In the past two decades, little information has been updated to understand the resource status of the crab species Ovalipes punctatus in the East China Sea Region. In this study, we conducted surveys in 2018 and 2019 to identify the seasonal spatial distribution patterns of the economically important sand crab Ovalipes punctatus (De Haan 1833) in the southern Yellow and East China Seas. In the study area, the largest biomass of crabs was observed in the fishing grounds of Dasha and the Yangtze River mouth, and the second largest biomass was detected in the Jiangwai-Zhouwai area. Seasonally, the total biomass order in these areas was summer > autumn & winter > spring, and the mean average individual weight order was spring & summer > winter > autumn. These findings provided maps of the seasonal spatial distribution pattern of the species across seasons, which were then used in climate-change scenario models. Model predictions suggested that O. punctatus might migrate northward and offshore under climate warming conditions, and that the climate scenario SSP585-2100 might be the most negative case, respectively, for the habitat area of gain% minus loss%. These data can be used to develop robust and systematic regional fisheries resource management policies that consider adaptation measures to address the impact of environmental and climate change along China’s coasts and other areas in the world.

In real fisheries management practices, ecological information on the seasonal distribution patterns and characteristics of marine economic fauna and responses to climate change is necessary. In this study, we analyzed data obtained from surveys conducted between 2018 and 2019 in the southern Yellow and East China Seas, using ensemble models to predict variations in the habitat area of Metapenaeopsis provocatoria longirostris across seasons and under different climate scenarios. The highest abundances were observed at the following water temperature and salinity conditions, respectively: 18.5 °C and 34.5‰–35‰ in spring, 18.9–28 °C and 33.4–34.6‰ in summer, 18.6–21.7 °C and 33.5–34.4‰ in autumn, and 18–21.5 °C and 34‰ in winter. The major cohort was concentrated at depths of 100–110 m and 85–105 m in spring and summer, respectively, and at 80–100 m and 70–120 m in autumn and winter, respectively. In spring and winter, M. provocatoria longirostris was distributed in the continental shelf waters of the East China Sea, at wider salinity (30–35‰) and water temperature (8–26 °C) ranges, whereas in summer and autumn, the distribution shifted offshore. The values predicted for habitat loss under different climate scenarios were ranked as follows: ~70% loss under SSP585-2100 > ~50% loss under SSP370-2100 > ~30% loss under SSP245-2100 > ~15% loss under SSP126-2100 and SSP370-2050 > ~1–5% under SSP126-2050, SSP245-2050, and SSP585-2050. No great gains in habitat were predicted under any scenario. Our findings can contribute to the establishment of appropriate fisheries management schemes for the rational exploitation of M. provocatoria longirostris. Our predictions can assist in improving fisheries management practices within the context of climate change.

Shrimp populations are threatened by overfishing and climate change. Despite this, there are limited studies on the variations in biomass, number, and size of Eastern Neptune rose shrimp, Parapenaeus fissuroides, in different fishing grounds across seasons in the Southern Yellow and East China Seas of China, as well as habitat area change under different climate scenarios. In this study, the data was obtained from the bottom trawling surveys conducted from November 2018 to September 2019 at 26.5–35° N 120–127° E. We found that the major cohorts were concentrated at depths of 70–110 m in spring and summer, 80–90 m in autumn, and 60–100 m in winter. The greatest abundance was observed at sea bottom temperatures of 18–20 °C in spring, 18–21 °C in summer, 19–22 °C in autumn, and 17–19 °C in winter; and sea bottom salinity levels of 34–35 across all four seasons, indicating the influence of high-salinity Taiwan Warm Current and Yellow Sea Warm Current. The annual mean catch per unit effort in weight and number were 16,623.65 g·h⁻¹ and 4304.525 ind·h⁻¹, respectively. Climate variations may negatively impact the habitat area range of P. fissuroides. For migration route, P. fissuroides concentrates in Yushan and Yuwai for the upcoming spawning season in spring, with offspring occurring in high-temperature and high-salinity waters of Zhouwai and Yuwai in summer. The newborn recruited cohorts remained in Yushan, Wentai, and Mindong for nursery grounds in autumn and winter. We suggested a seasonal closure from August to November in Yushan, Yuwai, Zhouwai, and Mindong to protect and conserve P. fissuroides populations.

