Trawl Industry Comments on the PSEIS

Chapter 3, Volume II Section 3.2

  • “Fishing Gear Effects on Substrates and Benthic Communities”

Chapter 3, volume II Section 3.2 “Fishing Gear Effects on Substrates and Benthic Communities” sets the baseline that the PSEIS uses to describe the effects of alternative fishing gears on benthic habitat and thus build a rationale for the benefits it ascribes to the habitat protection alternatives in the PSEIS. The sub-section on effects of bottom trawling is in need of significant revision to more objectively reflect the weight of scientific opinion and evidence. In our view, the subsections on effects of groundfish gears other than trawl need to be modified and the section on trawl effects needs to be completely revamped. Such modifications would make the later sections that describe habitat management alternatives more objective and likely lead to general reconsideration of the habitat alternatives that were proposed (see comments on habitat alternative 5).

Comments on Sections –

  • Bottom Trawl Patterns in the Bering Sea, Effects of Bottom Trawling in the Bering Sea, Trawling Patterns in the Gulf of Alaska and Aleutian Islands, Trawling Effects in the Gulf of Alaska, Trawling Effects in the Aleutian Islands

These mostly informational sections amount to a mixture of a description of the history of trawling off Alaska, what is known about its relative intensity, and descriptions of some of the efforts that have been made to study the effects of trawling in the Gulf of Alaska, Bering Sea, and Aleutian Islands.

Regarding the facts presented in the SEIS describing the history of trawling off Alaska, several sources have documented significant catches of groundfish by motorized trawling off Alaska conducted by Japan and other countries as early as the 1950s (Megrey and Wespestad 1990, SEIS Table 2.7-1). In fact, steam trawling off Alaska started about the same time it commenced off Europe, thus the statement that the trawl fisheries began in the 1960s should be revisited.

While the information presented about what is known of the relative intensity of trawling off Alaska is valuable, the discussion of areas (such as Kodiak Island and Unimak Pass) where trawling is described as relatively intense should be more carefully presented. The fact that the concept of relative intensity is expressed in terms of a comparison to the other areas off Alaska should be made clear to the reader.

This is important because some may interpret the notion of relative intensity in terms of a comparison to fishing off Europe or the eastern United States. While no formal estimates of trawling intensity on a detailed spatial scale are provided in the SEIS, the average number of trawl tows reported in the SEIS tables per unit area suggests a relatively low trawl density and intensity compared to other shelf areas in the United States and around the world ((Rijnsdorp et al. 1998 (North Sea), Piet et al. 2000 (North Sea), Pitcher et al. 2000 (Australia), Auster et al. 1996, (Georges Bank)). Specifically, fishing effort in the Bering Sea was indexed on a 100 km2 grid, indicating that fishing effort at this scale is highly concentrated in specific areas, while the majority of the Bering Sea experienced low or very low trawl intensities (PSEIS, Fig. 3.2-1). Fishing effort in the GOA was quantified (number of trawls per km2) on a 25 km2 grid, suggesting a similar concentration of fishing effort in certain areas, while large areas of the shelf experienced low density trawling on average from 1990-1998 (PSEIS, Fig 3.2-3, 3.2-4).

Comments on Section

  • General Observations on Trawling Applicable to the North Pacific Ocean

The bottom trawl effects summary attempts to interpret and synthesize the findings of a variety of works from a scientific literature survey. An extensive body of scientific literature on the effects of trawling exists and different studies present markedly different conclusions about the effects of trawling on benthic habitat. This section effectively attempts to decide which literature and which literature survey piece is most correct in its findings, which is most relevant to the groundfish fisheries and habitat off Alaska, and how the selected general conclusion can be reconciled with the scant scientific work that has evaluated trawl effects off Alaska. We find serious flaws and biases to this portion of the SEIS, which are discussed below.

This section effectively adopts the controversial conclusions of a paper by two east coast researchers, professors Auster and Langton (Auster and Langton 1999). While parts of the Auster and Langton (1999) paper which evaluate the findings of acute and chronic (instantaneous and long term) physical effects of trawling are less controversial, the SEIS essentially embraces the conclusion that bottom trawling necessarily reduces habitat complexity and benthic bio-diversity to the detriment of sustainable fish stocks based mostly on the findings of that one literature survey (Auster and Langton 1999). This sets the course for SEIS Section and the development of habitat alternatives that follow in later sections.

While the Auster and Langton (1999) piece is one opinion on what the body of scientific work reveals about trawl effects, other works on trawl effects may be equally or more relevant to the North Pacific ocean. For instance, as an alternative to the Auster and Langton (1999) paper, SEIS authors could have relied on the conclusions reached in one of the most encompassing studies of trawl effects (Hall 1999) which evaluates what is known about different types of physical effects on substrates and benthic communities. Regarding evidence for long-term trends in benthic communities in the North Sea, studies presented in Hall (1999) lead to the conclusion that “the case for invoking fisheries as a primary cause for the recorded changes is not very strong” (Hall 1999).

Other reviews (ICES 2000, Collie et al. 2000, ICES 1988, Hutchings 1990, Messieh 1991, etc.) have evaluated what is known about trawling and reached the conclusion that trawl effects depend greatly on the type of trawl gear, type and depth of substrate fished, degree of natural disturbance, fishing intensity, and other factors. To our knowledge, no published review paper prior to or subsequent to the Auster and Langton (1999) paper has claimed that available scientific studies establish that trawling irrevocably reduces habitat complexity and benthic diversity in all cases.

For purposes of background information, when the Auster and Langton (1999) paper was released, it attracted and has continued to attract considerable criticism from the scientific community regarding the paper’s tendency to replace scientific methods of treating information with methods more often associated with advocacy campaigns. In fact, many scientists with training and experience in marine ecology effectively dismiss the Auster and Langton (1999) paper as simply the well-publicized credo of Dr. Auster and his colleagues who work closely with the American Oceans Campaign’s public relations efforts to ban or restrict bottom trawling.

