Over the span of a decade, genetic identification methods have progressively exposed the inadequacies of the seafood supply chain, revealing previously unrecognized levels of seafood fraud, raising awareness among the public, and serving as a warning to industry that malpractice will be detected. Here we present the outcome of the latest and largest multi‐species, transnational survey of fish labeling accuracy to date, which demonstrates an apparent sudden reduction of seafood mislabeling in Europe. We argue that recent efforts in legislation, governance, and outreach have had a positive impact on industry regulation. Coordinated, technology‐based, policy‐oriented actions can play a pivotal role in shaping a transparent, sustainable global seafood market and in bolstering healthier oceans.

Recreational sea angling is an important recreational activity in the United Kingdom with around 1.6% of adults participating and a total economic impact of around £1.5 billion each year. There are positive impacts of angling on physical health and mental well-being. The COVID-19 pandemic resulted in several national lockdowns in the UK, which along with additional local restrictions and personal circumstances due to the pandemic, have impacted people’s ability to fish. Angling was not allowed in the UK for some of the first lockdown (March to May 2020), and further restrictions were implemented subsequently that varied between the countries and regions. The impact of COVID-19 on the participation, effort, physical activity, and well-being of UK sea anglers remains unknown. A panel of UK sea anglers, which record their activity and catches as part of the Sea Angling Diary Project, were surveyed to assess changes in sea angling participation, physical activity, mental well-being, and expenditure between 2019 and 2020. We compared the sea angling effort and catches of the diary panel between 2019 and 2020. We found reduced sea angling effort in the panel, including sessions and catches, between 2019 and 2020, with the largest impact being in April 2020. We found that there was a significant reduction in expenditure during April 2020 with 64% of respondents spending less on sea angling than in a typical April. In total, 67% of respondents reported reduced happiness and 45% were less active due to sea angling restrictions. Using a general linear model, we found that even though anglers said that being able to go fishing has resulted in high World Health Organization Five Well-being Index scores, other factors also had significant effects. These included: age; physical and mental health status; angling activity; travel to fish during COVID-19; and whether they fished in July 2020. Of those who responded, 66% classified themselves as at either high or moderate risk to COVID-19. This work has shown that COVID-19 has negatively affected marine recreational fisheries in the UK, and not being able to go sea angling has negatively impacted participation, effort, physical activity and well-being.

Eighteen captive small‐spotted catsharks Scyliorhinus canicula were successfully identified from hatching to 1 year of age using the free computer recognition software, I3S classic. The effect of increasing the time interval between recognition attempts on the accuracy of the software was investigated, revealing that recognition fiedelity decreases with increasing time intervals for younger (0 to 15 weeks), but not older (15 weeks onwards) sharks. Identification by I3S was validated using genetic analyses of seven microsatellite markers, revealing a 100% success rate. Thus, this non‐invasive recognition method can be used as an inexpensive and effective alternative to invasive tagging, improving animal welfare and complementing ex‐situ conservation methods.

Elasmobranchs display various reproductive modes, which have been key to their evolutionary success. In recent decades there has been a rise in the number of reported cases of foetal abnormalities including fertilised, double-embryos held within one egg capsule, hereafter referred to as twins. Previously, the occurrences of twin egg cases have been reported in two batoid and one shark species. We report the first cases of twins in three species of oviparous elasmobranchs: the undulate ray (Raja undulata), the nursehound (Scyliorhinus stellaris), and the small-spotted catshark (Scyliorhinus canicula). We investigated the genetic relationships between the twins in S. stellaris, and S. canicula using microsatellite markers. Whilst the S. stellaris twins displayed the same genotypes, we found that the S. canicula twin individuals arose through heteropaternal superfecundation. This is the first reported incidence of such a paternity in elasmobranchs. The relationship between environmental change and reproductive strategy in elasmobranchs is unclear and further research is needed to determine its effect on the prevalence and mechanisms of formation of elasmobranch twins.

Exposure to elevated temperatures during embryogenesis has profound acute effects on the cardiac performance, metabolism, and growth of fishes. Some temperature-induced effects may be retained into, or manifest in, later-life through a mechanism termed developmental programming. In this study, we incubated Scyliorhinus canicula embryos at either 15°C or 20°C before transferring the newly hatched sharks to a common set of conditions (15°C) for 5 months. Lasting transcriptomic differences associated with the developmental environment were identified, and interactions between cardiac genes were investigated using hypernetwork modelling. Development at an elevated temperature caused changes in transcriptomic connectivity and entropy, parameters thought to relate to plasticity and fitness. We then validated these observations through a novel re-analysis of published Danio rerio and Dicentrarchus labrax muscle tissue datasets. Together, these data demonstrate a persistent, programmed effect of developmental temperature on the co-ordination of gene expression in three species of fishes, which may relate to altered plasticity and fitness in later-life.