ABSTRACT
Identifying natal origins of marine fishes is challenging because of difficulties in conducting mark-recapture studies in marine systems. We used natural geochemical signatures in otoliths (ear bones) to determine natal sources in weakfish (Cynoscion regalis), an estuarine-spawning marine fish, in eastern North America. Spawning site fidelity ranged from 60 to 81%, comparable to estimates of natal homing in birds and anadromous fishes. These data were in contrast to genetic analyses of population structure in weakfish. Our findings highlight the need for consideration of spatial processes in fisheries models and have implications for the design of marine reserves in coastal regions.
Subject(s)
Homing Behavior , Otolithic Membrane/chemistry , Perciformes/physiology , Animals , Discriminant Analysis , Elements , Female , Isotopes , Population Dynamics , Probability , Reproduction , Seawater , United StatesABSTRACT
The Murchison and Allende chondrites contain up to 5 parts per million carbon that is enriched in carbon-13 by up to + 1100 per mil (the ratio of carbon-12 to carbon-13 is approximately 42, compared to 88 to 93 for terrestrial carbon). This "heavy" carbon is associated with neon-22 and with anomalous krypton and xenon showing the signature of the s-process (neutron capture on a slow time scale). It apparently represents interstellar grains ejected from late-type stars. A second anomalous xenon component ("CCFXe") is associated with a distinctive, light carbon (depleted in carbon-13 by 38 per mil), which, however, falls within the terrestrial range and hence may be of either local or exotic origin.
