Vulnerability of sharks as collateral damage in commercial fishing shown by study

A new study that examined the survival rates of 12 different shark species when captured as unintentional bycatch in commercial longline fishing operations found large differences in survival rates across the 12 species, with bigeye thresher, dusky, and scalloped hammerhead being the most vulnerable. The study, led by researchers at the University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science and UM Abess Center for Ecosystem Science and Policy, provides new information to consider for future conservation measures for sharks in the Northwest Atlantic. The unintentional capture of a fish species when targeting another species, known as bycatch, is one of the largest threats facing many marine fish populations.Researchers from UM and the National Marine Fisheries Service analyzed over 10 years of shark bycatch data from the western Atlantic Ocean and Gulf of Mexico tuna and swordfish longline fisheries to examine how survival rates of sharks were affected by fishing duration, hook depth, sea temperature, animal size and the target fish. Some species, such as the tiger shark, exhibited over 95% survival, whereas other species survival was significantly lower, in the 20-40% range, such as night shark and scalloped hammerheads.”Our study found that the differences in how longline fishing is actually conducted, such as the depth, duration, and time-of-day that the longlines are fished can be a major driver of shark survival, depending on the species,” said UM Rosenstiel School Ph.D student and lead author Austin Gallagher. “At-vessel mortality is a crucial piece of the puzzle in terms of assessing the vulnerability of these open-ocean populations, some of which are highly threatened.”The researchers also generated overall vulnerability rankings of species taking into account not only their survival, but also reproductive potential. They found that species most at risk were those with both very slow reproductive potential and unusual body features, such as hammerheads and thresher sharks. The paper’s authors suggest that bycatch likely played an important role in the decline of scalloped hammerhead species in the Northwest Atlantic, which has been considered for increased international and national protections, such as the U.S. Endangered Species List.The researchers suggest that high at-vessel mortality, slow maturity, and specialized body structures combine for the perfect mixture to become extinction-prone.”Our results suggest that some shark species are being fished beyond their ability to replace themselves,” said UM Research Assistant Professor Neil Hammerschlag. “Certain sharks, such as big eye threshers and scalloped hammerheads, are prone to rapidly dying on the line once caught and techniques that reduce their interactions with fishing gear in the first place may be the best strategy for conserving these species.”The study, titled “Vulnerability of oceanic sharks as pelagic longline bycatch” was published online in the open-access journal Global Ecology and Conservation.Story Source:The above story is based on materials provided by University of Miami Rosenstiel School of Marine & Atmospheric Science. Note: Materials may be edited for content and length.

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Intensity of hurricanes: New study helps improve predictions of storm intensity

They are something we take very seriously in Florida — hurricanes. The names roll off the tongue like a list of villains — Andrew, Charlie, Frances and Wilma.In the past 25 years or so, experts have gradually been improving prediction of the course a storm may take. This is thanks to tremendous advancements in computer and satellite technology. While we still have the “cone of uncertainty” we’ve become familiar with watching television weather reports, today’s models are more accurate than they used to be.The one area, however, where there is still much more to be researched and learned is in predicting just how intense a storm may be. While hurricane hunter aircraft can help determine wind speed, velocity, water temperature and other data, the fact is we often don’t know why or how a storm gets stronger or weaker. There has been virtually no progress in hurricane intensity forecasting during the last quarter century.But, thanks to new research being conducted, all that’s about to change.”The air-water interface — whether it had significant waves or significant spray — is a big factor in storm intensity,” said Alex Soloviev, Ph.D., a professor at Nova Southeastern University’s Oceanographic Center. “Hurricanes gain heat energy through the interface and they lose mechanical energy at the interface.”Soloviev is also an Adjunct Professor at the University of Miami Rosenstiel School of Marine and Atmospheric Science (UM RSMAS) and a Fellow at the Cooperative Institute for Marine and Atmospheric Studies (CIMAS.) He and his fellow researchers used a computational fluid dynamics model to simulate microstructure of the air-sea interface under hurricane force winds. In order to verify these computer-generated results, the group conducted experiments at the UM’s Rosenstiel School Air-Sea Interaction Salt Water Tank (ASIST) where they simulated wind speed and ocean surface conditions found during hurricanes.The study “The Air-Sea Interface and Surface Stress Under Tropical Cyclones” was published in the June 16, 2014 issue of the journal Nature Scientific Reports. Soloviev was the lead author of this study, which was conducted by a multi-institutional team including Roger Lukas (University of Hawaii), Mark Donelan and Brian Haus (UM RSMAS), and Isaac Ginis (University of Rhode Island.)The researchers were surprised at what they found. Under hurricane force wind, the air-water interface was producing projectiles fragmenting into sub millimeter scale water droplets. …

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Some characteristics increase the likelihood of getting married and living together

