Rougheye and blackspotted rockfish complex and longspine thorny management plan 2012: chapter 1

1. Species Information

In April 2007, the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) assessed Rougheye Rockfish (Sebastes aleutianus) as a pair of sympatric species within the known Sebastes aleutianus complex. In the absence of a revised taxonomic classification, these species were named Rougheye Rockfish type I and type II (Gharrett et al. 2004, 2005). Section 1.1 below refers to Rougheye Rockfish types I and II, as originally stated in the original COSEWIC stock status report.

It is now recognized that ‘type I’ refers to Sebastes melanostictus (common name Blackspotted Rockfish), and ‘type II’ refers to Sebastes aleutianus (common name Rougheye Rockfish) (Orr and Hawkins 2008). At present, Fisheries and Oceans Canada (DFO) Science recognizes these two species as distinct (See Section 1.2.1). 

Due to the discovery of previously unrecognized species-level variation in what had been considered the Rougheye Rockfish (S. aleutianus), it is acknowledged that historical biological and catch information on the Rougheye Rockfish includes that of the Blackspotted Rockfish (S. melanostictus). Thus, this management plan will refer to the sympatric species pair as the ‘Rougheye/Blackspotted Rockfish complex’.

Also assessed by COSEWIC in April 2007, was the deep benthic rockfish Longspine Thornyhead (Sebastolobus altivelis). Directed commercial fishing on the species started in 1996, after which its population experienced a typical fishing-induced decline.

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1.1 Species Assessment Information from COSEWIC

This section outlines species information from the 2007 COSEWIC assessment, written based on available knowledge of these species at the time, and does not necessarily reflect the views of Fisheries and Oceans Canada. The technical team acknowledges that this biological information is dated and no longer relevant. For updated species information, please refer to Sections 1.2 to 1.6 of this management plan.

1.1.1 Rougheye/Blackspotted Rockfish Complex COSEWIC Assessment Information

Date of Assessment: April 2007

Common Name (population): Rougheye Rockfish - type I

Scientific Name: Sebastes sp. type I

COSEWIC Status: Special Concern

Reason for Designation: This species is a relatively large (reaching 90 cm in length) rockfish species and among the longest-lived, estimated to approach 200 years. It is one of two sympatric species which have been identified within the described species Sebastes aleutianus. It ranges from northern Japan to southern California in depths 200 to 800 + m along the shelf break. 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.

Canadian Occurrence: Pacific Ocean

COSEWIC Status History: Designated Special Concern in April 2007. Assessment based on a new status report.

Date of Assessment: April 2007

Common Name (population): Rougheye Rockfish - type II

Scientific Name: Sebastes sp. type II

COSEWIC Status: Special Concern

Reason for Designation: This species is a relatively large (reaching 90 cm in length) rockfish species and among the longest-lived, estimated to approach 200 years. It is one of two sympatric species which have been identified within the described species Sebastes aleutianus. It ranges from northern Japan to southern California in depths 200 to 800 + m along the shelf break. 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.

Canadian Occurrence: Pacific Ocean

COSEWIC Status History: Designated Special Concern in April 2007. Assessment based on a new status report.

1.1.2 Longspine Thornyhead COSEWIC Assessment Information

Date of Assessment: April 2007

Common Name (population): Longspine Thornyhead

Scientific Name: Sebastolobus altivelis
COSEWIC Status: Special Concern

Reason for Designation: This slow growing rockfish has adapted to survive in deep waters where oxygen concentrations are minimal and productivity is low. Since the beginning of the fishery in the mid-1990s there has been an estimated decline in commercial catch per unit effort of over 50% in eight years. Fishing is the primary and probably sole cause of this decline. While the fishery is managed by catch limits and monitoring of fishing activities remains comprehensive, there is no management strategy in place that assures catches will be adjusted in response to abundance changes. The substantial decline in abundance indices over a short period taken together with the very conservative life history characteristics are cause for concern, but commercial catch per unit effort may not reflect abundance changes accurately, and there is a small potential for rescue from adjoining populations in the USA. The chief force that is “protecting” Longspine Thornyhead at present is economic.

Canadian Occurrence: Pacific Ocean

COSEWIC Status History: Designated Special Concern in April 2007. Assessment based on a new status report.

1.2 Description of the Species

1.2.1 Description of the Rougheye/Blackspotted Rockfish complex

Rougheye Rockfish belongs to the family Scorpaenidae and its name – rougheye – refers to a series of spines along the lower rim of the eyes. Blackspotted Rockfish also belongs to the family Scorpaenidae. It has recently been concluded through the use of genetic data that rougheye comprises two distinct species – Rougheye Rockfish (Sebastes aleutianus) and Blackspotted Rockfish (S. melanostictus) – with possibly different depth distributions. The two types have similar appearances with slight variations in colour. Hybridization between the two most likely occurs as well.

The archetypal Rougheye Rockfish appears red with dark or dusky blotches of pigment in the back dorsal region. It has a light red lateral line and all but the pectoral fins are usually marked with black ends. The appearance of Blackspotted Rockfish is similar to that of Rougheye Rockfish, but appears darker overall, and can exhibit discrete spots on its spiny dorsal fin, although these are occasionally obscured by dark blotching (Orr and Hawkins 2008).

The Rougheye/Blackspotted Rockfish complex generally does not exceed 80 cm; early records where maximum size was recorded at 97 cm could possibly represent mis-identified shortraker rockfish (S. borealis) (Love et al. 2002). The Rougheye/Blackspotted Rockfish complex are possibly among the longest lived fish species on earth. In Alaska, scientists aged one specimen to 205 years (Munk 2001).

1.2.2 Description of Longspine Thornyhead

Longspine Thornyhead, a rockfish species belonging to the genus Sebastolobus also in the Scorpaenidae family, is a slow growing fish that is adapted for survival in deep waters where oxygen concentrations are minimal and water pressure is high. In Canada’s Pacific waters, Longspine Thornyhead can dominate the fish species that live in deep benthic habitats (> 800 metres below the surface), and likely plays a significant ecological role within this environment. This species has a reddish body and some black on its fins, grows to 39 cm in length, and features large eyes and strong, sharp head spines (Love et al.2002).

1.3 Populations and Distribution

1.3.1 Rougheye/Blackspotted Rockfish complex

The Rougheye/Blackspotted Rockfish complex occurs in the Pacific Ocean north of Japan from the Kamchatka Peninsula to the Bering Sea, the Aleutian Islands, Gulf of Alaska, and the west coast of North America from British Columbia to southern California (Figure 1). Records from the northwestern Pacific are poorly documented (Froese and Pauly 2005).