While most of this controversy came from the paper itself, this matter certainly became more convoluted when it also came to light after the paper was published that much of Dr. Auster’s work is funded in large part by the Pew Charitable Trusts, an endowment which openly funds marine advocacy campaigns attempting to ban bottom trawling (for evidence that Dr. Auster’s work is funded by the Pew Charitable Trusts, one can go to University of Connecticut’s web site page at:

Although literature survey papers and their use in analyses such as this one should ideally only be judged on their scientific merits, the near complete acceptance and reliance on the Auster and Langton (1999) paper for this section of the SEIS is disturbing. Further, the rather anemic reasons offered in the SEIS for dismissing or attempting to downgrade the relevance of other scientific literature surveys on effects of trawling is equally troubling from a balance perspective.

For a sample of the divergence of scientific opinion on the effects of trawling, consider the degree to which the conclusions embraced in the Auster and Langton (1999) paper, as embraced by the SEIS, differ from other studies. For instance, although the ICES (2000) literature survey is effectively treated as irrelevant by the SEIS authors, the work is considered by many scientists to be the most definitive evaluation of empirical studies on trawling to date. The finding in the ICES (2000) paper that most directly contradicts those embraced in the SEIS is the conclusion that there is no unequivocal scientific evidence that trawling does affect long term habitat complexity and bio-diversity. Many of the studies reviewed for the ICES (2000) paper were undertaken in areas in Europe that have been subjected to trawling effort similar to or greater than those in Alaska and with types of trawl gear that are thought to create more disturbance of substrates than otter trawls (Bergman and Santbrink 2000, Collie et al. 2000). Despite this, the ICES (2000) paper, in fact, concluded that although some aspects of fish habitat can be modified by trawling in areas where intensive fishing occurs, the effects of natural disturbance on changes in the relative abundance and species composition are at least as important a factor in determining changes of benthic communities as fishing gear effects. By dismissing this rather different conclusion, the SEIS analysis appears to arbitrarily minimize an important area of scientific dispute.

The main reason provided in the SEIS for minimization and dismissal of the ICES (2000) paper’s conclusions is that the focus of the ICES (2000) paper is supposedly limited to reviewing studies of groundfish fisheries off Europe, which SEIS authors claim has a longer and more convoluted fishing history than that of Alaska. Another is that the SEIS authors claim that most of the papers reviewed for ICES (2000) are studies of beam trawl effects, while SEIS authors imply that most studies reviewed for Auster and Langton (1999) are of otter trawl effects. Lastly, the SEIS authors attempt to point out some similarities in the findings of the two works while minimizing the very different conclusions on effects on habitat complexity and bio-diversity, two areas where the SEIS’ baseline findings derive most of their later conclusions about the benefits of measures presented in habitat protection alternatives. It is instructive to evaluate the merits of the reasons offered by SEIS authors for endorsing the views of the Auster and Langton (1999) review while dismissing the ICES (2000) review.

The first issue is how the relevance of the ICES (2000) paper or the Auster and Langton (1999) paper is affected by the types of trawl gear considered in the two literature reviews. The SEIS states that many of the studies reviewed in the ICES (2000) paper were studies of beam trawl effects rather than otter trawls, the gear predominantly used off Alaska. While this is true, the same is essentially the case for the Auster and Langton (1999) paper. In fact, all but a few of the trawl studies reviewed for the Auster and Langton (1999) paper are studies on beam trawl effects. Further, the Auster and Langton (1999) review also includes studies of clam dredge effects. The relevance of studies on clam dredge gear should probably be discounted because that gear is designed to achieve greater penetration of substrates than trawls in general.

So the underlying issue for both the ICES (2000) and the Auster and Langton (1999) papers is whether beam trawl studies are applicable or at least valuable in assessing the effects of otter trawls. Beam trawl effects are recognized to be more severe than otter trawl effects because beam trawls use heavy, rigid beams to spread the net and keep it on the ocean floor while otter trawls, like those used off Alaska, employ tow nets with footropes equipped with discs or rollers. Otter trawls use floatation on the headrope and other areas of the trawl to compensate for much of the displaced weight of the footrope gear, and in some cases achieve close to neutral buoyancy. So studies of beam trawl effects are probably only useful in determining an upper bound for disturbance of substrates and otter trawl effects fall well below that bound (Bergman and Santbrink 2000).

The preponderance of empirical studies of trawl effects worldwide have focused on beam trawls and all literature reviews have to take advantage of the literature available. The Auster and Langton (1999) review does include a few papers on otter trawl effects, but some of those are studies of trawling in Australia, New Zealand, and other sub-tropical countries where sediment types are vastly different, coral and invertebrate species are different, depths at which the fisheries are conducted are grossly different, and ambient degrees of natural disturbance are likely dissimilar. Thus, the tradeoff between a beam-trawl focus (ICES 2000) and a beam-trawl focus with some otter trawl and clam dredge studies included (Auster and Langton 1999) is hardly straight forward because the latter paper’s inclusion of studies of fishing effects in southern latitudes may be less applicable than studies of similar groundfish fisheries off Europe. Furthermore, dredge effects are probably least applicable to otter trawl effects. Contrary to the assertion made in the SEIS, there is certainly no clear-cut reason why the studies covered by Auster and Langton (1999) are more applicable to the gear used for trawling off Alaska.

The claim that the purportedly longer fishing history off Europe is a reason to dismiss the ICES (2000) paper is equally misguided. The Japanese started large-scale industrial “steam” trawling off Alaska in the 1950s, about the same time such operations started off Europe. Given that the SEIS habitat section finds that the effects of fishing with gears other than motorized trawls are probably negligible, the SEIS authors should have found that Alaska and Europe have comparable fishing histories.

