarine system. M.A. thesis, University of Texas at Austin, 124 pp. Cronin, L.E., J.D. Daiber and E.M. Hulburt. 1962. Quantitative seasonal aspects of zooplankton in the Delaware River estuary. Ches. Sci. 3:63-93. Dagg, M.J. 1977. Some effects of patchy food environments on copepods. Lim no I. Oceanogr. 22:99-107. Deevey, G.B.A. 1952. A survey of the zooplankton of Block Island Sound, 1943-1946. Bull. Bingham Oceanogr. Coll. 13:65-119. Deevey, G.B.A. 1960. The zooplankton of the surface waters of the Delaware Bay region. Bull. Bingham Oceanogr. Coll. 17:5-53. Durbin, E.G., A.G. Durbin, T.J. Smayda and P.G. Verity. 1983. Food limitation of production by adult Acartia tonsa in Narragansett Bay, Rhode Island. Limnol. Oceanogr. 28: 1199-1213. Fish, C.J. 1925. Seasonal distribution of the plankton of the Woods Hole region. Bull. Bur. Fish. Wash. 41 :91-179. Gonzalez, J.G. and T.E. Bowman. 1965. Planktonic copepods from Bahia Fosforescente, Puerto Rico, and adjacent waters. Proc. U.S. Natl. Mus. 117:241-303. Govoni, J.J., D.E. Hoss and A.J. Chester. 1983. Comparative feeding of three species of larval fishes in the northern Gulf of Mexico: Brevoortia patronus, Leiostomus xanthurus, and Micropogonias undulatus. Mar. Ecol. Prog. Ser. 13:189-199. Govoni, J.J., P.B. Ortner, F. Al-Yamani and L.C. Hill. 1986. Selective feeding of spot, Leiostomus xanthurus, and Atlantic croaker, Micropogonias undulatus, larvae in the northern Gulf of Mexico. Mar. Ecol. Prog. Ser. 28:175-183. Heinle, D.R. 1966. Production of a calanoid copepod, Acartia tonsa, in the Patuxent River estuary. Ches. Sci. 7:59-74. Holland, J.S., N.J. Maciolek, R.D. Kalke and C.H. Oppenheimer. 1974. Zooplankton. In: A benthos and plankton study of the Corpus Christi, Copano and Aransas Bay systems, pp. 15-43. University of Texas Marine Science Institute, Second Annual Report, Texas Water Development Board. Jeffries, H.P. 1962. Succession of two Acartia species in estuaries. Limnol. Oceanogr. 7:354-364. Johnson, J.K. 1980. Effects of temperature and salinity on production and hatching of dormant eggs of Acartia califomiensis (Copepoda) in an Oregon estuary. Fish. Bull. 77:567-584. Knatz, G. 1978. Succession of copepod species in a middle Atlantic estuary. Estuaries 1:68-71. Lance, J. 1964. The salinity tolerance of some estuarine planktonic cope pods. Limnol. Oceanogr. 8:440-449. Lee, W.Y. and B.J. McAlice. 1979. Seasonal succession and breeding cycles of three species of Acartia (Copepoda: Calanoida) m a Maine estuary. Estuaries 2:228-235. Livingston, G.P. 1981. Distribution of the crustacean zooplankton m a subtropical estuarine system: implications for the predator-prey interaction between the primary and secondary consumers. Ph.D. dissertation, Texas A&M University, 144 pp. Lonsdale, D.J. and J.S. Levinton. 