fish

Cytoplasm affects the number of vertebrae in carp-goldfish clones

The March 2005 issue of Biology of Reproduction contains a report of some intriguing findings in cloned offspring created when nuclei from one genus of fish were transplanted to enucleated eggs of another genus of fish. The seven offspring, cloned from nuclei of common carp and egg cytoplasm of goldfish, were virtually identical to the nuclear donor species, Cyprinus carpio, in appearance...

Same mutation aided evolution in many fish species, Stanford study finds

After decades of laboratory work studying how animals evolve, researchers sometimes need to put on the hip waders, pull out the fishing net and go learn how their theory compares to the real world. According to a Stanford University School of Medicine study published in the March 25 issue of Science, Mother Nature is more predictable than lab experiments suggest. In a diverse group of fish...

Zebrafish may hold key to understanding human nerve cell development

Glia appear essential for 'hair cells'responsible for hearing and balance. Traditionally viewed as supportingactors, cells known as glia may be essential for the normal developmentof nerve cells responsible for hearing and balance, according to newUniversity of Utah research. The study is reported in the January 6,2005 issue of Neuron and is co-authored by scientists at the Universityof Was...

Scientists discover how fish evolved to float at different sea depths

Scientists at the University of Liverpool have discovered how fish have evolved over the last 400 million years to stay motionless at different water depths. A research team led by Dr Michael Berenbrink, a Comparative Physiologist at the School of Biological Sciences, has revealed how modern fish, such as pike and cod, have developed a way of floating at certain water levels using a gas-f...

Glow-in-the-dark zebrafish at UH hold keys to biological clocks

Using genetically altered zebrafish that glow in the dark, University of Houston researchers have found new tools that shed light upon biological clock cycles. Gregory M. Cahill, associate professor of biology and biochemistry at UH, and Maki Kaneko, a fellow UH researcher who is now at the University of California-San Diego, presented their findings in a paper titled "Light-dependent Dev...

An (ecological) origin of species for tropical reef fish

Dealing a new blow to the dominant evolutionary paradigm, Luiz Rocha and colleagues from the Smithsonian Tropical Research Institute, Harvard University the University of Florida and the University of Hawaii, report coral reef fish from neighboring habitats may differ more from one another than from fish thousands of miles away. An ecological speciation model for coral reef organisms may spur the...

Mutation in clams protects against paralytic shellfish poisoning but raises human health risk

Just like people, clams can be affected by the toxins that cause paralytic shellfish poisoning (PSP), but scientists have now identified a mutation in clams that gives some protection. PSP toxins interfere with nerve function, and the mutation, which changes a single amino acid in a sodium channel, makes nerves less sensitive to those toxins. The discovery is reported in the April 7 issue...

Research Reveals Functions Of Harmful Shellfish Pathogens

Providing safer shellfish is the goal of Agricultural Research Service (ARS) scientists who are studying the means by which pathogenic bacteria enter shellfish. In the United States, two pathogenic bacteria from the genus Vibrio are of concern: V. vulnificus and V. parahaemolyticus. These bacteria are naturally found in shellfish and seawater, particularly when water temperatures are warm,...

Agilent Technologies introduces advanced zebrafish, mouse microarrays for stem cell and developmental biology research

Which is more likely to happen - you being in a car wreck or being bitten by a shark? Those who answered that cars are greater killers win a free trip to the beach. It's really no contest, says a Texas A&M University professor. Your chances of being in a wreck are far greater than being a shark's lunch, says John McEachran, a professor of wildlife and fishery sciences who has studied...

Scientists discover global pattern of big fish diversity in open oceans

A new study released in Science (via Science Express http://www.sciencexpress.org) on July 28th reveals a striking downward trend in the diversity of fish in the open ocean ?the largest and least known part of our planet. Teasing apart the effects of climate change and fishing over the past 50 years, the authors show a clear link to overfishing and highlight a surprising global pattern of open oc...

Certain fish have a special mating preference

A biologist at Washington University in St. Louis has shown that for some fish species, females prefer males with larger sexual organs, and actually choose them for mating. That does not exclude males with an average-sized sex organ, called a gonopodium. These fish out-compete the larger-endowed males in a predator-laden environment because they have a faster burst speed than the males with large...

Invasive parasite destroying fish species

Assistant Professor Mark Pagani in the Department of Geology and Geophysics at Yale and his colleagues mapped the first detailed history of atmospheric carbon dioxide between 45 - 25 million years ago based on stable isotopes of carbon in a National Science Foundation study reported in Science Express. "Through the energy we consume, each of us makes a contribution to increasing greenhouse...

