Age, growth, maturity, and mortality of the Alaska skate, Bathyraja parmifera, in the eastern Bering Sea

The Alaska skate, Bathyraja parmifera, is the most abundant species of skate on the eastern Bering Sea shelf, accounting for over 90% of total skate biomass. However, little is known regarding the life history of this species despite its common occurrence as bycatch in several Bering Sea fisheries. This is the first study to focus on the age and growth of B. parmifera. From 2003 to 2005, more than one thousand specimens were collected by fisheries observers and on scientific groundfish surveys. Annual banding patterns in more than 500 thin sections of vertebral centra were examined for age determination. Caudal thorns were tested as a potentially non-lethal ageing structure. Annual band pair deposition was verified through edge and marginal increment analyses. A three-parameter von Bertalanffy growth function and a Gompertz growth function were fit to observed length-at-age data. Both models provided significant fits, although the Gompertz function best described the overall pattern of growth in both males and females, based upon statistical criteria and parameter estimates. Age and size at 50% maturity were 9 years and 92 cm TL for males and 10 years and 93 cm TL for females. The maximum observed ages for males and females were 15 years and 17 years, respectively. Estimates of natural mortality (M) ranged from 0.14 to 0.28, and were based on published relationships between M and longevity, age at maturity, and the von Bertalanffy growth coefficient. Due to these life history characteristics and a lack of long-term species-specific stock data, a conservative management approach would be appropriate for B. parmifera.     

The potential use of caudal thorns as a non-invasive ageing structure in the thorny skate (Amblyraja radiata Donovan, 1808)

The thorny skate, Amblyraja radiata, is the most widely distributed and abundant of all skate species worldwide, found on both sides of the north Atlantic Ocean. Large inter-regional size differences exist for this species and the few age and growth studies undertaken have revealed marked differences in life history traits for geographically distinct stocks. To facilitate the progression of further age and growth studies for this commercially important species, the effectiveness of caudal thorns as a rapid ageing tool was assessed. Twenty-eight male and 24 female thorny skates were collected off Greenland, covering the full size range of the species. Replicate age readings of crystal violet stained vertebral sagittal sections and whole silver nitrate stained caudal thorns revealed mean intra-reader age reading precision was higher for caudal thorns (Covariance (CV): reader 1 = 9.07, reader 2 = 9.73) than vertebrae (CV: reader 1 = 14.91, reader 2 = 14.27). Age bias plots revealed minimal inter-structure bias, apart from a higher average thorn age reading of 0.76 years from age classes 5–11 years for reader 1. Minor inter-reader bias was evident for vertebrae only; averaging 0.90 years higher for reader 1 from age classes 11 to 15 years. Preliminary evidence suggests caudal thorns could prove an effective non-invasive ageing tool for thorny skates.     

Reproductive biology of skates, Bathyraja(Ishiyama), along the eastern Bering Sea continental slope

Eight Bathyraja skate species, Bathyraja aleutica, Bathyraja interrupta, Bathyraja lindbergi, Bathyraja maculata, Bathyraja minispinosa, Bathyraja parmifera, Bathyraja taranetzi and Bathyraja trachura, collected along the eastern Bering Sea continental slope were examined for reproductive features. The sex ratio for six of eight Bathyraja skate species studied was c. 1 : 1 with males dominating for B. interrupta and B. parmifera. Five of eight species examined, B. aleutica, B. lindbergi, B. parmifera, B. taranetzi and B. trachura approximately equalled or exceeded the maximum reported total length, L_T. Maximum L_T for three species (B. interrupta, B. minispinosa and B. parmifera) revealed that the largest individuals were males and that in three other species (B. lindbergi, B. maculata and B. trachura) both females and males grew to approximately the same size. Both females and males matured at approximately the same L_T for seven of eight species. Only female B. aleutica matured at a much larger size than males. All species matured within a narrow size range following a protracted juvenile stage and once mature these skates appeared to grow very little. First maturity for all species occurred at ≥80% of their maximum L_T. The number of oocytes did not significantly differ between the left and right ovary for any species. The total number of mature oocytes increased with L_T for six of eight species examined. The number of oocytes for one species, B. aleutica, increased in number until 145 cm L_T, then declined in those individuals greater in length. The egg cases of all species are described, of which four (B. lindbergi, B. parmifera, B. taranetzi and B. trachura) have never been previously reported. Evidence is presented that suggest skates may be limited to as little as one and as many as 13 spawning seasons, depending on the species, and that senescence may occur in older individuals.     

