1           Introduction

This report addresses issues recently raised by the Canadian Sablefish Association (CSA) concerning the anticipated development of the sablefish aquaculture industry in British Columbia. In particular, the CSA is concerned with the potential risks associated with marine net pen sablefish grow out operations. Many of the issues raised are similar to those stemming from the ongoing debate about the impacts of salmon aquaculture in British Columbia. Detailed summaries of the environmental risks of salmon farming already exist. For example, a report by the Commissioner for Aquaculture Development (Anon., 2004) includes reviews of three recent reports: a PFRCC study on the salmon aquaculture debate in British Columbia (Gardner and Peterson, 2003); a NOAA funded study of the net pen salmon farming industry in the Pacific northwest (Nash, 2001); and the 11 volumes included in the "Salmon Aquaculture Review" of the British Columbian Environmental Assessment Office (Anon., 1997). Similar reviews exists for salmon farms outside British Columbia (e.g., Olivier and MacKinnon, 1998; Scottish Association for Marine Science and Napier University, 2002). Rather than re-iterating what has already been published, the following comments and opinions focus primarily on problems that may be of particular significance in the sablefish aquaculture context. The comments are guided by the 1988 Memorandum of Understanding (MOU) between federal and provincial governments. Under the MOU, the federal Department of Fisheries & Oceans (DFO) is responsible for: identifying areas where fish farming can occur; aquaculture research; fish health and inspection; and imposing measures to protect and conserve wild fish and their habitats. The British Columbia government is responsible for aquaculture development and regulation activities.

Sablefish are ecologically distinct from the fish species that are currently being reared commercially in British Columbia (i.e., salmonids). While at sea, adult salmon keep relatively close to the surface, whereas sablefish are typically caught at depths of 500 to 1500 m (Beamish and McFarlane, 1988). Salmon juveniles rear in rivers or in estuaries, whereas juvenile sablefish spend their first 2-5 years in coastal inlets (DFO, 2003), in close proximity to the proposed sablefish net pen locations. Salmon enter rivers and deposit eggs in the substrate, whereas sablefish, which are marine broadcast spawners (Mason et al., 1983), are capable of spawning within the net pens, releasing spawning products into the local waters where they can potentially mix with wild stocks. As such, genetic contamination of wild stocks may more likely result from sablefish farm than from salmon, even in the absence of farm-escapees. These life-history differences need be considered in order to assess the potential environmental effects of sablefish aquaculture. Any environmental impact assessments that are not designed specifically to address the problems of sablefish aquaculture are not likely to adequately identify the problems. Moreover, any management decisions about sablefish aquaculture that are based solely on our knowledge of salmon farming could lead to unexpected or disastrous consequences for the wild resource.

Some potential risks to the wild resource include: the risk of disease or parasite transfer from net pen fish to wild stocks (from escaped fish or because of close proximity of farm sites to juvenile nursery grounds); the loss of valuable juvenile sablefish habitat to new or existing sablefish farms; the pollution of juvenile rearing habitat from farm sewage and fish feeds; the impacts on wild resources from drugs and pesticides used at aquaculture sites; and the genetic interaction between wild sablefish and farmed sablefish (and the potential loss of genetic diversity). Given the potential risk to the wild resource, the precautionary approach would dictate that an environmental impact assessment should be conducted before farmed sablefish are allowed in marine net pens.

This report will discuss each of the CSA's issues with regard to the potential risks of marine net pen sablefish grow out operations. The important questions will be identified, the published literature will be reviewed, and potential research directions will be suggested. We conclude that there are real risks that need to be addressed before marine net pen sablefish aquaculture is permitted in British Columbia.

2           The Precautionary Approach to Sablefish Aquaculture Development

Salmon aquaculture development in British Columbia was accompanied by federal and provincial environmental monitoring activities to determine the magnitude and types of impacts on wild species and their habitats. Despite this, and the availability of considerable background information on salmon biology and ecology, the Auditor General of Canada (AGC) recently pointed out that the DFO "was not carrying out its current regulatory responsibilities to enforce the Fisheries Act with respect to farming operations," and, "there were shortfalls in research and monitoring to assess the effects of salmon farming operations," and, "had not put in place a formal plan for managing risks and for assessing the potential cumulative environmental effects of proposals for new sites" (Anon., 2000a). A cursory review of recent developments indicates that little has been done since the AGC review to rectify this situation. Interestingly, Noakes et al. (2000) echoed similar views on the DFO failure to protect wild salmon stocks from the negative impacts of publicly funded salmon hatchery operations in British Columbia.

In contrast to salmon aquaculture, little is known about sablefish aquaculture. Still, the provincial government recently issued several amendments to existing salmon aquaculture licenses, allowing sablefish to be raised at some salmon farming sites. It would seem reasonable to request that standard environmental and risks assessments be conducted before sablefish grow-out sites are licensed, sited, stocked and operated, so the situation described by the AGC is not duplicated, and so that the UN’s Precautionary Approach (FAO, 1996; Porter et al., 1998) is applied in a responsible fashion with regard to the regulated expansion of this new industry. The current situation seems to support the legitimate and justified concerns expressed by the CSA about allowing untested sablefish farming practices to take place in close proximity to wild sablefish rearing habitats and fishing grounds.

