Constantine Alexander's blog

Do dolphins think nonlinearly?

		This is professor Tim Leighton. Credit: University of Southampton

Research from the University of Southampton, which examines how dolphins might process their sonar signals, could provide a new system for man-made sonar to detect targets, such as sea mines, in bubbly water.

When hunting prey, dolphins have been observed to blow 'bubble nets' around schools of fish, which force the fish to cluster together, making them easier for the dolphins to pick off. However, such bubble nets would confound the best man-made sonar because the strong scattering by the bubbles generates 'clutter' in the sonar image, which cannot be distinguished from the true target.

Taking a dolphin's sonar and characterising it from an engineering perspective, it is not superior to the best man-made sonar. Therefore, in blowing bubble nets, dolphins are either 'blinding' their echolocation sense when hunting or they have a facility absent in man-made sonar.

The study by Professor Tim Leighton, from the University's Institute of Sound and Vibration Research (ISVR), and colleagues examined whether there is a way by which dolphins might process their sonar signals to distinguish between targets and clutter in bubbly water.

In the study, published in Proceedings of the Royal Society A, Professor Leighton along with Professor Paul White and student Gim Hwa Chua used echolocation pulses of a type that dolphins emit, but processed them using nonlinear mathematics instead of the standard way of processing sonar returns. This Biased Pulse Summation Sonar (BiaPSS) reduced the effect of clutter by relying on the variation in click amplitude, such as that which occurs when a dolphin emits a sequence of clicks.

		This is professor Tim Leighton and dolphin. Credit: University of Southampton

Professor Leighton says:

"We know that dolphins emit sequences of clicks and the amplitude of each click can vary from one to the next, so that not all the clicks are the same loudness. We asked, what if this variation in amplitude was not coincidental, but instead was key to distinguishing fish from bubbles.

"These clicks were shown to identify targets when processed using nonlinear mathematics, raising the question of whether dolphins also benefit from such mathematics. The variation in amplitude of these clicks is the key: it produces changes in the echoes which can identify the target (fish) in the bubble net, where man-made sonar does not work.

"Although this does not conclusively prove that dolphins do use such nonlinear processing, it demonstrates that humans can detect and classify targets in bubbly water using dolphin-like sonar pulses, raising intriguing possibilities for dolphin sonar when they make bubble nets."

BiaPSS was shown to be effective in distinguishing targets from the clutter generated by bubbles in the 'field of view' of the sonar. One such target is a sea mine, which is relatively simple to purchase, and inexpensive (around $1,000 each) compared to the financial damage (let alone injury and loss of life) that they cause (for example $96 million repair to USS Samuel B Roberts; $24 million repair to USS Princeton; $3.6 million to USS Tripoli).

Professor Leighton adds:

"There are still questions to answer. For one thing, dolphins would have to use a frequency, when they enter bubbly water, which is sufficiently low that they can hear up to frequencies twice as high in pitch. Until measurements are taken of wild dolphin sonar as they hunt in bubbly water, these questions will remain unanswered. What we have shown is that it is not impossible to distinguish targets in bubbly water using the same sort of pulses that dolphins use."

The authors previously proposed a form of sonar signal (TWIPS: Twin Inverted Pulse Sonar) that could work in bubble clouds, consisting of pairs of pulses that were identical except that one was inverted with respect to the other, that could detect targets in bubbly water if the signal processing were to make use of nonlinear mathematics. However, while these TWIPS pulses were successful, there was no conclusive evidence that the types of pulses devised for that study are used by any type of dolphin.

Contact: Glenn Harris
G.Harris@soton.ac.uk
44-238-059-3212
University of Southampton

Promiscuous squid fatigued after mating

		Pictured are a southern dumpling squid male (left) and female. Credit: Mark Norman

In order to pass on their genes, southern dumpling squid engage in up to three hours of mating with each partner, but University of Melbourne researchers have found that this results in a reduced ability to swim for up to 30 minutes afterwards.

The research provides new insight into the evolution of reproductive strategies and behaviours and is the first time that the energetic costs of mating have been shown to affect physical abilities after mating.

