The effects of selective harvest on Japanese Spanish mackerel (Scomberomorus niphonius) phenotypic evolution

Japanese Spanish mackerel (Scomberomorus niphonius) is an important fish species in the China Seas with wide distribution, extensive migration, and high economic value. This species has been yielding high fisheries production despite experiencing continuously high fishing pressure and the conversion from gillnet to trawl harvesting. Meanwhile, changes in life-history traits have been observed, including earlier maturation and smaller size at age. Here, we build an individual-based eco-genetic model parameterized for Japanese Spanish mackerel to investigate the population’s response to different fishing scenarios (fishing by trawl or by gillnet). The model allows evolution of life-history processes including maturation, reproduction and growth. It also incorporates environmental variability, phenotypic plasticity, and density-dependent feedbacks. Our results show that different gear types can result in different responses of life-history traits and altered population dynamics. The population harvested by gillnet shows weaker response to fishing than that by trawl. When fishing ceases, gillnet-harvested population can recover to the pre-harvest level more easily than that harvested by trawl. The different responses of population growth rate and evolution to different fishing gears demonstrated in this study shed light on the sustainable management and utilization of Japanese Spanish mackerel in the over-exploited China Seas.publishedVersio

SAM Fails to Segment Anything? -- SAM-Adapter: Adapting SAM in Underperformed Scenes: Camouflage, Shadow, and More

The emergence of large models, also known as foundation models, has brought significant advancements to AI research. One such model is Segment Anything (SAM), which is designed for image segmentation tasks. However, as with other foundation models, our experimental findings suggest that SAM may fail or perform poorly in certain segmentation tasks, such as shadow detection and camouflaged object detection (concealed object detection). This study first paves the way for applying the large pre-trained image segmentation model SAM to these downstream tasks, even in situations where SAM performs poorly. Rather than fine-tuning the SAM network, we propose \textbf{SAM-Adapter}, which incorporates domain-specific information or visual prompts into the segmentation network by using simple yet effective adapters. Our extensive experiments show that SAM-Adapter can significantly elevate the performance of SAM in challenging tasks and we can even outperform task-specific network models and achieve state-of-the-art performance in the task we tested: camouflaged object detection and shadow detection. We believe our work opens up opportunities for utilizing SAM in downstream tasks, with potential applications in various fields, including medical image processing, agriculture, remote sensing, and more

Influence of Aerosol Chemical Composition on Condensation Sink Efficiency and New Particle Formation in Beijing

Relatively high concentrations of preexisting particles, acting as a condensation sink (CS) of gaseous precursors, have been thought to suppress the occurrence of new particle formation (NPF) in urban environments, yet NPF still occurs frequently. Here, we aim to understand the factors promoting and inhibiting NPF events in urban Beijing by combining one-year-long measurements of particle number size distributions and PM2.5 chemical composition. Our results show that indeed the CS is an important factor controlling the occurrence of NPF events, with its chemical composition affecting the efficiency of the background particles in removing gaseous H2SO4 (effectiveness of the CS) driving NPF. During our observation period, the CS was found to be more effective for ammonium nitrate-rich (NH4NO3-rich) fine particles. On non-NPF event days, particles acting as CS contained a larger fraction of NH4NO3 compared to NPF event days under comparable CS levels. In particular, in the CS range from 0.02 to 0.03 s(-1), the nitrate fraction was 17% on NPF event days and 26% on non-NPF event days. Overall, our results highlight the importance of considering the chemical composition of preexisting particles when estimating the CS and their role in inhibiting NPF events, especially in urban environments.Peer reviewe

Latitudinal differences in early growth of largehead hairtail (Trichiurus japonicus) in relation to environmental variables

Largehead hairtail (Trichiurus japonicus) in the China Seas shows an increasing catch trend, despite continued overexploitation, which could be attributed to improved recruitment as a result of strengthened early growth. To understand the early growth variability of largehead hairtail, we examined the linkages between early growth, as revealed by otolith microstructure, and the associated environmental variables over both spatial and temporal scales. Young‐of‐the‐Year largehead hairtail were collected from three regions in the Bohai, Yellow and East China Seas between 29° and 39° N. Daily increment widths of sagittal otoliths were measured and used as a proxy for somatic growth. We found two spawning cohorts, Spring‐ and Summer‐spawned cohorts, that showed latitudinal differences in both mean growth and growth pattern. The transition time from larval to juvenile stage was identified at around 40 days. Daily increment widths of two cohorts showed similar growth pattern in the first 40 days, while location had a marked effect on daily growth over 41–110 days. This suggests physiologically constrained growth pattern in larval stage, but more plastic growth subject to habitat‐specific influences in juvenile stage. The gradient forest analysis identified sea bottom temperature, vertical temperature gradient, and sea surface salinity, as the most important variables in determining early growth. Latitudinal differences in early growth pattern and their response to environmental variables suggest adaptive plasticity of early growth, which has notable implication for the management and sustainable utilization of this important but heavily exploited resource in the China Seas.acceptedVersio

The effect of COVID-19 restrictions on atmospheric new particle formation in Beijing