It is important to understand the ecological information of Metapenaeopsis dalei to better conserve and manage the stocks in Asia. In this study, we employed research vessels to collect the field data including biomass and number of M. dalei in each survey stations along with environmental data including depth, water temperature, and salinity from November 2018 to September 2019 in the region of 26.50–35.00° N and 120.00–127.00° E in the southern Yellow and East China Seas of China. We found that the annual mean catch per unit effort of weight and number (CPUE_w and CPUE_n) was 15,235.89 g∙h⁻¹ and 17,319.13 ind∙h⁻¹, respectively. Metapenaeopsis dalei was found in 10–130 m. The greatest biomass occurred at 10–20 m in spring, 30–40 m in summer, 10–100 m in autumn, and 10–40 m in winter. The greatest abundance occurred at sea bottom temperature (SBT) 14–15 °C in spring, 19 °C in summer, 15–20 °C in autumn, and 10–12 °C in winter. The greatest abundance occurred at sea bottom salinity (SBS) 32–33 in spring, 32 in summer, 32–35 in autumn, and 31–32 in winter. We found the lowest SBT of M. dalei at 10–11 °C in spring and summer. The juveniles were found at SBT 21 °C and SBS 34 in autumn. The total CPUE_w and CPUE_n rankings were winter > spring > autumn > summer, and the mean average individual weight (AIW) ranking was summer > spring > winter > autumn. Fishing grounds of Haizhou Bay–Lvsi and Zhoushan–Yushan may be the spawning grounds for M. dalei. These findings can benefit fishery management action and planning in the future.

Charybdis (Gonioneptunus) bimaculata (Miers, 1886), C. (Charybdis) japonica (A. Milne-Edwards, 1861), and C. (Charybdis) miles (De Haan, 1835) are dominant target species harvested by small-scale artisanal fisheries in the coastal waters of China. Characterizing their spatial distribution and interannual population variability is critical for sustainable crustacean stock conservation. Previous investigations of these three Charybdis congeners have been limited to short-duration, single-season, or geographically restricted descriptive surveys, with no systematic cross-species comparison of seasonal habitat use. This has created major knowledge gaps regarding their long-term spatiotemporal dynamics and ecological niche partitioning. We conducted standardized bottom-trawl surveys aboard research vessels across the southern Yellow Sea and East China Sea from 2018 to 2021 to quantify numerical abundance and biomass of the three congeneric crabs. Two species distribution modeling frameworks—Generalized Additive Models (GAMs) and Boosted Regression Trees (BRTs)—were implemented to generate fine-resolution seasonal habitat suitability maps for each species. We identified minimum thermal thresholds for species presence: bottom water temperature > 8 °C for C. bimaculata and >10 °C for C. miles. Core aggregation zones of C. bimaculata and C. japonica occurred in waters adjacent to the Yangtze River Estuary (32–34° N), whereas C. miles predominated in offshore habitats of the southern East China Sea (27–31° N). In this study, C. bimaculata favors shallow seas with warm bottom water and euryhaline conditions, C. japonica prefers low-salinity coastal waters with cold bottom water, and C. miles thrives in deep, high-salinity offshore waters with eurythermal tolerance. The findings of this study can contribute to the sustainable fisheries management and conservation of these species.

The swimming crabs Monomia argentata (A Milne-Edwards, 1861) and Portunus sanguinolentus (Herbst, 1783) are warmwater commercial crab species that inhabit sandy–muddy substrates in Chinese Seas. Little information is available regarding for either species regarding the northernmost distribution limit and distribution pattern (including migration route) related to environmental factors in the East China Sea. In this study, bottom trawl surveys were conducted to collect biomass data across the seasons in 2018 to 2019. The total catch per unit effort in weight (CPUEw) values recorded for M. argentata were 183.5, 98.7, 1,752.1, and 928.8 g·h–1 in spring, summer, autumn, and winter, respectively, whereas the total CPUEw values recorded for P. sanguinolentus were 9,218.1, 1,901, and 135.7 g·h–1 in summer, autumn, and winter. In November, the favorable sea bottom temperature (SBT), sea bottom salinity, and depth values recorded for M. argentata were 19°C–21°C, 34–35, and approximately 80 m, respectively, whereas the corresponding values for P. sanguinolentus were 21°C–22°C, 34–35, and 70–80 m; however, in January, the favorable corresponding values for M. argentata and P. sanguinolentus were 16°C–20°C, 34–35, and 80–100 m, respectively, and 25°C–28°C, 32–33, and 40–50 m, respectively. It is suggested that juvenile M. argentata concentrated in the offshore water area of the Yushan fishing ground in autumn, migrated from Yushan (when SBT was below 18°C) to the overwintering grounds, such as Zhouwai, Yuwai, and Wentai, in winter, and returned to (when SBT exceeded 18°C) and remained in Yushan and Wentai in spring and summer, respectively. In contrast, the juveniles of P. sanguinolentus concentrated in the inshore water area of the Wentai fishing ground in summer and autumn. The findings presented herein provide baseline data for researchers and policymakers to conserve and manage the two crab resources in the future.