Age and growth characteristics of the Starry Skate,Raja stellulata,with a description of life history and habitat trends of the central California,U.S.A., skate assemblage

Skates are prevalent in fisheries worldwide, but rarely are they identified to species. This is of conservation and management concern since skates exhibit a broad range of life history characteristics. The present study investigated the age and growth of the Starry Skate, Raja stellulata, and compared it to other regional skates inhabiting the U.S. West Coast. Age and growth parameters were determined using two vertebral preparation techniques: gross sectioning and histological sectioning. Gross section age estimates ranged from zero to 11 years and growth was described by the two parameter von Bertalanffy growth function (2 VBGF; L _∞ ?=?915 mm total length (TL) and k?=?0.13 year^-1; n?=?189). Histological section age estimates ranged from zero to 15 years and growth was also described by the 2 VBGF (L _∞ ?=?1092 mm TL, k?=?0.06 year^-1; n?=?68). Histological section results reflect a more conservative life history, specifically a lower von Bertalanffy growth coefficient, but had slightly biased results and a smaller sample size than the gross section results. An age and depth trend was found within the central California skate assemblage, in which habitat depth and maximum age were positively correlated.     

Age and size at sexual maturity for the winter skate, <Emphasis Type="Italic">Leucoraja ocellata</Emphasis>, in the western Gulf of Maine based on morphological,histological and steroid hormone analyses

Synopsis We determined age and size at sexual maturity in male and female winter skates, Leucoraja ocellata, from the western Gulf of Maine. Age estimated from vertebral band counts resulted in an Index of Average Percent Error (IAPE) of 5.6%, suggesting that this method represents an accurate approach to the age assessment of L. ocellata. Size at sexual maturity was assessed by evaluating three endpoints: steroid hormone concentrations, and morphological and histological criteria. Our results suggest that 50% maturity in males occurs at a total length of 730 mm and at 11 years of age. For females, our results suggest that 50% maturity occurs at a total length of 760 mm and between 11 and 12 years of age. Collectively, our study suggests that analyzing a combination of reproductive parameters offers an accurate estimation of sexual maturity in the winter skate. Moreover, our results indicate that L. ocellata is a late-maturing and long-lived species, characteristics which make it highly susceptible to over-exploitation by commercial fisheries.     

An investigation on the effect of photoperiod and temperature on vertebral band deposition in little skate Leucoraja erinacea

An investigation was undertaken to determine whether photoperiod or temperature have an effect on the timing of vertebral opaque–transluscent band‐pair deposition in captive young‐of‐the‐year (YOY) little skate Leucoraja erinacea. The experimental design consisted of a randomized complete block split plot design with two factors: temperature and light. Temperature was nested within light and therefore four variables were tested: 1) constant light, 2) constant temperature, 3) seasonal light and 4) seasonal temperature. For 18 months, L. erinacea experienced accelerated seasonal conditions of temperature and light to mimic 3 years of growth. This study provides primary and supporting evidence that seasonal photoperiod and temperature, respectively, have no effect on timing of vertebral band‐pair deposition in captive L. erinacea. Vertebral analysis of surviving L. erinacea (n = 6, time = 18 months) showed that all produced 1–1·5 band pairs, while centrum edge analysis (n = 56) showed timing of winter and summer band deposition were similar regardless of treatment. The winter band (translucent) appeared in February 2007 and January 2008 while the summer band (opaque) showed up in July for both 2007 and 2008 and mimicked patterns observed in the wild. While temperature and photoperiod appear to have no effect on timing of band‐pair deposition in YOY L. erinacea, other mechanisms which may influence band deposition should be investigated including the effect of food ration and the presence of a circa‐annual rhythm and hormone secretion.     

Age,growth, and age at sexual maturity of the commercially landed skate species,Dipturus chinensis (Basilewsky, 1855), in the northern East China Sea

Age, growth, and age at sexual maturity of the polkadot skate Dipturus chinensis, in the northern East China Sea were determined for a total of 614 specimens collected from April 2009 to December 2014. Vertebral centrum analysis was used to calculate the age of the skates. Annual band deposition was determined by marginal increment analysis. The von Bertalanffy growth model was fitted to the observed length‐at‐age data for each sex (males, L_∞ = 76.8, k = 0.109, t₀ = ?1.28; females, L_∞ = 83.1, k = 0.103, t₀ = ?1.20). Growth patterns of females and males were similar until the age of 6; thereafter, females grew larger than males. Maximum age recorded was 13 years for males and 15 years for females. Age at 50% sexual maturity was 8.22 years for males and 9.39 years for females. These results indicate that D. chinensis is slow growing, relatively long‐lived, and late maturing, and therefore vulnerable to exploitation.     

