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Gardiner J.M.,University of South Florida | Gardiner J.M.,Center for Shark Research | Atema J.,Boston University | Atema J.,National Oceanic and Atmospheric Administration | Atema J.,Woods Hole Oceanographic Institution
Current Biology | Year: 2010

The direction of an odor signal source can be estimated from bilateral differences in signal intensity and/or arrival time. The best-known examples of the use of arrival time differences are in acoustic orientation [1]. For chemoreception, animals are believed to orient by comparing bilateral odor concentration differences, turning toward higher concentrations [2-4]. However, time differences should not be ignored, because odor plumes show chaotic intermittency, with the concentration variance several orders of magnitude greater than the concentration mean (e.g., [5]). We presented a small shark species, Mustelus canis, with carefully timed and measured odor pulses directly into their nares. They turned toward the side stimulated first, even with delayed pulses of higher concentration. This is the first conclusive evidence that under seminatural conditions and without training, bilateral time differences trump odor concentration differences. This response would steer the shark into an odor patch each time and thereby enhance its contact with the plume, i.e., a stream of patches. Animals with more widely spaced nares would be able to resolve smaller angles of attack at higher swimming speeds, a feature that may have contributed to the evolution of hammerhead sharks. This constitutes a novel steering algorithm for tracking odor plumes. © 2010 Elsevier Ltd.


