Spine Sections Research Articles

Multiple spine boutons are formed after long-lasting LTP in the awake rat

The formation of multiple spine boutons (MSBs) has been associated with cognitive abilities including hippocampal-dependent associative learning and memory. Data obtained from cultured hippocampal slices suggest that the long-term maintenance of synaptic plasticity requires the formation of new synaptic contacts on pre-existing synapses. This postulate however, has never been tested in the awake, freely moving animals. In the current study, we induced long-term potentiation (LTP) in the dentate gyrus (DG) of awake adult rats and performed 3-D reconstructions of electron micrographs from thin sections of both axonal boutons and dendritic spines, 24 h post-induction. The specificity of the observed changes was demonstrated by comparison with animals in which long-term depression (LTD) had been induced, or with animals in which LTP was blocked by an N-methyl-D-aspartate (NMDA) antagonist. Our data demonstrate that whilst the number of boutons remains unchanged, there is a marked increase in the number of synapses per bouton 24 h after the induction of LTP. Further, we demonstrate that this increase is specific to mushroom spines and not attributable to their division. The present investigation thus fills the gap existing between behavioural and in vitro studies on the role of MSB formation in synaptic plasticity and cognitive abilities.

English

The study aims to identify the age and growth parameters of bullet tuna ( Auxis roche i) in Turkish waters. The fish were caught from the Turkish Mediterranean coasts between December 2008 and December 2009. A total of 186 dorsal fin spines obtained from the specimens were analyzed for ageing and growth studies. The fork length of the aged individuals ranged from 34 to 48 cm for males and from 35 to 46.5 cm for the females. Fish ages ranged 1 to 5 years old and the mean lengths by age were calculated for both sexes. Growth parameter estimates were calculated from 150 cut spine sections which provided readable growth annuli by sex. The growth parameters based on standard von bertalanffy growth function are the following: for males, L∞ (asymptotic length) is equal to 60.417 cm; k (growth coefficient) is equal to 0.159; t 0 (age at zero length) is equal to − 4.311; for females, L∞ is equal to 49.238 cm; k is equal to 0.312; t 0 is equal to −3.011; for both sexes, L∞ is equal to 57.388 cm; k is equal to 0.181and t 0 is equal to −4.155, respectively. The length and weight relationship was calculated with W equal to 0.0542 L 2.68 . Key words : Bullet tuna, Auxis rochei, age determination, growth, the Mediterranean sea.

Validation of age estimates obtained from juvenile pallid sturgeon Scaphirhynchus albus pectoral fin spines

Pallid sturgeon Scaphirhynchus albus are a federally-listed endangered species, yet little is known about their population dynamics, including age and growth. Age validation is needed before the accuracy of age estimates and ensuing analyses is known. Therefore, we evaluated the accuracy and precision of age estimates obtained from 36 pallid sturgeon recaptured from the lower Missouri River. Accuracy of age estimates varied among three readers from 28 to 41%. Most deviations from the actual age were within 1 year, and most fin spine sections were overaged due to an apparent false annulus near the focus of the section. Between-reader agreement varied by reader combination but was generally around 30%. Our findings suggest that careful attention be paid to age and growth information obtained from hatchery-reared pallid sturgeon fin spines and further methods of accurately estimating age of pallid sturgeon need to be developed.

Comparison of age estimates from otoliths, vertebrae, and pectoral spines in African sharptooth catfish,Clarias gariepinus(Burchell)

Otoliths, vertebrae, and pectoral fin spine sections were compared to ascertain the best ageing structure in Clarias gariepinus. Standard procedures were followed to prepare and study the age structures. All ageing structures showed alternating opaque and translucent bands that were interpreted as annuli. Age estimates were evaluated for comparison between readers and among structures. Among all structures otoliths showed highest (95.6%) agreement between readers, followed by vertebrae (91.2%) and pectoral spine sections (79.7%). Due to the highest values of percent agreement and lowest average percent error and coefficient of variation values between two readers, otoliths were considered to be the most suitable structure for ageing C. gariepinus. When otoliths' ages were compared with other bony structures, viz. vertebrae and pectoral spine sections, the highest percent agreement and lowest average percent error and coefficient of variation values were found between otoliths and vertebrae age estimates (90.7%). Mean age estimates from otoliths were comparable (P > 0.05) to the values obtained from vertebrae but significantly (P < 0.05) different to those from pectoral fin spine sections.

