Facultative Auto/heterotrophs; and heterotrophic categories Bacterioplankton, 

 Microzooplankton, Hoiomucus Feeders. Meromucus Feeders in two stages. 

 Feeding and Nonteeding, Raptorial Feeders, Holograzers in Feeding and 

 Nonfeeding stages, Benthic Meroplankton both Feeding and Nonfeeding. and 

 Nektronic Meroplankton Feeding and Nonfeeding. The Benthic Submodel 

 principal categories are Microheterotrophs, Permanent and Temporary Micro- 

 fauna, Mucus, Tentaculate and Filtering Suspension Feeders, Selective and 

 Nonselective Deposit Feeders, and Raptorial Feeders. The major Organic 

 Complex compartments are Fecal Material, Organic Aggregates, Fine Particu- 

 late Organic Carbon, Pelagic Dissolved Organic Carbon. Pelagic Dissolved 

 Inorganic Carbon, Benthic Particulate Organic Carbon, in two categories. 

 Surface and Subsurface, and Benthic Dissolved Carbon, both Organic and 

 Inorganic. The principal categories of the Nekton Submodel reflect different 

 types of life history ontogenies, including trophic relationships, and patterns of 

 migration and spawning. They are defined according to feeding and excretion 

 habits and locations. The compartments and representative genera and species in 

 them are: Pelagic Planktivores (Anchoa spp., Peprilus hurt i and Polydaciylus 

 octonemus). Pelagic Carnivores (Cynoscion spp. and Trichiunis leptiirus). 

 Pelagic Omnivores ( Chloruscuinhrus chrvsurus and Loligo sp. ): the members of 

 these first three categories feed and e.xcrete mainly in the water column; 

 Demersal Carnivores (Elropus crossutiis and Purichihys porosissimus) feed 

 mainly in the water column and excrete in the benthos; Switch Feeders (Arius 

 fells. Stelllfer lanceulatus and Sienoiomus caprlnus) feed mainly in the benthos 

 and excrete into benthic detritus; and Reef Type Schoolers (Haemulon 

 macrosiomum and Luijanus ccimpt'ihunus) feed principally in the benthos 

 nocturnally and excrete in the water column diurnally. These compartments and 

 their subcompartments are interconnected by carbon flows, and they interact 

 with the ecosystem's environment by a multitude of processes, including primary 

 production, longshore transport, onshore-offshore migrations, human har- 

 vesting activities, and destructive influences of wave fronts and storms. The 

 whole ecosystem model would illustrate the importance of influences in 

 networks more strongly, but the Nekton Submodel by itself makes an adequate 

 and less overwhelming case. 



M. Craig Barber, Elizabeth F. Vetter, and Susan L. Durham formulated the 

 dietary compositions in Table I based on data drawn from R. .1. Conover'** and 

 R. M. Rogers.''^ These Table 1 diets, which represent daily fractions of carbon in 

 prey compartments transferred to predator compartments, were derived from 

 data which are basically predator compartment oriented (e.g., stomach analyses) 

 by the following procedure developed by Barber. Let f.^ be the daily food 

 (carbon) ration from compartment] to i in an n compartment system(i, j=l,...,n). 

 With X, the standing crop of predator i, the daily turnover rate of this 

 compartment is T7'= Zji, f||/x,. Turnover time T, and f,, data can be used to 

 calculate a retrospective Markov chain {f'(t)£:{X|,...,Xn}, t=0, 1,2,...}, in which 



the random variable f (t) designates the compartment x, x^ in which a unit of 



carbon resides at time t. Under two assumptions f '(t) can be manipulated to yield 

 a forward Markov chain. {f"(t)£'{X|,...,x^}, t=0, 1,2,...}. and hence donor oriented 

 food transfer rates: (1) the transition probabilities of {f(t)} must be time 

 invariant, and (2) the state space {X|....,Xn} must be such that any state x, can be 

 reached from any state x^ in a finite number of state transitions. An ergodic set of 

 states was achieved by closing the {Plankton. Nekton, Benthos, Organic 

 Complex} system. Then the {Plankton, Nekton, Benthos} subsystem could be 

 represented as in Figure 1 and Table 1 as an open system with Organic Complex 

 compartments as environment. Let a'j = f|j/x, be the fraction of predator i"s daily 

 diet that comes from donor j. The fraction a"of prey j's standing crop contributed 



104 



