Date of Award

Spring 5-2022

Degree Type

Masters Thesis

Degree Name

Master of Science (MS)

School

Ocean Science and Engineering

Committee Chair

Eric Saillant

Committee Chair School

Ocean Science and Engineering

Committee Member 2

Reginald Blaylock

Committee Member 2 School

Ocean Science and Engineering

Committee Member 3

Frank Hernandez

Committee Member 3 School

Ocean Science and Engineering

Committee Member 4

Jim Franks

Committee Member 4 School

Ocean Science and Engineering

Abstract

The Tripletail, Lobotes surinamensis, is an emerging candidate species for U.S. marine aquaculture. This work aimed to address two bottlenecks for hatchery production of the species by developing a hormonal induction protocol to obtain fertile spawns from captive brooders and a method for sex identification of candidate brooders.

Single pairs selected among a captive-held broodstock conditioned under a natural photothermal cycle were induced with one of five treatments (n = 5 or 6 replicates per treatment). Control (no hormone) and hCG (1,100 IU.kg-1 for females, 550 IU.kg-1 for males) pairs did not spawn. Pairs treated with GnRHa slow-release implants (75 mg.kg-1 for females, 55 mg.kg-1 for males) produced 1 to 2 spawns and, on average 695,899 eggs but fertility was very low (0.58%). Administration of Domperidone at 5 or 10 mg.kg-1 in conjunction with GnRHa implants improved all metrics with best results obtained in the 10 mg.kg-1 treatment-group (65.3% fertility, 2.83 spawns following induction, over 1.5 M eggs per mating pair, and larval survival through 4 dph averaging 33.3%). Treatment with GnRHa and Domperidone a week after an initial hCG injection did not improve these results.

Plasma levels of 11-Ketotestosterone and Estradiol 17b were assayed in males and females during the spawning season using a competitive ELISA assay. Sex identification was most effective using 11-Ketotestosterone with a 1.19% error rate in cross validation of the training set. Males with low levels of this hormone in the test dataset were mis-identified with a higher rate (7.83%) and may require additional measurements.

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