Diseases
Whale Tales: Cetacean Stranding Response and Medicine in the Pacific Northwest
In January 2012, Joe Gaydos gave a talk at the North American Veterinary Conference in Orlando, FL, entitled, "Whale Tales: Cetacean Stranding Response and Medicine in the Pacific Northwest."
The talk is fairly technical (after all, the audience was all veterinarians), but Joe livened it up with a few videos of exploding whales.
Seriously.
As the whales decompose, gasses build up inside the body cavity. If the pressure isn't released properly, the whale bursts. Sometimes this happens when someone cuts into the carcass (watch video). But it can also happen spontaneously, as with this whale being transported through a city in Taiwan (watch video).
See all the exploding whale videos we collected on our YouTube channel.
Here are a few highlights from the full talk:
"Stranded marine mammal carcasses once were used as food and some of the first laws enacted in New England Colonies were to establish the ownership of beached whale carcasses. Later stranded marine mammals provided animals for museums, live displays and scientific information about little-known species. Today they still provide us with important data on marine mammals and marine mammal populations. Strandings help us to document range expansions for marine mammal species and provide details on marine mammal growth rates, age at maturity, gestation, reproductive season and longevity. Stranded marine mammals also help expand our understanding of marine mammal mortality factors including infectious diseases, toxins and human-caused mortality."
"Strandings have increased from an annual stranding rate of approximately 1.5 cetaceans/year from the 1930’s through the 1970’s to nearly 36 per year from the 1980’s through the current decade. 2 This trend of increased reported strandings corresponds to the formation of a formal stranding network and a heightened interest and dedication by the public and government agencies in reporting and documenting strandings."
"Marine mammals are important sentinel species that tell us about potential negative impacts on animal and marine ecosystem health and ultimately allow us to better understand, manage or mitigate anthropogenic stressors.3 Cetaceans are charismatic species that stimulate great interest in people. They have long life spans, are long-term coastal residents, feed at a high trophic level, and have unique fat stores that can serve as depots for anthropogenic toxins. They also are exposed to environmental stressors such as chemical pollutants, harmful algal biotoxins, and emerging or resurging pathogens, most of which can impact people. Understanding the health of marine mammals ultimately allows us to better conserve their populations, design a healthy ocean and improve and protect human health. Over the past several decades, many important diseases and toxins have been diagnosed in marine mammals that are important to marine mammal conservation and human health or tell us something about the health of our marine ecosystem."
"Veterinarians often play an important role in responding to live and dead stranded cetaceans. For dead animals, they are able to conduct or lead necropsies. When live animals strand, veterinarians help to assess condition determine the level of interaction required and ultimately help treat animals taken into captivity. In 2009 the National Marine Fisheries Service developed a protocol for responding to live marine mammal strandings. These protocols balance the need for standardized procedures while allowing flexibility to address specific needs of different situations for diverse species and habitats, as well as unforeseen circumstances. Veterinarians work with the NMFS and stranding networks to help determine (1) What are the species and group composition involved in the event? (2) Is the situation caused by human activities or a natural event? And (3) Are resources available to ensure the safety and welfare of both the animals and the responders? Intervention can be dangerous for the animals and human responders and response operations are only approved if it will be safe for the animals, stranding responders and the public."
Photo Credit: ShaneAH via Flickr: Creative Commons license
Whale Tales: cetacean stranding and medicine in the Pacific Northwest
2011 Rockfish Recovery Workshop recap
This past week (June 28 & 29, 2011) SeaDoc co-hosted a Rockfish Recovery Workshop in Seattle with the State Department of Wildlife and NOAA Fisheries.
Nearly 100 scientists, fisheries managers, fishers and SCUBA divers attended the 2-day workshop to discuss the current state of knowledge on rockfish and to identify future needs related to recovering depleted rockfish populations in the Salish Sea.
There are 28 species of rockfish in the Salish Sea. Thirteen (13) are listed as species of concern and recently 3 species were listed under the US Endangered Species Act.
In addition to helping organize the workshop, SeaDoc also helped bring in Canadians to share their perspective on what has and has not worked with rockfish recovery on the other side of the border.
A lot of the research SeaDoc funded over the last 10 years was presented and plans were laid for moving rockfish recovery forward. The meeting proceedings will be published soon and will be available here on the SeaDoc website.
In the meantime, here's a recap:
(Please note that this summary is taken from my notes and if there are errors or misstatements they are mine, not the researchers/presenters! -Joe T.)
Historical Context Session
Wayne Palsson spoke on the biology and assessment of rockfishes in Puget Sound. Rockfishes are a diverse group of species with different life histories. They require various habitat during different life stages. They are adapted for slow growth, long survival, late maturity, low natural mortality rates, and high habitat fidelity. These are all factors that make recovery tough. There's a lack of long-term data that makes it hard to create conventional age-structure population models and biomass dynamic models.