From a scientific balance perspective, it is troubling that the ICES (2000) literature survey paper and other literature surveys that have conclusions different from the Auster and Langton (1999) survey are dismissed as irrelevant yet, the Auster and Langton (1999) paper is accepted as gospel.

A programmatic analysis should necessarily be broad in its scope and treatment of scientific information. Yet it is well known that the views and conclusions of the Auster and Langton (1999) paper are not widely accepted or replicated by other scientists. In fact, three of the long term effects studies reviewed by Auster and Langton (1999) to prove their thesis of indisputable negative effects of trawling (Reise 1982, Riesen and Reise 1982, and Holme 1983) were reviewed by Hall (1999) who found that the observed changes reported in each of these studies could not be attributed to fishing effects.

For a more detailed assessment of the Auster and Langton (1999) paper, we are attaching by reference an appendix attached to the Marine Conservation Alliance’s (MCA) SEIS comments submitted by Dr. Franz Mueter of Simon Fraser University. Those comments critique the use of the Auster and Langton (1999) paper vis-a-vis other available scientific papers and literature surveys on the effects of trawling. Dr. Mueter’s doctoral thesis at the University of Alaska, Fairbanks involved empirical analysis of demersal fish communities in the Gulf of Alaska and modeling analysis of potential linkages to environmental variables.

After carefully reviewing the Auster and Langton (1999) paper, its use in the draft SEIS, and a wealth of trawl impact studies and reviews (works reviewed in the Auster and Langton (1999) paper, studies that were not included in that review, and several studies that have been completed since the Auster and Langton (1999) paper was published), Dr. Mueter raises serious issues regarding the paper itself and its applicability to the trawl fisheries off Alaska. Dr. Mueter’s review concludes:

A review of the paper by Auster and Langton (1999) and of more recent literature on the impacts of trawling suggests that the paper is not an adequate summary of trawling impacts for evaluating potential benefits from management measures in Alternative 5 of the PSEIS. Auster and Langton (1999) reviewed a selected set of short-term studies that are not representative of the Bering Sea and Gulf of Alaska trawl fisheries, neither in terms of gear types reviewed, nor, most likely, in terms of the substrate on which trawling typically occurs. Therefore, the conclusion that a reduction of trawling in Alaskan waters and increased allocation of catches to fixed gear will have definite benefits in terms of increased habitat complexity and species diversity is not tenable. In addition, the shortcomings of some of the long-term studies cited in Auster and Langton (1999), suggest that there is little evidence for long-term effects even in some heavily fished areas. Therefore anticipated benefits from the management measures in Alternative 5 may not be as expected (the Mueter review as referenced above, page 24).

Another shortcoming to the SEIS analysis is that it attempts to corroborate the use of the Auster and Langton (1999) paper as a scientific baseline for the section by pointing to supposed similarities in that work to the findings from two empirical studies of trawl effects off Alaska. While this approach at first appears reasonable, the Alaska studies discussed in the SEIS are in no way efforts to discern the general effects of trawling off Alaska. For instance, the Freese et al. (1999) paper is a rather narrow “what if” study to evaluate experimentally the effects of trawling in extremely rough and rocky areas in the Eastern Gulf of Alaska (a study area that most in the industry feel is “un-trawlable”). The area has dense coral, sponge, and related invertebrate assemblages. Freese et al. (1999) is not a study of the effects of actual trawling practices in the fisheries in the Gulf of Alaska and there is ample evidence to show that the trawl fisheries off Alaska successfully avoid fishing such rough-bottom areas.

Regarding the other empirical work that the SEIS authors offer as corroborating evidence of confirmation of the Auster and Langton view of the world is a narrow study of differences in the species composition of trawled versus less-trawled or un-trawled areas over a fairly long period of time (McConnaughey et al. 2000). That paper is not in any way proof that trawling, as it is currently conducted off Alaska, reduces habitat complexity and benthic diversity. This is because although the paper concludes that there is a statistically significant difference in the number of some benthic organisms between the unfished control and fished treatment, this in no way establishes or attempts to establish any ecological importance of the apparent difference between the fished and unfished areas. In cases where some organisms are more abundant in the unfished or fished areas, the fact that there is a statistically significant difference in occurrence rate proves that we can tell that a statistically significant difference exists, not that the difference (the difference is small in most cases) means that habitat function or diversity is really any different between the two areas.

Section’s conclusions that bottom trawling in general necessarily reduces habitat complexity and benthic biodiversity amount to an artifact of the decision to adhere to the Auster and Langton (1999) paper’s opinion of trawl effects. This is not the only, nor the most scientifically supportable conclusion. Further, we do not feel it is scientific to take two limited studies off Alaska to attempt to bolster the conclusions of the SEIS on the general effects of trawling. We feel this oversteps the significance of those two studies which were conducted in a fairly limited range of habitat types and areas, not to mention that the Gulf of Alaska study (Freese et al.1999) was not even attempting to look at long term effects.

Regarding the SEIS author’s general acceptance of the contention that trawling changes the species composition of benthic communities, there is additional scientific evidence that has come to light since the SEIS was written that does not support this conclusion. Several experimental studies employing careful controls have found that natural variability in benthic communities may exceed the effects of trawling (Lindegarth et al. 2000, Kenchington et al. 2001). These works have underscored the finding that benthic communities are inherently dynamic and undergo large fluctuations in abundance regardless of fishing effects.

