scholarly journals Comparative evaluation of a mixed-fisheries effort-management system based on the Faroe Islands example

2010 ◽  
Vol 67 (5) ◽  
pp. 1036-1050 ◽  
Author(s):  
Alan Baudron ◽  
Clara Ulrich ◽  
J. Rasmus Nielsen ◽  
Jesper Boje
Keyword(s):  
Management System ◽  
Comparative Evaluation ◽  
Gadus Morhua ◽  
Evaluation Model ◽  
Regulation System ◽  
Melanogrammus Aeglefinus ◽  
Faroe Islands ◽  
Total Allowable Catch ◽  
Strategy Evaluation ◽  
Short And Long Term

AbstractBaudron, A., Ulrich, C., Nielsen, J. R., and Boje, J. 2010. Comparative evaluation of a mixed-fisheries effort-management system based on the Faroe Islands example. – ICES Journal of Marine Science, 67: 1036–1050. Total allowable catch (TAC) management has in many fisheries, especially mixed fisheries, failed to meet conservation objectives. For instance, for the Faroe Plateau mixed demersal fisheries, the TAC system failed to achieve the objective of an average annual fishing mortality of 0.45 for the three gadoid stocks cod (Gadus morhua), haddock (Melanogrammus aeglefinus), and saithe (Pollachius virens). Therefore, in 1996, an effort-regulation system with individual transferable effort quotas was introduced to manage the fisheries. Experience has shown that effort management without additional stock-specific measures may not be appropriate for such fisheries. A management strategy evaluation model was developed to compare an effort-management system based on the Faroese example with a TAC system as currently applied in EU fisheries. Results show that when stocks are considered in isolation, a total allowable effort system does not necessarily perform better than a TAC one. It depends on stock status and dynamics, the level of uncertainty, and the reactivity of the system to changes in scientific advice. When the stocks are considered together in mixed fisheries, effort management seems, however, to be appropriate, and interannual flexibility of the system appears to be the best compromise between short- and long-term objectives, as well as between biological sustainability and economic return.

Fishing power increases from technological development in the Faroe Islands longline fishery

2011 ◽  
Vol 68 (11) ◽  
pp. 1970-1982 ◽  
Author(s):  
Ole Ritzau Eigaard ◽  
Bjarti Thomsen ◽  
Holger Hovgaard ◽  
Anders Nielsen ◽  
Adriaan D. Rijnsdorp
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Technological Development ◽  
Melanogrammus Aeglefinus ◽  
Faroe Islands ◽  
Longline Fishery ◽  
Catch Per Unit Effort ◽  
Total Allowable Catch ◽  
Input Control ◽  
Generalized Linear Modelling

During an effort-regulated period from 1996 to 2002, unregistered annual increases of 0.3% of hooks fished per day were demonstrated for the Faroe Islands longline fishery. However, annual increases were higher (1.5%) during a preceding total allowable catch regulated period, thereby invalidating an expectation of the 1996 shift in regulations (output to input control) to have induced increases in the number of hooks set per day. Underlying this result is a substantial increase in total yearly effort (fishing days) and a shift in targeting behaviour from secondary to primary (high value) target species in response to the transition from output to input control. Interview data on technology were combined with logbook data and analysed with generalized linear modelling to demonstrate haddock ( Melanogrammus aeglefinus ) and Atlantic cod ( Gadus morhua ) catch-per-unit-effort increases of 51% and 26%, respectively, following the introduction of skewed hooks and swivel line. The technological introductions were not correlated to regulation shifts. So, rather than the management system in force, an ongoing technological development seems to be the principal driver of fishing power trends. The results highlight the need to explicitly address technological development and targeting behaviour when attempting to meet conservation objectives through input control of fisheries.

scholarly journals Penalties and rewards for over- and underages of catch allocations

2008 ◽  
Vol 65 (9) ◽  
pp. 1541-1551 ◽  
Author(s):  
Joseph E. Powers ◽  
Elizabeth N. Brooks
Keyword(s):  
Decision Rules ◽  
Temporal Distribution ◽  
Evaluation Framework ◽  
Total Allowable Catch ◽  
Strategy Evaluation ◽  
User Groups ◽  
Short And Long Term ◽  
Spatio Temporal ◽  
Monitoring Precision ◽  
Time Frames