News Article | November 2, 2016
Site: www.marketwired.com

The organization and its collaborating scientists satellite-tagged six great white sharks, including the first male NANTUCKET, MA--(Marketwired - November 02, 2016) - OCEARCH, a globally recognized nonprofit dedicated to the study and tracking of keystone marine species such as great white sharks, just concluded its 27th research expedition in Nantucket, MA. During the expedition the organization and its collaborating scientists successfully tagged, and sampled six great white sharks. The data collected will help researchers understand the entire North Atlantic white shark population. "More movement data remains the key to a comprehensive understanding of why so many white sharks are there," said Dr. Simon Thorrold, Senior Scientist and Director of the Ocean Life Institute at Woods Hole Oceanographic Institution in Massachusetts. "Understanding where, when, and how the sharks use this area can help us better predict how human activities might be impacting them." After tagging three great white sharks -- Grey Lady, Miss Costa, and Madaket Millie -- within three days of expedition, OCEARCH was on hold for several days due to intense weather conditions. After its weather hold, OCEARCH tagged three more sharks, including two males -- the first ever satellite-tagged in the region. "It's especially exciting that we sampled and tagged our first large males, one of which was sexually mature," said lead scientist Dr. Robert Hueter, Director of the Center for Shark Research at Mote Marine Laboratory. "Once a male shark has been satellite tagged, you can overlap his tracks with the female tracks and begin to understand where they meet, eventually locating the breeding areas." In 2012 and 2013, OCEARCH tagged five mature, female great white sharks in the North Atlantic. Sharks like Lydia and Katharine have connected millions of people to their real-time migratory tracks. Lydia, a mature female, was the first satellite-tagged white shark documented crossing the mid-Atlantic Ridge; and Katharine, an immature female, was also the first great white shark documented entering the Gulf of Mexico. The data gathered from the six newly tagged great white sharks will build on these previous findings. "The six large white sharks sampled and tagged during Expedition Nantucket provide a major leap forward in science in the Northwest Atlantic," Dr. Hueter added. "We more than doubled the sample size of large sharks sampled for the institutions taking part in OCEARCH-supported studies." OCEARCH's mission is to enable data collection by providing collaborating researchers and institutions unprecedented access to mature marine animals. During the Nantucket Expedition, OCEARCH collaborated with scientists from the Center for Shark Research at Mote Marine Laboratory, Woods Hole Oceanographic Institution, University of Massachusetts, Wildlife Conservation Society' New York Aquarium, Adventure Aquarium, University of North Florida, University of South Carolina, Auburn University, College of Charleston, Cape Canaveral Scientific, Georgia Aquarium, and Cape Eleuthera Institute. "Up to 15 different researchers from 12 institutions received biological samples from each animal and are now analyzing results from the blood, mucus, muscle, parasite, genetic, and other samples collected," said Alisa Newton, Head of Aquatic Health at the Wildlife Conservation Society' New York Aquarium. "They will use the results to better define the normal physiology, biology and health of the Atlantic white shark population and, through that, the health of the environment that we share." All sharks were fitted with a satellite transmitter tag, PSAT tag, and an acoustic tag. In combination with the satellite tags, the PSAT tags will allow researchers to reconstruct three-dimensional movements of the white sharks up to six months after deployment. The resulting data will shed light on the interactions between white shark behavior and their physical environment. "Identifying habitat preferences will be an important component of comprehensive conservation strategy for white sharks in the North Atlantic," said Dr. Thorrold. "The fact that the first two male sharks to be satellite-tagged in the Atlantic also got PSAT tags was a real bonus for the expedition, and we are waiting eagerly to see how these tracks differ (or not) from the females tagged in this and previous expeditions." As the sharks' fins break the surface, the satellite tag will transmit their locations. "It's amazing to see that three of the sharks, Madaket Millie, YETI, and Grey Lady, are still in the area while Miss Costa is off the coast of South Carolina, George is off the coast of Virginia, and Cisco is off the coast of Delaware," said Chris Fischer, OCEARCH Founding Chairman and Expedition Leader. "We are learning so much already." Combined with the nine juvenile white sharks OCEARCH tagged during Expedition Montauk, there are now a total of 20 satellite-tagged white sharks of various life stages swimming around the North Atlantic. "The open access satellite data reporting in from these sharks will bring the previously blurry picture of white shark movement patterns into focus in the Atlantic, showing us the areas that are critical for white shark survival," Dr. Hueter said. Anyone and everyone can follow the sharks' movements by accessing the near-real time, free online Global Shark Tracker or by downloading the Global Shark Tracker App available for Apple and Android platforms. About OCEARCH OCEARCH is a recognized world leader in generating critical scientific data related to tracking (telemetry) and biological studies of keystone marine species such as great white and tiger sharks, in conjunction with conservation outreach and education at a measurable global scale. OCEARCH shares real-time migration data through OCEARCH's Global Shark Tracker -- In 2015, OCEARCH open-sourced the data on the Global Shark Tracker to 2.3 million users. OCEARCH also inspires current and future generations of explorers, scientists, and stewards of the ocean through its STEM Learning Program. The free STEM Curriculum, available for grades K-8 and created in partnership with Landry's, Inc. enables students to learn STEM skills while following the real-time data on the movements of their favorite sharks. The researchers OCEARCH supports work aboard the M/V OCEARCH, a 126' Cat-powered vessel equipped with a 75,000 lb. hydraulic research platform, where the ship serves as both mothership and at-sea laboratory. Scientists have approximately 15 minutes of access to live, mature sharks to conduct up to 12 studies. The sharks are measured, tissue and blood samples are collected, and satellite and acoustic transmitters are attached. Over 131 researchers from 69 regional and international institutions have partnered with OCEARCH. About Costa As the leading manufacturer of the world's clearest polarized performance sunglasses, Costa offers superior lens technology and unparalleled fit and durability. Still handcrafted today in Florida, Costa has created the highest quality, best performing sunglasses for outdoor enthusiasts since 1983. For Costa, conservation is all about sustainable fishing. Many fisheries that should be vibrant and healthy are all but devoid of native fish because they have fallen victim to poor fishing practices, unregulated development, lack of watershed protection or all of the above. Costa works with partners around the world to help increase awareness and influence policy so that both the fish and fishermen of tomorrow will have healthy waters to enjoy. Costa encourages others to help in any way they can. About Aurora Flight Sciences Aurora Flight Sciences is a leader in the development and manufacturing of advanced unmanned systems and aerospace vehicles. At the core of the company's DNA is a commitment to the science of autonomous flight; whether that means a fully autonomous drone, or a program that is breaking new ground in the interface between man and machine as relates to flight. Since its founding in 1989, Aurora's unmanned aircraft have supported a number of environmental and educational missions across the globe. From the North Slope in Alaska, to the wilderness in South Africa, Aurora has conducted dozens of successful scientific and philanthropic operations, proving the countless abilities and benefits of unmanned flight. For more information, visit www.aurora.aero.


Chapman D.D.,Marine Conservation Institute | Feldheim K.A.,Pritzker Laboratory for Molecular Systematics and Evolution | Papastamatiou Y.P.,University of St. Andrews | Hueter R.E.,Center for Shark Research
Annual Review of Marine Science | Year: 2015

The overexploitation of sharks has become a global environmental issue in need of a comprehensive and multifaceted management response. Tracking studies are beginning to elucidate how shark movements shape the internal dynamics and structure of populations, which determine the most appropriate scale of these management efforts. Tracked sharks frequently either remain in a restricted geographic area for an extended period of time (residency) or return to a previously resided-in area after making long-distance movements (site fidelity). Genetic studies have shown that some individuals of certain species preferentially return to their exact birthplaces (natal philopatry) or birth regions (regional philopatry) for either parturition or mating, even though they make long-distance movements that would allow them to breed elsewhere. More than 80 peer-reviewed articles, constituting the majority of published shark tracking and population genetic studies, provide evidence of at least one of these behaviors in a combined 31 shark species from six of the eight extant orders. Residency, site fidelity, and philopatry can alone or in combination structure many coastal shark populations on finer geographic scales than expected based on their potential for dispersal. This information should therefore be used to scale and inform assessment, management, and conservation activities intended to restore depleted shark populations. Copyright © 2015 by Annual Reviews. All rights reserved.


