Spiny dogfish pupping in the St. Pierre Bank
Potentially Harmful Activity (X)
Fishing
Other
harvest
Seabed
alteration
Coastal
alteration
Disturbance
Bottom trawl
Scallop dredges
Clam dredges
Midwater trawl
Gillnets (bottom)
Gillnets (pelagic)
Longline
Seine (pelagic)
Recreational cod fishery
Crab pots
Lobster pots
Whelk pots
Other (specify)
Potentially Harmful Stressor (X)
X
X
Marine
pollution
X
X
Oil pollution
Industrial effluent
Fishplant effluent
Sewage
Historic military waste
Long range transport of nutrients
Acid rain
Persistent Organic Pollutants
(
)
Eutrophication
Ghost nets
Litter
Other contaminants (specify)
Ice distribution
X
Otter trapping
Seal hunt
Seabird hunt
Seaweed harvest
Anchor drops/drags
Ore spill
Fish offal dumping
Finfish aquaculture
Dredge spoil dumping
Dredging
Climate
Change
Temperature change
Sea-level rise
Ocean acidification
Current shifts
Increased storm events
Increased UV light
Oxygen depletion
Changes in freshwater runoff
Other :
Green crab
Mining/Oil & gas drilling
Cables
Freshwater diversion
Subtidal construction
Intertidal/coastal
construction
Harmful
species
Membranipora
Golden Star Tunicate
Violet Tunicate
Vase Tunicate
Codium fragile
Clubbed Tunicate
Didemnum
Harmful Algal Blooms
Disease organisms (human waste)
Disease organisms (aquaculture)
Other (specify)
Other (specify)
Vessel traffic
Ship strikes
Ecotourism
Marine construction
Seismic surveys
Navy sonar
Other (specify)
X
X
X
X
Other
1
Background Information
Distribution:
The spiny dogfish is a widely distributed boreal to warm temperate species distributed
over continental and insular shelves and upper slopes of the Pacific and Atlantic oceans
(Kulka, 2006). Their western Atlantic distribution ranges from Labrador to Florida, with
their centre of abundance located between the southern Scotian Shelf and Cap Hatteras
(Atlantic States Marine Fisheries Commission, 2002).
Sexually mature and pregnant females were distributed throughout the waters of
southwest Nova Scotia and the Bay of Fundy during the summer and fall, but moved
offshore to deeper waters in the winter. Females of mature size have also been observed
in the southern Gulf of St Lawrence and off southern Newfoundland (Campana et al.,
2007).
Figure 1. Distribution of female spiny dogfish of mature size (FL>73 cm) in summer
research surveys from 1971 – 2004 (Campana et al., 2007).
Spiny dogfish concentrate at bottom depths of 10 to 200 m in water ranging between 7°C
to 15°C. Thus, the spiny dogfish are at the northern limit of their distribution in
Newfoundland and Labrador waters. Spiny dogfish concentrate on the Western portion of
the St. Pierre Bank adjacent to the Laurentian Channel and onto the Hermitage Channel
(which has the highest Grand Banks bottom temperatures), in water depths of 100 to 250
m. They congregate in the warmest available water (>5°C) and the population are
comprised of mature adults. This suggests that St. Pierre Bank is a winter ground for
spiny dogfish (Jacques Whitford, 2007; Kulka, 2006).
2
Figure 2. Distribution of spiny dogfish on the Grand Banks, kg per tow 1971-2005
Canadian spring trawl survey (Kulka, 2006).
Temperature:
The largest catch rates and the greatest proportion of sets with spiny dogfish were
associated with 6-10°C, which effectively restricts their distribution primarily to the
western extent of the St. Pierre Bank where sufficiently warm thermal conditions exist.
This temperature preference helps to explain the consistently limited distribution of
dogfish on the Grand Banks (Kulka, 2006).
Duration:
In Newfoundland waters, spiny dogfish aggregations appear on St. Pierre Bank in June
then move into the south coast bays. Greatest concentrations are found in Placenta, St.
Mary's and Fortune bays. By late autumn (mid-October to mid-November) most of the
migrants have left Canadian waters on their return south. Evidence suggests however,
that numbers of immature males and females, as well as some mature males, may winter
in Newfoundland waters in deep channels and holes on St. Pierre Bank, in the Laurentian
Channel, and in some of Newfoundland's south coast bays (Marine Institute, 1993).
Spiny dogfish are observed on St. Pierre Bank during all months, also moving inshore
around Newfoundland in the summer months. Thus, at least some portion of the
population does not migrate south in the winter (Kulka, 2006).
Biology:
Spiny dogfish are small, migratory schooling sharks (Jacques Whitford, 2003). Spiny
dogfish have many characteristics of a metapopulation, whereby some dogfish
aggregations colonize or depart Canadian waters en masse at periodic multi-year
intervals, and then remain resident in those waters for many years at a time. The
existence of a metapopulation would imply that managing northwest Atlantic dogfish as a
single, well-mixed stock would be inappropriate. The Canadian dogfish cannot be viewed
in isolation. It is possible that a fishery on mature females in either Canadian or U.S.
waters could impact the abundance in all areas (Campana et al., 2007).
All evidence indicates that the mating and birthing of spiny dogfish takes place in the
winter months off the south-east coast of the United States. During the breeding season,
sexually mature dogfish form large schools (Marine Institute, 1993). To date, there has
3
been no evidence that migration is associated with a particular sex or size of dogfish
(Campana et al., 2007).
Spiny dogfish are ovoviviparous, with the young feeding and growing off a yolk sac in
utero before being born alive. This reproductive cycle takes 22-24 months, making it one
of the longest gestation periods known for any vertebrate (Campana et al., 2007).
