Tag Archive | "rosenstiel school of marine and atmospheric science"

Scientists Use Ultrasound to Study Shark Reproduction

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Scientists Use Ultrasound to Study Shark Reproduction


Special to UM News

A female tiger shark at Tiger Beach, Bahamas. Photo by Neil Hammerschlag.

A female tiger shark at Tiger Beach, Bahamas. Photo by Neil Hammerschlag.

MIAMI, Fla. (March 2, 2016) — Researchers from the University of Miami’s Rosenstiel School of Marine and Atmospheric Science and the University of New England have used the same ultrasound imaging technology used by medical professionals on pregnant women to study the reproductive biology of female tiger sharks. Their study offers marine biologists a new technique to investigate the reproductive organs and determine the presence of embryos in sharks without having to sacrifice the animal first, which was commonly done in the past.

In the study, published in the latest edition of the Journal of Aquatic Biology, researchers performed in-water ultrasounds on live tiger sharks (Galeocerdo cuvier) and took blood samples for hormone analysis to determine the reproductive status of females at Tiger Beach in the Bahamas, a site known for its year-round abundance of tiger sharks. The new method allows researchers to determine if the female sharks at Tiger Beach were mature and pregnant.

“Using the same ultrasound imaging technology used on pregnant women, we discovered Tiger Beach was important for females of different life stages, and that a high proportion of tiger sharks were pregnant during winter months,” said James Sulikowski, a professor in the University of New England’s Department of Marine Science.

“Our data suggests that Tiger Beach may function as a refuge habitat for females to reach maturity as well as a gestation ground where pregnant females benefit from calm, warm waters year round that help incubate the developing embryos and speed up gestation,” said study co-author Neil Hammerschlag, research assistant professor at the Rosenstiel School and Abess Center for Ecosystem Science and Policy.

Populations of many migratory marine predators such as sharks are experiencing large declines across the globe and fishing aggregations of pregnant females can significantly impact the health of local and regional populations. Tiger Beach is located within the Bahamas Exclusive Economic Zone, where shark fishing has been prohibited since 2011. The relatively high abundance of tiger sharks in the Bahamas compared to the rest of the Caribbean where populations are much lower could be attributed in part to the protection of mature and gravid females in the Bahamas shark sanctuary.

“It is crucial for marine biologists to understand their behaviors to provide information for resource managers to effectively protect and manage them,” said Hammerschlag

 

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Shark Hotspots and Commercial Fishing Overlap

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Shark Hotspots and Commercial Fishing Overlap


Researchers who tracked movements of sharks and longline fishing vessels in North Atlantic found significant overlap driving shark declines.

Mako SharkMIAMI, Fla. (January 25, 2016)—A new study from an international team of scientists found commercial fishing vessels target shark hotspots, areas where sharks tend to congregate, in the North Atlantic. The researchers suggest that sharks are at risk of being overfished in these oceanic hotspots.

Neil Hammerschlag, research assistant professor at the University of Miami’s Rosenstiel School of Marine and Atmospheric Science and Abess Center for Ecosystem Science and Policy, was part of the scientific team that published its findings in the January 25 issue of the journal Proceedings of the National Academy of Sciences. The authors report in the study that catch quotas for sharks by commercial fishers might be necessary to protect oceanic sharks.

“Our research clearly demonstrates the importance of satellite tagging data for conservation,” said Hammerschlag, director of the UM Shark Research and Conservation Program who conducted the satellite tagging and tracking of several shark species in the northwestern Atlantic for the study. “The findings both identify the problem as well as provide a path for protecting oceanic sharks.”

During a four-year period from 2005 to 2009, the researchers tracked more than 100 sharks equipped with satellite tags from six different species in the North Atlantic while concurrently tracking 186 Spanish and Portuguese GPS-equipped longline fishing vessels. They found that the fishing vessels and sharks occurred in ocean fronts characterized by warm water temperature and high productivity, including the Gulf Stream and the North Atlantic Current/Labrador Current Convergence Zone near Newfoundland.

“Many studies have tracked sharks, and many studies have tracked fishing vessels, but fine-scale tracking of sharks and fishing vessels together is lacking, even though this should better inform how shark fisheries should be regulated,” said David Sims of the Marine Biological Association, and the senior author of the study.