In BC, the Rougheye/Blackspotted Rockfish complex occurs along the continental slope, and is typically captured at depths between 174 and 640 m. The estimated extent of occurrence in BC, expressed as the area encountered by the groundfish fleet, covers approximately 58,691 km² (Figure 2). There is difficulty in differentiating between the population distributions and abundance for Rougheye Rockfish and Blackspotted Rockfish. Thus, the relative distribution and abundance of the two species in Canadian waters is unknown.

Figure 1. North American distribution of the Rougheye/Blackspotted Rockfish complex. Distribution adjacent to Asian countries is not well documented (Froese and Pauly 2005). Reprinted with permission (Love et al.2002).

Figure 1. North American distribution of the Rougheye/Blackspotted Rockfish complex. (See long description below)
Long description of Figure 1

Figure 1 is a map of the Pacific North American coastline from Alaska to Mexico, highlighting the distribution of Rougheye/Blackspotted Rockfish complex as being north of Japan from the Kamchatka Peninsula to the Bering Sea, the Aleutian Islands, Gulf of Alaska, and the west coast of North America from British Columbia to southern California.

Figure 2. Mean Catch per Unit Effort (CPUE) (kg/h) of BC’s Rougheye/Blackspotted Rockfish complex in grid cells 0.075° longitude by 0.055° latitude (roughly 32 km² each). The shaded cells give an approximation of the area of occupancy (58,691 km²) using fishing events from various fisheries (groundfish bottom trawl, halibut, sablefish, dogfish/lingcod, hook and line rockfish) from Feb 1996 to Jun 2010 (Source: Rowan Haigh, DFO, pers. comm., 2010).

Figure 2. Mean Catch per Unit Effort (CPUE) (kg/h) of BC’s Rougheye/Blackspotted Rockfish complex in grid cells 0.075° longitude by 0.055° latitude (roughly 32 km² each). (See long description below)
Long description of Figure 2

Figure 2 is a detailed image of the estimated extent of Rougheye/Blackspotted Rockfish complex occurrence in Canadian Pacific waters. The image shows the mean CPUE (kg/h) of the Rougheye/Blackspotted Rockfish complex range, in grid cells 0.075° longitude by 0.055° latitude (roughly 32 km² each). The image depicts an approximation of the area of occupancy (58,691 km²), shown in shaded cells, using fishing events from various fisheries (groundfish bottom trawl, halibut, sablefish, dogfish/lingcod, hook and line rockfish) from February 1996 to June 2010.

1.3.2 Longspine Thornyhead

Longspine Thornyhead ranges from Cabo San Lucas, Baja California, to the Aleutian Islands (Figure 3) at depths recorded from 201 to 1,756 m but typically from 500 to 1,300 m (Love et al. 2002). It prefers soft sand or mud bottoms.

Longspine Thornyhead occurs along the continental slope of BC. The most likely ‘extent of occurrence’ lies between the 500 and 1,600 m isobaths with a flat surface area of 17,775 km² (Haigh et al. 2005b) (Figure 4); however, based on observed trawl tows, this area increases to 19,599 km² (Rowan Haigh, DFO, pers. comm., 2010).

Figure 3. North American distribution of Longspine Thornyhead. Distribution adjacent to Asian countries is not well documented (Froese and Pauly 2005). Reprinted with permission (Love et al. 2002).

Figure 3. North American distribution of Longspine Thornyhead. (See long description below)
Long description of Figure 3

Figure 3 is a map of the Pacific North American coastline from Alaska to Mexico, highlighting the distribution of Longspine Thornyhead Rockfish as being from the Aleutian Islands through Cabo San Lucas, Baja California. Distribution adjacent to Asian countries is not well documented.

Figure 4. Mean CPUE (kg/h) of BC Longspine Thornyhead in grid cells 0.075° longitude by 0.055° latitude (roughly 32 km² each). The shaded cells give an approximation of the area of occupancy (19,599 km² ) using fishing events from the groundfish bottom trawl fishery from Feb 1996 to Jun 2010 (Source: Rowan Haigh, DFO, pers. comm., 2010).  Isobaths displayed are 500 m and 1,600 m; the approximate area between these two contours is 17,775 km² (Source: Haigh et al. 2005b).

Figure 4. Mean CPUE (kg/h) of BC Longspine Thornyhead in grid cells 0.075° longitude by 0.055° latitude (roughly 32 km² each). (See long description below)
Long description of Figure 4

Figure 4 is a detailed image of the estimated extent of Longspine Thornyhead Rockfish occurrence along the continental slope in Canadian Pacific waters. The image shows the mean CPUE (kg/h) of the Longspine Thornyhead Rockfish range, in grid cells 0.075° longitude by 0.055° latitude (roughly 32 km² each). The image depicts an approximation of the area of occupancy (19,599 km²), shown in shaded cells, using fishing events from the groundfish bottom trawl fishery from February 1996 to June 2010. The most likely ‘extent of occurrence’ lies between the 500 m and 1,600 m isobaths, also shown on the image.

1.4 Needs of the Species

1.4.1 Habitat and biological needs of the Rougheye/Blackspotted Rockfish complex

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). Boulders may act as territorial markers, current deflectors, or structures that help them hunt for prey (Krieger and Ito 1999). 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).

The biology of the Rougheye/Blackspotted Rockfish complex remains poorly known. The life-span of these species appear to exceed that for most other Sebastes species (Chilton and Beamish 1982). A maximum age of 205 years was recorded for a specimen from southern Alaska (Munk 2001). Females are approximately 20 years old at 50% maturity (McDermott 1994). The principal spawning period off BC occurs in April. Like all ovoviviparous Sebastes species, fertilized eggs remain within the ovary until larval extrusion and may obtain at least some of their nutrition from the female parent during development (DFO 1999). Sebastes larvae occur near the surface where they feed opportunitistically on invertebrate eggs, copepods, and euphausiids; juveniles occur at midwater depths where they feed on larger prey items (Moser and Boehlert 1991). Planktonic larvae of Sebastes can be found up to 500 km offshore from the BC coast, far from adult habitat; however, their midwater residency (200-250 m) as juveniles subjects them to shoreward geostrophic advection (Moser and Boehlert 1991). Currently, there is no evidence to show that larvae and juveniles of the Rougheye/Blackspotted Rockfish complex follow patterns different from those of other Sebastes species.

