Dataset: cod pots: catch and size
Deployment: NEC-MP2007-2

The Newfoundland design cod pots are all pyramid-shaped when fishing and are constructed in three different ways: two are approx. 2 m x 2 m x 1 m (6.5 ft x 6.5 ft x 41 in) and consist of a steel frame with netting panels; one of these designs is collapsible, saving deck space. The third construction type is 1.8 m x 1.8 m x 1 m (71 in x 71 in x 3.3 ft) and made from polyvinyl-coated wire 50 mm square mesh. All three have netting attached at the top: 30 meshes of 50 mm diamond mesh with a float whose buoyancy creates the pyramid of netting on top. Each pot has two entrances on opposite sides with 40 cm diameter circular rings. Attached to the rings are 'triggers': stainless steel 5 mm diam. rods about 50 mm apart that swing in to allow entrance, but do not swing out. The pots are designed to be static on the sea floor. Previous research (Pol and Walsh 2005) showed these three designs did not fish differently from one another, and for the purposes of this study were treated as identical.

The Norwegian design pots are collapsible two-chamber rectangular pots made of netting, with a single bridle with anchor along the short end of the pot, allowing it to float and to turn with the current, adapted from Furevik et al. (2008). They have one entrance at the opposite end as the bridle, and are made of 50 mm black poly mesh for the trap body and 50 mm white poly for the entrances (into the pot and between chambers). Three frames per pot were constructed of 2 cm diam. PVC electrical conduit, with 13 cm radius corners, glued with cement. The frame sizes were approx. 1.5 m x 1 m (4.79 ft x 3.28 ft), hung 0.7 m (2.3 ft) apart forming two chambers with a widemouth entrance in between. The bridles were anchored with >5 kg links of chain. After several months, observations of cracking in the PVC and catches of lobsters suggested that pots were not floating as expected. A pot was set in a large-scale, laboratory sea water tank, and did not float off bottom. The PVC pipes were then perforated and 11 deep-water gillnet floats were added along the upper frame to achieve proper orientation. All NO pots were subsequently modified in this manner. During the tank investigation, the top of the NO pot was measured to be 3 m off bottom; the bottom of the pot was 1.5 m off-bottom.

Locally caught clams, shelled and frozen, were used for bait during the field research. Pots were set and hauled on three or four consecutive days in each month.