fishery harvest from U.S coastal waters, and 

 most species contributing to this harvest are 

 dependent on estuaries during either some 

 stage of their development or their entire life. 



The major purpose of our Estuarine Pro- 

 gram is to document the dependency of fishery 

 resources on estuaries, to determine the types 

 of estuarine habitat that are most important, 

 and to assess the value of these habitats in 

 terms of production of renewable fishery 

 resources. We are nnaking additional efforts 

 to determine how fishery resources are af- 

 fected by nnodifications of the estuarine en- 

 vironnnent, how to prevent excessive damage, 

 how to restore altered areas, and how to 

 improve low-value habitats. 



During the year, we developed new sampling 

 techniques and gear for studying the behavior 

 of brown and white shrimp emigrating in the 

 Galveston Entrance. Resulting data on size 

 and time of emigration were provided to 

 State personnel and were used by them to 

 manage their shrimp fishery. Ultinnately, after 

 refinement of the sampling techniques and 

 their application, it should be possible to 

 assess the contributions of a specific estuary 

 to the population of harvestable species in the 

 Gulf of Mexico. Such information is essential 

 for establishing fishery values of estuaries. 



We also have learned that vegetation along 

 shorelines and beds of submerged plants in 

 shallow water are major nursery habitats 

 for young shrimp and many species of fish. De- 

 struction of the vegetation by bulkheading, 

 channel dredging, or spoil (from hydraulic 

 dredges) eliminates these zones as nurseries. 

 This knowledge has proven valuable in ouras- 

 sessnnent of probable effects of private con- 

 struction projects and has been responsible for 

 conserving vital habitats in Texas estuaries. 



Our first efforts to transplant and establish 

 emergent vegetation on hydraulically deposited 

 spoil in a shallow bay were partially successful. 

 We learned how to stabilize the clumps and 

 determined the most suitable water depth for 

 vigorous growth. We still do not know, how- 

 ever, how to accomplish these transplantings 

 economically over large areas. 



We have negotiated successfully with the 

 Corps of Engineers for a hydraulic model 

 testing program that will provide the informa- 

 tion we need to evaluate how their hurricane 

 protection plans will affect the hydrology of 

 Galveston Bay. Through this cooperative effort, 

 we may develop a proposal that will provide 

 hurricane protection without impairing the 

 value of the estuary for fishery resources. 



Charles R. Chapman, Program Leader 



EFFECTS OF ENGINEERING PROJECTS 



Developnnent of coastal areas to meet hun-ian 

 demands usually requires a considerable 



amount of land and water alteration and re- 

 arrangement. Consequently, deterioration or 

 destruction, or both, of estuarine habitat 

 results from construction projects involving 

 tributary control of fresh water, channel 

 dredging, filling, bulkheading, marsh drainage, 

 diking, levees, and salt-water barriers. 



Work by private interests in navigable 

 waters requires a pernnit from the U.S. Army 

 Corps of Engineers. Pursuant to the Fish 

 and Wildlife Coordination Act, the Bureau 

 of Sport Fisheries and Wildlife's Division of 

 River Basin Studies is responsible for advising 

 the Corps of possible adverse effects that 

 the proposed work might have on fish and 

 wildlife resources. Frequently, construction 

 plans must be modified to reduce or elinninate 

 dannage to natural resources. We assist per- 

 sonnel of the Division of River Basin Studies 

 in evaluating all private construction projects 

 in the coastal areas of the western Gulf of 

 Mexico. The number, type, and general location 

 of applications for private construction re- 

 viewed during the fiscal year are listed in 

 table 7. 



In addition to private construction projects, 

 we also review and evaluate Federal water-use 

 projects and occasionally ones proposed by 

 the Soil Conservation Service and Bureau of 

 Reclamation. Additionally, during fiscal year 

 1967, project personnel contributed to and 

 reviewed drafts of 42 Bureau of Sport Fisheries 

 and Wildlife Reports on private and Federal 

 construction projects. 



It is innportant that we be capable of deter- 

 mining specific effects of water-development 

 projects on fishery resources so that we can 

 recommend feasible measures for lessening 

 the severity of damage or for increasing 

 habitat quality of previously damaged areas. 

 Methods must be developed for accurately 

 predicting long-range and immediate ecolog- 

 ical changes resulting from different types 

 of construction. We also must develop meas- 

 ures for preventing damage to the estuaries 

 as well as for rehabilitating or improving 

 thenn. 



Effects of Habitat Modification 



Studies have been started to determine how 

 the estuarine biota is affected by environment 

 modifications resulting fron-i channelization, 

 hydraulic spoiling, bulkheading, and filling 

 (fig. 15). The study area includes a location 

 that is being developed for housing sites and 

 a nearby unaltered area that is being studied 

 as a control. Both areas are typical small 

 bays with about 80 hectares (200 acres) of open 

 water, beds of submerged aquatic vegetation, 

 and extensive peripheral tidal marshes. 



Biological, hydrological, and physical 

 features of both areas were assessed before 

 construction to provide a basis for comparing 

 effects during and after development. These 



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