| 1. |
|
|
| 2. |
- Bauer, Barbara, et al.
(författare)
-
Model uncertainty and simulated multispecies fisheries management advice in the Baltic Sea
- 2019
-
Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 14:1
-
Tidskriftsartikel (refereegranskat)abstract
- Different ecosystem models often provide contrasting predictions (model uncertainty), which is perceived to be a major challenge impeding their use to support ecosystem-based fisheries management (EBFM). The focus of this manuscript is to examine the extent of model disagreements which could impact management advice for EBFM in the central Baltic Sea. We compare how much three models (EwE, Gadget and a multispecies stock production model) differ in 1) their estimates of fishing mortality rates (Fs) satisfying alternative hypothetical management scenario objectives and 2) the outcomes of those scenarios in terms of performance indicators (spawning stock biomasses, catches, profits). Uncertainty in future environmental conditions affecting fish was taken into account by considering two seal population growth scenarios and two nutrient load scenarios. Differences in the development of the stocks, yields and profits exist among the models but the general patterns are also sufficiently similar to appear promising in the context of strategic fishery advice. Thus, we suggest that disagreements among the ecosystem models will not impede their use for providing strategic advice on how to reach management objectives that go beyond the traditional maximum yield targets and for informing on the potential consequences of pursuing such objectives. This is especially true for scenarios aiming at exploiting forage fish sprat and herring, for which the agreement was the largest among our models. However, the quantitative response to altering fishing pressure differed among models. This was due to the diverse environmental covariates and the different number of trophic relationships and their functional forms considered in the models. This suggests that ecosystem models can be used to provide quantitative advice only after more targeted research is conducted to gain a deeper understanding into the relationship between trophic links and fish population dynamics in the Baltic Sea.
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
|
|
| 7. |
- Belgrano, Andrea, et al.
(författare)
-
Workshop on Ecosystem Based Fisheries Advice for the Baltic (WKEBFAB; outputs from 2021 meeting)
- 2022
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The main aim of the meeting was to organise a meeting with members of the ICES/HELCOM Working Group on Integrated Assessments of the Baltic Sea (WGIAB) and the ICES Baltic Fisheries Assessment working group (WGBFAS), as well as invited experts on ecosystem-based fisheries management from other sea regions, to propose a roadmap towards providing ecosystem based fisheries advice (EBFAdvice) for the Baltic Sea. The specific objective was to conclude on ecosystem aspects that could be added to the fisheries advice provided by ICES. In order to achieve this, the WK reviewed working international EBF approaches, reviewed ecosystem indicators relevant for EBFAdvice in the Baltic and evaluated how existing ecosystem models can be used for giving advice on ecosystem-based catch options. The lack of management strategy evaluations implemented for the Baltic Sea became apparent and the WK stresses their development and application as a key step for implementation of EBFAdvice. Several ecosystem indicators are currently operational for the Baltic Sea region, mainly via developments in HELCOM and in relation to the Marine Strategy Framework Directive. These indicators could potentially support an EBFAdvice by providing an integrated ecosystem assessment framing, but further work is needed to assess how selected existing indicators could be analytically linked to the developing EBFAdvice. The WK proposed a roadmap on utilising ecosystem information in stock assessment and advice for the Baltic Sea over 2022-2023. As a central aim for the work, the WK agreed to test the use of Scaling factors for the species-specific long term Ftarget derived catch options (hence, applying an approach similar to the Feco approach developed by WKDICE and WKIRISH). The WK also proposed to produce Ecological and socio-economic profiles (ESP) of the specific stocks, which would identify quantitative indicators/factors for ecological processes that can be used to scale the species-specific Ftarget. Additionally, the WK proposed to amend the regular fisheries advice with information on Ecosystem consequences / Ecosystem risks as a result of the stock specific advice in question. The WK agreed that at its first stage of implementation, the EBFAdvice would focus on developing the F scaling factor, ESP and risks, as described above, in relation to the already existing single species assessment and stock-prediction models (while in the long term, multi-species or specific food web models would preferentially be used). It was identified that the implementations should be part of the ICES Benchmark process, where the approach would be tested and accepted. The proposed next benchmark of the small pelagic stocks in the Baltic 2022-2023, creates the first window of opportunity to test scaling factors. The WK recommends that the F scaling factor, ESP and risks be formulated in such a way that they can be integrated into existing ICES advice products, namely the advice on fishing opportunities, the Baltic Sea Ecosystem Overview and the Baltic Sea Fisheries Overview. The WK, further, proposed a number of changes to the ICES advisory process, in order to facilitate the operationalization of the roadmap and EBFAdvice. The work required to eventualize the proposed roadmap is dependent on further funding, and is foreseen to be facilitated by two more workshops (WKEBFAB 2 and 3). It should be noted that the working group for integrated assessment (WGIAB) has already suggested in their meeting ToRs for 2022-2024 to assist in the work of WKEBFAB and this collaboration is expressed as an item in the TORs.
|
|
| 8. |
|
|
| 9. |
|
|
| 10. |
- Howell, Daniel, et al.
(författare)
-
Interim Report of the Working Group on Multispecies Assessment Methods (WGSAM)
- 2018
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The pan-regional Working Group on Multispecies Assessment Methods (WGSAM) met in San Sebastian, Spain, 16–20 October 2017. In this eleventh report of the group, work focused on three of the multi-annual ToRs (B, C, D). Based on their knowledge, participants provided an updated inventory of progress of multispecies models in ICES Ecoregions (ToR A), noting those regions where no information was available. A Key Run (ToR B) of the North Sea Stochastic Multispecies Model (SMS) was presented and reviewed in detail by 4 WGSAM experts, and approved by the group following implementation of changes agreed in plenary at the meeting and verified by a subset of experts post-meeting. The Key Run is documented in detail in Annex for ToR B, with key outputs summarised in Section 5 and data files made available on the WGSAM webpage and the ICES expert group Github (https://github.com/iceseg/wg_WGSAM). Since the M2 values are used for the assessment of important North Sea stocks, it is recommended to publish the annex also on the official stock annex website. In addition, WGSAM does not recommend updating existing data series of natural mortality by simply adding the latest three new years. The timeseries as a whole shows patterns which are not retained by this procedure. Multispecies model skill assessment (ToR C) and multi-model ensemble methods (ToR D) were emphasized this year. Considerable progress has been made towards advancing both aspects of multispecies modelling. Investigation of skill assessment and ensemble methods and case studies is critical to ensure that outputs of multispecies assessment models are reliable for use in operational assessment and to inform management decisions. Progress was also made on investigations of top predator impacts on managed fish across several regions (ToR F), including the North Sea where new information was included in the SMS key run. Further progress was also made on multispecies and ecosystem level reference points and harvest control rules in mixed fisheries (ToR G).
|
|