Two points brought out in the baseline information presented in the section of bottom trawl effects are valid and important. We mention these because management alternatives could have been developed around these specific points. One is that trawl effects (and all effects of bottom-tending gear) vary by type of substrate, depth and degree of ambient natural disturbance, and type of gear used. This finding is common to virtually every scientific survey of effects of trawling and appears to be an important consideration for understanding the effects of trawling.

Secondly, the SEIS authors do point out that one possible explanation for the failure to observe habitat effects or downstream effects on fish habitat, in terms of effects to fish stocks off Alaska, may be due in part to the inherent resilience of habitat types in our area or possibly that there is a threshold of disturbance that must be obtained before effects are observable or obvious. While some have argued that the threshold is a cumulative amount of trawling, in sand and mud substrates characteristic of much of the area where groundfish trawling is conducted off Alaska, the more important threshold could be the amount and degree of disturbance to catch the TAC each year on a relevant spatial scale. In this sense the failure to “find” a habitat problem for the fisheries off Alaska may demonstrate that the amount and spatial distribution of trawling off Alaska may be below some threshold.

Ideally, the SEIS analysis could be a roadmap to evaluate the allowable fishing levels based on important determinants of effects and what is known about downstream consequences. To accomplish this, the analysis could map out how to use available information on the depth and type of substrate fished, gear type used, and other relevant information to evaluate and possibly estimate the amount of fishing or intensity of fishing that would be sustainable in a given area. In evaluating the data presented in the SEIS and potential alternative ways to structure alternatives for habitat protections, Dr. Mueter’s review explores this possibility and suggests:

Ultimately, it is more important to estimate effect sizes and use these to determine levels of fishing intensity for a given habitat that are sustainable. This requires estimates of the fine-scale distribution of fishing effort and knowledge of the distribution of benthic organisms. Alternatively, analyses of benthic community structure in relation to fishing effort combined with modeling can provide estimates of sustainable fishing rates (Pitcher et al. 2000), (Mueter review, page 24).

Sections 3.2.3 and 3.2.4

  • “Longline Gear” and “Pot Gear”

The section on longline gear would benefit from the inclusion of information available in NMFS’ AFSC Processed Report 98-01, which describes observations from a manned submersible as bottom longline gear is being retrieved in the Gulf of Alaska. This paper reports observations from a submersible of the effects of longline gear on invertebrate communities. As such, it is not a controlled empirical study, but provides some information nonetheless and is useful given the dearth of information on effects of fixed gears. Along with the evidence cited in the SEIS on effects of fixed gears, the above paper and other descriptive accounts from submersibles and dives in such regions as the southeast United States form the limited information available on the effects of longline and pot gear on EFH and especially emergent epifauna, such as standing invertebrates (corals, sea pens, sponges, etc.).


  • For Correcting the Deficiencies/Making Improvements to Sections 3.2.1 – 3.2.4 of the SEIS

In addition to the suggestions made in the comments on the above sections, we have a few additional major suggestions. The most important modification to the sections under Section 3.2 would be to adopt a more scientifically credible baseline for the effects of trawling for groundfish fisheries off Alaska. Our comments above and those made by Dr. Mueter should be addressed in the reconsideration of Section 3.2 and ultimately Alternative 5 measures. As currently written, the Section 3.2 baseline on gear effects does not reflect the best available data and use of scientific information. The SEIS’ adoption of the Auster and Langton (1999) paper’s conclusions and attempt to establish its relevance to fisheries off Alaska is simply not appropriate.

The analysis should also avoid attempting to corroborate the conclusions of the Auster and Langton (1999) paper, which we feel the scientific community as a whole views as an extreme view of trawl effects that is not very applicable to the trawl fishery off Alaska with a subset of conclusions from two narrowly-focussed empirical studies off Alaska.

Next the analysis should review what is known about trawling for groundfish off Alaska and other types of fishing gear including: the types of substrates fished, the intensity of fishing, the relative health of groundfish and other affected stocks, and other important factors such as the existing management protections for habitat and other management constraints that affect how fishing occurs (e.g. existing no-trawl areas and PSC caps). This information should be compared to the general scientific information about trawl effects to make inferences, in the absence of dedicated empirical studies off Alaska, regarding the likelihood that fishing in our region is affecting habitat negatively in terms of productivity and other relevant factors.

For an example of how this could be done, a recent analysis attempted to scale the available scientific information from a large bibliography of studies on fishing gear effects. Scaling was in terms of the characteristics of the fisheries and fishing gears and the effects that were detected in the different empirical studies (Collie et al. 2000). This approach would be a credible way for the SEIS to evaluate which habitat protection options appear warranted and what the expected benefits of habitat protections might be.

One very important final recommendation is that the assessment of effects of fishing gears in Section 3.2 should adequately consider what the range of possible fishing effects on habitat actually means in terms of productivity of fish stocks and the ecosystem. Section 3.2 and the analysis of Alternative 5 measures that follows barely touches on the fact that for Alaska, little is known about the significance of potential modifications to habitat. This admission so “late in the game” is more than slightly incongruous with the adoption of the Auster and Langton (1999) thesis that trawling unequivocally reduces habitat complexity and biodiversity, not to mention the conflict it creates for Alternative 5 measures that flow from that conclusion. The only mention that the there is no real evidence of a habitat effects problem for the groundfish fisheries off Alaska comes in Section 4.7 where the analysis states:

In conclusion, the linkage between fishing and habitat characteristics is not known with great precision for Alaskan fisheries. The absence of fish stocks below their minimum stock size thresholds (Section 4.4) implies that the status quo fishery has not had significant impacts on the productivity of stocks in the BSAI and GOA. (SEIS page 4.7-39).