Trace elements in the otoliths and dorsal spines of albacore tuna (Thunnus alalunga, Bonnaterre, 1788): An assessment of the effectiveness of cleaning procedures at removing postmortem contamination

Trace element analysis or “elemental fingerprinting” is widely used in stock structure analyses. Postmortem contamination of bony structures can confound the results of microconstituent studies or introduce an additional source of noise to the data, thus reducing the ability of the technique to detect real variation in trace element concentrations. Despite the potential for postmortem contamination during sample preparation, the effectiveness of the procedures used to remove potential contaminants from sectioned otoliths and other calcareous structures prior to laser ablation inductively coupled plasma mass spectrometry (LA ICP-MS) has not previously been addressed. Otoliths and dorsal spine sections of albacore tuna (Thunnus alalunga) collected from the North East Atlantic Ocean and the Mediterranean Sea were deliberately contaminated prior to analysis of trace element composition using LA ICP-MS. The effectiveness of three cleaning treatments (rinsing in ultrapure water, 30% hydrogen peroxide and ultrapure 5% nitric acid) at removing this postmortem contamination were compared. Magnesium and strontium were relatively robust to postmortem effects when exposed to contamination at concentrations of 50ppm and 200ppm respectively. Soaking in a solution containing Mn, Cs and Ba (50ppm) caused a marked increase in the detected concentration of each element in both structures. Translucent bands in both structures were more susceptible to contamination. Rinsing in ultrapure water or hydrogen peroxide was not effective at removing Mn, Cs and Ba contamination from either calcareous structure. Washing the otoliths and spines in nitric acid successfully removed postmortem contaminants.The removal of otoliths from tuna damages the appearance of the fish and has an adverse effect on market value. However spines are easily removed, do not affect the appearance or value of the fish and are the most commonly used structure for age determination. A weak but significant correlation was observed between Ba in opaque zones in otoliths and dorsal spines. All other spine to otolith correlations were not significant. The results do not provide support for the use of spines as an alternative to otoliths in trace elemental analyses.

Distribution and Growth of Grey Triggerfish, Balistes capriscus (Family: Balistidae), in Western Gulf of Guinea

The grey triggerfish, Balistes capriscus, resource had declined for nearly two decades in West African waters; its distribution and growth remain to be reported after late 1980s. In order to fill this gap, specimens were collected during small pelagic fish stock assessment surveys in 2005 in coastal waters of Benin, Togo, Ghana and La Cote d’Ivoire (Western Gulf of Guinea) from 17 out of 165 swept-area hauls in depths range of 23–60 m. The modal size classes were 27.0–31.9 cm and 32.0–36.9 cm. The age classes were determined by interpreting growth rings on sections of first dorsal spines. Estimates of theoretical growth in length were obtained by fitting the observed length-at-age data to the standard form of von Bertalanffy growth equation. The estimated L∞ for B. capriscus was 45.1 ± 1.4 cm and the growth rate, K, was 0.21 yr-1. The phi prime (O’) growth performance obtained was 2.63, which is comparable to that obtained in the 1980s on the same fish species in waters of Senegal, La Cote d’Ivoire and Ghana. The results suggest that the growth and distribution of grey triggerfish in the Western Gulf of Guinea had not changed, in spite of the apparent disappearance of the fish species in many areas of the West African coastal waters for nearly two decades.

Accuracy and Precision of Estimates of Back‐Calculated Channel Catfish Lengths and Growth Increments Using Pectoral Spines and Otoliths

