1984-Crystal River, FL
I saw my first West Indian Manatee (Trichechus manatus) while completing a SCUBA check-out dive in Crystal River, FL. Manatee populations are still very low, but have remained relatively stable over the past thirty years due to a concerted effort to minimize their sources of mortality. I still enjoy seeing the local manatees that live in the canals of Long Key, FL where we stay while conducting research in the Florida Keys.
My first research organism while an undergraduate researcher at the University of Tampa was the brackish-water rotifer, Brachionus plicatilis. We studied the mating behavior of these cycloparthenogenic plankton. Here a male rotifer (smaller) is attempting to mate with a female rotifer (larger). We used different behavioral essays to identify characteristics of the mate recognition glycoprotein.
1986-Key Largo, FL
My first open water SCUBA dives were in the John Pennekamp Coral Reef State Park in Key Largo, FL. When I learned to dive, the reef was composed of nearly 35% live coral cover with big stands of elkhorn coral (Acropora palmata). Today this coral is considered an endangered species in the US and is rarely found in the Florida Keys. Much effort is underway to establish coral nurseries to help restock the Acropora population.
1987-Looe Key National Marine Sanctuary, FL
Before the establishment of the Florida Keys National Marine Sanctuary, there were a few smaller "no-take" marine protected areas in the Florida Keys. Looe Key National Marine Sanctuary was known for its high reef fish densities and diversity. Today there are many "no-take" marine protected zones throughout the FKNMS to help rebuild fish population numbers.
1988-Monterey Bay, CA
The tide pools of west coast of the US are an amazing place for marine invertebrates. One of my favorite study animals in the intertidal zone is the sea star Pisaster ochraceus. This "keystone" predator once dominated the community structure of the rocky intertidal zone by keeping mussels from excluding other sessile species from becoming established. However, a mass mortality of Pisaster has recently begun and is thought to be related to lethal pathogen.
My master's thesis at UC Berkeley studied the foraging behavior of the mantis shrimp Gonodactylus bredini. This cavity-dwelling smasher lived in the shallow seagrass beds of the Caribbean. Their superior eyesight and memory made them a challenge to design experiments designed to outwit them.
I spent a summer studying at the Hawai'i Institute of Marine Biology in Kaneohe Bay, Hawaii. The summer course was on the Behavior of Coral Reef animals. It was an amazing experience to live and study so close to protected coral patch reefs. Here a pair of Moorish Idols (Zanclus cornutus) swim in formation near the marine lab.
1991-Everglades National Park, FL
My dissertation research at Florida State University was on juvenile Caribbean spiny lobsters (Panulirus argus). In their nursery habitat of Florida Bay, early benthic juveniles (on the diver's glove) make a habitat transition from macroalgae to crevice shelters. This habitat transition is mediated by the odor of conspecifics that help to guide naïve lobsters toward crevice shelters, essential for avoiding fish predators.
1992-Florida Bay, FL
Juvenile Caribbean spiny lobsters utilize large sponges such as this loggerhead sponge (Spheciospongia vesparium) as protection from predators. Beginning in 1991, massive blue-green algal blooms began to appear in Florida Bay killing these sponges by suffocation. Thousands of hectares of sponges died in 1991, 1992, and again in 2007. In areas without large sponges, the population of juvenile lobsters are mostly gone. Efforts to restore the sponge community are underway, but hampered by ongoing algal blooms.
1993-Florida Keys National Marine Sanctuary, FL
Caribbean spiny lobsters are gregarious and aggregate in crevice shelters. Over the years we have conducted numerous experiments to understand the benefit of aggregation. Our research suggests that by following conspecific odor cues, lobsters can more easily locate suitable crevice shelters that already contain other lobsters. However, this response to conspecific odor cues has been decreasing. It is unclear whether changes in water quality, increases in disease, or intense fishing pressure has caused this decline in lobster gregariousness.
