Graduation Year
2013
Document Type
Thesis
Degree
M.S.
Degree Granting Department
Marine Science
Major Professor
Ernst B. Peebles
Keywords
cold kill, condition, reproduction, skipped spawning, snook, spawning
Abstract
Common snook, Centropomus undecimalis, is a popular game fish species that occurs throughout central and southern Florida, yet many questions remain unanswered regarding their reproductive strategies, including estimates of fecundity with relation to size, age, and condition of the female. These relationships are critical to improving stock assessments and fundamental to estimating spawning potential ratio, the measure by which snook are managed. Spawning snook were collected from a known spawning site, Rattlesnake Key, Tampa Bay, Florida, during three consecutive spawning seasons (2009-2011) and batch fecundity for snook was reported for the first time. Of the 43 females suitable for fecundity analysis, batch fecundity was highly variably and ranged from 258,913 to 2,663,737 eggs. The mean batch fecundity was (984,689 eggs/batch, median = 781,330 eggs/batch) and the mean relative fecundity was 465 eggs/gram body weight (median = 402 eggs/gram body weight). Average batch fecundity did not vary by collection year, despite a severe cold event in the winter of 2010, which killed about 25% of the spawning population. However, analysis of proximate composition indicated that liver lipid percent was significantly reduced in 2010, likely due to reduced prey availability, increased energetic expenditures, or both, while enduring and recovering from cold exposure. A significant positive relationship in 2009 between batch fecundity and condition was reported that entirely disappeared in 2010. Additionally, in a preliminary investigation, we detected sub-population differences between known-spawning `bay fish' and `river fish' using barium as an indicator of freshwater habitat usage via otolith microchemistry. Our results are directly relevant to enhancing stock assessments and indicated that reproductive strategies of snook are both complicated and robust. Future research should further investigate reproductive strategies (e.g. skipped spawning) and possible sub-population life history, as both can have significant impacts on stock assessment models.
Scholar Commons Citation
Hayslip, Catherine Michelle Bruger, "Investigation of Condition Effects on Batch Fecundity of the Common Snook, Centropomus undecimalis, in Tampa Bay, Florida" (2013). USF Tampa Graduate Theses and Dissertations.
https://digitalcommons.usf.edu/etd/4902