Past studies on salmon farm aquaculture operations provide useful insight on mechanisms by which rearing practices can impact on wild species and their habitats, but there is no substitute for sablefish-specific rearing studies, farm monitoring and impact assessments. The current knowledge base on sablefish aquaculture is clearly insufficient to conduct even a crude qualitative impact assessment. It may take years before the necessary studies yield the information needed to quantify potential impacts with some level of certainty. In the interim, at a minimum, an adaptive management plan (Walters, 1986) should be implemented to learn by direct manipulation of pilot farming operations (under safe/strict conditions), but even such a plan has yet to be formulated and agreed upon by representatives of industry, government and First Nations.

3           The Potential Ecological Risks

Assessments of the ecological risks associated with sablefish net pen culture should be designed to address the concerns outlined in the following sections. 

3.1          Risk of disease or parasite transfer from net pen fish to wild stocks

The main issue concerning sablefish rearing at this stage is determining the susceptibility of penned and wild sablefish to disease or parasites. Since the sablefish net pens will likely be in proximity to existing salmon farms, transfer of pathogens between salmon and sablefish is also of concern.

Sablefish farms and hatcheries can act as vectors for the transmission and amplification of various pathogens, including parasites, bacteria, fungi and viruses. Typically, the pathogens which affect fish in net pens occur naturally in wild fish (Kent, 2000). As such, wild fish are clearly susceptible to the transfer of pathogens from net pen fish back to their natural hosts. In the wild, infected animals are removed by predators at the first sign of weakness (Crawley, 1992). However, in a net pen, infected fish are protected from predators and live longer than they would in the wild, potentially shedding greater volumes of pathogen into the water. Since there is no way for the healthy farm fish to physically separate themselves from the infected fish, the risk of further infection (and possibly epidemic) increases. Moreover, crowding and handling can cause stress responses in captive fish, which can lead to increased susceptibility to disease (see Crosa, 1983). Pathogens could potentially be transmitted from infected farms to the wild sablefish when the farm sites are in close proximity to juvenile nursery grounds (i.e., pathogens get transferred to the wild juveniles) and when escaped farmed fish interact with wild individuals.

A number of observations of diseased sablefish have been documented in the scientific literature. For example, Gores and Prentice (1984) reared 39 sablefish in marine net pens for two years. Disease-related mortalities were attributed to furunculosis (Aeromonas salmonicida) and Vibrio anguillarum. Furunculosis was also reported for rearing experiments conducted at the Pacific Biological Station (Kennedy, 1974). Eight batches of sablefish (from 30 to 373 fish per batch) were reared in separate 3000 L tanks. Furunculosis was diagnosed in three of the eight tanks (Kennedy, 1969, 1970, 1974; Kennedy and Smith, 1971, 1972, 1973), and was present, but not properly diagnosed in a fourth (Kennedy and Smith, 1972). Infection reached epidemic levels in one of the batches (Kennedy and Smith, 1972); that for which stocking density was highest. The strain of Aeromonas salmonicida which caused the furunculosis at the Pacific Biological Station has also been found in wild trawl-caught sablefish (Evelyn, 1971) and in two species of cultured Pacific salmon. Infection transmitted via sea water has been demonstrated (Scott, 1968).

Gores and Prentice (1984) also reported lesions (5 to 8 mm in diameter) at the base of the pectoral fins, operculum and/or anal fin, at times affecting 40% of the penned individuals. The lesions, which the authors could not attribute to any apparent cause, lasted from one to seven months, with greatest intensity from September through December.

In a study of salmonid pathogens found in ocean-caught fishes in British Columbia, Kent et al. (1998) examined 33 sablefish of which four were diagnosed with epitheliocystis, and two were found to be infected with the protozoan parasite Loma. Brocklebank (1996) reported papillomatosis in a farmed sablefish. Papillomatosis is caused by a retrovirus, and results in the growth of epidermal tumors on the skin and scales. The tumors may occur at any site on the body surface and can be 5 mm thick and 4 cm in diameter. Fish that are heavily infested with the tumors may succumb to other secondary bacterial, viral, or fungal infections. No methods of treatment or control are known.

Approximately 38% of the fish reared by Gores and Prentice (1984) became blind in at least one eye, several of which developed severe eye infections causing the eyes to protrude. Similar eye problems were reported by Kennedy (1969).

Moser and Noble (1976) described the occurrence of a myxosporean protozoan parasite (Leptotheca informis) in the gall bladder of a wild-caught sablefish. Moser (1976) described a new myxosporean species found the gall bladders of three individual wild-caught sablefish, and named the new species Ceratomyxa anoplopoma after its host. The copepod Lepeophtheirus parviventris and the larvae of the nematode Phocanema decipiens have also been described in sablefish (Kabata, 1973; Hoskins et al. 1976; both summarized in Margolis and Arthur, 1979). Kabata and Whitaker (1984) examined 30 sablefish specimens and found 14 species of parasite, including seven trematodes, four nematodes, and one each of Cestoda, Acanthocephala and Copepoda. Kabata et al. (1988) found seven species of trematode in 419 sablefish from 13 locations. Whitaker and McFarlane (1997) examined 246 sablefish and found 10 species of parasites of which several had not yet been recorded in sablefish (see Table 1).

Table 1.     List of parasites described in sablefish hosts. Sources are: Moser (1976); 2: Moser and Noble (1976); 3: Margolis and Arthur, 1979; 4: Kabata and Whitaker, 1984); 5: Kabata et al., 1988; and 6: Whitaker and McFarlane (1997).

In addition to these published accounts, the DFO Fish Health Laboratory researchers have recorded the presence of 24 different diseases and parasites in cultured and wild sablefish (Table 2 DFO, unpublished data[1]). Appendix A provides a brief description of the main sablefish diseases that have been reported in the literature or that appear in DFO's database. Many of the diseases are common to salmonid populations (Roberts and Shepherd, 1986) including furunculosis, Vibriosis, Viral Hemorrhagic Septicemia, and Bacterial Kidney Disease.

