Response of embryonic coral reef fishes (Pomacentridae: Amphiprion spp.) to noise

We investigated the ability of embryonic clownfishes Amphiprion ephippium and A. rubrocinctus to detect sound during incubation in benthic nests. The heart rates of embryos within eggs were monitored as the young fish were exposed to sounds in the range of 100 to 1200 Hz at levels of 80 to 150 dB (re 1 μPa at 1 m) on each day of incubation. We found that, from 3 d after fertilisation, the heart rates of the embryos significantly increased when exposed to sound. As the embryos developed, a response in heart rate was found over a broader spectrum of sound (from 400 to 700 Hz at 3 d to a maximum of 100 to 1200 kHz at 9 d after fertilisation) and sensitivity also increased, with response threshold minima at 700 Hz dropping from 139.1 dB at 3 d to 88.3 dB at 9 d after fertilisation. We discuss these findings with respect to recent work that demonstrates the importance of sound as a settlement cue in coral reef fishes. © Inter-Research 2005.Natural Environment Research Council postgraduate fellowshipBritish AssociationInstitute of Museum and Library Service of the US Department of EducationNational Institute of Mental HealthNational Organization for Hearing ResearchKentucky Water Resources Research InstituteUniversity of Kentucky Research Committee grantAustralian Institute of Marine Science gran

Ocean acidification erodes crucial auditory behaviour in a marine fish

Ocean acidification is predicted to affect marine ecosystems in many ways, including modification of fish behaviour. Previous studies have identified effects of CO2-enriched conditions on the sensory behaviour of fishes, including the loss of natural responses to odours resulting in ecologically deleterious decisions. Many fishes also rely on hearing for orientation, habitat selection, predator avoidance and communication. We used an auditory choice chamber to study the influence of CO2-enriched conditions on directional responses of juvenile clownfish (Amphiprion percula) to daytime reef noise. Rearing and test conditions were based on Intergovernmental Panel on Climate Change predictions for the twenty-first century: current-day ambient, 600, 700 and 900 matm pCO2. Juveniles from ambient CO2-conditions significantly avoided the reef noise, as expected, but this behaviour was absent in juveniles from CO2-enriched conditions. This study provides, to our knowledge, the first evidence that ocean acidification affects the auditory response of fishes, with potentially detrimental impacts on early survival

Recent advances of marine ornamental fish larviculture: broodstock reproduction, live prey and feeding regimes, and comparison between demersal and pelagic spawners

Marine ornamental fish are a key component of the multimillion‐dollar marine aquarium trade industry, a controversial industry due to current heavy reliance on wild‐collected specimens. Aquaculture of marine ornamental fish is considered as a sustainable alternative, but it is still in the early stage of development. This review focuses on the current state of marine ornamental fish aquaculture, by covering topics on reef fish reproductive biology in captivity, traditional and novel live feeds, feeding regimes and visual environment in larviculture. Where possible, major differences between demersal and pelagic spawners are compared and discussed. Overall, for many ornamental fish species, natural spawning can be achieved in a captive environment without the use of hormone induction; however, sex identification and successful pairing for reef fish species could be a challenge. With the use of both traditional (rotifers and Artemia) and novel live feeds (e.g. marine copepods and ciliates), a range of breakthroughs in larval rearing of both demersal and pelagic spawning ornamental fish species have been achieved in recent years, although larval survival varies. To further improve the larval rearing success of marine ornamental fish, this review suggests that future research should focus on optimizing the use of live feed in terms of both quality and quantity, and establishment of well‐defined species‐specific larval feeding regime, as well as providing appropriate rearing condition through improved manipulation of light conditions and the 'greenwater' techniques in larval rearing