1 Meter Mocness Towing Procedure For Globec Broardscale Cruises

  1. The 1-meter MOCNESS (MOC-1) sampler is loaded with ten nets. Nets # 0-4 are 0.150-mm mesh, and nets # 5-9 are 0.335-mm mesh.
  2. MOC-1 tows are double-double oblique from surface to 10 meters off bottom. Maximum tow depth of #0 net (0.150-mm mesh) is 500 meters and for the #5 net (0.335-mm mesh) is 200 meters. A standard tow is as follows:

    NET  MESH(mm)  RATE(m/min)    STRATA(m)
     0   0.150     15m/min        Down - from surf to maximum depth
                                          or 500 meters.
     1     "         "            Up - from max tow depth to 100m.
     2     "         "            UP - from 100m to 40m.
     3     "         "            UP - from 40m to 15m.
     4     "         "            Up - from 15m to surf.
     5   0.335       "            Down - from surf to maximum depth
                                         or 500 meters.  On stations 
                                         deeper than  200 m, tow 
                                         Net #5 to 500 m and then 
                                         back to 200 m, then open #6.
     6     "       10m/min        Up - from max tow depth to 100m.
                                         (See note for net 5.)
     7     "         "            Up - from 100m to 40m.
     8     "         "            Up - from 40m to 15m.
     9     "         "            Up - from 15m to surf.  This net
                                  remains open at end of tow.   

  3. Winch rates for nets # 0-5 are 15 m/min and for nets #6-9 10m/min.
  4. During the tow, nets are tripped "on the fly" and the computer command is initiated about two meters from the next designated depth stratum to be fished. For example, when a net fishing on the up haul within the 100 to 40-meter stratum reaches 42 meters, trip the next net.
  5. At the end of the first double oblique haul (0.150-mm mesh), when the MOC-1 is at the surface, trip any remaining nets of 0.150-mm mesh (<= #4) so that net #5 (with 0.335-mm mesh)is fished on the down cast of the second double oblique cast.
  6. On completion of the second double oblique cast (nets # 5- 9), when the MOC-1 is again at the surface, Close the net fished to both minimize surface sampling and to end data acquisition. The exception is if #9 net is the last net fished, it of course cannot be closed (just mouse click "end acquistion" in tahe program) before the MOC-1 is retrieved back aboard.
  7. At stations where water depth is such that subtraction of the 10-meter off bottom safety factor results in only a few meters of depth to be sampled, the current protocol is to not fish a net for only one or two meters, but to fish a net for a 3- m or greater stratum.
Last modified: January 2, 1996
Last modified: December 21, 1995
Created: February 2, 1995