Ichthyoplankton composition from PC-BELAP cruise 2, Southern Brazilian Shelf, in 1982@en

The PC-BELAP project was coordinated by Laboratório de Crustáceos Decápodos and Laboratório de Ictiologia of the Department of Oceanography of the Federal University of Rio Grande between the 31º49'S and 33ºS extending to the 60 m isobath in the years 1982 and 1983 ((Calazans, 1992; Ibagy & Sinque, 1995). Five cruises were conducted aboard NOc. Atlantico Sul, but in the first cruise (August / September 1982) no ichthyoplankton samples were analyzed. Plankton samples were collected with oblique trawls made from 1 m above the bottom to the surface with a conical 0.6 m diameter and 2.5 m long 330 ?m mesh-net coupled with a flowmeter (General Oceanics ) and a 20 kg hydrodynamic depressor. In shallow stations (i.e., with depths of 10 m or less), double oblique trawls were performed to increase the volume of filtered water (Ibagy & Sinque, 1995). The trawl velocity was estimated to be maintained between 1.5 and 2 ms-1 and vessel velocity constant at 1 ms-1 (approximately 2 kt) (Calazans, 1992). The samples were fixed and preserved in formaldehyde solution, buffered with sodium tetraborate, diluted in sea water with a final approximate concentration of 4%. The volume of filtered water was calculated and used to standardize the abundance of fish eggs and larvae per 100 m3. The identification of the eggs and larvae of fish was complete from the second cruise (November 1982) up to the 22nd station of the third cruise (January 1983). From the 23rd station of the third cruise the focus of identification was on the Clupeiformes and Sciaenidae.