Bristol Bay Red King Crab
1997 StudyPot Catchability
A total of 117 pots were fished during the pot catchability experiment. Fifty-eight pots containing two tunnels were alternately deployed with fifty-nine pots containing one tunnel. A total of 2,827 legal and 3,369 sublegal males and 341 females were captured. Overall, pots with two tunnel openings averaged nearly 30 legal-sized red king crab, and single-tunneled pots averaged approximately 19 red king crab per pot; as expected catch rates of the 2 tunneled pots were significantly higher than those of pots containing a single tunnel.Soak Time Study
A randomized block design employed for the pot soak study consisted of deploying 4 blocks of 36 pots. The data results grouped by soak category, showed the mean catch of crabs per pot increasing as pot soak time increased and ratio of sublegal to legal crab decreasing simultaneously.
|Soak Category||Legal||Sublegal||Ratio Sublegal to Legal|
|12 hr soak||8.7||19.2||2.2:1|
|36 hr (projected)||13.7||22.0||1.6:1|
|48 hr (projected)||16.4||23.6||1.4:1|
Bristol Bay Test Fish Project Data Summary Report, 1997. (Moore, H. 1998)
A study of red king and Tanner crab catches using an experimental king crab pot design and commercial king and Tanner crab pots outfitted with egress devices (escape rings) was conducted in the Bristol Bay waters east of 168 degrees longitude. A comparison between the experimental king crab pot design and the standard king crab pot design and a comparison between standard king and Tanner crab pots with and without egress devices (escape rings) was made based on the catch abundance and size distribution of male and female red king crabs and legal-sized Tanner crabs.
The primary objectives of this research were to determine how well bycatch is reduced in experimental pots and pots with egress devices and how well legal king and Tanner crabs are maintained in these same pots.
The pot types used in the study were assigned numbers and defined as follows:
- Pot Type 1 (standard king crab pot) - Commercial pots with two 20.3-cm (8-in) tunnels and 12.7-cm (5-in) stretch mesh. These pots were used for cost recovery fishing and alternately deployed in blocks with experimental pots and in blocks with pots containing four 15.2-cm (6-in) escape rings.
- Pot Type 2 (experimental king crab pot) - The patented king crab pot design described in Zhou (1996). These pots were randomly deployed during cost recovery fishing and alternately deployed in blocks with standard king crab pots.
- Pot Type 3 (escape ring king crab pot) - Standard king crab pots with opilio curtains covering the enlarged web. These pots were outfitted with four 15.2-cm (6-in) escape rings sewn into two of the vertical panels within 45.7-cm (18-in) of the pot base. These pots were alternately deployed in blocks with standard king crab pots.
- Pot Type 4 (Standard Tanner crab pot) - Commercial Tanner pots with two 7.6-cm (3-in) Dorian ® tunnels and opilio curtains covering the enlarged web panel. These pots were alternately deployed in blocks with pots containing four 12.7-cm (5-in) escape rings.
- Pot Type 5 (Escape ring Tanner crab pot) - Standard Tanner crab pots outfitted with four 12.7-cm (5-in) escape rings sewn into two of the vertical panels and within 45.7-cm (18-in) of the pot base. These pots were alternately deployed in blocks with standard Tanner crab pots. Preliminary results summarizing catch of red king and Tanner crabs by paired pot types are shown in the table below.
Summary of Red King and Tanner crabs from 25 stations in the 1996 Bristol Bay red king crab test fishery.
|PAIRED POT TYPES||PAIRED POT TYPES||PAIRED POT TYPES|
|Pot Type 1||Pot Type 2||Pot Type 1||Pot Type 3||Pot Type 4||Pot Type 5|
|All Red King Crab||2853||29.7||2562||26.7||5198||36.0||4976||35.0||5135||32.1||3983||24.9|
|All Bairdi Tanners||78||0.8||108||1.1||152||1.1||332||2.3||865||5.4||851||5.3|
A summary of biological data collected during the 1996 Bristol Bay red king crab fishery. (Byersdorfer, S. 1996.)