Table 2.     Diseases and parasites found in wild and cultured sablefish as diagnosed by the DFO Fish Health Laboratory at Pacific Biological Station, Nanaimo, British Columbia. Eighty-three sablefish were examined.

Many of these pathogens can have a major effect on sablefish health, survival and the ability to reproduce. Although vaccines exist for two of the most commonly observed pathogens (furunculosis and Vibriosis; W. C. Clarke[2], pers. comm.), there are others that can be potentially devastating to the wild resource (e.g., Bacterial Kidney disease, Viral Hemorrhagic Septicemia). Sablefish demography is such that a few large year classes contribute heavily to the spawning biomass, and the fishery is dependent on large, periodic recruitment events (Sigler et al., 2001; McFarlane and Beamish, 1986). As such, an outbreak of a serious disease among juvenile sablefish occurring in the "wrong year" could affect recruitment and hence the fishery for many subsequent years (i.e., until the next big recruitment year).

It is clear from the preceding treatment that sablefish can be afflicted with several varieties of muscle, eye and gill parasites. Though many such parasites are non-lethal, they can reduce growth rates and hence fecundity (fecundity is a function of size; Mason et al., 1983; Macewicz and Hunter, 1994). Moreover, muscle parasites can affect the appearance and texture of the meat and hence affect the market value of the fish.

Given that sablefish culture is still in its infancy (i.e., no large-scale facilities are yet operating), relatively few fish have been reared, and hence only a few of the potential problems have been identified. In general, farmed fish are susceptible to many diseases that are seldom seen under natural conditions, and that only becomes a problem when fish are kept under different environmental conditions (Kent, 2000). As such, the diseases that have been reported in the literature, and that are shown in Table 2 likely represent only a small portion of the diseases and parasites to which sablefish are susceptible.

To our knowledge, no studies have been performed to investigate the risk of disease transfer between nearshore salmon net pen operations and the juvenile sablefish that reside in the nearby inshore habitat. Since the proposed sablefish net pen sites will be located in nearshore environments, since juvenile sablefish are known to enter net pens, and since adult and juvenile sablefish will likely be susceptible to all the diseases that afflict adult sablefish, it would be prudent to focus research efforts on identifying those diseases or pathogens that can be readily transferred between farm sablefish and wild juveniles. Given the potential risk to wild fish, these initial investigations should be conducted in a laboratory facility or in land-based tanks.

In order to get a more complete understanding of the types of diseases that can affect sablefish under commercial rearing conditions, it may be necessary to hold large numbers for extended periods of time. Again, the potential risk of wild-stock contamination precludes experimentation in nearshore net pens. As such, any large-scale holding and rearing trials should be conducted in a land-based facility.

What follows is a number of potential experiments that could be conducted to address some of the important questions about disease transfer. These examples are meant to provide a starting point for discussions about how the necessary questions about sablefish disease transfer can be addressed.

One potential group of experiments could be carried out in a land-based tank which is large enough to contain a scale-model net pen which would occupy a minority of the tank volume (as the rest of the tank would simulate the waters surrounding a net pen site). Control fish would be put in the main part of the tank, and Experimental fish would be put into a scale-model net pen. As such, the Experimental fish would be restricted to a smaller volume and would experience higher stocking density than the Control fish. To examine whether caged fish are more susceptible to disease than wild fish, a number of diseased sablefish could be introduced into the tank. The diseased fish could be introduced into the tank at large (to explore transfer of disease from wild to caged fish) or into the net pen (to explore transfer of disease within the net pen). Rates of infection would be compared between the "farmed" and "wild" populations. It may be favorable to use juvenile sablefish as the Control group.

If it is found that caged sablefish are more likely to contract diseases / parasites than wild individuals, then experiments should be designed to determine what the appropriate stocking densities should be to avoid serious disease outbreaks. In an experimental tank similar to that described above, the densities in the model net pen can be varied from trial to trial to determine acceptable stocking densities. Control fish should be stocked at densities similar to that found in the embayments near the proposed net pen sites.

It may be difficult to directly assess how far the net pens should be from the juvenile rearing habitat to minimize disease transfer. However, the effluent from a tank containing diseased fish could be diluted to smaller and smaller concentrations to mimic a net pen being located farther and farther away. Tanks of wild juvenile sablefish could be subjected to one of a variety of these dilutions, and the rates of infection could be used to determine the dilution required to minimize risk to the wild fish. Given information about flushing in the nearshore environment, distances can be calculated from dilutions, to give an estimate of the minimum distance that pens should be placed away from the juvenile rearing habitat in the nearshore inlets.

3.2          Risk of disease introduction from the importation of exotic species, eggs and milt

The best way to prevent the disease-introduction when placing farmed sablefish into nearshore marine waters is to ensure that all milt, eggs and/or juveniles that are used to seed sablefish farms come from the local area. The use of local origin fish is recommended because there have been several cases in recent history in which the translocation of fish from a localized population into a novel area has resulted in rampant disease outbreaks that wreaked havoc on the local wild stocks. For example, furunculosis was introduced to Norway in the 1980s following the importation of Atlantic salmon smolts from Scotland, and has had significant impact on the wild stocks (Johnsen and Jensen, 1994).

