FISH CONTROL 



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of the fish enemies of the salt marsh mosquito in the north, beyond 

 the range of Gambusia. 



This fish attains a length of from 4 to 6 inches, and is charac- 

 terized by banded markings, rounded fins, a short head and 

 obtuse snout, a projecting lower jaw, a convex tail and a very 

 flat area between the eyes. While the killifish has the faculty 

 of changing its color somewhat to approach its prey or to escape 



Fig. 120. — Fundulus heteroclitus, female. 



an enemy, the general color of the female is olivaceous on top 

 with a lighter belly, and the male is darkish green on top with a 

 yellowish belly. Both male and female generally have numerous 

 spots and markings. 



This fish is oviparous. The eggs are very resistant and, as 

 soon as they are laid, they sink to the bottom in the mud, which 



Fig. 121. — Eundulus heteroclitus, male. 



protects them. They hatch out in about 21 days of warm 

 weather. The young fish hatches with a yolk sac, which soon 

 disappears, after which it feeds on minute plankton. 



Many of the eggs are eaten by its own kind. Other enemies of 

 the killifish are weakfish, dogfish, smelt, striped bass, etc. Man 

 frequently uses the young as bait. 



The spring migration begins as soon as the weather becomes 

 warm, and gravid females are found shortly thereafter. The 



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