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Direct age determination of crustaceans has remained a long-standing challenge because all calcified structures are shed with each molt. Cuticle bands in the ossicles of the gastric mill have shown promise as age indicators. We validated the one-to-one relationship between known age and number of cuticle bands for 15 hatchery-raised juvenile American lobsters (Homarus americanus). Additionally, we applied this method to 308 lobsters from three contrasting thermal regimes in New England, USA. Band counts matched our expectations of differences in age-at-size across this thermal gradient; lobsters at harvestable size in southern New England were estimated to be 5.5 ([+ or -]1.5) years old compared with 7.5 ([+ or -] 1.6) years in the Gulf of Maine. We found 81% of our band count estimates of age fell within 2 years of independent, regionally specified growth model estimates of age-at-size for lobster. Notwithstanding remaining uncertainties regarding the mechanism of band formation, our findings indicate the method may provide an independent and direct means to determine the age of individual American lobsters, which will improve estimates of essential life history parameters. La determination directe de l'age de crustaces est un defi de longue date etant donne que toutes les structures calcifiees sont perdues a chaque mue. Des bandes cuticulaires dans les ossicules du moulin gastrique se sont averees prometteuses comme indicateurs de l'age. Nous avons valide la relation directe entre l'age connu et le nombre de bandes cuticulaires pour 15 homards (Homarus americanus) juveniles eleves en ecloseries. Nous avons de plus applique cette methode a 308 homards provenant de trois regimes thermiques distincts en Nouvelle-Angleterre (Etats-Unis). Le nombre de bandes concorde avec nos attentes quant aux differences d'age selon la taille le long de ce gradient thermique; l'age estime des homards ayant atteint la taille reglementaire dans le sud de la Nouvelle-Angleterre etait de 5,5 ans ([+ or -]1,5), comparativement a 7,5 ans ([+ or -]1,6) dans le golfe du Maine. Nous avons constate que 81% de nos estimations de l'age basees sur le nombre de bandes tombaient dans une fourchette de 2 ans autour des ages selon la taille estimes par des modeles de croissance en fonction de la region pour les homards. Bien que des incertitudes persistent concernant le mecanisme de formation des bandes, nos constatations indiquent que cette methode pourrait constituer un moyen independant et direct de determination de l'age de homards individuels, ce qui ameliorera les estimations de parametres cles de leur cycle biologique., Introduction Age determination is an essential tool in studies of the ecology and management of fish and invertebrate populations. The calcified skeletons of bony fishes, mollusks, and corals accumulate annual [...]

The Atlantic sea scallop fishery is the one of the most valuable fisheries in North America. There is concern about scallops with low-quality adductor muscles, referred to as gray meats, impacting the fishery and the overall health of the stock because an apicomplexan parasite has been linked to gray meats and a mass mortality event that led to the collapse of the Icelandic scallop fishery. Yet, changes in scallop meat color have also been linked to the depletion of energy reserves in the adductor muscle following spawning. Seasonal scallop dredge surveys were conducted across Georges Bank, collecting data on scallop meat quality, scallop abundance, mortality, and reproductive cycles, as well as environmental parameters, including bottom depth and temperature. To investigate multiple causes for gray meats, a set of models were developed to examine the impact of biotic and abiotic factors on gray meat prevalence and meat quality of individual scallops. Model results indicate that different factors influence gray meat prevalence on the southern and northern parts of Georges Bank. In the south, location was a significant factor for predicting the presence of gray meats, highlighting Closed Area I where an outbreak of gray meats occurred after the area reopened to fishing. Yet in the north, reproductive stage was a significant factor, with scallops more likely to have discolored meats after spawning. Study results suggest that gray meats may be a symptom of poor condition that was caused by multiple factors and isolating a single cause may not be possible. Improved screening tests and continued monitoring of scallop health through targeted disease surveys is recommended. KEY WORDS: apicomplexan parasite, gametogenesis, Georges Bank, scallop dredge, seasonal surveys, Placopecten magellanicus, INTRODUCTION The Atlantic sea scallop Placopecten magellanicus (Gmelin, 1791) fishery is the one of the most valuable fisheries in North America, with 2016 landings worth more than $488 million (NMFS [...]