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Introduction We recently developed two noninvasive methodologies to help guide VT ablation: population-derived automated VT exit localization (PAVEL) and virtual-heart arrhythmia ablation targeting (VAAT). We hypothesized that while very different in their nature, limitations, and type of ablation targets (substrate-based vs. clinical VT), the image-based VAAT and the ECG-based PAVEL technologies would be spatially concordant in their predictions. Objective The objective is to test this hypothesis in ischemic cardiomyopathy patients in a retrospective feasibility study. Methods Four post-infarct patients who underwent LV VT ablation and had pre-procedural LGE-CMRs were enrolled. Virtual hearts with patient-specific scar and border zone identified potential VTs and ablation targets. Patient-specific PAVEL based on a population-derived statistical method localized VT exit sites onto a patient-specific 238-triangle LV endocardial surface. Results Ten induced VTs were analyzed and 9-exit sites were localized by PAVEL onto the patient-specific LV endocardial surface. All nine predicted VT exit sites were in the scar border zone defined by voltage mapping and spatially correlated with successful clinical lesions. There were 2.3 ± 1.9 VTs per patient in the models. All five VAAT lesions fell within regions ablated clinically. VAAT targets correlated well with 6 PAVEL-predicted VT exit sites. The distance between the center of the predicted VT-exit-site triangle and nearest corresponding VAAT ablation lesion was 10.7 ± 7.3 mm. Conclusions VAAT targets are concordant with the patient-specific PAVEL-predicted VT exit sites. These findings support investigation into combining these two complementary technologies as a noninvasive, clinical tool for targeting clinically induced VTs and regions likely to harbor potential VTs.

Background Mediator is a multiprotein complex that acts as an essential transcriptional coactivator in eukaryotic cells for successful transcription. In this study, we aimed to explore the expression profile of 33 mediator subunit genes in oral cavity squamous cell carcinoma (OCSCC) and the functional role of MED28 in cellular behaviors of OCSCC cells. Methods Single-cell (sc)RNA-seq data from OCSCC cells (Puram 2017's dataset) and bulk-seq data of the OCSCC subgroup of TCGA-head and neck squamous cell carcinoma (HNSC) were used for bioinformatic analysis. SCC9 cells were used in in-vitro and in-vivo analysis. Results Among the 33 genes subjected to screening, MED28 showed the best prognostic value and its upregulation might independently predict shorter OS (HR: 3.699, 95% CI: 1.383-9.892, P = .009) and PFS (HR: 2.769, 95% CI: 1.462-5.244, P = .002). MED28 expression was positively correlated with cancer stem cell (CSC)-like properties of SCC9 cells, including colony/sphere formation, and the expression of CSC markers (CD44, KLF4, NANOG, and OCT4). RCOR1 could suppress the CSC-like properties of SCC9 cells and had direct interaction with MED28. Its overexpression partly abrogated MED28-induced expression of CSC markers. RCOR1 expression was associated with promoter hypermethylation, while MED28 expression was positively correlated with its MED28 copy number (Pearson's r = .44) in OCSCC tissues. Conclusion Among the mediator complex subunits, MED28 might serve as a potential biomarker of unfavorable survival. Its overexpression increased CSC-like activity of OCSCC cells, the effect of which could be abrogated by RCOR1 via direct interaction.

The Cancer Genome Atlas (TCGA) Research Network confirmed that undifferentiated pleomorphic sarcoma (UPS) and myxofibrosarcoma (MFS) share a high level of genomic similarities and fall into a single spectrum of tumour. However, no molecular prognostic biomarkers have been identified in UPS/MFS. In this study, by extracting data from TCGA‐Sarcoma (SARC), we explored relapse‐related genes, their prognostic value and possible mechanisms of the dysregulations. After systematic screening, ITGA10 and PPP2R2B were included to construct a 2‐gene signature. The 2‐gene signature had an AUC value of 0.83 and had an independent prognostic value in relapse‐free survival (RFS) (HR: 2.966, 95%CI: 1.995‐4.410 P .4) with PPP2R2B expression. Besides, the 2‐gene signature showed a moderate negative correlation with CD4 + T cell infiltration. High‐level CD4 + T cell infiltration and neutrophil infiltration were associated with significantly better RFS. Based on these findings, we infer that the 2‐gene signature might be a potential prognostic marker in patients with UPS/MFS. Considering the potential benefits of immunotherapy for UPS/MFS patients, it is imperative to explore the predictive value of this signature in immunotherapeutic responses in the future.