During the COVID-19 lockdown, the dramatic reduction of anthropogenic emissions provided a unique opportunity to investigate the effects of reduced anthropogenic activity and primary emissions on atmospheric chemical processes and the consequent formation of secondary pollutants. Here, we utilize comprehensive observations to examine the response of atmospheric new particle formation (NPF) to the changes in the atmospheric chemical cocktail. We find that the main clustering process was unaffected by the drastically reduced traffic emissions, and the formation rate of 1.5 nm particles remained unaltered. However, particle survival probability was enhanced due to an increased particle growth rate (GR) during the lockdown period, explaining the enhanced NPF activity in earlier studies. For GR at 1.5-3 nm, sulfuric acid (SA) was the main contributor at high temperatures, whilst there were unaccounted contributing vapors at low temperatures. For GR at 3-7 and 7-15 nm, oxygenated organic molecules (OOMs) played a major role. Surprisingly, OOM composition and volatility were insensitive to the large change of atmospheric NOx concentration; instead the associated high particle growth rates and high OOM concentration during the lockdown period were mostly caused by the enhanced atmospheric oxidative capacity. Overall, our findings suggest a limited role of traffic emissions in NPF.Peer reviewe

The effects of selective harvest on Japanese Spanish mackerel (Scomberomorus niphonius) phenotypic evolution

Japanese Spanish mackerel (Scomberomorus niphonius) is an important fish species in the China Seas with wide distribution, extensive migration, and high economic value. This species has been yielding high fisheries production despite experiencing continuously high fishing pressure and the conversion from gillnet to trawl harvesting. Meanwhile, changes in life-history traits have been observed, including earlier maturation and smaller size at age. Here, we build an individual-based eco-genetic model parameterized for Japanese Spanish mackerel to investigate the population’s response to different fishing scenarios (fishing by trawl or by gillnet). The model allows evolution of life-history processes including maturation, reproduction and growth. It also incorporates environmental variability, phenotypic plasticity, and density-dependent feedbacks. Our results show that different gear types can result in different responses of life-history traits and altered population dynamics. The population harvested by gillnet shows weaker response to fishing than that by trawl. When fishing ceases, gillnet-harvested population can recover to the pre-harvest level more easily than that harvested by trawl. The different responses of population growth rate and evolution to different fishing gears demonstrated in this study shed light on the sustainable management and utilization of Japanese Spanish mackerel in the over-exploited China Seas

The effects of selective harvest on Japanese Spanish mackerel (Scomberomorus niphonius) phenotypic evolution

Japanese Spanish mackerel (Scomberomorus niphonius) is an important fish species in the China Seas with wide distribution, extensive migration, and high economic value. This species has been yielding high fisheries production despite experiencing continuously high fishing pressure and the conversion from gillnet to trawl harvesting. Meanwhile, changes in life-history traits have been observed, including earlier maturation and smaller size at age. Here, we build an individual-based eco-genetic model parameterized for Japanese Spanish mackerel to investigate the population’s response to different fishing scenarios (fishing by trawl or by gillnet). The model allows evolution of life-history processes including maturation, reproduction and growth. It also incorporates environmental variability, phenotypic plasticity, and density-dependent feedbacks. Our results show that different gear types can result in different responses of life-history traits and altered population dynamics. The population harvested by gillnet shows weaker response to fishing than that by trawl. When fishing ceases, gillnet-harvested population can recover to the pre-harvest level more easily than that harvested by trawl. The different responses of population growth rate and evolution to different fishing gears demonstrated in this study shed light on the sustainable management and utilization of Japanese Spanish mackerel in the over-exploited China Seas

Exploring fishing impacts on the structure and functioning of the Yellow Sea ecosystem using an individual-based modeling approach

The Yellow Sea is a marginal sea in the Northwestern Pacific where the fishery resources have been overfished and the community structure has greatly changed over the past six decades. Ecosystem modeling approaches are valuable tools to uncover potential mechanisms behind the ecosystem changes. Here, we developed ‘OSMOSE-YS’, an individual-based multi-species OSMOSE model that includes important commercial pelagic and demersal fish and invertebrates in the Yellow Sea. Simulations were carried out under three fishing scenarios to investigate how different levels of fishing pressure may have impacted the Yellow Sea ecosystem. Results indicate that the biomass of demersal fish continued to decline during 1970–2014, while the biomass of pelagic fish and invertebrates fluctuated periodically. Long-term fishing pressure has led to the reduction of total biomass, body sizes, and longevity of the modelled species. Under low-fishing condition, the ecosystem biomass is restored and the proportion of elder and larger individuals increases. On the contrary, high-fishing condition further decreases the proportion of high-trophic-level species. OSMOSE-YS serves as a baseline model to investigate ecosystem responses to different fishing strategies, in support of ecosystem-based fisheries management in the Yellow Sea.acceptedVersio

The bio-economic effects of artificial reefs: mixed evidence from Shandong, China

Artificial reefs are used to protect coastal habitats and rebuild fisheries. This engineering approach to fisheries management has gained popularity in many coastal areas, including China. In Shandong province alone, over USD 50 million were invested in artificial reefs during 2005–2013. Have artificial reefs achieved their biological and economic objectives? We compared reef and control sites in terms of catch and value per unit effort and average body length across species, based on surveys carried out during 2012–2013. We found that in aggregate, with all fish and invertebrates combined, artificial reefs did not improve the overall catches or revenues. Instead, seasonal fluctuations were prominent. However, when we allow for species-specific differences and focus on the common fish species, we find that an artificial reef can increase the catch and value per unit effort on average by approximately 40% compared to the control sites. The difference between these contrasting results occurs because some of the dominant species that comprise the bulk of the catches did not benefit from the reef, while many of the less dominant ones did so. This underlines the importance of being specific about what is meant by “benefiting fisheries” when evaluating artificial reefs, as well as when the objectives of reef projects are formulated in the first place. The positive effects of artificial reefs can be caused by the reefs themselves and by their influence on fishing patterns. Our study was not designed to separate these effects but we suggest that in Shandong, restrictions on fishing access may have been as important as the presence of the reef itself