1.4.2 Habitat and biological needs of Longspine Thornyhead

This species prefers soft sand or mud bottoms in deep-water environments characterized by low productivity (Vetter and Lynn 1997), low diversity (Haigh and Schnute 2003), high pressure, and reduced oxygen concentrations. At these depths, where few species can survive, there is limited food available. Deep-water Longspine Thornyhead has adapted to this environment with extremely slow metabolisms and a sedentary nature that allows it to wait up to 180 days between feedings (Vetter and Lynn 1997).

Populations of Longspine Thornyhead off Oregon and California spawn primarily in the oxygen minimum zone between 600 and 1,000 m (Jacobson and Vetter 1996). Each female Longspine Thornyhead releases from 20,000 to 450,000 eggs (Wakefield 1990) in a buoyant gelatinous matrix. Moser (1974) determined that spawning generally occurs from February to May with a peak in April. Recent data from the MOCNESSFootnote1 program in southern California suggest that Longspine Thornyhead larvae move away from surface waters. Juveniles remain in the water column for approximately 1 year (Moser 1974). Smith and Brown (1983) noted the highest abundance of juvenile Longspine Thornyheads at 600 m in the vicinity of a deep-scattering layer. Thus, the chronology of the pelagic phase (18-20 months) can be generalized:

  1. eggs float to the surface (Feb-May) where they hatch and develop for 3-4 weeks;
  2. larvae move away from the surface but remain in the upper 200 m for 6-7 months;
  3. juveniles remain in the mesopelagic zone (~600 m) for another year.

After the pelagic phase, Longspine Thornyhead juveniles (55 mm average total length, Wakefield and Smith 1990) settle directly into the benthic adult habitat between 600 and 1,200 m, where they reportedly remain (Wakefield 1990).

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1.5 Ecological role

1.5.1 Rougheye/Blackspotted Rockfish Complex

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.

In the Gulf of Alaska, individuals of the Rougheye/Blackspotted Rockfish complex have been reported to consume primarily shrimp (Pandalus borealis, P. montagui tridens, hyppolytids, and crangonids), composing roughly 45-60% by weight of total stomach contents (Yang and Nelson 2000). They also consume fish species, including Walleye Pollock (Theragra chalcogramma), Pacific Herring (Clupea pallasi), Eulachon (Thaleichthys pacificus), Pacific Sandlance (Ammodytes hexapterus), myctophids, zoarcids, cottids, snailfish, and flatfish. In the Gulf of Alaska, fish make up roughly 15-20% of total stomach contents (Yang and Nelson 2000). Additional food items include Tanner Crab (Chionoecetes bairdi), cephalopods, amphipods, mysids, euphausiids, cumaceans, isopods, and polychaetes. While all size-classes of Rougheye/Blackspotted Rockfish complex primarily consume shrimp, fish less than 30 cm have a higher proportion of amphipods in their diet whereas fish larger than 30 cm consume more fish. Krieger and Ito (1999) note that individuals of the Rougheye/Blackspotted Rockfish complex will leave the bottom to capture various prey species.

Predators likely include Pacific Halibut (Hippoglossus stenolepis), Pacific Cod (Gadus macrocephalus), and Sablefish (Amoplopoma fimbria) (Shotwell et al. 2009). 

Figure 5. Abundance of the top 20 species in fishing events that captured at least one individual of the Rougheye/Blackspotted Rockfish complex in the preferred depth range (170–675m).
Top:
trawl tows (1996-2006);
Bottom: hook and line sets (2001-2006). Abundance is expressed as a percent of total weight of all species caught in tows and sets. Source: Haigh et al. (2005a).

Figure 5. Abundance of the top 20 species in fishing events that captured at least one individual of the Rougheye/Blackspotted Rockfish complex in the preferred depth range (170–675m). (See long description below)
Long description of Figure 5

Figure 5 is two graphs showing the abundance of the top 20 species in fishing events that captured at least one individual of the Rougheye/Blackspotted Rockfish complex in the preferred depth range (170–675m). Abundance is expressed as a percent of the total weight of all species caught in groundfish trawl fishery tows (first graph, data from 1996-2006: Pacific ocean perch: 27,20%, Arrowtooth flounder: 24,14%, Dover sole: 17,31%, Rougheye rockfish: 8,77%, Petrale sole: 2,82%, Shortspine thornyhead: 2,80%, Sablefish: 2,32%, Yellowmouth rockfish: 2,12%, Rex sole: 1,05%, Pacific halibut: 1,02%, Redbanded rockfish: 0,93%, Longnose skate: 0,88%, Pacific hake: 0,87%, Spiny dogfish: 0,86%, Silvergray rockfish: 0,79%, Shortraker rockfish: 0,70%, Redstripe rockfish: 0,61%, Sharpchin rockfish: 0,58%, Splitnose rockfish: 0,48%, Walleye pollock: 0,46%) and groundfish hook and line fishery sets (second graph, data from 2001-2006: Rougheye rockfish: 77,50%, Shortraker rockfish: 10,90%, Redbanded rockfish: 6,13%, Silvergray rockfish: 1,74%, Yelloweye rockfish: 1,05%, Lingcod: 0,67%, Spiny dogfish: 0,54%, Shortspine thornyhead: 0,49%, Yellowmouth rockfish: 0,25%, Longnose skate: 0,20%, Thornyheads: 0,17%, Bocaccio: 0,13%, Canary rockfish: 0,06%, Rosethorn rockfish: 0,05%, Pacific ocean perch: 0,05%, Yellowtail rockfish: 0,03%, Arrowtooth flounder: 0,02%, Quillback rockfish: 0,01%, Widow rockfish: 0,01%, Darkblotched rockfish: 0,00%). 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.

1.5.2 Longspine Thornyhead

Longspine Thornyhead co-occur primarily with Shortspine Thornyheads (Sebastolobus alascanus) and Sablefish (Anoplopoma fimbria) (Figure 6). Shortspine thornyhead frequently consume Longspine Thornyhead. As depths increase from those where the two co-occur most densely (500-800 m) to those with oxygen minima and high pressures, S. altivelis gains a competitive advantage through physiological adaptation to extreme conditions, and eventually predominates.

The primary prey species of Longspine Thornyhead pelagic juveniles is probably euphausiids, while settled adults eat the Brittle Star (Ophiophthalmus normani) (Smith and Brown 1983). The adults also consume a variety of other benthic organisms including Grooved Tanner Crabs (small specimens < 30mm carapace width (CW), moulting adolescents < 70mm CW and moulting sub-adults < 110mm CW), myctophids (lanternfish), and small thornyheads (Greg WorkmanFootnote2, pers. comm., COSEWIC stock status report).

