Algemeen

All around him, even in a place as beautiful as the Little Qualicum River estuary, his office for 30 years as a biologist for the Canadian Wildlife Service, he sees the unravelling of "the web of life." "It's happening very quickly," he says. Registered Professional Biologist Neil Dawe has written over 80 papers on birds, ecology and the environment. He received Environment Canada's Regional Citation of Excellence Award for his work in co-founding and co-chairing the Brant Wildlife Festival. He received the Outstanding Service Award from the Federation of B.C. Naturalists and the Ian McTaggart-Cowan Award of Excellence in Biology from the Association of Professional Biologists of B.C. In 2006, he retired from the Canadian Wildlife Service, Environment Canada, after 31 years of managing National Wildlife Areas and Migratory Bird Sanctuaries on Vancouver Island. He is President of the Qualicum Institute: www.qualicuminstitute.ca.

Some 700 species of freshwater fish in North America are in jeopardy, scientists from the U.S., Mexico, and Canada said today. The number represents nearly 40 percent of all freshwater species on the continent and is nearly double the 364 listed as “imperiled” in the previous 1989 study published by the American Fisheries Society. Researchers classified each of the 700 fishes listed as either vulnerable (230), threatened (190), or endangered (280). In addition, 61 fishes are presumed extinct. The new report, published in Fisheries, was conducted by a U.S. Geological Survey-led team of scientists from the United States, Canada and Mexico. “Freshwater fish have continued to decline since the late 1970s" director of the USGS. Groups of fish most at risk are salmon and trout of the Pacific Coast and western mountain regions; minnows, suckers and catfishes throughout the continent; darters in the Southeastern United States; and pupfish, livebearers, and goodeids, a large, native fish family in Mexico and the Southwestern United States. Nearly half of the carp and minnow family and the Percidae (family of darters, perches and their relatives) are in jeopardy, the USGS said in a press statement.

A virus that can cause disease in largemouth bass (Micropterus salmoides) has now been identified in otherwise apparently healthy northern snakeheads (Channa argus) taken from two Potomac River tributaries in Virginia, the U.S. Geological Survey announced today. This is the first time that the pathogen, known as largemouth bass virus, has been reported in northern snakeheads. The virus has been found in bass, sunfish, and other fish species, but largemouth bass are the only species known to develop disease from it. While the significance of this finding is not yet known, the study's lead author, USGS research biologist Luke Iwanowicz, said it raises the possibility that snakeheads could be reservoirs of this virus and capable of transmitting it to bass populations in the Chesapeake Bay watershed. The habitat of the two species overlaps, which may favor transmission of the virus. Little is known about pathogens in northern snakeheads that inhabit U.S. waters. This study, done in cooperation with the Virginia Department of Game and Inland Fisheries, is a preliminary survey of introduced pathogens from northern snakeheads living in Virginia waters. Snakeheads are an invasive, predatory fish species found in the Maryland and Virginia parts of the Chesapeake Bay watershed, in Florida, North Carolina and New England.

Methylmercury (MeHg) is a known neurotoxicant. Emerging evidence indicates it may have adverse effects on the neurologic and other body systems at common low levels of exposure. Impacts of MeHg exposure could vary by individual susceptibility or be confounded by beneficial nutrients in fish containing MeHg. Despite its global relevance, synthesis of the available literature on low-level MeHg exposure has been limited. We undertook a synthesis of the current knowledge on the human health effects of low-level MeHg exposure to provide a basis for future research efforts, risk assessment, and exposure remediation policies worldwide. We reviewed the published literature for original human epidemiologic research articles that reported a direct biomarker of mercury exposure. To focus on high-quality studies and those specifically on low mercury exposure, we excluded case series, as well as studies of populations with unusually high fish consumption (e.g., the Seychelles), marine mammal consumption (e.g., the Faroe Islands, circumpolar, and other indigenous populations), or consumption of highly contaminated fish (e.g., gold-mining regions in the Amazon). Recent evidence raises the possibility of effects of low-level MeHg exposure on fetal growth among susceptible subgroups and on infant growth in the first 2 years of life. Low-level effects of MeHg on neurologic outcomes may differ by age, sex, and timing of exposure. No clear pattern has been observed for cardio-vascular disease (CVD) risk across populations or for specific CVD end points. For the few studies evaluating immunologic effects associated with MeHg, results have been inconsistent. Studies targeted at identifying potential mechanisms of low-level MeHg effects and characterizing individual susceptibility, sexual dimorphism, and non-linearity in dose response would help guide future prevention, policy, and regulatory efforts surrounding MeHg exposure.

EFSA is verantwoordelijk voor de evaluatie van bestaande en nieuwe actieve stoffen van gewasbeschermingsmiddelen die in de EU gebruikt (zullen) worden. Naast het risico voor de menselijke gezondheid buigen de wetenschappers van EFSA zich met de steun van experten uit de lidstaten ook over de milieurisico's. In dat kader werden de voorbije weken nieuwe handleidingen gepubliceerd die op nationaal en Europees niveau een betere risicobeoordeling toelaten voor bijen en waterorganismen. Met die laatsten worden vissen, amfibieën, ongewervelden en planten bedoeld. Vooral de doorbraak in het beoordelen van het gecombineerd risico van blootstelling aan meerdere pesticidenresiduen in voeding springt in het oog. Daarnaast verschijnen er aangepaste handleidingen waarmee pesticiden beter gescreend kunnen worden op hun risico's voor bijen en waterorganismen. Wat de handleiding voor bijen betreft werden specifieke hoofdstukken geschreven voor solitaire bijen en hommels. Het verschil met honingbijen zit hem in de grotere onzekerheid door het gebrek aan juiste sterftecijfers bij populaties solitaire bijen en hommels. Daarom wordt een extra veiligheidsmarge ingebouwd voor het geval deze soorten gevoeliger zouden zijn voor blootstelling aan gewasbeschermingsmiddelen.

In 25 miljoen jaar bouwden ongewervelde zeediertjes voor de noordoostkust van Australië een scherphoekige barrière van meer dan 2600 kilometer lengte en 900 eilanden: het Great Barrier Reef, een ko­raalrif met het oppervlak van Groot Brittannië, ongeveer 344.400 vierkante kilometer. En dit rif weer is een com­plete onderwaterwereld op zich. Zoölogen noemen het voortdurend veranderende, groeiende en bewegen­de Great Barrier Reef niet ten onrechte het grootste levende wezen op aarde. Over zijn hele lengte van 2600 kilo­meter vist ‘het’ met vangdraden en zuigarmen naar buit, slingert het tenta­kels om kleine dieren, slaat het met toeklappende moordenaarsmuil naar vissen, delen poliepen een verse vangst met collega’s van dezelfde koraalkolo­nie. Marinebiologen telden aan het rif rond de 300 koraalsoorten, 4000 mos­selsoorten en meer dan 1500 soorten vissen, waaronder reuzenroggen, ham-en en de grote zwarte Marlijn. Maar het gaat helemaal niet goed met het Australische Great Barrier-koraalrif. De gezondheid van het wereldberoemde natuurmonument is teruggelopen van matig naar slecht. Het Great Barrier Reef heeft de afgelopen jaren onder meer te lijden gehad onder natuurrampen. Zo beschadigde de cycloon Yasi in 2011 grote delen van het grootste rif ter wereld. Het herstel zal waarschijnlijk tientallen jaren duren. Ook slagen pogingen om pesticiden en stikstof in het water terug te dringen maar ten dele.