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Our novel approach for fish age prediction uses quantitative analysis of Fourier transform near-infrared (FT-NIR) spectra of otoliths by means of multimodal convolutional neural networks (MMCNN). We integrate two key data modalities that are related to fish ages: the entire range of wavenumbers of FT-NIR spectra and corresponding biological and geospatial data for nearly 9000 walleye pollock (Gadus chalcogrammus) specimens. The proposed model extracts informative spectral features automatically and elucidates hidden structural relationships associated with fish growth to improve age predictions. Absorbance associated with 7000 to 4000 [cm.sup.-1] wavenumbers had the highest influence on model predictions followed by fish length, latitude, depth, and temperature. The optimal model resulted in good overall performance with an [R.sup.2] of 0.93 and RMSE of 0.83 for training data set and [R.sup.2] of 0.92 and RMSE of 0.91 for test data set. MMCNN's age predictions were comparable to microscope-based ages yielding as good or slightly better precision. Moreover, the model outperformed classical partial least squares analysis of otolith spectra and remedied prediction bias at older ages of fish. Key words: walleye pollock, otolith, fish age, near-infrared spectroscopy, convolutional neural network, deep machine learning, 1. Introduction For more than a century, marine and freshwater teleost fishes have been aged using otoliths, which are acellular calcium carbonate biominerals that grow in three dimensions throughout the [...]

Cutting-edge DNA methylation-based epigenetic aging techniques were applied to Gulf of Mexico northern red snapper (Lutjanus campechanus; n = 10; 1-26 years old) and red grouper (Epinephelus morio; n = 10; 2-14 years old). Bisulfiteconverted restriction site-associated DNA sequencing was used to identify CpG sites (cytosines followed by guanines) that exhibit age-correlated DNA methylation, and species-specific epigenetic clocks developed from hundreds of CpG sites in each species showed strong agreement between predicted and otolith-derived age [r.sup.2] > 0.99 for both species). Results suggest epigenetic age estimation could provide an accurate and efficient approach to mass-aging fishes in a non-invasive manner. Des methodes epigenetiques de pointe de determination de l'age reposant sur la methylation de l'ADN ont ete appliquees au vivaneau campeche (Lutjanus campechanus; n = 10; 1-26 ans) et au merou rouge (Epinephelus morio; n = 10; 2-14 ans). Le sequencage avec conversion au bisulfite d'ADN associe a des sites de restriction a ete utilise pour cerner des sites CpG (cytosines suivies de guanines) qui presentent une methylation de l'ADN correlee a l'age, et des horloges epigenetiques propres a l'espece developpees a partir de centaines de sites CpG de chaque espece ont revele de fortes concordances entre les ages predits et les ages obtenus par analyse d'otolites [r.sup.2] > 0,99 pour les deux especes). Les resultats donnent a penser que l'estimation epigenetique de l'age pourrait constituer une approche non invasive exacte et efficiente de determination des ages de quantites massives de poissons., Introduction Age data are fundamental to determining life history parameters (e.g., age-at-length, age-at-maturity, age-related fecundity) and are thus critical for fisheries assessment and management, particularly when age-structured stock assessment models [...]

We tested whether [DELTA][sup.14]C values of eye lens protein (crystallin) formed in early life could be utilized to validate marine bony fish age estimates via the bomb radiocarbon chronometer. The slope of the relationship between red snapper (Lutjanus campechanus; n = 8; 0 to 27 years old), otolith and eye lens core [DELTA][sup.14]C values was not significantly different than 1, which was also true for seven additional reef fish species (n = 21; 0 to 24 years old). Results demonstrate eye lens core [DELTA][sup.14]C can be utilized to validate age estimates of marine fishes, which will be useful in numerous age validation applications. Nous avons verifie si les valeurs de [DELTA][sup.14]C de la proteine du cristallin de l'oil (la cristalline) formee tot durant la vie pouvaient etre utilisees pour valider des estimations de l'age de poissons osseux marins par chronometrie au radiocarbone derive de bombes atomiques. La pente de la relation entre les valeurs de [DELTA][sup.14]C de cours d'otolites et de cristallins de vivaneaux rouges (Lutjanus campechanus; n = 8, ages de 0 a 27 ans) n'est pas significativement differente de 1, un resultat aussi observe pour sept autres especes de poissons de recifs (n = 21, ages de 0 a 24 ans). Ces resultats demontrent que le [DELTA][sup.14]C du noyau du cristallin peut etre utilise pour valider des estimations de l'age de poissons marins, ce qui sera utile dans de nombreuses applications de validation d'ages. [Traduit par la Redaction], Introduction The bomb radiocarbon ([sup.14]C) chronometer has been widely applied to validate age estimation in marine bony fishes. This approach relies on the approximate doubling of atmospheric [sup.14]C in the [...]

