196 lidihlc MoHiisca of the Ore 1:^0 11 L'oast 



each month thniii^hout the year. In the Siuslaw River the 

 species spawns (Un'inL; the kite snniiner the period clusini;- ahnnt 

 the niidtUe of Septemher. h'nll\- formed sjjermatozoa may he 

 detected ahont the first of Jnly while nsnaUy hy tlie 1 5tli of 

 Septemher the Ixxhes of hoth males and females are in a s]jent 

 condition. Later in the }ear and during- the winter and s])rin<4 

 months Nonnj^-. immatnre ova and spermatocytes in varions stai^es 

 of development are present. The heii;ht of the spawning season 

 in this locality seems to be the latter part of Augnst and the first 

 week in Septemlier ( Fignre \'. 10. 11. 12). 



1*)V the latter part of November young" clams from 10 to 

 25 mm. in length may be found in the beds just under the sur- 

 face of the mud beneath patches of eel grass. The eel grass 

 serves as a hold-fast for the embryonic clams which cling to it 

 by their byssus threads until they are of sufficient size to dig into 

 the soft mud. 



Kellogg" reports that the breeding season of Mya arenaria in 

 Ihizzards Bay extends from the latter jiart of May to the early 

 part of August, reaching its height in late June or early July. 

 Local conditions probably determine the spawning period of this 

 species in each locality. 



The rapid growth of ]Mya arenaria. especiall}- when young, 

 and the demonstration of the success of replanting depleted areas 

 make this species a suitable one for experiments in clam culture. 

 Rapidity of growth depends, naturally, upon a number of condi- 

 tions such as the character of the bottom, currents, exposure 

 between tides, amount of food. etc. It has been shown by Kel- 

 logg, as cited above, that clams from 1 to i^ in. long when 

 planted may reach a fair marketable size in one year's time. 



Nightingale' has pointed out that clam culture will insure a 

 uniform sup])ly and restore de])leted beds tD their former pro- 

 ductivity, and that clams artificiall}- i)lanted under favorable con- 

 ditions will mature in from 9 to 14 months while in natural beds 

 from 2 to 3 years may be recpiired. 



Measures should be taken to replant portions of the beds of 



" KelloRK. •!■ I'- Conditions troveriiii't; existence and f.'i(i\vtli of tlie soft-sliell clam 

 (Mya arenaria). I'art 2U. Report of tlie I'. S. Coiiiiiiissioner of Fislieries for vear l!Mi:;. 

 pp. 195-224. 



"Nightingale. H. W. Conceriiiiig tlie Mortality of the Soft Clams at Essex, Mass. 

 Kconoiiiic Circular No. Id, 1'. s. Bureau of Fislieries. April S, lyi.'i. 

 f-'Ol 



