Eulerian and Lagrangian properties of biophyscial intermittency in the ocean

2000 FLORIDA AVE NW, WASHINGTON, USA, DC, 2000

Towards a Standardized Approach of Cetacean Habitat: Past Achievements and Future Directions

The understanding of what habitat means for an organism as well as the underlying factors driving patterns of habitat use is still unknown for many species. Cetacean habitat has been described using a range of methodologies and variables measured over various temporal and spatial scales that are often author-dependent. However, in order to develop an objective and sound understanding of what habitat actually means for cetaceans, a standardized approach needs to be developed. Here, after briefly reviewing the fundamental differences between terrestrial and marine habitats, we highlight the difficulty in defining a marine habitat, with a special focus on marine mammals. We subsequently provide six recommendations by which future cetacean habitat studies might be approached. This recommended approach aims to amend the way in which we think about and undertake investigations into cetacean habitat. It is believed that through this broadened approach, future cetacean habitat studies will increase our understanding of underlying driving factors of cetacean habitat, rather than just describing distribution patterns. Finally, it is stressed how the proposed approach will be more directly applicable within management frameworks and of benefit to conservation initiatives

Indo-Pacific bottlenose dolphin (Tursiops aduncus) habitat preference in a heterogeneous, urban, coastal environment

Background: Limited information is available regarding the habitat preference of the Indo-Pacific bottlenose dolphin (Tursiops aduncus) in South Australian estuarine environments. The need to overcome this paucity of information is crucial for management and conservation initiatives. This preliminary study investigates the space-time patterns of habitat preference by the Indo-Pacific bottlenose dolphin in the Port Adelaide River-Barker Inlet estuary, a South Australian, urbanised, coastal environment. More specifically, the study aim was to identify a potential preference between bare sand substrate and seagrass beds, the two habitat types present in this environment, through the resighting frequency of recognisable individual dolphins. Results: Photo-identification surveys covering the 118 km2 sanctuary area were conducted over 2 survey periods May to August 2006 and from March 2009 to February 2010. Sighting frequency of recognisable individual Indo-Pacific bottlenose dolphins established a significant preference for the bare sand habitat. More specifically, 72 and 18% of the individuals sighted at least on two occasions were observed in the bare sand and seagrass habitats respectively. This trend was consistently observed at both seasonal and annual scales, suggesting a consistency in the distinct use of these two habitats. Conclusions: It is anticipated that these results will benefit the further development of management and conservation strategies

Hydrodynamic disturbance and zooplankton swimming behaviour

EDITORIAL OFFICE, TAIPEI, TAIWAN, 11

How islands stir and fertilize the upper ocean

2000 FLORIDA AVE NW, WASHINGTON, USA, DC, 2000

The survival and reproductive performance of Daphniopsis australis (Cladocera: Daphniidae) in response to temperature changes

The thermal tolerances and reproduction of Daphniopsis australis were investigated using a single clone under laboratory conditions. Based on survivorship, measurements of thermal tolerance were conducted using acute exposure within 24, 48 and 72 hours. The upper limit of tolerance was at 28°C, but animals successfully survived until the lowest temperature (4°C) regardless of exposure times. A minimum temperature increment of 6°C above the control temperature (22°C) was detrimental to survival while the optimal temperature of this species was detected from 4 to 26°C. Variation in pattern of reproduction was observed in the range of temperature from 16 to 25°C. The reproductive parameters including age at first reproduction (AFR), clutch number, egg development time (EDT) and total offspring production were significantly affected by temperature changes. Low and high temperature significantly delayed the age for first reproduction and reduced the clutch number. However, EDT and total offspring were negatively related with an increase in temperature. An extreme thermal condition was detected at 25°C where reproductive outputs were adversely affected. Our results suggest that D. australis is a eurythermal species, but a rapid increase of temperature could threaten its survival. Reproduction of this species is favourable in the narrow range of temperature with the most optimal temperature is likely at 20°C. This study contributes to the understanding of the impact of global warming on the sustainability of zooplankton fauna in arid temperate regions