Sexually dimorphic growth in spiny dogfish is strongly apparent. Females attain a greater
size than males, reaching maximum lengths up to 49 inches (125 cm) and weights up to
22 lbs (10kg)(Atlantic States Marine Fisheries Commission, 2002).
Prey/Predators:
The diet of this species is highly varied as these are opportunistic predators (Kulka,
2006). In the waters off Newfoundland, they feed mainly on small fishes including
capelin, herring, and Atlantic cod. They have few natural predators. Predaceous bony
fishes and sharks prey upon the newly born (Jacques Whitford, 2003).
Atlantic herring, Atlantic mackerel, and Loligo and Illex squid are important components
of the diet of spiny dogfish when they are abundant and available. Jensen (1965)
identified sharks (mackerel, great white, tiger, blue), barndoor skate, lancetfish, bluefin
tuna, tilefish and goosefish as predators of spiny dogfish (Atlantic States Marine
Fisheries Commission, 2002).
Population Trend:
The average weight of spiny dogfish on the Grand Banks fluctuated without trend with
respect to bottom temperature and depth. This indicates that the larger juveniles and
adults were mixed (Kulka, 2006).
The apparent absence of younger juveniles and the large fluctuations in survey abundance
estimates from year to year both suggest that spiny dogfish on the Grand Banks do not
comprise an independent stock: early life history (pupping and young juveniles) occurs
elsewhere (Kulka, 2006).
It is not currently possible to estimate trends in mature female biomass for spiny dogfish
in Atlantic Canada. However, the most recent assessment of northwest Atlantic dogfish
by the USA noted that female spawning portion of the biomass has declined by about
75% since 1988 and recruitment estimates from 1997 to 2003 have been very low
(Bundy, 2003; Campana et al., 2007). Over the past ten years, the area occupied by spiny
dogfish on the Grand Banks has diminished. Canada is undertaking a five year research
program through a Joint Project agreement with industry to address some of the
uncertainties outline above (Kulka, 2006).
The 2003 IUCN Red List assessment designated spiny dogfish as “Near Threatened” on a
global basis. Populations in the Northwest Atlantic are currently assessed as
“Vulnerable”, based on past fisheries records, stock assessments, and continued
unsustainable exploitation (Fordham, 2004).
4
There is a good deal of uncertainty with regard to the status of the northwest Atlantic
population (Kulka, 2006).
Figure 3. Biomass estimates of Squalus acanthias pups, Northwest Atlantic (Fordham,
2004).
Management:
First harvested over 100 years ago, the spiny dogfish was initially utilized for the
production of lamp oil, machine lubricant and Vitamin A. Today, it is valued as a food
within a number of countries. Spiny dogfish have also been targeted as "nuisance" fish
within the commercial fishery (Government of Canada, 2007). Spiny dogfish are
considered a unit stock in the Northwest Atlantic Ocean (US and Canadian waters) and,
as such, represent an inter-jurisdictional stock. On April 3rd, 1998, National Marine
Fisheries Service declared spiny dogfish overfished. The U.S.A. now has an Interstate
Fisheries Management Plan for spiny dogfish. The current federal FMP is based on a
constant fishing mortality strategy that allows for low bycatch landings in the initial
stages with increased landings as the female portion of the stock rebuilds (Atlantic States
Marine Fisheries Commission, 2002).
The U.S. federal measures are inconsistent with Canadian restrictions for the same
Atlantic population and their effectiveness is regularly undermined by non-compliance of
U.S. states in state waters. There are no bilateral or international management measures
to protect Spiny dogfish, although the highly migratory nature of this species means that
collaborative management is essential for fisheries targeting shared stocks (Fordham,
2004; Germany, 2007).
Within fisheries regulations, the spiny dogfish is defined as a groundfish species and is
governed by the groundfish Integrated Fish Management Plan (Government of Canada,
2007). Canada began restricting dogfish catch in May of 2002, following a significant
increase in landings in years just prior. The government capped 2002 commercial
landings at 2500 tonnes for the fixed-gear groundfish sector off Nova Scotia and in the
Bay of Fundy, based on landings history at the time. In addition, bycatch caps for other
fisheries consistent with historical landings and an additional 700 tonnes for a
cooperative industry sampling program were granted. The Canadian government has
5
stated that the caps are aimed to limit exploitation while future sustainable catch levels
are investigated (Fordham, 2004).
Quotas to this point have not been based on scientific advice, and there are no restrictions
on discarding and bycatch in other fisheries. Quotas have been set at 2,500 tonnes since
2002 (Campana et al., 2007). On the Atlantic coast, about 2,400 tonnes of this species
were landed in 2005. They are usually harvested by longline, gillnet, or handlines and are
a common bycatch in the groundfish fishery (Government of Canada, 2007).
In 2003, an intensive 5-year research program on Canadian dogfish was initiated by the
Department of Fisheries and Oceans, conducted in cooperation with the dogfish fishing
industry through a Joint Project Agreement (JPA) (Campana et al., 2007).
Bycatch:
The vast majority of landings come from Nova Scotia. Summer is the principle time for
dogfish fishing. Canadian landings have averaged about 2500 tonnes annually since
2000, with the majority of that being directed catch by handline and longline, followed by
gillnets. The 2002 quota of 3200 tonnes was exceeded by 384 tonnes, but directed catches
in subsequent years have not exceeded the quota (Campana et al., 2007).
On average, 14 tonnes of spiny dogfish was taken annually as bycatch in Canadian St
Pierre Bank (Div. 3Ps) fisheries from 1998-2005 primarily in the cod gillnet fishery,
mixed halibut/monkfish/white hake gillnet and longline fisheries, the redfish trawl fishery
as well as in crab pots and scallop dredges (Kulka, 2006).
