Background Articles

Once one of the most common cetaceans in the Mediterranean Sea, the short-beaked common dolphin has declined throughout the region since the 1960s and in 2003 this population was classified as Endangered in the International Union for Conservation of Nature (IUCN) Red List. Here, we document the species’ precipitous decline in eastern Ionian Sea coastal waters across 13 yr. While 150 animals were present in the study area (1050 km2) in 1996, only 15 were observed in 2007. A 12 mo assessment of fishing effort and catch, together with circumstantial evidence, suggests that the decline was caused largely by prey depletion resulting from overfishing. We analyzed the impacts of various fishing gear and estimated the degree of resource overlap between common dolphins and local fisheries. The total biomass removed annually by 308 fishing boats in the study area averaged 3571 t, while that consumed by common dolphins was 17 t. Resource overlap between common dolphins and fisheries—expressed as an average Pianka index of 0.5—differed according to fishing gear, being higher for purse seiners (0.7) and beach seiners (0.4) and lower for bottom trawlers (0.1), trammel boats (0.2) and longliners (0.0). Only about 10 active purse seiners (4% of the total active fishing fleet) were responsible for 33% of the biomass removal, and likely had the greatest impact on prey of common dolphins. This study indicates a high risk of local disappearance of common dolphins in the very near future, unless fishery management measures are implemented immediately. Purse seining should be the main management target.

Phytoplankton blooms are increasingly conspicuous along the world's coastlines, and the toxic effects of these blooms have become a major concern. Nutrient enrichment often causes phytoplankton blooms, which decrease water transparency, but little is known about the effects of such light regime changes on whole communities of the continental shelf. A series of simulations designed to evaluate the potential effects of shading by phytoplankton blooms on community organization were conducted using a balanced trophic model of the West Florida Shelf ecosystem and the Ecopath with Ecosim modeling approach. Many functional groups in the system were predicted to decline as benthic primary production was inhibited through shading by phytoplankton, especially when associated biogenic habitat was lost. Groups that obtain most of their energy from planktonic pathways increased when shading impact and associated structural habitat degradation were complemented by enhanced phytoplankton production. Groups predicted to decline as the result of shading by plankton blooms include seabirds, manatees, and a variety of demersal and benthic fishes and invertebrates. Some counterintuitive predictions of declines (mackerel, seabirds, and surface pelagics) resulted because these groups are somewhat dependent on benthic primary production. The overall effect of the simulated bloom-associated shading of benthic primary producers resembled a trophic cascade where the number of full cycles of biomass gains and losses was approximately equal to the number of trophic levels in the system (4.7). (C) 2003 Elsevier B.V. All rights reserved.

"We never know for sure how they died, but it does seem like a lot of the evidence points to killer whale predation," Steve Ferguson, a research scientist with Fisheries and Oceans Canada, said Thursday.

North Pacific right whales, once numbering in the tens of thousands, swam throughout the Bering Sea until they were nearly wiped out by commercial hunters. Now the Eastern North Pacific right whale population is estimated to total about 30 individuals, and its habitat is believed to be concentrated in the southeastern corner of the Bering Sea.

A heated and packed meeting of the Akranes Trade Union took place in the town last night. The municipality has strongly protested the decision of the Minister of Food to suspend this year's whaling licence.

Landmark report says invasive species are major threat to biodiversity and dealing with them requires global cooperation

Seals are typically resilient and adaptable to their environment, but a new study found that rapid warming in the past decade is causing a rampant physical decline in seals and their pups.

Researchers looked inside the stomachs of 34 spotted seals that were collected in Gambell and Shishmaref in 2012 and 2020. Of those, 33 contained microplastics.

Since 2020, members of a small group of killer whales have rammed into at least 673 vessels off the coasts of Portugal, Spain and Morocco — causing some to sink. The Spanish and Portuguese governments responded by tasking a group of experts with determining what was causing the whales to strike rudders, which are used to steer ships, and how to stop it.

Biologists were able to collect valuable data on these rare animals during a special whale survey in August.

Rising temperatures and dwindling oxygen levels are decimating marine species. But humanity can avert mass die-offs by curbing fossil fuel use and other planet-warming activities.

The Minister of Food has temporarily suspended planned whaling until August 31. A new report stated that of the 148 whales killed, 36 were shot more than once. Five were shot three times, and four whales on four separate occasions. One whale with a harpoon in its flesh was chased for five hours without success.

In recent years, polar bears in the Beaufort Sea have had to travel far outside of their traditional arctic hunting grounds which has contributed to an almost 30% decrease in their population.

Deprived of once plentiful seagrass, more than 900 have died this year. Some experts contend they were taken off the endangered species list prematurely.

Canada’s Western Hudson Bay polar bear population has fallen 27 percent in just five years, according to a government report released last week, suggesting climate change is impacting the animals.

The specific "medical" smell of whale meat may be caused by liver disease or the animals' diet. Chukchi Sea hunters began noticing the pungent, unpleasant smell in some whales about 20 years ago. Recently, the number of stinky whales has increased. Scientists with Beringia National Park analyzed the isotopic composition in 46 samples of gray whales. “Stinky” whales had significantly lower levels of heavy nitrogen. Scientists still must understand whether this is a result of liver disease or a diet based on algae. Scientists hope to study more high-quality samples of “stinky” whales.

Q fever is a febrile illness caused by infection with the bacterium Coxiella burnetii. It is most often transmitted by inhalation of the bacteria after it is shed by infected livestock. The antibody prevalence in NFS samples from 2009 and 2011 (69%) was significantly higher than in 1994 (49%). The antibody prevalence of SSL samples from 2007 to 2011 was 59%. All NFS vaginal swabs were negative for C. burnetii, despite an 80% antibody prevalence in the matched sera. The significant increase in antibody prevalence in NFS from 1994 to 2011 suggests that the pathogen may be increasingly common or that there is marked temporal variation within the vulnerable NFS population.

The number of gray whales migrating along the Pacific Coast of North America has steadily declined by nearly 40 percent from a 2016 peak, and the population produced its fewest calves on record this year, according to U.S. research released on Friday.

The number of endangered beluga whales in Alaska’s Cook Inlet increased slightly the past four years, according to a new estimate by federal biologists.

The Institute of Tribal Environmental Professionals (ITEP) Tribes and Climate Change Program is publishing a report called the Status of Tribes and Climate C...