White Shark (Carcharhinus carcharias). Credit: Florida Sea Grant Stock Photo
From Fear to Fascination: White Sharks in the Florida Panhandle
UF/IFAS Extension – Florida Sea Grant
By Rick O’Connor (Escambia County) and L. Scott Jackson (Bay County)
Recently, I was walking on our local Gulf fishing pier checking fishing line recycle bins. You can’t walk on a Gulf pier without looking over to possibly catch a glimpse of a sea turtle or a shark, and I was not disappointed. It was hard to tell which species of shark but it was about 6 feet in length. It swam south along the edge of the pier and then east to make a large arching circle through the emerald water, past bathers at the surf break, and back to the pier only to swim the pattern again. Onlookers from out-of-town were giggling with delight to see the animal while a couple of local fishermen tried tossing bait at it, but most ignored it and went on with their fishing.
Bob Shipp’s book, Fishes of the Gulf of Mexico, lists 29 species of shark found locally. Most are members of the requiem shark family, such as blacktips and bulls, and hammerheads. Though these sharks are certainly capable of attacking humans, their presence usually does not interrupt water activities. Divers who encounter sharks may be startled at first but rarely do they end their dive or have problems with them. Even in 2005, remembered as the “summer of the shark attack”, few people stopped diving or surfing. Individuals have become educated regarding shark behavior and are not as startled when they see one. However, in 2015 there were several encounters with White Sharks.
Sightings in the Gulf of Mexico are rare but usually occur in the cooler months. Is the increased interaction with White Sharks unusual or something to worry about?
Burgess assured me that White Sharks do occur in the Gulf of Mexico usually during cooler months and are transients, as opposed to residents. Their movement in and out of the Gulf is temperature driven. As late spring Gulf waters continue to warm into early summer, sighting a White Shark is less likely to occur. According to Burgess, White Sharks use deep water when traveling but prefer shallow water when hunting fish, turtles, and marine mammals. So, inshore encounters especially in cooler months would not be unusual.
Why is there a sudden increase in the numbers of encounters?
One part of the answer lies with the increased number of White Sharks. Conservation of sharks has been effective. Additionally, with the passing of the Marine Mammal Protection Act, there are more marine mammals, thus an increase in their predators, White Sharks. The other part is the number of humans visiting the northern Gulf has increased. There are more more visitors to marine waters, especially since the Deepwater Horizon oil spill. Everyone has a camera. Beachgoers, Swimmers, Divers, and Anglers all have improved technology to record their adventures.
Is Northwest Florida a “hot spot” for White Sharks? Burgess indicated that the northern Gulf of Mexico is more productive than the peninsular Florida due to the number of nutrient rich rivers in the region. Seeing more White Sharks here would not be any more unusual than finding more snapper, lionfish, or other species of shark. As far as worrying, there have been no records of White Shark attacks in the northern Gulf of Mexico since they began keeping records in 1872.
Finally, what does one do if they encounter a White Shark?
The quick answer is nothing different than with any other shark. It is true that most White Shark attacks occur at the surface but there are no records of any attacks in Florida. Burgess indicated that the Bull Shark is probably a bigger threat than the White Shark. For more information about Bull Sharks and general tips to avoid a negative shark encounter read this articlehttps://nwdistrict.ifas.ufl.edu/nat/sharktips
In a recent video, recorded near Apalachicola, a diver was on an anchor line on a decompression stop when he saw a White Shark approaching from depth. What should a diver do in this situation? Should they swim for the surface and risk decompression sickness, remain still, or return to the bottom?
The answer has a lot to do with what the shark is actually doing. Is the shark interested in the diver or acting aggressively? Burgess suggests, you assess the situation and the shark’s behavior. All options are on the table and have to be weighed against the consequences given in this scenario. As a last resort, a diver may need to make a quick but graceful exit out of the water, past the shark, and depend on their diving partners to render aid as needed. The lesson is for divers to be prepared for a variety of potential issues on every dive.