The largest bycatch was associated with the groundfish (otter trawl, longline and gillnet
gears) and otter trawl redfish fleets in 4X5Y, although all areas and most fleets reported
large dogfish bycatch at some times. Spiny dogfish are relatively hardy, so it is only
reasonable to assume that discard mortality is not 100% (Fordham, 2004). Unfortunately,
there are few available estimates for dogfish discarding mortality. Area 4X accounts for
most of the dogfish in Atlantic Canada (Campana et al., 2007), which is outside the
PBGB LOMA. Total discards have averaged 2,000-3,000 tonnes annually in recent years,
although discards of up to 10,000 tonnes were estimated for some years in the 1990s
(Government of Canada, 2007).
The spiny dogfish is migratory and usually strongly aggregated by age and sex, making it
easy for fishers to maintain catches despite stock depletion and to target the most
valuable part of the stock (large, pregnant females). Heavily exploited populations
become male biased with associated reduction in pup production (Campana et al., 2007).
6
Figure 4. Bycatch distribution of spiny dogfish by fishery between 2002 – 2006, observer
data (Campana et al., 2007)
Figure 5. Estimates of catches of dogfish in commercial fisheries occurring on the Grand
Banks, northeast Newfoundland and Labrador shelf (Kulka, 2006).
7
Figure 6. Total catch and discard mortality of spiny dogfish caught in Canadian waters
since 1986 (Government of Canada, 2007).
Table 1: Commercial bycatch of spiny dogfish and black dogfish in Canadian fisheries on
the Grand Banks, 1996 – 2005 (Kulka, 2006)
Table 2: Canadian spiny dogfish landings (mt) by province (Campana et al., 2007)
8
Scoping
Bottom trawl:
Trawls are long, wedge-shaped nets of synthetic webbing that narrow into a funnelshaped bag. The bottom trawl is dragged along the seafloor and kept open during a tow
with large, oval, metal plates (doors). Footropes are often rigged with heavy steel rollers
or chains to keep the net on the seafloor. Multi-year studies of the impacts of groundfish
trawling carried out in the Atlantic by DFO show short-term disruption of benthic
communities, including reductions in the biomass and diversity of benthic organisms.
Some previously fished seafloor habitats showed recovery within one to three years but
frequently trawled habitats remain in an altered state (Fisheries and Oceans Canada,
2006).
Atlantic cod, redfish, and skate are fished with bottom trawl in this EBSA. Bottom trawl
accounted for only 1% of total catch (by landings) for the period 1998-2007 in this
EBSA, averaging approximately 27 tonnes per year during that time. Spiny dogfish are
observed on St. Pierre Bank during all months, moving inshore around Newfoundland in
the summer months (Kulka, 2006). Aggregations of both sexes have been noted offshore
during spring. Trawling occurs in the EBSA in all months, however redfish and cod are
not fished until July 1 and June 1, respectively.
Spiny dogfish are a directed species in the USA, with otter trawl accounting for
approximately 20% of landings (around 30 million tonnes until 2001, with quotas set
around 4 million tonnes after 2001). However, for the most part, dogfish tagged in
Canadian waters have remained in Canadian waters, and those tagged in U.S. waters have
remained in U.S. waters, with limited movement (10-20%) between Canadian and U.S.
waters (Campana et al., 2007). Therefore, US trawl fisheries should not impact the
aggregation in St. Pierre Bank significantly. On average, only 14 tonnes are taken
annually as bycatch in Grand Banks fisheries. Spiny dogfish bycatch was reported in
redfish otter trawl 3LNOPs (19.5 tonnes from 1996 to 2005) (Kulka, 2006) however
redfish is not harvested in the St. Pierre Bank EBSA. Because otter trawl was only
responsible for 1% of catch in the EBSA, it is not considered a key stressor. Screened
out.
Scallop dredge:
Both Iceland scallop and sea scallops are harvested within this EBSA. The fishery is
conducted on a year-round basis. Commercial bycatch of spiny dogfish in Canadian
fisheries from 1996-2005 listed scallop dredge as a source of bycatch only in the year
2000, and this totaled just 5.9 tonnes (Kulka, 2006). Because scallop dredge is not a
significant source of bycatch, it is not expected to be a key stressor. Screened out.
Gillnet (bottom):
Gillnets are fixed gear, and consist of vertical walls of mesh, with mesh openings sized
such that target species in the desired size range are caught as they attempt to swim
through the webbing, entangling their gills. Bottom gillnets are secured in direct contact
with the seafloor by weights and have a high incidence of bycatch. Within the LOMA,
9
offshore license holders are limited to 40-500 nets that are 91m in length and are usually
joined together (Appendix A, Table 5). This amounts to a maximum of 45.5 km of net
per license holder.
Atlantic cod, skate/monkfish, white hake, and Greenland halibut are fished with bottom
gillnet (for some fisheries from mid May to the end of February), and spiny dogfish
bycatch occurs in all months of the year (Kulka, 2006). For the St. Pierre Bank EBSA,
gillnet was responsible for 33% of landings (by weight) over 1998-2007 (6,426 tonnes
total). Landings with gillnet ranged from a high of 1248 tonnes in 1998 to a low of 167
tonnes in 2001 (Appendix A, Table 19).
The directed fishery in the USA utilizes primarily gillnet (accounting for 70% of
landings). Nova Scotia has a directed fishery for the species, which is sometimes targeted
with gillnet (Campana et al., 2007). Kulka (2006) showed commercial bycatch of spiny
dogfish in gillnet fisheries does occur, with 38.9 tonnes of bycatch taken from Canadian
fisheries on the Grand Banks from 1996 to 2005. In 2005, 85% of spiny dogfish bycatch
came from cod 3Ps gillnet fishery; in 2004; 44% resulted from white hake 3LNOPs
gillnet fishery; in 2002 57% came from redfish 3LNOPs gillnet fishery (Kulka, 2006).