Figure 6. Abundance of the top 20 species in trawl tows (1996-2006) that captured at least one Longspine Thornyhead in the preferred depth range (500-1400 m). Abundance is expressed as a percent of total weight of all species caught in the tows. Source: Haigh et al. (2005b).

Figure 6. Abundance of the top 20 species in trawl tows (1996-2006) that captured at least one Longspine Thornyhead in the preferred depth range (500-1400 m). (See long description below)
Long description of Figure 6

Figure 6 is a graph showing abundance of the top 20 species in groundfish trawl fishery tows (1996-2006) that captured at least one Longspine Thornyhead Rockfish in the preferred depth range (500-1400 m). Abundance is expressed as a percent of total weight of all species caught in the tows. Longspine Thornyhead Rockfish co-occur primarily with Shortspine Thornyhead Rockfish (Sebastolobus alascanus) and Sablefish (Anoplopoma fimbria) (Longspine thornyhead: 32,59%, Shortspine thornyhead: 19,75%, Sablefish: 10,80%, Dover sole: 10,78%, Grenadiers: 7,20%, Arrowtooth flounder: 4,93%, Tanner crabs: 4,13%, Deepsea sole: 1,71%, Starfish: 0,82%, Eelpouts: 0,66%, Longnose skate: 0,58%, Rougheye rockfish: 0,44%, Shortraker rockfish: 0,43%, Squids: 0,36%, Pectoral rattail: 0,32%, Pacific grenadier: 0,29%, Roughtail skate: 0,25%, Rex sole: 0,21%, Twoline eelpout: 0,21%, Pacific hake: 0,19%).

1.6 Limiting factors

Limiting factors are intrinsic to the biology of the species, and as such cannot be mitigated or managed. These natural bottom-up and top-down processes are influenced by factors like the availability and quality of prey and the abundance of predators, respectively. However, human activities may contribute pressures that alter these limiting factors, and affect the population or influence its conservation potential.  Limiting factors for the Rougheye/Blackspotted Rockfish complex and Longspine Thornyhead include life history features such as late age of maturity, ocean current-reliant dispersal, cannibalism, vulnerability to capture and barotrauma.

Late age of maturity

Life history features such as late age of maturity (estimated at 20 years for the Rougheye/Blackspotted Rockfish complex and 18 years for Longspine Thornyhead) in these slow-growing, long-lived species could subject Rougheye Rockfish and Longspine Thornyhead to major demographic fluctuations when exposed to natural or anthropogenic (human-induced) disturbances. 

Ocean current-reliant dispersal

Rougheye/Blackspotted Rockfish larvae and Longspine Thornyhead eggs rise to and remain in the upper pelagic zone upon parturition. Thus, the three species’ recruitment success is largely dependent on ocean currents and conditions in the pelagic zone. Pelagic conditions like primary/secondary production strength and timing, upwelling, downwelling, wind velocity and direction, temperature and salinity levels conceivably influence recruitment success. Large-scale atmosphere-ocean fluctuations such as the El Niño-Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO) affect conditions in the pelagic zone and thus produce episodic patterns in year-class success. In addition, as the larvae and juveniles of Longspine Thornyhead and the Rougheye/Blackspotted Rockfish complex spends months in the upper pelagic zone, they are subject to factors like predation and environmental conditions in this zone for that period of time. This has significant implications on the recruitment success of the three species.

Competition and predation

Once the juvenile fish settle into their benthic habitat, they are subject to density dependent factors like competition for food and hiding places, and predation. The situation for Longspine Thornyhead is further aggravated by cannibalism because juveniles settle directly into adult habitat, where the larger fish eat the smaller (Love et al. 2002).

Vulnerability to capture

Larger and older rockfish contribute more to species’ recruitment than smaller and younger rockfish. Large rockfish are known to produce more offspring, while older rockfish produce larvae with higher triglycerol lipid content (Berkeley et al. 2004, Bobko and Berkeley 2004). Higher triglycerol lipid content leads to faster growth rates and greater resistance to starvation, thereby increasing the level of recruitment. However, larger and older rockfish are more vulnerable to fishing gear; therefore, fishing activities may cause greater fluctuations in species recruitment.

Barotrauma

Similar to all Sebastes species, Rougheye and Blackspotted Rockfish have physoclistic swim bladders that cannot rapidly accommodate the sudden change in pressure as they are brought to the surface by fishing gear. The resulting barotrauma causes death for almost all rockfish. DFO Groundfish Management Unit (GMU) recognizes this limiting biological characteristic and as such, has implemented management measures to account for it (see Section 1.8). Longspine Thornyhead, genus Sebastolobus, does not have a swim bladder and thus, does not suffer from barotrauma when captured and brought to the surface.  Its ability to survive temporary exposure to low pressure upon capture and release is unknown. These fish are more likely to die after confinement and compaction in fishing nets for long periods (up to 10 h) (Starr and Haigh 2000).

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1.7 Threats

Assessment of threats to these populations (Table 1) allows for the prioritization of recommended management and other actions to prevent these populations from becoming threatened or endangered. Threats were assessed based on their current likelihood of occurrence and severity of effect to these populations. In addition, the certainty of a population-wide effect was incorporated to provide a measure of confidence in the rating of ‘level of concern’ and to identify threats where further monitoring or study may be useful in addressing uncertainties or knowledge gaps. Where certainty of effect is not demonstrated, weight of scientific evidence for other rockfish species may be deemed adequate to assess the level of concern for a threat.

Anthropogenic threats that cause stress to the Rougheye/Blackspotted Rockfish complex and Longspine Thornyhead include fishing [commercial, recreational, aboriginal FSC (food, social, ceremonial), and research], pollution and climate change. It should be noted that the threat of fishing is historical and current in nature, whereas the threat of climate change is anticipated. In addition, the threat of pollution is plausible, and could be a historical and/or current threat.  The cumulative effect of any combination of these threats (Table 1), in conjunction with species-specific limiting factors (see Section 1.6), may result in consequences more serious than that of any single threat acting upon the population alone.

Threats in Table 1 are prioritized by level of concern, starting with the greatest threat (highest level of concern) to the survival of the species based on the strongest evidence. Each threat’s attributes, such as extent, occurrence, frequency, severity, local or range-wide extent and causal certainty, are all considered to determine the level of concern. Additionally, the ability to mitigate or eliminate the threat may influence the level of concern.

Refer to Appendix I for definitions on threat attributes and related terms used in Table 1.