The research was conducted by Master of Science student Ms Amanda Franklin with Ms Zoe Squires and Dr Devi Stuart-Fox from the Department of Zoology at the University of Melbourne, and is published today [Wednesday 18 July] in the international journal Biology Letters.

The team studied dumpling squid (Euprymna tasmanica) that live in waters of Southern Australia including Port Phillip Bay and Tasmania and reach about 7cm long at adult size.

Dumpling squid engage in up to three hours of mating and males appear to initiate mating whenever the opportunity arises. The male grabs the female from underneath, and holds her in place throughout copulation. Both males and females can change colour from a sandy yellow to dark purple with green and orange highlights. They can also produce a cloud of ink as a decoy to help them escape from predators.

Ms Franklin said the team was keen to understand the impact of such an extensive mating ritual because although traditionally thought to be trivial, the energetic costs of mating could reduce an animal's survival if it decreased the ability to avoid predators and forage for food.

The researchers collected dumpling squid from St Leonards in south-eastern Australia and tested their swimming endurance against a constant current of water in the lab. The squid were then allowed to mate and their swimming ability re-tested.

"We found that after mating, both male and female dumpling squid took up to thirty minutes to recover to their previous swimming ability," Ms Franklin said.

"This suggested that the squid were suffering from temporary muscle fatigue."

"Our results were a little surprising as the degree of fatigue was similar in both genders even though mating looks more strenuous for males."

"We predict that during this phase of muscle fatigue, squid may hide in the sand to avoid predators until they have recovered. The cost to them in doing this of course is that they cannot forage for food or search for other mates at this time."

Dumpling squid are closely related to about 10 bobtail squid species found around the world, including the waters around Hawaii and the South China Sea. These species have similar mating habits to the southern dumpling squid.

"Dumpling squid live for less than a year, and may engage in the energetic activity of mating many times within their short breeding period. This reproductive strategy may have other costs to individuals besides energy loss and we have investigated this further by assessing the effect of mating on female lifespan. We're hoping to report the results of this experiment very soon."

Contact: Nerissa Hannink
nhannink@unimelb.edu.au
61-430-588-055
University of Melbourne

Swimming across the Mediterranean and the Black Seas

New report by experts on the status of seals, sea turtles, porpoises, dolphins and whales now available

The conservation status of the marine mammals and sea turtles that inhabit the Mediterranean and Black Seas has been a subject of concern and interest for many years. The species analysed in this report, previously classified by IUCN at global level, show for the first time the regional status for those cetacean species resident in the Mediterranean Sea, presenting a more endangered status as compared with their global standing. The only seal species (Monachus monachus) and the two sea turtles (Chelonia mydas and Dermochelys coriacea) found in the region are also featured in this report.

Out of the 87 cetacean species existing worldwide (whales, dolphins and porpoises), 21 species and three subspecies have been sighted in the Mediterranean and Black Seas. Eight of these have regular populations in the Mediterranean, three subspecies are endemic to the Black Sea (i.e. not found anywhere else in the world) and 12 are visitors and appear from time to time in the Mediterranean. However, information for many of them is still patchy and limited to few areas. Furthermore, the status of marine turtles and the only seal in the region are highly endangered.

“This compilation, including illustrations and distribution maps, should give governments, environmental activists and all those interested in Mediterranean biodiversity a starting point for identifying, and deciding how and where to allocate limited resources as they try to restore and prevent additional harm to marine ecosystems and species which are still, quite literally, in danger of extinction.” comments Maria del Mar Otero, IUCN Mediterranean Marine Programme officer.

Of the 9 resident species of marine mammals (8 cetaceans and the Monk seal) assessed using the IUCN Red List Criteria, 6 (66%) are threatened with extinction (CR, EN, VU), amongst which the Mediterranean Monk seal, the Sperm Whale (Physeter macrocephalus) and the Short-beaked Common Dolphin (Delphinus delphis). Craig Hilton Taylor, IUCN Red List Unit Manager, comments “This data comes from the latest assessment of The IUCN Red List of Threatened Species™, the world's most comprehensive inventory of the global conservation status of plants, animals and fungi and the most authoritative guide to the status of biological diversity. Complemented by information from specialist groups, and produced to reach wider audiences, we hope this new publication will help to know our marine species better, and to increase general awareness on their threats and conservation measures needed to preserve them, as well as the need for further research on marine species”.