The important admission that the linkage between habitat characteristics and fishery productivity is unknown should have been explicitly recognized from the outset. Often the notion of “effects” in the SEIS baseline is treated as if it were synonymous with the notion of threats to sustainability of the ecosystem off Alaska. This is evident in the SEIS’ treatment of some of the findings in the McConnaughey et al. (2000) paper where the SEIS section authors appear to believe that a statistically detectable effect, in terms of small positive and negative differences in occurrence of certain benthic organisms, is necessarily an indicator of loss of sustainability and importance of ecological function. We seriously doubt that many scientists, including the author of that study, would support the conclusion that the effects observed in the above referenced study are necessarily ecologically important or are unambiguous evidence of reductions in fishery productivity. That some sorts of changes associated with trawling can be detected in some cases and under certain conditions does not mean the changes are necessarily “big” or “bad” for the ecosystem.

Comments on Section 4.7.2

  • Impacts of Alternatives on Essential Fish Habitat

The introduction and preface sections of the SEIS suggest that the specific content of each alternative is not as important as the measures in the alternatives. The agency apparently recommends that we view the alternatives as examples of management regimes designed to create benefits addressing different types of possible management objectives recognizing that fishery management is more than just a singularly focused endeavor. Nonetheless, we have opted to provide comments on the specific measures in Alternative 5 for the purpose of evaluating the merits of each measure.

As is pointed out in the latter part of Section 4.7 of the SEIS, the absence of Alaskan groundfish stocks below their minimum stock size thresholds implies that the status quo fishery has not had significant impacts on the productivity of stocks in the BSAI and GOA. This means there is no real evidence of a problem with the current measures in place to protect EFH in the North Pacific. For this reason as well, we do not think that there is evidence of a need to further restrict any gear type currently being used in groundfish fisheries off Alaska. While it is undoubtedly true that all groundfish fishing somehow modifies benthic habitat and that some sorts of changes associated with fishing can be detected off Alaska, this does not mean the changes have been detrimental to ecosystem function or fishery productivity. In fact, the evidence off Alaska suggests that whatever effects on EFH that may have occurred are not harmful.

For the above reasons, we feel the introduction of new management measures when there is no evidence of a problem is not really advisable. This is of particular concern because the proposed Alternative 5 measures would not only have devastating economic consequences on the trawl sector, but could potentially compress fishing activities into a smaller area and a common finding of scientific studies on EFH effects has pointed out that fishing intensity has been associated with the nature and degree of observed effects. For all of the above reasons, we think there is sufficient evidence that Alternative 5 measures and the SEIS baseline in Section 3.2 are not reasonable and fail to meet the “to the extent practicable” criterion of the Magnuson Stevens Act mandate for measures to minimize impacts of fishing on EFH.

Despite our convictions regarding the merits of Alternative 5, we are compelled to make very specific comments on the alternative and its foundations because through the SEIS process we can hope to affect changes and improvements to the document which will become the basis against which any proposed new management measures will be compared. We hope that these comments will be useful in revamping this section of the SEIS so that unsupported conclusions will not be part of the foundation from which our fisheries will be managed. What follows is an evaluation of how the proposed measures in Alternative 5 compare to the evidence in the draft SEIS and outside information on the effects of fishing off Alaska.

One overarching feature of Alternative 5 is that the selection of measures intended to create benefits in terms of habitat protection is completely dependent on a wholesale acceptance of the baseline section on general effects of fishing gear (sections already discussed in our comments above. Specifically, most of the expected benefits of the alternative are dependent on the SEIS’ assertion that trawling reduces habitat complexity and bio-diversity; the Auster and Langton hypothesis.

To accomplish the habitat protection benefits purported to result from Alternative 5, specific measures include: 1) making Pacific cod and Greenland turbot fixed-gear only fisheries with the assumption that the TACs would be taken and that fixed gear would have less impact overall on EFH; 2) requiring that certain rockfish species be taken only with “pelagic trawls” and requiring other species of rockfish to be fixed gear only (assuming once again the catch would be taken and that there are habitat benefits to these actions); 3) reducing the area available for flatfish and Atka mackerel trawling and reductions in TAC for those species proportionate with the area closed; and 4) closure of all “fishing specified” HAPC areas as per the areas identified in NPFMC 2000 (HAPC plan amendment to reduce effects on gorgonian corals). We do not comment on this last measure because the specifics of the alternative are not provided in the draft SEIS.

Alternative 5 Measures

  • With Respect to Expected Habitat Protection Benefits

Alternative 5 sets out to evaluate and rank the benefits of the proposed measures in terms of “direct” and “indirect” effects of the measures on EFH relative to the current management regime. In many ways, the discussion of effects on habitat in Alternative 5 measures compared to the current management regime does not correspond to the expectations for habitat protection benefits described for Alternative 5.

First of all, the discussion of the differences in effects of fixed versus trawl gear is somewhat inconsistent with the conceptual discussion of effects in Section 3.2, the baseline section. While Section 3.2 and the description of the selection of potential measures to be included in Alternative 5, (Section leaves the reader with the impression that SEIS authors are certain that Alternative 5 measures were selected because they are the most likely to produce habitat protection benefits, and the promise that the benefits will be realized under Alternative 5 is greatly downplayed in the discussion of Alternative 5 measures in section 4.7.

For instance, Alternative 5 is based on an assumption that the reallocation of Pacific cod and other species to fixed gears will produce habitat benefits because fixed gear is thought to have smaller impacts on important types of EFH. Yet considerable ambiguity clouds this issue later on in Section 4.7 of the document. For example, page 4.7-13 states:

Longline and pot gear can damage HAPC biota by hooking, crushing and plowing. Pots and longline groundlines being retrieved from the bottom can sheer sessile organisms. Our assumption is that fixed gear has less impact on HAPC biota than mobile gear such as bottom trawls. However, in some cases, fixed gear may have a greater impact due to its ability to be more easily fished on a wider range of habitat types, such as rougher substrates, (e.g. boulders with coral) than mobile gear.