There are no restrictions on discarding and bycatch in other fisheries. This species is
particularly vulnerable to over-fishing because of its late maturity, low reproductive
capacity and longevity (Fordham, 2004). The spiny dogfish is migratory and usually
strongly aggregated by age and sex, making it easy for fishers to maintain catches despite
stock depletion and to target the most valuable part of the stock (large, pregnant females).
Heavily exploited populations become male biased with associated reduction in pup
production (Campana et al., 2007). The northwest Atlantic population is classified as
Vulnerable on the IUCN Red List. Screened in.
Longline:
Bottom longlines are fixed gear, and consist of a single mainline to which shorter lines,
armed with baited hooks, are attached (maximum of 6,000). Anchors attached to the
longline secure the gear to the ocean floor. White hake, Greenland halibut, and Atlantic
cod are harvested in 3Ps using longlines. All these fisheries open in May, with cod
closing in November, halibut in December and hake closing at the end of February. Over
the period 1998-2007, longline accounted for 2% of landings in this EBSA (Appendix A,
Table 19). Over the last five years on St. Pierre Bank, the annual average catch with
longline was 24 tonnes (Kulka, 2006).
Nova Scotia has a directed fishery for spiny dogfish using handline and longline, and
spiny dogfish in the St. Pierre Bank area may move into Gulf areas. On average, only 14 t
are taken annually as bycatch in Grand Banks fisheries (Kulka, 2006). Kulka (2006)
shows that from 1996 to 2005 on the Grand Banks, longline was only listed as a source of
spiny dogfish bycatch in 2002 (0.4 tonnes) and in 2000 (7.6 tonnes), and that bycatch was
taken from all of 3LNOPs, not just the St. Pierre Bank region. Longline comprised just
2% of landings in the St. Pierre Bank EBSA, and bycatch reports show that only 8 tonnes
10
of spiny dogfish were taken from 1996 to 2005, therefore this gear is not considered a
key stressor to the CO. Screened out.
Crab pots:
Although crab is a very important fishery in 3Ps and responsible for significant landings,
most of the important areas are to the east of the EBSA in 3Psf and 3Psh. Harvesting
locations are shown in the Human Use Atlas covering the years 2000 – 2003
(Government of Canada, 2007) and the Sydney Basin SEA covering 2003 – 2005
(Jacques Whitford, 2007)- both of which show that crab is mainly taken from the area
east of the Canada-France boundary.
Snow/queen crab harvested in this EBSA accounted for only 2% of landings (by weight
landed) from 1998-2007. Over the last five years, landings averaged 14 tonnes. The
fishery is open from April to August, which coincides with spring aggregations of spiny
dogfish. Kulka (2006) showed that crab pots in all of 3LNOPs were responsible for 49%
of spiny dogfish bycatch in 2003 (3.8 t) and 46% in 2001 (3.0 t). Although this gear type
can by a source of bycatch, it is a small fishery which occurs mainly outside the EBSA;
bycatch is low; and Campana et al. (2007) does not list crab pots as a source of
significant spiny dogfish landings. Screened out.
Vessel traffic:
The St. Pierre Bank EBSA have between 4800-12,299 total vessel transits in an average
year (Pelot & Wootton, 2004). This is considered ‘medium-low’ within the LOMA. The
Cabot Strait sees approximately 6,400 commercial vessel transits annually (Jacques
Whitford, 2007), many of which could pass through some portion of the EBSA.
Large aggregations of mature females occur in deep warm waters off the edge of the
continental shelf and in the deep basins of the central shelf throughout their range in the
winter. Spiny dogfish can be found throughout the water column but they are typically
found near the bottom, at depths between 10 and 250 m (Campana et al., 2007). Although
there is medium-low vessel traffic along southern Newfoundland, this species is usually
found near the bottom, and vessel traffic and ship strikes are not reported to be a
significant stressor to spiny dogfish pupping. Screened out.
Seismic surveys:
The St. Pierre Bank EBSA (as well as Laurentian Channel and Burgeo Bank) falls within
the Sydney Basin Offshore Area, but exploration licenses do not overlap with the St.
Pierre Bank EBSA. Spiny dogfish lack a swim bladder. Fish with a reduced or absent
swim bladder have low sensitivity to sound pressure (Cummings & Brandon, 2004).
Seismic exploration noise level can range from 216 dB for a small single airgun to 259
dB for arrays (Jacques Whitford, 2007). There are no specific studies for spiny dogfish
sensitivity, therefore it is difficult to ascertain the impact on aggregations. We have no
information on spiny dogfish communication in aggregations. Startle responses and
temporary changes in swimming direction and speed could be expected for most fish
species. The expected distance for fish to react to a typical peak source level of 250 to
255 dB is from 3 to 10 km, physical injury to fish is limited to tens of meters (Jacques
Whitford, 2007). Auditory damage starts at 180 dB, transient stunning at 192 dB and
11
internal injuries at 220 dB. This stressor may become a key stressor if an exploration
licence is approved for the area in the future. There are no exploration licences or parcels
delineated for ‘calls for bids’, which also implies that no seismic surveys will occur in the
near future. Screened out.
Oil pollution:
The major source of oil in this EBSA would be derived from vessel traffic along southern
Newfoundland, and those on route to the St. Lawrence, Nova Scotia, etc. Vessel traffic
density is considered in the ‘medium-low’ range in this EBSA (Pelot & Wootton, 2004).
