Standard Gear 
Water quality equipment:
     - One Hydrolab for ph, salinity, depth, temperature and dissolved oxygen; blank hydrologic data sheet.
Trawling equipment::
     - Onboard D GPS, One lined 16' otter trawl with doors, extra 120' line (if needed – used for all Mobile Ship Channel sites and supplemental sites over 30 ft deep), sorting table/tub, index cards, pencils, permanent marker, clock/watch, ice chests with ice to hold specimens, ziploc bags to hold specimens. 

Field Sampling Methods:
     - Selection of sampling area depended on weather and sea conditions.  Once the area to be sampled was selected, a logical station order was determined according to weather conditions.
     - Upon arriving at each station, the trawl was examined for twists and other fouling problems (at stations over 30 ft in depth, extra line was added to the trawl to ensure proper sampling).  
     - With the boat at idle speed, the trawl was set out float first, followed by the net being fed out to the doors which are set so they are uncrossed and not twisted.  The bridle and tow lines were fed out with constant, light tension until all line was out, then boat speed can increase to 900-1000 rpms.  This was considered the start of trawling and the time was recorded. Trawling continued for 10 minutes.  After 10 minutes, the trawl was retrieved.  
     - Personnel observed the trawl as it was picked up and, in the event that it was found to be fouled the catch was discarded and additional trawls were made until a correct trawl was accomplished.  Once a 'good' trawl was back on board, the cod end was emptied onto the sorting table or tub and trash removed.  
     - Periodically, Division scientists requested specific species be sorted out and saved on ice in a Ziploc bag labeled with the date, site and time of trawl.  Once any special species was removed, the remainder of the sample was placed into a bucket with water and a label indicating date, site and time of set.  The trawl was examined for any gilled or stuck specimens and such organisms were removed and added to the bucket. The liner was examined for small specimens stuck to the mesh and, if found, washed into the sample bucket.  If some specimens were endangered or threatened species or too large to transport back to the lab, we obtained an identification, count and, if possible measurement, approximate weight and recorded the data on the hydrologic sheet for the appropriate site and returned the specimen alive to the water.  If the gear fished properly but no specimens were caught, we indicated that nothing was caught on the hydrologic sheet for the respective site.
     - Hydrologic data was taken at the beginning or end of a trawl.  When using a properly calibrated Hydrolab, data was taken slightly off the bottom and at the surface (6 inches below the surface) and recorded appropriately on the hydrologic data sheet.  If an unusual reading was observed, the Hydrolab was inspected for fouling and the reading retaken.  If an odd reading persisted, it was reported to the supervisor as soon as possible upon return to land.  Once readings were recorded, the Hydrolab was rinsed and stored to prevent any damage occurring from boat movement.  Once everything was securely stowed, we proceeded to the next station.
     - Once the sites were completed and the vessel returned to the office, all equipment was thoroughly cleaned and inspected for damage.  Samples were returned to the Dauphin Island Sea Lab as soon as possible for laboratory workup. 

This document does not offer much in the way of specifics of monitoring protocols.  However, it does discuss site selection, sampling stratification, sample size, etc. and encourages the collector to tailor the protocol to the specific habitat.

Generally, otter trawls are recommended.  In the Canadian Atlantic, the Western IIA otter trawl is commonly used.  Specifications of this trawl are not given.  Tows are generally for 30 min; however, this is variable.

This monitoring protocol calls for a combination of gear types, including electrofishing, hoop netting, Fyke netting and trawling. 

The standard unit of trawling effort is the 350-m-long haul.

Two-seam 4.8-m wide and 4.5-m long slingshot balloon trawls (TRL16BC, Memphis Net and Twine Co.) are used.  The body of the trawl is made of #9 nylon with 18-mm-diameter stretch mesh.  The bag of the trawl is made of #18 nylon with 18-mm-diameter stretch mesh.  The bag contains a 1.8-m liner consisting of 3-mm-diameter mesh.  Floats are spaced every 0.91 m along the top line and 4.8-mm chain is tied to the bottom line.  The trawl is operated with 37-cm-high by 75-cm-long otter boards pulled with 30-m tow lines.

Trawls are made in the downstream direction at a speed that keeps the lead line of the net in close contact with the river bottom.  Nominal trawl lengths are 350 m.  The amount of time required to cover this distance is reported as sample time in minutes.

Trawling at a site consists of a minimum of six hauls if the site is in main or side channel border areas and four hauls if the site is in a tailwater zone. 

See text for extensive description of methodology.

Trawls are made for 10-min each, at a speed of 2-3 knots.

Trawl specifications:  13.5 m headrope, 3" webbing with 1 1/2" cod-end.

This protocol was developed for nation-wide use.

Fish trawls were conducted at each site, where possible, to collect fish/shellfish for community structure and abundance estimates, collect target species for contaminant analyses, and collect specimens for histopathological examination. In some cases, it was necessary to use beach seines instead of trawls to collect fish for tissue analysis. Only trawls were used to evaluate fish community structure because consistency between beach seines was impossible to maintain.

Trawls were conducted by using a 16-ft otter trawl with 1.5-inch mesh in the body and wings and 1.25-inch mesh in the cod end.  Community structure data (i.e, the fish data on richness and abundance andindividual lengths) were based on a trawl(s) of 10 minute duration.  In open water, the trawl was conducted in a straight line with the site location near center.  Timing of the trawl began after the length of towline had been payed out and the net began its plow. The speed over bottom was approximately 2 knots.  When possible, trawling was conducted for the entire 10-minute period, after which the ship's transmission was placed in neutral and the trawl net retrieved and brought aboard.  In constrained areas where 10-minute trawls were not possible, two 5-minute trawls were conducted. Contents of the bag were emptied into an appropriately sized trough or livebox to await sorting, identifying, measuring, and sub-sampling.  Trawling was the last field activity performed because of possible disturbance to conditions at the site. Every effort was made to return any rare or endangered species back to the water before they suffered undue stress.

In Oregon and Washington, fish for tissue and histopathological analysis were collected with a 120-foot long beach seine where waters were too shallow to use the otter trawl.  The seine had 1-inch m

For the Southeast and Gulf, which generally have shallower estuaries we use a 16 ft otter trawl, other than using the smaller trawl, other conditions are basically the same as West coast and Northeast.  Any modifications to the net or the trawling procedure must be discussed with our QA group and approved, so that data collection methods are consistent and comparable.  Fish trawls are not intended to constitute a population or stock assessment, but rather to collect specimens for tissue analyses, provide gross pathology determinations, and provide a very gross view of diversity/abundance among fish in a particular resource.

 and Gulf.

An otter trawl was used (400 mesh Eastern bottom trawl).  A schematic of the trawl is in the report.  The trawl had 4-inch mesh in the body and 3 1/2 inch mesh at the cod end.  The mouth of the net varied in width (depending on tow speed and depth [aka "scope"]) from 8.7 to 12.7 m.

Tows were for 10 min at 1.5 to 2.5 knots.