1.7.1 Threat classification for Longspine Thornyhead and the Rougheye/Blackspotted Rockfish Complex

Table 1. Threat Classification Table
Threat Category General Threat Specific Threat Stress Extent Occurrence: Local Occurrence: Range-wide Frequency: Local Frequency: Range-wide Severity: Local Severity: Range-wide Causal certainty: Local Causal certainty: Range-wide Level of concern: Local Level of concern: Range-wide
Biological Resource Use Fishing Commercial Fishing Reduced population size/viability, local depletion Widespread   Current   Continuous   Medium   High   Medium
Biological Resource Use Fishing Recreational Fishing Reduced population size/viability, local depletion Widespread   Current   Continuous   Unknown   Low   Low
Biological Resource Use Fishing Food Social Ceremonial (FSC) Fishing Reduced population size/viability, local depletion Widespread   Current   Continuous   Unknown   Low   Low
Biological Resource Use Fishing Research Harvest Reduced population size/viability, local depletion Widespread   Current   Recurrent   Low   Low   Low
Climate and Natural Disasters Climate Change Expansion of low-productivity regimes (temporal and spatial) Plankton larvae cannot find enough food; susceptible to increased predation; increasingly unsuitable deep habitat Widespread   Unknown   Unknown   Medium   Medium   Low
Pollution Petroleum spills from tankers; petroleum leaks from sunken vessels; waste from ocean-going vessels Toxins, localized chemical imbalances, anaerobic conditions Increased mortality and loss of reproductive success of the pelagic larval stage Localized Anticipated   Recurrent   Unknown   Low   Low  

1.7.2 Description of threats

Fishing

Harvest of these species may result in reduced population size and viability, and in some circumstances, local depletion of the stock. A threat to the three SARA listed species includes the possibility of overfishing a long-lived species that inhabits a low-productivity environment. The following section further describes the threat of fishing by categorizing the harvest activity as: commercial, recreational, food, social and ceremonial, and research harvest.

i) Commercial Fishing

Directed commercial fisheries for the Rougheye/Blackspotted Rockfish complex and Longspine Thornyhead currently exist; with some historical Rougheye/Blackspotted Rockfish complex commercial fishery records dating back to the 1970s (see Section 1.8).  Given the benthic nature of the complex, it is targeted by the commercial groundfish trawl and hook and line fleets. In contrast, Longspine Thornyhead is primarily targeted only by the commercial groundfish trawl fleet due to its depth range and distribution.

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.

Since the inception of the Longspine Thornyhead ITQ fishery in 1996, the commercial Catch per Unit Effort (CPUE) has declined 6.3 %/year, for a total decline of 60% over fourteen years (Rowan Haigh, DFO, pers. comm. 2010).  Schnute et al. (2004) estimated similar declines for the WCVI region (which accounts for the majority of the BC population) using various models and assumptions (see their Table 9.1, p. 41). These numbers may indicate a fishing-induced decline of a previously unexploited species (removal of accumulated biomass, theoretically associated with increased productivity due to reduced density). Recent reports from the industry suggest that the Longspine Thornyhead fishery has become increasingly less attractive due to falling market prices for this species, increasing fuel costs and the high exchange rate for the Canadian dollar. Combinations of these factors have reduced the directed fishing effort on the species. This is reflected in the annual catch data (Table 3). Future conditions in the fishery, however, cannot be predicted. At this time, little is known regarding removals of rockfish species by commercial non-groundfish fisheries (e.g. prawn by trap, etc.).  

In addition, misidentification for these rockfish species can be problematic, as they are morphologically similar to others in their genus.  This phenomenon was possibly more prevalent during the beginning years of the observer program (Haigh and Schnute 2003), suggesting that the accuracy of catch data has changed over time. However, once observers and dockside monitors gained experience, species identification is assumed to have stabilized. The current difficulty in distinguishing Blackspotted from Rougheye Rockfish will require genetic resolution. It appears unlikely that separation by visual cues will suffice.

Although commercial harvest is the highest known source of mortality, the severity and level of concern of this threat is ‘medium’ given that the actions to mitigate this threat have been implemented and catches are continuously monitored (see Section1.8).

Table 2. Reported annual commercial catches (t), including discards, for Rougheye/Blackspotted Rockfish complex by the five principal groundfish fisheries. Entries marked ‘---’ indicate no reported catch; entries marked ‘0’ indicate catch less than 0.05 t. Catch records for 2010 are incomplete. DFO database sources: PacHarv3, GFCatch, PacHarvest, PacHarvHL, PacHarvSable, GFFOS.
Year Trawl Halibut Sablefish Dogfish Lingcod Hook/Line Rockfish Total
1971
8.6
---
---
---
---
8.6
1972
8.2
---
---
---
---
8.2
1973
---
---
---
---
---
---
1974
---
---
---
---
---
---
1975
---
---
---
---
---
---
1976
14
---
---
---
---
14
1977
77
---
---
---
---
77
1978
140
---
---
---
---
140
1979
218
---
1.4
---
0.5
220
1980
82
---
0.3
---
5.0
88
1981
117
---
---
---
2.1
119
1982
386
---
---
---
---
386
1983
214
---
---
---
0.3
214
1984
346
---
---
---
1.4
347
1985
616
---
---
---
1.9
618
1986
758
---
---
---
---
758
1987
490
---
1.5
---
---
491
1988
1,092
---
5.1
---
---
1,097
1989
1,039
---
---
---
1.7
1,040
1990
1,196
---
1.6
---
19
1,216
1991
997
---
18
---
33
1,048
1992
1,646
---
2.8
---
29
1,678
1993
1,886
---
5.1
---
23
1,915
1994
1,344
---
8.2
---
122
1,474
1995
1,147
1.6
6.1
---
673
1,828
1996
988
17
5.7
1.5
420
1,432
1997
366
23
16
0.2
622
1,027
1998
523
16
7.4
2.5
547
1,096
1999
477
27
14
11
825
1,355
2000
449
135
134
12
771
1,501
2001
498
184
27
0.5
341
1,051
2002
544
163
18
0
355
1,080
2003
509
107
3.1
0.1
375
994
2004
448
143
5.0
0.2
305
901
2005
481
263
17
0.7
197
959
2006
584
178
48
0.2
24
834
2007
649
140
68
0.1
19
875
2008
848
137
50
0.3
72
1,107
2009
951
127
61
0.1
130
1,270
2010
499
79
33
0.1
96
708
Total
22,636
1,741
557
30
6,013
30,976
Table 3. Reported annual commercial catches (t), including discards, for Longspine Thornyhead by the five principal groundfish fisheries.
Entries marked ‘---’ indicate no reported catch; entries marked ‘0’ indicate catch less than 0.05 t. Catch records for 2010 are incomplete. The year 1996 indicates the start of the directed Longspine Thornyhead fishery. However, Longspine Thornyhead has been historically caught with Shortspine Thornyhead as a thornyhead aggregate, prior to being recognized as a distinct species. DFO database sources: PacHarv3, GFCatch, PacHarvest, PacHarvHL, PacHarvSable, GFFOS.
Year Trawl Halibut Sablefish Dogfish Lingcod Hook/Line Rockfish Total
1996
876
0
---
---
---
876
1997
752
---
---
---
---
752
1998
876
---
---
---
---
876
1999
966
---
---
---
---
966
2000
847
---
---
---
---
847
2001
678
---
---
---
1.9
680
2002
696
0
---
---
0.5
696
2003
437
---
---
0
0
437
2004
327
---
---
---
---
327
2005
69
---
---
---
---
69
2006
291
0
---
---
---
291
2007
177
---
---
---
---
177
2008
63
---
---
---
---
63
2009
97
---
0
---
---
97
2010
76
---
---
---
---
76
Total
7,227
0
0
0
2.4
7,230
ii) Recreational Fishing