DDR1 has been identified as a cancer-associated receptor tyrosine kinase that is highly expressed in several malignancies relative to normal tissues. Clinically approved multi-kinase inhibitors, such as nilotinib, inhibit DDR1-mediated tumor growth in xenograft models, suggesting DDR1 might be a potential target for cancer treatments. Here, we employed an antibody-based strategy with a novel anti-DDR1 antibody-drug conjugate (ADC) for colon carcinoma treatment. We developed T4 H11 -DM4, an ADC targeting DDR1 which carries the tubulin inhibitor payload DM4. Immunohistochemical analysis of a tissue microarray containing 100 colon cancer specimens revealed that DDR1 was highly expressed in 81% of tumor tissues. Meanwhile, high expression of DDR1 was associated with poor survival in patients. In vitro, T4 H11 -DM4 exhibited potent anti-proliferative activity with half maximal inhibitory concentration (IC50 ) values in the nanomolar range in a panel of colon cancer cell lines. In vivo, the antitumor efficacy of T4 H11 -DM4 was evaluated in three colon cancer cell lines expressing different levels of DDR1. T4 H11 -DM4 achieved complete tumor regression at doses of 5 and 10 mg·kg-1 in HT-29 and HCT116 tumor models. Moreover, a correlation between in vivo efficacy of T4 H11 -DM4 and the levels of DDR1 expression on the cell surface was observed. Tumor cell proliferation was caused by the induction of mitotic arrest, indicating that the antitumor effect in vivo was mediated by DM4. In addition, T4 H11 -DM4 was efficacious in oxaliplatin-resistant colon cancer models. In exploratory safety studies, T4 H11 -DM4 exhibited no overt toxicities when multi-doses were administered at 10 mg·kg-1 into BALB/c nude mice or when a single dose up to 50 mg·kg-1 was administered into BALB/c mice. Overall, our findings highlight the potential of DDR1-targeted ADC and may facilitate the development of a new effective therapeutic strategy for colon cancer.

BACKGROUND It has been reported that there are more circulating tumor cells (CTCs) in the pulmonary vein (PV) than in the peripheral blood; however, it is unclear whether the CTC count changes in the PV after resection of a lung lobe. METHODS Thirty-three lung cancer patients were recruited for the study, including 17 who underwent lobectomy via video-assisted thoracoscopic surgery and 16 via open thoracotomy. Sixty-six blood specimens were sampled from the PV before the PV was interrupted and after lobectomy. The CTCs were quantified using the oHSV1-hTERT-GFP method. RESULTS Before PV interruption, the CTC (pre-CTC) detection rate was 79.0% (26/33), the mean number of CTCs was 3.36 (median 2, range: 0-18), and there was no significant relationship between the pre-CTC count and clinical factors, such as histologic findings and pathological T stage (P > 0.05). After lobectomy, the CTC (post-CTC) detection rate was 100% (33/33), the average number of CTCs was 14.88 (median 11, range: 1-69), and the post-CTC count was significantly higher in patients in whom the PV was interrupted prior to the pulmonary artery (PA) than in patients in whom the PA was interrupted before the PV (P = 0.016). Overall, the CTC count was significantly higher following surgery (P < 0.001). CONCLUSION Post-CTC counts were significantly higher than pre-CTC counts, suggesting that surgical manipulation may potentially dislodge tumor cells into the PV. Interrupting the PV prior to the PA during lobectomy may prevent partial CTC entry into the circulation.