Many members of the scorpaenid subfamily: Sebastinae (rockfishes and their relatives) exhibit slow growth and extreme longevity (> 100 y), thus are estimated to be vulnerable to overfishing. Blackbelly rosefish (Helicolenus dactylopterus) is a deepwater sebastine whose longevity estimates range widely, possibly owing to different regional levels of fisheries exploitation across its Atlantic Ocean range. However, age estimation has not been validated for this species and ageing for sebastines in general is uncertain. We performed age validation of northern Gulf of Mexico blackbelly rosefish via an application of the bomb radiocarbon chronometer which utilized eye lens cores instead of more traditional otolith cores as the source of birth year Δ14C signatures. The correspondence of eye lens core Δ14C with a regional reference series was tested with a novel Bayesian spline analysis, which revealed otolith opaque zone counts provide accurate age estimates. Maximum observed longevity was 90 y, with 17.5% of individuals aged to be > 50 y. Bayesian growth analysis, with estimated length-at-birth included as a prior, revealed blackbelly rosefish exhibit extremely slow growth (k = 0.08 y−1). Study results have important implications for the management of blackbelly rosefish stocks, as extreme longevity and slow growth imply low resilience to fishing pressure. [ABSTRACT FROM AUTHOR]

Growth characteristics are poorly understood for speckled hind (Epinephelus drummondhayi), a tropical deep-water grouper of economic importance that is considered overfished. Age has been validated for early growth, but the validity of adult age estimates is unknown. A few studies of growth zones in otoliths have revealed maximum age estimates of 15-35 years, which have been uncritically assumed as longevity. To answer questions about adult age, bomb radiocarbon dating was used to provide validated age estimates. A novel aspect of this study was use of the postbomb radiocarbon decline period (ca. 1980- 2004) to age younger fish, an approach that was validated with known-age otoliths. Bomb radiocarbon dating provided valid length-at- age estimates ranging from ~5 years to more than 45 years. Age was unexpectedly greater than previous estimates for more than half the fish used in this study, and longevity may approach 60-80 years. This study extends the utility of bomb radiocarbon dating by more than 20 years and adds to the growing perspective that deep-water tropical fishes can be long-lived. Les caracteristiques de croissance ne sont pas bien comprises pour le merou grivele (Epinephelus drummondhayi), un poisson tropical d'eau profonde d'importance economique et considere comme etant surexploite. Des estimations de l'age ont ete validees pour le debut de la croissance, mais la validite des estimations de l'age d'adultes n'est pas connue. Quelques etudes des zones de croissance d'otolites ont donne des estimations de l'age maximum allant de 15 a 35 ans, dont il a ete presume sans evaluation critique qu'ils representaient la longevite. Pour repondre aux questions touchant a l'age des adultes, la datation au radiocarbone post-bombe a ete utilisee pour obtenir des estimations validees de l'age. Un aspect novateur de cette etude consiste en l'utilisation de la periode de diminution du radiocarbone post-bombe (ca. 1980-2004) pour determiner l'age de poissons relativement jeunes, cette approche ayant ete validee a l'aide d'otolites d'ages connus. La datation au radiocarbone post-bombe a fourni des estimations valides de la longueur selon l'age allant de ~5 ans a plus de 45 ans. Contrairement aux attentes, les ages se sont averes plus grands que les estimations anterieures pour plus de la moitie des poissons utilises dans l'etude, et la longevite pourrait etre de l'ordre de 60 a 80 ans. Cette etude elargit de plus de 20 ans la plage de temps pour laquelle la datation au radiocarbone post-bombe est utile et appuie la notion de plus en plus frequemment invoquee selon laquelle les poissons tropicaux d'eau profonde peuvent vivre tres longtemps. [Traduit par la Redaction], Introduction The speckled hind (Epinephelus drummondhayi), a tropical deepwater grouper (Family Epinephelidae) of economic importance in the western North Atlantic and Gulf of Mexico, was identified as a 'species of [...]

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