BIASES IN DOLPHIN AGE STRUCTURE DUE TO AGE ESTIMATION TECHNIQUE1

The use of different tooth-preparation techniques resulted in widely different estimates of age in a sample of bottlenose dolphins, Tursiops truncatus. Teeth from 30 animals were prepared using the two most prevalent techniques reported in the literature for this species, unstained sections and decalcified and stained thin sections, and the resulting paired counts of growth layers were compared. Estimates from the two methods were identical or at least placed the specimen in the same age class in only five cases, ranging in age from 2 to 22 yr. Otherwise, the results fell into one of two categories: when the estimates were close (± 3-yr difference, n= 15), counts from unstained sections generally were higher (13 cases, age from unstained sections 2-20 yr); when the counts were more disparate, estimates from stained sections always were higher (6-31 yr difference, n= 10, age from unstained sections 12-27 yr and corresponding ages from stained sections of 27-47). Previous studies of age estimation in known-age bottlenose dolphins indicate that stained sections allow accurate estimates of age and demonstrate that maximum lifespan approaches or exceeds 50 yr. In contrast, the results herein suggest that using unstained sections for age estimation may result in imprecise or biased age-structure data.     

Age and growth of grey triggerfish Balistes capriscus from trans-Atlantic populations

Anthropogenic factors that negatively impact reef fishes can include changes in life-history patterns of fisheries-targeted species. Understanding these impacts on growth and population age structure is essential in the management of exploited populations of fishes. This is the first study to directly compare age and growth for a major fisheries species between east and west populations of a transatlantic reef fish. The main goal of this study was to document age and growth in grey triggerfish Balistes capriscus from coastal waters of Ghana in the Gulf of Guinea (GOG) and compare those with the previous growth studies from that region and with the western Atlantic population. A secondary objective of this study was to evaluate the use of otoliths to age triggerfish and to provide a preliminary comparison with spine-derived age estimates. The results obtained from this study provided an updated understanding of the growth and age structure of the eastern B. capriscus population in GOG. The authors documented that shifts in population attributes occurred for B. capriscus after its major decline in abundance. The differences in physical and biotic characteristics of the East and West Atlantic regions and the differences in collection methods of samples make direct comparisons of growth parameters difficult. Nonetheless, overall differences in maximum sizes and ages were apparent; the western Atlantic population had a larger maximum size and older maximum age. The authors also documented that sagittal otoliths can be used to provide age estimates for triggerfish species, and otoliths as an ageing structure had better between-reader precision compared to dorsal spines.     

Age,growth and maturity of the pelagic thresher Alopias pelagicus and the scalloped hammerhead Sphyrna lewini

Indonesia has the greatest reported chondrichthyan catches worldwide, with c.110,000 t caught annually. The pelagic thresher (Alopias pelagicus) and scalloped hammerhead (Sphryna lewini) together comprise about 25% of the total catches of sharks landed in Indonesia. Age and growth parameters were estimated for A. pelagicus and S. lewini from growth‐band counts of thin‐cut vertebral sections. Alopias pelagicus (n = 158) and S. lewini (n = 157) vertebrae were collected from three Indonesian fish markets over a 5 year period. A multi‐model analysis was used to estimate growth parameters for both species. The models of best fit for males and females for A. pelagicus was the three‐parameter logistic (L_∞ = 3169 mm L_T, k = 0·2) and the two‐parameter von Bertalanffy models (L_∞ = 3281 mm L_T, k = 0·12). Age at maturity was calculated to be 10·4 and 13·2 years for males and females, respectively, and these are the oldest estimated for this species. The samples of S. lewini were heavily biased towards females, and the model of best fit for males and females was the three‐parameter Gompertz (L_∞ = 2598 mm L_T, k = 0·15) and the two‐parameter Gompertz (L_∞ = 2896 mm L_T, k= 0·16). Age at maturity was calculated to be 8·9 and 13·2 years for males and females, respectively. Although numerous age and growth studies have previously been undertaken on S. lewini, few studies have been able to obtain adequate samples from all components of the population because adult females, adult males and juveniles often reside in different areas. For the first time, sex bias in this study was towards sexually mature females, which are commonly lacking in previous biological studies on S. lewini. Additionally, some of the oldest aged specimens and highest age at maturity for both species were observed in this study. Both species exhibit slow rates of growth and late age at maturity, highlighting the need for a re‐assessment of the relative resilience of these two globally threatened sharks at current high levels of fishing mortality throughout the eastern Indian Ocean.     

