Article: Hällekis industrier sedda fr utsiktstornet på Kinnekulle 6116.jpg
Distant view of lake from Kinnekulle
Detail map of the lake with surroundings
region:SE_type:waterbody_scale:1500000
Brommö, Djurö, Fågelö, Hammarö, Kållandsö, Lurö (22,000 in total, including skerries)
Vänern ( , , ) is the largest lake in Sweden, the largest lake in the European Union and the third-largest lake in Europe after Ladoga and Onega in Russia. It is located in the provinces of Västergötland, Dalsland, and Värmland in the southwest of the country. With its surface located at with a maximum depth of , the lowest point of the Vänern basin is at below sea level. The average depth is at a more modest , which means that the average point of the lake floor remains above sea level.
Vänern drains into Göta älv towards Gothenburg and the Kattegat tributary of the Atlantic Ocean. It is the only one of the ten largest lakes in Sweden not to drain on the country's eastern coastline. Due to the construction of Göta Canal in the 19th century, there is an upstream water path to Vättern and the east coast from Vänern. The main inflow of water comes from Klarälven entering Vänern near Karlstad with its source in Trøndelag in Norway.
History
The southeastern part of the Vänern is a depression that appears to have come into being by erosion of Paleozoic-aged sedimentary rock during the Quaternary glaciation that reached to the area. This erosion would have re-exposed parts of the Sub-Cambrian peneplain. Because the southern and eastern shores are parts where the Sub-Cambrian peneplain gently tilts towards the north and west, respectively, the lake is rather shallow at these places. The western shore of the lake largely follows a fault scarp associated to Vänern-Göta Fault.
The modern lake was formed after the Quaternary glaciation about 10,000 years ago; when the ice melted, the entire width of Sweden was covered in water, creating a strait between Kattegat and the Gulf of Bothnia. Due to the fact that ensuing post-glacial rebound surpassed concurrent sea-level rise, lake Vänern became a part of the Ancylus Lake that occupied the Baltic basin. Vänern was connected to Ancylus Lake by a strait at Degerfors, Värmland. Further uplifting made lakes such as Vänern and Vättern become cut off from the Baltic. As a result, there are still species remaining from the ice age not normally encountered in freshwater lakes, such as the amphipod Monoporeia affinis. A Viking ship was found on the lake's bottom on May 6, 2009.
A story told by the 13th-century Icelandic mythographer Snorri Sturluson in his Prose Edda about the origin of Mälaren was probably originally about Vänern: the Swedish king Gylfi promised a woman, Gefjon, as much land as four oxen could plough in a day and a night, but she used oxen from the land of the giants, and moreover uprooted the land and dragged it into the sea, where it became the island of Zealand. The Prose Edda says that 'the inlets in the lake correspond to the headlands in Zealand'; since this is much more true of Vänern, the myth was probably originally about Vänern, not Mälaren.
The Battle on the Ice of Lake Vänern was a 6th-century battle recorded in the Norse sagas and referred to in the Old English epic Beowulf. In Beowulf, Vänern is stated to be near the location of the dragon's mound at Earnaness.
Geography
Vänern covers an area of , approximately twice the surface area of Luxembourg. Its surface is above sea level and it is on average deep. The maximum depth of the lake is The water level of the lake is regulated by the Vargön Hydroelectric Power Station.
Geographically, it is situated on the border between the Swedish regions of Götaland and Svealand, divided between several Swedish provinces: The western body of water is known as the Dalbosjön, with its main part belonging to Dalsland; the eastern body is known as Värmlandsjön, its northern part belonging to Värmland and the southern to Västergötland.
Its main tributary is Klarälven, which flows into the lake near the city of Karlstad, on the northern shore. Other tributaries include Gullspångsälven, Byälven and Norsälven. It is drained to the south-west by Göta älv, which forms part of the Göta Canal waterway, to Lake Viken into Lake Vättern, southeast across Sweden.
The economic opportunities Vänern offers are illustrated by the surrounding towns, which have supported themselves for centuries by fishing and allowing easy transportation to other cities or west by Göta älv to the sea of Kattegat. This directly includes: Karlstad (chartered in 1584), Kristinehamn (1642), Mariestad (1583), Lidköping (1446) Vänersborg (1644), Åmål (1643), Säffle (1951), and indirectly Trollhättan (1916).
The Djurö archipelago surrounds the island of Djurö, in the middle of the lake, and has been given national park status as Djurö National Park.
The ridge (plateau mountain) Kinnekulle is a popular tourist attraction near the south-eastern shore of Vänern. It has the best view over the lake (about above the lake level). Another nearby mountain is Halleberg.
Environment
Environmental monitoring studies are conducted annually. In a 2002 report, the data showed no marked decrease in overall water quality, but a slight decrease in visibility due to an increase of algae. An increasing level of nitrogen had been problematic during the 1970s through 1990s, but is now being regulated and is at a steady level.
Some bays also have problems with eutrophication and have become overgrown with algae and plant plankton.
Fish
Vänern has many different fish species. Locals and government officials try to enforce fishing preservation projects, due to threats to the fish habitat. These threats include water cultivation in the tributaries, pollution and the M74 syndrome. Sport fishing in Vänern is free and unregulated, both from the shore and from boats (with some restrictions, e.g. a maximum of three salmon or trout per person per day). Commercial fishing requires permission.
In the open waters of Vänern, the most common fish is the smelt (Osmerus eperlanus), dominating in the eastern Dalbosjön, where the average is 2,600 smelt per hectare. The second most common is the vendace (Coregonus albula), also most prominently in Dalbosjön, with 200–300 fish per hectare. The populations may vary greatly between years, depending on temperature, water level and quality.
The most important large fish in the lake are brown trout (Salmo trutta) and zander (Sander lucioperca). The most important small fish is the stickleback.
Vänern has five distinguished species of whitefish:
Coregonus pallasii (also common in Neva, Gulf of Finland, Baltic Sea)
Lacustrine fluvial whitefish (Coregonus megalops)
Coregonus maxillaris (population mainly known around Sweden)
Coregonus nilssoni
Valaam whitefish (Coregonus widegreni)
Coregonus maxillaris Birds
The most common birds near Vänern are terns and gulls.
Great cormorants have returned and are flourishing. This has contributed to the increase in the population of white-tailed sea eagles, who feed on cormorants.