5′‐Nucleotidase Domain Containing 2 (NT5DC2) is a novel oncoprotein, the regulatory effects of which have not been well characterized. This study aimed to investigate the expression profile and functional regulation of NT5DC2 and its potential interplay with TEAD4 in leiomyosarcoma (LMS). Bioinformatic analysis was conducted using data from The Cancer Genome Atlas (TCGA) and Genotype‐Tissue Expression (GTEx) program. LMS cell lines SK‐LMS‐1 and SK‐UT‐1 were used for both in vitro and in vivo analysis. Results showed that NT5DC2 is aberrantly upregulated in LMS. Its overexpression was associated with unfavourable survival. Deletion of NT5DC2 significantly reduced the expression of cyclin B1, cyclin A2, cyclin E1 and CDK1 and increased G1 phase arrest in LMS cell lines, and suppressed their proliferation both in vitro and in vivo. NT5DC2 interacted with unpalmitoylated TEAD4, and this association reduced TEAD4 degradation via the ubiquitin‐proteasome pathway. TRIM27 is a novel E3 ubiquitin ligase that induces K27/48‐linked ubiquitination of unpalmitoylated TEAD4 at Lys278. TEAD4 inhibition significantly suppressed LMS cell growth both in vitro and in vivo. Dual‐luciferase assay demonstrated that TEAD4 could bind to the NT5DC2 promoter and activate its transcription. Based on these findings, we infer that the NT5DC2‐TEAD4 positive feedback loop plays an important role in LMS development and might serve as a potential therapeutic target.

BACKGROUND AND OBJECTIVES Catheter ablation of ventricular tachycardia (VT) may include induction of VT and localization of VT-exit site. Our aim was to assess localization performance of a novel statistical pace-mapping method and compare it with performance of an electrocardiographic inverse solution. METHODS Seven patients undergoing ablation of VT (4 with epicardial, 3 with endocardial exit) aided by electroanatomic mapping underwent intraprocedural 120-lead body-surface potential mapping (BSPM). Two approaches to localization of activation origin were tested: (1) A statistical method, based on multiple linear regression (MLR), which required only the conventional 12-lead ECG for a sufficient number of pacing sites with known origin together with patient-specific geometry of the endocardial/epicardial surface obtained by electroanatomic mapping; and (2) a classical deterministic inverse solution for recovering heart-surface potentials, which required BSPM and patient-specific geometry of the heart and torso obtained via computed tomography (CT). RESULTS For the MLR method, at least 10-15 pacing sites with known coordinates, together with their corresponding 12-lead ECGs, were required to derive reliable patient-specific regression equations, which then enabled accurate localization of ventricular activation with unknown origin. For 4 patients who underwent epicardial mapping, the median of localization error for the MLR was significantly lower than that for the inverse solution (10.6 vs. 27.3 mm, P = 0.034); a similar result held for 3 patients who underwent endocardial mapping (7.7 vs. 17.1 mm, P = 0.017). The pooled localization error for all epicardial and endocardial sites was also significantly smaller for the MLR compared with the inverse solution (P = 0.005). CONCLUSIONS The novel pace-mapping approach to localizing the origin of ventricular activation offers an easily implementable supplement and/or alternative to the preprocedure inverse solution; its simplicity makes it suitable for real-time applications during clinical catheter-ablation procedures.

The purpose of this study was to figure out the effect of ciRS‐7/miR‐7/NF‐κB axis on the development of non‐small cell lung cancer (NSCLC). In response, the expressions of ciRS‐7, miR‐7 and NF‐κB subunit (ie RELA) within NSCLC tissues and cell lines were determined with real‐time polymerase chain reaction (RT‐PCR) and Western blot. Moreover, the NSCLC cells were transfected with pcDNA3‐ciRS‐7‐ir, pcDNA3‐ciRS‐7, miR‐NC and miR‐7 mimic. Furthermore, the targeted relationships between ciRS‐7 and miR‐7, as well as between miR‐7 and RELA, were confirmed by luciferase reporter assay. The proliferation, migration and apoptosis of NSCLC cells were, successively, measured using CCK‐8 assay, wound‐healing assay and flow cytometry test. Consequently, ciRS‐7, miR‐7, histopathological grade, lymph node metastasis and histopathological stage could independently predict the prognosis of patients with NSCLC (all P < .05). Moreover, remarkably up‐regulated ciRS‐7 and RELA expressions, as along with down‐regulated miR‐7 expressions, were found within NSCLC tissues and cells in comparison with normal ones (P < .05). Besides, overexpressed ciRS‐7 and underexpressed miR‐7 were correlated with increased proliferation, migration and invasion, yet reduced apoptosis rate of NSCLC cells (P < .05). More than that, ciRS‐7 specifically targeted miR‐7 to reduce its expressions (P < .05). Ultimately, the NSCLC cells within miR‐7 + RELA group were observed with superior proliferative, migratory and invasive capabilities than those within miR‐7 group (P < .05), and RELA expression was also significantly modified by both ciRS‐7 and miR‐7 (P < .05). In conclusion, the ciRS‐7/miR‐7/NF‐kB axis could exert pronounced impacts on the proliferation, migration, invasion and apoptosis of NSCLC cells.