Many plants and animals have been introduced to new regions for centuries, as people have discovered new lands. These transient species are known as non-natives, and can become invasive. Invasive species occur throughout the world and may blend in, be nondescript or highly attractive; they can be plant or animal; terrestrial or aquatic; they may resemble or remind the viewer of something familiar; they may be very good at adapting to our climate and conditions which is how many invasive species get their foothold in an area. And because they have not evolved alongside our native species, when introduced to areas lacking their natural predators, they can adapt and take off.
Conditions in the SE US are ripe for many invasive contenders. Some species have been intentionally introduced and other species have been accidentally introduced. Some common invasive species include red imported fire ants, Kudzu, Privet, Chinese tallow, Japanese climbing fern, Chinaberry, and cogongrass, just to name a few on the tip of the iceberg. These species are now out-of-control, and it is unlikely they will ever be eradicated from their new home.
In 2011 alone, the Department of the Interior spent more than $100 million on invasive species prevention, early detection and rapid response, control and management, research, outreach, international cooperation and habitat restoration in the US. (USFWS) This is a drop in the bucket when you consider in FY 1999-2000, nine Florida agencies spent $90.8 million on prevention, monitoring, control, and restoration efforts. It is estimated that the annual cost of invasive plants, animals and diseases in losses to Florida’s agriculture is estimated at $179 million annually (www.defenders.org).
Much like a cancer can spread in the body, so too, when conditions are favorable can invasive species spread across the landscape. Once established in the landscape eradication is expensive; ideally early monitoring is critical to understanding its movement and dispersal, coverage, and containment. Like cancers, early detection provides better opportunity to address the situation. Within the landscape, an aggressive invasive can impact the entire ecosystem – causing a serious imbalance; followed by a cascade of impact via unforeseen collateral damage.
Take the newest aquatic threat of Lionfish. The trophic impacts of lionfish could alter the structure of native reef fish communities and potentially hamper stock rebuilding efforts of the Snapper –Grouper Complex. Additional effects of the lionfish invasion are far-reaching and could increase coral reef ecosystem stress, threaten human health, and ultimately impact the marine aquarium industry. Control strategies for lionfish are needed to mitigate impacts.
Disturbances like new roads, land clearing, and tropical weather events (hurricanes) can all provide the opportunity for invasive species to get a foothold. So, the next time you notice a plant or animal that you don’t recognize, take a picture and report it using the “I’ve Got One!” phone app or on-line to The Early Detection & Distribution Mapping System (EDDMapS.org). You can also report to the nearest Extension Agent.
March 7th: Eurasian Milfoil (Myriophyllum spicatum), Tiger Prawn (Penaeus monodon), The Cuban Tree Frog (Osteopilus septentrionalis)
Eurasian water-milfoil Myriophyllum spicatum photo by Alison Fox, University of Florida, Bugwood.org
Eurasian Water Milfoil:Eurasian water milfoil is a submerged aquatic plant that can be found in northwest Florida in lakes, rivers, and coastal marshes. Water milfoil forms a dense mat of vegetation that can block sunlight and habitat for native plants. These mats can increase water temperatures and interfere with boat traffic, fish habitat, and native aquatic plant species.
Eurasian milfoil was first documented in Florida in 1964. It was reportedly planted by aquarium plant dealers. It is still used today in the aquarium industry and obtained through suppliers and through internet sales. This plant is listed as a category II on the Florida Exotic Species Pest Plant Council List, which means it has the potential to overtake native submerged plant communities.
The spread of Eurasian milfoil can be caused by the breaking of stems and roots, which can be carried by boats, engines and trailers to other lakes and coastal marshes. To help prevent spread of Eurasian water milfoil to Florida’s waters, always clean off your boat, motor and trailer at the ramp to avoid transporting vegetative stems to other areas. In addition, never release or dispose of aquarium plants or animals into local waterways.
For more information, contact the author Chris Verlinde, Marine Science Agent 850-623-3868.
