Fixed gear susceptibility summary

Fixed gear susceptibility was generally similar across gear types, and susceptibility values are lower than those determined for trawls and dredges. Little research was available on which to base the fixed gear susceptibility values, but those papers that were used are referenced in the matrices for each gear type. Table 30 summarizes the rationale behind the structural feature susceptibility values for all the fixed gears. Recovery scores for all gear types are combined into two tables at the conclusion of the matrix results section (Table 31 – geological, Table 32 - biological). In some cases, faster recovery was expected to follow a fixed gear impact as compared to a mobile gear impact, because the gear effects are different between fixed and mobile gears. These differences are noted in the recovery summary table.

Table 30 – Fixed gears susceptibility summary for all structural features. When applicable, reasons for differences in values between gear types and/or substrates are summarized.

Feature Substrates

evaluated Score Susceptibility

Amphipods,

tube-dwelling Mud, sand 1 The percentage of amphipods impacted by fixed gear is likely very low except for direct contact with the trap or anchors. It is unlikely that much damage will occur within 1 m of the groundline/net, though some abrasion could occur.

Anemones,

actinarian Granule-pebble, cobble, boulder

1 The percentage of anemones impacted by fixed gear is likely very low except for direct contact with the trap or anchors. It is unlikely that much damage will occur within 1 m of the groundline/net, though some abrasion could occur.

Anemones, cerianthid burrowing

Mud, sand,

granule-pebble 1 The percentage of burrowing anemones impacted by fixed gear is likely very low except for direct contact with the trap or anchors. It is unlikely that much damage will occur within 1 m of the groundline/net, though some abrasion could occur.

Ascidians Sand, granule- pebble, cobble, boulder

1 The percentage of tunicates impacted by fixed gear is likely very low except for direct contact with the trap or anchors. It is unlikely that much damage will occur within 1 m of the groundline/net, though some abrasion could occur. Study 102 found evidence of tunicate detachment likely from setting and hauling back traps.

Bedforms Mud, sand 0 Currently there is no evidence that any fixed gears will alter bed forms. Gear will sit atop bedforms.

Biogenic

burrows Mud, sand 1 All three gears can collapse a burrow, especially the anchor for longline and gillnet gears. However, unlikely that the longline, gillnet or trap bottom lines will cause significant damage within 1 meter of the line/net.

Biogenic

depressions Mud, sand (mud), 0 1 (sand)

All three gears can cause damage to biogenic depressions, especially the anchor (gillnet/longlines). However, unlikely that the longline or gillnet will cause significant damage within 1 meter of the line/net.

Feature Substrates

evaluated Score Susceptibility

Boulders, scattered in sand

Boulder 0 Fixed gears do not impact this geological feature.

Brachiopods Granule- pebble, cobble, boulde

1 The percentage of brachiopds impacted by fixed gear is likely very low except for direct contact with the trap or anchors. It is unlikely that much damage will occur within 1 m of the groundline/net, though some abrasion could occur.

Bryozoans Granule- pebble, cobble, boulde

1 The percentage of erect bryozoans impacted by fixed gear is likely very low except for direct contact with the trap or anchors. It is unlikely that much damage will occur within 1 m of the groundline/net, though some abrasion could occur. Study 102 found some damage to large individuals of the ross coral, Pentapora foliacea likely caused by hauling traps.

Cobble,

pavement Cobble 0 Fixed gears do not impact this geological feature.

Cobble, piled Cobble 1 Fixed gear could dislodge piled cobbles if dragged across them. Cobble,

scattered in sand

Cobble 0 Fixed gears do not impact this geological feature.

Corals, sea

pens Mud, sand 1 The percentage of sea pens impacted by fixed gear is likely very low except for direct contact with the trap or anchors. It is unlikely that much damage will occur within 1 m of the groundline/net, though some abrasion could occur. Study 102 found that sea pens off the coast of Great Britain bent but did not break under the weight of crustacean traps. However, traps used in NE US are much heavier and likely would cause at least some damage. Granule-

pebble, pavement

Granule-

pebble 0 Fixed gears do not impact this geological feature.

Granule- pebble, scattered in sand

Granule-

pebble 0 Fixed gears do not impact this geological feature.

Hydroids Mud, sand, granule- pebble, cobble, boulder

1 The percentage of hydroids impacted by fixed gear is likely very low except for direct contact with the trap or anchors. It is unlikely that much damage will occur within 1 m of the groundline/net, though some abrasion could occur. Study 184 found lower hydroid biomass in areas that were fished heavily.

Macroalgae Granule- pebble, cobble, boulde

1 Fixed gear impacts on macroalgae are likely very low except for direct contact with the trap or anchors. It is unlikely that much damage will occur within 1 m of the groundline/net, though some abrasion could occur. Mollusks, epifaunal bivalve Mud, sand, granule- pebble, cobble, boulder

0 Long-line and gillnet gears likely do not impact this biological feature. Traps are likely to crush some bivalves that exist on hard substrates such as mussels. Polychaetes, Filograna implexa Sand, granule- pebble, cobble, boulder

1 Colonial tube worms are very fragile, and consequently are susceptible to damage via contact with anchors, gillnets, bottom lines, and traps. However, it is unlikely that more than 25% of colonial tube worm aggregations would be removed within the 1 m swath of potential impact adjacent to a gillnet, long-line, or trap bottom line.

Feature Substrates

evaluated Score Susceptibility

Polychaetes, other tube- dwelling Granule- pebble, cobble, boulder

1 Colonial tube worms are very fragile, and consequently are susceptible to damage via contact with anchors, gillnets, bottom lines, and traps. However, it is unlikely that more than 25% of colonial tube worm aggregations would be removed within the 1 m swath of potential impact adjacent to a gillnet, long-line, or trap bottom line.

Sediments, surface and subsurface

Mud, sand 0, 1

(traps) Sediment impacts expected to be limited; some compression due to traps, so score of 1 Shell deposits Mud, sand,

granule- pebble, cobble, boulder

0 Fixed gears do not impact this geological feature.

Sponges Mud, sand, granule- pebble, cobble, boulder

0 The percentage of sponges impacted by fixed gear is likely very low except for direct contact with the trap or anchors. It is unlikely that much damage will occur within 1 m of the groundline/net, though some abrasion could occur. Study 102 found evidence of sponge detachment likely from setting and hauling back traps.