Yan Jiao

Virginia Tech (Virginia Polytechnic Institute and State University) | VT · Department of Fish and Wildlife Conservation

Objective Predatory invasive fishes may consume species of management interest and alter food webs. Blue Catfish Ictalurus furcatus is a large‐bodied, salinity‐tolerant species that exhibits broad diet breadth and preys on species of both conservation concern and fisheries management interest. To better understand the ecological consequences of the...

Ephemeral wetlands are globally important systems that are regulated by regular cycles of wetting and drying, which are primarily controlled by responses to relatively short-term weather events ( e.g. , precipitation and evapotranspiration). Climate change is predicted to have significant effects on many ephemeral wetland systems and the organisms...

With the expansion of human settlements and the environmental changes brought on by human activity and pollutants, toxicology and risk assessment of bird and reptile species is becoming increasingly of interest to toxicologists involved in environmental research. This book focuses specifically on environmental risk assessment in non-conventional bi...

Nonlinearity and spatial autocorrelation are common features observed in marine fish datasets but are often ignored or not considered simultaneously in modeling. Both features are often present within ecological data obtained across extensive spatial and temporal domains. A case study and a simulation were conducted to evaluate the necessity of con...

Stock assessment modeling provides a means to estimate the population dynamics of invasive fishes and may do so despite data limitations. Blue catfish (Ictalurus furcatus) were introduced to the Chesapeake Bay watershed to support recreational fisheries but also consume species of conservation need and economic importance. To assess management trad...

Bycatch in fisheries is a major threat to many seabird species. Understanding and predicting spatiotemporal changes in seabird bycatch from fisheries might be the key to mitigation. Inter-annual spatiotemporal patterns are evident in seabird bycatch of the U.S. Atlantic pelagic longline fishery monitored by the National Marine Fisheries Service Pel...

American Shad (Alosa sapidissima), Hickory Shad (A. mediocris), and river herrings (Alewife A. pseudoharengus and Blueback Herring A. aestivalis) are anadromous pelagic fishes, which as adults spend most of the annual cycle at sea, but enter the coastal rivers in spring to spawn. Once as one of the most valuable fisheries along the Atlantic coast,...

Tagging studies have been widely conducted to investigate the movement pattern of wild fish populations. In this study, we present a set of length-based, age-structured Bayesian hierarchical models to explore variabilities and uncertainties in modeling tag-recovery data. These models fully incorporate uncertainties in age classifications of tagged...

Individual growth rates are intrinsically related to survival and lifetime reproductive success and hence, are key determinants of population growth. Efforts to quantify age-size relationships are hampered by difficulties in aging individuals in wild populations. In addition, species with complex life-histories often show distinct shifts in growth...

Biological invasions occur as a multi-stage process and life history traits can change during the invasion process. Blue Catfish Ictalurus furcatus were introduced in three Virginia tidal tributaries of the Chesapeake Bay in the 1970s and 1980s, but have expanded their range to almost all large tributaries of the Bay. Understanding the species’ gro...

Spatial autocorrelation is common in environmental factors, species distributions, and predator-prey interactions. Spatially autocorrelated distribution of prey and strong prey selectivity by predators may cause spatial autocorrelation of the fish diet shown as higher similarity among diets of fish caught nearby or in the same trip. We explore the...

The incidental mortality of seabirds in fisheries ranks as the greatest threat impacting seabirds globally. However, its impact on seabird populations may have been substantially underestimated due to lost, undetected bycatch. To estimate the full extent of the bycatch problem, knowledge about the magnitude and the variability of the lost bycatch i...

Sexual and spatio-temporal variations have been observed in the life history parameters of many aquatic species and their causes have been related to harvesting pressure and environmental changes. This study aims to explore sexual, spatial and temporal variation in the growth and maturity through weight-at-length, length-at-age, and maturity-at-len...

As one of the top four commercially important species in China, yellow croaker (Larimichthys polyactis) with two geographic subpopulations, has undergone profound changes during the last several decades. It is widely comprehended that understanding its population dynamics is critically important for sustainable management of this valuable fishery i...

In temperate waters, growth and mortality of bony fishes is frequently estimated from age information derived from examination of annular rings on hard structures (e.g., otoliths). However, determining ages from hard structures can be time consuming, often requires sacrificing fish, and has associated costs for supplies and time of personnel proces...

Seabirds are facing increasing threats in both marine and terrestrial habitats, and many populations have experienced dramatic declines over past decades. Fisheries bycatch is the most pervasive at-sea threat and is of increasing concern in fisheries management and marine conservation. We predicted spatial and temporal heterogeneities of seabird by...