Giant Tiger Prawn Photo Credit: FWC photo by Michelle Sempsrott
Giant Tiger Prawn:This large shrimp, also known as the Asian Tiger Shrimp and the Black Tiger Shrimp, can reach lengths between 8-12 inches. It resembles are native edible penaid shrimp but differs in that it has distinct black and yellow stripes. It was brought to the U.S. from the Indo-Pacific region as an aquaculture product. There was an accidental release of 2,000 animals from a South Carolina farm in 1988. Reports of this shrimp in the wild have increased over time. They have been found in all Gulf coast states and there has been at least 1 record in each of the Florida panhandle counties. The impact of this shrimp to our area is still unknown but they have a high tolerance for salinity change and consume many types of benthic invertebrates. It is thought that they could become serious competition for our native penaid shrimp and could possible transmit diseases. If you think you have found one of these shrimp, record size location (GPS preferred) and email information to ExoticReports@MyFWC.com. To learn more about this species view the USGS factsheet.
For more information, contact the author Rick O’Connor, Sea Grant/Marine Sciences Agent 850-475-5230.
Image by Dr. Steve A Johnson 2005.
The Cuban Tree Frog:was introduced into Florida as a stowaway on vehicles and plants in the 1920’s. As of 2013, breeding populations have been recorded as far north as Georgia. Cuban Tree frogs have larger toepads and eyes than any of the native species. Being larger in size, the Cuban Tree frog out-competes other tree frogs for resources, to the point that they are predators of Florida’s tree frogs and inhibitors of native tadpoles. Juvenile Cuban Tree frogs can be distinguished from natives by their red eyes and hind legs with blue bones. Three-foot-long sections of 1.5 inch diameter PVC pipe can be placed in the landscape to monitor for tree frog species. Should Cubans be found, they should be reported and euthanized. For additional details visit: http://edis.ifas.ufl.edu/uw259.
For more information contact the author Sheila Dunning, Commercial Horticulture Agent 850-689-5850.
March 4th: Benghal Dayflower (Commelina benghalensis), Chinese Tallow (Sapium sebiferum), & Water Hyacinth (Eichhornia crassipes):
Benghal Dayflower Photo by Stanley Culpepper, University of Georgia
Benghal Dayflower (Commelina benghalensis): Also called Tropical spiderwort, is an invasive weed that creeps into nurseries, lawns, pastures and crop fields. It was first observed in the early 1990’s in Florida but can now be found throughout the panhandle and central Florida. This weed is on the Federal Noxious Weed List as well as the Florida Noxious Weed List. It has been found in California, Hawaii, Louisiana, Georgia, North Carolina, Puerto Rico as well as Florida.
This plant produces above ground and below ground flowers and
Resistant Benghal Dayflower after treatment with glyphosate. Photo by Jennifer Bearden.
can also propagate via cut stems. Thus light cultivation and mowing will cause this aggressive weed to spread. Benghal Dayflower is extremely tolerant of glyphosate.
Benghal Dayflower can be distinguished from other dayflowers in Florida by:
Violet rather than blue flowers,
Broader rather than longer leaves (Length to width ratio is less than 3:1),
Presence of hairs on tops and edges of leaves,
Presence of white, subterranean stems and flowers.
Physical methods sometimes cause infestations to spread rather than controlling them. There are no know biological control methods, although maintain weed-free ground cover helps out compete the dayflower. Chemical control methods are dictated by the location of the weed. If it is in a lawn or pasture, 2,4-D can be used.
For more information contact the author Jennifer Bearden, Agriculture Extension Agent, 850-689-5850.
