Total Length Research Articles

Range extension of Blackstripe Lizardfish, Synodus nigrotaeniatus Allen, Erdmann & Peristiwady, 2017 (Actinopterygii, Aulopiformes, Synodontidae), from Jakarta Bay, Indonesia

Three specimens (194.4–203.8 mm standard lengths) of the lizardfish Synodus nigrotaeniatus Allen, Erdmann & Peristiwady, 2017, collected from Jakarta Bay, western Indonesia, represent a significant range extension for the species, which was previously known from only six specimens collected in Lembeh Strait, North Sulawesi, eastern Indonesia. Morphological comparisons with available data from the type specimens and molecular data from the mitochondrial cytochrome oxidase subunit I (COI) gene are presented. The COI sequence data show a 4% genetic difference from the related Synodus sageneus Waite, 1905.

Comparison of external morphological characteristics and movement patterns between Schistosoma japonicum and S. sinensis cercariae

To compare the external morphological characteristics and movement patterns between Schistosoma japonicum and S. sinensis cercariae. S. japonicum and S. sinensis cercariae were heat-fixed, and well-extended cercariae, of 50 each species, were randomly selected for measurement of body length, body width, tail stem length, and tail fork length. The external morphological characteristics of S. japonicum and S. sinensis cercariae were compared. In addition, S. japonicum-infected Oncomelania snails and S. sinensis-infected Tricula snails were observed under a microscope and the movement patterns of S. japonicum and S. sinensis cercariae were compared. The mean body length, body width, tail stem length, and tail fork length were (0.16 ± 0.01), (0.05 ± 0.01), (0.14 ± 0.01) mm and (0.06 ± 0.01) mm for S. japonicum cercariae, and (0.13 ± 0.01), (0.05 ± 0.01), (0.13 ± 0.01) mm and (0.06 ± 0.01) mm for S. sinensis cercariae, respectively, and there were significant differences in terms of cercaria body length (t = 14.583, P < 0.05) and tail stem length (t = 3.861, P < 0.05), while no significant differences were seen in terms of body width (t = 0.896, P > 0.05) or tail fork length (t = -0.454, P > 0.05). Microscopy revealed that the tails of both S. japonicum and S. sinensis cercariae swung from side to side and there was no significant difference in their movement pattern. S. sinensis and S. japonicum cercariae share highly similar external external morphological characteristics and movement patterns.

Changes in Digestive Enzyme Activities during Larval Development of Spotted Seatrout (Cynoscion nebulosus)

The spotted seatrout (Cynoscion nebulosus)—an important commercial species—has a high potential for aquaculture in the Gulf of Mexico. To optimize its feeding during larval rearing, this study aims to evaluate the primary gastric (pepsin), intestinal (leucine aminopeptidase and alkaline phosphatase), and pancreatic (alkaline protease, trypsin, chymotrypsin, amylase, and lipase) enzyme activities from hatching to day 30. A multivariate analysis identified three digestive enzyme development stages during the spotted seatrout larval transformation. The first stage occurred between 1 (mean ± standard error (SE) = 1.73 ± 0.14 millimeter (mm) standard length (SL)) and 3 (2.14 ± 0.07 mm SL) days after hatching (DAH); a period of digestive stability showed the highest activity in amylase and bile salt-dependent lipase. The second stage (from 4 (2.53 ± 0.09 mm SL) to 20 (10.92 ± 0.51 mm SL) DAH) was a period of digestive transition, during which leucine aminopeptidase, chymotrypsin, and alkaline proteases were identified as the predominant enzymes from 4 to 5 DAH. In the third stage—a period of digestive stability—pepsin was the major enzyme that occurred between 25 (16.51 ± 0.81 mm SL) and 30 (25.91 ± 0.82 mm SL) DAH. These results indicate that the spotted seatrout larvae have a digestive system adapted to lipids and carbohydrates at the onset of feeding, with an immediate transition to protein digestion when exogenous feeding begins. Additionally, the digestive system of the spotted seatrout may be considered mature at 25 DAH. Further research is needed to elucidate the mechanisms of digestive tract development in the spotted seatrout larvae.

