| 1. |
|
|
| 2. |
- Bryhn, Andreas, et al.
(författare)
-
Kunskapsunderlag om möjliga icke-torskfiskerelaterade åtgärder för att torskbestånd ska bevaras och återhämta sig i svenska vatten
- 2020
-
Rapport (refereegranskat)abstract
- Torsk (Gadus morhua) är en viktig art för marina ekosystem i Sverige, där den har en strukturerande och reglerande funktion i relation till andra arter. Torsken har under historiens gång även spelat en viktig roll för samhället i Sverige inom dess nuvarande gränsers område (Bohuslän har t.ex. inte alltid tillhört Sverige), som en målart för fiske. Samtliga torskbestånd som återfinns i havsområdena runt Sverige har nu dålig status och det internationella havsforskningsrådet ICES rekommenderar låg eller ingen fångst, beroende på bestånd. Utöver riktat fiske påverkas dock torsken av en rad andra faktorer som exempelvis bifångster i annat fiske, syrebrist, klimatförändringar, predatorer, parasiter, bottenpåverkan av trålning, förlust av uppväxtmiljöer, födobrist, tiaminbrist och giftiga ämnen. Denna rapport diskuterar möjligheter att skydda och bevara torsken på sätt som kan komplettera begränsningar i det riktade torskfisket. Torskens situation är komplex och rapporten är därför skriven utifrån ett ekosystemperspektiv för att möjliggöra en bredare ansats i förvaltningen av torskbestånd i svenska vatten, där alla relevanta påverkansfaktorer bör beaktas. Det bör poängteras att denna rapport inte har gjort någon ny utredning av påverkansfaktorernas effekter, utan har istället gjort en litteratursammanställning och en kvalitativ analys. Vi har ändå valt att lyfta fram vissa åtgärder som särskilt potentiellt betydelsefulla - en samlad kvalitativ expertbedömning som rangordnar olika åtgärders effektivitet för återuppbyggnad per bestånd, se avsnitt 6 i rapporten.
|
|
| 3. |
- Bryhn, Andreas, et al.
(författare)
-
Which factors can affect the productivity and dynamics of cod stocks in the Baltic Sea, Kattegat and Skagerrak?
- 2022
-
Ingår i: Ocean and Coastal Management. - : Elsevier BV. - 0964-5691 .- 1873-524X. ; 223
-
Forskningsöversikt (refereegranskat)abstract
- Stocks of Atlantic cod (Gadus morhua) in the Baltic Sea, Kattegat and Skagerrak (N. Europe) have been strongly exploited for decades bringing them into an enduringly depleted status. Scientific cod stock related advice for targeted and mixed fisheries is provided on an annual basis by the International Council for Exploration of the Sea. This advice forms a basis for ministerial decisions on, e.g., the total allowable catch and management plans. Despite measures to reduce fishing-induced mortality of cod, such as catch and effort restrictions, increased gear selectivity, closed areas and seasons, clear signs of recovery are yet to be seen. Thus, traditional advice for the management of these stocks may have to be complemented by advice on supporting measures focusing on other pressures hampering the recovery of cod. The present study elaborates on potential supportive measures for cod stock recovery in the Baltic Sea, Kattegat, and Skagerrak (including local populations where applicable), based on current knowledge. The list of measures presented here is the outcome of in-depth discussions on the state-of-the-art knowledge, among cod experts and further with stakeholders with the aim to follow principles of ecosystem-based fisheries management. Following the identification of different pressures on and prerequisites for the separate stocks, the listed measures differ between stocks and include cod bycatch mortality reduction, alterations in fisheries affecting food sources for cod, restocking, protection of juvenile habitats, and reduced predation. The literature review and the list of measures are intended to provide decision-support for managers and policymakers aiming to provide conditions for the cod stocks to recover.
|
|
| 4. |
- Andersson, Magnus, et al.
(författare)
-
Fiskbestånd och miljö i hav och sötvatten : Resurs- och miljööversikt 2012
- 2012
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Detta är den nionde utgåvan av den samlade översikten över fisk- och kräftdjursbeståndens status i våra vatten. Kunskap om fiskbestånden och miljön är en förutsättning för att utnyttjandet av fiskresurserna skall bli bärkraftigt. För svenska vattenområden beskrivs miljöutvecklingen i ett ekosystemsperspektiv, dels för att tydliggöra fiskens ekologiska roll och beskriva yttre miljöfaktorer som påverkar fiskbestånden, dels för att belysa fiskets effekter på miljön.Fiskbestånd och miljö i hav och sötvatten är utarbetad av Sveriges lantbruksuniversitet (SLU), Institutionen för akvatiska resurser (SLU Aqua), på uppdrag av Havs- och vattenmyndigheten. Rapporten sammanfattar utveckling och beståndsstatus för de kommersiellt viktigaste fisk- och kräftdjursarterna i våra vatten. Bedömningar och förvaltningsråd är baserade på Internationella Havsforskningsrådets (ICES) rådgivning, SLU Aquas nationella och regionala provfiskedata, samt yrkesfiskets rapportering.
|
|
| 5. |
- Bryhn, Andreas, et al.