Where recreational fishing gear reaches depths at which the population resides, this activity can have an impact on these species. Given the benthic and offshore nature of Longspine Thornyhead, and the specialized gear necessary to harvest the species, it is assumed that recreational catch is minimal. On the other hand, interaction between recreational gear and the Rougheye/Blackspotted Rockfish complex may be more common given that it occurs at shallower depths.

Recreational rockfish catches are currently managed using daily and in-possession bag limits, which vary among statistical management areas and time periods. Although there are no records of Rougheye/Blackspotted Rockfish complex catch in the Department’s recreational creel surveys, rockfish species identification is poor in this fishery and thus, catches of these species are not explicitly distinguished from those reported as “mixed rockfish” or “other rockfish”. Anecdotal information confirms that rockfish species are often caught incidentally by some recreational fish harvesters while they target more popular species such as salmon or Pacific halibut (Hippoglossus stenolepis).

As it is difficult to assess the impact of the recreational fishing sector, the severity of the threat is unknown. However, given the depth range at which the Rougheye/Blackspotted Rockfish complex and Longspine Thornyhead reside, it is unlikely that the species is commonly encountered by recreational harvesters. The level of concern is therefore considered to be ‘low.’

iii) First Nations Food, Social and Ceremonial (FSC) Fishing

First Nations FSC fisheries occur throughout the coastal waters of British Columbia. Detailed catch data for these fisheries are currently not available. Due to the lack of verified FSC catch for these species, the severity of the threat is unknown.  However, given the depth range and distribution of these rockfish species, it is assumed that the impact of FSC fisheries and level of concern is considered to be ‘low.’ Anecdotal information suggests that neither species are of any significant social nor ceremonial value, as such, harvest is assumed to be minimal.

iv) Research Harvest

DFO Science, in conjunction with the commercial groundfish industry and the International Pacific Halibut Commission (IPHC), organizes and conducts a suite of research surveys to assess the status of groundfish stocks on the BC Coast. These surveys vary in duration, frequency, objectives, targeted species and methodology.

Catch of all species is recorded on most research surveys, and data (Table 4) are stored in a DFO electronic database (GFBio). A survey identifier table called ‘C_Activity’ lists most of the surveys in GFBio (there may be surveys entered but not identified by an explicit activity code). Currently, research survey catches are not included in the Rougheye/Blackspotted Rockfish complex and Longspine Thornyhead stock assessments because catch is considered minimal. The severity of this threat is considered to be ‘low’ in relation to existing continuous forms of harvest, resulting in a ‘low’ level of concern.

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Table 4. Research surveys and their catches (t) of the Rougheye/Blackspotted Rockfish complex and Longspine Thornyhead.
The ACTIVITY_CODE field in GFBIO’s C_Activity table covers most, but not all surveys.
Years indicate when surveys caught these species.
Activity Code Activity Description Years Rougheye/Blackspotted Rockfish complex (t) Years Longspine Thornyhead (t)
1 Trawl biomass survey  
---
 
---
2 Larval survey  
---
 
---
3 Hydroacoustic survey 1997
0.008
 
---
4 Biological sampling survey 1997
0.008
 
---
5 Submersible survey  
---
 
---
6 Nearshore Rockfish survey  
---
 
---
7 Oceanographic survey  
---
 
---
8 Seamount survey  
---
 
---
9 Trap biomass survey 1991-2001
4.913
1999-2001
0.012
10 Dive survey  
---
 
---
11 Tagging  
---
 
---
12 Hecate strait multispecies trawl survey 1987,2002-03
0.020
 
---
13 Goose Island gully pop trawl survey 1966-1995
3.033
 
---
14 West Coast Vancouver Island thornyhead trawl survey 2001-2003
0.074
2001-2003
12.330
15 Strait of Georgia hake survey 2001
0.044
 
---
16 West Coast Vancouver Island hake survey 1995-2001
0.062
 
---
17 Hecate Strait PCOD monitoring trawl survey  
---
 
---
18 Yelloweye rockfish charter longline survey 1997-2003
5.902
 
---
19 Sablefish research and assessment survey 1991-2010
17.040
1999-2010
0.050
20 Jig survey  
---
 
---
21 Queen Charlotte sound synoptic trawl survey 2003-2009
5.238
2004-2009
0.114
22 West Coast Vancouver Island synoptic trawl survey 2004-2010
3.457
2004-2006
0.030
23 Inshore rockfish longline survey  
---
 
---
24 IPHC longline survey 2003-2009
4.323
 
---
25 Shellfish section shrimp survey 1976-2010
1.231
1994, 2008
0.383
26 Hecate Strait synoptic trawl survey 2005-2009
0.443
 
---
27 West Coast Queen Charlotte Island synoptic survey 2006-2010
48.124
2006-2010
1.422
28 PHMA longline surveys 2007-2009
0.243
 
---
29 Hecate Strait juvenile flatfish survey  
---
 
---
30 Hake stock delineation 2008
0.018
 
---
31 Joint CAN/US hake accoustic survey 1995-2009
0.178
2009
0.007
Total Species catch (t) using GFBIO codes 1966-2010
94.359
1994-2010
14.349

Note: There is a mirror database called GFBioSQL, which additionally contains a field called SURVEY_SERIES ID for bootstrapping purposes.

Expansion of Low-Productivity Regimes (Temporal and Spatial)

The larvae of the Rougheye/Blackspotted Rockfish complex and Longspine Thornyhead can spend months in the upper pelagic zone. Thus, species’ survival is subject to conditions within that zone, which are affected by productivity drivers such as the El Niño-Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO). As juvenile dispersal of the Rougheye/Blackspotted Rockfish complex and Longspine Thornyhead relies on ocean advection, changes in currents and upwelling may directly affect the recruitment levels, leading to episodic patterns in year-class success.