Gelsleichter J.,Center for Shark Research | Szabo N.J.,University of Florida
Science of the Total Environment | Year: 2013

The presence of human pharmaceuticals in sewage-impacted ecosystems is a growing concern that poses health risks to aquatic wildlife. Despite this, few studies have investigated the uptake of active pharmaceutical ingredients (APIs) in aquatic organisms. In this study, the uptake of 9 APIs from human drugs was examined and compared in neonate bull sharks (Carcharhinus leucas) residing in pristine (Myakka River) and wastewater-impacted (Caloosahatchee River) tributaries of Florida's Charlotte Harbor estuary. The synthetic estrogen used in human contraceptives (17α-ethynylestradiol) and 6 of the selective serotonin/norepinephrine reuptake inhibitors (citalopram, fluoxetine, fluvoxamine, paroxetine, sertraline, venlafaxine) used in human antidepressants were observed at detectable and, in some cases, quantifiable levels in plasma of Caloosahatchee River sharks. Comparatively, only venlafaxine was detected in the plasma of a single Myakka River shark at a level below the limit of quantitation. These results suggest that sharks residing in wastewater-impacted habitats accumulate APIs, a factor that may pose special risks to C. leucas since it is one of few shark species to regularly occupy freshwater systems. Further research is needed to determine if the low levels of API uptake observed in Caloosahatchee River bull sharks pose health risks to these animals. © 2013 Elsevier B.V.


News Article | October 23, 2015
Site: www.nature.com

Cuba is surrounded by sharks. Fishermen catch them, residents eat them and, increasingly, tourists are coming to see them. Now the island nation is gearing up to manage them, and its efforts are bolstering a nascent environmental partnership with the United States. “It’s a big step forward for Cuba and the region,” says Jorge Angulo-Valdés, head of the Marine Conservation Group at the University of Havana’s Center for Marine Research and a visiting professor at the University of Florida in Gainesville. “It’s time for us to get together, identify common goals in resource management and make them work.” On 21 October, Cuba plans to release a management plan that will lay the groundwork for research and, eventually, regulations to protect extensive but largely undocumented shark and ray populations. Roughly half of the 100 species of shark resident in the Caribbean Sea and Gulf of Mexico have been seen in Cuban waters, including some — such as the whitetip (Carcharhinus longimanus) and longfin mako (Isurus paucus) — that have experienced sharp declines elsewhere. The Cuban government has consulted with environmentalists and academics from the United States and other countries in developing the plan. “Cuba is a kind of biodiversity epicentre for sharks,” says Robert Hueter, director of the Center for Shark Research at the Mote Marine Laboratory and Aquarium in Sarasota, Florida, who is one of those working with the Cuban scientists. “The science is not at a level yet to do rigorous stock estimates, but we are moving in that direction with this plan.” Most of what is known about Cuba’s shark populations has come from the fishing industry, which often captures sharks as by-products of its regular operations. The Cuban government has already established marine protected areas along 20% of its coastline and is planning to expand that network within the 70,000 square kilometres of its coastal fishery. It has also begun to regulate the equipment used in fishing, and is looking to establish catch limits for various fish species, including sharks. Both US and Cuban scientists say that the collaboration is helping to pave the way for more formal cooperation now that the two cold-war foes have re-established political relations. In April, the US National Oceanic and Atmospheric Administration (NOAA) sent a research vessel on a cruise around the island with Cuban scientists. And on 5 October, US secretary of state John Kerry and Cuban officials announced at an oceans conference in Chile that the two nations were finalizing plans to cooperate on research, education and management in marine protected areas. The agreement could be finalized as early as next month, says Billy Causey, regional director for NOAA’s Office of National Marine Sanctuaries in Key West, Florida. US environmentalists began pushing the idea of cooperation with Cuba on marine conservation after the 2008 election of President Barack Obama, who pledged during the campaign to engage with Cuba. The first signs of real progress came in September 2009, says Daniel Whittle, who heads the Cuba programme for the Environmental Defense Fund (EDF), an environmental group based in New York City. Then, the United States allowed four Cuban scientists, three of whom were marine and coastal researchers, to attend a series of meetings in the country. And in November last year, Angulo-Valdés was part of a cadre of Cuban scientists that visited the state department and several members of Congress. A month later, Obama ordered the restoration of diplomatic ties with Cuba. “It’s slowly beginning to change,” says Whittle, referring to links between the nations. “That’s why the announcement in Chile was so significant: finally the two governments publicly acknowledged that they are in fact working directly together on environmental issues.” The EDF and other conservation groups have been trying to build cooperation between Cuba, Mexico and the United States within the Gulf of Mexico. NOAA’s April cruise, which focused on tallying the larvae of bluefin tuna (Thunnus thynnus) in Cuban and Mexican waters, marked the first formal government engagement on that front since Obama’s December announcement, Causey says. The main question facing the shark-management plan is whether the Cuban government will be able to mobilize enough money to implement it. The EDF and other groups have been raising funds to pay for some of the initial work on the plan, including training fishing crews to identify and report the sharks that they catch. But scientists need to conduct population surveys that are independent of those done by commercial fisheries, and Cuban research institutions are already stretched thin. The country has only two operational research vessels, and scarce resources to equip and operate them. The kind of tags needed to track shark movements through satellites can cost US$2,500 each. So far, Cuba has tagged just four sharks with such devices. “We have to see how the government implements the plan, and how they get around the funding problem,” Angulo-Valdés says. “It’s going to be a challenge.”


