Also see related SECM datasets:

station data
nutrients
ctd
zooplankton
fish catch data

Fish sampling

Fish sampling was accomplished with a Nordic 264 rope trawl modified to fish the surface water directly astern of the NOAA ship John N. Cobb. The trawl was 184 m long and had a mouth opening of 24 m by 30 m (depth by width). The John N. Cobb is a 29-m research vessel with a main engine of 325 horsepower and a cruising speed of 10 knots. A pair of 3-m foam-filled Lite trawl doors, each weighing 544 kg (91 kg submerged), was used to spread the trawl open. Earlier gear trials with this vessel and trawl indicated the actual fishing dimensions of the trawl to be 18 m vertical (head rope to foot rope) and 24 m horizontal (wingtip to wingtip),with a spread between the trawl doors ranging from 52 m to 60 m (Orsi et al., unpubl. cruise report 1996). Trawl mesh sizes from the jib lines aft to the cod end were 162.6 cm, 81.3 cm,40.6 cm, 20.3 cm, 12.7 cm, and 10.1 cm over the 129.6-m meshed length of the rope trawl. A 6.1-m long, 0.8-cm knotless liner was sewn into the cod end. The trawl also contained a small mesh panel of 10.2-cm mesh sewn along the jib lines on the top panel of the trawl between the head rope and the 162.6-cm mesh to reduce loss of small fish. To keep the trawl headrope at the surface, a cluster of three A-4 Polyform buoys, each encased in a knotted mesh bag, was tethered to each wingtip of the headrope, and one A-3 Polyform float was clipped onto the center of the headrope. The trawl was fished with 137 m of 1.6-cm wire main warp attached to each door and three 55-m (two 1.0-cm and one 1.3-cm) wire bridles.

Each trawl haul was fished across a station for 20 min at about 1.5 m/sec (3 knots),covering approximately 1.9 km (1.0 nautical mile). Station coordinates were targeted as the midpoint of the trawl haul; however, current, swell, and wind conditions dictated the direction in which the trawl was set. Trawling effort in the strait habitat was increased to ensure that sufficient samples of marked juvenile salmon were obtained for comparison among previous years. In particular, replicate trawls were conducted in Icy Strait when weather and time allowed, with minimal accompanying oceanographic sampling.

Station Codes:

station	locality
ABM	Auke Bay Monitor
CS A-D	Cross Sound
ED A-D	Cape Edward
FPR	False Point Retreat
IP A-D	Icy Point
IS A-D	Icy Strait
LC A-D	Lower Clarence
LFC	Lower Favorite Channel
MC A-D	Middle Clarence
TK G-I	Taku Inlet transect
UC A-D	Upper Chatham Strait

secm_fish_size_prey.csv