Age and growth of the sandbar shark, Carcharhinus plumbeus, in Hawaiian waters through vertebral analysis

Age and growth estimates were determined for the sandbar shark, Carcharhinus plumbeus, from Oahu, Hawaii in the central Pacific Ocean. Age estimates were obtained through vertebral centra analysis of 187 sharks. We verified our age estimates through marginal increment analysis of centra and oxytetracycline marking methods of at liberty sandbar sharks. Sizes of sampled sharks ranged from 46 to 147 cm pre-caudal length. Four growth models were fitted to length-at-age data; two forms of the von Bertalanffy growth model, the Gompertz growth model, and a logistic growth model. Males and females exhibited statistically significant differences in growth, indicating that females grow slower and attain larger sizes than males. Growth parameter estimates revealed slower growth rates than previously estimated (based on captive specimens) for Hawaiian sandbar sharks. The von Bertalanffy growth model using empirical length-at-birth provided the best biological and statistical fit to the data. This model gave parameter estimates of L _∞ = 138.5 cm PCL and k = 0.12 year⁻¹ for males and L _∞ = 152.8 cm PCL, k = 0.10 year⁻¹ for females. Male and female sandbar sharks mature at approximately 8 and 10 years of age, respectively.     

Age estimates derived from hard parts of swordfish Xiphias gladius from the north-western Mediterranean Sea

Accurate age estimates for fish are critical for properly understanding stock dynamics and health; this is particularly true for larger billfishes. Here we determined the most accurate aging estimation methods for swordfish (Xiphias gladius). We compared age estimates obtained from fin-ray sections, otolith sections, whole otoliths, and vertebrae collected from 87 swordfish off the east coast of Corsica. Age estimates from otolith sections were most consistently estimated across different readers (lowest average percentage error), followed by fin-ray sections, third vertebrae, and whole otoliths. When the age estimates from the otolith sections were compared with the other three age sclerochronological methods, we found the average percentage error to be lowest between the otolith section and fin-ray methods. However, age estimates from fin rays proved most useful for estimating swordfish younger than 6 years, as the fin ray-based age diverged from that of the otolith sections as the swordfish aged. Combining fin ray and otolith section techniques, we estimated the growth parameters of 1–12-year-old females (L_∞ = 259.412, k = 0.113, t₀ = −2.499) and 1–7-year-old males (L_∞ = 175.543, k = 0.202, t₀ = −2.239). We found that females grew significantly faster than males after 3 years and remained larger thereafter. Our calculated growth rates for this region of the north-western Mediterranean Sea were lower than those of the Atlantic, Pacific, and eastern Mediterranean Sea swordfish populations, and similar to growth rates recorded for the western Mediterranean Sea populations. Our study provides critical knowledge on biological-related parameters to serve as a guide for preserving the swordfish population in the Mediterranean Sea.     

Two new North Pacific skates (Rajidae) and a revised key toBathyraja in the area

Two new species of the skates,Bathyraja hubbsi andB. pseudoisotrachys are described from the North Pacific. Among the North PacificBathyraja, B. hubbsi most closely resemblesB. violacea Suvorov in possessing a disc without thorns, a median tail thorns irregularly spaced, and minute fine prickles covering the entire dorsal surface. The two species are distinguished from each other by their dorsal color pattern, proportional measurement of tail in relation to total length, clasper components, and number of precaudal vertebrae.Bathyraja pseudoisotrachys has long been confused withB. isotrachys (Günther) by many Japanese authors, but is distinguished from other North PacificBathyraja by dorsal squamation and unique clasper components such as two clefts, terminal bridge and ridge.Bathyraja kincaidii Garman is synonymized with the valid speciesB. interrupta Gill et Townsend.Bathyraja abyssicola Gilbert andB. trachura Gilbert are redescribed in detail. Provisionally, 21 species of the genusBathyraja are recognized in the present study from this region, and a revised key is given to the North Pacific species of the genus.     