Another reason that local fish should be reared is related to the possibility that sablefish are genetically adapted to local conditions. Local adaptation has been documented to evolve quickly (Hendry et al., 2000), and genetic population structure is common in marine broadcast spawners (e.g., Ruzzante et al., 1999). When local fish are reared, the problems associated with genetic interaction between farmed and wild fish are minimized (see Section 3.7).

There is a need to ensure that the adequate egg fertilization practices are used in hatcheries (if used to supply farms) to ensure that the sablefish produced have levels of genetic diversity akin to those generated via natural spawning events. Also, there is a need to determine if there are pathogens in the flesh, eggs or milt that can be transmitted to hatchery environments and eventually to sablefish farms when these are stocked. It may be prudent to require disease-free certifications for any sablefish eggs that enter a hatchery (similar to those for the salmon industry with respect to IHN). The critical sablefish pathogens must first be identified (see Section 3.1).

3.3          Risk of disease transfer between domestic farmed and wild species

This issue is partly addressed in Section 3.1 above. If farmed sablefish are particularly susceptible to some pathogens, one could logically deduct that wild sablefish may also be susceptible to the same pathogens. However, to demonstrate that there is a significant risk to the wild population(s), one must show that the pathogen can be transmitted via some vector (birds, boats, divers, fish, currents, etc.). Experiments need to be carried out to identify these mechanisms.

3.4          Pollution of habitat from fish sewage

It seems reasonable to assume that all fish farming operations in coastal waters off British Columbia will be subject to the same regulations concerning the allowable discharges (type, amount), irrespective of the species raised. The issue of concern to the sablefish industry is how much waste (mortalities, feces, uneaten food, chemical, etc.) is typically generated over a certain period by a typical operation. Studies need to be conducted to determine how discharge rates and composition of sablefish farming operations (and supporting hatcheries) compare to those of salmon farming operations.

3.5          Loss of juvenile habitat

Ideally, surveys should be conducted before the proposed grow-out sites are operated to determine the usual densities of wild juvenile sablefish in the area, and the environmental attributes of the area. At a minimum, this would provide pre-impact data needed to determine the impact (if any) of the aquaculture operation on the wild population and their habitats. It would be prudent, at least initially, to restrict aquaculture operations to sites located more than a set minimum distance from known juvenile sablefish rearing areas. This would comply with the Canadian Fisheries Act, administered by DFO, which requires "no harmful alteration, disruption or destruction of fish habitat" resulting from industrial activity or development. This act also requires that the DFO takes measures to protect "critical fish habitats," which includes areas used for rearing and migration of wild fish. This would also reduce the potential for direct contact and disease transfer between wild and farmed sablefish.

3.6          Impacts on wild resources from drugs and pesticides used at aquaculture sites

At this stage it has not been yet been shown that certain sablefish rearing conditions (typical and/or crowded/stressful) require drugs, antibiotics, pesticides and other chemicals. As for the other chemicals, it seems reasonable to expect that government regulations will likely apply to all marine farming operations irrespective of the species raised. Initial research should focus on the chemical supplements (type, dose, etc.) required for typical sablefish farming operations, and determine suitable siting locations.

3.7          Genetic interaction between wild and farmed fish

Large-scale, commercial sablefish rearing practices have not yet been established, and it is possible that maturing farmed sablefish would spawn in the net pens. The potential impacts are difficult to predict given the lack of information about the viability of the products of shallow-water, near-shore sablefish spawning. It is not known if sablefish can produce viable gametes at shallow depths. It is not known if the fragile sablefish eggs will be able to survive in the more turbulent waters near-shore (see Alderdice et al., 1988). Differences in behaviour and growth rate between wild juveniles and those that result from net pen spawning are unknown, hence it is difficult to predict how effectively domestic offspring will compete with wild juveniles in the near-shore nursery grounds. Studies are needed to address these issues.

In addition to net pen spawning, there is a possibility of genetic interaction resulting from the mixing of wild and escaped farmed fish on the spawning ground. There is currently no information available that addresses this issue. It is not known whether escapees will forage properly since they would be habituated to eating pellets. If the escapees survive, it is not known whether they will migrate to spawning grounds. Controlled feeding studies, coupled with an experimental escapee tagging program should be done to investigate these issues.

One way to avoid the issues associated with genetic interactions is to allow only sterile sablefish to be used for aquaculture purposes (assuming sablefish can be sterilized), at least initially. Note that since sterile escapees may still compete with wild mature sablefish for food or other resources (leading to a potential loss in productivity), escapes should nevertheless be deterred as effectively as possible.

It should be noted that the mixing of locally resident spawners with a non-local (farmed escapee) would produce less viable offspring under two scenarios: 1) local adaptation; and 2) domestication.

Local Adaptation

In the first scenario, the wild fish must be genetically adapted to their local environments, such that spawning with non-locals would result in offspring that are genetically maladapted to the local conditions. For local adaptations to manifest, and for genetic differences to be maintained, individuals must home to the same spawning ground each year (or show year-round site fidelity), such that there is little mixing of local populations during the spawning season. Homing has not been demonstrated in sablefish, though year-round site fidelity may occur as 75-80% of tagged Vancouver Island and Queen Charlotte Sound sablefish were recaptured up to nine years later less than 50 km from the locale at which they were tagged (Beamish and McFarlane, 1988). Nevertheless, straying rates (the proportion recaptured more than 200 km away) were large enough (10-12%) for genetic panmixis (assuming the strays spawn in their new location), and there is yet no conclusive proof of genetic population structure in North American sablefish.

