1. Scripps Institution of Oceanography University of California San Diego La Jolla California 92093 USA
2. National Marine Fisheries Service Northeast Fisheries Science Center Woods Hole Massachusetts 02543 USA
3. School of Marine Science and Ocean Engineering University of New Hampshire Durham New Hampshire 03823 USA
4. Institut Méditerranéen d'Océanologie Campus de Luminy Case 901 13288 Marseille France