Hueter R.E.,Center for Shark Research | Tyminski J.P.,Center for Shark Research | de la Parra R.,Proyecto Domino Chooj Ajauil Asociacion Civil
PLoS ONE | Year: 2013

Whale sharks, Rhincodon typus, aggregate by the hundreds in a summer feeding area off the northeastern Yucatan Peninsula, Mexico, where the Gulf of Mexico meets the Caribbean Sea. The aggregation remains in the nutrient-rich waters off Isla Holbox, Isla Contoy and Isla Mujeres, Quintana Roo for several months in the summer and then dissipates between August and October. Little has been known about where these sharks come from or migrate to after they disperse. From 2003-2012, we used conventional visual tags, photo-identification, and satellite tags to characterize the basic population structure and large-scale horizontal movements of whale sharks that come to this feeding area off Mexico. The aggregation comprised sharks ranging 2.5-10.0 m in total length and included juveniles, subadults, and adults of both sexes, with a male-biased sex ratio (72%). Individual sharks remained in the area for an estimated mean duration of 24-33 days with maximum residency up to about 6 months as determined by photo-identification. After leaving the feeding area the sharks showed horizontal movements in multiple directions throughout the Gulf of Mexico basin, the northwestern Caribbean Sea, and the Straits of Florida. Returns of individual sharks to the Quintana Roo feeding area in subsequent years were common, with some animals returning for six consecutive years. One female shark with an estimated total length of 7.5 m moved at least 7,213 km in 150 days, traveling through the northern Caribbean Sea and across the equator to the South Atlantic Ocean where her satellite tag popped up near the Mid-Atlantic Ridge. We hypothesize this journey to the open waters of the Mid-Atlantic was for reproductive purposes but alternative explanations are considered. The broad movements of whale sharks across multiple political boundaries corroborates genetics data supporting gene flow between geographically distinct areas and underscores the need for management and conservation strategies for this species on a global scale. © 2013 Hueter et al.


Heupel M.R.,Center for Shark Research | Heupel M.R.,Australian Institute of Marine Science | Simpfendorfer C.A.,Center for Shark Research | Simpfendorfer C.A.,James Cook University
Marine Ecology Progress Series | Year: 2011

Defining the role and impact of mortality within aquatic populations is often difficult. As a result, we still lack a clear understanding of the level of mortality in natural populations and the role habitat may play in survival. We used long-term acoustic monitoring of neonate bull sharks Carcharhinus leucas in a south Florida estuary to determine mortality rates within this population. Estimates of natural, fishing and total mortality varied among the years examined, but not significantly, suggesting similar survival among years with the majority of individuals (77%) surviving beyond 18 mo. Compared with other juvenile sharks, mortality rates of C. leucas were low. The results indicate that the use of mesohaline estuarine habitats by C. leucas may provide benefits that are not present in more marine habitats where their counterparts reside. Use of estuarine regions may be a successful ecological strategy for improving survival because of reduced predation and competition. © 2011 Inter-Research.