Improved YOLOv8-Pose Algorithm for Albacore Tuna (Thunnus alalunga) Fork Length Extraction and Weight Estimation

Aiming at the problems of large statistical error and the poor real-time performance of catch weight in the ocean fishing tuna industry, an algorithm based on improved YOLOv8-Pose for albacore tuna (Thunnus alalunga) fork length extraction and weight estimation is proposed, with reference to the human body’s pose estimation algorithm. Firstly, a lightweight module constructed using a heavy parameterization technique is used to replace the backbone network, and secondly, a weighted bidirectional feature pyramid network BIFPN is utilized. Finally, the upper and lower jaw and tail feature points of the albacore tuna (Thunnus alalunga) were extracted using the key point detection algorithm, and the weight of the albacore tuna (Thunnus alalunga) was estimated based on the fitted relationship between fork length and weight. The experimental results show that the improved YOLOv8-Pose algorithm reduces the number of model parameters by 13.63% and the number of floating-point operations by 14.03% compared with the baseline model without decreasing the accuracy of the target detection and key point detection and improves the model inference speed by 374%. At the same time, it reduces the drift of the key point detection, and the error of the comparison with the actual albacore tuna (Thunnus alalunga) body weight is not more than 10%. The improved key point detection algorithm has high detection accuracy and inference speed, which provides accurate yield data for pelagic fishing and is expected to solve the existing statistical problems and improve the accuracy and real-time performance of data in the fishing industry.

Comparative evaluations on the canal-centering ability of novel heat-treated retreatment file system using nano-computed tomography

Abstract Introduction: The main goal of instrumentation during retreatment is to maintain the original curvature of the canal during retrieval of gutta-percha. The present study evaluates the canal-centering ability of two different retreatment file systems. Materials and Methods: Forty extracted single-rooted teeth were decoronated and obturated at the standardized root length of 16 mm. Samples were divided into two groups of each 20 single root teeth and they were instrumented using Solite RS3 Retreatment and ProTaper Retreatment files, respectively. Both pre- and postoperative nano-computed tomography scans were taken, and three-dimensional reconstruction was done for analysis. Sections of both the pre- and postoperative samples were taken at 7 mm, 5 mm, and 3 mm from the apex to calculate the canal-centering ratio. Independent t-test was used for statistical analysis between the two groups. Results: Solite RS3 retreatment files showed a significant difference at the 3 levels (P &lt; 0.000) compared to ProTaper retreatment files. Conclusion: From the above results, we can conclude that Solite RS3 caused minimal canal transportation and produced a relatively centered preparation in comparison to the ProTaper Retreatment system.

Interannual variability in dolphinfish Coryphaena hippurus Linnaeus, 1758 growth in the central-southeastern pacific ocean

The present research provides information on Coryphaena hippurus growth variability in the Central-Southeastern Pacific Ocean. For this purpose, fork length of 48 008 specimens obtained from artisanal fisheries (2006–2022) were used to analyze growth by the multi-model inference approach. According to the results, von Bertalanffy model best described species growth based on Akaike’s Information Criterion. Global growth parameters L∞ = 168.6 cm, k = 1.3, t0 = -0.04, indicated fast growth rates of dolphinfish during the study. This model presented growth and longevity values with greater biological coherence than the logistic and Gompertz models. Growth estimates between cohorts indicated that C. hippurus has interannual and decadal variations associated with the El Niño Southern Oscillation (ENSO) and decadal variation. The information in this study is essential for better understanding C. hippurus growth and serves as a basis for future actions on its management and conservation.

Codon Usage Characteristics and Evolutionary Analysis of Mitochondrial Genome of Winter Squash (Cucurbita maxima Duch.)

