The Atlantic cod, a pelagic open-water spawner, can produce up to 9 million 

 eggs per female per season. The females provide little or no care after the 

 eggs are released in the vicinity of spawning males. This is true of most 

 marine spawners. Other fish species that provide little or no care to eggs or 

 young are the carp, chain pickerel, golden shiner, whitefish, lake trout, 

 suckers, yellow perch, and the alewife. There are a number of fishes (e.g., 

 sea lamprey, salmon, trout, and fallfish) which build nests for the eggs but 

 desert them soon after spawning. In contrast, the sticklebacks, sunfish, 

 bass, brown bullhead, slimy sculpin, and fathead minnow make elaborate nests 

 and provide parental care to the developing young for several days or weeks. 

 The usual number of eggs for the sticklebacks ranges from 20 to 100 (Clayton 

 et al. 1976). 



Redfish and northern pipefish provide even more protection to eggs. Their 

 eggs are protected in the oviduct or brood pouch. The young are born in a 

 more advanced stage of development. In general, fishes that utilize the 

 rivers, lakes, and estuaries for spawning are generally less fecund than 

 marine spawners and give a higher degree of parental care. 



Spawning Habits 



Reproductive habits of the fishes of coastal Maine are summarized in table 11- 

 3. The spawning season for marine fishes is well distributed throughout the 

 year with notable peaks in mid-winter (primarily resident fish) and summer 

 (primarily summer migrants). 



Of the 16 summer migrant species, 4 are known to spawn in coastal Maine or its 

 waters offshore (silver, red, and white hake, and blueback herring), 2 are 

 noted as historically common anadromous fishes (American shad and striped 

 bass) and the others do not spawn in coastal Maine. 



Spawning activities generally commence earlier in western than in eastern 

 Maine (Bigelow and Schroeder 1953). Among estuarine and freshwater fishes, 

 spawning activity is heaviest from May through July. Exceptions are salmon, 

 whitefish, and trout, which spawn in late fall (October and November, 

 principally). Data on preferred water temperature for spawning in Maine are 

 lacking for many freshwater and marine species, including some very common 

 marine fishes (e.g., sculpins, skates, hakes, sticklebacks, sea snails, sand 

 lance, eel, sea raven, smooth flounder, and rock gunnel). 



Eggs spawned externally by fishes are either planktonic (pelagic) or demersal 

 (table 11-3). Planktonic eggs are buoyant, have a specific gravity about 

 equal to that of fresh water, and usually float freely in the water column. 

 Most marine fishes, such as the Atlantic cod, silver hake, yellowtail 

 flounder, and American plaice produce planktonic eggs. Egg survival is 

 sometimes affected by currents, oil slicks, and other surface disturbances. 

 Most estuarine and freshwater spawners lay demersal eggs, which are relatively 

 heavy, usually adhesive, and sink to the bottom or adhere to submerged 

 substrates. These demersal eggs are particularly vulnerable to water level 

 changes, local water quality conditions, and smothering by sediments or other 

 solids. The large expanse of relatively shallow, protected waters (marine and 

 estuarine subtidal) in coastal Maine provides suitable and abundant habitat 

 for the spawning of many demersal egg-bearing fishes (i.e., sculpins, winter 

 flounder, rock gunnel, tomcod, and skates). 



11-16 