This new description departs from the baseline description in the gear effects section (Section 3.2), and describes fixed gear effects on HAPC biota that are effectively very similar to the SEIS’ description of what trawls can do in similar areas. This begs the question of the underlying rationale for the expected benefits of Alternative 5.

Another part of the analysis that further renders uncertain the expected habitat benefits of Alternative 5 are the tables that purport to score the alternatives relative to the current regime (Table 4.7-14). Alternative 5 receives a “+2″ for reduction of HAPC biota damage/removal by trawls, but a “-2″ for increase in damage/removal of HAPC biota by fixed gear. While the authors suggest that these ordinal rankings are not designed to measure the precise difference between benefits as they relate to different gear effects, the tables do underscore the notion that the benefits from a reduction in trawl impacts on HAPC biota are offset to some degree by the increase in habitat impacts on HAPC by the fixed gear sectors that would make up the catches reallocated to fixed gears.

We know from the text in Section 3.2 and parts of Section 4.7.2 that fixed gears are known to impact fragile sessile invertebrates and that comparative scientific studies of effects by different gears are not available. In the end, the analysis provides no scientific information to demonstrate that the redirection of the harvest of certain species to fixed gear will necessarily deliver the expected habitat benefits. Furthermore, portions of the text even suggest that fixed gears could be fished in more vulnerable substrates thus increasing impacts on those areas.

The same is true of the rankings of effects on non-living substrates. Table 4.7-14 ranks the reduction of impact by bottom trawls as a “+2″ and the increase in the modification of non-living substrates by fixed gear as a “-2″, and there is no metric provided to discern the net effects.

The piece of information that renders most doubtful the assumption of benefits to EFH from the measures proposed in Alternative 5 is the observer data on catch rates of HAPC biota per ton of target catch, as reported in Tables 4.7-4 4.6-7. These tables detail the catch rate of selected HAPC biota of concern such as sponges, corals, sea whips, and anemones. It is interesting to note that the bycatch rates, based on the SEIS’ reported observer data from 1997-1999, is higher for several HAPC species for some fixed gears than for bottom trawls. Further, Table 4.7-6 and 4.7-7 extrapolate the catch rates for different gears and fisheries to the expected overall catch of HAPC biota under different SEIS alternatives. If one sums the overall catch of fragile HAPC biota for the current regime compared to what would be expected under the “habitat protection” regime under Alternative 5, one discovers that the expected habitat benefits from the alternative in terms of reduction of catch of HAPC biota are, in fact, rather dubious.

In the Gulf of Alaska, HAPC biota bycatch actually increases under Alternative 5 compared to Alternative 1, the status quo, and in the Bering Sea, a slight reduction in HAPC biota is predicted to occur.

Based on the information in section 4.6, to actually achieve a significant reduction in HAPC bycatch, a reduction in the catch of cod, sablefish, and other fish stocks would have to occur, or significant area closures for all bottom-tending gears would have to be implemented. Such measures would have been less allocation-driven, hence less divisive and controversial from a distribution of benefits and costs perspective.

Another vexing feature of Section 4.7 is that it reports and effectively admits that there is no scientific rationale for the alternative’s imbedded assumption that fixed gears harvest fish with less effect on EFH. Particularly, SEIS page 4.7-10 states that:

An important assumption here is that the adverse impacts to benthic habitat by bottom trawls are greater per unit of fish harvested than for fixed gear. This assumption is based on conventional knowledge, although it is recognized that comparative studies among different gear types have not been performed and that fixed gears (pots and longlines) or pelagic trawl gear that comes in contact with the seafloor can also disturb benthic EFH. However, most scientific studies of gear impacts have dealt with mobile gear such as beam trawls, otter trawls, and scallop dredges (Auster and Langton 1999, Jennings and Kaiser 1998, Hall 1999b) because these gears are recognized as having the greatest potential for contact and damage to the seafloor and associated biota.

The admission that Alternative 5’s expectation of habitat benefits from the reallocation of catches to fixed gears is grounded merely on “conventional knowledge” is troubling. Given that studies of comparative impacts of different gears have not been done, there is no reason to conclude that “conventional knowledge” as this suggests, is correct or meritorious. The issue once again begs the question of why the measures in Alternative 5 were selected as illustrative of a habitat protection alternative.

Another issue is the Alternative 5 basis for assuming that there are benefits from requiring certain rockfish species be harvested with mid-water trawls. Currently, there is no scientific data regarding the extent or degree of bottom contact associated with “mid-water” nets used for rockfish in the waters off Alaska. Despite this, Alternative 5 concludes there are benefits from a mid-water-only requirement for trawling for certain species of rockfish.

Some fishermen targeting rockfish in the Gulf of Alaska have reported success in catching rockfish with “hybrid trawl gear” where the trawl doors (otter boards) are designed to be fished off bottom. The lower portion of the trawl net is not protected with discs or rollers but it is often fished in “close proximity” to the ocean floor. It is our understanding that fishermen are employing such nets for rockfish in some areas to increase catches and, in some cases, to increase the average size of rockfish captured by the trawl. While this may produce benefits to fishermen and consumers, the assumed benefits to habitat incorporated into mid-water only fishing for rockfish in the SEIS Alternative 5 have never been demonstrated. Scientific data or studies on the degree to which such rockfish nets are fished in contact with the seafloor, or the comparative nature of their seafloor effects relative to bottom trawls are currently not available. This is another instance where measures in SEIS Alternative 5 lack an adequate scientific foundation and the purported benefits may not be realized.

