. California fish and game. Fisheries -- California; Game and game-birds -- California; Fishes -- California; Animal Population Groups; Pêches; Gibier; Poissons. ECOLOGY OF GAPER CLAM 53 V) < -I u u. o tr. UJ CD S Z 5 0 PLOT D PLOf E PLOT 4. LENGTH IN MILLIMETERS FIGURE 5. Histogram of length frequencies of recruits collected July 9 and 10, 1971, from plot D (Gunther Island), plot E (Clam Island) and plot 4 (Primary Study Area). Variability in the number of settling peaks from year to year has been recorded for other bivalves. Tegelberg (1964) "found that more than one settling peak pe
. California fish and game. Fisheries -- California; Game and game-birds -- California; Fishes -- California; Animal Population Groups; Pêches; Gibier; Poissons. ECOLOGY OF GAPER CLAM 53 V) < -I u u. o tr. UJ CD S Z 5 0 PLOT D PLOf E PLOT 4. LENGTH IN MILLIMETERS FIGURE 5. Histogram of length frequencies of recruits collected July 9 and 10, 1971, from plot D (Gunther Island), plot E (Clam Island) and plot 4 (Primary Study Area). Variability in the number of settling peaks from year to year has been recorded for other bivalves. Tegelberg (1964) "found that more than one settling peak per year occurred commonly for the razor clam, Siliqua patula, at one beach and irregularly at two other beaches in Washington. Hirschhorn (1962) also found unequal settlement dates for razor clams in Oregon. The gaper clam of the intertidal beds of Humboldt Bay is a winter spawner (Machell and DeMartini 1971). Bourne and Smith (1972a) found that laboratory reared gaper clams remain as planktonic veligers up to 3 weeks. On April 25, 1970 and 1971, recruits averaged about mm ( inch) long, and may have settled approximately 1 month earlier. Two settlement peaks were indicated for 1970, allowing for the possibility of either more than one spawning of adult bay clams or of recruiting from outside the bay. However, we presently are unaware of significant gaper clam populations outside the bay. Eecruits greater than 2 mm ( inch) long and adults rarely occur in muddy substrates indicating that recruits may select sandy substrates for settlement. Initial spatial distribution of recruits is un- known; however, by the time they reach 10 mm ( inch) long, they are highly aggregated. Kristensen (1957) found that the recruits of the cockle, Cardium ediilc, when about 1 mm ( inch) long were distributed homogeneously in a clam bed; however, specimens 2 mm ( inch) long were patchy. He attributed the change to a patchy distribution to effects of currents which carry the sma
Size: 3942px × 634px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorcaliforniadeptoffishandgame, bookauthorcaliforniafish