Whitespotted conger (Conger myriaster) is a marine migratory species with important economic and ecological values in Northwestern Pacific. The population status and distribution of whitespotted conger may have changed in the eastern coastal water of China owing to the intensive fishing pressure and human activities in the past few decades. There h...

The excess one pattern in count data has been documented in ecology but it has not been explicitly modeled or examined. In this study, we introduce a k-aggregated transformation of discrete distributions to better model count data with excess ones in a Bayesian generalized linear model framework and demonstrate its use with two groups of case studi...

Not much is known about the fleet level total seabird bycatch from pelagic longlines of United States vessels in the western North Atlantic or other fleets of the Atlantic or other oceans. Onboard observers generally only record seabird bycatch during line hauling. Seabirds are predominantly caught during the line setting stage, and, due to predati...

Background: Global regression models under an implicit assumption of spatial stationarity were commonly applied to estimate the environmental effects on aquatic species distribution. However, the relationships between species distribution and environmental variables may change among spatial locations, especially at large spatial scales with compli...

Background: Global regression models under an implicit assumption of spatial stationarity were commonly applied to estimate the environmental effects on aquatic species distribution. However, the relationships between species distribution and environmental variables may change among spatial locations, especially at large spatial scales with complic...

Background: Global regression models under an implicit assumption of spatial stationarity were commonly applied to estimate the environmental effects on aquatic species distribution. However, the relationships between species distribution and environmental variables may change among spatial locations, especially at large spatial scales with complic...

The seasonality of water levels in large river‐floodplain ecosystems, known as flood pulses, influence the dynamics of fish populations and associated catches. Various flood pulse variables (e.g. maximum stage) have been correlated to catches of river‐floodplain fishes, but no study to date has assessed the effects of various flood pulse variables...

Annual predictions of seabird bycatch in the U.S. Atlantic pelagic longline fishery were updated up to 2017 based on observer and logbook data. From 1992 to 2017, the NMFS Pelagic Observer Program (POP) documented 19,811 longline set operations, with 165 seabirds captured in 92 sets. The overall nominal bycatch rate was 0.0083 seabirds per set and...

One prerequisite for sustainable fisheries management is to match management actions with biological processes. Stocks are fundamental units for fisheries management. Understanding the spatial structure of fish stocks is critical for conducting defensible stock assessments, applying efficient management strategies, and ensuring the sustainability o...

In the 1970s and 1980s, blue catfish (Ictalurus furcatus) were introduced to the tidal rivers of Virginia. High abundances and uncertainty about population characteristics of blue catfish generated concern for economically important and imperiled species. We estimated natural mortality and size structure for four tidal river systems (i.e. James, Ma...

Exploring species-environment relationships to identify essential habitat areas is recognized as an effective way for resource conservation and management. Because of ecological and economic importance of Yellow Perch (Perca flavescens) in Lake Erie, it is essential to develop appropriate habitat models to analyze habitat supply of this species. Em...

Blue Catfish Ictalurus furcatus were introduced in the James, and Rappahannock Rivers over forty years ago and in the York drainage thirty years ago. Blue Catfish have since expanded into all major Virginia and many Maryland tributaries of the Chesapeake Bay. In August 2011, the Atlantic States Marine Fisheries Commission (ASMFC) approved a Resolut...

Understanding the spatial and temporal variability in life-history traits among populations is essential for the management of recreational fisheries. However, valuable freshwater recreational fish species often suffer from a lack of catch information. In this study, we demonstrated the use of an approach to estimate the spatial and temporal variab...

In this study, length-weight relationships and relative condition factors were analyzed for Yellow Croaker (Larimichthys polyactis) along the north coast of China. Data covered six regions from north to south: Yellow River Estuary, Coastal Waters of Northern Shandong, Jiaozhou Bay, Coastal Waters of Qingdao, Haizhou Bay, and South Yellow Sea. In to...

