Since 2017, a fishing moratorium has been enforced in Lake Honghu as part of Chang-Jiang’s biodiversity conservation strategy. However, given that the lake is a semi-closed aquatic ecosystem, and no longer serves as a habitat for certain fishes of the mid-lower Chang-Jiang basin, the efficacy of this moratorium remains uncertain. To address the question from a trophic ecology perspective, a stomach content analysis was performed on captured anchovies C. brachygnathus, a current predominant species in Lake Honghu, from November 2020 to October 2021. Results showed that copepods, shrimps, and macrophytes were the main components of this anchovy's diet, and had size-related shifts in diets. The dominance of C. brachygnathus, a pelagic-littoral omnivore in this lake, implies a lacustrine environment shift triggered by continued human disturbances. The utilization of macrophytes as the main food items by large-sized anchovies of Lake Honghu partially contributed to the rapid degradation of submerged vegetation. This highlights the need to remove large-sized individuals of C. brachygnathus and Carassius auratus, another benthic-omnivorous dominant fish, in order to effectively restore the aquatic vegetation and ecosystem of Lake Honghu. The current implementation of fishing moratoriums in subtropical shallow floodplain lakes such as Lake Honghu should be reviewed critically.

Anchovies are amid the largest fish catch worldwide. The anchovy fillet industry generates a huge amount of biowaste (e.g. fish heads, bones, tails) that can be used for the extraction of several potentially valuable bioproducts including omega-3 lipids. Following the extraction of valued fish oil rich in omega-3, vitamin D₃ and zeaxanthin from anchovy fillet leftovers using biobased limonene in a fully circular process, the solid residue was used as starting substrate for the production of biogas by anaerobic digestion. The results first reported in this study demonstrate good potential energy recovery of the anchovy sludge of about 280 mL_CH4∙g_VS^-1. Due to unbalanced C/N ratio typical of marine biowaste, co-digestion with a carbon rich substrate is recommended.

Fish oil rich in docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), vitamin D₃ and natural astaxanthin sustainably extracted from anchovy fillet leftovers using biobased limonene only, can be conveniently stabilized by adsorption on periodic mesoporous silicas. The simplicity of the process, the high load of entrapped fish oil, and the biocompatible nature of silica support numerous forthcoming applications of this new class of “Omeg@Silica” materials.

Fish oil rich in polyunsaturated omega-3 fatty acids is extracted in high yield from anchovy filleting waste using d-limonene as green biosolvent in a simple solid-liquid extraction performed by mechanically stirring and maceration followed by limonene removal via evaporation under reduced pressure. As limonene is renewably obtained from waste orange peel, this protocol establishes a circular bioeconomy method to obtain valued omega-3 extracts from biowaste available worldwide in several million t/year amount. The method closes the materials cycle and opens the route to full valorisation of an important biological resource so far mostly discarded as waste. Significant economic opportunities benefiting local communities, the ecosystem and public health are anticipated.

Humpback whales perform long migrations from their breeding and nursing areas at low latitudes to feeding grounds at high latitudes. Nonetheless this strictly dichotomous paradigm of migration is challenged by accumulating examples of occasional or regular feeding in tropical or subtropical areas for several stocks worldwide. Here we report multiple lines of evidence of IWC ‘Stock G’ humpback whales feeding in coastal waters at low latitudes of the Southeast Pacific Ocean. Lunge-feeding behavior was observed in Ecuador, while both lunge- and trap-feeding in pursuit of Peruvian anchovy was documented in northern Chile. Five records of substantial defecation in a key breeding ground in Ecuador also demonstrates local foraging. In addition mark-recapture analysis of one individual feeding at high and mid latitudes of Chile suggested potential site fidelity to two foraging areas. Whether these behaviors are novel due to changes in prey distribution, intensifying competition for food from a growing humpback whale population, or rather reflect vastly increased research effort in a poorly studied region, remains unknown. Further research into the feeding ecology of 'Stock G' should help reveal historic and potentially novel feeding grounds, prey composition and precise migration paths.

Forage fish are crucial to human nutrition, especially in developing countries. However, in these countries, most forage fish catches are used to make aquafeeds for aquaculture, which leaves only a small quantity for direct human consumption. This practice increases fish prices in local markets and undermines people's nutrition. Overfishing forage fish for industrial purposes harms the ecosystem, reduces the catch of larger fish, and marginalizes local fishermen. Although previous discussions have touched qualitatively on the ethics and injustice of this practice, this article provides quantitative scales to measure the impact of the practice on the finances and forage fish consumption of low-income consumers using reasonable assumptions and literature values. Increasing the annual supply of forage fish by 25% to the 5 million MT of fresh fish markets globally could save consumers several billion US dollars annually. Families could consume a higher percentage of nutritious fish for less money. Furthermore, leaving forage fish in the sea could benefit wildlife and increase the capture of larger fish, such as mackerel, which are in demand in local markets and fished by local fishermen. The unintentional and involuntary contributions of low-income societies to enable the growth of high-value fish and shrimp for affluent societies seem unjust and warrant further investigation.