The study assessed all populations of Mediterranean and Black Sea cetaceans against the IUCN Red List Categories and Criteria. The IUCN Red List Authority, Species Survival Commission members, Species Programme, and the Agreement on the Conservation of Cetaceans of the Black Sea, Mediterranean Sea and Contiguous Atlantic Area (ACCOBAMS) have also contributed to the review and enrichment of the data presented in the report. Financial support was provided by the MAVA Foundation and the Spanish Agency for International Development Cooperation (AECID).

This new publication will be launched on the occasion of the Third Meeting of National Correspondents of the Strategic Action Programme for the Conservation of Biological Diversity in the Mediterranean Region (SAP BIO) / MedMPAnet Project Mid-term Workshop to be held in Málaga from 4 to 6 July 2012, organised by the Regional Activity Centre for Specially Protected Areas (RAC/SPA) with the support of the Spanish Ministry of Agriculture, Food and Environment and the IUCN Centre for Mediterranean Cooperation.

Related Links:

• Download the report: Marine mammals and sea turtles of the Mediterranean and Black Seas
• IUCN Mediterranean marine programme
• IUCN Mediterranean Species Programme
• IUCN Specialist Groups

NOAA collects 50 metric tons of marine debris from Northwestern Hawaiian Islands

NOAA collected nearly 50 metric tons of marine debris, which threatens monk seals, sea turtles and other marine life in the coral reef ecosystem, in the Northwestern Hawaiian Islands. Credit: NOAA

NOAA Ship Oscar Elton Sette arrived back in its homeport of Honolulu on Saturday after a month in Papahānaumokuākea Marine National Monument. The team of 17 scientists collected nearly 50 metric tons of marine debris, which threatens monk seals, sea turtles and other marine life in the coral reef ecosystem, in the Northwestern Hawaiian Islands (NWHI). NOAA has conducted annual removal missions of marine debris in the NWHI since 1996 as part of a coral restoration effort.

“What surprises us is that after many years of marine debris removal in Papahānaumokuākea and more than 700 metric tons of debris later, we are still collecting a significant amount of derelict fishing gear from the shallow coral reefs and shorelines,” said Kyle Koyanagi, marine debris operations manager at NOAA Fisheries’ Pacific Islands Fisheries Science Center and chief scientist for the mission. “The ship was at maximum capacity and we did not have any space for more debris.”

Scientists load boats with marine debris collected at Midway Atoll in Papahānaumokuākea Marine National Monument. Credit: NOAA

This year, marine debris was collected from waters and shorelines around northern most islands and atolls: Kure Atoll, Midway Atoll, Pearl and Hermes Atoll, Lisianski Island and Laysan Island. Approximately half of the debris was comprised of derelict fishing gear and plastics from Midway Atoll’s shallow coral reef environments, where the team also completed a 27-day land-based mission prior to loading debris on the 224-ft. NOAA Ship Oscar Elton Sette.

As part of this year’s mission, the NOAA team did look for debris from the 2011 tsunami in Japan, however, no debris with an explicit connection to the tsunami was found. Scientists monitored marine debris for radiation in partnership with the Hawaii Department of Health out of abundance of caution and to gather baseline data from the NWHI.

“While we did not find debris with an obvious connection to last year’s tsunami, this mission was a great opportunity to leverage activities that had already been planned and see what we might find,” said Carey Morishige, Pacific Islands regional coordinator for NOAA’s Marine Debris Program. “It’s also an important reminder that marine debris is an everyday problem, especially here in the Pacific.”

NOAA divers cut a Hawaiian green sea turtle free from a derelict fishing net during a recent mission to collect marine debris in the Northwestern Hawaiian Islands. Credit: NOAA

A portion of the funding for this year’s marine debris removal activities was provided as part of the legal settlement collected by NOAA’s Damage Assessment, Remediation and Restoration Program from a July 2005 ship grounding at Pearl and Hermes Atoll in the Monument. Additional support was provided by NOAA’s Marine Debris Program, NOAA Fisheries’ Pacific Islands Fisheries Science Center and Papahānaumokuākea Marine National Monument, as well as other partners including U.S. Fish and Wildlife Service, the State of Hawaii, U.S. Coast Guard, Schnitzer Steel, and Covanta Energy.