1995-Saba Marine Park, Lesser Antilles
For our honeymoon, Margaret and I visited the island of Saba and dove in one of the Caribbean's first marine protected areas. Here we see the long-spined sea urchin Diadema antillarum. Once the most abundant reef herbivore throughout the Caribbean, it nearly went extinct in 1983 due to a mass mortality caused by an unknown disease. Today, Diadema populations are still very low and their loss has been correlated with a significant increase in reef macroalgae.
1996-Lee Stocking Island, Bahamas
In this photo from a small, deserted island north of Lee Stocking Island, we see two threatened species. The small lizard in the center of the photo is the northern Bahamian rock iguana (Cyclura cychlura), and the bleached shells are from the queen conch (Strombus gigas). Both iguanas and conch have been overharvested for food and have lost of critical habitat due to human development.
1997-Yellowstone National Park, WY
When Margaret and I took our first faculty positions at Idaho State University (Pocatello, ID) and Reed College (Portland, OR), we shifted some of our research efforts toward studies of trout, mountain lions, and elk conservation. We were fortunate enough to arrive during the re-introduction of the grey wolf (Canis lupus) in Yellowstone National Park. Here we see a gray wolf (possibly 167M) from the Druid Peak pack. The wolf reintroduction to Wyoming and Idaho was so successful that this once endangered species, has now been de-listed in three western states.
1998-Yellowstone National Park, WY
My graduate student Mark Lung and I conducted a four year study of the impact of the gray wolf reintroduction on the behavior of Rocky Mountain elk (Cervus elaphus). We compared the behaviors elk in different regions of the park before and after the establishment of wolf packs. Here we see the casual behavior of a herd of elk females near the Norris Geyser Basin prior to the arrival of resident wolves. As wolves became established across the park, the elk become more wary, changed their use of the riparian habitats, resulting in increased recruitment of tree, bird and beaver populations.
1999-Yellowstone National Park, WY
The reintroduction of wolves to Yellowstone also positively influenced the population numbers of grizzly bears (Ursus horribilis). Grizzlies rely on scavenging carcasses of elk, deer, bison and moose as part of their varied diet. With an increasing number of wolves in the park, grizzlies gained access to an increased number of carcasses leading to some spectacular disputes over carcass ownership.
2000-Yellowstone National Park, WY
Many of Yellowstone's ungulates have seasonal migrations from high elevations during the summer to low elevations during the winter. As a result, communities surrounding the park are having increased conflicts with wildlife coming into contact with livestock. Ranchers worry that American bison (Bison bison) may increase the risk of disease transmission (Brucellosis) to their cattle. As a result there are efforts underway to corral or harass bison back into the park to avoid developed ranch lands.
2001-Yellowstone National Park, WY
Trumpeter swans (Cygnus buccinator) are one of the endangered bird species that have breeding populations within the greater Yellowstone Ecosystem. Widespread development throughout the intermountain west has left little habitat for these and many other high elevation western species.
2002-Yucatan Peninsula, Mexico
Margaret and her graduate student Shala Hankison conducted research on four species of sailfin mollies including Poecilia velifera. Their research found that female preference for larger body size interacted with natural selection constraints on male body size to produce a range of mating strategies within this diverse group of Mexican fishes. The native range of some of these species is now so small that the remaining populations are considered to be endangered.
2003-Florida Keys National Marine Sanctuary, FL
In the mid 1970's corals throughout the Caribbean began showing signs of a disease called black band disease. Black band is caused by a pathogenic microbial mat consortium including a blue-green alga that gives it a distinctive redish-black color. Disease outbreaks have been linked to increases in eutrophication, warming waters and higher ocean acidification.
2004-Florida Keys National Marine Sanctuary, FL
The Caribbean reef shark (Carcharhinus perezi) is the most common shark in the Caribbean but have been declining in numbers worldwide. Sharks are top predators but have a very low level of reproduction and are susceptible to overfishing. Loss of top predators can have a dramatic influence on the structure of reef communities.
2005-Florida Keys National Marine Sanctuary, FL
Hawksbill turtles (Eretmochelys imbricate) are critically endangered world wide. Human hunting and loss of nesting beaches throughout their range has made their recovery very difficult. This individual was observed in the Cheeca Rocks Special Protected area of the FKNMS.