See also Hindens Rev Lakes of Sweden References External links Official site
Väner museum i Lidköping |
Source: Home Salmonidae Salmoniformes Atlantic Salmon Article PDF Available
Atlantic Salmon and Brown Trout in Lake Vänern: A proposal for a co-management system
October 2014
Aquatic Ecosystem Health & Management 17(4):365-373
DOI: 10.1080/14634988.2014.965119 Authors: Eva Bergman Karlstads Universitet Johnny R Norrgård Gammelkroppa Lax AB John J Piccolo Karlstads Universitet Pär Gustafsson Independent Researcher
Show all 6 authors
Hide Download full-text PDF Read full-text Download full-text PDF Read full-text Download citation Copy link Link copied Read full-text Download citation Copy link Link copied Citations (7) References (42) Abstract
Co-management is of increasing interest for fisheries management. We explore possibilities for, and
barriers to, developing a co-management system, using threatened populations of landlocked Atlantic
Salmon and Brown Trout as examples. Good management of natural resources requires not only
knowledge about the resource, but also suitable tools to collect information and make decisions. In
large ecosystems this can be difficult because many actors are involved, and various societal borders
and traditions become barriers. V€anern is the largest lake in the European Union and it holds several
distinct populations of large-bodied landlocked Atlantic Salmon and Brown Trout. The lake is used for
commercial, subsistence, and sport fishing as well as for other recreational activities; in Klar€alven, the
largest river entering V€anern, sport fishing is popular. These salmonid populations were at critically
low levels during the 1960s, but a stocking program since then has maintained the fishery. At least one
wild stock appears to be recovering since being protected in 1993. Ecosystem users all have different
needs: in the lake, sport fishermen say that catches of hatchery fish have declined, and commercial
fishermen have focused on other species. In the river, wild salmon may be recovering: sport fishing is
popular and an ongoing project investigates the possibilities for salmon to be able to circumvent hydroelectrical
plants and reach historical Norwegian spawning areas. Not only do we lack information
about the salmonids’ different life stages, we also lack a suitable socio-political organization to find
sustainable solutions to the different needs of diverse user groups. We argue that a co-management
system that enfranchises user groups in the V€anern-Klar€alven ecosystem will improve sustainable
management of wild and hatchery fish.
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Atlantic Salmon and Brown T
rout in Lake Vänern: A
proposal for a co-management system
Eva Bergman a
, Johnny R. Norrgård
a
, John J. Piccolo
a , Pär Gustafsson b , Fredrik Nilsson c &
Paul J. B. Hart
d a Department of Biology , Karlstads University
, Karlstad S-651 88, Sweden
b
County Administrative Board of Värmland, Karlstad S-651 86, Sweden
c
County Administrative Board of Västra Götaland, Vänersborg S-462 82, Sweden
d Department of Biology
, University of Leicester
, Leicester LE17RH, UK
Accepted author version posted online: 25 Sep 2014.
T
o cite this article:
Eva Bergman, Johnny R. Norrgård, John J. Piccolo, Pär Gustafsson, Fredrik Nilsson & P
aul J. B. Hart
(2014): Atlantic Salmon and Brown T
rout in Lake Vänern: A proposal for a co-management system, Aquatic Ecosystem Health
& Management T
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Atlantic Salmon and Brown Trout in Lake Vänern: A proposal for a
co-management system Eva Bergman 1
*, Johnny R. Norrgård
1
, John J. Piccolo
1 , Pär Gustafsson 2 , Fredrik Nilsson 3 , Paul J. B. Hart 4 1
Department of Biology, Karlstads University, Karlstad S-651 88, Sweden
2
County Administrative Board of Värmland, Karlstad S-651 86, Sweden
3
County Administrative Board of Västra Götaland, Vänersborg S-462 82, Sweden
4
Department of Biology, University of Leicester, Leicester LE17RH, UK
* Corresponding author: eva.bergman.1868@kau.se ,
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ACCEPTED MANU SCRIPT ACCEPTED MANU SCRIPT 2 Abstract Co-management is of increasing in terest for fisheries management. We explore possibilities for, and barriers to, developing a co-management system, using threatened populations of landlocked At lantic Salmon a nd Brown T rout as examples. Goo d management o f
natural resources requires not only knowledge about t
he resource but also suitable tools to collect
information and make decisions. I n large ecosystems this ca n be di fficult because many actors are involved, and various soc ietal borders and t raditions become barriers. Väner n is the largest lake in the EU an d it h o lds several distinct populations of large-bodied landl ocked Atlantic
Salmon and Brown Trout. T
he lake is used for commercial, subsistence, and spo
rt fishing as well
as f or other recreational activities, and in Klarälven, the largest river entering Vänern, sport
fishing is popular. These
salmonid populations were at critically low
levels during the 1960s,
but a sto cking program since t hen has maintained the fishery, and at least one wild st ock appears to be r ecovering since being prot ected in 1993. Ecosystem users all have different needs: in the lake, sport fishermen s ay that cat ches of hatchery fish have dec lined, and commercial fishermen have focused on o ther species. In the r iver, w ild salmon may be recovering: s port fishing is popular and an o ngoing project investigates t he possibilities for salmon to be able t o circumvent hydro-electrical plants and reach historical Nor wegian spawning areas. Not only do we l ack information about t he salmonids’ different life stages, we also lack a suitable socio-political organization to find sustainable so lutions to t
he different needs o
f diverse user groups. We argue that a co-management system that e nfranchises user groups in the Väner n-Klarälven ecosyste m
will improve sustainable management of wild and hatchery fish.
Keywords :
fishery, barriers, bi-national-ecosystem, scientists, managing author
ities, stakeholder
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ACCEPTED MANU SCRIPT ACCEPTED MANU SCRIPT 3 Introduction
To manage natural resources such as wild salmonid populations, we need good
knowledge about the ecosystem, but we also need to overcome several sociopolitical, economic,
intellectual and communicational barriers (Jacobsen et al., 2011). For migratory salmonids there
is a need to understand the entire life cycle of the species, including both lake and river stages
(Jonsson and Jonsson, 2011), despite the fact that most scientists work in either one or the ot
her
of these two ecosystems. Once research needs are determined, a monitoring program must be
established to assess the effects of management decisions. Another barrier to progress is poor
communication between scientists, managing authorities and user gro
ups (Jacobsen et al., 2011).
Finally, funding needs to be secured to address research needs and maintain management and
monitoring programs. Fisheries management is most ly about managing people, but a goo d knowledge o f the re source is also requ ired to inf or m policy development (Pitcher and Hart , 1982). For a large water body where resources are limi ted i t can be d ifficult to obtain e nough dat a to al low sound scientific advice. One way to deal with this is to form a partnership with the fishers who ex ploit the resource. T hey are out on t he lake for a goo d part of t he year and often have year s of experience
of the local conditions. This means that fishers can be employed to
gather data, and that their local
ecological knowledge can be gathered for evaluation and combined with scient
ific knowledge.