AbstractBack‐calculation of lengths at previous ages using measurements of growth increments on the bony structures of fish is a common practice, yet studies validating this procedure are few. Our objective was to determine the accuracy and precision of back‐calculated lengths and the last growth increment for channel catfish Ictalurus punctatus using pectoral spines and otoliths. In recent studies, the last growth increment has been related to the length of the fish at the start of the growing season to determine size‐specific growth. Growth increments on basal sections of pectoral spines were measured along three radii—posterior (SP), anterior (SA), and lateral (SL)—and otoliths were measured along the ventral radius by three independent readers. Back‐calculated lengths derived from eight models (biological intercept, body‐proportional hypothesis [BPH] linear, BPH nonlinear, Dahl–Lee, Fraser–Lee, Morita–Matsuishi, scale‐proportional hypothesis [SPH] linear, and SPH nonlinear) for each bony structure radius were compared with the actual growth histories of captive channel catfish to determine the best model and radius (for pectoral spines) for the two bony structures. The SPH linear model for SL provided the most accurate data for pectoral spines and was also appropriate for otoliths. Back‐calculated lengths and last growth increments were considerably more accurate and precise for SL than for otoliths. The SPH linear model provided an initial length–last growth increment relationship that was similar to the observed relationship for SL but not for otoliths. We also estimated last growth increments and the initial length–last growth increment relationship from the traditionally used Dahl–Lee model for SP and found that these estimates were similar to those derived from the SPH linear model for SL. We recommend using the SPH linear model for SL to estimate length‐at‐age and growth increment data. However, the Dahl–Lee model for SP also provides reasonable estimates of the last growth increment.

Lake Sturgeon Age Validation using Bomb Radiocarbon and Known‐Age Fish

AbstractPectoral fin spines have been the accepted structure for estimating the age of various sturgeon species for nearly 100 years, though other structures have also been used (otoliths, pectoral girdle, scutes, and caudal fulcra). Accuracy of age estimates using any of these structures has not been validated, so we report the first use of bomb radiocarbon (14C) assays to assess the validity of ages estimated using growth increments on pectoral fin spine and otolith frontal cross sections from lake sturgeon Acipenser fulvescens; we also assessed age estimates from pectoral fin spines of known‐age lake sturgeon. Growth increments on pectoral fin spine cross sections underestimated true age of fish older than 14 years and error increased with age, whereas otoliths accurately estimated true age up to at least 52 years. Increment formation on pectoral fin spine and otolith cross sections from juvenile lake sturgeon (ages 2‐11) was similar, although pectoral spines were clearer and easier to interpret. A power function (true age = [estimated age]1.054796, where estimated age was determined from pectoral spines; r2 = 0.98) provides a means for correcting existing age estimates obtained from lake sturgeon pectoral fin spines.

Lake Erie Yellow Perch Age Estimation Based on Three Structures: Precision, Processing Times, and Management Implications

AbstractYellow perch Perca flavescens support economically important recreational and commercial fisheries in Lake Erie and are intensively managed. Age estimation represents an integral component in the management of Lake Erie yellow perch stocks, as age‐structured population models are used to set safe harvest levels on an annual basis. We compared the precision associated with yellow perch (N = 251) age estimates from scales, sagittal otoliths, and anal spine sections and evaluated the time required to process and estimate age from each structure. Three readers of varying experience estimated ages. The precision (mean coefficient of variation) of estimates among readers was 1% for sagittal otoliths, 5–6% for anal spines, and 11–13% for scales. Agreement rates among readers were 94–95% for otoliths, 71–76% for anal spines, and 45–50% for scales. Systematic age estimation differences were evident among scale and anal spine readers; less‐experienced readers tended to underestimate ages of yellow perch older than age 4 relative to estimates made by an experienced reader. Mean scale age tended to underestimate ages of age‐6 and older fish relative to otolith ages estimated by an experienced reader. Total annual mortality estimates based on scale ages were 20% higher than those based on otolith ages; mortality estimates based on anal spine ages were 4% higher than those based on otolith ages. Otoliths required more removal and preparation time than scales and anal spines, but age estimation time was substantially lower for otoliths than for the other two structures. We suggest the use of otoliths or anal spines for age estimation in yellow perch (regardless of length) from Lake Erie and other systems where precise age estimates are necessary, because age estimation errors resulting from the use of scales could generate incorrect management decisions.

Using traditional age and growth techniques in endangered species management: eastern freshwater cod, Maccullochella ikei

Age and growth estimates can be difficult to obtain for endangered fishes owing to their relative low abundance and the ethics associated with sampling threatened populations. The eastern freshwater cod, Maccullochella ikei Rowland 1985, is an endangered freshwater fish endemic to the Clarence and Richmond Rivers of New South Wales, Australia. Bony parts were gathered from archival collections and hatcheries, as well as opportunistically from the wild, to determine age and growth. Examination of opercular bones and dorsal spine sections revealed no consistent annuli. Sectioned otoliths exhibited consistent bipartite rings throughout the structures and 106 otoliths were used to estimate the age of cod from 0+ to 15+ years. Edge increment analysis and known-age cod were used to validate the age estimates. The von Bertalanffy growth equation for M. ikei is Lt = 704.9 (1–exp (–0.20 (t + 0.14))). A length–weight relationship of W = 2.80 × 10–6 × L3.2467 was established from 372 cod collected using non-destructive techniques. Significant differences were found in the relative condition of cod in summer (Kn = 0.999) and winter (Kn = 1.026). The information presented in this paper will assist in the conservation of M. ikei and will provide a guide for future age and growth studies of threatened species.

