The vertical egg tow, referred to as CV in the CalCOFI database, was used to sample anchovy eggs from 1980 through 1985. The net frame consisted of either a single or pair of anodized aluminum circles, 0.25 m in diameter, connected directly to the towing cable, to which elongate cylindrical-conical shaped nets were attached. The nets were 1.5 m in length, a 0.8 m cylindrical portion joined to 0.6 m conical portion tapering to a 0.1 m cod end. From 1980 through 1982 the net was made of 0.333 mm square mesh nylon; from 1983 through 1985 the net was made of 0.150 mm square mesh nylon. The ratio of mesh aperture area to mouth area was about 8:1 for both nets.
Egg samples were obtained by vertically retrieving the net. A 45 kg weight is attached to the end of the towing cable, a few meters below the sampler. With the survey ship holding a stationary position, 70 m of towing cable was paid out, the net was held at depth for 10 seconds and then retrieved vertically at a rate of 70 m/min. The angle of stray from the vertical was not allowed to exceed 15 degrees.
The replacement for the CALVET is the PAIROVET which is the referred in the CalCOFI database as PV.