Abstract Powers, J. E., and Brooks, E. N. 2008. Penalties and rewards for over- and underages of catch allocations. – ICES Journal of Marine Science, 65: 1541–1551. Many fisheries are managed using a total allowable catch (TAC) that is subsequently sub-allocated to different fisheries sectors. These allocations are then monitored separately to ensure the adherence of each fishery to its particular allocation quota and to the overall TAC. In some management arenas, there are systems of “payback” where over- and underages are punished or rewarded using particular decision rules. Differences between fishing gear, the sizes and ages of fish being targeted by those gears, and the spatio-temporal distribution of the fishers using those gears can lead to different precision, accuracy, and cost of monitoring the allocation, affecting the probability that an overall management objective is reached. Weaknesses in monitoring may be exploited by user groups in their competition for larger catches and, subsequently, bigger allocations, so differential monitoring precision and accuracy can lead to both short- and long-term reallocations, i.e. a new set of winners and losers. Simulations in a management strategy evaluation framework were used to demonstrate the implications of alternative decision rules regarding payback on conservation and sustainability objectives and rebuilding time frames. The efficacy of the rules under alternative monitoring systems was also examined. Decision rules allowing payback prolong rebuilding (compared with perfect implementation or more precautionary TACs), especially if monitoring is biased (catches misreported) or imprecise. When precision of reported catches was increased and/or bias decreased, better yields and stock abundance resulted. When overages were penalized and underages not rewarded, recovery was achieved earlier. Conversely, policies in which transgressions were ignored and underages rewarded did not perform well. Underreporting by one nation may result in stocks that are well below the stock size conservation standards, yet produce substantial gains in yield for that nation, unless other nations retaliate by underreporting.

scholarly journals Fully documented fishery: a tool to support a catch quota management system

2011 ◽  
Vol 68 (8) ◽  
pp. 1606-1610 ◽  
Author(s):  
Lotte Kindt-Larsen ◽  
Eskild Kirkegaard ◽  
Jørgen Dalskov
Keyword(s):  
Management System ◽  
Gadus Morhua ◽  
Electronic Monitoring ◽  
Scientific Advice ◽  
Total Catch ◽  
Total Allowable Catch ◽  
International Council ◽  
Fishing Vessels ◽  
Scientific Advisory ◽  
Quota Management

Abstract Kindt-Larsen, L., Kirkegaard, E., and Dalskov, J. 2011. Fully documented fishery: a tool to support a catch quota management system. – ICES Journal of Marine Science, 68: 1606–1610. The Danish Government has proposed a catch quota management system (CQMS) in which fishers are obliged to report their total catches, including discards and landings, and both are counted against the formal total allowable catch (TAC). The success of a CQMS requires appropriate documentation to verify the total catch, the validity of scientific advice, and the implementation of the TACs through national catch quotas. A remote electronic monitoring (EM) system, providing full documentation of fishing operations and catches, was tested on six Danish fishing vessels operating under a CQMS for cod (Gadus morhua). The results showed that the EM system could provide the documentation required to support the CQMS and that it was an incentive for the participating fishers to avoid discarding cod. Changing from landings to total catch quotas would not affect the scientific-advisory processes of the International Council for the Exploration of the Sea (ICES), but it could have notable consequences for the allocation of TACs between countries.

Parasites as biological tags in marine fisheries research: European Atlantic waters

Parasitology ◽  
2014 ◽  
Vol 142 (1) ◽  
pp. 54-67 ◽  
Author(s):  
K. MACKENZIE ◽  
W. HEMMINGSEN
Keyword(s):  
Marine Mammals ◽  
Gadus Morhua ◽  
Clupea Harengus ◽  
Melanogrammus Aeglefinus ◽  
Ecological Group ◽  
The North ◽  
Recent Developments ◽  
Host Parasite ◽  
Mediterranean And Black Seas ◽  
Biological Tags

SUMMARYStudies of the use of parasites as biological tags for stock identification and to follow migrations of marine fish, mammals and invertebrates in European Atlantic waters are critically reviewed and evaluated. The region covered includes the North, Baltic, Barents and White Seas plus Icelandic waters, but excludes the Mediterranean and Black Seas. Each fish species or ecological group of species is treated separately. More parasite tag studies have been carried out on Atlantic herring Clupea harengus than on any other species, while cod Gadus morhua have also been the subject of many studies. Other species that have been the subjects of more than one study are: blue whiting Micromesistius poutassou, whiting Merlangius merlangus, haddock Melanogrammus aeglefinus, Norway pout Trisopterus esmarkii, horse mackerel Trachurus trachurus and mackerel Scomber scombrus. Other species are dealt with under the general headings redfishes, flatfish, tunas, anadromous fish, elasmobranchs, marine mammals and invertebrates. A final section highlights how parasites can be, and have been, misused as biological tags, and how this can be avoided. It also reviews recent developments in methodology and parasite genetics, considers the potential effects of climate change on the distributions of both hosts and parasites, and suggests host-parasite systems that should reward further research.