Efforts to bring fishers into the management system have been made through the establishment of
co-management institutions. Co-management is defined by Jentoft (2003) as
‘… a collaborative
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ACCEPTED MANU SCRIPT ACCEPTED MANU SCRIPT 4
and participatory process of regulatory decision-making between representatives of user-groups,
government agencies, research institutions, and other stakeholders’
. Co-management can be seen
as a continuous problem-solving process, focusing on joint learning and understanding of how
different management tasks are organized and solved (Walters 1986).
The 2012 S OLVE symposium (Stat e o f Lake Vänern Ecosystem) brought together scientists and resource managers f ro m Sweden, North America an d bey o nd to asses s the curre nt knowledge level and f uture research n eeds for the Vänern ecos ystem. Vä nern support s a total co mmercial fishery of o ver 600 tonnes a nd c 2. 9 million Euros per year. Although s almon and trout represent only a f raction of t he tot al co mmercial value (4%) of the fishery t heir eco logy and fishery has
been studied in some detail and the fish have an iconic status.
Both species are well-recognized by
the public and have high spor
t value due to a
large recreational fishery. In this p
aper we propose a
co-management syste m, using Vä nern’s migrato ry salmon ( Sal mo salar ) and t rout ( S. trutta ) as case stud ies. Vänern’s sa lmon and trout are also of interest because o f their re liance on both lake
and river habitats, so linking these ecosystems and their management.
The Väner-Klarälven ecosystem
The lake and river habitats
Lake Vä nern (58 O 55’N 13 O 30’ E) i s the largest lake in the E U, with a surface area o f over 5650 km 2 (
Willén, 2001). The lake
has a temperate
fish fauna that was
isolated from the sea
some 9000 years ago (Willén, 2001), and t
he salmonids are more related to t
he Baltic stocks than
to North Sea s tocks (Pal m e t al ., 2012). Klarälven (59°23’N 13°32’ 0’’ E) is the largest r iver entering Vä nern. I t begins in Swede n, a nd t hen f lows t hrough No rway and ba ck into Sweden
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before entering the lake (F
igure 1). The river ho
lds many fish species, for
example salmon, trout, grayling ( Thymallus thymallus ), whitefish ( Co regonus spp), and p ike ( E sox lucius ) . The salmon and Bro wn Trout grow to a large size and historically migrat ed as far as 400 km upstrea m to spawn in the northerly sections o f the r iver. Klarälven salmon is one of few stocks o f landlocked Atlantic Salmon in Euro pe and is prot ected by the EUs h abitat di rective. Today there are 11
power stations in t
he main river c
hannel (Figure 1)
but no functional up
- or downstream fishways. A number o f ot her rivers are k nown to have held migratory salmonid st ocks
historically (Ros, 1981), but today they are known only to remain Gullspångsälven and T
idan Salmonid management In the 1800s, catches in bot h Vänern a nd Klarälven were high, but decreased during t he 1900s to cri tically low levels in the 1960s, res embling many large rivers around t he world (Parrish et a l., 1998; Picco lo et al., 2012). T imber floatation and hydroelectric power and high fishing pres sure, lies behind these decreases (see Nordberg [1977] and Piccolo et a l. [2012] for historical details). After t he introduction o f Smolt stocking during t he 1970s, return rates have increased aga in (Figure 2) (Nordberg, 1977; Picco lo et al., 2012) .Today t he Vänern -Klarälven ecosystem h olds both wil d and hatchery reared stocks of At lantic Salmon and Brown Trout (Piccolo et al ., 2012). All h atchery S molts ar e released downst ream o f the l ast hy dro- electric plant (HE P) in Forshaga ( Figure 1) . S molt spend two or more years in the lake a nd as returning spawners they swim 25 km up Klarälven before reaching the first HEP at Forshaga (Figure 1). There being no fish passes t here is a “trap a nd hauling syste m” t o cat ch fish for bot h hatchery purposes and for tr ansportation to the spawning a reas. So me fish are taken for the hatchery, but
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ACCEPTED MANU SCRIPT ACCEPTED MANU SCRIPT 6 the rest are transported by truck past seven HEPs, and are re leased into the Klarälven again. Fish can reac h upstrea m spawning areas i n the Swedish part of the river. They ca nnot reac h the
pristine spawning areas in Norway (Nordberg, 1977).
Postspawners descend either directly after they spawn in early No vember o r after the winter in March. The Smolt
run occurs in May t
o early July and t
he outward migrating S
molts are commonly 2–3 years old ( Runnström, 1940; Norrgård et al., 2012; unpublished data). All
downstream migration occurs through power station turbines or spill gates.
Increasing wild population of salmon: A new pattern that
changes every t hing Prior to 1993 it was impossible to differentiate between wild and hatchery reared fish. Since then, all hatcher y fish have received an ad ipose-fin c lip, and t here is a no-catch regu lation
for wild salmon and tr
out in the lake (Fisker
iverket, 1993). The number of w
ild salmon returning to F orshaga h as i ncreased since 1996 (Figure 3), while ret urn rates of hatchery sa lmon have decreased slightly (P iccolo et a l., 2012). The pr oportion of wild salmon a nd trout combined in the commercial catch in Vä nern has increased from a maximu m of 5% in 1997 (Fiskeriverket and Länsstyrelsen i Vär mlands län, 1998) to up to 30–50% by 2008 (Degerman, 2008; Hållén, 2008; Johansson et al., 2009). T
he increasing proportion o
f wild fish in t
he lake co
uld be a result
of (1) in creased natural production a nd/or p rotection o f wild f ish, a nd (2) decl ining n umbers and/or decreased survival o f hatchery Smolt ( Eriksson et al., 2008). It is important to note that there is much uncertainty in the hat chery re lease data and catch statistics (P iccolo et al., 2012),
and that the m
ost obvious trend is the increasing returns
o f wild salm o
n to Forshaga, and
apparent increasing pro portions of wild fish caught in Vänern. S
ome of this u
ncertainty could be
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ACCEPTED MANU SCRIPT ACCEPTED MANU SCRIPT 7 reduced in a co-
management system through fis
hers gathering more systematic data on
t he
species composition of catches.
What we know and don’t know
Until recently, m uch rese arch is f ocused on achieving an est imate of t he numbers o f salmonids in their different life stages in the river , including both t he do wnstream and up stream migration phase s in t he Swed ish sect ion. Wild a nd hatcher y reared fi sh have been studied. In 2009 only about 20% of downstream migrating wild Smolt passed a ll eight HE Ps (Norrgård et al., 2012; F igure 1). Among-year-variation has not been studied, and survival might be higher in some years.
Predation from both in-stream predators and terrestrial mammals or birds might add to t
he
mortality caused by HEPs so limiting the population size of salmonids. In 2012 we explored the
activity pattern and diet of pike in the lower part of Klarälven during the Smolt run. Co
ncurrent
studies explore migration behavior of both wild and hatchery reared Smolt in the same area and
preliminary result show larger migration success for wild than hatchery reared Smolts.
