INVESTIGATING GLOBAL CHANGE AND FISH BIOLOGY WITH FISH OTOLITH RADIOCARBON

Fish otoliths, calcium carbonate gravity and auditory receptors in the membranous labyrinths of teleost fish, can provide radiocarbon data t hat are valuable to a wide range of disciplines. For example, the firs t pre- and post-bomb time series of radiocarbon levels from northern o r southern hemisphere temperate oceans was obtained by carrying out ac celerator mass spectrometry analyses on selected regions of fish otoli ths. These data can provide powerful constraints on both carbon cycle models and ocean general circulation models. Because fish otoliths can serve as a proxy of radiocarbon in seawater dissolved inorganic carbo n in all oceans and at most depths, there is considerable scope for fu rther investigations of otolith radiocarbon in relation to both oceano graphy and global change. In addition to applications relevant to glob al change, fish otoliths are also valuable sources of information on t he age, growth, and ecology of fishes, with age being among the most i mportant parameters in population modelling and fisheries management. Use of the bomb radiocarbon chronometer to validate fish age determina tion methods offers considerable advantages over traditional forms of age validation and promises to become a standard tool in fish biology and fisheries management. Radiocarbon data from otoliths can also prov ide valuable information on the ecology of fishes and has already prov ided surprising information relevant to the ecology of some deep-sea f ishes.