Reish (1963), in his studies of 

 Alamitos Bay Marina, discovered a drop 

 in the benthic population in the basin 

 area approximately one year after con- 

 struction. No significant drop occurred 

 in the channel area. Reish (1963) sug- 

 gested that the decrease in the popula- 

 tion was a result of limited water circu- 

 lation. In this case the dissolved oxy- 

 gen content decreased and the gray 

 odorless substrate became black and 

 had a strong sulfide odor. Carlisle 

 (1977) explains a problem where har- 

 bors act as water traps creating condi- 

 tions suitable for dinoflagellate blooms. 

 These blooms die off, causing a decrease 

 in the dissolved oxygen levels resulting 

 in massive fish kills "which in turn per- 

 petuate the lack of oxygen. 



Water quality in a harbor is fur- 

 ther affected by boating activities. Pe- 

 troleum products are released into the 

 water from boats and trailers. The clar- 

 ity of the water is influenced by boat 

 traffic to varying degrees, depending 

 on the depth of the water (Bowerman 

 and Chen 1971). A study of Marina Del 

 Ray by Bowerman and Chen (1971)show- 

 ed that the shallower basins were gen- 

 erally not as clear as the deeper mid- 

 channel water. The increased cloudiness 

 can reduce light penetration, resulting 

 in reduced photosynthesis and oxygen 

 production. 



General increased usage can cause 

 adverse effects in the area. Potential 

 pollution problems exist from oil spills, 

 sewage disposal, land runoff, and ero- 

 sion (U.S. Department of Commerce 

 1976). Copper contamination can result 

 from protective paints on boats, floats, 

 and other marina structures or by the 

 treatment of hulls with copper-based 

 toxicants. These factors, in addition to 

 a lack of water circulation, can create 

 serious water quality problems. Accord- 

 ing to Clark (1974) the aquatic biota is 

 endangered by the inability of harbor 

 waters to rid themselves of the "marina- 

 source contaminants." Noise and air 

 pollution may also disturb the aquatic 

 and terrestrial inhabitants of the area. 



There is some question on the ad- 

 vantages and disadvantages of small 

 craft harbors in relation to fish. Where 

 harbors cause migrating fry to move 



into deep water, predation is increased 

 (Rickey 1971). The loss of shallow wa- 

 ter areas for spawning and for nursery 

 areas is of concern. However, according 

 to Stephens (1977) harbors produce a 

 "modified bay-like environment" condu- 

 cive to fish habitation. The breakwa- 

 ters, groins, jetties, and riprap are 

 all considered to provide increased hab- 

 itat for fish or for the organisms on 

 which they feed. Another possible advan- 

 tage is that harbor waters tend to be 

 warmer and may be preferred by the juve- 

 nile fish (Stephens 1977). Heiser and 

 Finn (1970) observed that pink and chum 

 salmon fry concentrated inside marinas. 

 They also noted that the fry were more 

 adaptable to this type of environment 

 and more resistant to predation than was 

 previously thought. Rather than school- 

 ing and moving to shallower water when 

 disturbed in undeveloped beach areas, 

 the fry were observed to dive 3 to 5 ft 

 (C.9 to 1.5 m) and swim away. When the 

 fish moved into deeper water to swim 

 around breakwaters or bulkheads, preda- 

 tion was increased. However, Heiser and 

 Finn (1970) state that predation may 

 have been less within the marina than in 

 smaller natural beach areas due to the 

 increased "activities which tended to 

 discourage birds and larger fish species 

 from attacking the salmon juveniles." 



Cumulative effects. Cumulative ef- 

 fects of small craft harbors constructed 

 in wetland areas may include the elimi- 

 nation of such areas as productive habi- 

 tats. The impact on the environment 

 increases as the area covered by these 

 facilities increases. Decreased water 

 quality and increased human activity 

 over a large area is not conducive to 

 natural productivity. 



Structural and Nonstructural 

 Alternatives 



Structural alternatives to the 

 small craft harbor can best be under- 

 stood by evaluating the individual com- 

 ponents making up the harbor. A harbor 

 can consist of breakwaters, bulkheads, 

 piers, ramps, revetments, and other 

 structures, and each of these components 

 has potential alternatives described 

 elsewhere in this report. There are, 

 however, alternatives to the entire har- 

 bor which are described below. 



98 



