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Mamyshev oscillators have pushed the frontiers in output parameters of ytterbium- and erbium-based ultrafast fiber oscillators in the spectral region around 1 µm and 1.5 µm within the last few years tremendously. In order to expand the superior performance toward the 2 µm spectral region, we present in this Letter an experimental investigation of the generation of high-energy pulses by a thulium-doped fiber Mamyshev oscillator. Generating highly energetic pulses is enabled by a tailored redshifted gain spectrum in a highly doped double-clad fiber. The oscillator emits pulses with an energy of up to 15 nJ, which can be compressed to 140 fs.

Harmful fisheries subsidies contribute to overfishing leading to environmental and societal impacts1. If only fisheries within the subsidising nations’ jurisdiction were affected, then unilateral actions might be sufficient to help safeguard our ocean and the people reliant upon it. However, just as fish move between jurisdictions2, so too do the subsidised fishing fleets targeting them3. As such, the impacts and solutions to subsidies-induced overfishing are matters of international concern. Mapping that impact is therefore key to understanding these concerns and informing multilateral reform. Here we combine existing datasets4–6 to quantify the amount of harmful fisheries subsidies impacting the high seas, domestic and foreign waters, respectively. We estimate that between 24% and 43% of all harmful fisheries subsidies impact foreign waters or the high seas. We show that harmful subsidies primarily originate from countries with high-Human Development Index (HDI), strong fisheries management capacity and relatively sustainable fish stocks, yet disproportionately impact countries with low-HDI, lower management capacity and more vulnerable stocks. Indeed, over 40% of the harmful subsidies impacting low-HDI countries originate from high-HDI countries. This discrepancy between the source of harmful subsidies and the nations that are ultimately impacted is unsustainable and unjust. Policy-makers from all nations must push for effective multilateral subsidies reform. Prohibiting subsidies to distant-water fishing should be prioritised to support equitable and sustainable fisheries worldwide.

Ultrafast Thulium-doped fiber oscillators and amplifiers have become increasingly relevant over the past few years for applications like precise processing of polymers, as well as driving nonlinear frequency conversion stages to cover the fingerprint region in the mid-infrared and the soft X-ray spectral region [1] – [3] . Those applications require high peak powers or respective high pulse energies, which are usually generated by master oscillator power amplifier setups with several subsequent amplification stages. Reducing the number of amplification stagse would enable a more compact setup. Due to a higher tolerance for nonlinear phase accumulation compared to established pulse evolution schemes, Mamyshev oscillators (MO) are promising to omit one amplification stage in the future.

The magnitude of subsidies provided to the fishing sector by governments worldwide is immense—an estimated $35.4 billion USD per year. The majority of these subsidies may be impeding efforts to sustainably manage fisheries by incentivizing overfishing and overcapacity. Recognizing the threat these subsidies pose, the World Trade Organization has set a goal of reaching an agreement that would end fisheries subsidies that contribute to overcapacity, overfishing, and illegal fishing. However, negotiations have been hampered by uncertainty around the likely effects of reforming these subsidies. Here we present a novel method for translating a bioeconomic model into an interactive online decision support tool that draws upon real-world data on fisheries subsidies and industrial fishing activity so users can directly compare the relative ambition levels of different subsidy reform options.

The principle of a Mamyshev oscillator depends on alternating spectral filtering between sections of spectral broadening by self-phase modulation. In the 2 µm wavelength range, this concept faces the difficulty that standard fibers are anomalous dispersive which limits the possible pulse energy to the pJ-regime without proper dispersion management. We applied ultra-high numerical aperture fibers with normal dispersion in order to achieve up-chirped pulses in an anomalous dispersive Thulium-doped gain fiber. With that design, we achieved mode-locked pulses with energies of 6.4 nJ and a compressed autocorrelation duration of 195 fs at a repetition rate of 16 MHz.

We present experimental results of the generation of ultrashort pulses in the 2 µm wavelength region by a fiber Mamyshev oscillator, along with the simulation of the pulse propagation in the cavity. The Mamyshev oscillator emitted pulses with energies of 3.55 nJ at a repetition rate of 15 MHz and optical spectra with bandwidths of 48 nm. The pulses propagated in anomalous dispersive Thulium-doped fiber sections with dispersion compensation sections of normal dispersive fibers.