The single published study on sablefish genetics (Gharrett et al., 1983), a preliminary report, indicated that some genetic substructure may exist, but the results were inconclusive because the sablefish were not collected during the spawning period, when any existing sub-populations are most likely to be physically separated. The lead author believes that his paper has many shortcomings, and hopes to use newly developed techniques (described in Matala et al., 2004) to revisit the data in a more rigorous manner (A. J. Gharrett[3], pers. comm.). Meanwhile, Beamish and McFarlane (1988) referred to the only other genetic study of sablefish by quoting personal communications from G. Winans and G. Stauffer at the NW and Alaska Fisheries Center (Seattle, WA), writing that they have completed an "extensive comparison" which "concluded that, in general, sablefish stocks are one population." A shortcoming of the study, similar to that of Gharrett et al. (1983), is that the analysed sablefish were not collected during the spawning period. Winans' paper is now in manuscript form and is currently undergoing peer review (G. A. Winans[4], pers. comm.).

The use of parasites as biological tags is a well-established technique for differentiating fish stocks (e.g., Sherman and Wise, 1961). When parasites are restricted to a particular area by the environmental requirements of their intermediate hosts (e.g., molluscs, etc.), any movement of the host fish from the location of infection can be detected. As such, fish from different localities can be distinguished by their parasite assemblage. Two studies have explored the use of parasites as biological tags for sablefish (Kabata and Whitaker, 1984; Whitaker and McFarlane, 1997). These studies found limited movement of sablefish among seamounts (Whitaker and McFarlane, 1997) and little exchange of sablefish between seamounts and the continental shelf (Kabata and Whitaker, 1988). Both studies concluded that the sablefish occupying offshore seamounts should be considered discrete populations. Neither study has been able to identify population structure within the continental shelf sablefish.

The issue of local adaptation is as yet unresolved,. To address the issue, tagging should be conducted only during spawning season, and recaptures should only be considered when made during subsequent spawning seasons. However, storms (Sigler et al., 2001) preclude heavy fishing effort in Alaska during the spawning season (peak spawning occurs in February; Mason et al., 1983), hence the probability of detecting long-distance strays is low. A genetic study of wild sablefish population structure, based on samples taken during the spawning season, would help resolve this issue.

Domestication

The mixed spawning of wild spawners with escaped farm fish would produce less viable offspring, regardless of the degree of genetic population structure, if selection pressures put on the farmed population results in domestication. It should not be surprising that farmed fish experience direct and indirect selection pressures which results in evolution toward larger sizes, smaller fins, faster growth, increases in aggressive and risk-prone behaviour (Fleming and Einum, 1997; Fleming et al., 2002), and whatever mal-adaptive side-effects these bring. In the wild, survival rates of farm-escaped salmonids are poor, relative to wild fish, as are those of the F1 hybrids, and the third generation backcrosses (McGinnity et al., 2003). As such, productivity of the wild stock can be severely reduced if they interbreed with mal-adapted domestic farm-escapees. The degree of domestication that will occur in farmed sablefish is not yet known, nor is the relative survival rates of wild, farmed, and hybrid offspring. Studies should be conducted to help resolve these issues.

4           Other Concerns

In addition to ecological concerns, the potential for sablefish aquaculture development raises concerns of an economic and regulatory nature. The CSA's concerns with this regard are outlined in the following sections.

4.1          Loss of access to traditional fishing grounds

It is unlikely that sablefish fish farms will be located in exposed areas over deep water in relative proximity to sablefish fishing grounds off the west coast of British Columbia. The potential impact on other fisheries could be minimized by establishing scientifically defensible buffering distances between net pen locations and fishing grounds.

4.2          Illegal rearing of wild fish in net pens

Uncontrolled sablefish farming operations provide opportunities for the rearing and sale of wild fish caught in excess of the aquaculture quota (if any) for the provision of brood stock. The aquaculture industry should be required to participate in a rigorous accounting and monitoring system as a condition of license, so that the rearing of illegally caught fish is discouraged. This could be achieved in part by requiring that all farmed raised sablefish be tagged for identification purposes.

4.3          Use of lights to attract wild juvenile sablefish for capture or feed

Some salmon farms are illuminated after sunset to induce feeding at night. It has been reported that lights attract wild pre-juvenile salmon that do not always enter the pens. However, small sablefish have been reported to enter illuminated salmon pens. Sablefish pens may not require nighttime illumination, but if they did, it is hypothesized that farmed sablefish would readily prey on smaller sablefish that enter. It is conceivable that sablefish farm operators may operate lights that attract juvenile sablefish in order to reduce feeding and/or farm seeding costs. These issues should be investigated to determine the rearing practices that minimize predation on wild juvenile sablefish. Regulations regarding rearing practices should ensure that pens are not located, designed or operated to attract and catch large numbers of wild juvenile sablefish.

4.4          Illegal harvesting of fish at aquaculture sites due to inadequate monitoring and enforcement

Oyster farming operations, and abalone rearing sites (for example) are prone to peculiar types of vandalism, abuse, pirating and illegal exploitation. There is no reason to believe that sablefish grow-out sites won’t be subject to problems that are unique in some respect. Assuming that the DFO will retain responsibility over the enforcement of regulations, the CSA should be concerned with the adequacy of financial and human resources available to fishery officers. The resources currently allocated by the DFO for aquaculture monitoring activities is perceived by many to be insufficient (including some fishery officers that cannot be named for confidentiality purposes), and the expansion of the aquaculture industry may simply compound existing problems leading to obvious conclusions.