Experimental work has also shown that migratory behavior of Smolts is influenced by feeding
regime and food quality (Lans et al. 2011; unpublished data). Studies of the upstream migrat
ion of
spawners and downstream migration of kelts started in 2011. These explored the upstream and
downstream migration of early and late ascending Atlantic Salmon, wild and hatchery reared
Atlantic Salmon, and Brown Trout. Aspects studied were the type of fish (i.e. w
ild or hatchery),
the timing of migration, and the importance of gender and size. Concurrently we also follow
ascending Atlantic Salmon in the lower part of the river, below the HEP closest to the lake, to
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explore their migration and evaluate the efficiency of the fish trap at the Forshaga HEP.
A
population model to describe the status of Atlantic Salmon in the Vänern-Klarälven ecos
ystem is
being developed based on our Smolt, spawner and kelt studies together with population estimates
from other sources, including the Norwegian Institute for Nature Research (NINA), No
rway, and
the Värmland County Administrative Board. There are also ongoing genet
ic analyses of the
different Vänern salmonid stocks by the Swedish University of Agricultural Sciences (SLU)
(Piccolo et al., 2012; Palm et al. 2012). Additional input from fishers would also be welcome but
at present there is no easy way to obtain this. A formalized co-management s
ystem would provide
the appropriate forum within which fishers could make their contribut
ion.
In Vänern we still lack effort-related monitoring data on the present co
mmercial, subsistence, and
sport fishery for salmon and trout (Piccolo et al., 2012). It is in this area that a co-management
system could make an important contribution as fishers, both recreational and commercial, are out
on the lake for many days of the year and could easily contribute data on effort. Data on total
catches exist on commercial, but not subsistence, fishery but there is a lack of data on effort. Unt
il
recently salmon and trout data were pooled so degrading the historical record. Recreational
catches of hatchery reared fish in the lake is free and catches are not reported, but in 2013 a new
study to estimate sport fishing pressure on the lake was started. In Klarälven it
is possible to fish
both wild and hatchery reared fish downstream of the 1
st HEP
in Forshaga, the fishery is managed
by local landowner associations and total catches are reported annually. Piccolo et
al. (2012)
estimated that both commercial and subsistence fishery catches decreased during 1985-2009
whereas sport fishing catches increased to 50 tonnes. Alternative estimates o
f recreational catches
have shown a decrease from 50 to 20 tonnes between 1998 and 2011 (Johansson and Andersson,
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2011). There is an active but unreported sport fishery on wild and hatchery fish in the river
upstream of the Forshaga HEP.
Discussion
The potential for wild salmonids in Klarälven and Vänern
Nilsson (1979) proposed a food web for Vänern’s pelagic zone. His research
focused on
salmonids and their prey because they attract so much worldwide attention (Bottom et al., 2009).
They have unsurpassed food and sport value, and many populations are endangered (Piccolo,
2011 and references therein). When Nilsson (1979) studied Vänern, salmonid popu
lations were
at an all-time low, and as in many other ecosystems hatchery production seemed the logical
answer (Behnke, 2002). Indeed, hatchery production has brought Vänern’s salmonids back from
the brink of extinction while simultaneously maintaining a considerable commercial fishery. In
addition, a rapidly-expanding sport fishery has developed since hatchery production peaked in
the 1990s. Over the past decade, production of wild Smolt in Klarälven has increased
dramatically while survival of hatchery Smolts has decreased (Piccolo et al., 2012; unpublished
material). Authorities overseeing the Vänern ecosystem are now faced with difficult decisions as
to how the fish community and the fisheries ought to be managed: What emphasis s
hould be
placed on restoring wild, native salmonid populations in Klarälven, and other tributaries? To
what extent can hatchery production be replaced by wild production? How will continued
increases in wild fish affect survival of the hatchery Smolts upon which all o
f the fisheries
depend? Alternatively, how might proposed changes in strategies for the release of hatchery
Smolt influence the success of the wild fish conservation programs? And finally, how will the
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future management of Vänern’s salmonids effect the complex food web interact
ions of the lake
as a whole, and the myriad ecosystem services these provide to the region? Below we argue that
much key scientific knowledge about the Vänern ecosystem is still lacking, even for At
lantic
Salmon and Brown Trout, and that the most successful way to improve this situation might be to
develop a co-management system in which all stakeholders are engaged in the common goa
l of long-term sustainability. Barriers to overcome
Scientists are now expected to collaborate with a range of stakeholders to
produce good
management plans. For salmonids in the Vänern-Klarälven ecosystem we must develop a holistic
understanding of the ecosystem. This means producing knowledge of all stages of the life cycle
of salmon and trout, which will demand collaboration between habitat specialists. Furt
her, efforts
must develop communication between scientists, managing authorities and other stakeholders in
both Sweden and Norway. In addition, the large size of the catchment area of this ecos
ystem
generates complications. There are several separate authorities involved in the management o
f
the lake as there are two counties in each of the two countries involved in this bi-national-
ecosystem. This presents a major challenge!
Since the compensatory Smolt stocking started during the 60s data has been collected on the
stocked fish. Commercial and recreational fishermen have been involved in data collection but
neither group has a clear and unified goal for data collection and their numbers have decreased
(Brendan et al., 2010). Furthermore, as the goals have changed over time the “sample
characteristics” of the marked fish have varied, making it hard to evaluate the data set. For the
Vänern-Klarälven ecosystem, this means that despite long-ter
m data collection efforts, we still
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lack essential information of the salmonid populations and the role of hatchery reared salmonids
in the ecosystem. Although all elements of the ecosystem are being monitored (Vänerns
vattenvårdsförbund, 2011; AL Control, 2012), there is a strong need for well-coor
dinated
monitoring programs and for a continuous analysis of the data set.
A new management plan?
Ecosystem based fishery management is now a goal of many management agencies (Link,
2010). This recognizes the fact that fish resources are embedded in an ecosystem, but requires
more knowledge than we yet have. A major deficiency is the lack of well tested
models of and
sufficient data for exploited ecosystems. Developing workable models is the job of scientists and
can be achieved by a few, but obtaining good data requires a larger group. In the Vänern-
Klarälven ecosystem our understanding is best for the river part of the ecosyste
m. We also have
indirect measurements of survival of fish in the lake. Data collection fro
m Vänern could be
improved and a preliminary analysis of an ecosystem can be facilitated by scientists collaborat
ing
with resource users, who spend much time on the lake, and managing authorities. Fishers’
knowledge can be gathered through interviews and used to develop a preliminary understanding
of how the ecosystem is structured and functions (Olsson and Folke, 2001). Fishers can also be
engaged in a joint research program and can help to develop management policies, especially if
they are drawn into the scientific enterprise through workshops (Walters, 1986).