(författare)
-
Green lamps as visual stimuli affect the catch efficiency of floating cod (Gadus morhua) pots in the Baltic Sea
- 2014
-
Ingår i: Fisheries Research. - : Elsevier BV. - 0165-7836 .- 1872-6763. ; 157, s. 187-192
-
Tidskriftsartikel (refereegranskat)abstract
- This study compared catches in numbers (catch per unit effort, CPUE) and biomass (weight per unit effort, WPUE) of Atlantic cod (Gadus morhua) in two-chambered floating cod pots equipped with and without a green lamp as a form of visual stimuli in two areas. A green lamp inside the pot increased the CPUE and WPUE of cod above the maximum legal size (>38 cm) by 74 and 80%, respectively. There were no differences in CPUE and WPUE of small (<38 cm) cod caught in pots with and without a green lamp. By increasing the catch efficiency of cod green lamps could consequently be highly beneficial for the Baltic commercial cod pot fishery. (C) 2014 Elsevier B.V. All rights reserved.
|
|
| 6. |
- Bryhn, Andreas, et al.
(författare)
-
Predator damaged eel caught in coastal fisheries of the Baltic Sea
- 2023
-
Ingår i: Fisheries Research. - 0165-7836 .- 1872-6763. ; 267
-
Tidskriftsartikel (refereegranskat)abstract
- Fish stock assessment may be constrained by incomplete knowledge on all mortality sources. Seal and cormorant raiding fishing gear to access the catch has been asserted by fishers to be a considerable problem in the small-scale European eel fishery along the Swedish Baltic Sea coast. We analysed logbook data and found predator losses in fisheries at 13.6 ± 12.6% among catches landed in 16 Swedish harbours in subdivisions 25, 27 and 29 of the Baltic Sea in 2019–2021. These numbers were used to assess the total predator damage along this coast at 12 ± 10 tonnes of caught eel at a landings value (about 10% of the retail value) of 105,000 ± 97,000 euros in 2020. This may constrain prospects of the declining commercial small-scale coastal eel fishery. Moreover, this quantitative estimate may be useful in future assessments of the local stock component, with potentially important implications for ecological, economic and social sustainability.
|
|
| 7. |
- Calamnius, Linda, et al.
(författare)
-
Pontoon trap for salmon and trout equipped with a seal exclusion device catches larger salmons
- 2018
-
Ingår i: PLOS ONE. - : PLoS. - 1932-6203. ; 13:7
-
Tidskriftsartikel (refereegranskat)abstract
- The growing seal populations of the Baltic have led to more frequent interactions with coastal fisheries. The motivation for seals to interact with fishing gear is high. It provides high densities of fish. A successful means of mitigating the conflict is the pontoon trap. Seal visits here have been frequent. Seals have access to most parts of the trap system including the middle chamber, which is an overhead environment. Concerns have been raised about seals possible entanglement in this specific part of the trap. As a means of keeping seals from entering the middle chamber, two different Seal Exclusion Devices (SEDs) were tested. A diamond mesh SED and a square mesh SED, which was rotated 45. The aim was to compare the functionality of the different SEDs with respect to seal deterrent abilities and catch composition. The hypothesis tested were (i) that seals would not be able to enter the middle chamber, (ii) that the catch would increase and (iii) that the SED would deter larger fish from swimming into the middle chamber. Catch data and underwater film were collected. Larger salmons were caught in traps equipped with SEDs. The SEDs did not affect the number of caught fish or the total catch per soak day. © 2018 Calamnius et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
|
|
| 8. |
- Fetterplace, Lachlan, et al.
(författare)
-
AquaticVID: a low cost, extended battery life, plug-and-go video system for aquatic research
- 2023
-
Ingår i: Research Ideas and Outcomes. - 2367-7163. ; 9
-
Tidskriftsartikel (refereegranskat)abstract
- AquaticVID is a low-cost, long battery life video camera system for use in a wide-range of aquatic research applications. The system can be deployed for multiple day recording on a single charge, is submersible to depths of down to 950 m and can be constructed quickly using easily sourced off-the-shelf materials. The system is essentially ‘plug-and-go’, as assembly and preparation for deployment takes < 30 minutes without the need for technical build or programming skills. All of the electrical components are interchangeable with parts from multiple manufacturers and the camera system can be adapted to fit a variety of waterproof enclosure sizes depending on power and data storage requirements. Here, we describe three versions of the AquaticVID in detail and give examples of above and below water research undertaken with the system. The small size and extended battery times, coupled with ease of use and low cost (US$ 268–540) make the AquaticVID a useful option for numerous aquatic research applications.
|
|
| 9. |
- Hedgärde, Maria, et al.
(författare)
-
Avoiding grey seal depredation in the Baltic Sea while increasing catch rates of cod
- 2023
-
Ingår i: Fisheries Research. - : Elsevier BV. - 0165-7836 .- 1872-6763. ; 261
-
Tidskriftsartikel (refereegranskat)abstract
- The escalating conflict between gillnet fisheries and the growing seal populations in Baltic Sea has increased the need to reduce direct effects in form of reduced or damaged catches. This study describes the design and catch rates of 20 different seal safe cod (Gadus morhua) pot designs suitable for the Baltic Sea. Catches in numbers of individuals and total catch weight were recorded in 2762 pot hauls with pots varying in terms of size, shape, number of entrances, entrance length, pot placement in relation to the sea floor and catch holding chamber. The aim was to investigate the how the different designs and soak times affected the catch rates under similar conditions. Volume and soak time was significantly positively correlated with catch rates and round bottomstanding pots with a fish holding chamber, funnels and 5 entrances had the highest catch rates. The findings are important for the development of cod pots, which can allow the fishers to continue fishing in areas of high seal density with static gear and hence low-carbon emission and minimum bycatch of marine mammals and sea birds.
|
|
| 10. |
|
|