4.5          Reallocation (without compensation) of fully utilized commercial fishery quotas to the aquaculture sector

If sablefish farmers seed pens with juveniles produced in hatcheries, then only eggs and milt will be required, which should not amount to a substantial portion of the live catch. If farmers opt to raise (i.e., fatten) small fish caught in traps, the number of live fish requested by the sablefish aquaculture industry could represent a significant and increasing portion of the total allowable catch (TAC). Studies are needed to determine how many fish would be required by sablefish farmers in the near future, and what portion of the TAC this amounts to. Note that the DFO would have to approve the retention of small sablefish, which seems unlikely given that it is already requiring certain mesh sizes to allow small fish to escape from traps.

4.6          Negative impacts on coastal communities and unique coastal ecosystems

This is a general concern that must be addressed in the context of an overall coastal resource management plan for regions with planned sablefish farming operations. The selection of potential sites must take into account the concerns of the local communities and any unique or sensitive coastal ecosystems close to the proposed sites.

4.7          Negative impacts to agricultural land and fresh water wells

This issue would only apply to rearing facilities located on land. Specific regulations and routine monitoring of any land based aquaculture facilities are required to ensure that potential impacts are insignificant.

4.8          Rapid expansion of supply resulting in landed price reductions

Gislason (2001) indicates that sablefish aquaculture would likely require 20 years to fully develop, and that the maximum impact on sablefish prices would be a reduction of 40%. However, the CSA could request that farmed sablefish be labeled as a farmed product to distinguish it from wild sablefish. The consumer may prefer wild sablefish, especially if the farmed sablefish are shown to taste differently because they are fed pellets, colorants, and antibiotics.

5           Recommendations

A precautionary approach should be used to regulate the expansion of the industry in the face of considerable uncertainty regarding impacts on wild populations of aquatic organisms and their habitats. Consequently, even in the absence of scientific evidence to prove that certain factors have negative impacts on wild fish stocks, the DFO is obliged to exercise real caution when allowing certain activities to proceed. This includes restraining fishery exploitation, dam construction, hydro-electric power production, oil & gas exploration activities, effluent discharges, as well as hatchery and aquaculture operations. Ironically, only the latter two activities seems to be allowed to proceed/expand with minimal constraints, despite the fact that these may induce significant increase in natural mortality and genetic impacts that are commensurate with those caused by excessive exploitation, habitat loss and industrial pollution.

Research related to the key impact issues for sablefish aquaculture should be conducted prior to the licensing of commercial aquaculture operations. This research should be carried out in a systematic manner, starting with controlled studies in laboratories or land-based tanks before progressively moving to net pen studies in the marine environment. Ideally, this research should be a collaborative effort involving the CSA, those invested in sablefish aquaculture, and the federal, provincial, municipal and First Nations governments. The first step in this effort would be to formulate and agree on a five year research and development (R&D) plan. The initial focus for the research component of the plan would be to acquire the information needed to conduct a rigorous assessment of the potential impacts and risks associated with alternative approaches to the development of a sablefish aquaculture industry.  The results would then serve to set scientifically defensible regulations and monitoring requirement for the industry.

5.1          Next steps

We propose that representatives from the CSA, aquaculture industry, and appropriate government agencies meet to discuss the need and approaches for the development of a R&D plan for sablefish aquaculture.  Once agreed, a steering committee should be established to guide the development of the plan and subsequent research.  Each of the participating parties would be asked to provide a portion of the funds required to hire the technical expertise required to prepare and review the plan.     It is expected that this process will draw on technical expertise from government, universities, colleges and private industry.  The plan would include cost estimates for all recommended research and development activities, and identify funding sources and other in-kind support for these activities.

6           Literature Cited

Alderdice, D. F., Jensen, J. O. T., and Velsen, F. P. J. 1988. Incubation of sablefish (Anoplopoma fimbria) in a system designed for culture of fragile marine teleost eggs. Aquaculture 71: 271-283.

Anonymous. 1997. Salmon aquaculture review. British Columbia Environmental Assessment Office. 11 volumes.

Anonymous. 2000a. The effects of salmon farming in British Columbia on the management of wild salmon stocks. Report of the Auditor General of Canada. December 2000. p. 30:5-30.

Anonymous. 2000b. Atlantic Salmon Papillomatosis (retrovirus). Fish Health Issues 2 (11): http://www.maine.gov/ifw/fishing/fishlab/vol2issue11.htm. Updated November, 2002.

Anonymous. 2004. Recommendations for change. Report of the Commissioner for Aquaculture Development to the Minister of Fisheries and Oceans Canada. Canadian Dept. of Fisheries & Oceans. Cat no. Fs-23-441/2004E-PDF.

Beamish, R. J., and McFarlane, G. A. 1988. Resident and dispersal behavior of adult sablefish (Anaplopoma fimbria) in the slope waters off Canada's west coast. Can. J. Fish. Aquat. Sci. 45: 152-164.

Brocklebank, J. R. 1996. Papillomatosis of a farmed black cod in British Columbia. Can. Vet. J. 37: 556.

Crawley, M. J., editor. 1992. Natural enemies: the population biology of predators, parasites and diseases. Blackwell Scientific Publications, Boston, MA. 576 p.

Crosa, J. H., editor. 1983. Bacterial and viral diseases of fish: molecular studies. Washington Sea Grant Program, Seattle, WA. 86 p.

DFO. 2003. Sablefish. DFO Can. Sci. Advis. Sec. Stock Status Rep. 2003/031: 5 p.

Evelyn, T. P. T. 1971. An aberrant strain of the bacterial fish pathogen Aeromonas salmonicida isolated from a marine host, the sablefish (Anoplopoma fimbria), and from two species of cultured Pacific salmon. J. Fish. Res. Board Can. 28: 1629-1634.

