1. In the field, place fish scales in envelope and fill out label 2. In the lab, label white template to correspond with envelope. 3. Position fish scales over numbers on template (numbers are right to left to appear in reverse order under microfiche). 4. Slip template between 2 acetate sheets, lining up notches. 5. […]
1. Position net(s) in flowing water, using stakes 2. After placing net in water, frequently remove organisms and debris to prevent clogging of the net mouth. 3. Specify the time of study (1 to 3 hours is recommended) and use the same time length at each station. 4. Sampling between dusk and 1 A.M. is […]
1. Lower coliwasa to desired level and pull up on rod at top to open valve, or open valve before submersing. 2. Tug slightly on rope to raise the sampler. This will set the check valve, trapping the sample inside. 3. When clear of the tank or drum, dispense the sample into an appropriate container […]
1. Place 2 slides between the rollers and adjust pressure. 2. Remove the slides, decrease the gap with dials. 3. Place the fish scale between the sides, run it through. 4. Increase or decrease pressure as needed. 6. Reuse the slide covering the scale over and over again. “In our experimental work with the roller […]
1. Store hung from a hook, upright, with all valves open. Storing when closed may damage valves. 2. Guard the sampler from blows on the cylinder ends (this may knock them out of round), a common cause of leakage. 3. Worn or age-hardened seals should be immediately replaced to prevent leakage. 4. To avoid damage […]
1. To avoid damage, use the case during transport or storage. 2. Store hung from a hook in a vertical position with all valves open. Storing closed many damage the valves. 3. Guard the sampler from blows on the cylinder ends (this may cause them to be knocked out of round), a common cause of […]
When the grab touches the bottom, inertia from a self-contained weight releases a catch and helical springs rotate the inner half cylinder by 180°. After turning, the scoop remains closed by the residual torque of the scoop spring. Because the rotation of the bucket is extremely rapid, its shear strength is far greater than the […]
Aircraft cable fits into a closing trip mechanism at the stop of the head assembly. When a messenger strikes the trip lever, a neoprene valve drops and seals the core tube under the head assembly. A suction, formed between the top valve and the core sample, creates a partial vacuum inside the core tube as […]
1. Attach a stout line to the top swivel line. 2. Tow net slowly, regulating depth by speed. 3. Tie on a tow weight for horizontal sampling
1. While setting and sampling with the surber, be careful not to disturb the substrate upstream from the sample area. This could cause organisms from outside the sample area to be caught in the net. 2. Set the surber with the net upright, water flowing into the net. The water cannot flow over the top […]