Effects of sex, stock, and environment on the shape of known-age Atlantic cod (Gadus morhua) otoliths

2004 ◽  
Vol 61 (2) ◽  
pp. 158-167 ◽  
Author(s):  
M Cardinale ◽  
P Doering-Arjes ◽  
M Kastowsky ◽  
H Mosegaard
Keyword(s):  
Shape Analysis ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Fourier Descriptors ◽  
Faroe Islands ◽  
Stock Identification ◽  
Relative Importance ◽  
Age Classes ◽  
Otolith Shape ◽  
Left And Right

The effects of sex, stock, and environment on the shape of known-age Atlantic cod (Gadus morhua) otoliths from the Faroe Islands were investigated. Moreover, the feasibility of otolith shape analysis for stock identification was evaluated. The shape was described by using several normalized Fourier descriptors and morphometric variables. There were no consistent differences between the left and right otoliths and between sexes within different age classes, stocks, and environments. With our experimental design, we could evaluate the relative importance of genetic and environmental conditions (water temperature and diet regime) on otolith shape and morphometrics. Using otolith shape, cod individuals were significantly separated into Bank and Plateau stocks. Total classification success was between 79% and 85% between stocks and between 85% and 96% between environments for the different age classes. The significant differences in otolith shape between Faroe Bank and Faroe Plateau cod stocks provided a phenotypic basis for stock separation. Stock and environmental influences were substantial in determining the shape of cod otoliths.

scholarly journals Population dynamics of two sympatric intertidal fish species (the shanny, Lipophrys pholis and long-spined scorpion fish, Taurulus bubalis) of Great Britain

2016 ◽  
Vol 98 (3) ◽  
pp. 589-595 ◽  
Author(s):  
C.J. Barrett ◽  
M.L. Johnson ◽  
S.L. Hull
Keyword(s):  
Population Dynamics ◽  
Great Britain ◽  
Fish Species ◽  
Gadus Morhua ◽  
Sympatric Species ◽  
Rocky Intertidal ◽  
Melanogrammus Aeglefinus ◽  
Intertidal Zones ◽  
Spatio Temporal ◽  
Scorpion Fish

The shanny/common blenny (Lipophrys pholis) and long-spined scorpionfish/bullhead (Taurulus bubalis) are commonly encountered, sympatric species within much of Great Britain's rocky intertidal zones. Despite being prey items of the cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) respectively, and both contributors to the diet of the near-threatened European otter (Lutra lutra), little is known on the population dynamics of the temperate specimens of Great Britain. It is further less known of the degrees of sympatricity between the two fish species and to what extent they are able to coexist. The current study examines spatio-temporal distributions and abundances at various resolutions: monthly population dynamics of both species along England's Yorkshire coast and seasonal population dynamics along the Yorkshire coast and around the Isle of Anglesey, Wales. Studies of their abundances, sizes, degrees of rock pool co-occurrence and diel activities are further examined, which indicate coexistence is maintained when interspecific co-occurrence takes place only between specimens of similar sizes, thus demoting size-related dominance hierarchies.

Species specific behaviour and catchability of gadoid fish to floated and bottom set pots

2016 ◽  
Vol 74 (3) ◽  
pp. 769-779 ◽  
Author(s):  
Neil Anders ◽  
Anders Fernö ◽  
Odd-Børre Humborstad ◽  
Svein Løkkeborg ◽  
Anne Christine Utne-Palm
Keyword(s):  
Water Column ◽  
Gadus Morhua ◽  
Capture Efficiency ◽  
Escape Rate ◽  
Melanogrammus Aeglefinus ◽  
Encounter Rate ◽  
Specific Behaviour ◽  
Upstream Direction ◽  
Species Specific ◽  
Specific Food