Aggregations of spiny dogfish are found offshore in winter and spring, which is not a
time of peak vessel traffic. There is a possibility of an oil spill from tankers using this
route. One oil exploration licence exists near Laurentian Channel, but there is currently
no exploration taking place in the St. Pierre Bank EBSA. There is potential for licences in
the future because the EBSA is encompassed by the Sydney Basin Offshore Area. Oil
pollution from vessel traffic is not considered a stressor to spiny dogfish pupping.
Screened out.
Temperature change:
Drinkwater (UNEP & UNFCCC, 2002) predicts a temperature increase of 2-4oC in
Southern Newfoundland waters by 2100, based on IPCC 2001 models. This rise will
likely not be linear, but is expected to accelerate over time. Even given the worst case
scenario, an increase in 0.4oC is all we can expect over the next ten years. This predicted
rise in temperature may be balanced by a potential drop in temperature resulting from a
reduced flow of the warm Gulf Stream Current and increased flow from the Labrador
Currents as a result of increased ice melt.
Spiny dogfish are at the northern limit of their distribution in Newfoundland and
Labrador waters. Spiny dogfish concentrate on the Western portion of the St. Pierre Bank
adjacent to the Laurentian Channel and onto the Hermitage Channel in the warmest
available water (>5°C). The largest catch rates and the greatest proportion of sets with
spiny dogfish were associated with 6-10°C, which effectively restricts their distribution
primarily to the western extent of the St. Pierre Bank where sufficiently warm thermal
conditions exist. This temperature preference helps to explain the consistently limited
distribution of dogfish on the Grand Banks. Because they are at the northern extent of
their range, and because they specifically aggregate in temperatures from 6 – 10oC,
temperature change could be a stressor to this CP in the future.
Temperature changes are not likely to be significant over the next 10 years unless annual
fluctuations in temperature are much greater than the average predicted change. Screened
out.
Key Activities/Stressors:
 Gillnet (bottom)
12
Reference List
1. Atlantic States Marine Fisheries Commission, S. D. P. D. T. (2002). Interstate
Fishery Management Plan for Spiny Dogfish (Rep. No. 40).
2. Bundy, A. (2003). Proceedings of the Canada/US Information Session on Spiny
Dogfish (Rep. No. 2003/019).
3. Campana, S. E., Gibson, J. F., Marks, L., Joyce, W., Rulifson, R., & Dadswell, M.
(2007). Stock structure, life history, fishery and abundance indices for spiny dogfish
(Squalus acanthias) in Atlantic Canada (Rep. No. 2007/089).
4. Cummings, J. & Brandon, N. (2004). Sonic Impact: A Precautionay Assessment of
Noise Pollution from Ocean Seismic Suveys Greenpeace.
5. Fisheries and Oceans Canada (2006). Impacts of trawl gears and scallop dredges on
benthic habitats, populations and communities (Rep. No. Science Advisory Report
2006/025). Canadian Science Advisory Secretariat, National Capital Region.
6. Fordham, S. (2004). Conservation and Management Status of Spiny Dogfish Sharks
(Squalus acanthias) (Rep. No. AC20 Inf. 22).
7. Germany (2007). Inclusion of Spiny Dogfish Squalus acanthias in Appendix II (Rep.
No. CoP 14 Prop. 16).
8. Government of Canada (2007). National Plan of Action for the Conservation and
Management of Sharks Fisheries and Oceans Canada, Communications Branch.
9. Jacques Whitford (2003). Strategic Environmental Assessment Laurentian
Subbasin.
10. Jacques Whitford (2007). Strategic Environmental Assessment Sydney Basin
Offshore Area.
11. Kulka, D. W. (2006). Abundance and Distribution of Demersal Sharks on the
Grand Banks with Particular Reference to the NAFO Regulatory Area (Rep. No.
06/20).
12. Marine Institute (1993). Atlantic Spiny Dogfish. Fisheries and Oceans Canada [Online]. Available: http://www.mi.mun.ca/mi-net/fishdeve/dogfish.htm
13. Pelot, R. & Wootton, D. (2004). Maritime traffic distribution in Atlantic Canada to
support an evaluation of a Sensitive Sea Area proposal (Rep. No. 2004-05).
Maritime Activity & Risk Investigation Network.
14. UNEP & UNFCCC (2002). Climate Change Information Kit UNEP and UNFCCC.
13
Spiny dogfish pupping in the St. Pierre Bank
Gillnet (bottom)
Magnitude of Interaction
Areal extent:
 The largest catch rates and the greatest proportion of sets with spiny dogfish were
associated with 6-10°C, which effectively restricts their distribution primarily to the
western extent of the St. Pierre Bank where sufficiently warm thermal conditions
exist. This temperature preference helps to explain the consistently limited
distribution of dogfish on the Grand Banks. The spiny dogfish are at the northern
limit of their distribution in Newfoundland and Labrador waters (Kulka, 2006).
 Spiny dogfish concentrate on the Western portion of the St. Pierre Bank adjacent to
the Laurentian Channel and onto the Hermitage Channel (Kulka, 2006).
 Sexually mature and pregnant females were distributed throughout the waters of
southwest Nova Scotia and the Bay of Fundy during the summer and fall, but moved
offshore to deeper waters in the winter. Females of mature size have also been
observed in the southern Gulf of St Lawrence and off southern Newfoundland
(Campana et al., 2007).
 Distribution of mature female spiny dogfish in summer research surveys, 1993-2005
are shown below:
Figure 1. Distribution of female spiny dogfish of mature size (FL>73 cm) in summer
research surveys from 1971 – 2004 (Campana et al., 2007).

