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Although seabirds frequently aggregate with feeding delphinids, the benefits to seabirds of feeding with dolphins have been rarely reported. We examined how dusky dolphins (Lagenorhynchus obscurus) influenced prey accessibility for seabirds in Admiralty Bay, New Zealand. Interactions of dusky dolphins and seabirds were characterized during 335 feeding bouts of dusky dolphins (52 video-recorded underwater). Dolphins increased prey accessibility for seabirds because they swam under the bottom half of prey balls for 59% of passes that were within 2 m of the prey ball. During feeding bouts by dolphins, 51% of prey balls ascended, whereas only 13% descended. Dolphins also influenced prey mobility; only 24% of stationary feeding bouts became mobile after dolphins began feeding, and 17% subsequently became stationary again. Significantly more Australasian gannets (Morus serrator) were near mobile than stationary prey balls after feeding, but not during feeding bouts. This suggests that feeding gannets increase mobility of prey bails, but that feeding dolphins counteract this effect. Seabirds also used dusky dolphins to locate prey. Numbers of gannets, shearwaters (Puffinus), and gulls (Larus) increased during the first 2 min of dolphin feeding, even when other seabirds were not present. Gannets fed with dolphins for 40% of gannet feeding observations and shearwaters fed with dolphins for 24% of shearwater feeding observations. Key words: dusky dolphin, feeding behavior, foraging ecology, gannet, gull, Lagenorhynchus obscurus, mixed species aggregations, Morus serrator, seabird, shearwater

Research suggests that the mouth of the Mississippi River, in the northern part of the Gulf of Mexico, may be a choice locale for cetacean habitat selection. The amount of cetacean prey is higher at this site due to confluence areas and cyclones.

Resightings of photographically identified bottlenose dolphins (Tursiops truncatus) were used to calculate association indices for a population of free-ranging individuals occurring in the Galveston Bay system, Texas, and the adjacent Gulf of Mexico. Thirty-five individual dolphins with four or more sightings per year were included in the analyses to ensure likelihood of identification and comparability in 1990 and 1991. The patterns of association were weak, with few strong associations between individuals. The average association indices for 1990 and 1991 were similar; however, the magnitude of individual association indices changed drastically between the years. The low number of detectable, long-term affiliations indicates high group fluidity.

To purchase or authenticate to the full-text of this article, please visit this link: http://dx.doi.org/10.1111/j.1523-1739.2006.00471.x Byline: DING WANG (*[dagger][dagger]), XIANFENG ZHANG (*), KEXIONG WANG (*), ZHUO WEI (*), BERND WURSIG ([dagger]), GILLIAN T. BRAULIK ([double dagger]), SUSIE ELLIS (s.) Author Affiliation: (*)Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China ([dagger])Texas A&M University, 4700 Avenue U, Building 303, Galveston, TX 77551, U.S.A. ([double dagger])Downstream Research Group, 3950 S. Fletcher Avenue, Amelia Island, FL 32034, U.S.A. (s.)Conservation International, 1919 M Street, Suite 600, Washington, D.C. 20036, U.S.A. Article History: Paper submitted August 29, 2005; revised manuscript accepted February 16, 2006. Article note: ([dagger][dagger]) email wangd@ihb.ac.cn

Cetaceans THE TAXONOMIC ORDER CETACEA CONSISTS OF ABOUT 75 living species of mammals that evolved from a carnivorous stock of ungulates over 50 million years ago. They lost external hindlimbs, [...]

The article presents a study which aims at conserving habitat for the endangered Indo-Pacific humpback dolphins (Sousa chinensis) in Eastern Taiwan Strait. The study describes the habitat requirements of the dolphins and discusses the causes of the degradation of the species. It found that the dolphins are exposed to sewage and chemicals, as well as noise and disturbances. It recommends that priority habitat must be available to areas of high dolphin density or intensive dolphin use.