According to the researchers, about 80 percent of the range for two of the most heavily fished species tracked—the blue and mako sharks—overlapped with the fishing vessels’ range, with some individual sharks remaining near longlines for over 60 percent of the time they were tracked. Blue sharks were estimated to be vulnerable to potential capture 20 days per month, while the mako sharks’ potential risk was 12 days per month.

“Although we suspected overlap might be high, we had no idea it would be this high. Space-use overlap on this scale potentially increases shark susceptibility to fishing exploitation, which has unknown consequences for populations,” said Nuno Queiroz of the University of Porto, Portugal, the lead author of the study.

Tens of millions of ocean-dwelling sharks are caught by commercial fishing operations each year. The researchers suggest that a lack of data on where sharks are likely to encounter fishing vessels has hampered current shark conservation efforts.

The researchers propose that because current hotspots of shark activity are at particularly high risk of overfishing, the introduction of conservation measures, such as catch quotas or size limits, will be necessary to protect oceanic sharks that are commercially important to fleets worldwide at the present time.

In addition to Queiroz and Hammerschlag, co-authors of the study, titled “Ocean-wide tracking of pelagic sharks reveals extent of overlap with longline fishing hotspots,” include Nicolas E. Humphries, Gonzalo Mucientes, Fernando P. Lima, Kylie L. Scales, Peter I. Miller, Lara L. Sousa, Rui Seabra, and David W. Sims. Instituations contributing to the research were the Marine Biological Association of the United Kingdom, Universidade da Porto in Portugal, National Oceanography Centre Southampton, University of Southampton, Fundación CETMAR, University of Miami, Plymouth Marine Laboratory, University of California Santa Cruz, National Oceanic and Atmospheric Administration, and Faculdade de Ciências da Universidade do Porto.

Hammerschlag’s work was supported by the Disney Worldwide Conservation Fund, Batchelor Foundation, and West Coast Inland Navigation District in Florida. The research study was part of the European Tracking of Predators in the Atlantic (EUTOPIA) initiative.

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Gulf Ocean Current Linked to Red Tide

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Gulf Ocean Current Linked to Red Tide


RedTide

Florida red tides) occur often on the West Florida Shelf. Photo by P. Schmidt, Charlotte Sun

MIAMI, Fla. (January 22, 2016) – A new study found that a major ocean current in the Gulf of Mexico plays an important role in sustaining Florida red tide blooms. The Rosenstiel School of Marine and Atmospheric Science research team suggest that the position of the Loop Current can serve as an indicator of whether the algal bloom will be sustained, and provide warning of possible hazardous red tide conditions in coastal areas.

Florida red tide is a harmful algal bloom produced by the dinoflagellate Karenia brevis that causes respiratory impairment in humans and marine life, and is responsible for shellfish poisoning.

The researchers collected data of Karenia brevis concentrations, river outflows, wind conditions, and sea surface heights to study the physical conditions during periods of large Karenia brevis blooms and periods of no bloom. This research looked at the continuation of a bloom and not the formation of a red tide bloom.

They found that when the Loop Current is in a northern position, it allow a bloom to continue when other conditions were favorable, but when in a southern position a bloom could not be sustained. The Loop Current, which enters the Gulf of Mexico through the Yucatan Straits, is one of the most important features in the Gulf ocean circulation system.

“Knowing the approximate position of the Loop Current can be an indicator if a bloom will be sustained, and provide a warning for possible hazardous conditions,” said UM Rosenstiel School Ph.D. student Grace Maze, lead author of the study.

The study, titled “Historical Analysis of Environmental Conditions During Florida Red Tide” was published in the Dec. 2015 issue of the journal Harmful Algae. The study’s authors include: Maria J Olascoaga and Larry Brand of the UM Rosenstiel School.

The Oceans and Human Health Center at the University of Miami Rosenstiel School supported the project through a National Science Foundation grant and Gulf of Mexico Research Initiative funds provided by the Consortium provided for Advanced Research on Transport of Hydrocarbon in the Environment (CARTHE).