Identification of multiple nursery habitats of skates in the eastern Bering Sea

The use of more than a single nursery habitat type is examined for oviparous elasmobranchs using data summarized from studies conducted on the Alaska skate Bathyraja parmifera and the Aleutian skate Bathyraja aleutica in the eastern Bering Sea. The eastern Bering Sea skate species use two discrete areas as nurseries, one for egg deposition and a second for newly emergent juveniles. Egg deposition sites were located along the outer shelf and upper slope near canyons in the eastern Bering Sea. Newly emergent juveniles were found along the outer and middle shelf for B. parmifera and deep‐slope for B. aleutica, suggesting that habitat used by newly emergent juvenile skates is distinct from habitat used for egg deposition and embryo development. In reviewing many studies on oviparous elasmobranchs, similar patterns emerge of habitat use during their early life history. To distinguish these distinct habitats, appropriate terminology is proposed. Egg case nursery is suggested for areas of egg deposition and juvenile nursery is suggested for areas where juveniles aggregate after emergence. Criteria to describe each habitat type are outlined.     

Periodicity of the growth-band formation in vertebrae of juvenile scalloped hammerhead shark Sphyrna lewini from the Mexican Pacific Ocean

The age of 296 juvenile scalloped hammerhead sharks Sphyrna lewini caught by several fisheries in the Mexican Pacific Ocean from March 2007 to September 2017 were estimated from growth band counts in thin-sectioned vertebrae. Marginal-increment analysis (MIA) and centrum-edge analysis (CEA) were used to verify the periodicity of formation of the growth bands, whereas elemental profiles obtained from LA-ICP-MS transect scans in vertebrae of 15 juveniles were used as an alternative approach to verify the age of the species for the first time. Age estimates ranged from 0 to 10+ years (42–158.7 cm total length; L_T). The index of average percentage error (I_APE 3.6%), CV (5.2%), bias plots and Bowker's tests of symmetry showed precise and low-biased age estimation. Both MIA and CEA indicated that in the vertebrae of juveniles of S. lewini a single translucent growth band was formed during winter (November–March) and an opaque band during summer (July–September), a period of faster growth, apparently correlated with a higher sea surface temperature. Peaks in vertebral P and Mn content spatially corresponded with the annual banding pattern in most of the samples, displaying 1.19 and 0.88 peaks per opaque band, respectively, which closely matched the annual deposition rate observed in this study. Although the periodicity of growth band formation needs to be verified for all sizes and ages representing the population of the species in the region, this demonstration of the annual formation of the growth bands in the vertebrae of juveniles should lead to a re-estimation of the growth parameters and productivity of the population to ensure that it is harvested at sustainable levels.     

Age and growth of the bonnethead shark, Sphyrna tiburo, from northwest Florida, with comments on clinal variation

Age and growth rates of the bonnethead shark, Sphyrna tiburo, from northwest Florida were estimated from vertebrae collected between October 1992 and October 1995. The von Bertalanffy growth equation was fit to male and female vertebral age data. Initial growth was rapid (≈ 200 mm TL) for both sexes from age 0–1. At age 2 growth slowed for males but continued for females. Similar to many species of sharks, females grew slower than males (K = 0.28 and K = 0.69, respectively) but attained a larger maximum size (L_∞=1226 and L_∞=897). Maximum age was estimated in males and females to be 8+ and 12+ years, respectively. Growth of young-of-year sharks was 21 to 30 mm TL per month determined by three different methods. A comparison of age and growth estimates from populations at more southerly latitudes suggest that clinal variation in total length may be evident among bonnethead sharks in the Gulf of Mexico with females reaching larger sizes in northern areas as compared to south Florida. This revised version was published online in July 2006 with corrections to the Cover Date.     

Age structure, growth and survival rates of the commercial fish Prochilodus nigricans (bocachico) in North-eastern Ecuador

The bocachico, Prochilodus nigricans, is a commercially important fish distributed throughout the central and western Amazon. Age and growth of this species in eastern Ecuador were determined by otolith and scale increment analyses. For otolith analyses, we used thin sections of the astericus, and clear visualization of annuli required the use transmitted polarized light. Accuracy and precision of age estimation were compared to select the best ageing structure. Precision indices showed that otoliths are more reliable than scales to determine the age of bocachicos. Based on marginal increments analysis, we found that annulus formation in both structures occurs once a year between August and December. Seasonal changes in growth were associated with hydrological cycle of the river. The Ecuadorian Prochilodus at the juvenile–adult stage grew faster (i.e., K = 0.29 for ages 2 and older) than conspecific populations from Bolivia and Brazil (K = 0.5). In addition, annual mortality rate (A = 0. 56) was lower than reported for Prochilodus populations elsewhere in the Amazon. We conclude that this population is presently not overexploited, but conservation and management schemes for this population will need to consider that it is an international, trans-boundary migrant.     