Small juveniles are seldom collected in either Canadian or U.S. research surveys, but
those that are collected are found in the same areas as the mature females in winter. It
appears likely that the small juveniles pursue a largely pelagic existence for the first
few years of their lives before moving onto the continental shelf (Campana et al.,
1
Figure 2. Distribution of spiny dogfish on the Grand Banks, kg per tow 1971-2005
Canadian spring trawl survey (Kulka, 2006)

Over the past ten years, the area occupied by spiny dogfish on the Grand Banks has
diminished, by about five times. During this same period, spiny dogfish indices on the
Scotian Shelf have increased (Kulka, 2006).
Figure 3. Area occupied by spiny dogfish on the Grand Banks

Gillnet fishing occurs throughout much of the EBSA. We have calculated an areal
extent of 4,728 km2 based on gillnet fishing data from 1998-2007.
Figure 4. Areal extent of gillnet use in St. Pierre Bank 1998-2007, Newfoundland Region
fisheries (Fisheries and Oceans Canada, 2008)
2

Based on this information we have estimated the area of overlap to be 40%.
Score 4
Contact:
 Quantitative Fishing Gear Scores (Fisheries and Oceans Canada, 2007b) for contact
between bottom gillnets and elasmobranch - sharks, are moderate (often: >25 and <75
% of the time).
 Atlantic cod, skate/monkfish, white hake, and Greenland halibut are fished with
bottom gillnet (Appendix A, Table 8). Offshore license holders are limited to 40-500
(depending on the target species) nets that are 91m in length and are usually joined
together (Appendix A, Table 8). This amounts to a maximum of 45.5km of net per
license holder.
 Spiny dogfish concentrate on the Western portion of the St. Pierre Bank adjacent to
the Laurentian Channel, in water depths of 100 to 250 m (see image below).
Figure 5. Distribution of shark species by depth, Grand Banks to Labrador Shelf. Data are
from NL trawl surveys, 1971-2005 (Kulka, 2006).



The St. Pierre Bank EBSA includes the northwest St. Pierre Bank, south and west of
the Canada-France boundary, to the 200m isobath. Gillnets are therefore set less deep
here than they are in other areas of the LOMA, increasing the likelihood of capture.
Spiny dogfish pupping is a function of mature females, which are typically found near
the bottom (Campana et al., 2007; Kulka, 2006). Gillnets are set on the bottom.
The score assigned is at the high range suggested by the Quantitative Fishing Gear
Scores (Braune et al., 2001) since gillnet is commonly used in the EBSA, and is noted
as the main source of bycatch of spiny dogfish on the Grand Banks (Kulka, 2006).
Score 7.5
Duration:
 All evidence indicates that the mating and birthing of spiny dogfish takes place in the
winter months off the south-east coast of the United States. During the breeding
season, sexually mature dogfish form large schools (Marine Institute, 1993).
 Sexually mature and pregnant females were distributed throughout the waters of
southwest Nova Scotia and the Bay of Fundy during the summer and fall, but moved
offshore to deeper waters in the winter. Females of mature size have also been
3



Pupping grounds have not been observed in either Canadian or U.S. waters. However,
large aggregations of mature females occur in deep warm waters off the edge of the
continental shelf and in the deep basins of the central shelf throughout their range in
the winter (Fisheries and Oceans Canada, 2007a).
Bottom gillnet fishing is generally open from:
o May 15 – Nov 15 for cod
o May 19 – Dec 19 for Greenland halibut
o May 19 – Feb 28 for skate/monkfish and white hake
Therefore, gillnet may be in use for approximately 8 months in this EBSA. Pupping is
said to occur in the ‘winter months’ which we will assume to be December- February.
The cod gillnet fishery closes in November, but the other fisheries may continue until
the end of February. Therefore, some gillnetting occurs during the entire pupping
period. Temporal overlap is therefore approximately 100%.
Score 10
Intensity:
 Halpern et al. (2008) have developed maps showing the global intensity of several
anthropogenic stressors including ‘demersal non-destructive fishing with high
bycatch’, which includes bottom gillnet fisheries (see Fig. 6 below). This map can be
used to provide guidance in scoring the intensity of a stressor in relation to maximum
intensity in a global context, in accordance with the scale provided below
 Halpern’s map shows a medium high (yellow-orange) intensity for the St. Pierre
Bank EBSA relative to global levels, for a score range of 40% to 80%.
Map colour
Red
Orange
Yellow
Light Blue
Dark Blue
Intensity
80-100%
60-80%
40-60%
20-40%
0-20%
Figure 6. Global intensity of demersal non-destructive fisheries with high bycatch, which
include gillnets, adapted from (Halpern et al., 2008).


Gillnet fisheries within the EBSA accounted for an average of 33% of the landings
from 1998-2007 (Fisheries and Oceans Canada, 2008).
Since gillnet had the second highest landings of any gear type in the EBSA, the score
assigned will be in the high range suggested by Halpern.
Score 8
4
Magnitude of Interaction: (4 x 7.5 x 10 x 8)/1000 = 2.4
Sensitivity
Sensitivity of the CP to acute impacts:
 Quantitative Fishing Gear Scores (Fisheries and Oceans Canada, 2007c) for harm
resulting from an interaction between bottom gillnets and elasmobranch- sharks, are
high (usually: >75%).
 The index of abundance for spiny dogfish is highly variable, without trend. Given
their highly aggregated distribution and migratory behaviour, it is unlikely that theses
patterns reflect trends in population size (Kulka, 2006).
Figure 7. Biomass estimates of Squalus acanthias pups, Northwest Atlantic (Fordham,
2004).





Within fisheries regulations, the spiny dogfish is defined as a groundfish species and
is governed by the groundfish Integrated Fish Management Plan. Harvesting of
dogfish was capped at 2,500 tonnes in 2002. This was the first quota applied to
species and was in response to the need to conduct further research on this species
and its populations in order to establish sustainable harvest levels (Government of
Canada, 2007).
