Questionnaire Report for rougheye rockfish

(MERA version 4.1.6)


1 About this document

This is a prototype of an automatic report that documents how the user specified the operating model and their various justifications.

2 Introduction

  1. Describe the history and current status of the fishery, including fleets, sectors, vessel types and practices/gear by vessel type, landing ports, economics/markets, whether targeted/bycatch, other stocks caught in the fishery.

This fishery comprises two species, Rougheye Rockfish (Sebastes aleutianus) and Blackspotted Rockfish (Sebastes melanostictus). it is not possible to separate these species in the fishing operations. The only known method to distinguish the two species accurately is through DNA analysis. The recently discovered existence of two species within what was formerly known as Rougheye Rockfish, and the resultant lack of biological knowledge of the Rougheye/Blackspotted Rockfish complex could constitute a threat in itself, due to the increased risk of loss of unrecognized biological diversity (Fisheries and Oceans Canada. 2012). The Rougheye/Blackspotted Rockfish complex and Longspine Thornyhead are harvested by the commercial groundfish fishery in British Columbia. This fishery is managed by Total Allowable Catches (TACs), Individual Vessel Quotas (IVQs), as well as 100% at-sea and dockside monitoring programs. The Rougheye/Blackspotted Rockfish complex and Longspine Thornyhead are listed under the Species at Risk Act as ‘special concern’ meaning that they are considered wildlife species that could become threatened or endangered because of a combination of biological characteristics and identified threats. COSEWIC Status: Special Concern.

  1. Describe the stock’s ecosystem functions, dependencies, and habitat types. The highest densities of the Rougheye/Blackspotted Rockfish complex occurs on the sea floor with soft substrates, in areas with frequent boulders and on slopes greater than 20°. The association with soft substrate may be attritutable to preferred prey items like pandalid shrimps (stomach content analyses, Yang and Nelson 2000). The Rougheye/Blackspotted Rockfish complex co-occurs with numerous commercially harvested species, including Pacific ocean perch (Sebastes alutus) and Arrowtooth Flounder (Atheresthes stomias) in the groundfish trawl fishery, and Redbanded Rockfish (S. babcocki) and Shortraker Rockfish (S. borealis) in the groundfish hook and line fisheries (Figure 5). Other than competition for food resources with these species, there is no current information on interactions that might limit the survival of the Rougheye/Blackspotted Rockfish complex. (Fisheries and Oceans Canada. 2012, p16). Predators likely include Pacific Halibut (Hippoglossus stenolepis), Pacific Cod (Gadus macrocephalus), and Sablefish (Amoplopoma fimbria) (Shotwell et al. 2009).

  2. Provide all relevant reference materials, such as assessments, research, and other analysis.

In Canadian waters abundance information is derived from surveys and from the commercial fishery that has maintained a relatively constant reported catch of between 1000 and 2000 tonnes annually over the last two decades. Abundance indices and biomass estimates are uncertain, compromised by short time series and survey techniques not always appropriate for the species. No strong abundance trends are observed in the available indices. There is evidence of truncation of the age distribution over the last decade, suggesting that mortality from all sources may have doubled (4.5% y -1 to 9.1%y -1 ). Long-lived, low-fecundity Sebastes species are particularly susceptible to population collapse, and recovery may be compromised when the age- and size-distribution is truncated (i.e., when the number of spawners declines) through fishing (Fisheries and Oceans Canada. 2012, p8). The complex co-occurs with numerous commercially harvested species, including Arrowtooth Flounder (Atheresthes stomias), Pacific Ocean Perch (Sebastes alutus), Dover Sole (Microstomus pacificus), Petrale Sole (Eopsetta jordani), Shortspine Thornyhead (Sebastolobus alascanus), and Sablefish (Anoplopoma fimbria) (Fisheries and Oceans Canada. 2012, p15). Given the benthic nature of the complex, it is targeted by the commercial groundfish trawl and hook and line fleets. The commercial harvest for these species (Tables 2 and 3) are managed by DFO. The DFO establishes a commercial Total Allowable Catch (TAC) for the Rougheye/Blackspotted Rockfish Complex and Longspine Thornyhead, which sets the maximum amount of harvest permitted to be taken, as well as the area they may be taken from, in a given fishing season. These TACs are changed over time as new peer-reviewed science information becomes available. The coastwide TAC is currently 1,140 tonnes for the Rougheye/Blackspotted Rockfish complex and 425 tonnes for Longspine Thornyhead. In addition, these fisheries are managed using individual transferable quotas (ITQs), which allows the trading of quota within and between the various commercial groundfish fishing sectors. Furthermore, the commercial fishing sector is subject to a comprehensive 100% at-sea and dockside monitoring program (Fisheries and Oceans Canada. 2012, p23). Considerable additional scientific work will be required to describe the relative abundance of the two species in Canadian waters, their distribution, and the impacts of fisheries (and potentially other threats) on each. nCurrently, DFO has little information on Rougheye Rockfish and Blackspotted Rockfish (S. melanostictus) in Canadian Pacific waters. Based on the diagnostics reported in the literature, DFO Science surveys initially tried to distinguish these species based on the presence and/or absence of discrete spots on the dorsal fin, but abandoned this practice due to high pattern variability. Difficulty in distinguishing Rougheye and Blackspotted Rockfish presents a challenge to the management of both species. In the absence of sufficient biological information on either species, the two can only be managed as a species complex, until sufficient research identifies a method to manage them separately between the two species. The main threat to the Rougheye/Blackspotted Rockfish complex and Longspine Thornyhead is population decline as a result of direct and indirect biological resource use. Although there is a lack of knowledge on the relative abundance and distribution of Rougheye and Blackspotted Rockfish, management actions that may reduce the risk of population-level threats should be considered. Stock status is currently based on relative abundance indices from DFO Science surveys or commercial CPUE to monitor trends in populations (see Section 2.3.3). The current management regime (outlined in Section 1.8) regulates the commercial Rougheye/Blackspotted Rockfish complex and Longspine Thornyhead fisheries through the use of ITQs, trip limits and a comprehensive catch monitoring program. Management tools that are available to DFO fishery managers include the use of area and time closures and adjusting species’ TAC limits. In addition, fishery management objectives are reviewed every season and included in annual IFMPs, which are used to guide the management of the fishery (see Sections 2.3.3 and 4). Since the COSEWIC Stock Status Report for the Rougheye/Blackspotted Rockfish complex was published in 2007, DFO Science has added new index points to the various DFO Science research survey series. DFO Science will continue to gather Rougheye Rockfish and Blackspotted Rockfish data from the various DFO Science surveys to monitor and assess population trends and abundance. In addition, when sufficient genetic samples of the rockfish complex are gathered, DFO Science should be able to determine proportions of Rougheye Rockfish and Blackspotted Rockfish in Canadian Pacific waters. These ratios might also be useful in disaggregating historic catches where only Rougheye Rockfish were reported. For the Rougheye/Blackspotted Rockfish complex, ageing otoliths via break-and-burn results in a high degree of imprecision (± 5 y, Shayne MacLellan, DFO, pers. comm., supervisor of the PBS fish ageing laboratory, 2010). Ageing error won’t disable an age structured model, but it probably increases the uncertainty of the results.