Early‐onset degeneration of the intervertebral disc and vertebral end plate in mice deficient in type IX collagen

Type IX collagen is an important component of the intervertebral disc extracellular matrix. Mutations in type IX collagen are associated with premature disc degeneration in mice and a predisposition to disc disorders in humans. The aim of this study was to assess the prevalence and timeline of intervertebral disc degeneration in mice homozygous for an inactivated Col9a1 gene. Intact spine segments were harvested from wild-type (WT) and type IX collagen-knockout (Col9a1(-/-)) mice at 3, 6, and 12 months of age. Sagittal spine sections were evaluated for evidence of histologic changes, by 2 blinded graders, using a semiquantitative grading method. There was evidence of more degeneration of the disc and end plate in the spines of Col9a1(-/-) mice compared with those of WT controls, at most time points. These findings were significant for the disc region at 3 and 6 months (P<0.01) and at 12 months (P<0.10) and for the end plate region only at 6 months (P<0.10). Degenerative changes in the disc consisted of cellular changes and mucous degeneration. Degeneration in the end plates was associated with more cell proliferation, cartilage disorganization, and new bone formation. A deletion mutation for type IX collagen is associated with connective tissue changes characteristic of musculoskeletal degeneration in bony and cartilaginous tissue regions. Some of the observed changes were similar to cartilage changes in osteoarthritis, while others were more similar to disc degenerative changes in humans. The finding of premature onset of intervertebral disc degeneration in this mouse model may be useful in studies of the pathology and treatment of human disc degeneration.

Age estimation of the Atlantic bonito in the eastern Mediterranean Sea using dorsal spines and validation of the method

SUMMARY: Growth parameters were studied in 397 specimens of the Atlantic bonito caught in the eastern Mediterranean Sea (Aegean and Ionian Seas) ranging from 7.2 to 72.5 cm in fork length and from 2 to 5400 g in total weight. The study of the growth bands in spine sections showed that one translucent ring is formed annually during the cold season. The growth parameters estimated (L ∞ = 82.99 cm, K = 0.24, t 0 = -0.77) express the growth of the species more realistically than previous studies in the Mediterranean Sea and the Atlantic Ocean.

The relative contribution of intervertebral disc to the curvatures of the vertebral column

Habitual bipedality (BI), a human hallmark characteristic, is a defining specialization central to the evolutionary development of all our other uniquely human characters - large brain, tool making, hunting, and language. Characters alleged to be exclusively associated to BI include disposition and orientation of foramen magnum, lumbar curvature (CU), and a non-opposable adducted great toe, which have been used to argue for fossils to be bipeds and thus human ancestors. Regarding spinal CU, it is uncertain whether CU and thus BI can be inferred solely from fossilized remains. The non-fossilizing soft-tissue, the inter-vertebral discs (IVD), may be largely responsible for the CU. To determine the validity of reconstructing CU based solely on bony remains this study examines the contribution of IVD and vertebral body joint (VBJ) surface orientation to the thoracic and lumbar CUs of the spine in cadavers and living humans. MR sagittal spine sections of seven healthy adult individuals, and seven cadaveric vertebral columns were measured for cervical, thoracic and lumbar CU using Cobb’s angle. Contribution of each IVD and VBJ surface orientation to CU was measured directly from the MR images and from tracings of the vertebral columns of cadavers. Results show that in the thoracic region VBJ surface orientation contributed 95% of the CU and IVD only 5%. The IVD between the last lumbar and 1st sacral vertebrae, however, contributed as much as 14% towards lumbar CU. Our preliminary results indicate lumbar CU measures based solely on fossilized hard tissue are accurate except in the case of the lumbosacral joint.

