Baited remote underwater video stations (BRUVS) were used to examine variation in assemblages of reef fishes at scales of 100s of kilometres (between 3 marine parks in New South Wales, Australia) and kilometres (between 4 sites within each park). Temporal variation over 5 yr was also examined in 1 park (Solitary Islands). BRUVS were able to sample the relative abundance and distribution of species from a wide range of trophic groups, and were particularly effective for detecting cryptic predators. Significant variability in the fish assemblages occurred between each park consistent with the latitudinal distribution of the parks. Fish assemblages also varied significantly between sites within each park. Contrary to expectations, total species richness did not follow the expected latitudinal gradient. However, observed geographical patterns in species richness of certain families such as Labridae (greater richness in the most northern park) and Monacanthidae (greater species richness in southern parks) followed expectations. Abundant schooling species, common to all 3 parks, were important contributors to variation between sites. Temporal variation over 5 yr at 1 park was relatively minor compared to the spatial variation among the 3 parks. This suggests largescale spatial separation is more important for structuring fish assemblages than time. A network of marine parks will therefore be required to represent variation in reef fish assemblages over this latitudinal scale.

Baited remote underwater video stations (BRUVS) are increasingly being used to examine assemblages of fishes, yet critical methodological questions related to sampling limitations and bias, such as the influence of bait type, remain poorly understood. At multiple locations, we examined the hypothesis that diversity and abundance in temperate reef fish assemblages were independent of bait type. We used 3 bait types (abalone viscera, pilchards and crushed urchin) and quantified commonly used metrics for the fish assemblage, including species richness, time of first arrival and relative abundance on 3 shallow rocky reefs in southeastern Australia over 2 yr. We distinguished the following 6 feeding guilds: herbivore, zooplanktivore, alga/ invertebrate consumers, invertebrate carnivore, macroinvertebrate carnivore and generalist carnivore. The response of fishes was dependent on bait type, with urchin bait performing particularly poorly. Although we did not detect statistical differences between the performance of pilchards and abalone viscera as bait, pilchards produced more consistent outcomes. Importantly, we also observed strong spatial effects. In general, bait type had a marked effect on species richness, but little influence on relative abundance. Overall we conclude that oily bait such as pilchards, which have been widely used in most studies, yield the most consistent outcomes. Consequently, bait type and spatial variation in fish assemblages needs to be considered in sampling designs to assess the limitations of BRUVS. This article was originally published as: Wraith, J., Lynch, T., Minchinton, T. E., Broad, A. & Davis, A. R. (2013). Bait type affects fish assemblages and feeding guilds observed at baited remote underwater video stations. Marine Ecology: Progress Series, 477 189-199. 2.Abstract: Baited Remote Underwater Video Stations (BRUVS) are increasingly being used to examine assemblages of fishes, yet critical methodological questions related to sampling limitations and bias, such as the influence of bait type, remain poorly understood. At multiple locations, we examined the hypothesis that diversity and abundance in temperate reef fish assemblages were independent of bait type. We used three bait types (abalone viscera, pilchards and crushed urchin) and quantified commonly used metrics for the fish assemblage including species richness, time of first arrival and relative abundance on three shallow rocky reefs in southeastern Australia over 2 years. We distinguished the following six feeding guilds: herbivore, zooplanktivore, algae/invertebrate consumers, invertebrate carnivore, macroinvertebrate carnivore and generalist carnivore. The response of fishes was dependent on bait type with urchin bait performing particularly poorly. Although we did not detect statistical differences between the performance of pilchards and abalone viscera as bait, pilchards produced more consistent outcomes. Importantly, we also observed strong spatial effects. In general, bait type had a marked effect on species ...

To fill data gaps on movements, behaviors and habitat use, both near-and offshore, two programs were initiated to deploy satellite tags on basking sharks off the coast of California. Basking sharks are large filter-feeding sharks that are second in size only to whale sharks. Similar to many megafauna populations, available data suggest that populations are below historic levels. In the eastern North Pacific (ENP) Ocean, the limited information on basking sharks comes from nearshore habitats where they forage. From 2010 to 2011, four sharks were tagged with pop-off satellite archival tags with deployments ranging from 9 to 240 days. The tags provided both transmitted and archived data on habitat use and geographic movement patterns. Nearshore, sharks tended to move north in the summer and prefer shelf and slope habitat around San Diego, Point Conception and Monterey Bay. The two sharks with 180 and 240 days deployments left the coast in the summer and fall. Offshore their paths diverged and by January one shark had moved to near the tip of the Baja Peninsula, Mexico and the other to the waters near Hawaii, USA. Vertical habitat use was variable both within and among individuals and changed as sharks moved offshore. Nearshore, most time was spent in the mixed layer but sharks did spend hours in cold waters below the mixed layer. Offshore vertical movements depended on location. The shark that went to Hawaii had a distinct diel pattern, with days spent at ∼450-470 m and nights at ∼250-300 m and almost no time in surface waters, corresponding with the diel migration of a specific portion of the deep scattering layer. The shark that moved south along the Baja Peninsula spent progressively more time in deep water but came to the surface daily. Movement patterns and shifts in vertical habitat and use are likely linked to shifts in prey availability and oceanography. Data collected indicate the potential for large-scale movements and the need for international dialogue in any recovery efforts.

No abstract

No abstract

Mycosporine-like amino acids (MAAs) are believed to protect a variety of marine organisms against the negative effects of ultraviolet radiation (UVR). However, their role in protecting developing intertidal encapsulated embryos remains untested. In the present study, we focused on the UV protective role of natural concentrations of MAAs for two intertidal gastropod species, Bembicium nanum and Siphonaria denticulata, which lay egg masses in habitats exposed to direct sunlight. We predicted that in both species, a higher concentration of MAAs within the egg mass would increase the likelihood of embryonic survivorship in the presence of UVR. Egg masses from both species were collected along the rocky shores of southeastern New South Wales, and a portion from each was subjected to one of three separate spectral treatments: full spectrum, UV-B block, and UV block. Proportions of surviving embryos were recorded following 72 hr exposure to spectral treatment. In addition, MAAs in each egg mass were quantified. Levels of variation in MAA concentration were striking, with S. denticulata egg masses showing more intraspecific variation than those of B. nanum. Surprisingly, survivorship under all spectral treatments was extremely high for both species, irrespective of MAA concentration. Under full spectrum treatments, B. nanum survivorship and total MAA concentration were significantly and positively correlated; however, MAA accounted for just 23.6% (R = 0.486) of the variation in survivorship. In contrast, survivorship in S. denticulata was not correlated with MAA concentration under full spectrum light. We conclude that the dependence on MAAs as photoprotection may be species-specific; however, it is likely that both species possess alternative mechanisms that minimize the negative effects of UVR.

No abstract

No abstract