Mitochondrial genomes are essential components of eukaryotic cells, understanding their structural characteristics and codon usage bias is critical. Winter squash (Cucurbita maxima Duch ex Poiret) is an economically important cucurbit crop. To clarify its structural characteristics and codon usage bias of mitochondrial genome, as well as the evolutionary characteristics in the Cucurbitaceae family, whole genome sequencing analysis of C. maxima mitochondrial genome was carried out. The results revealed that the total length of the C. maxima mitochondrial genome was 640,814 bp, containing 9,162,318,300 bp of bases. There were 68 annotated genes identified. The mitochondrial coding genes of C. maxima exhibited an average GCall content of 42.57%, with the last position enriched in A/T bases. Codon usage analysis indicated weak codon bias, with the effective codon number (ENC) ranging from 44.22 to 61.00. Correlation analysis and neutrality plot analysis demonstrated a nonsignificant correlation between GC3 and GC12. PR2-plot and ENC-plot analysis further supported the influence of natural selection on the codon preference in the C. maxima mitochondrial genome. Relative synonymous codon usage (RSCU) analysis identified 19 optimal codons, with a preference for U or A as the final base. The analysis of scattered repeat sequences in the genome indicated a high frequency of forward and palindromic repeats in the C. maxima mitochondrial genome. Nucleic acid diversity analysis highlighted rpl5 as the gene with the highest variability. Comparative analysis of mitochondrial structure and phylogenetic tree analysis revealed a close evolutionary relationship between C. maxima and Cucurbita pepo, showing synteny in evolution. Homologous fragment analysis demonstrated a similarity of over 70% between the C. maxima mitochondrial genome and chloroplast genome fragments. These findings provide a foundation for C. maxima identification and phylogenetic studies.

Queen Triggerfish Balistes vetula Age-Based Population Demographics and Reproductive Biology for Waters of the North Caribbean

Queen triggerfish Balistes vetula is an important reef-associated species for commercial fisheries in the U.S. Caribbean. It exhibits a relatively unique reproductive strategy as a nesting benthic spawner, investing substantial energy in territorial defense, building and maintaining nests, and caring for fertilized eggs during the reproductive season. Prior to this study, no comprehensive life history information existed in the literature for queen triggerfish. This study provides the first comprehensive documentation of age, growth, size/age at sexual maturity, reproductive seasonality, and reproductive output for a Balistes species in the Caribbean. From 2013 to 2023, we collected 2190 fish samples from fisheries-dependent and -independent sources from the waters of Puerto Rico and the U.S. Virgin Islands. Fish ranged from 67 to 477 mm fork length (FL). We documented that queen triggerfish is sexually dimorphic with males attaining larger mean sizes-at-age compared to females and the species is characterized by a moderately young age at median sexual maturity (A50 = 3.3 y). The maximum age for our U.S. Caribbean samples was 23 y based on increment counts from otoliths. Spawning season encompassed the months of December to August in the region, and female spawning frequency ranged from an estimated 2 to 84 times per year; female spawning frequency increased with increasing size and age of fish. We documented that commercial fishers in the U.S. Caribbean mainly target “plate-size” individuals, defined in our study as 235–405 mm FL, which appears to act as a self-imposed slot size range limit and results in the fishery not removing individuals in the smallest and largest size groups at high rates. The percentage of immature fish from fisheries-dependent sources was close to 0 (0.8%). Commercial fishing for queen triggerfish in the region currently appears to be sustainable, but monitoring of the population should continue.

Spatial and temporal distribution of juvenile Gulf Sturgeon in the Pearl River, Louisiana, and adjacent estuaries of the Gulf of Mexico

AbstractObjectiveAcoustic telemetry was used to examine the spatial‐temporal distribution and anadromous migration pattern of juvenile Gulf Sturgeon Acipenser desotoi within the Pearl River and associated coastal estuaries of Louisiana and Mississippi.MethodsAcoustic transmitters were surgically implanted in 52 juvenile Gulf Sturgeon (&lt;890 mm fork length) from the Pearl River between 2016 and 2019. Sturgeon were monitored on 247 acoustic receivers in the lower Pearl River and adjacent estuaries across numerous partnering arrays.ResultJuveniles were detected on receivers from Lake Pontchartrain, Louisiana, east to Bay St. Louis, and Biloxi Bay, Mississippi. The 3‐year study found that juvenile Gulf Sturgeon migration in the Pearl River occurred on cycles similar to those reported from other populations. Juveniles were rarely observed in the estuary and nearshore marine environments from May through mid‐October of each year, during which time most sturgeon inhabited the Pearl River. Conversely, most of the juveniles inhabited coastal estuaries from December through February of each year and were rarely observed in freshwater environments during this period. Migration from the river into the estuary occurred during late‐October through November, and migration from the estuary into the river occurred in March and April. Distribution patterns varied spatially within the river and estuary ecosystems during each phase of migration. Tagged juveniles occupied the lowest 40 km of the Pearl River while in freshwater, and they occupied the northeastern shoreline of Lake Pontchartrain and Bay St. Louis while in the estuary. Interestingly, juveniles seemed to target specific areas in the estuary during winter that were farther away from the mouth of natal rivers than has been previously reported.ConclusionThis study provides a new assessment of juvenile Gulf Sturgeon migration and seasonal distribution for the Pearl River and provides important information for designing and assessing the potential benefits and challenges of habitat restoration for Gulf Sturgeon.