Year‐Class Strength and Recovery of Endangered Shortnose Sturgeon in the Hudson River, New York

AbstractShortnose sturgeon Acipenser brevirostrum, a U.S. endangered species, has experienced a fourfold increase in abundance in the Hudson River in the past three decades. The age structure and trends in year‐class strength of yearlings were investigated to evaluate the underlying pattern of annual recruitment that accompanied population recovery. Annuli in pectoral spine sections were used to estimate ages of specimens captured with gill nets bimonthly from November 2003 to November 2004. Age estimates (range = 5–30 years) were generated for 554 shortnose sturgeon ranging from 49 to 105 cm total length. Hindcast year‐class strengths corrected for gear selectivity and cumulative mortality indicated high recruitments (31,000–52,000 yearlings) during 1986–1992. This interval was preceded and succeeded by approximately 5‐year periods of lower recruitment (6,000–17,500 yearlings), suggesting 10‐fold recruitment variability over the 20‐year period. The pattern and relative magnitude of hindcast recruitment patterns were corroborated by shortnose sturgeon catch‐per‐unit‐effort trends in an independent beam trawl survey. An analysis of hindcast year‐class abundance and coincident environmental conditions indicated that flow volume and water temperature in the fall months preceding spawning were significantly correlated with subsequent year‐class strength. Our results suggest that shortnose sturgeon of the Hudson River have experienced several strong year‐classes concomitant with the observed population recovery during the 1980s and 1990s. The data indicate that population growth slowed during the late 1990s, as evidenced by a nearly constant recruitment pattern at depressed levels relative to the 1986–1992 year‐classes.

Comparison of deterministic growth models fitted to length-at-age data of the piked spurdog (Squalus megalops) in south-eastern Australia

Age and growth estimates of Squalus megalops were derived from the first dorsal fin spine of 452 sharks, ranging from 274 to 622 mm total length. Age bias plots and indices of precision indicated that the ageing method was precise and unbiased. Edge analysis of the enameled surface of whole spines and similarities in the banding pattern deposited in the enameled surface of spines and in spine sections supported the hypothesis of annual band formation. Multiple versions of two growth models were fitted to length-at-age data, from which a two-phase von Bertalanffy model produced the best fit. For males, the change in growth rate corresponded with size-at-maturity, whereas for females, the change was slightly before size-at-maturity. Regardless of the growth model used, growth rate of females (0.034 to 0.098 years–1) was very low, making S. megalops highly susceptible to overexploitation by fisheries.

Special Tests for Orthopedic Examination, ed 3

Konin JG, Wiksten DL, Isear JA Jr, Brader H. Thorofare, NJ 08086, Slack Inc, 2006, spiralbound, 400 pp, illus, ISBN: 1-55642-741-7, $38.95. This text, authored by both physical therapists and athletic trainers, is intended to provide a condensed guide for the examination of people with orthopedic injuries. In my opinion, this goal has been surpassed. Designed as a “pocket-style” manual, the 400 pages in this third edition push the definition of “pocket guide,” but make up for the additional size with an abundance of information. Designed for physical therapists, athletic trainers, physicians, physician assistants, and occupational therapists, this text covers a plenitude of orthopedic tests. Like other texts of this kind, the special tests in this book are organized into 12 sections according to the major spinal segments and peripheral joints. A total of 155 special tests are offered, ranging from as few as 3 for the temporomandibular joint and thoracic spine sections to as many as 34 for the shoulder. In addition to the joint-by-joint arrangement, an alphabetical index at the end of the text allows …

Difference in Channel Catfish Growth among Mississippi Stream Basins

AbstractWe investigated basin‐scale factors that were likely to influence the growth of channel catfish Ictalurus punctatus in Mississippi floodplain rivers. Channel catfish were collected from nine streams during 2001–2002. All fish were measured (total length; mm) and aged from pectoral spine sections. Linear growth models were fitted to mean back‐calculated length‐at‐age data for channel catfish from each stream and were compared among streams. Channel catfish growth rate differed among streams. Multiple linear regression was used to correlate growth rate to basin‐scale environmental variables. The growth rate for channel catfish was related positively to soil fertility and negatively to altitude and percentage of the watershed comprising bottomland hardwood forest. Basin‐scale determination of environmental features related to channel catfish growth can assist managers and fisheries administrators with establishment of realistic expectations for riverine channel catfish fisheries at a scale that is administratively feasible and functionally defensible.