We propose that Vänern fishery is best documented and managed through co-
management. To do
this we need to understand that co-management means paying att
ention to what resource users
know and want. Here, it is important to establish a trusting relationship between authorities and
stakeholders, since fishermen who actively choose to work with scientists are motivated by the
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possibility of influencing and improving management, but there is also a fear that t
here might be
hidden agendas possessed by the authorities and that research results could be used against them
(Jacobsen et al., 2011). All stakeholders must be motivated to achieve sustainable management.
Achieving this will need models of the lake ecosystem that predict sustainable levels of fishing.
Sweden’s second largest lake, Vättern, could serve as an example with a well-established fisher
ies
co-management group acting as a working committee in the Lake Vättern Society for Water
Conservation, LVSWC (Stöhr et al., 2014). They take part in an participatory research project
bringing fishers, scientists and policy makers together to work towards sustainable fisheries for
the benefit of society (
http://gap2.eu/case-studies/case-stud y-6/
last accessed 26 September 2013
;
Mackinson et al., 2011; Jacobsen et al., 2011) which has been an important stimulus for the
introduction of co-management.
One way to convince fishers and other stakeholders that co-management is wort
h doing is to
involve them at ALL levels of the co-management process. The idea o
f participatory research in
Vänern is not new, there are some ongoing projects involving scientists and stakeholders, but
several earlier attempts have failed as a result of disagreements among stakeho
lders (pers. com.,
A. Sandström and M. Johansson, Institute of Freshwater Research, Drottningho
lm, Sweden).
However, the first steps towards co-management have already been taken by the County
Administrative Boards of Västra Götaland and Värmland, together with Vänerns
Vattenvårdsförbund.
A major problem influencing the success of the co-
management is the relationship between fisher,
scientist and manager. Traditionally, fishers have not been involved in data gather
ing and
management. Although some fishers in the last quarter of the 19
th
century raised the question o
f
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overfishing (Smith, 1994), they have become passive elements in the fishery and are manipulated
by a top-down management system. This has led to alienation of the fisher from the scientists and
managers, an alienation partly caused by the separation of intellectual outlook and training and
partly by the professionalization of science and management which leads to
institutional traditions
and methods that exclude those that are not members (Finlayson, 1994). True advances in
developing successful co-management will only be made once the fisher has accepted a ro
le as a
leader in setting the management goals. Persuading fishers to take this lead will be aided by
showing that sustainable exploitation has benefits for marketing the resource.
It is self-evident that a robust funding model must be developed if the co-
management approach is
to be implemented successfully. If the co-management inst
itution or consortium cannot guarantee
its own economic sustainability over the long term it will be difficult to attract stakeholders to
voluntarily take part in the process. Also, good monitoring and regular evaluat
ion of the
monitoring efforts and management constraints require long term funding. Previous efforts to
produce a fisheries management plan for Vänern have documented an existing set of interested
fishers, managing authorities and scientists willing to wor
k towards a co-management consortium,
but ultimately whether or not this set is supported financially is a political issue! Politicians and
decision makers have to be convinced that the ecosystem services provided by the lake are in
danger of being seriously damaged if their role is not well enough appreciated and managed. This
is an issue that concerns all who live in the Vänern catchment.
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ACCEPTED MANU SCRIPT ACCEPTED MANU SCRIPT 14 Conclusions
As ecosystem-based management is a possible way towards sustainability, co-
management seems to be a natural way to implement that. We identify four major barriers: (1)
ecosystem borders and state/county borders are rarely the same; (2) different stakeholders have
different needs and perspectives; (3) coordinating the monitoring that is needed for sa
lmonids
with their complex life cycle in a large ecosystem is difficult and expensive; (4) it is difficult to
attract adequate funding. We argue that by creating a Väner-Klarälven ecosystem management
consortium we have a better chance to overcome these barriers. In such a consortium scient
ists,
managers and stakeholders meet and work together. Through this process, not only can they better
coordinate research and management efforts, they can also better understand each other’s
perspectives and find acceptance for necessary trade-offs. Further, we
argue that by using Atlantic
Salmon and Brown Trout as example species we can show the full complexity of the pro
blem, as
these species need both river and lake habitat to complete their life cycle. Finally, we
hope that a
co-management group that clearly holds a holistic perspective will find it easier to gain public
support needed to attract the sustainable funding for ecosystem management.
Funding
We thank the European Union and the European regional development fund for
supporting the project Vänerlaxens fria gång
(S30441-48-10), Fortum Generation AB, Karlstad
University
and The County Administrative Board of Värmland for supporting different parts of the research
in Klarälven.
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ACCEPTED MANU SCRIPT ACCEPTED MANU SCRIPT 19 Figure 1.
Map of the catchment area of River Trysilälva and Klarälven. Hydro-e
lectric plants
(HEPs) are shown as bars.
25 km Lake Vänern Sweden Norway Klarälven Trysilelva Gullspångs älven Lake Femunden Lake Rogen Sweden Norway Baltic Sea North Sea
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ACCEPTED MANU SCRIPT ACCEPTED MANU SCRIPT 20 Figure 2.
Lake commercial catches (tonnes, bars), River returns (numbers, solid line), and Smo
lt stocking (numbers*10 -1
, broken line) of Atlantic Salmon and Brown Trout in Lake Vänern and
River Klarälven from 1809–2009. Data from: Nordberg (1977); Nilsson (1979); Piccolo et al.
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ACCEPTED MANU SCRIPT ACCEPTED MANU SCRIPT 21 Figure 3.
Number of returning wild Atlantic Salmon spawners to the fish tr
ap in Forshaga during
successive years.
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Citations (7) References (42)
... Currently, commercial and subsistence fishers are required to report harvest, but there are no fishing licence or reporting requirements whatsoever for the recreational fishery (Nilsson, 2014). Therefore, estimates of recreational fishing harvest of salmon and trout are highly uncertain, making it difficult to reconcile competing demands for recreational and commercial fisheries while improving wild stock conservation
(Bergman et al., 2014)
. Rough estimates from old provincial reports suggest total annual harvest from recreational fisheries varies from as low as 16 tonnes up to 88 tonnes of salmon and trout combined (Johansson and Andersson, 2011;Piccolo et al., 2012). ...
... Downstream passage of smolts and kelts is still unassisted, and recent studies suggest high mortality during downstream migration (Norrgård et al., 2013;Nyqvist et al., 2015). In addition to transporting wild spawners, compensatory stocking of hatchery-raised salmon and trout smolt began in the 1960s, and total catches have increased substantially since then (Piccolo et al. 2012;
Bergman et al., 2014
). An adipose-fin clipping program began in 1993 to distinguish between wild and hatchery fish, and all wild fish must be released, although no records of bycatch are available (Piccolo et al., 2012;Bergman et al., 2014). ...