Assessment of Long-Term Success and Survival Rates of Different Types of Intracanal Medicaments.

Antimicrobial endodontic intracanal medicaments play a vital role along with biomechanical preparation in the elimination of bacteria present in the pulp area to achieve success in endodontic therapy. The present research was conducted with the objective of evaluating and comparing intracanal medicaments regarding antibacterial properties against Enterococcus faecalis. One hundred and twenty healthy human premolars of the mandible were used. All premolar crowns were removed, keeping the standardized length of the root as 15 mm. Category 1 received triple antibiotic paste (TAP) (n = 30), Category 2 received double antibiotic paste (DAP) (n = 30), Category 3 received augmentin (n = 30), and Category 4 received calcium hydroxide (n = 30). Hygienic paper points were placed in each root canal, then they were moved to a tube containing 1 mL of brain-heart infusion medium and left there for bacteriological testing. Colony-forming units (CFUs) of E. faecalis were then observed and counted after the plates had been incubated overnight at a temperature of 37°C. During intracategory comparisons, there was a significant reduction in colonies of E. feacilis in each category (P ≤ 0.001). When there were intercategory comparisons, there was a maximum reduction in CFU in specimens of Category 1 (TAP) followed by Category 3 (Augmentin) and Category 2 (DAP). Intracanal medicaments like TAP, DAP, and augmentin are effective against root canal E. faecalis.

Characterization of sound production by the pot-bellied seahorse (Hippocampus abdominalis) during feeding.

Sound production during feeding by the pot-bellied seahorse, Hippocampus abdominalis, was quantified with an observation of clicks (acoustic signal) and snicks (visual behavior). Female, male, and juvenile seahorses had feeding sounds characterized for peak (dominant) frequency (Hz), sound pressure level (SPL), and duration (ms). Subject body size and condition was estimated by standard length (SL, cm), to determine an estimate of body condition index (BCI). An inverse correlation between mean peak frequency (Hz) of clicks and SL was found for females. A negative correlation between peak frequency (Hz) of clicks and a residual BCI was determined for both males and females, suggesting that acoustic signals may contain information regarding fitness.

Seeing further into the early steps of the endangered atlantic goliath grouper (Epinephelus itajara): Eye lenses high resolution isotopic profiles reveal ontogenetic trophic and habitat shifts

Estuarine mangroves are often considered nurseries for the Atlantic Goliath grouper juveniles. Yet, the contributions of different estuarine primary producers and habitats as sources of organic matter during early ontogenetic development remain unclear. Given the species’ critically endangered status and protection in Brazil, obtaining biological samples from recently settled recruits in estuaries is challenging. In this study, we leveraged a local partnership with fishers and used stable isotope (C and N) profiles from the eye lenses of stranded individuals or incidentally caught by fishery to reconstruct the trophic and habitat changes of small juveniles. The eye lens grows by the apposition of protein-rich layers. Once these layers are formed, they become inert, allowing to make inferences on the trophic ecology and habitat use along the development of the individual until its capture. We used correlations between fish size and the entire eye lens size, along with estuarine baselines, to reconstruct the fish size and trophic positions for each of the lens layers obtained. We then used dominant primary producers and basal sources from mangrove sheltered, exposed estuarine and marine habitats to construct an ontogenetic model of trophic and habitat support changes since maternal origins. Our model revealed marine support before the juveniles reached 25 mm (standard length), followed by a rapid increase in reliance on mangrove sheltered sources, coinciding with the expected size at settlement. After reaching 60 mm, individuals began to show variability. Some remained primarily supported by the mangrove sheltered area, while others shifted to rely more on the exposed estuarine area around 150 mm. Our findings indicate that while mangroves are critical for settlement, as Goliath grouper juveniles grow, they can utilize organic matter produced throughout the estuary. This underscores the need for conservation strategies that focus on seascape connectivity, as protecting just one discrete habitat may not be sufficient to preserve this endangered species and safeguard its ecosystem functions.