A new species of Xyloplax (Echinodermata: Asteroidea: Concentricycloidea) from the northeast Pacific: comparative morphology and a reassessment of phylogeny

Abstract. Xyloplax janetae n. sp. is described from the northeast Pacific Ocean. This is the third species recognized for the monogeneric Concentricycloidea. Skeletal structures are elaborated by scanning electron microscopy and compared with those of Xyloplax medusiformis from New Zealand and Xyloplax turnerae from the Bahamas. Critical‐point‐dried specimens show fibrous connective tissue emerging from openings on the abactinal surface, on the abactinal spine bases, and at broken cross sections of the adambulacral spines. Knob‐like structures emerging through the stereom openings of the abactinal spine base are also observed. Tube feet have round, swollen knobs and show few striations relative to other asteroids. Cosmopolitan bathyal–abyssal echinoderm species tend to exhibit few morphological differences over broad geographic ranges; this generalization is true of Xyloplax. The Concentricycloidea is proposed as an infraclass within the Asteroidea, as the sister branch to the Neoasteroidea (the crown‐group asteroids) within the subclass Ambuloasteroidea. The hypothesis presented is compatible with recent phylogenetic data supporting affinities between Xyloplax and the Asteroidea. Characters plesiomorphic in basal neoasteroids are consistent with a sister‐group relationship to concentricycloids. Actinal plate presence, an important synapomorphy for the Neoasteroidea, is absent from concentricycloids. The substantial morphological departure of Xyloplax is considered to be associated with the post‐Paleozoic diversification of crown‐group asteroids rather than from modification of an established and conservative morphology.

Accuracy and precision of age determination techniques for Mississippi River bighead carp Hypophthalmichthys nobilis (RICHARDSON 1845) using pectoral spines and scales

Age determination techniques for bighead carp Hypophthalmichthys nobilis from the Mississippi River (MR) were investigated. Sagittal otoliths, cleithrum bones, scales, and pectoral spines were obtained from bighead carp collected from the middle Mississippi River (MMR) and from Pool 26 of the MR. Known-age bighead carp (Age 1, N = 3 and age 2, N = 5) pond-reared in a fish farm were used to aid in the interpretation and validation of age assessments. Sagittae and cleithra were cloudy and annuli were difficult to identify both in whole view and sectioned; they were not evaluated further. All pectoral spine sections (N = 98) and scales (N = 57) from known-age and unknown-age specimens were read by three readers. Readers were provided with the date of capture and were not informed of the presence of known-age bighead carp. Percent agreement among age estimates from unknown-age bighead carp was 19 % for scales and 23 % for spine sections. There was approximately 60 % agreement within one year for both structures. Agreement for age 1 bighead carp using scales was 100 %, and 20 % for age 2 specimens. Using spine sections, agreement was 67% for both age 1 and age 2 known-age bighead carp. Mean percent accuracy interpreting the age of known-age bighead carp was 69 % for spine sections and 78 % for scales. Accuracy of scale readings was 100 % for age 1 and 60% for age 2. A multiple regression analysis of age estimates by the readers showed no significant difference (p >0.05) between the aging structures and the dependent variable, estimated age, but a significant aging structure by mean estimated age interaction was found. Scales yielded lower age estimates than spine sections for older bighead carp, while spine sections yielded lower age estimates for younger bighead carp. We suggest using pectoral spine sections to age older bighead carp (2 and older), because they showed more and sharper annuli than scales.

Validity of Otoliths and Pectoral Spines for Estimating Ages of Channel Catfish

Abstract Basal recess and articulating process sections of pectoral spines are often used to estimate the age of channel catfish Ictalurus punctatus. However, identification of annuli in pectoral spine sections can be difficult. We developed and validated a method for estimating the age of channel catfish by using sagittal otoliths. We also validated a new method using pectoral spines in which a single cut is made through the dorsal and anterior processes (hereafter termed cut spines) and annuli are enhanced with side illumination. Age estimates from otoliths and cut spines were compared with age estimates from traditional articulating process sections of pectoral spines for channel catfish of known ages (1–4). Age estimates by the three methods were correct for more than 90% of fish after two experienced readers independently estimated ages and resolved disagreements by mutual examination. Otoliths were more accurate and less variable in estimating age. Otolith age estimates were always within 1 year and...