November 2021 could see members of the World Trade Organization (WTO) reach an agreement to prohibit harmful fisheries subsidies, culminating over 20 years of negotiation and discussion. This commentary highlights strengths and places where the current draft text can be improved to ensure the agreement truly contributes to sustainable and equitable fisheries. Overall, conditionalities and exemptions are better streamlined and defined, time periods to enter into compliance are allowed yet reasonably short, types of subsidies to be particularly avoided are clearly noted, and appropriate emphasis is placed on reducing impacts from distant-water and transboundary fishing fleets. Key places for improvement relate to unspecific language on supporting fisher incomes, the uniform handling of illegal, unreported, and unregulated fisheries (IUU), and transparency in distant water fisheries, issues partly stemming from historical definitions that are useful for some fisheries but may not capture the complexity of others. Capacity-enhancing subsidies should be avoided, and it is important to avoid further negative impacts on marginalized fisher populations. Given the importance of reaching an agreement without further delay, we urge members to proactively and inclusively formalize their fishing definitions and practices to prevent inequitable outcomes for vulnerable fishers during the implementation stage of a new agreement. A WTO agreement to prohibit harmful fisheries subsidies is an opportunity to catalyze the design and funding of improved and cooperative national and international fisheries policy and management strategies, to the benefit of fishers, global seafood production, and indeed all who hold relationships with our oceans.

This article presents the first bottom-up analysis of the proportion of global marine fisheries subsidies to small-scale fisheries (SSF). Using existing data, the reported national subsidy amounts are split into the fraction that goes to small- and large-scale fishing sectors. Results reveal a major imbalance in subsidy distribution, with SSF receiving only about 16% of the total global fisheries subsidy amount of $35 billion in 2009. To bring this into perspective, a person engaged in large-scale fishing received around 4 times the amount of subsidies received by their SSF counterparts. Furthermore, almost 90% of capacity-enhancing subsidies, which are known to exacerbate overfishing go to large-scale fisheries, thus increasing the unfair competitive advantage that large-scale fisheries already have. The developmental, economic and social consequences of this inequity are huge and impair the economic viability of the already vulnerable small-scale fishing sector. Conclusions indicate that taxpayers' money should be used to support sustainable fishing practices and in turn ocean conservation, and not to foster the degradation of marine ecosystems, often a result of capacity-enhancing subsidies. Reducing capacity-enhancing subsidies will have minimal negative effects on SSF communities since they receive very little of these subsidies to begin with. Instead, it will help correct the existing inequality, enhance SSF economic viability, and promote global fisheries sustainability.

Small-scale fisheries depend on availability of and access to resources. Yet research on access – the combination of rights and capacities that enable fishers to benefit from available resources – has been limited compared to research on availability in Canadian fisheries. We surveyed 118 independent fishers in British Columbia, Canada to understand access rights (harvesting, entrance, transferability, security and protection), capacities (physical, human, social, cultural, political and financial assets), economic benefits from fishing, and actions to maintain or increase access. Participants generally perceived: strengths in physical, human and cultural assets; varied status in social and financial assets; and weaknesses in political assets. Access rights were generally perceived as poor with the exception of transfer rights. We employed modeling approaches to understand demographic characteristics of participants with higher rights and capacity, and which factors predicted feasibility and economic benefits of fishing. Higher perceived rights and capacities were both predicted by whether the participant self-identified as Indigenous. Higher feasibility of fishing was associated with higher political and financial assets, higher rights, being non-Indigenous, rural residence, and higher incomes. Higher income from fishing was predicted by higher financial assets and being non-Indigenous. Qualitative results showed participants maintain or gain access through: preparation; non-political networking; political advocacy; augmenting licenses or quota; or, diversification and intensification of fishing activities. Yet, many participants reported feeling powerless. Our research emphasizes the need to address access in fisheries management. Our novel conceptualization and mixed methods approach to study access rights and capacities can be adapted and applied elsewhere.

The period from 2019 to 2020 is critical in determining whether the World Trade Organization (WTO), tasked with eliminating capacity-enhancing fisheries subsidies, can deliver to the world an agreement that will discipline subsidies that lead to overfishing. Here, following extensive data collection efforts, we present an update of the current scope, amount and analysis of the level of subsidisation of the fisheries sector worldwide. We estimate global fisheries subsidies at USD 35.4 billion in 2018, of which capacity-enhancing subsidies are USD 22.2 billion. The top five subsidising political entities (China, European Union, USA, Republic of Korea and Japan) contribute 58% (USD 20.5 billion) of the total estimated subsidy. The updated global figure has decreased since the most recent previous estimate from 2009, of USD 41.4 billion in 2018 constant dollars. The difference between these two estimates can be largely explained by improvements in methodology and the difference in the actual amount of subsidies provided. Thus, we consider direct statistical comparison of these numbers to be inappropriate. Having said that, the difference between the estimates suggest that the increase in fisheries subsidies provided in the preceding decades may have halted. Still, the bulk of harmful ‘capacity-enhancing’ subsidies, particularly those for fossil fuels have actually increased as a proportion of total subsidies. As such, for the benefit of marine ecosystems, and current and future generations of people, all hands must be on deck in helping the WTO reach a meaningful agreement to discipline subsidies that lead to overcapacity and overfishing.