Ecological balance and stable economic development are crucial for the fishery. This study proposes a predator-prey system for marine communities, where the growth of predators follows the Allee effect and takes into account the rapid fluctuations in resource prices caused by supply and demand. The system predicts the existence of catastrophic equilibrium, which may lead to the extinction of prey, consequently leading to the extinction of predators, but fishing efforts remain high. Marine protected areas are established near fishing areas to avoid such situations. Fish migrate rapidly between these two areas and are only harvested in the nonprotected areas. A three-dimensional simplified model is derived by applying variable aggregation to describe the variation of global variables on a slow time scale. To seek conditions to avoid species extinction and maintain sustainable fishing activities, the existence of positive equilibrium points and their local stability are explored based on the simplified model. Moreover, the long-term impact of establishing marine protected areas and levying taxes based on unit catch on fishery dynamics is studied, and the optimal tax policy is obtained by applying Pontryagin\'s maximum principle. The theoretical analysis and numerical examples of this study demonstrate the comprehensive effectiveness of increasing the proportion of marine protected areas and controlling taxes on the sustainable development of fishery.

Freshwater and marine ecosystems are a suitable habitat for parasitic nematodes of the genus Contracaecum (family: Anisakidae) to complete their complex life cycle. Several fish species of the Sea of Galilee (Lake Kinneret) were reported in 1964 as second intermediate/paratenic hosts of Contracaecum spp. larvae. The lack of taxonomically relevant morphological features of these larvae hindered their proper identification. Here we report the results of a 1-year survey conducted in 2021, 57 years after the first (and only) such survey. We analyzed 352 specimens from 10 fish species (native and non-native) of the Sea of Galilee (Israel) ichthyofauna. We compared our results with those of the first parasitological survey conducted by Paperna in 1964; the overall prevalence of nematodes referable to Contracaecum larvae was 16.8% and 0.85% in 1964 and in 2021, respectively. Different from the first survey that identified Contracaecum larvae morphologically, we used both morphological and molecular tools. Two wild native cyprinids-Jordan himri (Carasobarbus canis) and Jordan barbel (Luciobarbus longiceps)-were infected (a single specimen each) with Contracaecum quadripapillatum larvae in their abdominal cavity. A single specimen of blue tilapia (Oreochromis aureus) was infected with two larvae of Contracaecum multipapillatum E, localized in the pericardial cavity. The findings of our study, which is part of a large project focused on Contracaecum spp. infecting both piscivorous birds and fish collected in Israel, advance our knowledge about the distribution and host range of this potentially zoonotic parasite in fishery products of the Sea of Galilee.

Climate change is one of the most concerning topics in the Anthropocene. Increasing sea water temperature will trigger a series of ecological consequences, altering the various functions and services that marine ecosystems provide for humans. Fisheries, specifically, will likely face the most direct impact. China provides unparalleled catches with enormous and intensive fishing effort, and China Seas are suffering from significantly increasing water temperature. However, uncertainties in the impacts of climate change on fishing species and fisheries in the China Seas present challenges for the formulation of coping and adapting strategies. Here, we employed a climate risk assessment framework to evaluate the climate risks of fishing species and fisheries of various provinces in China in the past decade, aiming to benefit the development and prioritization of appropriate adaptation options to climate change. Results show that considering the water temperature in the 2010s, 20 % of fishing species in the China Seas have one-fourth of their habitats unsuitable, and the situation will become worse with future warming scenarios in the 2050s when nearly half of species will have at least one-fourth of their habitats no longer suitable. Integrating hazard, exposure and vulnerability, climate risks to fisheries feature heterogeneity among provinces. Climate risks to fisheries of northern provinces are characterized by low hazard and high exposure, while the southern counterparts are largely determined by high hazard and low exposure. Climate change is threatening fishing species and remarkably altering fishery patterns in China Seas. Shifting fishing targets, increasing fishing efficiency, raising catch diversity, and updating fishery-related industries would be effective steps to help fisheries adapt to climate change, and adaptation strategies need to be tailored considering local realities.

Developmental policies in low- and middle-income countries pose immense potential within the agriculture sectors to escalate economic growth and development. Almost one-half of the workforces continue to be engaged in agriculture and allied activities with a relatively lower economic contribution than those employed in other sectors. Hence, realizing such potential however requires tremendous scaling up of skill development activities in the sector. Investing in skill development of workers engaged in agricultural and allied activities can potentially display notable value additions, income generation and therefore reductions in widespread deprivations in the form of food insecurity and undernutrition. Further with the direct link between nutrition and productivity, economic gains, it is further imperative to impart market exposure among subsistence and unskilled workers. This study therefore empirically investigates the association between households\' primary occupation and caloric deprivation in India. In particular, in a multivariate and multilevel framework, we identified how closely primary occupation of households explain the variation in caloric deprivation in India.
Drawing upon data from 68th round (2011-12) of nationally representative cross-sectional Household Consumer Expenditure Survey (HCES) of National Sample Survey (NSS), Government of India, we examined the association between occupational backgrounds of households and caloric deprivation (average caloric consumption as well as low calorie intake) among Indian households.
Evidences show that agricultural and fishery labor households have lowest calorie intake (2086 kcal) across all the occupational groups. However, market oriented skilled agricultural and fishery workers\' (2261 kcal - rural, 2165 kcal - urban) have higher calorie intakes than those belonging to subsistence agricultural (2165 kcal - rural, 2149 kcal - urban). Further, the multilevel logistic regression estimates suggest that in rural areas, households engaged in skilled agricultural and fishery works have significantly (at 5% level) lower odds ratio (OR: 0.72, with 95% CI: 0.63; 0.82) of having insufficient calorie intake compared to the unskilled agricultural and fishery laborer households. Estimates from variance partitioning based on multilevel logistic regression models suggest that the households\' occupational group accounts for 7 to 14% of total variation in calorie consumption.
These insights when combined with the occupation-specific random-effects suggest that investing in skill development of agricultural and fishery workers may have immense potential to strengthen their nutritional status and to reduce deprivation levels.