The degree to which a stock is depleted is one of the most important quantities in fisheries management because it is used to quantify the success of management and to inform management responses. However, stock depletion is extremely difficult to estimate, particularly with limited data. Using the RAM Legacy database, we developed a boosted regression tree (BRT) model to correlate depletion with a range of predictors calculated from catch data, making the model usable for many fisheries worldwide. The most important predictors were found to be catch trends obtained from linear regressions of scaled catch on time, including regression coefficients for the whole catch time series, the subseries before and after the maximum catch, and in recent years. Eight predictors explain about 80% of variation in depletion. There is a correlation of .5 between measured levels of depletion and the predictions of the BRT model. Predictions are less biased when the stock is fished down below half of the carrying capacity. The BRT model outperforms comparable existing catch-based depletion estimators and could be used to provide priors for depletion for data-poor stock assessment methods, or used more directly to provide estimates of the probability that depletion is below a given threshold value.

Perovskite solar cells (PSCs) have witnessed astonishing improvement in power conversion efficiency (PCE), more recently, with advances in long‐term stability and scalable fabrication. However, the presence of an anomalous hysteresis behavior in the current density–voltage characteristic of these devices remains a key obstacle on the road to commercialization. Herein, sol–gel‐processed mesoporous boron‐doped TiO2 (B‐TiO2) is demonstrated as an improved electron transport layer (ETL) for PSCs for the reduction of hysteresis. The incorporation of boron dopant in TiO2 ETL not only reduces the hysteresis behavior but also improves PCE of the perovskite device. The simultaneous improvements are mainly ascribed to the following two reasons. First, the substitution of under‐coordinated titanium atom by boron species effectively passivates oxygen vacancy defects in the TiO2 ETL, leading to increased electron mobility and conductivity, thereby greatly facilitating electron transport. Second, the boron dopant upshifts the conduction band edge of TiO2, resulting in more efficient electron extraction with suppressed charge recombination. Consequently, a methylammonium lead iodide (MAPbI3) photovoltaic device based on B‐TiO2 ETL achieves a higher efficiency of 20.51% than the 19.06% of the pure TiO2 ETL based device, and the hysteresis is reduced from 0.13% to 0.01% with the B‐TiO2 based device showing negligible hysteresis behavior.

Gardner's syndrome is a hereditary disorder inherited as an autosomal dominant with high penetrance and variable expression that is caused by a mutation of the adenomatous polyposis coli gene. It is characterized by gastrointestinal polyps associated with multiple osteomas, dental anomalies, and skin and soft tissue tumors. We present a case of 30-year-old female patient with Gardner's syndrome who presented with a giant mediastinal thymolipoma. The tumor was completely excised through a bilateral posterolateral thoracotomy. There was no recurrence after 20 months of follow-up. We therefore suggest that physicians who regularly treat patients with Gardner's syndrome carefully examine for thoracic manifestations.

The world's seas and oceans are a vital source of animal protein from fishing and a major contributor to global food security. It has been argued that global wild-catch production has reached its limit, and there is concern that many species are overfished. Concerns are also mounting about the state of marine ecosystems and the ecological impacts of fishing on them, with increasing efforts to protect marine biodiversity. Fisheries appear to be at an impasse – demand for seafood is rising but so is concern about the impacts of fishing. However, through a simple analysis, we show that global exploitation rates are well below long-term sustainable levels at a whole ecosystem level. The oceans can support considerably higher sustainable catch than currently harvested. Overfishing has happened but only to a small fraction of species as a result of intensive and selective fishing. Shifting fishing effort away from highly targeted stocks towards currently underutilized species would reduce pressure on overfished species, result in fewer adverse ecosystem effects of fishing and increase overall fisheries production. This shift requires significant changes to our views about seafood, particularly in the developed world. We suggest ways in which this paradigm shift could happen and the range of expertise that would be required to achieve higher global yields with less ecological impact.

