. Bulletin. Science; Natural history; Natural history. RESEARCH NOTES 165 S ^ > O 18 18 I. l» 16 > 18 JAN I FEB I MAR ' APR ' JUN ' JUL ' AUG ' SEP ' OCT ' NOV ' DEC MONTH Fig. 1. Seasonal gonosomatic indices for Citharichthys stigmaeus. Vertical line = range; horizontal line = mean; rectangle = 95% confidence interval. Sample size above each month. its original volume (Wallace and Selman 1981) making these structures readily identifiable. The presence in ovaries of mature and/or hydrated eggs (upcoming spawning) and vitellogenic eggs with yolk deposition
. Bulletin. Science; Natural history; Natural history. RESEARCH NOTES 165 S ^ > O 18 18 I. l» 16 > 18 JAN I FEB I MAR ' APR ' JUN ' JUL ' AUG ' SEP ' OCT ' NOV ' DEC MONTH Fig. 1. Seasonal gonosomatic indices for Citharichthys stigmaeus. Vertical line = range; horizontal line = mean; rectangle = 95% confidence interval. Sample size above each month. its original volume (Wallace and Selman 1981) making these structures readily identifiable. The presence in ovaries of mature and/or hydrated eggs (upcoming spawning) and vitellogenic eggs with yolk deposition in progress for a subsequent spawning indicate C. stigmaeus is a multiple spawning fish. The smallest fish in spawning condition measured 59 mm standard length. There was a significant {P < .05) decrease in gonosomatic indices in autumn even though the majority of the population was in spawning condition. Our findings of March-October spawning contrast with Ford (1965) who found ripe females to occur during a shorter period (April-September). These observations may indicate year to year variation in duration of the spawning period. On the other hand, Ford's (1965) females were collected at shallower depths (5-30 m) than our samples. Consequently, these variations in duration of the spawning period may have resulted from exposure to different depth related water temper- atures. Our data have shown C. stigmaeus to have a prolonged spawning period that approximates eight months (March-October). This extended spawning period appears to be intermediate between the two types of spawning periods seen in California flatfishes. The first type is year-round spawning which occurs in two species. These fishes are Pleuronichthys verticalis in which spawning was described by Goldberg (1982a) and Glyptocephalus zachirus which Frey (1971) studied. Other flatfish species, in contrast, have shorter spawning periods with a tendency toward winter spawning. Fitch and Lavenberg (1971) reported t
Size: 910px × 2746px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, booksubjectnaturalhistory, booksubjectscience