1985. Latitudinal differentiation in embryonic duration, egg size, and newborn survival in a harpacticoid copepod. Biol. Bull. 168:419-431 . Martin, J.H. 1965. Phytoplankton-zooplankton relationships m Narragansett Bay. Limnol. Oceanogr. 10:185-191. McAlice, B.J. 1981. On the post-glacial history of Acartia tonsa (Copepoda: Calanoida) in the Gulf of Maine and the Gulf of St.. Lawrence. Mar. Biol. 64:267 -272. Mcllwain, T.D. 1968. Seasonal occurrence of the pelagic Copepoda in Mississippi Sound. Gulf Res. Rept. 2:257-270. Ryther, J.H. and J.G. Sanders. 1980. Experimental evidence of zooplankton control of the species composition and size distribution of marine phytoplankton. Mar. Ecol. Prog. Ser. 3:279-283. Sage, L.E. and S.S. Herman. 1972. Zooplankton of the Sandy Hook area, N .J. Ches. Sci. 13:29-39. Steele, J.H. and B.W. Frost. 1977. The structure of plankton communities. Phil. Trans. Roy. Soc. London 280(B):485-534. Steen, J.P., Jr. and J.L. Laroche. 1983. The food of red drum (Sciaenops ocel/atus larvae and early juveniles taken from Mississippi Sound and the northern Gulf of Mexico. Proceedings, Northern Gulf of Mexico Estuaries & Barrier Islands Research Conference, pp. 35-38. Sullivan, B.K. and L.T. McManus. 1986. Factors controlling seasonal succession of the copepods Acartia hudsonica and A. tonsa in Narragansett Bay, Rhode Island: temperature and resting egg production. Mar. Ecol. Prag. Ser. 28:121-128. Woodmansee, R.A. 1958. The seasonal distribution of the zooplankton off Chicken Key in Biscayne Bay, Florida. Ecology 39:247-262. SEASONAL CHANGES OF TEMPERATURE IN CORPUS TEMP 30.0-J 27.5 I 25.0j I 22.5 f 20.0 I 17. 5 3 T J t 15.0 I 1 12.Si I 10.0 7.5 ~ 5.0~~.~1-··-·~··~·~·-··-1~··~·-·-··-·~··-1~··~·-·~··-·~··~1~·-··-·~··~·-·-·1-·~··~·~·-··-·~·1~·········1···· 100975 111875 122875 020676 031776 042676 060576 DATE Figure L SEASONAL CHANGES OF SALINITY IN CORPUS SAL 37.51 35.0 32.5 T II I 30.0 j 1 27.5 25.0 22.5 20.0 17.5 15.0 12.5 10.0 j 7.5 5 . 0 Lr-r-r-r..,--,--,~~· I ' I • I I t I I I I t i I I I I I I I I t I .... I ' I I I I I ,-,..-, I i I I I I I I I l I I I ~ ~1 i i I r 1 1 I 1 042772 111372 060173 121873 070674 012275 DATE Figure 7. SEASONAL VARIATION OF ACARTIA IN NUECES BAY ACA 110000 100000 90000 80000 70000 60000 50000 40000 1 30000 20000 10000 I I L. I 0 042772 111 372 060173 121873 070674 012275 DATE Figure 8. RESPONSE OF ACARTIA TO TEMPERATURE AND SALINITY {NUECES BAY) SAL ,. , ,. , ,, ,. ,.' 35.0 ,.," ,,' ,.,. , , ,. , , , ,. , , , ,, , , , , , / , , , , 31. 5 , , , ,, , , , ,,, , ,, , , , , ,. , , / , ,, / , , / , / , ,/ / , / ," / , ,/ 28.0 , / , I / I / , I ,, ,,/ ' / , / , , ,, / ,, / , / , / / ,, / I ,,, ,,./ I , ,, / ,. I ' , / I I ' 24.5 ,. ,,," , ,, , I ' , ,I , , / I ' I , , I , / I I , / I 21.0 -, , ," I I ,,, I .