The last five years have been extremely challenging, but also very innovative for cephalopod science, and the outstanding tradition of biological contribution with cephalopod molluscs as key players in science and human activities and interests has continued. This Research Topic is one of several dedicated to cephalopod molluscs (e.g., Hanke and Osorio, 2018; Ponte et al., 2018) hosted by Frontiers over the last few years, not to mention other papers published separately. Highlighting of cephalopod science is important because it has much to offer not only the life science community, but also more broadly the public perception of science and its understanding and relationship with scientific endeavour and cephalopods as living organisms and part of our everyday life (at least for most of us). This contribution illustrates the key needs that need to be overcome by the cephalopod research community, i.e. rapid and effective mechanisms for exchange of knowledge and resources, sharing of laboratory protocols, videos, tissues, samples and data-sets, innovative approaches and initiatives in public engagement. The cuttlefish comic included is an excellent example of a type of media that can be used to expand scientific knowledge to the public and human relationship with live animals. There are strategic challenges in convincing globally distributed policy makers and funders of the relevance of cephalopods in scientific advances, and also in the regulatory aspects, since cephalopods are the only invertebrates whose use is regulated in Europe in a research context and this increases the need for integrated oversight and direction in terms of ethics and animal welfare (e.g., Jacquet et al., 2019a; 2019b; Ponte et al., 2019). This Research Topic also aligns with the interests of the cephalopod community in stimulating public interest in cephalopods extending to a broader audience that could include chefs and gourmets, and fishers and scientists aiming to develop sustainable food resources. “CephsInAction: Towards Future Challenges for Cephalopod Science” Research Topic includes 14 papers from about 40 authors representing ten different countries, thus overlapping with the original parties that contributed to the COST FA1301 that, together with CephRes, promoted and supported this editorial initiative.

Humans everywhere have always been fascinated by octopuses, squid, and cuttlefish, known biologically as cephalopods. They evolved hundreds of millions of years ago and are related to molluscs such as mussels and snails. They can grow to an enormous size with eyes as big as footballs, but they still live for only a couple of years. They mate once in their lifetime and die shortly after. They have blue blood and three hearts and they can shoot out jet-black ink. They have a brain and have behaviours that could be interpreted as signs of intelligence, even though more than half of their brain is distributed in their arms. They are colour blind, but they can change the colour of their skin in a flash. They are masters of disguise and are able to alter the texture of their skin and the patterns displayed on it at lighting speed. They can also ‘taste’ using the suckers on their arms. They can move extremely fast thanks to a jet-propulsion system built into their body cavity. Although they are soft-bodied and look vulnerable, cephalopods are formidable predators. Octopuses have arms that are so strong that they can exert a force equal to hundreds of times their own body weight. Squid and cuttlefish can shoot out a tentacle to capture prey at the speed of a javelin thrown by an expert athlete. Cephalopods are, however, so much more than just fascinating creatures with strange physical characteristics. They are a nutritious, delicious protein source that has found a place for thousands of years in many food cultures around the world. As squid, cuttlefish, and octopuses are native to virtually all parts of the ocean, they are an excellent and available alternative to meat from terrestrial animals. This book is written to promote the overall place of cephalopods in home kitchens and to inspire the uninitiated to add them to their diet. It describes the many facets of their anatomy that play a central role in their potential use as healthy, diverse, and interesting food sources, with a particular emphasis on their taste and texture. By way of an assortment of recipes, the authors hope to dispel the myth that it is difficult to prepare delicious dishes using squid, cuttlefish, and octopuses. In addition, there are contributions to the on-going discussions about how marine resources can be exploited more responsibly in a sustainable manner. Ole G. Mouritsen is a professor of gastrophysics and culinary food innovation at the University of Copenhagen,president of the Danish Gastronomical Academy, and director of the Danish national research and communication centre Taste for Life. Klavs Styrbæk is a chef and leader of the gastronomic enterprise STYRBÆKS, which includes a gourmet restaurant, a cooking school, a catering service, and a product development branch.

Cephalopods usually have large and mobile eyes with which they constantly scan their environment. The eyes of cephalopods are single-chamber eyes which show resemblance to vertebrate eyes. However there are marked differences such as the cephalopod eye having an everted retina instead of an inverted retina found in vertebrates. Their visual system allows the cephalopods, depending on species, to discriminate objects on the basis of their shapes or sizes, images from mirror images or to learn from the observation of others. The cephalopod visual system is also polarization sensitive and controls camouflage, an extraordinary ability almost exclusive to all cephalopods; they are capable of rapidly adapting their body coloration as well as altering their body shape to any background, in almost any condition and even during self-motion. Visual scene analysis ultimately leads to motor outputs that cause an appropriate change in skin coloration or texture by acting directly on chromatophores or papillae in the skin. Mirroring these numerous functions of the visual system, large parts of the cephalopod brain are devoted to the processing of visual information. This research topic focuses on current advances in the knowledge of cephalopod vision. It is designed to facilitate merging questions, approaches and data available through the work of different researchers working on different aspects of cephalopod vision. Thus the research topic creates mutual awareness, and facilitates the growth of a field of research with a long tradition - cephalopod vision, visual perception and cognition as well as the mechanisms of camouflage. This research topic emerged from a workshop on “Vision in cephalopods” as part of the COST Action FA1301.

The aim of this open access book is to facilitate the identification and description of the different organs as well as pathogens and diseases affecting the most representative species of cephalopods focussed on Sepia officinalis, Loligo vulgaris and Octopus vulgaris. These species are valuable ‘morphotype’ models and belong to the taxonomic groups Sepioidea, Myopsida and Octopoda, which include most of the species with a high market value and aquaculture potential. The study is based on photographs at macroscopic and histological level in order to illustrate the role of the most important pathogens and related diseases from the view of a pathological diagnosis. The reader is able to familiarize with functional anatomy, necropsy and general histology of adults and paralarvae, as well as with the identification of different pathogens and pathologies. This work is thus an invaluable guide for the diagnosis of cephalopod diseases. Besides including pathogens for non-European cephalopod species, it also provides a useful contribution encouraging marine pathologists, parasitologists, veterinarians and those involved in fishery sanitary assessments, aquarium maintenance and aquaculture practices aiming to increase their knowledge about the pathology of cephalopods.

For almost a century and a half, biologists have gone to the seashore to study life. The oceans contain rich biodiversity, and organisms at the intersection of sea and shore provide a plentiful sampling for research into a variety of questions at the laboratory bench: How does life develop and how does it function? How are organisms that look different related, and what role does the environment play? From the Stazione Zoologica in Naples to the Marine Biological Laboratory in Woods Hole, the Amoy Station in China, or the Misaki Station in Japan, students and researchers at seaside research stations have long visited the ocean to investigate life at all stages of development and to convene discussions of biological discoveries. Exploring the history and current reasons for study by the sea, this book examines key people, institutions, research projects, organisms selected for study, and competing theories and interpretations of discoveries, and it considers different ways of understanding research, such as through research repertoires. A celebration of coastal marine research, Why Study Biology by the Sea? reveals why scientists have moved from the beach to the lab bench and back.