The true complexities of "standard" family practice visits unmasked: an observational cross-sectional study in Regina.

Many patients present to their family medicine clinic with more than one health concern, placing an increased demand on family physicians. Research into the average number of concerns per regular family medicine visit is limited. Recognition of the frequency that family physicians address more than one concern per visit and adapting practices accordingly is important for improving patient care. To examine whether family physicians routinely address multiple different patient concerns during a single visit and if this is influenced by patient demographics. This study was conducted at a multi-physician family medicine clinic in Regina, Saskatchewan, Canada. Five physicians contributed their 500 most recent charts, extending retrospectively from 1 June 2023, from in-person visits by patients over 18 years of age and billed as regular appointments without billed procedures. Each chart was reviewed for the number of concerns addressed in the visit. Fifty percent of visits addressed more than 1 concern (range = 1-8). A generalized linear mixed model using Poisson distribution showed certain physicians (incident rate ratio [IRR]: 1.192, 95% CI: 1.087-1.307, P < 0.001) and adults older than 65 years compared to adults less than 40 years (IRR 1.151, 95% CI: 1.069-1.239, P < 0.001) were more likely to present with multiple concerns, but patient sex was not a significant predictor. Family physicians routinely address more than one concern per visit. Standard visit length and billing practices should be adapted to reflect this complexity.

Depressive symptom trajectories with prolonged rTMS treatment

BackgroundA prolonged repetitive transcranial magnetic stimulation (rTMS) treatment course could be beneficial for some patients experiencing major depressive episodes (MDE). We identified trajectories of rTMS response in depressive patients who received an extended rTMS treatment course and sought to determine which trajectories achieved the greatest benefit with a prolonged treatment course. MethodWe applied group-based trajectory modeling to a naturalistic dataset of depressive patients receiving a prolonged course of sequential bilateral rTMS (up to 51 treatment sessions) to the dorsolateral prefrontal cortex. Trajectories of the PHQ-9 with extended treatment courses were characterized, and we explored the association between baseline clinical characteristics and group membership using multinomial logistic regression. ResultsAmong the 324 study participants, four trajectories were identified: “linear response, extended course” (N = 73; 22.5 %); “nonresponse” (N = 23; 7.1 %); “slowed response” (N = 159; 49.1 %); “rapid response, standard treatment length” (N = 69; 21.3 %). Only the “linear response, extended course” group showed considerable clinical improvement after receiving additional rTMS treatments. Greater baseline depressive symptoms were associated with linear response and non-response. ConclusionOur results confirmed the distinctive response trajectories in depressive patients receiving rTMS and further highlighted that prolonged rTMS treatment courses may be beneficial for a subset of patients with higher initial symptom levels and linear early treatment response.

Size structure, age, and growth of the blue shark, Prionace glauca (Linnaeus, 1758) in southern Brazil.

The blue shark is a highly migratory species with a worldwide distribution, making it susceptible to multiple fishing fleets across the globe. In southern Brazil, it is an important target, comprising up to 40% of the total biomass landed by the commercial surface longline fleet. This study aims to contribute to a better understanding of how the species uses the region and to update its life-history information available for future assessments. Over five consecutive years (2018-2022) of landings and onboard monitoring, we gathered size data and vertebral samples to describe the species size composition in the region, as well as its seasonal and interannual variability and to update estimated life-history parameters. The results showed that southern Brazil is mainly inhabited by large juvenile males that arrive during winter (July-September) and stay until spring (October-December), when their frequency decreases. Small adult males are present throughout the year but in higher frequencies during summer. A small number of adult females are present with higher frequencies during spring and summer, which decreases during the austral autumn and winter. Some variability in the presence of each life stage was observed among years. The estimated life-history parameters were as follows: L∞: 255.02 cm fork length (FL), k: 0.20, L0:35.68 cm FL for males; L∞: 246.47 cm FL, k: 0.23, L0:36.77 cm FL for females; and L∞: 269.58 cm FL, k: 0.18, L0:36.19 cm FL for pooled sexes. However, the estimated values must be cautiously interpreted, as the obtained samples cannot be construed as representative of the entire harvested stock due to the lack of consistent presence of some life stages in the study region.

