Defense Date

8-12-2021

Document Type

Thesis

Degree Type

Master of Science

Degree Name

Marine Science

First Advisor

David Kerstetter, Ph.D.

Second Advisor

Daniel Fahy, Ph.D.

Third Advisor

John Carlson, Ph.D.

Keywords

Urobatis jamaicensis, von Bertalanffy, growth models, biannually reproductive, batoid

Abstract

The yellow stingray, Urobatis jamaicensis (Cuvier 1816), is a coastal species that has limited known life-history information, especially regarding their age and growth patterns. Age estimates were assigned by counting band-pairs deposited on the vertebral centrum of stingrays caught between 2003 and 2019 (n = 195). Marginal increment analysis of different size classes was used to validate age estimates, with the largest class having verified annual band deposition (ANOVA, F(9,7), P = 0.029). Age estimates ranged between females, and rates, but females attained larger sizes with the largest observed DW being 241-mm and 216-mm for females and males, respectively. Preliminary estimates suggest sexual maturity for males is reached when DW is roughly 154-mm while females indicated sexual maturity at 148-mm and first maternity at 160-mm DW. Sex-specific observed size-at-age data was fitted to five different growth models. The Akaike’s information criteria (AICc) indicated that the modified von Bertalanffy growth function fit best for sexes combined (DW¥ = 194.44-mm and k = 1.15 year-1), the VBGF2par model fit best for male data (DW¥ = 184.03-mm and k = 2.21 year-1), and the Gompertz model fit best for female data (DW¥ = 201.24-mm DW and k = 0.83 year-1). The age and growth data collected for U. jamaicensispopulations in southeast Florida will contribute to the limited life history information of this species and related batoids.

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