Summary Many population dynamics models and common software packages, including for capture–mark–recapture, occupancy and catch-at-age models, are estimable using parameters that are either constant for all years or vary annually. We develop a spline approximation to time-varying parameters, which includes the constant or annually varying case as two extremes, where the Akaike Information Criterion is used to select an appropriate degree of smoothness, ranging from change in every year to no change at all. Simulation modelling is used to evaluate the performance of this method relative to constant, annually varying, or random-effect parameter estimates when applied to an occupancy model that simultaneously estimates abundance and detectability in multiple sampling strata. We also demonstrate this method by approximating time-varying abundance using 25 years of detection/non-detection data for 42 Chondrichthyes species off northern Australia. Simulation modelling indicates that the stepwise-spline approximation results in lower estimation errors for the proportion of abundance in each stratum, regardless of sample sizes, the underlying form for time-varying abundance and the inclusion of unmodelled process errors. Applied to the Chondrichthyes data from northern Australia, the spline approximation identifies temporal variability in abundance for 34 of 42 species, and an annually varying model is never selected. We recommend this stepwise-spline approximation in cases where a decision is necessary between constant or annually varying forms for an estimated parameter. Possible applications include occupancy, capture–mark–recapture, catch-at-age and index standardization models.

The combination of cilostazol, aspirin, and clopidogrel (triple therapy) after percutaneous coronary intervention has been considered as an alternative therapy. We performed a meta‐analysis based on 8 randomized controlled trials with a total of 3332 patients to compare the effectiveness and safety of this triple therapy with traditional dual therapy (aspirin and clopidogrel). Our findings suggested that the triple therapy is more effective than dual therapy in preventing restenosis (odds ratio [OR]: 0.52, 95% confidence interval [CI]: 0.40–0.66, P < 0.00001), maintaining minimal lumen diameter (OR: 0.15, 95% CI: 0.10–0.20, P < 0.00001), and avoiding target‐vessel revascularization (OR: 0.62, 95% CI: 0.47–0.82, P = 0.001). There is also no significant difference in major adverse cardiac and cerebrovascular events between the 2 therapies, except the smaller occurrence rate of target‐lesion revascularization in the triple‐therapy group (OR: 0.42, 95% CI: 0.26–0.69, P = 0.0005). However, the triple therapy is associated with a higher level of adverse drug events, including rash (OR: 2.45, 95% CI: 1.41–4.23, P = 0.001), gastrointestinal disorders (OR: 2.59, 95% CI: 1.26–5.30, P = 0.009), and drug discontinuation (OR: 3.80, 95% CI: 1.59–9.10, P = 0.003), but it has no difference in bleeding compared with the dual therapy (OR: 1.05, 95% CI: 0.71–1.55, P = 0.80). Additional Supporting Information may be found in the online version of this article. Ping Wang, MS and Shijie Zhou, MS contributed equally to this article. The authors have no funding, financial relationships, or conflicts of interest to disclose.

Hepatitis B virus (HBV) infection is the leading cause of liver cirrhosis and hepatocellular carcinoma worldwide. In recent decades, significant progress toward understanding the molecular virology and pathogenesis of HBV infection has been made. In addition, multiple treatment modalities have been developed for persons with HBV infection. In the present study, we demonstrated that IL-4 inhibits the expression of hepatitis B surface antigen and hepatitis B e antigen in a HBV stably transfected hepatocellular carcinoma cell line (HepG2.2.15). To reveal the anti-HBV mechanism of IL-4 by proteomics, 2-DE and MS technology were utilized to profile global changes in protein expression in HepG2.2.15 cells after IL-4 treatment. A total of 56 differentially expressed proteins were identified in IL-4-treated HepG2.2.15 cells. To find out the interaction of these changed proteins by bioinformatics, signaling network analysis with the STRING tool showed that the identified proteins are primarily involved in transcription and proteolysis. Taken together, these results offer valuable clues for understanding the molecular mechanisms of the IL-4-mediated anti-HBV response.

The Australian Northern Prawn Fishery (NPF) is one of the few that has adopted a dynamic version of a ‘maximum economic yield’ (MEY) target, and, on this basis, the fishery is undergoing a process of substantial stock rebuilding. This study details the bioeconomic model used to provide scientific management advice for the NPF, in terms of the amount of allowable total gear length in the fishery, for both the MEY target and the path to MEY. It combines the stock assessment process for two species of tiger prawns with a specification for discounted economic profits, where the harvest function in the profit equation is stock-dependent. Results for the NPF show a substantial ‘stock effect’, indicating the importance of conserving fish stocks for profitability. MEY thus occurs at a stock size that is larger than that at maximum sustainable yield, leading to a ‘win-win’ situation for both the industry (added profitability) and the environment (larger fish stocks and lower impact on the ecosystem). Sensitivity results emphasize this effect by showing that the MEY target is much more sensitive to changes in the price of prawns and the cost of fuel, and far less so to the rate of discount.