2006-Florida Bay, FL
Purple tipped sea anemones (Condylactis gigantea) and spotted cleaner shrimps (Periclimenes yucatanicus) are prized additions to hobby aquarist reef tanks. As a result, overharvesting is likely the reason for their dramatic decline over the last two decades. Our studies found that spotted cleaner shrimp prefer to associate with purple tipped anemones over the more common corkscrew anemones (Bartholomea annulata). It remains to be seen if this shrimp species will be able to shift hosts and persist if it's preferred host is no longer available.
2007-Florida Bay, FL
The Caribbean reef octopus (Octopus briareus) is a common resident in the shallow hard bottom habitats of Florida Bay. They often compete with juvenile spiny lobsters and stone crabs for crevice shelters. Lobsters regularly avoid contact with octopuses and will quickly abandon a crevice shelter if they smell an octopus nearby.
2008-Florida Bay, FL
A unwelcome new addition to Florida Bay is the Asian paddle crab (Charybdis japonica). First documented in the Indian River Lagoon on the east coast of Florida, our team has documented the first recorded sightings for this species in the Florida Keys. It is unknown what the impact of this alien species will have on the native community of crabs in Florida Bay, but we continue to monitor its population numbers.
2008-ACE Basin National Estuarine Research Reserve, SC
The Atlantic blue crab (Calinectes sapidus) is one of the most commercially important crustacean fisheries in the US. In South Carolina, blue crab numbers have been declining over the past two decades with the greatest declines in years of severe drought. My student Kirk Parmenter and I have been studying the reason for this decline and how it might be related to the change in marsh salinity profiles from wet to dry years. Crab disease (Hematodinium) increases during drought years which may explain part of the decline in blue crabs.
As part of Margaret's research on waterfall climbing stream gobies, we had an opportunity to return to Hawaii for some field work. We took the opportunity to dive on the Kona coast of the big island where large schools of manta rays (Manta alfredi) congregate in the plankton rich waters. Manta rays are considered vulnerable world wide due to overfishing. These gentle giants are filter-feeding planktivores that must eat large quantities of krill and other macroplankton to survive.
2010-ACE Basin National Estuarine Research Reserve, SC
The American alligator (Alligator mississippiensis) populations are alive and well in South Carolina salt marshes. However, these voracious predators are showing dietary switching to feeding more on marine fishes and blue crabs. As much as 60-75% of an alligator's diet may be adult blue crabs and their predation increases during wet years when salinity levels are lowest.
2011-ACE Basin National Estuarine Research Reserve, SC
Drought also has the potential to impact the reproduction and settlement of larval blue crabs. Gravid females mate upriver in freshwater and must migrate to open ocean habitats to release their zoea larvae. After a month in the plankton, the crab postlarva (megalopa - shown here) settle out the water column into saltmarsh grass. Drought has the potential to alter the success of blue crab settlers.
2012-Florida Keys National Marine Sanctuary, FL
To better understand the factors limiting the success of corals in the Florida Keys, my graduate student Kylie Smith and I have initiated a coral growth and survival study. Coral fragments of mustard hill coral (Porites astreoides - shown above) and smooth starlet coral (Siderastera siderea) were transplanted onto seven reefs in the middle Florida Keys. Some corals were caged and others were left uncaged to measure the impact of algal competition and parrotfish grazers.
2013-Florida Keys National Marine Sanctuary, FL
Red macroalgae (Dictyota spp.) is one species that has been implicated in the recent decline of corals. This chemically defended red alga can overgrow and kill small corals when it becomes too abundant.
2014- Florida Keys National Marine Sanctuary, FL
Parrotfishes including this midnight parrotfish (Scarus coelestinus) are known to graze on both macroalgae and corals. Our study seeks to understand whether the net benefit of parrotfish grazing of macroalgae outweighs occasional grazing on the most common reef corals. Although parrotfish do take bites of corals, they show much higher preference for fleshy macroalgae or turf algae depending on their dentition.