Additionally, this section should include a discussion of the areas where such rockfish trawl gear is currently being fished to evaluate whether the gear’s use is limited to a few areas or is widespread. If the gear is only feasible and effective in a small subset of areas, the SEIS should incorporate a discussion of the habitat and TAC considerations of conducting a “pelagic-only” rockfish fishery in a limited number of areas (here “areas” means certain gullies and pinnacles) compared to the current conduct of the fishery.

As our comments above demonstrate, the basis for virtually all of Alternative 5’s purported benefits is rather questionable and the alternative needs to be reworked. Before turning to our recommendations, one further comment is warranted. We can find no place in the SEIS where the practicality of the proposed measures in this alternative are rigorously and explicitly evaluated. Because the EFH mandate of the Magnuson Stevens Act stipulates that impacts of fishing gear on EFH have to be minimized, to the extent practicable (our emphasis), it is appropriate to expect that the analysis evaluate the feasibility and practicality of the measures.

From our perspective, there is little doubt the proposed suite of measures under Alternative 5 would devastate trawlers who depend on cod, flatfish, Atka mackerel, and species of rockfish that the alternative would allocate to fixed gear. For instance, H&G vessels and catcher vessels that concentrate on those species for part of their annual revenues would face a cumulative loss of revenue from the prohibition on cod and turbot trawling, the reduction in Atka mackerel TAC, and the loss of valuable rockfish species like shortraker and thornyhead, of as much as one-third to one-half of the total annual revenues. Additionally, this would compress trawl fishing and processing capital onto a smaller revenue base and further erode returns to the non-pollock trawl sector that operates on close margins right now. Further, with the reduction of fishing areas for flatfish, the ability of the fleet to find areas to fish flatfish with low bycatch rates could reduce or impair our ability to make up forfeited revenues from the other measures. Lastly, the effects of the HAPC protection fishing area restrictions could further reduce fishing opportunities, but without any specific information about the areas that would be closed, we cannot estimate the additional impacts of the HAPC measures at this time.

At the same time, part of the issue of what is “practicable” involves the notion of whether other sectors would make up the revenues forfeited by the trawl sector, or if the result would be unrecoverable losses to the industry and society in terms of consumer and producer net benefits. While we cannot know with certainty to what degree the catches would be made up by other fishermen, we feel the analysis should have explored this issue.

Given that longline gear is the predominant fixed gear for Pacific cod and the only existing alternative gear for turbot, the analysis should consider the potential constraints affecting the harvest of additional cod and turbot by that gear. Specifically, longlining for cod is currently governed by a cap on the incidental take of short-tailed albatross, an endangered species. The incidental capture of two short-tailed albatross over the period of two years would be expected to result in measures that would greatly affect the longline fishery for cod, possibly resulting in its closure. Even if the capture of albatross is thought to be a random event and the probability is not affected by the amount of cod available to the longline fishery, it still remains possible if the measures in Alternative 5 were implemented, that the longline fishery for cod could be closed due to the albatross bycatch cap. This would likely result in impacts to the trawl industry that far exceed what would be considered to be “practicable” and would also result in unrecoverable lost benefits from the fisheries as a whole.

Other potential reasons why catches might not be made up by the fixed gear sector is that halibut is a binding constraint on the longline sector and additional catch could extend the fishery into times of the year such as the summer when halibut bycatch rates are generally higher. Further, the ratio of turbot product produced per ton of turbot catch is lower for the longline turbot fishery than for the trawl fishery, even if the two are making the same H&G products. This occurs because a significant portion of the longline catch is lost to killer whales that often follow the longline vessels to consume turbot as the longline is retrieved. When there is evidence of predation of fish on the longline, this catch still counts against the TAC and the resulting loss can be so large at times that many longliners actually abandon turbot fishing even with the fishery still open.

These are the main potential constraints on the fixed gear sector that could result in a net reduction in catch and loss of attendant economic and social benefits that are currently available from the fishery.

Recommendations for Modifications

  • To the Analysis of Alternative 5

In addition to the issues raised above, our strongest recommendation is that the SEIS Alternative 5 and Section 3.2 consider the points raised in the Mueter review and address the lack of scientific balance and problems associated with the applicability of the Auster and Langton (1999) paper to the fisheries and fish habitat off Alaska. Addressing this issue will likely show that most of the presumed benefits of Alternative 5 that have to do with the reduction of bottom trawling are not necessarily scientifically justified or even likely to be realized.

Next, the presumption that reallocating trawl fisheries to fixed gears creates benefits in terms of habitat protections needs to be revised in accordance with the observer data on catch rates per ton of target species catch in the SEIS. Further, the SEIS contends that fixed gear effects of EFH are lower per unit of catch and bases most of this contention on “conventional thinking”. The SEIS admits that no comparative scientific studies are available to demonstrate. To reconcile this, at a minimum the SEIS Alternative 5 discussion of potential benefits from reallocation of catches to fixed gear should treat the potential for benefit as a possibility rather than an expectation that drives Alternative 5 itself.

The most troubling flaw imbedded in Alternative 5 is the way that potential effects of trawling or even those that have been observed under some conditions are treated as necessarily detrimental to the ecosystem or sustainable fisheries. The analysis should explicitly recognize the lack of scientific information on the linkage between potential or observed habitat effects off Alaska and ecosystem function and fisheries productivity. The discussion of expected Alternative 5 benefits would be a lot more credible if it admitted up front, rather than as an afterthought, that the absence of fish stocks below their minimum stock size thresholds implies that the status quo fishery has not had significant impacts on the productivity of stocks in the BSAI and GOA.

In this regard, one of the most pressing needs of the draft SEIS Alternative 5 section is to apply the notion of precaution in a more even-handed manner, instead of applying precaution in the case of measures to manage trawl effects alone. As the document points out, there is little known about fixed gear effects. Further, a balanced treatment of the issue of trawl effects off Alaska will likely conclude that we do not know with certainty the effects of trawling off Alaska. In consideration of the healthy state of groundfish stocks, there is no compelling evidence that any further restrictions on current fishing practices are warranted at this time. Until a better scientific foundation is available, Alternative 5 should incorporate a more even-handed standard for precaution to evaluate effects of all options and all fishing gears. Such a standard promotes fairness and is the most scientifically defensible course of action.