Marine debris removed during this project will be used to create electricity through Hawaii’s Nets to Energy Program, a public-private partnership. Since 2002, more than 730 metric tons of derelict nets have been used to create electricity — enough to power nearly 350 Hawai‘i homes for a year.

NOAA’s mission is to understand and predict changes in the Earth's environment, from the depths of the ocean to the surface of the sun, and to conserve and manage our coastal and marine resources.

NOAA, partners meet to explore climate change and coastal tribes

A crew in a traditional Northwest Canoe approaches the Hoh River on the Olympic Peninsula in Washington. Ocean canoes of the Northwest are made from Western red cedar trees as old as 1,000 years. Their great size and abundance made the Northwest Canoe culture possible. Credit: NOAA

How climate change affects U.S. indigenous coastal cultures is the focus of the First Stewards symposium starting today at the Smithsonian National Museum of the American Indian in Washington, D.C. The coastal treaty tribes of Washington state – the Hoh, Makah, Quileute tribes and the Quinault Indian Nation – are hosting the event and collaborating with NOAA and other partners.

Native leaders, including American Indians, Alaska Natives and Pacific Islanders, will join climate scientists, policy-makers, and representatives of non-government organizations to discuss ways indigenous peoples and cultures may be able to increase their ability to adapt to predicted climate change. Participants also will discuss how to include indigenous traditional knowledge in U.S. climate change science, education, and governance.

“Coastal indigenous people have thousands of years of rich, place-based knowledge of climate change and its effects on humans, and how to adjust to these changes,” said Daniel J. Basta, director, NOAA’s Office of National Marine Sanctuaries. “Their experience is extremely valuable today and can help all of us as the world looks for ways to adapt.”

The Office of National Marine Sanctuaries manages a national system of marine protected areas where local indigenous communities participate in management of marine resources.

“We need everyone engaged in working on adaptations, mitigation, strategies, and solutions to climate change,” said Micah McCarty, chairman of the Makah and of the First Stewards organizing committee. “Even the polar bears and people of the Arctic Circle cannot escape the second-hand smoke of the vehicle tailpipe and the smokestack that leave such a large carbon footprint.”

“Coastal Indian people are already dealing with the effects of climate change,” said Billy Frank Jr., chairman of the Northwest Indian Fisheries Commission. “The glaciers that feed our life-giving rivers are melting. Reservations are flooding more often, forcing some tribes to have to move their homes to higher ground. Tribes are the natural choice to lead the nation in the response to climate change.”

The symposium, which runs from July 17 through the 20th, is being held in partnership with scientific, tribal, governmental and non-governmental organizations, including the Smithsonian National Museum of the American Indian, NOAA’s Office of National Marine Sanctuaries, NOAA’s National Marine Fisheries Service, The Nature Conservancy, Northwest Indian Fisheries Commission and the Western Pacific Regional Fishery Management Council.

Other partners include Salmon Defense, National Congress of American Indians, United South and Eastern Tribes, Uncas Consulting Services, and EA Engineering, Science, and Technology.

NOAA’s mission is to understand and predict changes in the Earth's environment, from the depths of the ocean to the surface of the sun, and to conserve and manage our coastal and marine resources.

Developing policy on moving threatened species called 'a grand challenge for conservation'

Social, legal, and ethical complications of relocating species to save them need consistent consideration

Managed relocation—the act of purposely relocating a threatened species, population, or genotype to an area that is foreign to its natural history—is a controversial response to the threat of extinction resulting from climate change. An article in the August 2012 issue of BioScience by Mark W. Schwartz and his colleagues reports on the findings of the Managed Relocation Working Group, an interdisciplinary group of scientists, researchers, and policymakers whose goals were to examine the conditions that might justify the use of managed relocation and to assess the research being conducted on the topic. The authors note that although traditional management strategies are not likely to address the effects of climate change adequately, guidelines and protocols for managed relocation are poorly developed. "Developing a functional policy framework for managed relocation is a grand challenge for conservation," they assert.