Quotas to this point have not been based on scientific advice, and there are no
restrictions on discarding and bycatch in other fisheries (Campana et al., 2007).
The principal threat to this species is from overexploitation in target and bycatch
fisheries (Atlantic States Marine Fisheries Commission, 2002).
Over the past ten years, the area occupied by spiny dogfish on the Grand Banks has
diminished, by about five times (Kulka, 2006).
Mortality due to fishing in the Canadian portion of the Grand Banks has been
estimated at an average of 14 t annually between 1996 and 2005. There is no directed
fishery in the area but spiny dogfish are taken incidentally in a number of fisheries
(see Table 1) (Kulka, 2006).
5
Table 1: Commercial bycatch of spiny dogfish in Canadian fisheries on the Grand Banks,
1996 to 2005 (Kulka, 2006)


Spiny dogfish are relatively hardy, so it is only reasonable to assume that discard
mortality is not 100%. Unfortunately, there are few available estimates for dogfish
discarding mortality. 4X accounts for most of the dogfish in Atlantic Canada
(Campana et al., 2007).
Total discards have averaged 2,000-3,000 tonnes annually in recent years, although
discards of up to 10,000 tonnes were estimated for some years in the 1990s (Fisheries
and Oceans Canada, 2007a).
6
Figure 8. Total catch and discard mortality of spiny dogfish caught in Canadian waters
since 1986 (Fisheries and Oceans Canada, 2007a).



The spiny dogfish is migratory and usually strongly aggregated by age and sex,
making it easy for fishers targeting them to maintain catches despite stock depletion
and to target the most valuable part of the stock (large, pregnant females). It also
means that non-target fisheries may remove concentrations of mature females
incidentally. Heavily exploited populations become male biased with associated
reduction in pup production (Campana et al., 2007).
Spiny dogfish were observed in the trawl surveys (and in commercial catches) in all
months of the year, the highest catches occurring in the winter and spring months
(Kulka, 2006), which is when pupping takes place.
Acute sensitivity is scored high because spiny dogfish are caught in gillnets
throughout the year; large pregnant females aggregate; there is a direct harvest by
Nova Scotia fisheries; there is no regulations on discarding; their area has
diminished; they are red-listed as ‘Vulnerable’; and biomass estimates are unknown.
Score 8
Sensitivity of the CP to chronic impacts:
 This species is exceptionally slow-growing and long-lived and therefore especially
prone to rapid over-exploitation and long-lasting depletion (Fordham, 2004).
 Smith et al. (1998) found spiny dogfish to have the lowest intrinsic rebound potential
of 26 shark species analyzed. These factors, combined with the tendency of fisheries
to target the reproductive females (due to their large size), make the species
particularly prone to depletion (Fordham, 2004).
 The 2003 IUCN Red List assessment ranks spiny dogfish as “Near Threatened” on a
global basis. The Northwest Atlantic population is currently assessed as
“Vulnerable”, based on past fisheries records, stock assessments, and continued
unsustainable exploitation (Fordham, 2004).
 Spiny dogfish are ovoviviparous, with the young feeding and growing off a yolk sac
in utero before being born alive. This reproductive cycle takes 22-24 months, making
it one of the longest gestation periods known for any vertebrate (Campana et al.,
2007), and therefore susceptible to fishery impacts for a very long duration.
7

The Canadian survey index of abundance for spiny dogfish on the Grand Banks is
highly variable, without trend (see Figure 9 below). Given their highly aggregated,
restricted distribution and migratory behaviour, it is unlikely that the survey indices
reflect trends in population size. Spiny dogfish are patchy and form dense
aggregations (closely spaced sets ranging from zero to thousands of animals per set)
which causes high variance and spikes in the survey indices. Over the past ten years,
the area occupied by spiny dogfish on the Grand Banks has diminished (Kulka,
2006).
Figure 9. Biomass estimates of Squalus acanthias pups, Northwest Atlantic) (Fordham,
2004).




It is not currently possible to estimate trends in mature female biomass for spiny
dogfish in Atlantic Canada (although the most recent Canadian biomass value is
about 350,000 tonnes, corresponding to about 200 million fish). Without knowing
the extent that Canadian spawners contribute to the health of northwest Atlantic
dogfish metapopulation, it may not be wise to increase the exploitation rate on mature
females (Campana et al., 2007).
Northwest Atlantic landings peaked in 1974 at about 25 000 tonnes then again in
1996 at about 28 000 tonnes, the USA fishery dominating from 1979 to 2000. Total
landings have declined steadily since 1998. Since 2000, the Canadian catches
(Scotian Shelf) are the largest proportion of estimated landings and recreational
catches are, for the first time, a significant proportion of total landings (about 2 500 3 500 tonnes catches in 2000-2002). Although discarding has declined in recent years,
total catch mortality in previous years may have been much higher than reported
landings (Kulka, 2006).
Canada began restricting dogfish catch in May of 2002, following a significant
increase in landings in years just prior. The government capped 2002 commercial
landings at 2500 tonnes for the fixed-gear groundfish sector off Nova Scotia and in
the Bay of Fundy, based on landings history at the time. In addition, bycatch caps for
other fisheries consistent with historical landings and an additional 700 tonnes for a
cooperative industry sampling program were granted. The Canadian government has
stated that the caps are aimed to limit exploitation while future sustainable catch
levels are investigated (Fordham, 2004).
Since this CP is extremely vulnerable to over-exploitation and has one of the longest
gestation periods for any vertebrate, this factor scores high.