For the reasons above, we think that Alternative 1 is preferable to Alternative 5. We maintain that there is no problem with habitat protections in place for the groundfish fisheries off Alaska and that groundfish stocks are healthy. The current management regime has never hesitated to develop restrictions on fishing gears when the expected benefits are demonstrable and sound. A balanced approach to the available scientific information does not support most of the measures in Alternative 5 and better supports the status quo management for groundfish.

Literature Cited

  • Auster, P. J., and R. W. Langton. 1999. The effects of fishing on fish habitat. American Fisheries Society Symposium 22:150-187.
  • Auster, P.J., R.J. Malatesta, R.W. Langton, L. Watling, P.C. Valentine, C.L.S. Donaldson, E.W. Langton, A.N. Shepard, and I.G. Babb. 1996. The impacts of mobile fishing gear on seafloor habitats in the Gulf of Maine (Northwest Atlantic): implications for conservation of fish populations. Reviews in Fisheries Science. Vol. 4(2):185-202.
  • Bergman, M. J. N., and J. W. V. Santbrink. 2000. Mortality in megafaunal benthic populations caused by trawl fisheries on the Dutch continental shelf in the North Sea in 1994. ICES Journal of Marine Science 57:1321-1331.
  • Collie, J. S., S. J. Hall, M. J. Kaiser, and I. R. Poiner. 2000. A quantitative analysis of fishing impacts on shelf-sea benthos. Journal of Animal Ecology 69:785-798.
  • Freese, L., P. J. Auster, J. Heifetz, and B. L. Wing. 1999. Effects of trawling on seafloor habitat and associated invertebrate taxa in the Gulf of Alaska. Marine Ecology Progress Series 182:119-126.
  • Hall, S. J. 1999. The effects of fishing on marine ecosystems and communities. Blackwell Science, Oxford, UK.
    Holme, N. A. 1983. Fluctuations in the benthos of the western English Channel. Oceanologica Acta XX:121-124.
  • Hutchings, P. 1990 . Review of the effects of trawling on macrobenthic epifaunal communities. Australian Journal of Marine and Freshwater Research. Vol. 41:111-120.
  • International Council for the Exploration of the Sea. 1988. Report of the study group on the effects of bottom trawling. CM 1988/B, International Council for the Exploration of the Sea. p. 56.
  • International Council for the Exploration of the Sea. 2000. Effects of different types of fisheries on North Sea and Irish Sea benthic ecosystems: Review of the Impact II report. Report of the ICES Adv. Comm. on the Mar. Env. to the E.C. Dir.-Gen., Fisher, CM 1988/B, International Council for the Exploration of the Sea. p. 56.
  • Kenchington, E. L. R., J. Prena, K. D. Gilkinson, D. C. G. Jr., K. MacIsaac, C. Bourbonnais, P. J. Schwinghamer, T. W. Rowell, D. L. McKeown, and W. P. Vass. 2001. Effects of experimental otter trawling on the macrofauna of a sandy bottom ecosystem on the Grand Banks of Newfoundland. Canadian Journal of Fisheries and Aquatic Sciences 58:1043-1057.
  • Lindegarth, M., D. Valentinsson, M. Hansson, and M. Ulmestrand. 2000. Interpreting large-scale experiments of effects of trawling on benthic fauna: an empirical test of the potential effects of spatial confounding in experiments without replicated control and trawled areas. Journal of Experimental Marine Biology and Ecology 245:155-169.
  • McConnaughey, R. A., K. L. Mier, and C. B. Dew. 2000. An examination of chronic trawling effects on soft-bottom benthos of the eastern Bering Sea. ICES Journal of Marine Science 57:1377-1388.
  • Megrey, B.A., and Wespestad, V.G. 1990. Alaskan groundfish resources: 10 years of management under the Magnuson Fishery Conservation and Management Act. North American Journal of Fisheries Management 10(2), pp. 125-142.
  • Messieh, S.N., Rowell, T.W., Peer, D.L., and Cranford, P.J. 1991. “The effects of trawling, dredging and ocean dumping on eastern Canadian continental shelf seabed.” Continental Shelf Research, 11, pp. 1237-1263.
  • Piet, G. J., A. D. Rijnsdorp, M. J. N. Bergman, J. W. v. Santbrink, J. Craeymeersch, and J. Buijs. 2000. A quantitative evaluation of the impact of beam trawling on benthic fauna in the southern North Sea. ICES Journal of Marine Science 57:1332-1339.
  • Pitcher, C. R., I. R. Poiner, B. J. Hill, and C. Y. Burridge. 2000. Implications of the effects of trawling on sessile megazoobenthos on a tropical shelf in northeastern Australia. ICES Journal of Marine Science 57:1359-1368.
  • Reise, K. 1982. Long-term changes in the macrobenthic invertebrate fauna of the Wadden Sea: are polychaetes about to take over? Netherlands Journal of Sea Research 16:29-36.
  • Riesen, W., and K. Reise. 1982. Macrobenthos of the subtidal Wadden Sea: revisited after 55 years. Helgoländer Meeresuntersuchungen 35:409-423.
  • Rijnsdorp, A. D., A. M. Buys, F. Storbeck, and E. G. Visser. 1998. Micro-scale distribution of beam trawl effort in the southern North Sea between 1993 and 1996 in relation to the trawling frequency of the sea bed and the impact on benthic organisms. ICES Journal of Marine Science 55:403-419.