By-catch and (or) discards in fisheries have been considered a serious problem and have been unanimously criticized by politicians, environmental groups, the public and scientists. However, it is possible to determine biologically acceptable amounts of discards that fulfil the objectives of ecosystem-based fishery management (EBFM). For instance, while discards have been shown to impact some systems negatively, they can be a potential benefit in other systems. Using a prawn trawl fishery as an example, this paper discusses some of the potentially positive effects of discards. As in many facets of EBFM, the key for the management of discards is sustainability and precaution. In particular, it is important to give full consideration to the implications of reducing discards to the lowest extent possible.

Estimating abundance is important in many ecological studies in order to understand the spatial and temporal dynamics of a population, which can assist in management and conservation. However, direct estimates of abundance can be difficult and expensive to obtain, particularly for wide-ranging, rare or elusive species. An alternative - estimating from detection-nondetection data - is a challenging but alluring concept to ecologists since the cost and effort of a study can be greatly reduced. This paper describes a method for estimating the abundance of randomly distributed or aggregated populations by using binary data where the probability of detection is less than one. The performances of the models were evaluated by computer simulations comprising 1620 cases. The results show that the accuracy of the abundance estimates increases as the sampling rate, efficiency of survey method, and the number of repeated surveys increase, whereas the accuracy declines as individuals become more aggregated. For a randomly distributed population, using a sampling rate of 0.05 in a survey method with a detection probability of 0.5, and repeating surveys three times provides sufficient accuracy of abundance. For an aggregated population, to achieve reasonably accurate abundance estimates the sampling rate should be doubled and each cell should be repeatedly surveyed on 4 to 6 occasions.

We investigated the effect of a hatchery program for summer steelhead Oncorhynchus mykiss on the productivity of a wild winter steelhead population in the Clackamas River, Oregon. We used a suite of Ricker and Beverton-Holt stock-recruitment models that incorporated species interaction variables to demonstrate that when high numbers of hatchery summer steelhead adults were present the production of wild winter steelhead smolts and adults was significantly decreased. We found that large releases of hatchery smolts also contributed to the decrease in wild adult productivity. Averaged over the results of our models, a 50% decline in the productivity parameter (the number of recruits per spawner at low densities) and a 22% decline in the maximum number of recruits produced in the basin were observed when high numbers of hatchery fish were present. We concluded that over the duration of the hatchery program, the number of hatchery steelhead in the upper Clackamas River basin regularly caused the total number of steelhead to exceed carrying capacity, triggering density-dependent mechanisms that impacted the wild population. The number of smolts and adults in the wild winter steelhead population declined until critically low levels were reached in the 1990s. Hatchery fish were removed from the system in 2000, and early results indicate that the declining trends have reversed.

A model was developed to estimate fishing-induced mortality and exploitation rates for unmarked salmon Oncorhynchus spp. in mark-selective fisheries. This model is analogous to a pipeline, and the basic idea is similar to that of the change-in-ratio method used for estimating animal abundance. During spawning migration, a unidirectional movement occurs from the ocean to near shore and into freshwater. A series of nonselective and selective fisheries consequently catch these fish on their migration path. The model functions as follows: First, a cohort analysis is completed for the coded-wire-tagged fish to obtain their initial abundance and fishery-specific exploitation rate. Second, fishery-specific exploitation rates of unmarked fish are derived. Third, the initial abundance of unmarked fish is obtained from the total exploitation rate and escapement and then the ratio between the abundances of unmarked and marked fish is estimated for each fishery. Finally, the fishery-specific mortality of unm...

Forecasts of the abundance and ocean escapement of Pacific salmon Oncorhynchus spp. are essential for fishery management. Based on data availability and quality, several forecasting methods have been used for different stocks. Data limitations have been an impediment to the use of formal statistical forecasting methods for many stocks. To date, the moving average (MA) of historical escapements has appeared to be the best choice for these stocks. I investigated the application of artificial neural networks (ANNs) to salmon escapement forecasting. I constructed ANNs with three layers (input, hidden, and output) and tested them with data from two stocks of Oregon coastal fall chinook salmon O. tshawytscha (the Siletz and Nehalem rivers) from 1986 to 2000. The outputs were compared with those of forecasts made with the traditional MA method. In addition, I analyzed the time series data with an autoregressive integrated moving average method (ARIMA). The ANNs generally outperformed the MA method for b...

