Reeve Net Protocol
for 1997 - 1998 Broadscale Cruises
- Tows to be made at all Priority 1 stations, as far as possible.
- 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.
- 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.
- 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.
- 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.
- Label jar and complete
datasheet.
Modified March 17, 1997 - Erich Horgan
