March 2, 2001
Mr. Louis Chiarella
Essential Fish Habitat Coordinator
National Marine Fisheries Service
1 Blackburn Drive
Gloucester, MA 01930
Dear Mr. Chiarella,
Thank you for the opportunity to comment on the Essential Fish Habitat components of
the Northeast Multispecies and Atlantic Sea Scallop Fishery Management Plans (FMP’s). These
comments represent my opinion. Firstly, I am somewhat puzzled by the Scoping Document
where the statement is made that the Scoping Document initiates the formal FMP/EIS
development process. I have attended over 47 meetings in the last two years that worked
towards, to one extent or another, development of a Scallop Amendment. Habitat issues were a
major concern during these meetings. Many alternatives were considered and analyzed that
would and did mitigate impacts by scallop fishing gear on habitat and the species complex using
that habitat. I think there needs to be a clarification by NMFS on what exactly is the process that
will be followed.
My primary concern with the existing EFH process is the presumption that observed
impacts on EFH are adverse thus requiring some sort of mitigation. While it may be considered
precautionary by some people to make such presumptions, in fact it can be, and has been, highly
destructive to the fisheries management process and counterproductive to the goal of protecting
EFH. I will focus my remarks on scallop dredging but in most instances these comments apply to
other mobile gears as well.
Scallop dredging is not a new fishing practice. Scallop dredging and other mobile gear
activities have been taking place on the Georges Bank fishing grounds for over 100 years. In
fact, other fishing activities that have the potential to disrupt ecosystems, by selective harvesting,
have been underway on these grounds for over 500 years. The over-harvest of Atlantic halibut by
hook fishermen in the last century is just one example. The removal of such a large biomass of
halibut from the Georges Bank ecosystem had to totally change the habitat/species complex from
what had previously existed. The current practice of the recreational charter boat hook fleet of
targeting “mother cod” may be the biggest threat to this species with resulting EFH impacts.
Fishing effort by hook gear for large cod has in all likelihood altered species composition and
abundance with possible adverse impacts to cod stocks, biodiversity, and other aspects of the
existing ecosystems.
The rush to judgement on what constitutes important EFH may have substantial negative
impacts on ecosystem management. For example, NMFS has designated the northern portion of
Groundfish Closed Area II (CAII) as an HAPC for cod with minimal scientific evidence. The
HAPC extends as far east as 67 00' (the Hague Line), north to 42 10', west to 67 15' and as far
south as 41 50'. This HAPC encompasses areas that have been important cod and scallop fishing
grounds for this century and possibly many previous centuries. In the last seventy years mobile
gear, otter trawls and scallop dredges, have been the dominant harvesting tools on these grounds.
The relatively recent reduction in cod abundance in no way implies that the existing fishing
practices have a substantial adverse effect on this particular EFH. The slow rebuilding of cod
stocks may have more to do with the loss of large spawners harvested by the new charter boat
hook fishery than lack of rocks for juveniles to hide under.
It is a relatively easy to make the argument that mobile gear impacts habitat in many
ways. It is also easy to document that virtually all habitats that man has routinely encountered
have been altered in some fashion and many values have been lost or gained. These issues are
beside the point. The fundamental question is that given an altered habitat, how do we best
achieve all the goals of fisheries management. At this point in time, management authorities are
not proposing an outright ban on mobile gear. There are many good reasons for this policy.
However, there is a willingness to limit mobile gear in certain areas for habitat considerations,
such as the HAPC for cod. This concept can be described as the ‘let the bottom grow back’
theory. On the surface this theory may seem to be a logical precautionary approach. One
significant consequence of closing an area to mobile gear is that it shifts the fishing activity to
other locations which may be more essential. Shifting effort to passive gears, hooks and gill nets,
capable of fishing hard bottom that mobile gear can not access, may be detrimental to cod
rebuilding efforts.
The Cod HAPC
The Amendment for Essential Fish Habitat establishing the cod HAPC references a
number of scientific documents to build the case for the designation. The stated objective of the
HAPC is to improve the survival of juvenile cod. The cod HAPC encompasses one of the most
important and traditional fishing grounds of the sea scallop fleet. Any regulatory attempt at
restricting mobile gear in this area has significant economic impact on the scallop fleet.
Moreover, the designation has shifted effort to more complex ecosystems. A closer examination
of the Council’s argument needs to be made.
Any regulatory action with such significant consequences must be based on sound
science and reliable information, not driven by research agendas and false public perceptions.