Equivalent revision rates and patient reported outcomes with routine use of a short (125mm) cemented stem for total hip arthroplasty compared to a standard length (150mm) cemented stem. A two surgeon series of 1335 patients.

Routine total hip arthroplasty (THA) using a short cemented stem as compared with a standard length cemented stem may have benefits in terms of stress distribution, bone preservation, stem subsidence and ease of revision surgery. Two senior arthroplasty surgeons transitioned their routine femoral implant from a standard 150mm Exeter V40 cemented stem to a short 125mm Exeter V40 cemented stem for all patients over the course of several years. We analysed revision rates, adjusted survival, and PROMS scores for patients who received a standard stem and a short stem in routine THA. All THAs performed by the two surgeons between January 2011 and December 2021 were included. All procedures were performed using either a 150mm or 125mm Exeter V40 stem. Demographic data, acetabular implant type, and outcome data including implant survival, reason for revision, and post-operative Oxford Hip Scores were obtained from the New Zealand Joint Registry (NZJR), and detailed survival analyses were performed. Primary outcome was revision for any reason. Reason for revision, including femoral or acetabular failure, and time to revision were also recorded. 1335 THAs were included. 516 using the 150mm stem and 819 using the 125mm stem. There were 4055.5 and 3227.8 component years analysed in the standard stem and short stem groups respectively due to a longer mean follow up in the 150mm group. Patient reported outcomes were comparable across all groups. Revision rates were comparable between the standard 150mm stem (0.44 revisions/100 component years) and the short 125mm stem (0.56 revisions/100 component years) with no statistically significant difference found (p = 0.240). Routine use of a short 125mm stem had no statistically significant impact on revision rate or PROMS scores when compared to a standard 150mm stem. There may be benefits to routine use of a short cemented femoral implant.

Heritability and predictive ability for the heterobothriosis resistance and growth performance in the tiger pufferfish Takifugu rubripes fed standard or low fishmeal diets

Heterobothriosis resistance and high growth performance are major concerns in the tiger pufferfish (Takifugu rubripes) farming. Our previous small-scale study suggested the feasibility of genomic selection (GS) for these traits but also identified an undesired genetic correlation between them, which could hamper simultaneous genetic improvement. Here, we sought to validate these initial findings through larger samples and crosses and also explore the potential of GS for the individuals fed a normal fishmeal diet and a low fishmeal (LFM) diet. We produced three populations: one was fed a normal diet (PopFM: 1100 individuals) and two were fed an LFM diet (PopLFM1: 993 individuals; PopLFM2: 1017 individuals); all three populations were artificially infected with Heterobothrium okamotoi, a monogenean parasite causing heterobothriosis. We recorded standard lengths of the fish after artificial infection (SLEAI) and the number of parasites on the gill cavity wall (HC) and genotyped genome-wide single nucleotide polymorphisms (SNPs) using genotyping by random amplicon sequencing, direct (GRAS-Di) technology for each sample: PopFM, 12 K SNPs; PopLFM1, 19 K SNPs; PopLFM2, 21 K SNPs. Heritability and prediction ability for each trait were estimated for each population using genomic best linear unbiased prediction (GBLUP), Bayes C, and Bayesian ridge regression methods. SNP effects on each trait were estimated by Bayes C, Bayesian ridge regression, and genome-wide association analyses (GWAS) using the same data sets. We observed moderate to high levels of heritability for HC (0.16–0.57) and SLEAI (0.50–0.77), with predictive ability of 0.25–0.55 for HC and of 0.51–0.73 for SLEAI. These values were slightly larger in LFM diet groups. As reported previously, a weak undesired genetic correlation was observed between the traits, and the correlation was more pronounced in the LFM groups. In conclusion, our results indicate that genetic gain in growth and parasite resistance traits can be expected for the tiger pufferfish through GS, especially for individuals reared on an LFM diet. However, close attention should be paid to the extent of the undesirable genetic correlation between the two traits that may be amplified in the populations fed an LFM diet.

