Over a four year period, gonad index, examination of gonad tubules, and histology were used to study the reproduction in the sea cucumber Actinopyga mauritiana. This species reproduced annually during the warmer months of the year in Solomon Islands. This annual reproductive cycle progressed through five maturity stages: recovery, growing, mature, partly-spawned and spent. The recovery stage (March–May) was marked by initiation of gametogenesis and coincided with decreasing day length. The growing stage (June–September) was characterized by development of gametes through to the mature stage (October–December). Spawning occurred October through December and coincided with increased water temperature and day length. Spent gonads (January–March) contained a few unspawned gametes or completely lacked gametes. Although A. mauritiana had annual reproduction, individuals lacking or having indeterminate gonads were present year-round. Macroscopic examination of gonad tubules after biopsy provides a practical tool for assessing maturity condition of broodstock in the field during the reproductive season.

In this study, the indirect (i.e. boats not involved in dolphin viewing activities) impacts of boat traffic on the acoustic behaviour of Pacific humpback dolphins, Sousa chinensis, were assessed in Moreton Bay, Australia. Humpback dolphin acoustic behaviour is affected by transiting boat traffic. Boats' passage did not affect the rates at which dolphins produced click trains and burst pulse vocalizations. However, dolphins significantly increased their rate of whistling immediately after a boat moved through the area. This increase occurred only when boats were less than 1·5 km from the groups. Groups including mother–calf pairs showed an increase in whistles in response to boats' passage. Groups with no calves produced significantly fewer whistles. This evidence suggests that the noise from transiting vessels affects dolphins' group cohesion. Mother–calf pairs appear to be most disturbed by transiting vessels, and exhibit an increased need to re-establish vocal contact.

The Continuous Plankton Recorder (CPR) survey has collected plankton samples from regular tracks across the world's oceans for almost 70 y. Over 299,000 spatially extensive CPR samples are archived and stored in buffered formalin. This CPR archive offers huge potential to study changes in marine communities using molecular data from a period when marine pollution, exploitation and global anthropogenic impact were much less pronounced. However, to harness the amount of data available within the CPR archive fully, it is necessary to improve techniques of larval identification, to genus and species preferably, and to obtain genetic information for historical studies of population ecology. To increase the potential of the CPR database this paper describes the first extraction, amplification by the polymerase chain reaction and utilization of a DNA sequence (mitochondrial 16S rDNA) from a CPR sample, a formalin fixed larval sandeel.

In benthic intertidal studies it is common to standardize species density, and other variables, to a square metre, regardless of the surface area sampled. Using a fully-nested sampling design, with sampling unit surface areas ranging from 0·020 to 1 m2, the present study investigated the effect of this procedure on the accuracy of the results. It is demonstrated that this standardization has a profound influence on the resultant estimates, introducing a substantial error into inter-study comparisons.

Mysids have previously been shown to consume oxygen at much lower rates when in a swarm (cohesive group in which individuals are evenly spaced but not polarized) than when in uncohesive small groups. Thus the swarm represents a strategy for conserving energy. In this study different swarm sizes of mysids were forced to perform escape responses by exposing them to jets of ammonium hydroxide, while measuring their oxygen uptake. Swarms of 200 individuals showed no significant difference in oxygen consumption with or without the ammonium treatment. In contrast, swarms of 100 showed a significant increase of around 45% oxygen uptake when exposed to ammonium. In conjunction with earlier demonstrations of increased feeding success and lower oxygen uptake when aggregated, this work clearly confirms the energetic benefits of being in a larger social group rather than a smaller one or remaining solitary.