The use of selective science to present one side of an issue in a public document is wrong. My
fear is that the desire of habitat scientists to make use of a research opportunity has overly
impacted their analysis. I need to present a detailed examination of the issue, only using same
scientific references cited in the existing Amendment, to demonstrate my point about selective
science.
The EFH Amendment document states “Several sources document the importance of
gravel/cobble substrate to the survival of newly settled juvenile cod”. The document further
explains that a “A substrate of gravel or cobble allows sufficient space for newly settled
juvenile cod to find shelter and avoid predation” The underlining is added here for emphasis.
References for these statements are Lough et al, 1989; Valentine and Lough, 1991: Gotceitas and
Brown, 1993; Tupper and Boutilier, 1995; and Valentine and Schmuck, 1995.
The above analysis groups gravel and cobble habitat as having the same impact on
juvenile cod survival. The references utilized do not confirm this similarity. Gotceitas and Brown
(1993) conducted tests with juvenile cod on three substrates; sand, gravel-pebble, and cobble.
Their results were “With no apparent risk of predation, juvenile cod preferred sand or
gravel-pebble. When cobble was present, juveniles hid in the interstitial spaces of the substrate
in the presence of a predator. With no cobble present, juveniles showed no preference between
sand and gravel-pebble, and did not seek refuge from predation in association with these
substrates.” Their conclusion.... ”these results demonstrate that neither sand nor
gravel-pebble were viewed by cod as offering safety from predation.” Based on this reference
the EFH Amendment conclusion that gravel provides shelter for juvenile cod is not
supported.
The EFH Amendment also uses Tupper and Boutilier (1995) to connect gravel and
cobble together. Their study found that cod survival was highest on rocky reefs and cobble
bottoms. Their study looked at four substrate types; sand, seagrass, cobble, and rocky reef.
There was no gravel substrate identified in their study. This reference thus does not
support the conclusion about gravel substrate.
Lough et al. (1989) hypothesize that the gravel habitat favors juvenile cod survival
through predator avoidance. There is no proof of this hypothesis or as stated by Gotceitas and
Brown (1993) “In their study, Lough et al. (1989) attribute the distribution of juvenile cod
among substrate types to a response by the juveniles to reduce the risk of predation, but no
direct evidence for this interpretation was provided.” In fact Lough et al. (1989) report one of
the two concentrations of juveniles found in late July 1987 as being in an area of varied bottom
types which does not confirm their hypothesis. This study is far from documenting the
importance of gravel substrate as stated in the Amendment document. Trawl studies identified by
Lough et al did find juveniles on sand bottom during August. The more logical explanation for
their observations is that on gravel substrates juvenile fish are broadly dispersed and easier to
find while over sand bottom the juveniles are tightly schooled and thus hard to find. Schooling
over sand bottom may in fact offer more protection from predation.
Valentine and Lough (1991) do not provide any documentation of the importance of
gravel substrate for juvenile cod survival. In fact, their study ends with a series of unanswered
questions one of which is “Do untrawled areas of the bank, especially the gravel habitat, serve
as refuges for juveniles and breeding adults that are important in sustaining a heavily utilized
fishery.” A good question, but certainly not documentation!
The Amendment document tries to establish that there is an ecological bottleneck due to
the fact that there is high predation on juvenile cod, but offers no references documenting the
existence of this bottleneck. They Cod HAPC meets the first classification criteria (i) as it
provides suitable habitat. The references show that in all likelihood it is the cobble and boulder
bottom that provides protection from predation. Lough et al. (1989) speculate that the gravel
substrate may provide a background that “ softens fish silhouettes and obscures movement that
predators cue on.” Fishing activity does not alter this background but may in fact enhance the
mottled backdrop. As stated by Lough et al. (1989) “The dredging and trawling activity may
help create the gravel seabed by mixing the sediment and allowing the gravel to migrate upward
through finer sediment to become concentrated at the surface.” Auster et al (1996) confirm
this observation on Jeffreys Bank; that after fishing “...much of the thin mud veneer was
missing, exposing more of the gravel base..”
There is an important management reason to differentiate between gravel bottom and
cobble/boulder bottom. Fishermen, especially scallop fishermen, do not want to tow on
cobble/boulder bottom. This is confirmed by the observations made by Valentine and Lough
(1991). The commercial scallop concentrations that the fishermen prefer to harvest on the
northern portion of the bank are on gravel and gravel/sand. There is no indication that fishing
disrupts this bottom at the expense of juvenile cod survival based on the references used to
establish criteria (i).
