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The paper adopts the bootstrap procedures proposed by Simar and Wilson for data envelopment analysis to analyze technical efficiency in aquaculture. The data of 318 intensive shrimp farming households in the south-central coast of Vietnam is used as a case for analysis. The result demonstrates that the null hypothesis of constant returns-to-scale is rejected in favour of variable returns-to-scale for the production technology.Moreover, the potential improvement is certainly greater using bootstrapping than that using the conventional data envelopment analysis, which has been adopted widely in the aquaculture literature for technical efficiency estimation. By adopting the double bootstrap proposed by Simar & Wilson (2007), the bias-corrected technical efficiency is 0.69, and at the 95% confidence interval with the lower limit of 0.65 and the upper limit of 0.75. In addition, factors that might statistically positive influence technical efficiency in this farming are larger farm size, having access to formal credit; whereas negative influences are cultural length.

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Climate change is having a significant impact on the biology and ecology of fish stocks and aquaculture species and will affect the productivity within seafood supply chains in the future. The challenges are further amplified when actors within the fisheries and aquaculture sectors have very different ideas and assumptions about climate change and what risks and opportunities they entail. In order to address the challenges of climate change, several countries have developed national adaptation plans. However, fisheries and aquaculture are rarely included in these plans, resulting in a general lack of documented adaptation strategies within these sectors in most countries. This paper introduces guidelines for the development of climate adaptation plans (CAPs) within fisheries and aquaculture, applying a co-creation approach that requires the participation of scientists, industry representatives, policymakers, and other relevant stakeholders. The objective is to provide a stepwise approach to facilitate and enable stakeholders to plan strategies toward climate adaptation. The guidelines are based on practical experience and include a three-step process: (1) assessment of risks and opportunities; (2) identification of adaptation measures, and (3) operationalization of CAPs. The three-step process is also part of a larger cycle, including implementation, monitoring, and evaluation, again generating iterative feedback loops over time. Lessons learned are discussed, and we highlight the advantages and challenges of developing CAPs. While the guidelines are designed for and tested within fisheries and aquaculture systems, the CAP approach is also employable for other natural resource-based systems.

This study discusses and estimates the backward-bending supply curve, using data for three years over a six-year time span from the inshore purse seine fishery in Khanh Hoa province, Vietnam. Four different models are developed for estimation based on fisheries data, in the absence of stock survey data. The estimated maximum sustainable yield for the anchovy in south-central Vietnam ranges from 138 thousand tons to 293 thousand tons. The results reveal that the anchovy stock to some extent is biologically over-exploited, but seems to have rebuilt in recent years. For management it makes sense to use available, cheaply collected fisheries data on harvests, prices and costs, if biological surveys are lacking, which is often the case due to the cost of establishing expensive research capacities and time series.

Remote sensing technology nowadays is one of the most useful tools for scientific research in general and for oceanography in particular. From satellite images, the useful information such as waterline images can be extracte for a large region simultaneously. After tidal adjustments, the waterlines can be used as the observed shorelines which are important inputs for estimating shoreline changes by either using the integration of remote sensing and GIS or using numerical models. Based on the spectral bands of various Landsat images, the paper presents the methods to detect the waterlines in Phan Thiet region in the 40 years period using the images of 1973, 1976, 1990, and 2002 respectively. The extracted results relatively agree with the information of waterline from the images.

Deep neural networks (DNNs) have made outstanding achievements in a wide variety of domains. For deep learning tasks, large enough datasets are required for training efficient DNN models. However, big datasets are not always available, and they are costly to build. Therefore, balanced solutions for DNN model efficiency and training data size have caught the attention of researchers recently. Transfer learning techniques are the most common for this. In transfer learning, a DNN model is pre-trained on a large enough dataset and then applied to a new task with modest data. This fine-tuning process yields another challenge, named catastrophic forgetting. However, it can be reduced using a reasonable strategy for data argumentation in incremental learning. In this paper, we propose an efficient solution for the random selection of samples from the old task to be incrementally stored for learning a sequence of new tasks. In addition, a loss combination strategy is also proposed for optimizing incremental learning. The proposed solutions are evaluated on standard datasets with two scenarios of incremental fine-tuning: (1) New Class (NC) dataset; (2) New Class and new Instance (NCI) dataset. The experimental results show that our proposed solution achieves outstanding results compared with other SOTA rehearsal methods, as well as traditional fine-tuning solutions, ranging from 1% to 16% in recognition accuracy.

Subsidies are part of the set of management tools that governments apply to modernize their fishing fleets and enable them to engage in offshore and international fisheries. Research has shown that subsidies often lead to overcapacity and overfishing, resulting in the depletion of fish stocks. A few studies have, however, found some positive effects for particular subsidies.In this paper, we investigate a credit-linked subsidy scheme in Vietnam, which seems to be justified on the basis of economic, social, and environmental considerations. Both propensity score matching and endogenous switching regression methods are employed for analysis. The results show that the subsidies have had a positive effect on fishermen's profitability, mainly due to increased revenue rather than cost reduction. However, the subsidies have benefited only the owners of the biggest vessels, and inefficiency in subsidized vessels may threaten resources and profitability in the long term.