Moving a species to a higher elevation, for instance, may allow it to survive rising temperatures or an elevated sea level, but doing do in an ethically acceptable way is fraught with both legal and political complications. Unforeseen environmental consequences of such an action may be severe—the species might become invasive in its new location, for example. Some question the appropriateness of conserving a single species at the expense of possibly disrupting an entire ecosystem. What is more, lax regulation of managed relocation may open the door to exploitative movement of species. Regulation is often dispersed among states, the federal government, and various agencies, which may have conflicting agendas, and most relevant policies and laws were not written with climate change in mind.

The current state of ecological knowledge is such that predicting accurately the effects of any particular proposed relocation is difficult and likely to remain so for the foreseeable future. This makes it hard to know which species are most likely to benefit from managed relocation. Even so, ad hoc managed relocation projects are already under way in the United States and the United Kingdom.

Schwartz and colleagues recommend action by government agencies to develop and adopt best practices for managed relocation. They urge a transparent approach, with integrated research and international involvement of scientists, policymakers, resource managers, and other stakeholders. The BioScience authors provide a list of key questions that identify the main areas of possible contention. What is needed, they write, is more research to make better predictions; clearly written policies to define the responsibilities of various parties, to enable management and to limit abuse; and stakeholder involvement to minimize social conflict.

Reference: Managed Relocation: Integrating the Scientific, Regulatory, and Ethical Challenges.
Mark W. Schwartz, Jessica J. Hellmann, Jason M. McLachlan, Dov F. Sax, Justin O. Borevitz, Jean Brennan, Alex E. Camacho, Gerardo Ceballos, Jamie R. Clark, Holly Doremus, Regan Early, Julie R. Etterson, Dwight Fielder, Jaqueline L. Gill, Patrick Gonzalez, Nancy Green, Lee Hannah, Dale W. Jamieson, Debra Javeline, Ben A. Minteer, Jay Odenbaugh, Stephen Polasky, David M. Richardson, Terry L. Root, Hugh D. Safford, Osvaldo Sala, Stephen H. Schneider, Andrew R. Thompson, John W. Williams, Mark Vellend, Pati Vitt, and Sandra Zellmer

BioScience, published monthly, is the journal of the American Institute of Biological Sciences (AIBS). BioScience is a forum for integrating the life sciences. It publishes commentary and peer-reviewed articles. The journal has been published since 1964. AIBS is a meta-level organization for professional scientific societies and organizations that are involved with biology. It represents nearly 160 member societies and organizations.

Contact: Tim Beardsley
tbeardsley@aibs.org
703-674-2500 x326
American Institute of Biological Sciences

Lowering the national ozone standard would significantly reduce mortality and morbidity

The Science of Ozone Hole. University of Cambridge

Establishing a more stringent ozone standard in the U.S. would significantly reduce ozone-related premature mortality and morbidity, according to a new study published online July 18 in the journal Environmental Health Perspectives.

"Abundant evidence links exposure to ozone with adverse health effects, including impaired pulmonary function, asthma exacerbations, increased hospital and emergency room visits, and increased mortality, yet the current National Ambient Air Quality Standard of 75ppb is often exceeded," said lead author Jesse Berman, a PhD candidate at Johns Hopkins Bloomberg School of Public Health. "Our study shows that adhering to the current standard would result in a significant reduction in morbidity and mortality and, furthermore, that applying even more stringent ozone standards would result in even greater reductions."

The research was supported in part by an American Thoracic Society research contract to Mr. Berman.

Using national ozone monitoring data for 2005-07 and concentration-response data obtained or derived from the epidemiological literature, the authors applied health impact assessment methodology using the Environmental Benefits Mapping and Analysis Program (BenMAP) to estimate the numbers of deaths and other adverse health outcomes that would have been avoided during this time period if the current eight-hour average ozone standard (75ppb) or lower standards had been met.

The researchers estimated that if the current ozone standard of 75ppb had been met, 1,410 to 2,480 ozone-related premature deaths would have been avoided during the study period. At a lower standard of 70ppb, 2,450 to 4,130 deaths would have been avoided, and at a standard of 60ppb, 5,210 to 7.990 deaths would have been avoided. At the 75ppb standard, acute respiratory symptoms would have been reduced by three million cases and school-loss days by one million cases annually. Even greater avoided mortalities and morbidities would have been achieved at 70ppb and 60 ppb standards.

