Degree Granting Department
Joseph J. Torres, Ph.D.
Life history, Protogynous hermaphrodite, Florida, Otoliths, Fishery
A total of 1814 Calamus proridens ranging from 76 mm - 361mm fork length (FL) were collected and processed along the central and northwest coasts of Florida between 2000 and 2007 to determine size, sex, age, and reproductive condition. Females ranged from 76-297 mm FL (mean FL=156 mm, n=1420), males ranged from 141-361 mm FL (mean FL=244 mm, n=297), and transitionals ranged from 131-307 mm FL (mean FL=207 mm, n=42). Sex ratios sorted by length class, age, and overall were significantly different from the 1:1 ratio for gonochoristic species (P is less than 0.0001). Sagittal otoliths (sectioned and whole) from 1438 C. proridens were used to determine age. Marginal increment analysis suggested that a single annulus is formed each year in the spring. Ages ranged from 0 to 10 years with 88% of the fish being between 0 and 4 years. Females ranged in age between 0 and 6 years, while males ranged between 1 and 10 years. Growth was rapid in the first two years and then began to slow down. The von Bertalanffy growth model fitted to all observed data was L[subscript (t)]=306[1-e[superscript -0.254(t+1.69)]]. The data were further broken down into central and southern strata and the von Bertalanffy growth model showed that fish in the central region grow larger than those in the southern region. Histological analysis confirmed that C. proridens are protogynous hermaphrodites with delimited type gonads. Estimates indicated that 50% of the females in the sample had transitioned into males by age 4 and a FL of 231 mm. Calamus proridens mature at a small size; 50% of the samples were mature by 132 mm and within the first year. The samples obtained indicated that the peak spawning season is in the spring. The presence of hydrated oocytes and post ovulatory follicles in the same ovary suggests that they are multiple spawners.
Scholar Commons Citation
Tyler-Jedlund, Amanda J., "Age, growth, and reproduction of Calamus proridens, the littlehead porgy, from the northeast gulf of Mexico" (2009). Graduate Theses and Dissertations.