Marine and Freshwater Research
Number 11 2014
Whether spatial variation occurs in chondrichthyan species life-history traits is important to fisheries management and assessments. While providing a greater understanding of the reproductive biology of U. paucimaculatus from SE Australia, the present study also demonstrates U. paucimaculatus have phenotypically adapted their reproduction to surrounding environments, with regional differences within SE, and between SE and SW Australian populations. The present study provides further evidence that chondrichthyan life-history traits can vary within small geographical areas.
Shark resource-use strategies affect how they will respond to changes within their environment and therefore may be important in management. This study used acoustic telemetry to examine the habitat use of Rhizoprionodon taylori and found individuals consistently selected for seagrass, potentially for feeding. These results will contribute to a better understanding of how small-bodied sharks use nearshore areas.
Marine biologists have long recognised that ocean currents play a key role dispersing species that drift in the plankton, but the influence of coastline geometry on marine biology is less understood. This study analyses the distributions of two common intertidal snail species associated with distinct Australian coastal currents, and shows a relationship between coastal orientation and species relative abundance where these currents meet. The work suggests that oceanography and topography combine to influence marine species distributions.
Transgenerational isotopic marking has been recognised as an efficient tool for mass marking of high numbers of fish larvae by injecting female spawners with enriched isotope solutions. In this study, 86Sr/84Sr double spikes in combination with isotope pattern deconvolution for the identification of the originally injected 86Sr/84Sr molar fraction ratios in otolith cores were successfully applied for individual-specific marking of the offspring of a typical freshwater fish species, the common carp (Cyprinus carpio). Enriched stable Sr isotope double spikes represent an important alternative to enriched stable Ba isotopes for transgenerational marking, especially in freshwater systems.
The effect of hydrodynamic features on salinity in the Senegal River Estuary (SRE) was studied with a combination of three-dimensional modelling and field measurements. Indeed, the SRE is of strategic importance for large populations, but human action has caused major changes in salinity and ecological functioning. This study provides a tool for managing the water in such areas.
Wobbegong and angel sharks can detect the electric fields of animals passing over their heads while they sit motionless on the sea floor waiting to ambush suitable prey. Although these two species are very distantly related, they have both evolved this similar mechanism for identifying prey. This study, therefore, emphasises the important role of electroreception in the feeding behaviour of sharks.
In this paper we investigate changes in urban stream pH, salinity and minerals across different levels of urban development. Results of this study suggest that concrete, a widespread urban material, is a major source of salinity and mineral contamination of urban streams as catchments become increasingly urbanised. Such contamination requires further investigation as it probably contributes to the ecological stress evident in urban streams.
Parasites dominate coral reef animal diversity, yet their contribution to reef dynamics is poorly studied. We quantified infection prevalence of a conspicuous ectoparasite (Anilocra haemuli) on French grunt (Haemulon flavolineatum) hosts, and found it to be extremely variable (0–66%) and highest for small groups and solitary fish. We provide essential baseline data for future studies on the ecology of this parasite.
Recent studies suggesting perceptions of the identities and distributions of Indo-West Pacific species of the deepwater fish genus Chlorophthalmus are incorrect provided incentive for a study using DNA and morphological evidence. Results supported the recognition of 14 rather than 9 species as currently recognised. The outcome reinforces growing perceptions that deepwater fishes are more diverse and narrowly distributed than long accepted.
Information on the reproduction of the pelagic stingray, Pteroplatytrygon violacea, in the wild is particularly limited. We analysed data for 188 females and 292 males and their reproductive biology was studied. Size at first sexual maturity was estimated at ~48.0 cm DW (disk width) for females and ~41.0 cm DW for males. The information generated by this study will contribute to a better assessment of the stocks of pelagic stingrays in the Atlantic Ocean.