Reeve Net Protocol for 1997 - 1998 Broadscale Cruises

  1. Tows to be made at all Priority 1 stations, as far as possible.

  2. At Priority 1 stations where a 10 m MOCNESS trawl is not made because of weather conditions, we would especially like the Reeve net tow to be made, since it would then be the only sample for large jellies.

  3. Tows are vertical, made from the depth of the deepest MOC-10 net, (usually 0- 15 m off the bottom), and to a maximum depth of no more than 200m. Ideally, the net bridle is fastened to the end of the wire, so that it hangs below it. If the net cannot be attached to the end of the wire, it can be fastened with a book clamp near the end. Next, attach the cod-end to the net ring using the snap-shackle (this will help to get the whole net over using the hydro-winch). The large, solid cod-end needs to be filled with water before lowering. It is not necessary to use a flowmeter with these tows; we will calculate volume filtered from mouth diameter and depth.

  4. The net should be hauled up at about 5 m/min, and carefully retrieved over the side, keeping the cod-end upright. Partially unzip the fabric surrounding the cod-end and inspect the catch for larger gelatinous predators.

  5. Since much of the cast may be fragile (large ctenophores, etc.), it needs to be examined immediately, before preservation. At a minimum, we would like a count of the large jellies, particularly lobate ctenophores (i.e. Bolinopsis, Mnemiopsis, and if possible, measurement (oral / aboral length ) of a representative subsample by gently placing the animals in shallow observation / petri dishes and measuring from below the dish with a ruler. The entire catch should then be sieved (330 micron stainless) and preserved in a liter jar in 5% buffered formalin.

  6. Label jar and complete datasheet.

    Modified March 17, 1997 - Erich Horgan