S Gregory Tolley

Florida Gulf Coast University | FGCU · The Water School

Few estuaries remain unaffected by water management and altered freshwater deliveries. The Caloosahatchee River Estuary is a perfect case study for assessing the impact of altered hydrology on natural oyster reef (Crassostrea virginica) populations. The watershed has been highly modified and greatly enlarged by an artificial connection to Lake Okee...

The foundation of food web analysis is a solid understanding of predator-prey associations. Traditional dietary studies of fishes have been by stomach content analysis. However, these methods are not applicable to Critically Endangered species such as the smalltooth sawfish (Pristis pectinata). Previous research using the combination of stable isot...

Abstract—Juvenile smalltooth sawfish (Pristis pectinata) were monitored in the Peace River, Florida. A series of 37 acoustic receivers was used throughout the river, 9 of which were time synchronized. In 2016, 20 individuals were tagged and tracked from 27 May through 26 October. Most juveniles resided along the northern shoreline during the day, a...

Habitat use and movements of juvenile ( < 3 yr old) Critically Endangered smalltooth sawfish Pristis pectinata were studied in the Peace River nursery in southwest Florida to estimate the size of a known nursery hotspot (high-use area). A total of 23 smalltooth sawfish were tagged during the peak recruitment period of April and May 2014 and tracked...

Oyster reefs provide structural habitat for resident crabs and fishes, most of which have planktonic larvae that are dependent upon transport/retention processes for successful settlement. High rates of freshwater inflow have the potential to disrupt these processes, creating spatial gaps between larval distribution and settlement habitat. To inves...

Oyster reefs provide structural habitat for resident crabs and fishes, the planktonic larvae of which rely on estuarine transport/retention mechanisms to ensure settlement and subsequent recruitment to reefs. During periods of high freshwater inflow, larvae can be advected downstream and flushed out onto the continental shelf, resulting in an appar...

Planktonic larvae of resident, oyster reef-associated decapods and fishes are subject to variable transport and retention whenever estuarine circulation is altered by freshwater inflow. Because freshwater inflow has the potential to advect larvae either toward or away from oyster reef settlement habitats, we compared the monthly distributions and a...

The hydrozoan Eutima sp. is an inquiline symbiont known to infest the gills of the eastern oyster Crassostrea virginica (Gmelin, 1791) in Florida waters. Although it is unclear whether Eutima sp. polyps impact oyster fitness, access to bivalve hosts plays a role in sustaining Eutima sp. populations within estuaries. In addition, reduced salinities...

The hydrology and watershed of the Caloosahatchee River and Estuary located on the southwest coast of Florida has been altered since the 1880’s. The river has also been straightened, deepened and three water control structures have been added. The last, Structure S-79, was completed in 1966 to act, in part, as a salinity barrier. These alterations...

Peroxiredoxins (Prxs) are a family of ubiquitous proteins that help minimize the harmful effects of oxidative stress by catalyzing the reduction of hydrogen peroxide (H2O2) and organic hydroperoxides to less harmful forms. A full-length cDNA corresponding to a 2-Cys Prx gene was isolated from the flatback mud crab Eurypanopeus depressus and designa...

The Comprehensive Everglades Restoration Plan (CERP) attempts to restore hydrology in the Northern and Southern Estuaries of Florida. Reefs of the Eastern oyster Crassostrea virginica are a dominant feature of the estuaries along the Southwest Florida coast. Oysters are benthic, sessile, filter-feeding organisms that provide ecosystem services by f...

Hemolymph osmolality changes following exposure to abrupt salinity change in the range of 5–40 ppt (T = 26C, full air saturation) and upon exposure to air (T = 23C, r.h. = 30%) were investigated in the flatback mud crab Eurypanopeus depressus (Smith, 1869), a dominant species on oyster reefs in Southwest Florida. During salinity trials, hemolymph o...

To measure the effect of salinity on estuarine communities, spatial and temporal variations in population distribution were investigated in the flatback mud crab Eurpanopeus depressus (Smith, 1869), a dominant species on oyster reefs in Southwest Florida. Eurypanopeus depressus were collected using lift nets (1 m2) deployed at three morphologically...