Enclosure fisheries have accommodated the widespread expansion of aquaculture in many lakes throughout the Yangtze Plain (YP), China, for over four decades. Such practices have increased food provision but have also triggered various detrimental environmental consequences. To restore ecosystem functions, the Chinese government recently implemented specific regulations to remove enclosure fences from lakes throughout the YP. However, little information is available on the spatial and temporal distributions of the enclosure fences, particularly in relation to the enforcement of recent policy changes. Using synthetic aperture radar (SAR) satellite images taken between 2002 and 2018, we conducted the first comprehensive assessment of the interannual changes in enclosure fences in 17 large lakes throughout the YP. Consistent decreases in fence density were found in most lakes after 2015; 15 lakes had >50% of their fences removed, while 9 lakes had >90% removed. The timing and implementation of the development and destruction of enclosure fisheries were related to government policy; before 2015, regional dynamics in enclosure fisheries were attributed to provincial policies, whereas the nearly ubiquitous fence demolition after 2015 was likely a response to national policy. This study represents remotely sensed evidence that demonstrates the importance of both local and national environmental policies and their effectiveness in mitigating ongoing human impacts on vulnerable and valuable natural resources. These findings provide valuable baseline information for future lake environmental monitoring and restoration in the YP region, and the methods used here could be applied to other lacustrine and coastal regions experiencing similar aquaculture activities.

From 3177 specimens of purple flying squid Sthenoteuthis oualaniensis collected in 2012 and 2013 in the central and southern South China Sea, the morphological indicators including mantle length (ML), arm length-I (AL1), arm length-2 (AL2), arm length-3 (AL3), arm length-4 (AL4), tentacle length (TL), fin length (FL) and fin width (FW) were measured. The morphological variations among the squid species were analyzed using principal component analysis. Results showed that the medium form could be distinguished into cohort I and cohort II which accounted for 69% and 31% of the total, respectively. The percentage of females of the two cohorts decreased first with increasing ML, then increased and reached the ratio of 100% finally. Using Logistic regressing, the MLs at first maturity for females and males of cohort I were estimated to be 164 mm and 112 mm, respectively, and those for females and males of cohort II were 158 mm and 109 mm, respectively. The cohort I concentrated in the waters of Xisha Islands and Nansha Islands, whereas the cohort II was located in the waters of Nansha Islands. Significant differences in all the 8 morphological indicators between either males or females of cohort I and cohort II were found (P＜0.05). Significant differences between cohort I and cohort II in ML, AL1, AL2, AL4, TL and FW were identified in females (P＜0.05), while significant differences between cohort I and cohort II in ML, AL1, AL2, AL3, AL4 and FL were found in males (P＜0.01). The analysis of coefficients of difference indicated that the morphological variations between cohort I and cohort II suggested a clear division within the species.
根据2012和2013年在南海中南部采集到的3177尾鸢乌贼中型群样品,对其胴长(ML)、右第一腕长(AL1)、右第二腕长(AL2)、右第三腕长(AL3)、右第四腕长(AL4)、右触腕长(TL)、鳍长(FL)和鳍宽(FW)等形态参数进行测定,并运用主成分分析等方法对其个体的形态差异进行研究.结果表明: 研究海域的鸢乌贼中型群可分为Ⅰ和Ⅱ 2个群体,分别占总数的69%和31%.2个群体的雌性比例均随胴长的增大呈先减少后增加的趋势,直至达到100%;群体Ⅰ雌性和雄性的初次性成熟胴长分别为164和112 mm,群体Ⅱ雌性和雄性初次性成熟胴长分别为157和108 mm.群体Ⅰ在西沙海域和南沙海域均有独立分布区域,而群体Ⅱ密集区主要分布于南沙海域.非参数检验表明:2个群体雌性和雄性个体的全部形态参数均存在显著性差异(P＜0.05).在雌性鸢乌贼中,群体Ⅰ和群体Ⅱ的ML、AL1、AL2、AL4、TL和FW存在显著性差异(P＜0.05);在雄性鸢乌贼中,群体Ⅰ和群体Ⅱ的ML、AL1、AL2、AL3、AL4和FL存在显著性差异(P＜0.01).通过计算差异系数表明,2个群体的形态差异处于种内水平.

Microplastics are emerging contaminants and have attracted widespread environmental concerns about their negative effects on the marine ecosystems. In this study, we investigated the abundances, distributions and characteristics of microplastics in surface seawater and sediments from the North Yellow Sea. The results showed that the abundance of microplastics was 545 ± 282 items/m3 in surface seawater and 37.1 ± 42.7 items/kg dry weight in sediments, representing a medium microplastic pollution level compared with other sea areas. Small microplastics (<1 mm) made up >70% of the total microplastic numbers. Films and fibers were the dominant shapes of microplastics in both the surface seawater and sediments. Transparent microplastics were generally more common than microplastics of other colors. Based on the identification by a Fourier transform infrared microscope, polyethylene (PE) was the dominant composition of microplastics in surface seawater, while polypropylene (PP) was the most common polymer type in sediments. These results will improve our understanding of the environmental risks posed by microplastics to marine ecosystems.