Matis, PA, Donelson, JM, Bush, S, Fox, RJ & Booth, DJ 2018, 'Temperature influences habitat preference of coral reef fishes: Will generalists become more specialised in a warming ocean?', Global change biology, vol. 24, no. 7, pp. 3158-3169.View/Download from: UTS OPUS or Publisher's site
Climate change is expected to pose a significant risk to species that exhibit strong behavioural preferences for specific habitat types, with generalist species assumed to be less vulnerable. In this study, we conducted habitat choice experiments to determine how water temperature influences habitat preference for three common species of coral reef damselfish (Pomacentridae) that differ in their levels of habitat specialisation. The lemon damselfish Pomacentrus moluccensis, a habitat specialist, consistently selected complex coral habitat across all temperature treatments (selected based on local average seasonal temperatures naturally experienced in situ: ambient winter 22°C; ambient summer 28°C; and elevated 31°C). Unexpectedly, the neon damselfish Pomacentrus coelestis and scissortail sergeant Abudefduf sexfasciatus, both of which have more generalist habitat associations, developed strong habitat preferences (for complex coral and boulder habitat, respectively) at the elevated temperature treatment (31°C) compared to no single preferred habitat at 22°C or 28°C. The observed shifts in habitat preference with temperature suggest that we may be currently underestimating the vulnerability of some habitat generalists to climate change and highlight that the ongoing loss of complex live coral through coral bleaching could further exacerbate resource overlap and species competition in ways not currently considered in climate change models.
Matis, PA, Figueira, WF, Suthers, IM, Humphries, J, Miskiewicz, AG, Coleman, RA, Kelaher, BP & Taylor, MD 2014, 'Cyclonic entrainment? The icthyoplankton attributes of three major water mass types generated by the separation of the East Australian Current', ICES Journal of Marine Science, vol. Online.View/Download from: Publisher's site
The relationship between larval fish assemblages and coastal oceanography is the basis for much of our understanding of connectivity and productivity of fish populations. Larval fish assemblages were sampled from the upper mixed layer (<50 m depth) at three prominent circulation features [separation of the East Australian Current (EAC), anticyclonic eddy, and cyclonic eddy] off the southeast Australian coast across three bathymetric zones (shelf, slope and ocean) for each feature. The separation of the EAC from the coast at ~32°S was characterized by warmer, less saline water compared with the cyclonic and anticyclonic eddies further to the south (~34 and ~35°S, respectively), which were both characterized by cooler Tasman Sea water and greater fluorescence. The anticyclonic eddy had separated from the EAC three months prior to sampling, which facilitated the movement of a cyclonic eddy from the Tasman Sea westwards to the shelf at ~34°S. The larval assemblage in the EAC had high numbers of fish of the families Labridae and Stomiidae. The cyclonic eddy was characterized by larval clupeids, carangids, scombrids and bothids, indicating recent entrainment of shelf waters and proximity to major spawning regions. In contrast, the anticyclonic eddy had fewer larval fish, with little evidence for entrainment of shelf assemblages into the near-surface waters. Myctophids were found in high abundance across all oceanographic features and bathymetric zones. The evidence of selective entrainment of coastal larval fish into the near-surface waters of a cyclonic eddy compared with a similar anticyclonic eddy indicates a potential offshore nursery ground.