Climate change and large-scale regime shifts can affect north Pacific ecology (e.g., Beamish and Bouillon 1993, McFarlane et al. 2000, Benson and Trites 2002). Recent research suggests that a global decline in phytoplankton has been linked to increasing sea surface temperatures (Boyce et al. 2010). As rockfish larvae feed on zooplankton (that ultimately depend on phytoplankton) in the pelagic phase of their life cycle (Moser and Boehlert 1991), a reduction in phytoplankton would result in decreased prey availability, compromising the survival of juvenile Rougheye, Blackspotted Rockfish and Longspine Thornyhead.

It is also plausible that large-scale changes brought about by shifts in climate could have varying impacts on the habitat and geographical distribution of these fish species. For example, declining ocean productivity possibly due to sea surface temperature increases could reduce the distribution of the Rougheye/Blackspotted Rockfish complex (current range extends as far south as Oregon).  In addition, recent studies have suggested causal linkages between global warming and the vertical and horizontal expansion of oxygen minimum zones (OMZs) in the ocean. The OMZ is a regular feature of mid-depths. The expansion of OMZs in the past decade (Stramma et al. 2010) has lead to increasing incursions of low oxygen water onto the productive continental shelves (e.g., Bograd et al. 2008, Chan et al. 2008).

Although the severity of this threat is considered to be ‘medium’, the occurrence of the phenomenon of climate change and its resultant threats are ‘unknown’. In addition, the ability to mitigate this threat is low. As such, further research may be necessary to identify and quantify the impacts on these rockfish species caused by climate change.  In relation to the other existing identified threats to these rockfish populations, the level of concern is considered to be ‘low’.

Toxins, Localized Chemical Imbalances and Anaerobic Conditions

The threat of pollution could originate from petroleum spills from oil tankers, petroleum leaks from sunken vessels or waste from ocean-going vessels. Waste discharges from the latter are recurrent events along the BC coast, and the likelihood may increase with high densities of traffic. Ocean-going vessels are permitted to dump grey water and heated sewage, which affects water quality in the pelagic zone. In addition, primary production and prey availability of the Rougheye/Blackspotted Rockfish complex and Longspine Thornyhead could be severely compromised by the introduction of synthetic and non-biodegradable pollutants in the environment.

Although measures to prevent and mitigate effects of spills are currently in place, once a spill occurs the effectiveness of clean up measures typically falls between 5 to 15% (Graham 2004), and is highly dependent on proximity to population centres with facilities and expertise for cleanup.

As the severity of this threat is largely ‘unknown’, further research may be necessary to identify its plausibility and severity. The level of concern of this threat is considered to be ‘low.’

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1.8 Actions Already Completed or Underway

Commercial Groundfish Integration Program (CGIP)

Since 2003, the Department has focused on working with the commercial groundfish harvesters and others to address management and sustainability issues in the commercial groundfish fisheries. The Department identified five guiding principlesFootnote3 for the commercial groundfish sector:

  1. All rockfish catch must be accounted for.
  2. Rockfish catches will be managed according to established rockfish management areas.
  3. Fish harvesters will be individually accountable for their catch.
  4. New monitoring standards will be established and implemented to meet the above three objectives.
  5. Species and stocks of concern will be closely examined and actions such as reduction of TACs, and other catch limits will be considered and implemented to be consistent with the precautionary approach for management. 

Following significant work through the Commercial Groundfish Industry Advisory Committee (CGIAC) and the Commercial Industry Caucus (CIC), a three year pilot was introduced in the commercial groundfish fisheries in 2006. The reforms focus on 100% at-sea monitoring and 100% dockside monitoring, individual vessel accountability for all catch, both retained and released, individual vessel quotas (IVQs) and reallocation of these quotas between vessels and fisheries to cover catch of non-directed species.

The pilot program has now been completed and the 2010/2011 commercial groundfish fishing season marks the first year of full implementation. A comprehensive evaluation of the CGIP was conducted in 2009 and results show that the program is achieving the Department’s conservation objectives and satisfies social concerns and economic performance (DFO 2009a).

The commercial groundfish industry plays an active role in fisheries management through scientific collaboration, including significant funding towards research surveys, observer coverage, electronic and dockside monitoring of vessels.

Groundfish Science Research Surveys

DFO Groundfish Science currently conducts four synoptic trawl surveys in collaboration with the Canadian Groundfish Research and Conservation Society (CGRCS). The initial synoptic survey was conducted in Queen Charlotte Sound in 2003 and has since collected data to generate five annual index values from 2003 to 2009. Following the success of this endeavour, similar synoptic surveys were initiated for the west coast of Vancouver Island in 2004; Hecate Strait and Dixon Entrance in 2005, and the west coast of Haida Gwaii in 2006.

The hook and line fisheries rely on a different set of surveys, the primary ones being (i) the jig surveys (1984-1993), (ii) Yelloweye Rockfish charter longline survey (1997-2003), (iii) inshore rockfish longline survey (2003-2008), (iv) IPHC longline survey (2003-2009), and (v) Pacific Halibut Management Association (PHMA) longline survey (2006-2009).

Additionally, there are the shrimp surveys off the west coast of Vancouver Island (1976-2010) and near shore in Queen Charlotte Sound (1998-2010). These sometimes prove useful for the shallower rockfish or juveniles of the deeper rockfish. Depending on the species, any combination of the surveys listed in Table 4 is potentially useful.

Consolidation of Databases

Harvest and research data are currently housed in numerous databases on various platforms. Oracle databases include PacHarv3, GFBIO, and GFFOS. SQL Server databases comprise GFCatch, PacHarvest, PacHarvHL, PacHarvSable, and GFBioSQL. Additionally, there are scattered databases that reside solely on individual work stations (e.g. Historical_Catch.mdb that includes data from manuscripts and spreadsheets (Haigh and Yamanaka in prep.), NFMS Triennial Survey data for the Vancouver Island region). It is anticipated that the consolidation of databases will allow effective management and access to fisheries data.

2000 – 2006 Exploratory Longspine Thornyhead Fishery – Management Actions

Prior to 2000, under the IVQ management program, DFO set a single coastwide Total Allowable Catch (TAC) for Longspine Thornyhead. While the quota was coastwide, the trawl industry concentrated its fishing effort to deep waters off the west coast of Vancouver Island (WCVI). In that area, Longspine Thornyhead catch accounted for more than 70% of the total combined shortspine and Longspine Thornyhead catch. It was thought by the industry that Longspine Thornyhead stocks in other areas of the coast contained significant abundance. However, these areas were not exploited due to difficult terrain, strong tides, high bycatch levels (e.g. sablefish) and high fishing costs.