The importance of restoring filter-feeders, such as the Eastern oyster Crassostrea virginica, to mitigate the effects of eutrophication (e.g. in Chesapeake Bay) is currently under debate. The argument that bivalve molluscs alone cannot control phytoplankton blooms and reduce hypoxia oversimplifies a more complex issue, namely that ecosystem enginee...

When assessing oyster-reef habitat in estuaries it is important to understand the influence of salinity on the spatial and temporal variability of associated organisms. How comparable is community structure among stations located at different points along the salinity gradients of estuaries or among tidal tributaries that experience different l...

This study was conducted to examine the potential influence of salinity, a proxy for freshwater inflow, on the prevalence of the castrator parasite Loxothylacus panopaei on saltmarsh mud crabs Panopeus obesus on SW Florida oyster reefs. Spatial and seasonal patterns of the presence of potential host crabs and the prevalence of the parasite were ass...

To assess the role of live oysters in providing habitat, community metrics of resident fishes and decapod crustaceans were compared among 3 habitat treatments: live oyster clusters; cleaned, articulated shell; and sand bottom. Samping was conducted during three seasonally wet and three seasonally dry months using 1-m2 lift nets deployed on an inter...

To gauge the influence of salinity on the habitat value of oyster reefs, spatial and seasonal patterns of the presence of reef-resident fishes and decapods were assessed in the Caloosahatchee, Estero, and Faka Union estuaries of Southwest Florida. Lift nets (1 m2) containing 5 L of oyster clusters were deployed on intertidal reefs at three sites al...

Studies of oysters, Crassostrea virginica, collected from 10 sites in the Caloosahatchee River and Estuary, Florida, revealed a varied parasite and symbiotic faunae that have never been reported in this area. Organisms observed included ovacystis virus infecting gametes at four sites (prevalence <1%), ciliate protozoans Ancistrocoma sp. in the gut...

Book Review

We have developed an exercise for the geoscience classroom that uses the LAVA lamp as an analogy to introduce general education undergraduate students to oceanography. The exercise provides a link between previously learned (from their secondary educational experience) and new knowledge by placing basic principles of science within an oceanographic...

The effects of extreme freshwater events on Perkinsus marinus–Crassostrea virginica interactions remain unexplored. The effects of freshwater events on P. marinus infection in C. virginica and oyster survival were therefore examined in controlled laboratory experiments and a field study. For the laboratory experiments, oysters were collected in spr...

Little research has been devoted to the investigation of swimming energetics and performance in lie-in-wait predators. This study evaluated activity metabolism and swimming performance in juvenile snook, Centropomus undecimalis, a lie-in-wait predator, by determining oxygen uptake in a tunnel respirometer. Compared to previously reported results fo...

Interdisciplinary teaching, research experience, and active, collaborative strategies have all been identified as practices highly favorable to the learning process. By using the university campus as the focus for the study of the entire watershed within which it is situated, the Campus Ecosystem Model presents a context for incorporating these ped...

An interdisciplinary course titled Issues in Ecology and Environment was developed and taught by an anthropologist and an oceanographer at Florida Gulf Coast University beginning spring 1998. Focusing on cognate interdisciplinary competencies rather than diverging disciplinary content, this collaboration also yielded working definitions of several...

Abundances of copepod nauplii, copepodite/adult copepods, and the larvae of iteroparous anchovies (primarily the bay anchovy Anchoa mltchllli) were monitored in Tampa Bay, Florida (USA) at 2 wk intervals for 2 yr. All possible pairings of the 3 time-series variables yielded significant positive correlations. Nearly all (>98%) of the collected ancho...

Seven species of whale fishes, belonging to three families, were collected by assorted research vessels from various locations within the Gulf of Mexico from 1965 through 1987. This material, which includes two species new to the region, raises the recorded number of cetomimoid species in the Gulf to eight. A significant positive correlation was fo...

Distribution, growth, and mortality of larval spotted seatrout, Cynoscion nebulosus. were compared between the Naples Bay and Fakahatchee Bay areas of southwestern Florida during the period of July 1983 through January 1985. Back-calculated spawning dates ranged from mid-March through mid-October, with major peaks occurring during the warmer months...