Crisis in African fish supplies looms, experts warn Africa leaders

32% increase of African fish supply needed by 2020 just to maintain consumption levels Calling fisheries critical for nourishing the poor and for helping Africa cope with the health, economic and social devastation of problems like HIV and AIDS, the New Partnership for Africa's Development (NEPAD), the WorldFish Center and partners are making an urgent appeal to boost the continent's fish...

Temperature regulates circadian clock in zebrafish

The biological clock controls the circadian rhythms of a wide range of physiological and behavioral processes, from fluctuating hormone levels to sleep-wake cycles and feeding patterns. While it's well known that circadian clock elements sense and respond to light cycles, much less is known about how daily temperature cycles affect the clock's timing mechanism in vertebrates. In the open-access...

Jellyfish dominate fish in over-harvested Namibian waters

By sampling sea life in a heavily fished region off the coast of Namibia, researchers have found that jellyfish have actually overtaken fish in terms of the biomass they contribute to this ocean region. The findings represent a careful quantitative analysis of what's been called a "jellyfish explosion" after intense fishing in the area in the last few decades. The findings are reported by Andrew...

Researchers appeal for new regulations to save coral reefs from live fish trade

Researchers are calling for tighter controls on the live reef fish trade, a growing threat to coral reefs, in letters to the international journal Science. <...

Researchers identify new catfish family

They've name...

Helping in a selfish world

Billions of people tuned into recent Live 8 concert broadcasts, some just for the music, others to support the altruistic cause spearheaded by former Boomtown Rat, Sir Bob Geldof. In today's rat-race climate, what makes some of us look out for each other, while others look out for themselves? According to evolutionary theory, natural selection has designed individuals to behave selfishishl...

Ships bring alien jellyfish invaders to our shores

Marine environments around the world are being threatened by exotic species of the moon jellyfish being dispersed by international shipping, according to new research. Using genetic data and computer simulations of ocean currents and water temperatures, researchers from the University of New South Wales and the University of California, Davis, have revealed that the moon jellyfish could no...

Vibrio bacteria could be a risk to fish as well as humans

About half of new marine vibrio bacteria discovered in the last five years, can kill fish and crustacea, according to researchers at Heriot-Watt University in Edinburgh. The most common disease of vibrios is cholera, which has caused millions of cases of illness and fatality in humans. Recent interest in this genus of bacteria has led to the discovery of many new species, especially from s...

Fish and chips: A fast track to understanding blood development

Researchers at the University of Minnesota have identified for the first time a group of genes that impact the development and function of blood stem cells, a discovery that brings researchers a step closer to harnessing the power of stem cells for disease treatments. Every day, blood stem cells divide and differentiate to generate approximately 200 billion new blood cells in the bone marr...

How fish hear and make sounds at same time

Cornell University researchers have learned how a common fish found along the West Coast can hum and hear outside sounds at the same time. The study marks the first time that scientists have found a direct line of communication between the part of a vertebrate's brain that controls the vocal muscle system and the part of the ear that hears sound. The researchers believe that understanding...

Zebrafish may hold key to improved cancer research

A new study has confirmed that research done with zebrafish may be able to play a critical role in learning about the genetic basis of cancer and the mutations that can lead to it - and identified one gene in particular, B-myb, whose function is essential to preventing tumors. The findings were published in a professional journal, Proceedings of the National Academy of Sciences, by researc...

Sudden change in social status triggers genetic response in male fish, study finds

Throughout the animal kingdom, rival males routinely challenge one another for the right to reproduce. From the head-on collisions between bighorn rams to the ritualized wrestling matches of male rattlesnakes, combat is often the key to reproductive success. But now scientists studying a species of African cichlid fish have discovered that low-ranking male cichlids can quickly become lead...

Fish evolve a longer lifespan by evolving a longer reproductive period, researchers find

A UC Riverside-led research team has found that as some populations of an organism evolve a longer lifespan, they do so by increasing only that segment of the lifespan that contributes to "fitness" ?the relative ability of an individual to contribute offspring to the next generation. Focusing on guppies, small fresh-water fish biologists have studied for long, the researchers found that gu...

Tsunami + 1 year: Reviving exhausted fisheries should trump replacing boats, gear, experts say

One year after a tsunami devastated South Asian communities, global fisheries experts say habitat restoration, retraining and education programs are much needed to revive severely exhausted fisheries and steer survivors into more sustainable livelihoods than fishing. According to new analyses by the Malaysia-based WorldFish Centre (see ? Rebuilding Boats May Not Equal Rebuilding Livelihood...