Score 9
8
Sensitivity of ecosystem to harmful impacts to the CP:
 Spiny dogfish have many characteristics of a metapopulation, whereby some dogfish
aggregations colonize or depart Canadian waters en masse at periodic multi-year
intervals, and then remain resident in those waters for many years at a time. The
existence of a metapopulation would imply that managing northwest Atlantic dogfish
as a single, well-mixed stock would be inappropriate. The Canadian dogfish cannot
be viewed in isolation. It is possible that a fishery on mature females in either
Canadian or U.S. waters could impact the abundance in all areas (Campana et al.,
2007).
 The diet of this species is highly varied as these are opportunistic predators. In the
waters off Newfoundland, they feed mainly on small fishes including capelin, herring,
and Atlantic cod (Jacques Whitford, 2003; Kulka, 2006). Atlantic mackerel and
Loligo and Illex squid are also important components of the diet of spiny dogfish
when they are abundant and available (Atlantic States Marine Fisheries Commission,
2002).
 They have few natural predators. Predaceous bony fishes and sharks prey upon the
newly born (Jacques Whitford, 2003; Kulka, 2006). Studies have identified sharks
(mackerel, great white, tiger, blue), barndoor skate, lancetfish, bluefin tuna, tilefish
and goosefish as predators of spiny dogfish (Atlantic States Marine Fisheries
Commission, 2002).
Score 4
Sensitivity: (8 + 9 + 4)/3 = 7
Risk of Harm: 2.4 x 7 = 16.8
9
Certainty Checklist
Answer yes or no to all of the following questions. Record the number of NOs to the 9
questions, and record certainty according to the scale provided below:
1
No’s = High certainty
2 - 3 No’s = Medium certainty
No’s = Low certainty
>4
Y/N
Y Is the score supported by a large body of information?
N Is the score supported by general expert agreement?
N Is the interaction well understood, without major information gaps/sources of error?
Y Is the current level of understanding based on empirical data rather than models,
anecdotal information or probable scenarios?
Y Is the score supported by data which is specific to the region, (EBSA, LOMA, NW
Atlantic?
Y Is the score supported by recent data or research (the last 10 years or less)?
Y Is the score supported by long-term data sets (ten year period or more)?
Y Do you have a reasonable level of comfort in the scoring/conclusions?
N Do you have a high level of confidence in the scoring/conclusions?
Certainty Score: Medium
For interactions with Low certainty, underline the main factor(s) contributing to the
uncertainty:
Lack of comprehensive data
Lack of expert agreement
Predictions based of future scenarios which are difficult to predict
Other (provide explanation)
Suggest possible research to address uncertainty.
Research to identify the habitat for pupping and the juvenile pelagic stage, and to
quantify pup abundance, would aid in predicting stock abundance and determining
stock composition.
A better understanding of the metapopulation dynamics in this area would help
determine if migrating spiny dogfish are incurring stressors in areas outside the
LOMA. There seems to be lack of agreement as to what proportion of the
population undergoes migration to more southern areas, as well as what proportion
move inshore.
10
Reference List
1. Atlantic States Marine Fisheries Commission, S. D. P. D. T. (2002). Interstate
Fishery Management Plan for Spiny Dogfish (Rep. No. 40).
2. Braune, B. M., Donaldson, G. M., & Hobson, K. A. (2001). Contaminant residues
in seabird eggs from the Canadian Arctic. Part I. Temporal trends 1975–1998.
Environmental Pollution, 114, 39-54.
3. Campana, S. E., Gibson, J. F., Marks, L., Joyce, W., Rulifson, R., & Dadswell, M.
(2007). Stock structure, life history, fishery and abundance indices for spiny dogfish
(Squalus acanthias) in Atlantic Canada (Rep. No. 2007/089).
4. Fisheries and Oceans Canada (2007a). Assessment of Spiny Dogfish in Atlantic
Canada (Rep. No. 2007/046).
5. Fisheries and Oceans Canada (2007b). Draft proceedings of the Workshop on
Qualitative Risk Assessment of Fishing Gears. In Government of Canada.
6. Fisheries and Oceans Canada (2007c). Placentia Bay-Grand Banks Large Ocean
Management Area Conservation Objectives (Rep. No. 2007/042). Canadian Science
Advisory Secretariat Science Advisory Report.
7. Fisheries and Oceans Canada. (2008). 1998-2007 3LMNOP4R Effort and Catch.
Policy and Economics Branch. [Newfoundland and Labrador Region Catch and
Effort]. Fisheries and Oceans Canada.
Ref Type: Data File
8. Fordham, S. (2004). Conservation and Management Status of Spiny Dogfish Sharks
(Squalus acanthias) (Rep. No. AC20 Inf. 22).
9. Government of Canada (2007). National Plan of Action for the Conservation and
Management of Sharks Fisheries and Oceans Canada, Communications Branch.
10. Halpern, B. S., Walbridge, S., Selkoe, K. A., Kappel, C. V., Micheli, F., D'Agrosa,
C. et al. (2008). A Global Map of Human Impact on Marine Ecosystems. Science,
319, 948-952.
11. Jacques Whitford (2003). Strategic Environmental Assessment Laurentian
Subbasin.
12. Kulka, D. W. (2006). Abundance and Distribution of Demersal Sharks on the
Grand Banks with Particular Reference to the NAFO Regulatory Area (Rep. No.
06/20).
13. Marine Institute (1993). Atlantic Spiny Dogfish. Fisheries and Oceans Canada [Online]. Available: http://www.mi.mun.ca/mi-net/fishdeve/dogfish.htm
11
Summary Table: Spiny dogfish pupping in the St. Pierre Bank
Key
Activity/Stressor
a
Gillnet (bottom)
4
c
d
i
MoI
as
cs
es
8
9
4
(a x c x d x i)
1000
7.5 10
8
2.4
S
Risk
(as+cs+es) of
3
Harm
7
16.8
Cumulative CP Score 16.8
Certainty
Med