Circuli that are spaced farther apart (circuli under green lines) indicate summer season. One annulus (circuli under red line) indicates one winter season. The groups of circuli that are spaced close together are the annuli. Female dolphin produce 80,000-1,000,000 eggs at each spawning and spawn twice (perhaps as many as three times) per year. Circuli are the fine dark lines (thin arrows). Males begin to mature at a slightly larger size. Female dolphin begin to mature at 350 mm fork length, and all are mature by 550 mm. Changes in the gonads through the year indicated that the spawning season in the Florida Current extends from November through July and is at its peak in March. Reproduction was studied by gross observation of the gonads, measurements of egg diameters, and counts of maturing eggs. Male dolphin longer than about 450 mm were heavier than females of the same length. Maximum life span is probably about four years. Clarity of annuli on otolith sections viewed with the OID was generally greater than. The replacements lack circuli and annuli in the regenerated portion, so they are useless for age determin. Fish and Wildlife Service, Great Plains Fish and Wildlife. A male dolphin in the reef tank of the Miami Seaquarium, Miami, Florida, grew from about 0.5 kg (one lb.) to 16.3 kg (36 lb.) in about eight months. abnormally large focus are regenerated scales. Radii cut the circuli present in their path. One older fish belonged to age-group III (1425 mm long), and another to age-group IV (1525 mm). Annuli will appear on every scale and will have breakages of circuli on both sides of the scale. These are grooves found radially, viz., they run from focus to margin of scale. Average growth was 725 mm fork length the first year and 450 mm the second year. Check marks believed to be annuli were formed from November through February. The dolphin grows rapidly throughout its life.
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