· I j ,." , / / , / I ,, ,, ,, ,, / ~ ,,,, / I I ,, 17.5 , ,,,,, / I I I jl ,, I I I \ I / ' ' I ... ........... I 14. 0 . / I -------··--·· ----­ I I I / I I I ' I I I I I I I 10.5 I r / ! 7. 01 I' I I I I I I 3. 5 ~ \ '\ ---­ o. o j~-r-r-r-r-T-r-.--.-.--,',~,'~,'~-~-~--~-~--~-~--~-~--~-~--~-~-~--~-~--~-~--~-~--~-~--~-~--~-~--~-~--r-r--r~-~-~-r-r--r-.-.--r-r-ir-y-,---.-r--r-r-ir-r--r-­ 0 9 18 27 36 TEMP LEGEND: ACA -----, 1 6 , 4. 2 9 7 -8241.289 -4868.282 -1495.274 -------1877. 733 ·------· 5250. 741 ·------8623. 749 Figure 9. PCA OF TEMPERATURE AND SALINITY ON ACARTIA--NUECES PRIN1 15 12 9 6 3 0 -3 -6 -9 -12 -15 -18 -21 -24 + + ++ + + + :t + + + t++-+-4 kt. +++:tt *+ t +1ft '* + + + + + +:t +:f: + +++ i. + +++ • i= ++t + + + + ':ft .... ~it{+ + +~ +++ ++ t*# ++.~ ++ + +'I" + :t + J+ + + + + * ++..,. .~+ + * ++ ...._.. ++-.t-lf. ~~++ -if-++ +t + ++++f" -f*.P-* •:flt. ~ + + + + ~ + + + + + + :t r: + t. ++*+ + + + '-+ + • ++i::tJt +=k-++ + ++ + + ++ .1Jtt: :tt ++tl + +-Y+:+J + ++ + + ++ .... + + + + it+ + ++ + + :r-,.. ++ + + ++t+ + + + :II-+...... + + + + ++.; ri-+ + + ++ + ++ + ~+.»­ + + + + + + .I-+ +"'+ + -if-+ +++ -t>+ + + + + + + * ++ f t\+ + + + + ++ + + + + +++ +.+ + + + + ++ + +++++ + -+-+-+ + :f: tt± + + + + + + + + +* .f'F.•.ll:f..+ ++ ++ + ++ :\: "*1-\ + 1J. + + -if. + + ++ + + + +++-q..++ + + ++ + + + + + ++ + + +++ + + ii++ :f:f"+ -r*~ + + + + + + + + + + + + ++ + + .t + ++ + + +:t+ *!++:.. ++ + ++ + + .... ~+ -25 -15 -5 5 PRIN2 Figure 10 . SEASONAL CHANGES OF TEMPERATURE IN ANTONIO TEMP 35. 0 32.5 30.0 27.5 25.0 I t!I I ! J1 I ! ·!I r ! t I I 22.5 i 20.0 ~ It 17.5 i I s: 15.0 I 12.5 If 10.0 I± 7.5 I 5.0 2.5 O,Ol.,-r-y-rrrr-,-,-,-,r-TTTTTTT"TTT""r-r-Tr-rrT"l,-m-rrrr-rrr-r-r-rr-m->rr-r-rT"T"T"T-rrT""l""T"rT~rt-rr~~-rw-T-~--I I I I I I I I I I I I 1 I I I' I I I I I I I I I I 030872 061672 092472 010273 041273 072173 102973 020674 051774 DATE Figure 11. SEASONAL CHANGES OF SALINITY IN ANTONIO SAL 32.5-j 30.0 27.5 l 22.5 20.0 17.5 15.0 1 12.5 T 10.0 7.5 5.0 2.5 1 030872 061672 092472 010273 041273 072173 102973 020674 051774 DATE Figure 12. SEASONAL VARIATION OF ACARTIA IN SAN ANTONIO BAY ACA 65000 60000 55000 50000 45000 40000 35000 30000 I 25600 2(5600 15000 10000 030872 061672 092472 010273 041273 072173 102973 020674 051774 DATE Figure 13. RESPONSE OF ACARTIA TO TEMPERATURE AND SALINITY (SAN ANTONIO B Y) SAL -, 35. 0 31. 5 28 . 0 J ; _.... 24.5 ;;; .,,,..-'""' ,,.; ; ;,,.,,. ,,. I ' I I I I I (, . ,... · ,,, ,,... , // . I I,,.// I i II l I \ ' ' ' ' ... ' ' ' ', ... '· ' ' ... ... ' :::L.. .. .. ... ... 