Multiple genes permit closely related fish species to mix and match their color vision

Vision, like other biological attributes, is shaped by evolution through environmental pressures and demands, and even closely-related species that are in other ways very similar might respond to their particular environments by interpreting the visual world slightly differently, using photoreceptors that are attuned to particular wavelengths of light. By studying a special group of closely-relat...

Envisat radar surveillance protects endangered prehistoric fish

A satellite surveillance zone within the southern Indian Ocean is helping protect the endangered Patagonian toothfish from pirate fishing vessels. Perched between Africa, India, Australia and Antarctica, the windswept French territory of the Kerguelen Islands is one of the remotest places on Earth. Even so, fishing vessels are lured there by the prospect of catching one valuable species fo...

Older female fish prefer imperfect male mates, study finds

There's hope for the less-than-perfect male ?if you're a swordtail fish, that is. As the size and age of female swordtail fish increase, so does the preference for males with asymmetrical markings, according to a new Ohio University study. Molly Morris, associate professor of biological sciences, and colleagues found that older female swordtails spent more time with asymmetrically striped...

Genetic analysis of cavefish reveals more about evolution

A multi-institutional study offers additional insight into the evolutionary process by examining how albinism evolves in cavefish. Researchers, including New York University Biology Professor Richard Borowsky, examined two populations of Mexican cavefish and found that albinism in both populations was linked to Oca2--a pigmentation gene also responsible for the most common form of albinism in hu...

Changes to embryos can elicit change in adult fish

In a study illustrating the apparent linkages between the evolutionary development and embryonic development of species, researchers have uncovered the genetic elements that determine the structure and function of a simple biomechanical system, the lower jaw of the cichlid fish. In addition, they've shown that increasing expression of a particular gene in an embryo can lead to physical changes in...

Overfishing may drive endangered seabird to rely upon lower quality food

The effects of overfishing may have driven marbled murrelets, an endangered seabird found along the Pacific coast, to increasingly rely upon less nutritious food sources, according to a new study by biologists at the University of California, Berkeley. The results, to be published online by early March 2006 in the journal Conservation Biology, suggest that feeding further down the food web...

Fossil find: 'Godzilla' crocodile had head of a dinosaur, fins like a fish

At the southern tip of South America , they found fossils of an entirely new specie...

Overfishing in inland waters reduces biodiversity and threatens health

Systematic overfishing of fresh waters occurs worldwide but is largely unrecognized because of weak reporting and because other pressures can obscure fishery declines, according to an article in the December 2005 issue of BioScience. Although the status of inland waters and their fish species should be of broad concern, threats to freshwater fisheries and associated biodiversity have recei...

Ocean 'dead zones' trigger sex changes in fish, posing extinction threat

Oxygen depletion in the world’s oceans, primarily caused by agricultural run-off and pollution, could spark the development of far more male fish than female, thereby threatening some species with extinction, according to a study published today on the Web site of the American Chemical Society journal, . The study is scheduled to appear in the May 1...

There's something fishy about human brain evolution

Forget the textbook story about tool use and language sparking the dramatic evolutionary growth of the human brain. Instead, imagine ancient hominid children chasing frogs. Not for fun, but for food. According to Dr. Stephen Cunnane it was a rich and secure shore-based diet that fuelled and provided the essential nutrients to make our brains what they are today. Controversially, according...

Mechanism for memory revealed in neurons of electric fish

Researchers from The University of Texas at Austin studying electric fish have gained new insight into how memory is stored at the level of neurons. Dr. Harold Zakon, Dr. Jörg Oestreich and colleagues show that when electr...

Hooked on fishing, and we're heading for the bottom, says scientist

The world has passed "peak fish" and fishermen's nets will be hauling in ever diminishing loads unless there's political action to stem the global tide of over fishing, says a fisheries expert based at the University of British Columbia. Dr. Daniel Pauly says the crisis in the world's fisheries is less about scientific proof than about attitude and political will. And, he says, the world'...

Thin tough skin, slow-growing gills protect larval Antarctic fish

Very thin but hardy, unblemished skin and slow developing gills appear to be keys to survival for newly hatched Antarctic notothenioids, a group of fish whose adults thrive in icy waters because of antifreeze proteins (AFPs) in their blood. Such adaptations are important, researchers at the University of Illinois atUrbana-Champaign say, because the larval fish of at least two species of no...

Cuttlefish masters of disguise despite colorblindness

Cuttlefish are wizards of camouflage. Adept at blending in with their surroundings, cuttlefish are known to have a diverse range of body patterns and can switch between them almost instantaneously. New research from MBL Marine Resources scientists, to appear in the May 2006 issue of the journal Vision Research, confirms that while these masters of disguise change their appearance based on visual...