FAO. 1996. Precautionary approach to capture fisheries and species introductions. FAO Technical Guidelines for Responsible Fisheries, 2: 54 p.

Ferguson, H. W. 1989. Systematic pathology of fish. Iowa State University Press, Ames, IA. 263 p.

Fleming, I. A., and Einum, S. 1997. Experimental tests of genetic divergence of farmed from wild Atlantic salmon due to domestication. ICES J. Mar. Sci. 54: 1051-1063.

Fleming, I. A., Agustsson, T., Finstad, B., Johnsson, J. I., and Björnsson, B. T. 2002. Effects of domestication on growth physiology and endocrinology of Atlantic salmon (Salmo salar). Can. J. Fish. Aquat. Sci. 59: 1323-1330.

Gardner, J. G., and Peterson, D. L. 2003. Making sense of the salmon aquaculture debate. Analysis of issues related to netcage salmon farming and wild salmon in British Columbia. Report submitted to the Pacific Fisheries Resource Conservation Council. 159 p.

Gharrett, A. J., Wishard, L. N., and Thomason, M. A. 1983. Progress in the study of the biochemical genetics of sablefish. p. 143-146 In Proceedings of the International Sablefish Symposium. Lowell Wakefield Fisheries Symposia Series. Ed. Melteff, B. R. Alaska Sea Grant Rep. 83-8.

Gislason, G. S. 2001. Halibut and sablefish aquaculture in BC. Economic potential. Report for the BC Ministry of Agriculture, Food and Fisheries, Victoria, BC. 26 p.

Gores, K. X., and Prentice, E. F. 1984. Growth of Sablefish (Anoplopoma fimbria) in Marine Net Pens. Aquaculture 36: 379-386.

Hendry, A. P., Wenburg, J. K., Bentzen, P., Volk, E. C., and Quinn, T. P. 2000. Rapid evolution of reproductive isolation in the wild: Evidence from introduced salmon. Science 290: 516-518.

Hoskins, G. E., Bell, G. R., and Evelyn, T. P. T. 1976. The occurrence, distribution and significance of infectious disease and neoplasms observed in fish in the Pacific Region up to the end of 1974. Fish. Mar. Serv. Res. Dev. Tech. Rep. 609: 37 p.

Isshiki, T., Nishizawa, T., Kobayashi, T., Nagano, T., and Miyazaki, T. 2001. An outbreak of VHSV (viral hemorrhagic septicemia virus) infection in farmed Japanese flounder Paralichthys olivaceus in Japan. Dis. Aquat. Org. 47: 87-99.

Johnsen, B. O., and Jensen, A. J. 1994. The spread of furunculosis in salmonids in Norwegian rivers. J. Fish Biol. 45: 47-55.

Kabata, Z. 1973. The species of Lepeophtheirus (Copepoda: Caligidae) from fishes of British Columbia. J. Fish. Res. Board Can. 30: 729-759.

Kabata, A., and Whitaker, D. J. 1984. Results of three investigations of the parasite fauna of several marine fishes of British Columbia. Can. Tech. Rep. Fish. Aquat. Sci. 1303.

Kabata, A., McFarlane, G. A., and Whitaker, D. J. 1988. Trematoda of sablefish, Anoplopoma fimbria, (Pallas, 1811), as possible biological tags for stock identification. Can. J. Zool. 66: 195-200.

Kennedy, W. A. 1969. Sablefish culture - a preliminary report. Tech. Rep. Fish. Res. Board Can. 107: 20 p.

Kennedy, W. A. 1970. Sablefish culture - progress in 1969. Tech. Rep. Fish. Res. Board Can. 189: 17 p.

Kennedy, W. A. 1974. Sablefish culture - final report. Tech. Rep. Fish. Res. Board Can. 425: 15 p.

Kennedy, W. A., and Smith, M. S. 1971. Sablefish culture - progress in 1970. Tech. Rep. Fish. Res. Board Can. 243: 18 p.

Kennedy, W. A., and Smith, M. S. 1972. Sablefish culture - progress in 1971. Tech. Rep. Fish. Res. Board Can. 309: 17 p.

Kennedy, W. A., and Smith, M. S. 1973. Sablefish culture - progress in 1972. Tech. Rep. Fish. Res. Board Can. 388: 8 p.

Kent, M. L. 2000. Marine netpen farming leads to infections with some unusual parasites. International Journal of Parasitology 30: 321-326.

Kent, M. L., Traxler, G. S., Kieser, D., Richard, J., Dawe, S. C., Shaw, R. W., Prosperi-Porta, G., Ketcheson, J., and Evelyn, T. P. T. 1998. Survey of salmonid pathogens in ocean-caught fishes in British Columbia, Canada. J. Aquat. Anim. Health 10: 211-219.

Kortet, R., Vainikka, A., and Taskinen, J. 2003. Effect of epidermal papillomatosis on survival of the freshwater fish Rutilus rutilus. Dis. Aquat. Org. 57: 163-165.

Macewicz, B. J., and Hunter, J. R. 1994. Fecundity of sablefish, Anoplopoma fimbria, from Oregon coastal waters. California Cooperative Oceanic Fisheries Investigations Reports 35: 160-174.

Margolis, L., and Arthur, R. 1979. Synopsis of the parasites of fishes of Canada. Bull. Fish. Res. Board Can. 199.