Chinese Tallow Photo Credit Cheryl McCormick, UF, www.bugwood.org
Chinese Tallow (Sapium sebiferum): Chinese Tallow a.k.a. Popcorn Tree: Benjamin Franklin has been blamed for introducing the invasive exotic Chinese Tallow tree to the Southeast when he mailed seeds to a planter after one of his trips to London in the late 1700’s. However, recent DNA work has traced the invasive strain to federal scientists’ importations in 1905. No matter. The “Popcorn Tree,” as it’s also called because of its white seeds, has invaded the Gulf of Mexico coast from Texas to Florida, especially the wetlands and bottomland forests. A mature tree may produce as many as 100,000 seeds annually. These seeds can be spread by birds or moving water and expedite the trees’ takeover of habitat.
The sap and berries are toxic to humans and livestock. It has been planted for its red fall color, but it crowds out native wetland species such as black gum and red maple, both noted for their red fall leaves. Its tolerance to flooding and saltwater can also make it a threat to bald cypress.
Recently research by scientists of the US Forest Service and others has shown that dissolved oxygen and pH levels in the leaf litter of the tallow tree are fatal to the early stage eggs of the leopard frog. While tallow trees provide a nectar source for bees and have been investigated as a biofuel source, the damage to wetlands caused by these invaders more than offsets the positive aspects of the plant.
To control this species, small seedlings may be hand pulled, especially in wet areas, but care should be taken to leave no root pieces to resprout. Herbicides including triclopyr can control Chinese Tallow. Larger trees can be controlled by “Hack and Squirt” or “Cut stump” applications and smaller sprouts can be controlled by a basal bark application. These methods of control are described at http://edis.ifas.ufl.edu/ag245 and can be used on other woody pests such as chinaberry or coral ardisia. More information is available at http://edis.ifas.ufl.edu/ag148 and http://plants.ifas.ufl.edu/node/676. For local assistance, contact your county UF IFAS Extension office.
For more information contact Jed Dillard, Livestock & Forages Extension Agent by phone at 850-342-0187.
Water Hyacinth Photo Credit: Vic Ramey, UF/IFAS
Water Hyacinth (Eichhornia crassipes):The water hyacinth is a floating non-native plant, which if left unchecked and allowed to grow to its maximum potential, can weigh up to 200 tons per acre of water. Once it gets into rivers, it can choke out other vegetation and make navigation difficult if not impossible, because the plants will grow intertwined and form huge floating mats that can root on muddy surfaces. Water hyacinth is a wolf in sheep’s clothing—it is a highly ornamental plant. The plant will be several inches tall with showy lavender flowers and rounded, shiny, smooth leaves. These leaves are attached to spongy stalks that help keep the plants afloat. The prolific roots are dark and feathery. Although here in northwest Florida most of it dies back in the winter, it is able to regrow when the weather and water warm up. This weed can be controlled by physical removal, through biological control options—water hyacinth weevils will be useful in keeping the plant populations down—and by chemical means. For more information on hyacinth and other weed control in Florida ponds, please see the UF IFAS publication Weed Control in Florida Ponds. If you have any questions about identifying a pond weed, contact your friendly local county Extension agent.
For more information contact the author Libbie Johnson Agriculture Extension Agent, 850-475-5230.
March 3rd: Wild Hogs (Sus scrofa) & Lionfish (Pterois volitans):
The impact of wild hogs on the environment is soil erosion, decreased water quality, spread of other invasive plants, damage to agricultural crops, and damage to native plants and animals. Photo by Jennifer Bearden
Wild Hogs: Wild Hogs, also called Feral Hogs, are not native to the U.S. Domesticated pigs were introduced by early settlers because they could adapt to a wide variety of habitats. These pigs were kept on open ranges and used as a food source for settlers and Native Americans. In the early 1900’s, true Eurasian wild boars were introduced for hunting purposes. The population of wild hogs today are hybrids of Eurasian and domestic pigs.
Wild hogs are highly adaptable and can find suitable habitat easily. Wild hogs can be all shapes, sizes and colors since they are hybrids of many different breeds. Wild hogs sometimes resemble their domestic relatives but sometimes resemble their Eurasian backgrounds.
