Fish
Publications
Johnson, M., S. Bortone, B. Klement, and R. Shipp. 2011. Population changes and location-specific differences for otolith-derived age and growth of recreationally harvested Spotted Seatrout (Cynoscion nebulosus) from Alabama in 2007. Gulf of Mexico Science 29:13–24.
Spotted seatrout (Cynoscion nebulosus), is a nonmigratory game fish common in the Gulf of Mexico that is important in estuarine ecosystems. Population dynamics of spotted seatrout were examined using otolith-based age-and-growth models derived from observed and back-calculated length-at-age values. These data were used to identify sex-based differences and annular variation. Recent growth was quantified, using marginal increment analysis for comparisons between sexes and the two major bays in Alabama (Mobile Bay and Mississippi Sound). Sex ratios were also compared for these locations. Our results show that females were larger than males and that fish collected in Mobile Bay were larger than those from Mississippi Sound. Combined data from both bays resulted in a sex ratio that approached 1 : 1; however, examination of each bay individually showed that the Mississippi Sound had a female-biased population and that Mobile Bay had a male-biased population. Differences in observed length-at-age measurements became evident between males and females by age 2 with females typically larger than males, whereas the maximum age for males was greater. The oldest females were age 5 and the oldest males were age 8. Compared to previous estimates of trout growth in Alabama, results showed an increase in the modal length of fish and increased growth rates. Results suggest faster growth of the fish in the current population and decreased harvest of larger fish compared to historic estimates. This may be indicative of ecosystem-wide changes in spotted seatrout populations and highlights the need to closely monitor this population.
Bortone, S.A. 2006. A perspective of artificial reef research: the past, present, and future. Bulletin of Marine Science 78:1–8.
In a relatively short time, artificial reef researchers have established a rich and valuable archive of information from which to build future research programs. The personal interactions and dialog essential for the development of "good science" has been established and continues. Ongoing studies have increased in rigor and professionalism while building on ecological theory. Artificial reef research is becoming more sophisticated from a technical perspective, but needs to address the inherent problems in working in a "boundless" environment that often is impacted by human interference. With the incorporation of information from other disciplines, improvements are expected in overall approaches when attempting to answer several fundamental questions. To facilitate this improving trend, adequate funding resources will be essential. Concomitantly, study designs that incorporate large-scale and long-term approaches, when coupled with multi-jurisdictional cooperation, will eventually allow a full assessment of the potential benefits artificial reefs may have toward achieving fisheries management objectives.
Bortone, S.A., A.J. Martignette, and J.P. Spinelli. 2006. Spotted seatrout (Family Sciaenidae) growth as an indicator of estuarine conditions in San Carlos Bay, Florida. Florida Scientist 69(OOS2):127–139.
Life history characters of the spotted seatrout (Cynoscion nebulosus) have tremendous potential to discern trends in environmental conditions within and among estuaries. The species is widely distributed (i.e., from North Carolina to Mexico), is both commercially and recreationally important, and rarely leaves its home estuary. Thus, the estuarine conditions to which a population was subjected while growing could affect changes in its life history features such as growth. About 400 spotted seatrout were collected from April through July 2003 from the San Carlos Bay area of the southern portion of Charlotte Harbor in southwest Florida. Otolith sections were examined with enhanced imagery to facilitate recording age and annulus increments from the otolith. There was a significant relationship between otolith radius and fork length that differed between sexes. A comparison of back-calculated size at Age 1 for four year classes (1999–2002) indicated that there were significant differences in growth between year classes. Initial time-series analysis indicated the potential effects of seagrass density and salinity on fish growth. Salinity conditions are artificially manipulated in this estuary and this action may be responsible for the differences in growth rates observed for both males and females among year classes.
To protect and care for Southwest Florida's coastal ecosystems.