... In addition to transporting wild spawners, compensatory stocking of hatchery-raised salmon and trout smolt began in the 1960s, and total catches have increased substantially since then (Piccolo et al. 2012;Bergman et al., 2014). An adipose-fin clipping program began in 1993 to distinguish between wild and hatchery fish, and all wild fish must be released, although no records of bycatch are available (Piccolo et al., 2012;
Bergman et al., 2014)
. The commercial, recreational and subsistence fisheries in the lake are all maintained by hatchery stocking, and every year some 250,000 finclipped salmon and trout smolt are released into the lake and its tributaries (Sandström et al., 2014). ...
Recreational trolling effort and catch of Atlantic salmon and brown trout in Vänern, the EU’s largest lake
Article Jul 2020 FISH RES Andersson A Larry Greenberg Eva Bergman John J Piccolo
Recreational fishing has grown substantially worldwide; for some recreational fisheries both catch and economic value now exceeds that of commercial fisheries. Monitoring of recreational fisheries effort and catch is therefore important for sustainable fisheries management. We developed and implemented an angler survey to estimate effort and catch for the recreational trolling fishery for landlocked Atlantic salmon (Salmo salar) and brown trout (S. trutta) in Lake Vänern, Sweden. Major challenges were the large spatial scale and dispersed fishing effort, a lack of revenue from fishing licence sales, and a lack of catch reporting requirements. We developed a complemented roving/mail-in survey to estimate effort and catch during the main fishing periods, spring and fall, 2014. Instantaneous counts from major access sites were used for effort estimates, and mail-in surveys were used for catch rates. Our results show that Vänern supports a salmon and trout fishery of some 28.7 ± 3.3 tonnes per year. Fishing effort was higher in the spring than in the fall, and there were seasonal differences in catch rates for trout but not for salmon. Estimates show that the recreational trolling fishery now harvests more salmon and trout annually than do the commercial and subsistence fisheries combined. This highlights the importance of continuing an angler survey program for Vänern as a key element for sustainable fisheries management, and can serve as a model for other recreational fisheries at large spatial scales.
View Show abstract
... For a large system where resources are limited, forming a partnership with the fishers who exploit the resource can be viewed as a process, focusing on joint learning and understanding how different management tasks are organized and solved and help in making sound scientific recommendations (Walters 1986). As a result, a formalized co-management organization, which includes stakeholders, managing authorities, and scientists, was initiated about 8 years ago
(Bergman et al. 2014)
. The group has been active, holding regularly scheduled meetings to discuss different issues involving salmon and trout. ...
Landlocked Salmon and Trout in the Lake Vänern-River Klarälven ecosystem – What can we do for the wild fish?
Conference Paper May 2018 Eva Bergman Olle Calles Larry Greenberg John J Piccolo View
... In addition, management actions are not being implemented for the full movement cycle. In the example of transporting salmon upstream by truck, no actions are being taken for the downstream migration of salmon, resulting in very low survival rates
(Bergman et al., 2014;
Hagelin et al., 2015). The recovery of this river's stock is therefore limited by not considering the migratory connectivity of both upstream and downstream migrations. ...
Linking Movement Ecology with Wildlife Management and Conservation
Article Full-text available Jan 2016 Andrew M. Allen Navinder J Singh
A common challenge in species conservation and management is how to incorporate species movements into management objectives. There often is a lack of knowledge of where, when and why species move. The field of movement ecology has grown rapidly in the last decade and is now providing the knowledge needed to incorporate movements of species into management planning. This knowledge can also be used to develop management strategies that are flexible in time and space and may improve the effectiveness of management actions. Therefore, wildlife management and conservation may benefit by strengthening the link with movement ecology. We present a framework that illustrates how animal movement can be used to enhance conservation planning and identify management actions that are complementary to existing strategies. The framework contains five steps that identify (1) the movement attributes of a species, (2) their impacts on ecosystems, (3) how this knowledge can be used to guide the scale and type of management, (4) the implementation, and (5) the evaluation of management actions. We discuss these five steps in detail, highlighting why the step is important and how the information can be obtained. We illustrate the framework through a case study of managing a highly mobile species, the Atlantic salmon (Salmo salar), a harvested species of conservation concern. We believe that the movement-management framework provides an important, and timely, link between movement ecology and wildlife management and conservation, and highlights the potential for complementary, dynamic solutions for managing wildlife.
View Show abstract
Lake survival of hatchery‐reared adfluvial brown trout—A case study in a large natural lake in Sweden
Article Mar 2024 Daniel Palm Petter Lundberg Lo Persson Gustav Hellström
Throughout their native range, adfluvial brown trout populations have declined due to habitat degradation and over exploitation. As a consequence, numerous restoration projects that include stocking of hatchery‐reared trout have been conducted; however, estimates of survival in large lakes remain scarce. Here, we use telemetry to evaluate the survival of stocked trout smolts and sub‐adults in a large lake in central Sweden. Of the smolts released in the main tributary, 42% entered the lake. Both life stages suffered high rates of mortality. Only 8% of smolts survived the first 10 months after entering the lake and 10% of those released as sub‐adults survived 23 months post‐release. In agreement with studies on anadromous trout, we conclude that stocking of hatchery‐reared individuals is not an efficient method to recover population numbers due to poor performance in the wild. Similar studies from other large lakes and comparisons with wild conspecifics would increase the applicability of the results and promote further understanding of the utilization of hatchery‐origin trout to rebuild wild populations and sustain fisheries.
View Show abstract
Landlocked Atlantic salmon in a large river-lake ecosystem: managing an endemic, large-bodied population of high conservation value
Article Dec 2020 Larry Greenberg Johnny R Norrgård Pär Gustafsson Eva Bergman
Managing and conserving threatened migratory salmonid populations in large river-lake ecosystems is challenging not only because of the ecosystems’ large size, but also because there is often more than one anthropomorphic stressor. The River Klarälven-Lake Vänern ecosystem, situated in Norway and Sweden, is a large highly modified ecosystem, home to a threatened, endemic, large-bodied population of landlocked salmon. With 11 dams, the salmon population has been maintained through extensive stocking and a truck and transport system for spawners. Here we review what we have learned about the salmon after 15 years of research, highlighting the major findings for each life stage. Our studies indicate that the salmon population is below carrying capacity, and we suggest measures to increase the number of spawners and downstream passage success. Habitat restoration to compensate for losses from former log driving activities is expected to further increase carrying capacity. Re-establishing salmon in Klarälven’s upper reaches in Norway, while possible, is fraught with both ecological and legislative hurdles. Substantial long-term funding is needed to foster co-management and ensure a sustainable fishery.
