FISHERY BULLETIN: VOL. 86, NO. 3 



algae, and epiphytes of salt marsh grasses, not from 

 Spartina detritus. Algal foods also proved to be the 

 primary source of carbon for penaeids in Georgia 

 marshes (Hughes and Sherr 1983) and in P. duora- 

 rum inhabiting seagrass beds in the Gulf of Mexico 

 (Leber 1983) where food webs have long been con- 

 sidered detritus based. The significance of algal pro- 

 duction in mangrove areas has been pointed out by 

 Rodelli et al. (1984). They concluded that both 

 mangrove and algal carbon were utilized by most 

 of animals in a Malaysian swamp, but virtually no 

 animals collected at distances >2 km from the 

 swamp contained mangrove-derived carbon. To this 

 date, there is little evidence to suggest that natant 

 species such as fishes and decapod Crustacea can 

 use detritus as a primary food source even if 

 microbially enriched (Boesch and Turner 1984). 



Localities where mangroves grow often support 

 a variety of other primary producers, and variation 

 in the relative significance of detrital and algal car- 

 bon sources may be associated with tidal amplitude 

 and flushing. Laguna Joyuda, with microtidal influ- 

 ences, appears to be fueled by algal carbon where- 

 as shrimp-producing mangrove areas in Ecuador 

 have meso- and macrotidal regimes and no apparent 

 algal growth (Zimmerman, pers. observ.). That man- 

 groves provide critical substratum and protective 

 cover for a large number of organisms is undisputed; 

 however, the assumed significance of mangrove- 

 derived detritus should be examined further. 



ACKNOWLEDGMENTS 



This research was supported by the Office of Sea 

 Grant, NOAA (Grant no. R/A-01-2), a grant from 

 the National Science Foundation (No. R-II-8610677), 

 and funding from the University of Puerto Rico to 

 the Center for Energy and Environment Research. 

 D. Corales participated in the field work, along v^ath 

 G. Owen and 1. Sanders. B. A. Buchanan identified 

 the shrimps collected and assisted in the prepara- 

 tion of figures. L. L. Cruz conducted all of the gut 

 analyses and T. Robles assisted in manuscript prep- 

 aration. W. J. Richards and B. A. Buchanan pro- 

 vided helpful criticisms of the manuscript. 



LITERATURE CITED 



Boesch, D. F., and R. E. Turner. 



1984. Dependence of fishery species on salt marshes: the role 

 of food and refuge. Estuaries 7:460-468. 

 Bray, J. R., and J. T. Curtis. 



1957. An ordination of the upland forest communities of 

 southern Wisconsin. Ecol. Monogr. 27:325-349. 



Carr, W. E. S., and C. a. Adams. 



1972. Food habits of juvenile marine fishes: evidence of the 

 cleaning habit in the leatherjack, Oligoplites saurus, and the 

 spottail pinfish, DiplodxLS holbrooki. Fish. Bull., U.S. 70: 

 1111-1120. 



Chong, V. C, AND A. Sasekumar. 



1981. Food and feeding habits of the white prawn Penaeiis 

 merguiensis. Mar. Ecol. Prog. Ser. 5, p. 185-191. 



Craig, H. 



1957. Isotopic standards for carbon and oxygen and correc- 

 tion factors for mass-spectrometric analysis of carbon diox- 

 ide. Geochim. Cosmochim. Acta 12:133-149. 



Dall, W. 



1968. Food and feeding of some Australian penaeid shrimp. 

 FAO Fish. Rep. 2:251-258. 

 Darnell, R. M. 



1958. Food habits of fishes and larger invertebrates of Lake 

 Ponchartrain, Louisiana. Publ. Inst. Mar. Sci., Univ. Texas. 

 5:353-416. 



Edwards, R. R. C. 



1978. The fishery and fisheries biology of penaeid shrimp on 

 the Pacific coast of Mexico. Oceanogr. Mar. Biol. Annu. 

 Rev., p. 145-180. 



Field, J. G., and G. McFarlane. 



1968. Numerical methods in marine ecology. I. Quantitative 

 "simUarity" analysis of rocky shore samples in False Bay, 

 South Africa. Zool. Air. 3:119-138. 

 Fry, B., R. K. Anderson, L. Entzeroth, J. L. Bird, and P. L. 

 Parker. 

 1984. '^C enrichment and oceanic food web structure in the 

 northwestern Gulf of Mexico. Contrib. Mar. Sci. 27:49-63. 

 Fry, B., R. Lutes, M. Northam, and P. L. Parker. 



1982. A '^C/'^C comparison of food webs in Caribbean 

 seagrass meadows and coral reefs. Aquat. Bot. 14:389-398. 



Fry, B., and P. L. Parker. 



1979. Animal diet in Texas seagrass meadows: d^^C evidence 

 for the importance of benthic plants. Estuarine Coastal 

 Mar. Sci. 8:499-509. 



Fry, B., and E. B. Sherr. 



1984. d^^C measurements as indicators of carbon flow in 

 marine and freshwater ecosystems. Contrib. Mar. Sci. 27: 

 13-47. 



Garcia, S. 



1974. Biologie de Penaeus duorarum notialis en Cote 

 D'lvoire, IV. Relations entre la repartition et les conditions 

 du milieu - etude des variations du sex-ratio. Doc. Sci. Cent. 

 Rech. Oceanogr. Abidjan. 5(3-4): 1-39. 



Garcl\, S., M. Lemoine, and E. Lebrun. 



1985. Seasonal and long-term variability of recruitment in 

 French Guiana shrimp fishery on Penaevs suhtilis. FAO 

 Fish. Rep. No. 327, SuppL, p. 242-250. 



Gleason, D. F. 



1986. Utilization of salt marsh plants by postlarval brown 

 shrimp: carbon assimilation rates and food preferences. 

 Mar. Ecol. Prog. Ser. 31:151-158. 



Gleason, D. F., and R. J. Zimmerman. 



1984. Herbivory potential of postlarval brown shrimp associ- 

 ated with salt marshes. J. Exp. Mar. Biol. Ecol. 84:235- 

 246. 



Hughes, E. H., and E. B. Sherr. 



1983. Subtidal food webs in a Georgia estuary: d^^C anal- 

 ysis. J. Exp. Mar. Biol. Ecol. 67:227-242. 



Laughlin, R. a. 



1982. Feeding habits of the blue crab, Callinectes sapidus 

 Rathbun, in the Apalachicola Estuary, Florida. Bull. Mar. 

 Sci. 32:807-822. 



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