Accurate estimation of the age and sex composition of Pacific salmon Oncorhynchus spp. is essential for understanding their population dynamics. Unfortunately, the data collected from spawning ground surveys are generally biased by the probability of recovery. Using 11 years of mark-recapture data for fall chinook salmon O. tshawytscha in the Salmon River, Oregon, I developed logistic models to examine the influences of stream flow and the sex and size of the fish on the probability of carcass recovery from spawning grounds. The results indicated no significant differences in recovery rates for males and females. The probability of recovery generally increased as fish size increased and as stream flow decreased. However, the relationships were nonlinear; the probability leveled off for very large fish and increased slightly at very high stream flow. Directly computed age and sex compositions from survey samples underestimated the ages of small fish and males while overestimating those of large fi...

In quantitative fisheries research, analysts often need to estimate the parameters of derived random variables that cannot be observed directly and are instead computed from other observed random variables. The delta method, which is based on the Taylor series, has been widely used for approximating the mean and variance of derived variables. This paper applies a computer simulation method that involves the parametric bootstrap method for estimating the mean and variance of derived random variables. The results from these two methods are compared with the true values (when they can be computed) or with each other. Several types of commonly used functions in quantitative fisheries studies are examined, namely, the exponential, logarithmic, product, quotient, and asymptotic functions. The parametric bootstrap method leads to fairly accurate estimates for the mean and variance of the derived variables. The delta method provides reasonably good estimates when the variation (expressed as the coefficie...

Mass marking of hatchery salmon and selective fisheries on these marked fish are being implemented in the northeastern Pacific Ocean. The potential impact of this management practice on current coded wire tag (CWT) programs has become a vital concern. Methods have been developed to maintain the viability of the current CWT programs by using double index tags (DITs). This study uses Monte Carlo simulations to examine uncertainty in estimating fishing mortality of unmarked coho salmon Oncorhynchus kisutch based on the DIT method. Variables used in the simulation include marine survival rate, encounter rate, hook-and-release mortality rate, precision in catch and escapement sampling, and harvest rate in nonselective fisheries. Results show that random variability in these variables creates significant uncertainty in the estimates. Typically, the 90% confidence interval of the estimated fishing mortality rate may take any value from below zero to more than double the true value. The precision of esti...

Recent declines in stocks of Tanner crab Chionoecetes bairdi in the Gulf of Alaska and Bering Sea and increases in the catch allocations of Pacific cod Gadus macrocephalus to vessels fishing pot gear have led to heightened concerns about Tanner crab bycatch. We conducted a laboratory study to examine the ability of two modifications in standard cod pots to reduce the catch of Tanner crabs compared with the standard pot. We also observed crab responses to a pot rigged with cod socks instead of cod triggers. In one modified pot, a slick plastic board was attached flush to the lower tunnel ramp of a pot (slick-board pot). In another modification, a webbed Z–K excluder horizontally divided the pot tunnel and three loose twine excluders were rigged on the tunnel eye (Z–K excluder pot). The plastic board on the slick-board pot deflected the current and led more crabs (32.4%) to approach side panels, rather than the tunnel eyes, compared with the standard pot (4.7%) and the Z-K excluder pot (7.9%). Both...

In trap fisheries, catch per trap haul changes with soak time. Catch rates should therefore be standardized for differences in soak time when used to measure abundance. Several models have been used to describe catch per trap haul while adjusting for soak time. Some of these models are limited with respect to time spent fishing or have difficulties in parameter estimation. In this paper, we describe a model without limitations on soak time. The model is Ct = ab + a(t – b)e–ct ; Ct is the catch per trap haul at soak time t; a, b, and c are parameters to be estimated. When sufficient data are used, the term ab denotes asymptotic catch after an infinite soak time, and a and c depend on local animal density, entry rate, and escape probability. These parameters can be readily estimated by many popular computer programs. This model is equivalent, or superior, to other models and is the only suitable model for long soak times with nonzero catch.