"The EPA's Clean Air Scientific Advisory Committee has recommended adoption of an ozone standard in the 60 to 70 ppb range," said Mr. Berman. "Our analysis shows that implementing such a lower standard would result in substantial public health benefits."

Contact: Nathaniel Dunford
ndunford@thoracic.org
212-315-8620
American Thoracic Society

Refining the tool kit for sustainable fisheries

Managers who have more -- and more subtle – tools may be able to generate more profit from a sustainable fishery than they can using marine protected areas alone

As spatial planning is used increasingly to manage fisheries and other ocean resources, researchers are working to determine the best ways to use and refine the various spatial management tools. Among them are marine protected areas (MPAs), one of the most common methods, which limit or entirely curtail fishing in a given area.

A new paper published in the early edition of the Proceedings of the National Academy of Sciences (USA) on July 2 describes research in this area conducted by UCSB Marine Science Institute project scientist Andrew Rassweiler and co-principal investigators Christopher Costello, Bren professor of resource economics, and David Siegel, professor in the UCSB Geography Department and director of the Earth Research Institute.

According to Rassweiler, considerable research has focused on the ability of MPAs to increase fishery returns, but the potential for a broader range of spatial management approaches to outperform MPAs has received far less attention.

The team wanted to determine whether a fishery might be more profitable if a manager had access to tools other than MPAs, such as zoning (for fishing, energy, recreation, etc.) or spatial user rights, which would affect the distribution of fishing effort in a more nuanced manner.

They used bioeconomic models of seven near-shore fisheries in Southern California to explore the value of optimized spatial management in which the distribution of fishing is chosen solely to maximize profits.

They were able to show that, given the right circumstances, fully optimized spatial management employing a blend of management strategies, including but is not limited to establishing MPAs, can substantially increase fishery profits relative to an optimal non-spatial management in which the amount of fishing is regulated, but not its spatial distribution.

Strategically placed MPAs, they found, can also increase profits substantially compared with non-spatial management strategies; however, profit increases available through optimal use of MPAs only are roughly half those to be realized from fully optimized spatial management using a suite of management tools in addition to MPAs.

Further, MPAs must be placed carefully. Placed randomly, the researchers found, profits dropped. Thus, the higher profits resulting from spatial management strategies can only be achieved if the fishery is well understood and regulations are strategically designed.

"If you gave a manager a variety of management tools, how much could that manager increase profits in his fishery," says Rassweiler in defining the core research question.

The methodology involved modeling the results of three different distinctive management scenarios. In the simplest scenario, the manager is doing a great job of setting the total amount of effort, for example, by placing limits on the number of boats participating in the fishery or the number of days they are allowed to fish, but doesn't tell anyone where to go. In the most complex version, the manager tells everyone exactly how much they can fish in each location. And in a third, intermediate, scenario, which, Rassweiler says, is closest to actual practice, spatial management comes in the form of no-take MPAs, so that the manager can tell people how much to fish overall while also closing designated areas to fishing.

The limitation of the intermediate scenario, says Rassweiler, "is that it's a pretty blunt tool. The manager isn't able to add nuance by saying, 'You can fish there, but only a little bit.' An area is either open to fishing or it's not."

"What we've shown is first, that it's really valuable to give managers more tools, and second, that MPAs are a partial, less-nuanced tool that can get about half the profits as the most valuable tool. But a lot of science has to be done to decide exactly which method to use in a real fishery, and more knowledge has to go into setting spatial regulations than non-spatial ones, because a lot of spatial data is needed," says Rassweiler. "One question we ask but don't really finish answering in this project is, Is the extra effort worth the cost associated with it? Well, it could be if the resulting profits are much higher."

Rassweiler describes MPAs as "almost a silver bullet from a conservation perspective," because if a habitat-rich area is closed to fishing, the fish population will increase. "It's a pretty low bar to enhance conservation using MPAs," he says. "It's a much higher bar to use them as a fishing management tool."

Contact: Andrew Rassweiler
andrew.rassweiler@lifesci.ucsb.edu
University of California - Santa Barbara