When it comes to romantic relationships, attributes such as health, kindness, and social status have been shown to be important qualities in choosing a partner. It may be surprising to learn, however, that certain personal traits predispose a person towards either getting married or forming a cohabitating relationship.According to a study recently published in the journal Social Science Research, scoring high on attractiveness, personality, and grooming is associated with a greater probability of entering into a marital relationship for both men and women, but it does not collectively have a significant influence on entering a romantic cohabitating relationship.The findings suggest that individuals consider multiple personal characteristics when seeking a long-term partner. Under this scenario, what one finds lacking in a specific area could be overcome with strength in another area.”The findings highlight that Aristotle’s famous quote ‘The whole is more than the sum of its parts’ is pertinent when it comes to personal characteristics and marital arrangements,” says Michael T. French, a professor of Health Economics in the College of Arts and Sciences at the University of Miami (UM), and corresponding author of this study.The study accounts for cohabitation and marriage as competing events in contrast to being single and living without a romantic partner. The project examines three possible outcomes: marriage with or without prior cohabitation, cohabitation without subsequently getting married, and neither marriage nor cohabitation.The results show that 52 percent of married respondents and 51.7 percent of those in cohabiting relationships ending in marriage were rated as above average in physical attractiveness, whereas 45.9 percent of those in a cohabitating relationship without subsequent marriage and 43.6 percent in neither marriage nor cohabitation scored above average on the attractiveness scale. Similar results were found for personality and grooming.Other interesting findings from the study include the following:Women with above average grooming are less likely to cohabit without subsequent marriage. For men, having an above average personality has the strongest association with the likelihood of getting married. Men with above average physical attractiveness have a greater chance of cohabitation without subsequent marriage. “Thus, we have the somewhat curious finding that men with above average looks tend to be more likely to cohabit, while men with above average personalities tend to be more likely to marry (but less likely to cohabit),” the study explains.The study is titled “Personal traits, cohabitation, and marriage.” Co-authors are Ioana Popovici, assistant professor at Nova Southeastern University; Philip K. Robins, professor, School of Business Administration at UM, and Jenny F. …

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Epic ocean voyages of coral larvae revealed

Aug. 20, 2013 — A new computer simulation conducted at the University of Bristol (UB) and University of Miami (UM) Rosenstiel School of Marine & Atmospheric Science has revealed the epic, ocean-spanning journeys travelled by millimetre-sized coral larvae through the world’s seas.The study, published in Global Ecology and Biogeography, is the first to recreate the oceanic paths along which corals disperse globally, and will eventually aid predictions of how coral reef distributions may shift with climate change.Coral reefs are under increasing threat from the combined pressures of human activity, natural disturbances and climate change. It has been suggested that coral may respond to these changing conditions by shifting to more favourable refuges, but their ability to do this will depend on the ocean currents.Sally Wood, a Ph.D. candidate at UB, explains: “Dispersal is an extremely important process for corals. As they are attached to the seafloor as adults, the only way they can escape harmful conditions or replenish damaged reefs is by releasing their young to the mercy of the ocean currents.”Where these intrepid explorers end up is therefore an important question for coral reef conservation. However, tracking the movement of such tiny larvae in the vast oceans is an impossible task. “This is where computer simulation comes in,” adds Wood.Collaborating across the pond, Wood used the Connectivity Modeling System (CMS) developed by Dr. Claire Paris, associate professor of Applied Marine Physics at UM to identify the billions of paths taken. This larval migration model had been tested in a previous study against the reef-building coral Montastraea annularis in the Caribbean, where consensus between modeled estimates of genetic structure were found.”Simulating an unprecedented number of mass spawning events from all known shallow reefs in the global ocean proved essential to identifying critical long dispersal distance events that promote the establishment of new coral colonies. What we found using the CMS are rare long distance dispersers that are thought to contribute to species persistence in isolated coral reefs, and to geographic range shifts during environmental changes,” said Paris.Some of the results yielded by the team were surprising. …

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Specific changes in brain structure after different forms of child abuse

June 1, 2013 — Different forms of childhood abuse increase the risk for mental illness as well as sexual dysfunction in adulthood, but little has been known about how that happens. An international team of researchers, including the Miller School’s Charles B. Nemeroff, M.D., Ph.D., Leonard M. Miller Professor and Chair of Psychiatry and Behavioral Sciences, has discovered a neural basis for this association. The study, published in the June 1 issue of the American Journal of Psychiatry, shows that sexually abused and emotionally mistreated children exhibit specific and differential changes in the architecture of their brain that reflect the nature of the mistreatment.Share This:Researchers have known that victims of childhood abuse often suffer from psychiatric disorders later in life, including sexual dysfunction following sexual abuse. The underlying mechanisms mediating this association have been poorly understood. Nemeroff and a group of scientists led by Christine Heim, Ph.D., Director of the Institute of Medical Psychology at Charité University of Medicine Berlin, and Jens Pruessner, Ph.D., Director of the McGill Center for Studies in Aging at McGill University in Montreal, hypothesized that cortical changes during segments of mistreatment played a role. To study these potential changes, the researchers used magnetic resonance imaging (MRI) to examine the brains of 51 adult women who were exposed to various forms of childhood abuse.The results showed a correlation between specific forms of maltreatment and thinning of the cortex in precisely the regions of the brain that are involved in the perception or processing of the type of abuse. Specifically, the somatosensory cortex in the area in which the female genitals are represented was significantly thinner in women who were victims of sexual abuse in their childhood. Similarly, victims of emotional mistreatment were found to have a reduction of the thickness of the cerebral cortex in specific areas associated with self-awareness, self-evaluation and emotional regulation.”This is one of the first studies documenting long-term alterations in specific brain areas as a consequence of child abuse and neglect,” said Nemeroff, who is also Director of the Center on Aging. …

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