FLINT and RABALAIS: GULF OF MEXICO SHRIMP PRODUCTION 



larger ratio for the smaller sized microplankton as 

 found by Droop and Scott (1978) and Mills and 

 Fournier (1979). Benthos standing stocks were 

 converted to annual production using a turnover 

 ratio of 4.5 (Nichols 1977; Arntz 1980). A conver- 

 sion for heads-on weight ( 1.61) and a turnover ratio 

 of 0.8 (E. Klima'*) were used to determine annual 

 production from estimated shrimp standing 

 stocks. A 69r conversion between wet weight and 

 carbon content of metazoans (G. T. Rowe'^) was 

 used to determine carbon equivalents of annual 

 production estimates. 



RESULTS 



Correlational Model 



Significant correlation coefficients identified in 

 the bivariate correlation analysis along with rela- 



**E. Klima, Director, Southeast Fisheries Center Galveston 

 Laboratory. National Marine Fisheries Service, NOAA, 4700 U 

 Street, Galveston, TX 77550, pers. commun. August 1980. 



■■^G. T. Rowe, Research Scientist, Brookhaven National 

 Laboratory. Upton, Long Island, NY 11973, pers. commun. June 

 1980. 



tionships in the data that suggested patterns in 

 trophic coupling were used to develop the model 

 illustrated in Figure 3. There was a relationship 

 between the water column fauna, in this case zoo- 

 plankton, and the sediment detritus pool as evi- 

 denced by the correlations between zooplankton 

 nickel body burdens and sediment nickel concen- 

 trations as well as several zooplankton hydrocar- 

 bon body burden variables and hydrocarbons ob- 

 served in the sediment (Figure 3). The analysis 

 further indicated that primary producer biomass, 

 represented by bottom water chlorophyll a con- 

 centrations, was related to density changes in 

 benthic macroinfauna, potentially through the de- 

 tritus pool (Figure 3). Relationships also existed 

 between sediment hydrocarbon concentrations 

 and bacterial density, indicating another potential 

 link through the detritus pool. 



Within the benthos, meiofaunal and macroin- 

 faunal densities were correlated to bacterial den- 

 sities, and macroinfaunal densities were corre- 

 lated with meiofaunal densities (Figure 3). The 

 constant ratio of benthic faunal densities to bac- 

 teria and not organic carbon (Figure 3) suggested 



ZOOPLANKTON 



ID 



< 



SHRIMP 



UJ 



M UD- WATER 



INTERFACE 



BENTHIC 

 MACROINFAUNA 



DENSITY 



= 0.77 

 n = 186 



SEDIMENT 



BACTERIAL 



DENSITY 



r = 0.35 



n = 36 



BENTHIC 



MEIOFAUNA 



DENSITY 



FIGURE 3.-Schematic representation of significant < P<0.01) correlation coefficients ( r) found between south Texas continental shelf 

 environmental variables measured for 1976-77. Sample size (n) is also shown for each correlation. 



741 