Predicting juvenile-to-adult survival in Chinook salmon using non-lethal scale-derived growth and regeneration indices

ABSTRACT Survival is often associated with body size, growth rate, and stress, but the latter two are more difficult to observe non-lethally. Non-lethal methods can be particularly important for endangered and culturally valuable species. With fish scales, growth and stress indices could be inferred without needing to sacrifice fish. We examined scales from ~350 wild Chinook salmon (Oncorhynchus tshawytscha) in Valley Creek and at Lower Granite Dam (Pacific Northwest, USA) in 2007–2019. From a von Bertalanffy model and scale circulus spacings, we estimated a brood-year-specific growth coefficient K (hereafter K ˆ ). Using the scale-derived K ˆ and other biological and environmental covariates, we examined how these potential predictors associated with juvenile-to-adult survival of >136,000 passive-integrated-transponder-tagged Chinook salmon from the Snake River Basin (Pacific Northwest, USA). We found that the effects on survival from brood-year-specific K ˆ , fork length of the tagged individuals, and interaction between K ˆ and fork length were positive. We also determined that the proportion of fish samples with regenerated scales (an indicator of stress) had a negative effect on survival. For further refinement of non-lethal, scale-derived indices on survival, we encourage examination of indices across populations, juvenile habitats, and juvenile life stages, and not simply a regional, brood-year-specific growth index.

Establishment of Bull Trout in a previously fishless subalpine lake by translocation

AbstractObjectiveTranslocations have increased in recent years to aid in species recovery efforts. This includes translocations outside of species' historical distribution, where threats are less severe. One candidate species for translocation is the Bull Trout Salvelinus confluentus, but few examples of successful translocations (re‐establishment or range expansion) have been documented. Here, we describe an example in which 63 Bull Trout were translocated in 1987 to establish a population in fishless Marie Lake, Alberta.MethodsThe translocation was monitored through multiple sampling events over the course of 33 years. Sampling techniques included backpack electrofishing, angling, and water quality and habitat assessments.ResultA population estimate suggested that Bull Trout increased by at least fourfold over the first 12 years; fish reached large sizes (692 mm fork length) and old ages (13 years), and the population had multiple age‐ and length‐classes, including juveniles. Bull Trout also had become established within at least 13 km of river outside of Marie Lake by 2019.ConclusionAlthough a naturally reproducing population of this at‐risk species was established, numerous factors were not considered within this translocation initiative. Most importantly, nonadfluvial Bull Trout from a disparate source population located about 4000 river kilometers away were used for the translocation. Our case study represents a rare example of a successful Bull Trout translocation and highlights considerations that should occur prior to future translocations that are intended to aid in species recovery and preservation.

452 Leg Flexion to Overcome Gaps for Direct Sciatic Nerve Repair: An Anatomic Study

INTRODUCTION: Direct nerve repairs fare better than grafted nerves, especially for large caliber nerves. Numerous surgical techniques are used to achieve tension-free end-to-end repairs for large gaps in the sciatic nerve (SN) and common peroneal nerve (CPN), including distal nerve mobilization, transposition, side-branch neurectomy, or even shortening of the femur with distraction osteogenesis. However, leg flexion with serial distraction is the simplest, least morbid, and most easily implemented technique. METHODS: Eight fresh cadavers with pelvis intact were dissected to determine the relationship between degrees of knee flexion (ranged from 0 to 90-degree flexion) and the gap length overcome with nerve excursion. Additional excursion from SN side-branch neurectomy was also assessed. RESULTS: We found an approximately linear relationship between knee flexion and nerve excursion. In the mid-thigh there was 7-9 mm of SN excursion per 10 degrees of flexion, and 10-11 mm of SN excursion per 10 degrees of flexion with neurectomy. There was 11-13 mm of CPN excursion per 10 degrees of flexion in the distal half of the thigh. CONCLUSIONS: Knee flexion can significantly augment the ability to achieve an end-to-end repair of the SN and CPN. Simplified, each 10 degrees of knee flexion provides about 1 cm of additional length for both nerves, which is essentially constant throughout the arc of flexion. Neurectomy allows approximately 1-2 cm in total additional length at full flexion in fresh cadavers. Approximately 10 cm total excursion can be gained at 90-degree knee flexion with side-branch neurectomies. We recommend 45-90 days of progressive extension to respect the safe regeneration timing of 1-2 mm/day from a repair performed with 90-degree knee flexion.