Parr, R.T., C.A. Jennings, N.D. Denslow, K.J. Kroll, and R.B. Bringolf. 2016. Evaluation of reproductive status in Tripletail by traditional and non-lethal approaches. Marine and Coastal Fisheries: Dynamics, Management, and Ecosystem Science:8(1):16-22.
Abstract
Reproductive biology information is an important tool for fishery management actions such as identification of spawning areas and development of protective size limits, bag limits and seasons. Such information for management of tripletail (Lobotes surinamensis) is currently limited, particularly in the western Atlantic Ocean, as information regarding the reproductive biology of this species is sparse in the published literature. To this end, we determined the reproductive status of tripletail and compared results of a non-lethal sampling method, plasma vitellogenin (VTG) analysis, to traditional (lethal) methods: gonadosomatic index (GSI) and gonad histology. A total of 223 (122 males and 101 females) tripletail were sampled over two years near Jekyll Island, Georgia (USA). Gonad histology indicated 107 (94%) of the male tripletail were in the spawning-capable reproductive phase. Female tripletail were found in all reproductive phases, but only 9 (8.9%) were in the spawning-capable phase. Plasma VTG was strongly related to GSI in females (R2 = 0.832, n= 77) and female GSI differed significantly among reproductive phases (p <0.0001). The estimated length at which 50% (L50) of female tripletail reached maturity was 463 mm; however, the L50 for male tripletail could not be determined because of the lack of immature fish within the study sample. Our study provides valuable information for management of tripletail and indicates that a non-lethal approach (plasma VTG) may be useful for differentiating developing and spawning-capable females from males and from females in other reproductive phases.