Paralarval octopods of the Florida Current

Abstract

Taxonomic and ecological aspects of paralarval octopods from the Florida Current (Gulf Stream) waters off Fort Pierce, Florida are reported. Nine external morphological features were analysed in each specimen, including chromatophore patterns and meristic characters. The relative abundance of each species present in the collections made at standard stations [2–26 nautical miles (nmi) offshore at 2-nmi intervals; 1 nmi = 1.8520 km] was determined in relation to seasonal occurrence, depth of capture, distance offshore and time of day/night. The most common species in the samples was Octopus “vulgaris”, followed by Amphioctopus burryi and Macrotritopus defilippi (two morphs). Two forms could not be verified to species, but they most closely resemble Scaeurgus unicirrhus and “Octopus” joubini. The seasonal distribution of the most commonly captured species showed peak relative abundance in the summer months. Paralarval octopods were captured most frequently in the standard stations between 18 and 22 nmi (29.6–40.7 km) offshore in the mid-depth stratum of the water column. Most of the species represented in this study were captured in higher numbers at night than during the day, with the exception of A. burryi.

Keywords:

• Octopoda
• Incirrata
• paralarva
• taxonomy
• distribution

Acknowledgements

Alfredo Gutierrez gratefully acknowledges the National Museum of Natural History, Smithsonian Institution, for his appointment and grant support on the Research Training Program in 1995. We heartily acknowledge the long-term support provided by the Smithsonian Marine Station at Fort Pierce, Florida, from which an extensive cephalopod research programme was carried out over a number of years. We most especially thank our colleague, Dr Mary E. Rice, former Director of the Smithsonian Marine Station, for her strong support of our programme. The research support staff (H. Reichert, W. Lee, S. Reid, J. Kaminsky) are heartily and warmly acknowledged for their years-long support of the research of Roper and Vecchione. M.J. Sweeney was always an invaluable colleague, both at sea and ashore. We acknowledge with enthusiastic gratitude his long participation and constant good efforts on behalf of the cephalopod programme. Ingrid H. Roper, Paula Rothman and Ruth Gibbons provided invaluable technical support, of which we are most appreciative. The Humboldt Field Research Institute in Steuben, Maine and Director J. Loetze provided facilities for working on this project.