Whitney N.M.,Center for Shark Research | Pratt Jr. H.L.,Center for Shark Research | Pratt T.C.,Center for Shark Research | Carrier J.C.,Albion College
Endangered Species Research | Year: 2010

Little is known about the reproductive strategies and mating behaviour of most sharks. Understanding mating behaviour is important as it can determine reproductive success and possibly rates of multiple paternity and fecundity. Additionally, some sharks appear to have specific habitat requirements for mating activities. We tested the utility of a 3-dimensional acceleration logger to identify mating events in free-living nurse sharks Ginglymostoma cirratum in an area where behaviours can be observed directly, thus allowing corroboration of acceleration data. Loggers were attached to 4 adult females and were recovered after recording periods of 23.2 to 99.8 h (mean ± SD = 50.0 ± 35.1 h). We used acceleration data to classify several behaviours, including swimming, resting, resting in a surge zone, and mating, with examples of each behaviour confirmed via direct observation. Twenty-six mating events were inferred from acceleration data, ranging from 21 s to 20.1 min in duration (median = 2.22 min), with no events taking place during the nighttime hours between 23:00 and 07:00 h. Four events lasted longer than 9 min and took place during periods when loggerequipped sharks were not acoustically detected within the shallow study site. The similarity in mating behaviours between this and some other species raises the possibility that accelerometry could be used to quantify mating in a variety of shark species. This is the first study to classify mating and other behaviours in free-living sharks from acceleration data. © Inter-Research 2010.


Simpfendorfer C.A.,Center for Shark Research | Wiley T.R.,Center for Shark Research | Wiley T.R.,Texas Parks and Wildlife Department | Yeiser B.G.,Center for Shark Research
Biological Conservation | Year: 2010

Understanding the movement and habitat use patterns of threatened species is essential to effective conservation planning. Modern tracking techniques such as active tracking and passive acoustic monitoring can be useful tools in elucidating this information for aquatic species. To aid in the development of conservation strategies for juvenile critically endangered smalltooth sawfish (Pristis pectinata) their fine scale movements and habitat use in southwest Florida were studied using a combination of these techniques. Between 2002 and 2006 a total of 12 individuals were actively tracked for periods of up to 24. h to provide detailed habitat use and movement parameters (distance moved, speed, and linearity). Smaller individuals (<100. cm stretched total length (STL)) had the smallest home ranges, low linearity of movement and had a preference for very shallow mud banks. Juveniles >100. cm STL demonstrated larger home ranges, preference for shallow mud or and sand banks, and remained close to mangrove shorelines. Tide was found to be the main factor influencing movement on short time scales. Sawfish <150. cm STL spend the majority of their time in water <50. cm, while larger juveniles spend most of their time in water 50-100. cm deep. From 2003 to 2007 a total of 22 individuals were fitted with acoustic tags for long-term monitoring. Juveniles >130. cm had high levels of site fidelity for specific nursery areas for periods up to almost 3. months, but the smaller juveniles had relatively short site fidelity to specific locations. The use of a combination of tracking and monitoring techniques provided an expanded range of information by generating both short and long term data on habitat use. The data demonstrated that the conservation of shallow mud and sand banks, and mangrove shorelines will benefit the recovery of these endangered elasmobranchs. © 2010 Elsevier Ltd.


Gardiner J.M.,University of South Florida | Gardiner J.M.,Center for Shark Research | Atema J.,Boston University | Hueter R.E.,Center for Shark Research | Motta P.J.,University of South Florida
PLoS ONE | Year: 2014

The underwater sensory world and the sensory systems of aquatic animals have become better understood in recent decades, but typically have been studied one sense at a time. A comprehensive analysis of multisensory interactions during complex behavioral tasks has remained a subject of discussion without experimental evidence. We set out to generate a general model of multisensory information extraction by aquatic animals. For our model we chose to analyze the hierarchical, integrative, and sometimes alternate use of various sensory systems during the feeding sequence in three species of sharks that differ in sensory anatomy and behavioral ecology. By blocking senses in different combinations, we show that when some of their normal sensory cues were unavailable, sharks were often still capable of successfully detecting, tracking and capturing prey by switching to alternate sensory modalities. While there were significant species differences, odor was generally the first signal detected, leading to upstream swimming and wake tracking. Closer to the prey, as more sensory cues became available, the preferred sensory modalities varied among species, with vision, hydrodynamic imaging, electroreception, and touch being important for orienting to, striking at, and capturing the prey. Experimental deprivation of senses showed how sharks exploit the many signals that comprise their sensory world, each sense coming into play as they provide more accurate information during the behavioral sequence of hunting. The results may be applicable to aquatic hunting in general and, with appropriate modification, to other types of animal behavior. © 2014 Gardiner et al.

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