In 2000, DFO reduced the coastwide TAC by more than 50% as a precautionary measure, due to a decline in commercial Longspine Thornyhead CPUE from initial levels in areas of catch concentration, as well as a lack of stock assessment advice. In addition, DFO (in conjunction with the industry) initiated an exploratory program to encourage a shift in fishing effort from the WCVI to fishing grounds further north, by providing additional fishing opportunities coupled with increased biological sampling requirements. The biological data collected was intended for use in analyses of population age structure, growth and reproduction. These analyses would then produce more reliable estimates of stock abundance and long-term productivity, since it was noted that the commercial CPUE data was influenced significantly by fishing behaviour.

Further management actions were taken in 2002 with the creation of five management regions, and the implementation of a large area closure to provide refuge to a proportion of the population. The exploratory program was discontinued in 2006, and the fishery reverted back to the reduced coastwide TAC level as a result of a significant reduction in fishing effort.

Directed Rougheye/Blakspotted Rockfish Complex Seamount Fisheries – Management Actions

In 1992, the Department permitted a directed rockfish (by hook and line) fishery on Bowie Seamount. The Rougheye/Blackspotted Rockfish complex composed the bulk of the rockfish catch and was a targeted species for several years. In 2006, due to the introduction of ITQs, 100% catch monitoring requirements in the rockfish hook and line fleet, and interests by the Department to establish the Bowie Seamount as a Marine Protected Area (MPA), the directed fishing effort for the Rougheye/Blackspotted Rockfish complex at Bowie ceased.

At present, there is an active directed Sablefish fishery that occurs on the offshore seamounts (including Bowie). The Sablefish seamount fishery is monitored through 100% at-sea and dockside monitoring programs, and indirect catches of the Rougheye/Blackspotted Rockfish complex are permitted through monthly vessel limits. From 2007 to 2009, Rougheye/Blackspotted Rockfish complex landings averaged about 8000 pounds per year for all seamounts combined (Adam Keizer, DFO, Halibut and Sablefish coordinator, pers. comm. 2010).

Sponge Reef Closures, National Marine Conservation Areas (NMCAs) and Marine Protected Areas (MPAs)

In 2007, DFO, with support of the groundfish trawl industry, implemented three sponge reef closures with the intent of providing protection for four identified unique glass sponge reef ecosystems. These sponge reef closures are located in the waters (approximately 200 m deep) of the eastern Queen Charlotte Sound and Hecate Strait, and are closed year round to all bottom trawling. It is likely that the dense coverage of sponge reefs provides shelter to the juveniles and young adults of the Rougheye/Blackspotted Rockfish complex. Due to the depth range and offshore distribution of Longspine Thornyhead, it is less likely that this species seeks refuge here. A conservation strategy for coldwater corals and sponges has recently been approved by the Department.

The Canada National Marine Conservation Areas Act provides for the establishment of National Marine Conservation Areas (NMCAs). In 2010, the Gwaii Haanas NMCA was established as a joint initiative of  Parks Canada, DFO, and the Council of Haida Nation. The development of an integrated fisheries management plan for this NMCA is currently underway.

Additionally, under Canada’s Oceans Act, DFO has designated two Marine Protected Areas (MPAs) – the Endeavour Hydrothermal Vents and the Bowie Seamount – within the coastal waters of BC. NMCAs and MPAs are intended to protect and improve the resilience of ecosystems, and can contribute to local fishery sustainability through the enhanced survival of large productive females and potential future dispersal of young fish from the protected area to outside fishing areas. As such, these protected areas may help conserve slope rockfish species such as the Rougheye/Blackspotted Rockfish complex and Longspine Thornyhead.

Collaborative Research Projects

DFO regularly collaborates with individuals from related branches of academia on various research projects that facilitate a better understanding of the challenges facing fishery managers and research scientists today.

For example, NSERC (National Science and Engineering Research Council) recently initiated a project to assess the potential impacts of bottom-fishing gear on seafloor habitat. Physical and biological characteristics of benthic marine habitats often play an important role in supporting the production of marine species.  Therefore, managing disturbances of bottom habitat is a necessary criterion for assessing fishery sustainability and will help the fishing industry design operational changes to mitigate these impacts.

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1.9 Knowledge Gaps

Biological Information on the Rougheye/Blackspotted Rockfish Complex

The recently discovered existence of two species within what was formerly known as Rougheye Rockfish (Jordan and Evermann 1898), and the resultant lack of biological knowledge (including distribution and threats) of the Rougheye/Blackspotted Rockfish complex could constitute a threat in itself, since cryptic species of this kind increase the risk of losing unrecognized genetic diversity. 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.

Orr and Hawkins (2008) redefined the two species taxonomically and provided diagnostic markers for distinguishing S. aleutianus (Rougheye) and S. melanostictus(Blackspotted). Their findings suggest that the distribution of Rougheye Rockfish is confined to the eastern Pacific Ocean whereas that for Blackspotted Rockfish ranges across the North Pacific from Japan to California. The authors assert that although they are morphologically similar, there are consistent colour pattern differences on the body between the two species with Blackspotted Rockfish always exhibiting discrete spots on its spiny dorsal fin (though these are occasionally obscured by dark blotching) while Rougheye Rockfish has an overall pale colour with no discrete spots. Orr and Hawkins derived a discriminant function using morphometric and meristic characters, that claims to correctly classify the two species 97.8% of the time. At this time, aside from the discriminant function and DNA analysis, there are no other known methods for distinguishing the two species accurately.

Currently, 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 between the two species. Currently, genetic samples of the complex are taken on some DFO Science surveys. A pilot study is underway to determine a cost-effective means for routinely identifying the catches, and the complexity of genetic analysis required to distinguish the two species and their hybrids (Rick Stanley, DFO, pers. comm., 2010). Genetic sampling will necessarily become a regular feature of all future surveys, and the additional cost will be on-going. Sampling the commercial catch will likely be more complicated, but protocols should be developed if the two species need to be accurately identified in commercial catch removals. In the interim, species composition ratios derived from the genetic sampling of the complex on DFO Science surveys may be used to estimate commercial catch composition.

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.

It is anticipated that given time and resources, more will be known about the abundance and distribution of Rougheye/Blackspotted Rockfish complex.

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