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AMRAT
Protocols
Protocols
from Mobile Bay Assessment 2003
The Alabama-Mississippi
Rapid Assessment Team is a cooperative effort between state agencies,
universities and scientists. It
was designed to look for invasive species in a rapid 4 day snap shot of
Mobile Bay and the Mississippi Sound.
The initial effort concentrated on Alabama waters followed
by later efforts in Mississippi waters.
A large array of sampling gears was utilized to sample any area
where an invasive species had potential to become established.
Trawling
Protocol:
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.
Laboratory
Sample Workup Protocol:
- A minimum of three people were
required to efficiently process samples.
The recorder organized the appropriate AMRAT data sheets for ease
in recording the data and filled in any missing hydrologic data.
A sample was selected, placed next to the washing sink, and
opened. A number 20 sieve
was placed at the bottom of the sink and with the water running the
sample was decanted through the sieve. As the sample was washed, a small subsample was poured into
the sieve and placed on a sorting tray.
- Trawl samples were sorted directly at the
sink and trays of specimens were identified to species and recorded on
the appropriate sheet. All
individuals were counted and a total weight for the species was
recorded. Weights of
individual species was recorded prior to the entire bucket being sorted. In some samples, the number of individuals of a species may
have been in the thousands. In
this situation, a subsample of 50 measured individuals was weighed and
recorded on scratch paper. The
remaining individuals were then weighed and the total number of
individuals was calculated using the following formula:
Number of remaining individuals of species = {50 x (weight of remaining
individuals) / weight of measured 50. Total
weight for the species = weight of measured 50 + weight of remaining
individuals. Total number individuals
for species = 50 + calculated number of remaining individuals.
- In the event that a specimen could not be
identified, it was held for examination by the appropriate biologist.
Shellfish, Ballast Water, and Sediment Field Protocol Taken to the Food
and Drug Administration, Gulf Coast Seafood Laboratory for Analysis:
Protocol for handling samples from collection to delivery at the lab:
- Oysters: 12-15 live animals preferably culled
to single oysters and mussels removed
- Rangia clams: 15-20 live animals
- Place
oysters or clams from each site in 1 or 2 heavy duty plastic bags, tape
bags closed, and label site, depth, water temperature and salinity.
- Sediment:
~50 ml from top one cm of bottom surface and place in sterile or new 50
ml centrifuge tube.
- Ballast
water: 1L in sterile wide mouth Nalgene bottles that we provide.
- Place
bags of shellfish and containers of sediment and ballast water into ice
chests with bagged ice and insert bubble wrap, newspaper or card board
between samples and bags of ice to avoid direct contact. (Vibrios
survive best when slowly chilled).
- Care
should be taken not to transfer bacteria from one site to the next. Lids
on sample containers need to be tight and bags of shellfish well sealed.
Gear can be dipped in chlorinated water (1:100 in household bleach) and
rinsed with tap water or water from the collection site. Hands should be
washed in antibacterial soap and/or latex gloves worn between sampling
sites.
Rig
Scrapings taken by the Dauphin Island Sea Lab:
Protocol for rig scraping samples
by Mike Dardeau:
- A
template for scrape sampling the rig was made with legs 20cm x 20cm or
.04 m sq.
- Dove for replicate samples near the surface,
mid depth, and near the bottom.
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