lakes in the southwestern region of the coastal zone are more productive than 

 other areas of the coastal zone. Unfortunately, no data are available for 

 regions 1 and 6. 



The coastal zone lakes support anadromous, catadrotnous , and resident sport 

 fish species. The most widespread and common species of warm-water sport and 

 pan fishes (excluding sunfishes) in these lakes are yellow perch, chain 

 pickerel and smallmouth bass. Brook trout and rainbow smelt are the most 

 common coldwater game and pan fishes. The fisheries in coastal zone lakes 

 (n=59) have been evaluated by Cooper (1939 and 1942) and Fuller and Cooper 

 (1946). The fisheries at 151 of the coastal zone lakes were appraised in the 

 1970s (Spencer and Hutchinson 1974a, b, c, and d; Hutchinson 1977a, b, and c; 

 and Hutchinson and Spencer 1975a, b, c, and d). Data organized by individual 

 lakes are given in appendix table 3 and summarized in table 7-6. The 

 freshwater fishery of the coastal zone is a mix of coldwater and warmwater 

 fisheries. Fisheries differ from region to region. Regions 1 to 4 contain 

 mostly warmwater fisheries, and the percentages of lakes with coldwater 

 fisheries in these regions increase from southwest to northeast. In region 5, 

 coldwater fisheries predominate but warmwater fisheries remain important. The 

 fishery in region 6 is mixed, although data on it are sparse. 



Coastal zone lakes serve as breeding and feeding areas for a number of 

 waterbirds (e.g., loons), waterfowl (e.g., mergansers, black ducks, wood 

 ducks), and raptors (e.g., bald eagles, ospreys). Information on these groups 

 of species is presented in chapter 14, "Waterbirds," chapter 15, "Waterfowl," 

 and chapter 16, "Terrestrial Birds." 



ENERGY FLOW AND FOOD WEBS 



Trophic Structure, Energy Flows, and Budgets 



The energy entering a lake is direct-solar (light) and indirect-solar (heat 

 from substrate, from atmosphere, and from entering streams). Most of this 

 energy (including about 99% of the direct energy) is consumed by heating the 

 water. Only a minute percentage (<1%) of the light is used by the 

 phytoplankton in photosynthesis. A slightly higher percentage may be used in 

 the shallow parts of the littoral zone, due to the presence of attached plant 

 communities. A diagram of the energy flow through the biota of the pelagial 

 part of a large, deep lake is given in figure 7-5. A general, but less 

 complete, diagram of a Russian lake is given in figure 7-6. These 

 relationships have not been studied in any lakes in Maine. Allochthonous 

 inputs (from outside the lake) of organic detritus to the food web of small 

 lakes are substantial. However, in a typical medium-to large-size mesotrophic 

 or oligotrophic Maine lake (figure 7-5) it is doubtful that the allochthonous 

 detritus chain would be as important or that the Protozoa and Asplanchna would 

 appear as prominently as they do in figure 7-6. 



7-24 