Chris Harvey reviewed the ecological history of rockfish exploitation in Puget Sound. Rockfish bones have been found in middens dating back 1,500 years. Much of the fishing pressure on rockfish began after the Boldt decision in 1974, which required that harvests in Puget Sound be coequally managed by the State government and the Treaty Tribes of Washington. It's also been influenced by demographic trends and by the promotion of the fishery by State government. (Unfortunately, as covered in Wayne Palsson's talk, it wasn't until 1982 that scientists learned that rockfish were generally 2 to 3 times longer lived than they'd thought, which meant the existing population models were not accurate.) By the time management efforts were deemed necessary, the greatest harvests had already occurred.
Anne Beaudreau discussed her work to reconstruct historical trends in rockfish abundance. The lack of data on historical populations of rockfish is a major barrier to developing sustainable fisheries. Beaudreau and colleagues interviewed 101 individuals ranging in age from 24 to 90 years to try to derive trends in the abundance of rockfish from 1940 to the present. Of particular interest was the evidence of "shifting baselines." To a statistically significant degree, each age group of respondents interpreted the conditions at the beginning of their awareness as "abundant" and saw declines from there, but what was "declining" to an older person was "abundant" to a younger person.
Benthic Habitat Surveys/Rockfish Abundance Estimates Session
Gary Greene presented the Salish Sea sea floor mapping project, which has produced bathymetric and habitat maps of the San Juan Islands area. Rockfish prefer particular habitat types, and the multibeam echosounders used by Greene and his colleagues allows these potential habitat areas to be identified. (Other participants were very interested in having these maps for other areas in the Salish Sea.
Bob Pacunski spoke on work to use non-lethal methods to survey rockfish populations. Traditional trawl or long-line sampling results in fish mortality, but using a small remotely-operated vehicle has been shown to be effective at providing population surveys.
Stressors Session
Joan Drinkwin of the Northwest Straits Foundation spoke on the threat posed to rockfish by derelict fishing gear, including both nets and traps. The Northwest Straits Initiative has removed 3,860 nets from Puget Sound, all at less than 105 feet deep. There are 950 shallow-water nets still in the water, and at least 70 in deeper water. Based on studies of net mortality by the SeaDoc Society, approximately 1,600 rockfish per year are captured and killed in derelict nets each year in the United States portion of the Salish Sea.
...More coming soon...
Salmonella can kill Killer Whales
New research by SeaDoc and other collaborators has shown that the Salmonella bacteria can be fatal to Killer Whales.
Salmonella Newport Omphaloarteritis in a Stranded Killer Whale (Orcinus orca) Neonate
Wildlife Top 10 in 2010: hot topics, new challenges and promising solutions
Killing with kindness: birdfeeder associated diseases in wild birds
Birding is the one of the leading recreational past times in the United States. In addition to the popularity of bird viewing and species identification, millions of people actively and purposefully attract wild birds to their homes and yards with bird feeders. Commonly encountered species at bird feeders are primarily passerines, and those that are resident in an area may use feeders year- round, especially in winter when weather is harsh and other sources of food are difficult to access. Types of feeders vary from the common tube-shaped seed or nectar feeders, to platform-type structures that hang or sit on a post or on the ground. Feeders are stocked with sunflower seeds, millet, cracked corn, thistle, peanuts, sugar solution, or suet.
Bird feeders can be an important source of nutrition for birds, especially during abnormal or harsh climate or foraging conditions, yet they are man-made constructs and therefore an artificial habitat, promoting repeated congregation of multiple species of birds around a point source of food. Not only may this result in unnatural densities of birds at a given point in time, it can also lead to interactions among and between species that would normally not occur.
PREVENTING DISEASE TRANSMISSION AT BIRD FEEDERS
Keeping bird feeders clean and using fresh food, unused portions of which are changed out regularly, are keys to preventing disease transmission at bird feeders. Feeders should be cleaned at least once a week with 10% bleach solutions. The ground under and around feeders should be swept to remove droppings and unused feed. Water in drinkers or baths should be changed daily.
The type of feeder used has implications for disease transmission as well. Tube feeders that do not accumulate bird droppings the way that platform feeders do may be beneficial in this regard, although studies have shown that tube feeders promote direct contact between birds competing for the limited access points.
To prevent zoonotic potential, people should wear rubber gloves when cleaning. Keeping cats indoors during feeder-associated outbreaks is important for the health of the cats and their owners. During outbreaks of mycoplasmosis or salmonellosis, people should be urged to stop using bird feeders until the epidemic resolves.
Download the complete PDF from which these excertps were taken.
Kirsten V.K. Gilardi, DVM, DACZM School of Veterinary Medicine University of California, Davis, CA