0 9 18 27 36 TEMP LEGEND : ACA -12178 -81 02 -4026 51 4 127 8203 12280 Figure 14. PCA OF TEMPERATURE AND SAIJNITY ON ACARTIA--SAN ANTONIO PRIN1 24 21 18 15 12 9 6 3 0 -3 -6 -9 + + + + + .t + + + + + + + + + + + + + + + + + + + + + + + ++ + + + + + + + + + t + + + + + + + + + ++ + + + + + + ++ ++-!J++ + -f + + + + + + ++ + + + + *+ + ++ +.t + + ~ + + + + + ++ ++*. + iltt-+++ + + + + .... ++ + + + + ++++ + + + • ++ ++ + + + itit+:+ + +.+:it + + • :+: +~' + + ++ + + + + ++ +! +++ + + +* ~ +\. ++.{~+ + + + +;t_++ it"t ~+ .+:++ --=""+ + + + =t--b.. +.r~ + .......... ? ..... ++ + + ~ + -25 -15 -5 5 15 PRIN2 Figure 15. SEASONAL CHANGES OF TEMPERATURE IN MATAGORDA TEMP ~ T 32.5j 4 I ~ l I 30. 01 27.51 i tI If 25.01 I I ., d l ~ 22.51 1 l - I 1 I ln 20.01 l IU l r1 ~ 17.51 l I i l_ 15.0~ 1 12.51 ~ 10.0j 7.5 022173 090973 032874 101474 050275 111875 060576 DATE Figure 16. SEASONAL CHANGES OF SALINITY IN MATAGODA SAL 022173 090973 032874 101474 050275 111875 060576 DATE Figure 17. SEASONAL VARIATION OF ACARTIA IN MATAGORDA BAY ACA 11000 10000 9000 8000 7000 6000 5000 4000 050275 111875 060576 RESPONSE OF ACARTIA TO TEMPERATURE AND SALINITY (MATAGORDA BAY) SAL 21. 0 ' 17. s1 14. 01 J I ~I ~ I ,_ 10. s ~ ~ 7. 0 ~ I 3.5 iI o.o ~ . . .. ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,~ 0 9 18 27 36 TEMP LEGEND: ACA -----133. 353 519.678 1172. 709 --1825. 740 -------2478. 771 · ·-----3131.802 -------3784. 833 Figure 19. PCA OF TEMPERATURE AND SALINITY ON ACARTIA--MATAGORDA PRIN1 15.0 12.5 10.0 + + + + 7.5 + + 5 . 0 2.5 + + ++ + 0.0 + + -2.5 + -5.0 -7. 5 -10.0 + + * + + + + + + + + -12.5 -15.0 -17.5 + + + + + t" + + + + + + + + + + + ++ ++ + + + + ++ + + + + + + + + + + +t + -++­ ++ '*-+ + + + -++-+ ++ + ++ + + + + + ++ + + + + + + + + + + + + +++ + + +.t +t-+ + + ++it­ + + + + + + + + + + + + + * + + ++ + + + t + + ++ t ++ + ++ + ++ + ++ + + + + + + + + t ++ + + if. + ++ + + + + + + + + + + + ++ + + + -++­ + + ++ + + + + + + + + + + + + + ++ + ++ + + + + -f.f­ + + t++ + + + * + ++ + * + + + + ++ ++ ++ + + + + ...... + + + +r + + + +++ +t + + + + + t ++ + + + + + + + + + * ++ + -20.0 -12.5 -5.0 2.5 10.0 PRIN2 Figure 20. SEASONAL CHANGES OF TEMP IN TRINITY TEMP 32 30 I 28 26 I 24 I 22 I 20 f 18 16 I • 14 12 I I 10 092975 111875 010776 022676 041676 060576 072576 DATE Figure 21. SEASONAL CHANGES OF SALINITY IN TRINITY SAL 18 17 16 15 14 13 12 11 10 9 8 t 7 6 5 4 l I 3 2 1 1 l 0 092975 111875 010776 022676 041676 060576 072576 DATE Figure 22. SEASONAL VARIATION OF ACARTIA IN TRINITY BAY ACA 550 500 450 400 350 300 250 200 150 100 50 041676 060576 072576 RESPONSE OF ACARTIA TO TEMPERATURE AND SALINITY (TRINITY) SAL PCA OF TEMPERATURE AND SALINITY ON ACARTIA--TRINITY PRIN1 12.5 + 10.0 7.5 + + + ++ + + + + + + + 5.0 2.5 + + + + ++ + + 0.0 + + + + + + + +++ + -2.5 + -5.0 -7.5 ++ + + + + + + + + -10.0 + + ++ + + + + -12.5 -10 -8 -6 -4 -2 0 2 4 6 PRIN2 Figure 25. SEASONAL CHANGES OF TEMPERATURE IN SABINE TEMP 40.0 37.5 35.0 32. 