To increase our understanding of the interaction between fish and baited fishing gear we quantitatively described the behaviour of cod (Gadus morhua), saithe (Pollachius virens), and haddock (Melanogrammus aeglefinus) to baited pots in a fjord in northern Norway. Detailed video analyses were made to describe species specific responses and examine the effect of lifting the pot off the bottom. The majority of both cod and saithe approached the pots in an upstream direction, and fish approached floated pots higher in the water column than bottom set pots. Cod tended to approach a pot along the seabed and were more likely to encounter the bottom set pot than the floated pot, whereas saithe more often approached in the water column. The capture efficiency was low for all species, but cod were more likely to be caught than saithe and haddock. Cod showed a high encounter rate, low entrance rate and high escape rate. For saithe, a low encounter rate was the chief factor limiting capture efficiency. The observed differences between cod and saithe were explained by species-specific food-search strategies. No difference in entrance rate, escape rate or catch efficiency between the two pot types were found.

scholarly journals Documentation of multiple species of marine fish trapped in Atlantic salmon sea-cages in Norway

2018 ◽  
Vol 31 ◽  
pp. 31
Author(s):  
Per Gunnar Fjelldal ◽  
Monica F. Solberg ◽  
Kevin A. Glover ◽  
Ole Folkedal ◽  
Jonatan Nilsson ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Salmo Trutta ◽  
Gadus Morhua ◽  
Mesh Size ◽  
Anguilla Anguilla ◽  
Wild Fish ◽  
Melanogrammus Aeglefinus ◽  
European Eel ◽  
Farmed Salmon ◽  
Sea Trout

The production of salmonids in sea-cages has been developed for monoculture of the target species. However, we show here for the first time, that wild fish may enter sea-cages used for farming of Atlantic salmon (Salmo salar L.) in Norway, out-grow the mesh size, and thereafter become permanently trapped. Within seven different sea-cages located in western Norway, eight different species of wild fish were identified; European eel (Anguilla anguilla), sea trout (Salmo trutta L.), cod (Gadus morhua), haddock (Melanogrammus aeglefinus), saithe (Pollachius virens), pollack (Pollachius pollachius), hake (Merluccius merluccius) and whiting (Merlangius merlangus). In the two most extreme cases, a 5 × 5 × 7 m cage with 311 farmed salmon (903 g) also contained 542 whiting (79 g), 77 haddock (43 g), and 5 cod (26 g), and a 12 × 12 × 15 m cage with 1695 farmed salmon (559 g) also contained 1196 haddock (35 g), 1115 whiting (31 g), 46 cod (23 g), 23 saithe (48 g), 15 pollock (22 g), 5 sea trout (54 g), and 2 hake (29 g). The present study thus demonstrates that aquaculture cages designed for monoculture may attract and effectively ‘trap’ wild fish. We did not investigate the frequency of this occurrence, and the ecological significance of these observations remains unclear. However, with the ever-increasing number of sea-cages used for global aquaculture, this is clearly a topic for further research.

Recent Growth, Biochemical Composition and Prey Field of Larval Haddock (Melanogrammus aeglefinus) and Atlantic Cod (Gadus morhua) on Georges Bank

1987 ◽  
Vol 44 (1) ◽  
pp. 14-25 ◽  
Author(s):  
L. J. Buckley ◽  
R. G. Lough
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Dry Weight ◽  
Melanogrammus Aeglefinus ◽  
Good Growth ◽  
Georges Bank ◽  
Larval Population ◽  
Prey Biomass ◽  
Recent Growth ◽  
Haddock Melanogrammus Aeglefinus

A transect across southern Georges Bank in May 1983 showed higher levels of available prey for haddock (Melanogrammus aeglefinus) and cod (Gadus morhua) larvae at two stratified sites than at a well-mixed site. At the stratified sites, prey biomass was high (30–300 μg dry wt∙L−1) near the surface above the thermocline; values were lower and more uniform with depth (10–30 μg dry wt∙L−1) at the well-mixed site. Larval population centers generally coincided with prey biomass vertically. Recent growth in dry weight of haddock larvae as estimated by RNA–DNA ratio analysis was higher at the stratified sites (8–13%∙d−1) than at the well-mixed site (7%∙d−1). Larvae appeared to be in excellent condition at the stratified sites, but up to 50% of haddock larvae from the well-mixed site had RNA–DNA ratios in the range observed for starved larvae in the laboratory. Cod collected at the same site were in better condition and growing faster than haddock. The data support the hypotheses that (1) stratified conditions in the spring favor good growth and survival of haddock larvae and (2) cod larvae are better adapted to grow and survive in well-mixed waters at lower levels of available food than haddock larvae.

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