Let's Talk Halibut Prohibited Species Bycatch

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Wiglaf has made some strong statements in the past couple of years regarding trawl bycatch.  For a New Year Review, let's consider some Take Away Messages from 'official sources.'  These are the same sources that accuse Tholepin of  being unreliable.  Go figure.

Take Away Message: Too much halibut bycatch.

IPHC:  "The existing GOA Prohibited Species Cap (PSC) limits have been in place for trawl fisheries since 1986 and for fixed gear fisheries since 1996.  The Commission staff believes that these limits were based on inadequate data, that monitoring of both historical and current bycatch mortality is similarly inadequate, and that the PSC limit for trawl fisheries should be reduced as a precautionary measure until the improved observer procedures are implemented, at which time the estimated bycatch mortaality levels can be re-evaluated to the context of halibut stock dynamics." IPHC

Take Away Message: Statistics regarding bycatch are NOT reliable.

NMFS:  "The current federal groundfish observer program in Alaska is structured by vessel size. As such, groundfish vessels less than 60’ are not required to carry observers; vessels 60’ – 125’ length overall(LOA) are required to carry and pay for their own observers 30 percent of their fishing days, regardless of gear type or target fishery; vessels greater than 125’ LOA are required to carry observers 100 percent of the time. Vessels in the 30 percent coverage category select when to carry observers and are constrained in this self-selection by regulatory requirements for quarterly coverage levels. The two size categories with less than 100 percent observer coverage comprise the majority of vessels fishing in the GOA and out of ports other than Dutch Harbor and Akutan in the BSAI.

“Observers estimate total catch for a portion of hauls or sets, and sample hauls or sets for species composition, including PSC. These data are extrapolated in the Alaska Region Catch Accounting System (CAS) to make estimates of total PSC halibut catch on both observed and unobserved vessels. Observer data are assumed to be representative of the activity of all vessels and are used to estimate total halibut PSC. The ratio estimator is derived from a set of covariates that match both observer and groundfish landing/production information. A detailed description of this process is presented in Cahalan et al. (2010).

Regulations governing observer deployment (i.e., observer coverage requirements) introduces the potential of bias in observer data by using a non-random deployment model which may facilitate nonrepresentative fishing. Given the use of observer data in CAS, and the subsequent use of CAS estimation in stock assessments and quota management, this issue can undermine the data used to manage halibut PSC (among other species) in the North Pacific groundfish fisheries. In response to these issues, the Council took action at its October 2010 meeting to recommend that NMFS restructure the observer program to address multiple issues with the current program, including bias (NPFM 2010). The recommended restructuring preferred alternative provides NMFS with flexibility to place observers onboard vessel using accepted statistical practices so that coverage gaps and vessel-trip selection bias is addressed.” NMFS.

Take Away Message: We are hurting the halibut biomass, its reproductive potential, and the future of all halibut fisheries.

 NMFS:  The impacts of reducing halibut PSC limits for groundfish target fisheries does not simply reallocate that reduced halibut mortality amounts to directed fishery halibut users. While halibut PSC limits are often closely approached in the GOA groundfish fisheries, these removals are known imprecisely. While all halibut mortality sources are taken into account when commercial IFQ catch limits (and combined catch limits under the proposed Halibut Catch Sharing Plan (CSP)) are set, the negative impacts of these removals on lost spawning biomass and lost yield are not prevented. Incidental catches of halibut result ina decline in the halibut standing stock biomass, reduced reproductive potential of the halibut stock, and reduced short- and long-term halibut yields to the directed hook-and-line fisheries and the guided sport sector in Area 2C and 3A under the proposed CSP.

A reciprocal function of the Take Away Message is the Red Face Test:

1.       NMFS:  “The GOA groundfish fishery has an adverse impact on Pacific halibut through direct mortality due to prohibited species catch. Under the status quo, Pacific halibut are a prohibited species and it is incumbent upon fishermen, under the regulations, to avoid catching them. The Groundfish Programmatic EIS considered impacts of the fisheries on the halibut population, reproductive success, and habitat, and concluded that it is unlikely that groundfish fishing has indirect impacts on these aspects of Pacific halibut sustainability.” http://alaskafisheries.noaa.gov/npfmc/PDFdocuments/halibut/HalibutPSCLimit911_exsum.pdf

 Wiglaf:  Red Face Test Fail!  This simply does not fit with what the IPHC has stated in the first paragraph.  Trawling has severe effects upon the viability of halibut as a fishery resource.  Since the observer system produces unreliable data regarding bycatch in general, how does NMFS get away with determining that: “it is unlikely that groundfish fishing has indirect impacts on these aspects of Pacific halibut sustainability.” 

2.       NMFS:  The groundfish fisheries also incidentally catches halibut prey species, including euphausiids, herring, sand lance, capelin, smelt, pollock, sablefish, cod, rockfishes, octopus, crabs, and clams, however the catches of these prey species are very small relative to the overall populations of these species. Thus, groundfish fishing activities are considered to have minimal and temporary effects on prey availability for halibut.” http://alaskafisheries.noaa.gov/npfmc/PDFdocuments/halibut/HalibutPSCLimit911_exsum.pdf

Wiglaf:  Red Face Test Fail!  Welcome to the zone of great unknowns.  <If >;” the proportional catches of prey species are small” … we can’t know that based upon the admission that:  “Given the use of observer data in CAS, and the subsequent use of CAS estimation in stock assessments and quota management, this issue can undermine the data used to manage halibut PSC (among other species) in the North Pacific groundfish fisheries.”  Also, it is likely that evidence of catches of many very small and fragile prey species may be missing from recovered trawls because they break up and are washed out of the drags.  That these prey species are important is obvious.  Plenty of trawl crew have reportedly seen large numbers of small prey species washing out of cod ends upon recovery.  To state that trawls don’t have an important effect on prey species is at best wishful thinking and at worst a lie.  If a prey species dies in the trawl but is washed away with no one to see it, did it exist?

Keep Yer Flippers Wet