Mason, J. C., Beamish, R. J., and McFarlane, G. A. 1983. Sexual maturity, fecundity, spawning, and early life history of sablefish (Anoplopoma fimbria) off the Pacific coast of Canada. Can. J. Fish. Aquat. Sci. 40: 2126-2134.

Matala, A. P., Gray, A. K., Heifetz, J., and Gharrett, A. J. 2004. Population structure of Alaskan shortraker rockfish, Sebastes borealis, inferred from microsatellite variation. Environ. Biol. Fish. 29: 201-210.

McFarlane, G. A., and Beamish, R. J. 1986. Production of strong year-classes of sablefish (Anoplopoma fimbria) off the west coast of Canada. INPFC Bull. No. 47: 191-202.

McGinnity, P., Prodohl, P., Ferguson, K., Hynes, R., O'Maoileidigh, N., Baker, N., Cotter, D., O'Hea, B., Cooke, D., Rogan, G., Taggart, J., and Cross, T. 2003. Fitness reduction and potential extinction of wild populations of Atlantic salmon, Salmo salar, as a result of interactions with escaped farm salmon. Proc. R. Soc. Lond. Ser. B 270: 2443-2450.

Moser, M. 1976. Ceratomyxa anoplopoma sp.n. (Protozoa, Myxosporida) from the sablefish, Anoplopoma fimbria. Can. J. Zool. 46: 1405-1406.

Moser, M., and Noble, E. R. 1976. The genus Leptotheca (Protozoa, Myxosporida) in macrourid fishes and sablefish, Anoplopoma fimbria. J. Protozool. 23: 490-492.

Nash, C.E. [ed.]. 2001. The net-pen salmon farming industry in the Pacific northwest. U.S. Dept. Commer., NOAA Tech. Memo. NMFS-NWFSC-49. 125 p.

Noakes, J. N., Beamish, R. J., and Kent, M. L. 2000. On the decline of Pacific salmon and speculative links to salmon farming in British Columbia. Aquaculture 183: 363-386.

Nowak, B. F., and Clark, A. 1999. Prevalence of epitheliocystis in Atlantic salmon, Salmo salar L., farmed in Tasmania, Australia. J. Fish Dis. 22: 73-78.

Olivier, G., and MacKinnon, A.-M. 1998. A review of potential impacts on wild salmon stocks from diseases attributed to farmed salmon operations. Can. Stock Assess. Sec. Res. Doc. 98/159: 12 p.

Olsson, J. C., Jöborn, A., Westerdahl, A., Blomberg, L., Kjelleberg, S., and Conway, P. L. 1998. Survival, persistence and proliferation of Vibrio anguillarum in juvenile turbot, Scophthalmus maximus (L.), intestine and faeces. J. Fish. Dis. 21: 1-9.

Porter, R., Carey, T., Harris, D., and Coombs, K. 1998. A review of existing conventions, regulations, and policies pertaining to the control and minimization of negative impacts from aquaculture on wild salmonid stocks. Can. Stock Assess. Sec. Res. Doc. 98/164: 19 p.

Ramsay, J. M., Speare, D. J., Sánchez, J. G., and Daley, J. 2001. The transmission potential of Loma salmonae (Microspora) in the rainbow trout, Oncorhynchus mykiss (Walbaum), is dependent upon the method and timing of exposure. J. Fish. Dis. 24: 453-460.

Roberts, R. J., and Shepherd, C. J. 1986. Handbook of trout and salmon diseases, 2nd edition. Fishing News Books Ltd., Farnham, Surrey, England. 222 p.

Ruzzante, D. E., Taggart, C. T., and Cook, D. 1999. A review of the evidence for genetic structure of cod (Gadus morhua) populations in the NW Atlantic and population affinities of larval cod of Newfoundland and the Gulf of St. Lawrence. Fish. Res. 43: 79-97.

Scott, M. 1968. The pathogenicity of Aeromonas salmonicida (Griffin) in sea and brackish waters. J. Gen. Microbiol. 33: 263-274.

Scottish Association for Marine Science and Napier University. 2002. Review and synthesis of the environmental impacts of aquaculture. Scottish Executive Central Research Unit. 80 p.

Sigler, M. F., Lunsford, C. R., Lowe, S. A., and Fujioka, J. T. 2001. 2001 Groundfish stock assessment and fishery evaluation document, Alaska Sablefish Assessment for 2002. NPFMC SAFE Document. sec. 9.

Sherman, K., and Wise, J. P. 1961. Incidence of the cod parasite Lernaeocera branchialis, in the New England area, and its possible use as an indicator of cod populations. Limnol. Oceanog. 6: 61-67.

Walters, C. J. 1986. Adaptive management of renewable resources. Macmillan Publishing Company, New York, NY. 374 p.

Whitaker, D. J., and McFarlane, G. A. 1997. Identification of sablefish, Anoplopoma fimbria (Pallas, 1811), stocks from seamounts off the Canadian Pacific Coast using parasites as biological tags. p. 131-136 In Biology and Management of Sablefish, Anoplopoma fimbria. Ed. Wilkins, M. E. and Saunders, M. W. NOAA Tech. Rep. NMFS 130.

Appendix A.    Notes about the cause, effects and infectiousness of several diseases and parasites found in wild and cultured sablefish. Sources are: 1: Crosa (1983); 2: Roberts and Shepherd (1986); 3: Ferguson (1989); 4: Olsson et al. (1998); 5: Nowak and Clarke (1999); 6: Anon. (2000b); 7: Isshiki et al. (2001); 8: Ramsay et al. (2001); and 9: Kortet et al. (2003).