DISTRIBUTION OF BLUEFISH (POMATOMUS SALTATRIX) LARVAE ALONG THE CONTINENTAL-SHELF OFF SOUTHERN BRAZIL

Data from ichthyoplankton surveys between 1980 and 1990 are used to de scribe the distribution of bluefish (Pomatomus saltatrix) larvae along the continental shelf off southern Brazil (24 degrees-35 degrees S). Only 46 larvae in 9 stations were found in 1026 oblique and horizontal tows taken with a 330 mu m-mesh Bongo net. Larvae ranged in size from 3 to 10 mm, with the larger larvae distributed close to shore. There were no significant differences in size between larvae found in the no rthern and southern regions of the shelf. However, there was evidence of a gradual northward displacement of larval abundance towards winter , About 85% of the larvae occurred in the southernmost region of the s helf (below 32 degrees S) in January and February (summer), and the re maining larvae were caught further north from March to August. This pa ttern of larval distribution could be attributed to the northwards ret reat of warmer (> 20 degrees C) and more saline (> 34) Brazilian coast al waters from the region. Results from this study suggest that bluefi sh spawn over a protracted period, following the seasonal displacement of Brazilian coastal waters along the continental shelf off southern Brazil, a pattern that is also consistent with the spawning migration proposed for bluefish in the north-western Atlantic.