Abundance indices can be constructed from numerous data sources – Hecate Strait (HS) assemblage survey, Queen Charlotte Sound (QCS) synoptic survey, QCS shrimp survey, west coast of Vancouver Island (WCVI) shrimp survey, and the observed commercial trawl fishery. Most of these are unsuitable as abundance indices due to high index CVs for this species. The most appropriate surveys for abundance indices in future will be the synoptic groundfish surveys started in 2003 (Stanley et al. 2004). Currently these are running in QCS and WCVI. As the density of rougheye rockfish is highest off the west coast of the Queen Charlotte Islands (WQCI), a similar synoptic survey is needed in this region (Haigh et al., 2005, p1). While survey data are generally considered the most reliable method to use for monitoring demersal marine species, the large error bars in all these surveys indicate that estimated trends are highly uncertain and should probably not be used.

Commercial Groundfish Integrated Fisheries Management Plan (IFMP)

3 Fishery Characteristics

3.1 Longevity

Very short-lived (5 < maximum age < 7)
Short-lived (7 < maximum age < 10)
Moderate life span (10 < maximum age < 20)
Moderately long-lived (20 < maximum age < 40)
Long-lived (40 < maximum age < 80)
Very long-lived (80 < maximum age < 160)
Fig 3 (see Haigh et al 2005, p10). McDermott (1994) estimated the natural mortality rate M to be 0.030-0.039, using the gonad somatic index (GSI) model of Gunderson and Dygert (1988), modified to incorporate updated information for Pacific cod and walleye pollock:M = 0.00876 +1.697 GSI where GSI = ratio of gonad weight to somatic body weight (see Haigh et al 2005, p11). Generation time is roughly 48 years.

3.2 Stock depletion

Crashed (D < 0.05)
Very depleted (0.05 < D < 0.1)
Depleted (0.1 < D < 0.15)
Moderately depleted (0.15 < D < 0.3)
Healthy (0.3 < D < 0.5)
Underexploited (0.5 < D)
Survey indices of abundance are currently not useful for assessing rougheye rockfish population trends. The Hecate Strait assemblage, WCVI shrimp trawl, and NMFS triennial surveys are too shallow. The QCS shrimp survey, while showing an increasing abundance trend, is too limited in areal extent. The QCS synoptic survey, which will become the most reliable, currently has too few data points. The commercial trawl CPUE indices show a slightly increasing trend in 3CD and essentially flat trends in 5AB and 5E (see Haigh et al 2005, Abstract). Catches (Trawl) relatively stable since 1996 (see Table 2, e Haigh et al 2005)

3.3 Resilence

Not resilient (steepness < 0.3)
Low resilience (0.3 < steepness < 0.5)
Moderate resilence (0.5 < steepness < 0.7)
Resilient (0.7 < steepness < 0.9)
Very Resilient (0.9 < steepness)
Forrest ()