View Show abstract
Life-History Variability and Conservation Status of Landlocked Atlantic Salmon: An Overview
Article Full-text available Mar 2019 Jeffrey A Hutchings William R. Ardren Bjørn Barlaup Dylan J. Fraser
Non-anadromous Atlantic salmon (Salmo salar) exhibit a combination of variation in life history, habitat, and species co-existence matched by few vertebrates. Distributed in eastern North America and northern Europe, habitat ranges from hundreds of metres of river to Europe’s largest lakes. As juveniles, those with access to a lake usually migrate to feed and grow prior to reproduction. Prey such as smelt (Osmerus mordax, O. eperlanus) and vendace (Coregonus albula) facilitate large body size (50-85cm at maturity) and persistence in high-diversity (>20 fish species) environments; small-bodied salmon (10-30cm at maturity), relying on insects as prey, coexist with few (<5) other fishes. At maturity, weight varies more than 400-fold (17 to 7200 g) among populations, fecundity more than 150-fold (33 to 5600), and longevity almost 5-fold (3 to 14 yr). Landlocked salmon are managed to support sustainable fishing, achieve conservation/restoration targets, and mitigate threats; successes are evident but multiple challenges persist. Extraordinary variability in life history coupled with extensive breadth of habitat and species co-existence render landlocked Atlantic salmon singularly impressive from a biodiversity perspective.
View Show abstract
Ecosystem health of Lake Vänern: Past, present and future research
Article Apr 2015 G. Dave M. Munawar Sten-Åke Wängberg
The large lakes of Sweden (Vänern, Vättern, Mälaren and Hjälmaren) have been monitored for more than four decades for water quality conditions to assess the impact of eutrophication from anthropogenic activities. Lake Vänern is basically an oligotrophic lake that showed signs of eutrophication, notably the emergence of algal blooms in the coastal areas (1967–1968). The lake was also contaminated, due to the discharge of pulp and paper effluents including metals such as mercury. However, ecosystem-based information is lacking for Lake Vänern. Consequently a symposium was organized in 2012 by the University of Gothenburg, Mötesplats Vänersborg and the Aquatic Ecosystem Health and Management Society to: assess the current status of the health of Lake Vänern's ecosystem, identify knowledge gaps and develop a road map for the future. In this regard, Lake Vänern was compared with the North American Great Lakes to learn from their extensive, long-term data sets. A special issue devoted to the “State of Lake Vänern Ecosystem” symposium was published in Aquatic Ecosystem Health and Management (AEHM, Vol. 17, no. 4) including keynotes and contributed papers. The conclusions shown in the appendix (available in the online supplementary information) summarize the authors' contributions. Most of the articles covered Lake Vänern, but some were directed towards monitoring and management of Great Lakes in general, and others addressed co-operation under the auspices of international agreements and directives. Based on the background information provided by the State of Lake Vänern Ecosystem symposium and its publication in the special issue, the conveners decided that a synthesis of the symposium with recommendations for the future would be useful in boosting ecosystem research in Lake Vänern.
View Show abstract
Reconnecting Social and Ecological Resilience in Salmon Ecosystems
Article Full-text available Jan 2009 ECOL SOC Daniel Bottom Kim K. Jones Charles Simenstad Courtland L. Smith
Fishery management programs designed to control Pacific salmon (Oncorhynchus spp.) for optimum production have failed to prevent widespread fish population decline and have caused greater uncertainty for salmon, their ecosystems, and the people who depend upon them. In this special feature introduction, we explore several key attributes of ecosystem resilience that have been overlooked by traditional salmon management approaches. The dynamics of salmon ecosystems involve social-ecological interactions across multiple scales that create difficult mismatches with the many jurisdictions that manage fisheries and other natural resources. Of particular importance to ecosystem resilience are large-scale shifts in oceanic and climatic regimes or in global economic conditions that unpredictably alter social and ecological systems. Past management actions that did not account for such changes have undermined salmon population resilience and increased the risk of irreversible regime shifts in salmon ecosystems. Because salmon convey important provisioning, cultural, and supporting services to their local watersheds, widespread population decline has undermined both human well-being and ecosystem resilience. Strengthening resilience will require expanding habitat opportunities for salmon populations to express their maximum life-history variation. Such actions also may benefit the "response diversity" of local communities by expanding the opportunities for people to express diverse social and economic values. Reestablishing social-ecological connections in salmon ecosystems will provide important ecosystem services, including those that depend on clean water, ample stream flows, functional wetlands and floodplains, intact riparian systems, and abundant fish populations.
View Show abstract
Four decades of research on the Swedish large lakes Malaren, Hjalmaren, Vattern and Vanern: The significance of monitoring and remedial measures for a sustainable society
Article Full-text available Dec 2001 Eva Willén
The large lakes of Sweden, Malaren, Hjalmaren, Vattern and Vanern, have been subjected to water-quality monitoring for almost four decades. Physicochemical variables, plankton and benthic invertebrates have been regularly assessed. Hydrological and sediment conditions, macrophytes, fish, primary production, bacteria and attached algae have been periodically investigated. The human impact, including industrial activities, was reflected in excessive amounts of organic matter, nutrients, metals and persistent organic compounds. From the late 1960s all municipal sewage works in the catchments of the lakes were upgraded to the highest technical standard, including chemical precipitation of phosphorus, and phosphorus discharge from the sewage works was thereby reduced by 90-95%. In addition, industries were obliged to restrict discharge of harmful substances. The reactions of the lakes to the remedial measures are discussed as well as the value of various indicators. The studies were instrumental in designing a national lake monitoring program. Additionally, results from large lake monitoring have contributed to the establishment of national water-quality criteria including, physical, chemical, and biological indicators.
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Why aren't there more Atlantic salmon (Salmo salar)?
Article Full-text available Jan 1998 Donna Parrish Robert J Behnke Stephen R Gephard Gordon H Reeves
Numbers of wild anadromous Atlantic salmon (Salmo salar) have declined demonstrably throughout their native range. The current status of runs on rivers historically supporting salmon indicate widespread declines and extirpations in Europe and North America primarily in southern portions of the range. Many of these declines or extirpations can be attributed to the construction of mainstem dams, pollution (including acid rain), and total dewatering of streams. Purported effects on declines during the 1960s through the 1990s include overfishing, and more recently, changing ocean conditions, and intensive aquaculture. Most factors affecting salmon numbers do not act singly, but rather in concert, which masks the relative contribution of each factor. Salmon researchers and managers should not look for a single culprit in declining numbers of salmon, but rather, seek solutions through rigorous data gathering and testing of multiple effects integrated across space and time.