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Hurricane Hero Bryan Norcross Shares His Sea Secrets


By Alex Bassil
UM News

NorcrossMIAMI, Florida, (January 22, 2016)—Bryan Norcross, a senior hurricane specialist, at The Weather Channel who many Miamians fondly remember as “the voice who talked us through Hurricane Andrew,” opened the 21st annual “Sea Secrets—Exploring Our Oceans 2016” lecture series at the Rosenstiel School of Marine and Atmospheric Science on January 21 by sharing his experiences and a century’s worth of data and research on storms and the effects of El Niño.

Reminding the audience that social media did not exist when Hurricane Andrew hit, the longtime South Florida resident explored his belief that the proliferation of communications platforms will make it more difficult to motivate people living in a hurricane’s path to act and, if necessary, evacuate.

He described a communications paradox, resulting in the highly refined scientific capability to forecast a hurricane’s path but not exactly where the eye will hit. He believes the increasing number of ways to communicate has led to less-accurate information provided to an audience with shorter attention spans. He cited limited news resources and personnel, the lack of land phone lines, fewer credible sources, and more uninformed opinions disseminated about hurricanes and their paths as challenges.

“A dramatic improvement in forecasting science does not equal perfect forecasts,” Norcross said.

Sharing data from 1916 to the present in 50-year increments about hurricane activity and El Niño’s impact on the South Florida peninsula, he asked, “Is this related to climate change? Could this be a positive thing? We don’t know.”

Norcross suggests focusing more communications on the hurricane’s cone of probability, honing the message, and sending it from one source. He warned that younger generations accustomed to navigation apps cannot read a map to know if they are in an evacuation zone. He also warned that many residents haven’t been through a storm and, when the next one hits, the loss of cell phones and closed roadways will complicate the chaos.

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Fish Hatchery Earns Unique Certification

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Fish Hatchery Earns Unique Certification


 Professor Dan Benetti leads the UM Experimental Fish Hatchery

Special to UM News

Fish.Hatchery

Juvenile cobia swim at the Rosenstiel School’s Experimental Fish Hatchery.

MIAMI, Fla. (January 8, 2016) – The Rosenstiel School of Marine and Atmospheric Science’s Experimental Fish Hatchery has made an international mark as the first educational and research institution in the world to obtain the GLOBALG.A.P. Integrated Farm Assurance for Aquaculture for producing cobia eggs and fingerlings commercially.

GLOBALG.A.P. (G.A.P. stands for Good Agriculture Practice) is a Global Food Safety Initiative-recognized scheme at the farm level. The GLOBALG.A.P. Aquaculture Standard applies to a diversity of fish, crustaceans, and molluscs and extends to all hatchery-based farmed species, as well as to the passive collection of seedlings in the planktonic phase. It covers the entire production chain, from broodstock, seedlings, and feed suppliers to farming, harvesting, and processing.

“As a supplier of cobia eggs to Open Blue Sea Farms in Panama, the GLOBALG.A.P. certification is a key element to have in place to support the growth of their business,” said Daniel Benetti, professor of ecosystems and society and director of the aquaculture program at the Rosenstiel School.

“Their commitment to ensuring their innovative farming system has the highest standards through GLOBALG.A.P. and the research support they have provided to our University to develop our cobia selective breeding program made this a natural next step for us. We expect that having this certification will open other doors for us as we move forward.”

The Experimental Fish Hatchery is located on Virginia Key in Biscayne Bay, approximately one mile southeast of downtown Miami. The hatchery is a state-of-the-art facility with capabilities to hold broodstock and conduct research on larval rearing and nursery of several ecologically and economically important species. It supports an innovative academic and research program centered on advanced science and technology to ensure that seafood production through aquaculture is wholesome, environmentally sustainable, socially responsible, and economically viable.

“This aquaculture certification is an extraordinary achievement for the UM Rosenstiel School’s Experimental Fish Hatchery,” said Rosenstiel School Dean Roni Avissar. “The hatchery supports an innovative academic and research program and offers our students a hands-on learning environment where research-to-business takes place.”

Gainesville, Florida-based Quality Certification Services conducted the certification. GLOBALG.A.P. is the world’s leading farm assurance program, translating consumer requirements into Good Agriculture Practice in a rapidly growing list of countries—currently more than 110 worldwide.

 

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