Wild hogs are probably the most prolific large mammals in the world. They reach sexual maturity at a young age. Females have multiple litters of 3-8 piglets per year. Natural mortality rates are low. Wild hog females and young live and travel in groups called sounders. Sounders typically have 1 to 3 adults and several young. When females reach maturity, they either stay with the sounder or they go out and form a new sounder with other young females. Young males leave the sounder alone at about 16 months.
Wild hogs are opportunistic omnivores that feed by rooting and grazing. This rooting behavior is why we consider them to be a pest. The impact of wild hogs on the environment is soil erosion, decreased water quality, spread of other invasive plants, damage to agricultural crops, and damage to native plants and animals. They have been documented as threats to threatened and endangered species. They can significantly impact populations of reptiles, amphibians, small mammals, ground nesting birds and even deer.
Wild hogs pose a health risk to humans because they can carry numerous diseases and parasites. Care should be taken when handling wild hogs. Wear gloves, cover any open wounds, and wear clothing that can be cleaned thoroughly. Human hunting is the most significant cause of mortality in wild hogs, although hunting alone will not control hog populations in a good habitat. The most effective way to remove wild hogs from a location is a combination of trapping and shooting.
In Florida, wild hogs may be hunted year round on private land (with permission of the landowner) and at night with no permit required. Hogs may be trapped year round. Wild hogs cannot be trapped and released onto public land. Trapped wild hogs can only be transported with a permit from FDACS) to slaughter or to an approved Feral Swine Holding Facility. For more information on Wild Hogs, go to: http://edis.ifas.ufl.edu/uw322 and http://www.myfwc.com/hunting/by-species/wild-hog/. For more information on Wild Hogs, go to: http://edis.ifas.ufl.edu/uw322
For more information contact the author Jennifer Bearden, Agriculture Extension Agent, 850-689-5850.
Photo courtesy of Florida Sea Grant
Lionfish:The Red Lionfish are a predatory reef fish that are non-native invasive species and have spread throughout Florida Waters. They are members of the family Scorpaenidae, all members are venomous and the lionfish is no exception. This fish is relatively small typically ranging from 12-15 inches in length and have a zebra-like appearance with long, showy pectoral fins. They have a row of long, dorsal spines that contain venom glands. Their native range is the South Pacific and Indian Oceans and preferred habitat is on offshore reef structures. These fish are considered to be voracious eaters feeding on native fish, reducing vital native populations, and competing for food with native fish such as grouper and snapper.
With few predators, these fish are thriving in Florida waters, even in the northern Gulf of Mexico. They reproduce often, sometimes all year, with their eggs hatching after about two days. They also consume a variety of local species, causing 80% decline in reef fish recruitment and loss of some economically important species. These fish are able to expand their stomachs for large meals and can survive starvation for over 12 weeks. These fish are an invasive species in our local waters and removal is encouraged. The most effective control of this species is removal by human. These fish are cryptic and nocturnal so locating them can be tricky. Spearfishing is the method of choice, since lionfish rarely bite a hook and line. Florida Fish and Wildlife Commission (FWC) changed regulations to increase harvesting opportunities. Such changes include no requirement for a recreational fishing license when using spearing devices (pole spear, a Hawaiian Sling, handheld net, or spearing devices marked for use on lionfish), and no recreational or commercial bag limit, though recreational fishing license is required for other fishing methods. Check the FWC regulations before fishing or diving for these species.
Lionfish are venomous, must be handled carefully, venom glands occur on the dorsal, pelvic and anal spines. Lionfish sightings should be reported at 877.786.7267, if stung seek medical attention as soon as possible. Rarely are stings fatal unless the person has an allergy to the venom. The Poison Help Hotline can be reached at 800.222.1222. Sighting information is being collected to track the movement of these species. Fill out the online report on the USGS website or the REEF website. Stay up to date on research as it pertains to this species at www.flseagrant.org. For locals you can report sighting also at www.lionfishmap.org.
For more information contact the author Brooke Saari, Sea Grant Marine Science Extension Agent, 850-689-5850.