Age and growth of the round stingray Urobatis halleri at Seal Beach, California

The age and growth of the round stingray Urobatis halleri was determined using vertebral sections from animals collected at Seal Beach, California from 2002 to 2005. Annual periodicity was validated from U. halleri injected with oxytetracycline and maintained in captivity over a 2 year period ( n = 7). The coefficients estimated by the von Bertalanffy growth model were the disc width asymptote ( W _D∞) (286 mm for males and 224 mm for females) and K (0·09 year⁻¹ for males and 0·15 year⁻¹ for females). The age structure of the population consisted of mostly older, mature males and females. Age at maturity was estimated at 3·80 years for females and 3·75 years for males, and the maximum assessed age was 14 years old. Males were more numerous than females throughout the year; however, from May to September, females outnumbered males. The U. halleri age and growth coefficients were comparable to other species in the family Urolophidae. Based on the seasonality and age structure of this population, Seal Beach offers warm-water refuge for U. halleri of reproductive maturity, and the U. halleri at Seal Beach may garner some behavioural thermoregulation benefit.     

Age and growth of black seabream Acanthopagrus schlegelii (Sparidae) in Hong Kong and adjacent waters of the northern South China Sea

Age and growth of the black seabream Acanthopagrus schlegelii (family Sparidae) from the northern South China Sea (NSCS) were studied by reading growth rings in sectioned sagittal otoliths. Ring formation frequency was determined to be annual by using marginal increment analysis. The von Bertalanffy growth function parameters were estimated as: L_∞ = 43.7 cm L_S; K =0.22 year; t₀ = ?1.59 years. Functional males are significantly younger than functional females, with sexually transitional individuals between the modal ages of males and females supporting protandry in this species. Males become sexually mature within 1 year and 50% age at sex change is at 2 years. The maximum age recorded for both males and females sampled was 9 years which is lower than for conspecifics elsewhere and may reflect high fishing pressure in the study area when compared with conspecifics in other areas or could reflect latitudinal effects. Otolith mass was significantly and positively related to age, providing a cheap and quick alternative method for approximating age. Acanthopagrus schlegelii is a relatively fast‐growing and rapidly maturing species attaining a similar asymptotic length to conspecifics. A need for fishery management is indicated to protect both young juveniles and older adults, especially females, to increase reproductive output and safeguard fishery production.     

Growth and derived life-history characteristics of the Brazilian electric ray Narcine brasiliensis

The majority of batoids are listed as Threatened (20.4%) or Data Deficient (41%) by the IUCN Red List. A key challenge to assessing Data-Deficient species is obtaining estimates of key life-history characteristics. Here, a Bayesian approach was used to estimate derived life-history characteristics from a growth model applied to the Data-Deficient Brazilian electric ray Narcine brasiliensis. The age of 170 specimens (107 females, 63 males) was estimated from vertebral centra, and total length, disc width, total weight and birth size were used in a joint estimation of sex-specific length-weight models and two-dimensional von Bertalanffy growth models. Estimates of age at length zero, age at maturity, longevity and mortality at age were derived simultaneously. The Bayesian joint modelling approach was robust to small sample sizes by adding a likelihood to constrain L₀ and sharing parameters, such as Brody growth coefficient between length measurements. The median growth parameter estimates were a shared L₀ = 38.8 mm, female L_∞ = 515 mm, 𝑘 = 0.125 and male L_∞ = 387 mm, 𝑘 = 0.194. Age at maturity was estimated to be 7.40–7.49 years for females and 4.45–4.47 years for males, whereas longevity was 22.5–22.6 years for females and 14.2 years for males depending on length measurement. Age-1 natural mortality was estimated to be 0.199–0.207 for females and 0.211–0.213 for males. The derived life-history characteristics indicate N. brasiliensis is earlier maturing, but slower growing relative to other Torpediniformes. These characteristics along with the species’ endemism to southern Brazil and high by-catch rates indicate that one of the IUCN Red List threatened categories may be more appropriate for the currently Data-Deficient status. The Bayesian approach used for N. brasiliensis can prove useful for utilizing limited age-growth data in other Data-Deficient batoid species to inform necessary life characteristics for conservation and management.