164 
and because many species inhabit the estuary for all or part of their 
life cycles. Conditions (light, nutrient levels, circulation, etc.) im an 
estuary-salt marsh region are such that plants can readily capture the 
sun’s energy and store it for use by other organisms in the community. 
Estuarine regions produce about ten tons of organic matter per acre per 
year, whereas agriculture produces about one and one half to five tons 
per acre per year.’ Open ocean production is generally less than one 
half ton per acre per year. Ryther has estimated that the coastal 
regions of the world (which in his definition include a large part of the 
continental shelf, total about 10% of the ocean) support approxi- 
mately half of the ocean’s fish supply.t Much of this production is in 
ine estuarine zone. Thus a small area supports a great deal of marine 
ife. 
Many species inhabit the estuary for all of their life cycle. Others 
use the estuary for a spawning ground, a nursery, or as a means of 
passage to fresh water rivers. Table I lists the dependence of important 
sport and commercial fish on the estuarine zone. 
TABLE 1.1—ESTUARINE DEPENDENCE OF IMPORTANT SPORT AND COMMERCIAL FISH 
Type of dependence 
Biophysical region Permanent residence Passage zone Nursery zone 
SPORTS FISH 
North Atlantic_._..____.___- Croaker, Atlantic mackeral, bluefish__. Atlantic salmon, shad____ Striped bass. 
Middle Atlantic._.__._._.___ Croacker, drums, Atlantic mackeral, Shadeologayeras 4 2 Do. 
spot, bluefish. 
Chesapeake___-__-_-____-_-_- Crabs, croaker, drums, spot, bluefish______- Oe a een ee Do. 
South Atlantic.____-.______- Crabs, croaker, drums, spottedsea  —-___- dou. JIfhes Uber Do. 
trout, spot, bluefish. 
Caribbean: 222285 ise. fir Spotted sea trout, spot, bluefish___.______--_--+__L_--__+------- 
Gulf of Mexico____.-____---- Crabs, croaker, drums, spotted sea Shad! 82 st raeie a> awake, Do. 
trout, spot, bluefish. ' 
Pacific Southwest____--____- Abalone, rockfish, barracuda______+_____-__=--_-----_-=-+-+--- 
Pacific Northwest____-_.___- Abalone, rockfish__._._--.----------- Salmon (chum, coho, Pink salmon. 
king, red). 
Alaskas oe Fk 2 eS Crabs 282 ee Ree ee fe ia. fe (af ROR cae YS! So Do. 
Pacific Islands.___.______-.- Barracudas Ses ht ot EE AE IG REO, “ee ern eee 
COMMERCIAL FISH 
North Atlantic.__-.-_.__._-- Oysters, clams, croaker, flatfish____.__ Atlantic salmon, eel_____. Menhaden, lobsters. 
Middle Atlantic____.__-_________- Oe. te eee ae Ce ee Eel_____- _ Menhaden. 
Chesapeake-__-_______._-.- Oysters, clams, crabs, croaker, flatfish _____- do_ Do. 
South Atlantic_ . Oysters, crabs, croaker, flatfish_.....___-__- do_ _ Shrimp, menhaden. 
Caribbean_____ 2iBlatfis hiss seas cy 7 we ee _ Lobsters. 
Gulf of Mexico_ Shrimp, menhaden. 
Pacific Southwest 
... Oysters, crabs, croaker, flatfish___..__.-____- 
“J¢lams;-abalone: tlatfishe 422 =). sa Eh es ee eee 
Pacific Northwest__-_____ an. Oysters, abalone, crabs, flatfish_______ Salmon ee coho, Pink salmon. 
king, red). 
Alaskat\? ccies Paseo). Crabs, flatfish_._. “352 fags ee _ Tee doviet. ALOE Gt Tes Shrimp, pink salmon. 
Pacific Islands___._._-_-___- Oysters, fflattish:.2 8222 te 8 We gh eee Lobsters. 
1 From FWQA, p. 116. 
The commercial value of estuarine dependent species is large. The 
U.S. fishing industry landed $438 million of fish in 1967. Two thirds 
of the catch were estuarine dependent species. Five of the top six 
species by weight spend some part of their lives in estuarine waters 
(menhaden, crab, shrimp, salmon, flatfish). Seven of the top nine 
species by value also depend on the estuary in some manner (shrimp, 
ay che pod Mildred Teal, Life and Death of the Salt Marsh (Boston, Mass: Little Brown and Co., 1969), 
get ohn H. Ryther, ““Photosynthesis and Fish Production in the Sea,’’ Science, vol. 166, (October 3, 1969), 
p. 72. 
