Mark A. Freeman

Crustacean shell disease, characterized by progressive degradation of the chitinous exoskeleton due to secretion of chitinases and other enzymes by microorganisms, has been reported in crustaceans worldwide. Diseases affect all natural populations to some extent. However, under normal circumstances, they are generally not in high prevalence. Disease epidemics are regularly experienced in various marine animals. Data on their causes is often scarce, at least partly due to limited or nonexistent baseline data on the prevalence and intensity of even the most common agents, under normal circumstances. This study presents the first description of shell disease in the non-indigenous Atlantic rock crab Cancer irroratus in Icelandic waters, a finding of significant concern. Between June and August from 2017 to 2023, a total of 5,818 C. irroratus were sampled in Hvalfjörður, SW-Iceland. The shell disease was assessed in relation to sex, and the pattern of infection on exoskeleton surfaces was described. The prevalence and severity of shell disease showed a concerning upward trend, with the infection rate increasing from 47% in 2017 to 85% in 2023. Samples taken from diseased crabs and subjected to histological, bacteriological and molecular analyses, revealed severe bacterial infections in lesions, composed of a mix of nine species of chitinolytic bacteria of five genera. Furthermore, a known pathogenic oomycete (fungal-like organism) was observed in all crabs examined. As in similar crustacean shell disease studies, the condition in C. irroratus from Icelandic waters appears to result from synergistic effects of various bacterial species, possibly exacerbated by the observed oomycete pathogen. However, the cause of an epidemic like this is unknown and can only be speculated on with current knowledge.

The Apicomplexa are obligate unicellular parasites found in terrestrial and aquatic environments. Nematopsis are found infecting marine invertebrates in a life cycle involving mollusks and crustaceans. In the present study, mantle and muscle tissues from nerite gastropods were microscopically examined for Nematopsis using wet mounts and histology. Oocysts contained one single sporozoite surrounded by an ellipsoidal wall and were surrounded by a parasitophorous vacuole within a host phagocyte. Length and width of fresh oocysts were measured and compared between host species. DNA was extracted from infected tissue, and regions of the rRNA gene were amplified using novel primers. Nematopsis‐infected tissues from scallops from Argentina and Scotland were used as controls. The sizes of oocysts observed in nerite hosts from Saint Kitts were not significantly different. DNA sequences of Nematopsis isolated from nerite hosts in this study were identical and phylogenetically related to sequences obtained from scallops. Bayesian and maximum likelihood phylogenetic analyses robustly place the Nematopsis DNA sequences from this study with Nematopsis from scallops in Florida and members of the family Porosporidae. We conclude that marine Nematopsis will group within this clade or within the Porosporidae. We have provided specific oligonucleotide primers to assist with the molecular study of the Porosporidae.

Across the tree of life, DNA damage response (DDR) proteins play a pivotal, yet dichotomous role in organismal development and evolution. Here, we present a comprehensive analysis of 432 DDR proteins encoded by 68 genomes, including that of Nucleospora cyclopteri, an intranuclear microsporidia sequenced in this study. We compared the DDR proteins encoded by these genomes to those of humans to uncover the DNA repair-ome across phylogenetically distant eukaryotes. We also performed further analyses to understand if organismal complexity and lifestyle play a role in the evolution of DDR protein length and conserved domain architecture. We observed that the genomes of extreme parasites such as Paramicrocytos, Giardia, Spironucleus, and certain microsporidian lineages encode the smallest eukaryotic repertoire of DDR proteins and that pathways involved in modulation of nucleotide pools and nucleotide excision repair are the most preserved DDR pathways in the eukaryotic genomes analysed here. We found that DDR and DNA repair proteins are consistently longer than housekeeping and metabolic proteins. This is likely due to the higher number of physical protein–protein interactions which DDR proteins are involved. We find that although DNA repair proteins are generally longer than housekeeping proteins, their functional domains occupy a relatively smaller footprint. Notably, this pattern holds true across diverse organisms and shows no dependence on either lifestyle or mitochondrial status. Finally, we observed that unicellular organisms harbour proteins that are tenfold longer than their human homologues, with the extra amino acids forming interdomain regions with a clearly novel albeit undetermined function.

Although sharks are important for marine ecosystems, they still suffer culling campaigns after human fatalities. A case study from the Caribbean shows how the rapid use of several complementary and reproducible forensic techniques not only allowed the confirmation of the species implicated in the bite but also the accurate assessment of the size of the animal. Six non‐lethal fishing sessions led to the capture of several shark individuals that were released after either being eliminated due to their unsuitable size or the absence of human remains in their stomach. Such an ecologically responsible risk management can contribute to shark conservation.

It is widely accepted that populations of terrestrial predators sometimes contain “problem individuals” that repeatedly attack humans, yet this phenomenon has never been demonstrated in sharks. Here, we present photographic and genetic evidence of individuals in populations of tiger Galeocerdo cuvier and oceanic whitetip Carcharhinus longimanus sharks that (1) demonstrated atypical behavior compared to the rest of the population, (2) engaged in repeated agonistic behavior directed toward humans, and (3) bit, or attempted to bite humans in probable foraging attempts. These case studies provide some of the first evidence for the existence of “problem individuals” among sharks. The percentage of fatalities due to the same shark individual are not known, so we recommend systematic swabbing of shark bite victims wounds to better understand the importance of this phenomenon and the possibility of identifying these animals. Environmentally conscientious management options for problem individuals range from prohibiting ocean activities (e.g., swimming and surfing) in their habitats to selectively removing the individual, although the latter would be challenging in the marine environment.

"Diving off the veterinary campus to study a highly contagious marine epidemic" published on 01 Jan 2024 by American Veterinary Medical Association.

ExtractMark Freeman Mark Freeman is Distinguished Professor of Ethics and Society in the Department of Psychology at the College of the Holy Cross in Worcester, Massachusetts. His research interests include narrative psychology, the psychology of memory and identity, theoretical and philosophical psychology, and the emerging field of the psychological humanities. His most recent books are Hindsight: The Promise and Peril of Looking Backward (2010) , The Priority of the Other: Thinking and Living Beyond the Self (2014) , and Do I Look at You with Love? Reimagining the Story of Dementia (2021) . The title of this essay refers to Wallace Stevens’ (1923) poem ‘Sunday Morning,’ when he writes of death as ‘the mother of beauty’. (Stevens 1997 [1923]: 55) Death is the mother of beauty, mystical, Within whose burning bosom we devise Our earthly mothers waiting, sleeplessly. A related idea may be found in Freud’s (1957 [1915]) brief meditation,...

Scrivener C. Scrivener. The Depopulation of Villages: An Address to the Trade Unionists on the Influx of Population to Towns, with a Proposal for Its Abatement (London: W. Heeves. 1891)

J. Theodore Dodd, Local Rights and Interests of Farm Labourers, 2nd edn (London: National Press Agency Limited, [1890])