The EFH Amendment document goes on to state that “Specific areas on the northern
edge of Georges bank have been extensively studied and identified as important areas for the
survival of juvenile cod. These studies provide reliable information on the location of the areas
most important to juvenile cod and the type of substrate found in those areas.” References used
for this statement are Lough et al., 1989; Valentine and Lough, 1991; and Valentine and
Schmuck, 1995. It is important to not that for the most part these studies did not take place in
the Cod HAPC but were in fact to the east in Canadian waters (Lough et al., 1989). These
Canadian waters have virtually all the patches of cobble and boulder when compared to
US waters (Valentine and Lough, 1991). It is my contention that it is these cobbles and
boulders that make those sections of the gravel pavement important to survival of juvenile cod.
The remaining portion of the argument for the establishment of the cod HAPC is built
around the observation that scallop dredging “...reduces habitat complexity and removes much of
the emergent epifauna.” The EFH document then implies that scalloping activity, by reducing the
emergent epifauna, impacts juvenile cod “...survivability and readily available prey.” Again, the
document’s own references do not all support this argument. Specifically, Gotceitas and Brown
(1993) report that for offshore ecosystems typical of our region “...habitats characterized by the
presence of upright forms of vegetation are rare, and variation in habitat complexity is primarily
related to the size and composition of the mineral substrates present.” While bryozoans and
hydroids are not vegetation, the similar attribute of vertical height is what the document is
implying as being the important parameter. Collie (1998) refers to these animals as being
“plant-like”.
Tupper and Boutilier (1995) reported that newly settled cod “...were not closely
associated with vegetation, but sought refuge within the interstices of rocks, shells, and other
hard bottom.” In discussing the importance of habitat complexity on survival they indicate that
complex habitats may have very high predator densities resulting in higher predation mortality
compared to less complex habitats. Less complex habitats in temperate climates may produce
“...fewer, larger recruits, each with a relatively high chance of survival.”
Complexity in temperate marine systems is provided by water masses, such as cold water
upwelling or warm core rings. This is different than tropical marine systems where bottom
topography plays a key role. In the tropical marine systems reefs are considered “live bottom”
and
the sand areas between them are considered “dead bottom”. Yet, in temperate marine systems,
the flat relatively featureless sand/gravel substrates produce tens of millions of metric tons of
commercial harvest annually. The EFH document is overly concerned with substrate
characteristics and virtually ignores all other oceanographic features.
The EFH document has not explored all the options for habitat management. In the long
term the scallop industry would benefit by controlling where the scallops set and how to most
appropriately harvest the crop. In the meantime, some of our most important production areas are
of mixed substrate; gravel bottom with patches of cobble and boulder. There is a need to
examine alternative gear, i.e. lightly constructed dredges, as a means to protect habitat in mixed
substrate scallop production areas. Dredges of this design would be capable of being towed on
flat sand/gravel substrates but would have a high risk of being lost on cobble or rock strewn
areas. This alternative will eliminate large fishing area closures to protect small areas of critical
habitat and is highly enforceable. However, this approach is not currently available for
implementation.
The EFH components of the existing FMP’s suggest that newly settled juvenile fish have
increased chances of survival on complex seafloor habitat. If this is the case, there is more than
one management option. The one most advocated by preservationists is to close such grounds to
fishing, ie, non-extractive reserves. But why is there increased survival? Is it shelter from
predators? Food availability? If this is the case then an alternative would be to create more
shelter (ie, artificial reefs) and harvest predators; weed and feed. A related alternative would be
to increase and enhance the growth of dense epifauna and related communities by active
intervention (ie, seeding). These are certainly alternatives that should be considered by NMFS.
Two other points are important to keep in mind. One is that the number of predators in an
area is important on assessing juvenile survival. Secondly, hard bottom boulders may act as fish
aggregation devices (FAD’s) attracting large schools of predators to the vicinity. Hard bottom,
similar to some artificial reefs might not increase abundance; just aggregate it.
The most tried and true method for reducing fishery impacts is to increase catch per unit
effort. In the scallop fishery this can be accomplished by a rotational area management strategy.
The Nantucket Lightship Closed Area scallop fishery under scallop Amendment 13 is a fine
example of what can be achieved. Failure of NMFS and the NEFMC to reopen the Georges
Bank Groundfish Closed areas to a limited access scallop program, similar to the
Amendment 13 program, has been detrimental to achieving EFH objectives. The best action
NMFS can take to minimize effects (possibly adverse) of scallop fishing activities is to open
areas of dense scallop concentrations.
Sincerely,
Ronald Smolowitz
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megafauna of Georges Bank. Mar. Eco. Prog. Ser. 155: 159-172.
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Bank: photographic evaluation of effects on benthic epifauna. ICES C.M. 1996.
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