fluctuations. (For further discussion of this subject, see Genetics Committee 1975.) As worded, 

 both Acts allow, and appear to intend, that the mariculture is to take place on an extensive basis 

 (i.e., over thousands of hectares). Both require a marsh management plan, which at the time the 

 Acts were written, normally meant use of levees, weirs, or other water-control structures. Our 

 work shows that such systems greatly reduce the number and total weight of many economically 

 important fishes and shrimps that return to the gulf, even when the area is not used for mariculture 

 (for example, see Tables 1 and 2 and Figure 5). Therefore, the Acts require management practices 

 that we have shown reduce natural fishery production and which may also tend to hasten marsh 

 loss. Even if the Acts did not require it, the mariculturist will have to use some means of 

 preventing the cultured organisms from escaping. Whether the means are levees or screens, and 

 even if used for only a portion of each year, there will be no period during which they will not 

 interfere with the movement into and out of the area by numerous species (see Figure 2). 

 Stocking of the area by wild species will be even further reduced, because the systems we studied 

 contained no such complete barriers to inward movement of small organisms. 



Because it is totally impractical to feed fish in an area of thousands of hectares, the mariculturist 

 may pen the hatchery fish into a few acres and feed them until they are better able to forage for 

 themselves. This in itself causes problems. Unless water is artificially pumped through the area, 

 decomposition of the feed and fecal matter will probably use up the oxygen in the water and result 

 in death of the organisms. But if water is pumped, the poor quality water will be moved into the 

 surrounding area and adversely affect natural production there. Once the fish are released into 

 the total mariculture area they will be feeding primarily, if not exclusively, on the organisms 

 produced there naturally. Thus, the cultured fish will be competing with and preying on the wild- 

 produced fish and shrimp that are able to get into the area. 



Both Acts contain the statement that "accurate records shall be maintained on the separation 

 of wild fish from domestic stock." Because Act 305 requires all fish used in a project to be 

 purchased from a legal stock, it prohibits the sale of wild fish by the mariculturist. However, Act 

 386 does not specifically require that fish used in a project be purchased from a legal source. Thus 

 it appears that under Act 386 wild young could be used to stock the area and could be held in the 

 area until captured by the mariculturist and sold (despite the "accurate records" statement in the 

 Act). 



At this point, we know of only three ways to attempt to maintain accurate records on the 

 separation of wild fish from domestic stock. One way is to seal off the entire area so that there 

 is no interchange of water between the mariculture area and outside waters, and then attempt to 

 kill out everything in the maricultural area. We know of no poison, however, that is this effective 

 and not illegal to use, nor do we know if these Acts can make such mass destruction legal, even 

 if there were an approved poison. Also, unless the area were again opened to water circulation, 

 the water would soon become devoid of oxygen and all the organisms in the area would die. On 

 the other hand, if water circulation is restored, then wild young will enter the area. 



The second way would be to seal off the area at a time when there would likely be very few 

 of the species to be cultured in the area. (It is doubtful if there is ever a time when one could 

 be sure there is none in the area.) The culture organisms could then be stocked in the sealed off 

 area. But, again, water circulation would have to be restored and wild organisms would enter. 



The third way would be to rear the cultured young to a size that can receive a permanent mark 

 before release into the area. Even if this is done, it leaves the problem of how to harvest the 

 cultured animals without harming the wild ones. With something large, like redfish, it might be 

 possible to capture them all and then release the unmarked ones without harming too many. But 

 with smaller and more delicate animals, such as shrimp, most of the unmarked shrimp would be 

 harmed or killed in the capture process. This is especially true since the Acts allow harvest by any 



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