IPHC Bycatch Workshop Background Material

Presentations (Preliminary)

Bycatch Workshop Outline (pdf) - Bruce M. Leaman

Bycatch History and Status (pdf) - Gregg H. Williams

Accounting for Bycatch Impacts (pdf) - Steven R. Hare, Juan L. Valero, Ray A. Webster, Gregg H. Williams, Bruce M. Leaman, IPHC staff

Effect of Migration on Impacts (pdf) - Juan L. Valero, Steven R. Hare

Bycatch Policy Matters (pdf) - revised 11/23/09 - Bruce M. Leaman, Gregg H. Williams

Documents

IPHC Technical Report No. 25 - Report of the Halibut Bycatch Work Group. S. Salveson, B.M. Leaman, L. L-L. Low, and J.C. Rice 29 p. (1992).

Scientific Report No. 78 - Pacific halibut bycatch in the groundfish fisheries: Effects on and management implications for the halibut fishery. Patrick J. Sullivan, Robert J. Trumble, and Sara A. Adlerstein. 28 p. (1994).

Accounting for pre-recruit halibut bycatch mortality through harvest rate adjustment. William G. Clark, Ana M. Parma and Patrick J. Sullivan. 1996 RARA, pp 131-139)

Accounting for bycatch in management of the Pacific halibut fishery.William G. Clark and Steven R. Hare. 1998. North American Journal of Fisheries Management 18: 809-821.

Discussion paper on "regularizing" of bycatch, sport, and subsistence catch. Steven R. Hare and William G. Clark. 2006 RARA, pp. 191-196.

Incidental catch and mortality 1962-2008. Gregg Williams.

Halibut Discard Mortality Rate recommendations. Gregg Williams

Incidental catch and mortality of Pacific halibut, 1962-1989. Williams, G. H., C. C. Schmitt, S. H. Hoag, And J. D. Berger. 1989. Int. Pac. Halibut Comm., Tech. Rep. No. 23. 94 p.

Data Files

The links below are for an excel spreadsheet and a pdf file for all forms of halibut removals.

There are seven categories: Commercial catch (which includes catch aboard our survey), Sport catch, Bycatch (legal-sized), Personal use and subsistence, Commercial wastage (legal-sized), Bycatch (sublegal-sized), and Commercial wastage (sublegal-sized):

Total Removals (Excel 2003 spreadsheet)

Total Removals (Adobe pdf)

The first five categories all get "charged" to the CEY in the regulatory area where taken, the other two do NOT (they are incorporated into determination of the harvest rate)

IPHC halibut bycatch historic estimates. Gregg Williams

BC trawl bycatch annual estimates. Gregg Williams

I have assembled sublegal bycatch mortality values for all areas since 1996, grouped into 5 cm length categories. The categories begin at 7 cm (representing 1-9 cm), then 12cm (for 10-14 cm) and so on up to 77 cm (for 75 to 81 cm). The spreadsheet contains both numbers of bycaught halibut as well as estimated weight in each length category. The linked pdfs show the numbers of mortalities for each area, grouped into one plot, for each of the past 5 years. These values represent ALL sublegal bycatch mortality, not just trawl bycatch. I could, with more work, produce plots for just trawl but I think what is important is all sublegal bycatch mortality, including that from longline bycatch fisheries. In most of the areas, the bycatch is predominantly due to either trawl or longline so you get the general idea.

Sublegal bycatch by length

Plot of 2004 sublegal bycatch 

Plot of 2005 sublegal bycatch 

Plot of 2006 sublegal bycatch 

Plot of 2007 sublegal bycatch 

Plot of 2008 sublegal bycatch 

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