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Stakeholder participation and sustainable fisheries: An integrative framework for assessing adaptive comanagement processes
Article Full-text available Aug 2014 ECOL SOC Christian Stöhr Cecilia Lundholm Beatrice Crona Ilan Chabay
Adaptive comanagement (ACM) has been suggested as the way to successfully achieve sustainable environmental governance. Despite excellent research, the field still suffers from underdeveloped frameworks of causality. To address this issue, we suggest a framework that integrates the structural frame of Plummer and Fitzgibbons’ “adaptive comanagement” with the specific process characteristics of Senecah’s “Trinity of Voice.” The resulting conceptual hybrid is used to guide the comparison of two cases of stakeholder participation in fisheries management—the Swedish Co-management Initiative and the Polish Fisheries Roundtable. We examine how different components of preconditions and the process led to the observed outcomes. The analysis shows that despite the different cultural and ecological contexts, the cases developed similar results. Triggered by a crisis, the participating stakeholders were successful in developing trust and better communication and enhanced learning. This can be traced back to a combination of respected leadership, skilled mediation, and a strong focus on deliberative approaches and the creation of respectful dialogue. We also discuss the difficulties of integrating outcomes of the work of such initiatives into the actual decision-making process. Finally, we specify the lessons learned for the cases and the benefits of applying our integrated framework.
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Trout and Salmon of North America
Book Jan 2002 Robert J Behnke View
Bioeconomics and the Management of Renewable Resources
Chapter Jan 1986 Jon M Conrad
Within the past decade many economists have become interested in natural resource models which simultaneously consider economic flows (such as cost and revenue) and population dynamics. Resource management is often cast as a problem in dynamic optimization where the management objective may be to maximize the present value of net benefits subject to the stock adjustments which result from growth, natural mortality, and man’s harvesting activities. When the resource in question is a plant or animal, capable of regeneration, these resource models are called bioeconomic models.
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Ecosystem-Based Fisheries Management: Confronting Tradeoffs
Article Jan 2010 Jason S Link
Responsible fisheries management is of increasing interest to the scientific community, resource managers, policy makers, stakeholders and the general public. Focusing solely on managing one species of fish stock at a time has become less of a viable option in addressing the problem. Incorporating more holistic considerations into fisheries management by addressing the trade-offs among the range of issues involved, such as ecological principles, legal mandates and the interests of stakeholders, will hopefully challenge and shift the perception that doing ecosystem-based fisheries management is unfeasible. Demonstrating that EBFM is in fact feasible will have widespread impact, both in US and international waters. Using case studies, underlying philosophies and analytical approaches, this book brings together a range of interdisciplinary topics surrounding EBFM and considers these simultaneously, with an aim to provide tools for successful implementation and to further the debate on EBFM, ultimately hoping to foster enhanced living marine resource management.
View Show abstract Co-management-the way forward Article Jan 2003 Svein Jentoft View
Scaling Fisheries: The Science of Measuring the Effects of Fishing, 1855-1955.
Article Aug 1995 D. B. Sampson Tim Smith View Fisheries Ecology Article Feb 1983
R. H. K. Mann
Tony J. Pitcher
P. J. B. Hart
View Show more Recommended publications Discover more about: Atlantic Salmon Article Full-text available
Choice experiment assessment of anglers’ salmonid conservation preferences
June 2019 ·
Journal of Environmental Planning and Management
Gianluca Grilli John Curtis
Wild Atlantic salmon and sea trout are in danger in several fisheries of the northern hemisphere due to anthropic activities. The pressures on fish stocks include excessive commercial and recreational harvests, as well as habitat depletion. In this paper, we present a choice experiment assessment of recreational anglers’ preferences for conservation options, aiming to reduce harvest and improve
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ecosystem quality of salmon fisheries using Ireland as a case study. Data were collected by online survey and analysed with a latent class logit model. Results indicate two groups of anglers with diverging opinions and preferences on salmon conservation priorities, which will likely be reflected in different levels of acceptance of conservation initiatives.
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The value of in-stream water temperature forecasts for fisheries management
April 2012 · Contemporary Economic Policy BIAO HUANG Christian Langpap Richard M. Adams
Water temperature is an important factor affecting aquatic life within the stream environment. Cold water species, such as salmonids, are particularly susceptible to elevated water temperatures. This paper examines the economic value of short‐term water temperature forecasts for salmonid management. Forecasts may have economic value if they allow the water resource manager to make better water
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allocation decisions. This study considers two applications: water releases for management of Chinook salmon in the Klamath River and leasing water from agriculture for management of steelhead trout in the John Day River. We incorporate biophysical models and water temperature distribution data into a Bayesian framework to simulate changes in fish populations and the corresponding benefit from recreational fishing and opportunity cost of water under different temperature forecast accuracies. Simulation results indicate that use of the forecasts results in increased fish production and that marginal costs decline and net benefits increase as forecast accuracy increases, suggesting that provision and use of such stream temperature forecasts would have value to society.
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Recreational trolling effort and catch of Atlantic salmon and brown trout in Vänern, the EU’s larges...
July 2020 · Fisheries Research Andersson A Larry Greenberg Eva Bergman [...] John J Piccolo
Recreational fishing has grown substantially worldwide; for some recreational fisheries both catch and economic value now exceeds that of commercial fisheries. Monitoring of recreational fisheries effort and catch is therefore important for sustainable fisheries management. We developed and implemented an angler survey to estimate effort and catch for the recreational trolling fishery for
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landlocked Atlantic salmon (Salmo salar) and brown trout (S. trutta) in Lake Vänern, Sweden. Major challenges were the large spatial scale and dispersed fishing effort, a lack of revenue from fishing licence sales, and a lack of catch reporting requirements. We developed a complemented roving/mail-in survey to estimate effort and catch during the main fishing periods, spring and fall, 2014. Instantaneous counts from major access sites were used for effort estimates, and mail-in surveys were used for catch rates. Our results show that Vänern supports a salmon and trout fishery of some 28.7 ± 3.3 tonnes per year. Fishing effort was higher in the spring than in the fall, and there were seasonal differences in catch rates for trout but not for salmon. Estimates show that the recreational trolling fishery now harvests more salmon and trout annually than do the commercial and subsistence fisheries combined. This highlights the importance of continuing an angler survey program for Vänern as a key element for sustainable fisheries management, and can serve as a model for other recreational fisheries at large spatial scales.
Read more Chapter Aquaculture June 2019 Pete Minard
This chapter covers colonial aquaculture in 1860s Victoria with emphasis on the Atlantic Salmon and Brown Trout. The ASV program observed important factors regarding the development of salmonid aquaculture in North America such as the relationship between recreational and commercial fishing, discussion about the placement of certain species, and ways in which damaged fisheries can be restored.
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Overall, this chapter explores the re-examination of aquaculture due to the failure of salmon acclimatization.
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