Intercalibration of MOCNESS and Bongo nets: Assessing relative efficiency for ichthyoplankton

The evaluation of catchability of egg and larval fish with the 0.61-m Bongo and the 1-m2 Multiple Opening and Closing Net Environmental Sensing System (MOCNESS) was conducted as part of a paired station analysis. The two samplers were deployed on 331 stations on Georges Bank during the U.S. GLOBEC program from January through June for years 1996 and 1997. Significant differences were found when combined catches of all eggs and all larvae for each sampler were compared. Overall catches of larvae from the MOCNESS were 3–5 times greater than those from the Bongo. Gear effects were modeled and revealed that the catches in 14 of the 22 dominant taxa were significantly different between sampling gear. The differences between samplers during diel intervals for the taxa were not significantly different.

► Catches from two samplers at the same sites were modeled for sampling efficiency.
► Multivariate analysis was applied to determine gear effects.
► Diel periods did not affect sampling output.
► Univariate analysis was used to detect significant levels of individual species.
► The catchability of the MOCNESS sampler was greater than that of the Bongo sampler.