6.6 KELP FOREST RESTORATION AND THE 

 CREATION OF NEW KELP FORESTS 



6.6.1 Restoration 



The declines in kelp forests around 

 sewer outfalls and during the warm water 

 years of the late 1950' s (see above) 

 stimulated numerous continuing attempts at 

 restoration. The largest project was the 

 Kelp Habitat Improvement Project under the 

 direction of W. North. Kelco Company, the 

 largest kelp harvesting company in the 

 State of California, has also endeavored 

 to increase Macrocystis abundance, parti- 

 cularly in the Point Loma forest near San 

 Diego. Most recent kelp restoration 

 activities have been by the California 

 Department of Fish and Game (Wilson and 

 McPeak 1983). 



Kelp restoration has variously in- 

 volved killing sea urchins, removing 

 possible competitors such as understory 

 kelps, transplanting adult or juvenile 

 Macrocystis , and "seeding" areas with 

 microscopic sporophytes grown in the 

 laboratory (see North 1976b for a review). 

 Some or all of these techniques have been 

 tried at various times in various areas. 

 Sea urchins have been killed by divers 

 with hammers, by chemical treatment with 

 quicklime (see Bernstein and Welsford 1982 

 for a description and discussion of this 

 technique), and by causing animals to 

 aggregate using kelp as bait and then 

 removing them with suction dredges (Wilson 

 and McPeak 1983). Quicklime produces 

 lesions in sea urchin epidermis, but also 

 causes damage to other echinoderms (North 

 1963, 1966). It is less labor intensive 

 than other urchin removal techniques 

 (Wilson and McPeak 1983). As discussed in 

 Section 2.4 and elsewhere in this profile, 

 dense stands of understory kelps such as 

 Pterygophora californica can inhibit algal 

 recruitment, "so removal of these plants 

 has also been used to increase Macrocystis 

 (Wilson and McPeak 1983). All of these 

 techniques may result in more giant kelp 

 in the area manipulated, if Macrocystis is 

 nearby to provide a source of spores, and 

 if environmental conditions are favorable 

 for giant kelp recruitment and growth. 

 Understory kelps and sea urchins are 

 natural parts of kelp forest communities, 

 and one questions whether the objective of 



some of these efforts is to restore the 

 natural giant kelp community or simply to 

 produce more Macrocystis . 



In areas where Macrocystis is rare or 

 absent, adults and juveniles have been 

 transplanted to restore populations. In 

 some cases, plants from warmer Mexican 

 waters have been used (North 1972a). As 

 adults are large, transplanting is not an 

 easy task. Adult plants are pried from 

 the bottom, towed slowly behind a boat or 

 kept covered and wet on the deck, and then 

 reattached to weights of various sorts at 

 the transplant site by threading nylon 

 rope though the holdfast and around the 

 weight (North and Neushul 1968, North 

 1976b). Juveniles are tied to suitable 

 rocks, or to the cut ends of Pterygophora 

 cal ifornica stipes (North 1976b). They 

 can also be grown on plastic rings in the 

 laboratory, and then outplanted (North 

 1976b). If either adults or juveniles 

 remain healthy, the haptera quickly grow 

 over the new substrata. The major problem 

 with transplanting large plants to areas 

 nearly devoid of vegetation has been fish 

 grazing (see Section 4.5). Often, few if 

 any plants survive, and transplanting 

 enough to possibly exceed some minimum 

 kelp biomass necessary for survival is 

 expensive, and logistically difficult. 



Microscopic sporophytes can be grown 

 in the laboratory, and then distributed 

 over the bottom where plants are desired 

 (North 1976b). This method requires that 

 suitable microsites be available for 

 attachment and growth, and that other 

 environmental conditions are favorable 

 (Figure 25). Because the proper combina- 

 tion of environmental conditions necessary 

 for kelp recruitment, even in the absence 

 of pollution, may occur infrequently at a 

 particular site (Figure 27), success rates 

 may be low. 



Most restoration attempts using these 

 methods have not had suitable controls, or 

 have not simultaneously monitored vari- 

 ables such as light and temperature, so 

 their success is difficult to evaluate. 

 Macrocystis has returned to some areas 

 where these techniques have been used, 

 particularly off Palos Verdes near Los 

 Angeles, and Point Loma near San Diego. 

 At Point Loma, the recovery began after 

 the sewer outfall was extended into deeper 



117 