5j j 30.01 27.5-1 ~ 25.01 22.5 20.0 -l ~ 17.5j ...j , 15.0~ , 12.51 ~ 10.0 7.5 I I I I I I l T II l I • I I 1 l I 5. 0 Trr,,.,..,n-TT~.--..-.-.·.....-.,.~., ••~ ••~ ........ , .~,........ ,__,,,.t , ... .-.-..,,,......, ........ T'Tf I.,...,, r-r-rr1 ' ' I ' I I .........~••~.~ ••~ ,........ , '._., .......... ,,......,r-.-1 ,....,,1rr1.-..., ,,..., ••~.I~ ........ 070674 101474 012275 050275 081075 1,11875 022676 060576 091376 DATE Figure 26. SESONAL CHANGES OF SALINITY IN SABINE SAL 22 20 18 16 14 12 10 T T I I I I I I I r 6 I 2 I f It . -I 11 f 0 .... I' I' i I I I I Ii' I I I I I I I I I I I I I I I' I I I I Ii' I I I' I I I I I Ii I I' I I I I I I I I I I I I I I I I I I I I Ii I I I I I I 070674 101474 012275 050275 081075 111875 022676 060576 091376 DATE Figure 27. SEASONAL VARIATION OF ACARTIA IN SABINE BAY ACA 1400 1300 1200 1100 1000 900 800 700 600 500 400 300 200 070674 101474 012275 050275 081075 111875 022676 060576 091376 DATE Figure 28. RESPONSE EQUATION FOR ACARTIA ABUNDANCE WITH TEMP AND SALINITY-SABINE SAL 35. 0 31. 5 ,,__ .., 28.0 ...... ' ... , ....... 24.5 -----------------------·--­ ..... __ ''.... , '',, ',, 21. 0 -_.... -·---------~­ 17.5 ,,_, '',',,, I I ,';/ I I ', I I ,. I I ,. ' I I ,I ' ' I I I ' \ I I I \ I I I I I ' \ I I I I .. I I I II I :' I I I I I I I II I I I I I I II I I I I I I I I I I I I } I I \ I / I \ ' \ I \ I I \ I \ \ \ I \ \ I I ,I I \ ' , I \ , I \ / ,. , \ ' \ \ I \ I '\ ___ .., ,'" \ \ _... ­ \ \ \ ' ',' 3.5 I \ '\',, I \ '\.. ' ' ', ',, ', ....., ',, .........,,....... O.O-+rrr-rr-rrrrr,-,-T-T--r-r-...--.-...--.--r-r-...--.--r-T"-r-w-~~......,.......,.......,.~~~_.,......,_.,......,.....,....,.--.--..--.--..--.--..--.--..--.--..--.--.~~~~...4-1 0 9 18 27 36 TEMP LEGEND: ACA -------785. 7586 -633. 7244 -481.6903 -329.6561 --------177. 6220 ·------· -25. 5878 ·-------· 126. 446 3 Figure 29. PCA OF TEMPERATURE AND SALINITY ON ACARTIA--SABINE PRIN1 15.0 12. 5 10. 0 7.5 5. 0 2.5 0. 0 -2.5 -5.0 -7. 5 -10. 0 -12. 5 -15.0 -17. 5 + + + + + ++ +...­++ + +i if..... .t++ t:tt +..,.. ++ + + + + + + + + + + + . + +++ ++ ++ + + + + + ++ + ++ + + ++ + + + + + + + + ++; ++ + + + ++ ++ + + +t. + -q. .. +++ + + + -l:t-++ + + + + + + + + + l-+ + ++ ++ + + + + -q. + + -t+ + + + -8 --6 -4 -2 0 2 4 6 8 10 12 14 16 18 PRIN2 Fi gure 30. RESPONSE OF ACARTIA ABUNDANCE TO TEMPERATURE AND SAIJNITY SAL 16 -1114.634 --9380. 055 -------19874. 7 44 TEMP LEGEND: ACA 2383.596 ---5881 . 826 -------12878. 285 ·------· 16376. 51 4 Figure 31. PCA OF TEMPERATURE AND SALINITY ON ACARTIA ABUNDANCE PRIN2 + + + -15 -10 -5 0 5 10 15 20 25 PRIN1 Figure 32.