Yield of Yellow Croaker in China. Data were derived from China Fishery Statistical Yearbook from 1956 to 2012. (TIF)

Parameters a and b distributions among regions and years. A and B plots were parameters variation among regions, with C and D plots among years. B and D plots zoom the main parts with high frequency. (TIF)

Length frequency of Yellow Croaker. (TIF)

Monthly sample size of Yellow Croaker among regions and years. The detailed information of regions presents in Table 1; no individuals were caught during February, March and April. (DOCX)

Condition factors of Yellow Croaker relative to reference year of 1960, 1986 and 2007, and the references LWR models. See the text for the definition of Kcur/1960, Kcur/1960 and Kcur/2007. (DOCX)

LWR differences of Yellow Croaker among regions and years from the LMEM (R&Y.I&S). a, b, and c were plots among regions; d, e, and f were plots among years. a and d plots cover the whole range of length; b and e plots cover the median part (Length = 12–16 cm); c and f plots cover the large size (Length = 16–22 cm). (TIF)

Distribution of condition factors relative to reference years of 1960 (A), 1986 (B), 2005(C), 2007 (D), 2008~2009(E) and 2010(F). (TIF)

Understanding and monitoring life history traits is often important in endangered species conservation. Populations of the endangered mussel Cumberlandian combshell Epio - blasma brevidens have continued to decline in the Powell River, USA. Understanding and modeling mussel growth is critical for effective reintroduction of this endangered species....

Inferring growth for aquatic species is dependent upon accurate descriptions of age-length relationships, which may be degraded by measurement error in observed ages. Ageing error arises from biased and/or imprecise age determinations as a consequence of misinterpretation by readers or inability of ageing structures to accurately reflect true age....

Geographically weighted regression (GWR) is a relatively new technique to explore spatially-varying relationships between biological and environmental processes. It allows parameters to vary over space and assumes data to follow a normal distribution. We extend GWR to a geographically weighted generalized linear model (GW-GLM) by incorporating stat...

With the observer data from the National Marine Fisheries Service Pelagic Observer Programme (POP) and the logbook data from the US Atlantic pelagic longline fishery, we estimated the seabird bycatch in the fishery during 1992–2012. The POP observed 13 847 longline sets, with a total of 141 seabirds captured on 74 sets. The overall nominal catch ra...

Annual estimates of seabird bycatch in the U.S. Atlantic pelagic longline fishery were updated up to 2014. From 1992 to 2014, the NMFS Pelagic Observer Program (POP) documented 16,581 longline set operations, with 145 seabirds captured in 78 sets. The overall nominal bycatch rate was 0.0087 seabirds per set and 0.0121 birds per one thousand hooks....

In many marine fisheries assessments, population abundance indices from surveys collected by different states and agencies do not always agree with each other. This phenomenon is often due to the spatial synchrony/asynchrony. Those indices that are asynchronous may result in discrepancies in the assessment of temporal trends. In addition, commonly...

The hydroperiod of ephemeral wetlands is often the most important characteristic determining amphibian breeding success, especially for species with long development times. In mesic and wet pine flatwoods of the southeastern United States, ephemeral wetlands were a common landscape feature. Reticulated flatwoods salamanders (Ambystoma bishopi), a f...

Area and maximum depth (2005–2014) of 17 pine flatwoods wetlands. (XLSX)

Water depth measurements from 17 pine flatwoods wetlands over a 9-year period. (XLSX)

Global regression techniques that assume spatial stationarity are usually used to study the interaction between aquatic species distribution and habitat variables. In the present study, a local regression model, named geographically weighted regression (GWR), was used to question the spatial stationarity assumption in exploring the relationships be...

Information about Grass Carp Ctenopharyngodon idella survival would be useful for improving the management of fish used for aquatic weed control. Reliable methods for estimating annual poststocking survival of Grass Carp from radiotelemetry data do not exist because the fish remain sedentary for prolonged periods between movements, giving the false...

The association of species distribution and environmental variables is often complex, with nonlinear and interacting effects. Bayesian hierarchical models can quantify linear and high order effects of the variables, as well as their interaction effects. Their strength is to take into account the uncertainties in observation, models, and parameters....

The association of species distribution and environmental variables is often complex, with nonlinear and interacting effects. Bayesian hierarchical models can quantify linear and high order effects of the variables, as well as their interaction effects. Their strength is to take into account the uncertainties in observation, models, and parameters....

The federally endangered Cumberlandian combshell (Epioblasma brevidens) was propagated and reared to taggable size (5–10 mm), and released to the Powell River, Tennessee, to augment a relict population. Methodology using passive integrated transponder (PIT) tags on these mussels greatly facilitated the detection process. The overall mean detection...

A series of alternative state-space surplus production models were used to estimate biological reference points, i.e., FMSY and BMSY, and their uncertainty, for the Lake Nipigon lake whitefish fishery. We estimated the historic and current status of this fishery and found that both the reference point estimates and stock status were highly uncertai...

Long term nonstationary population dynamics are rarely applied in reality. The reasons include both the difficulty in solving the nonstationary models and the presence of the missing historical data. Atlantic weakfish (Cynoscion regalis) is one of the important fisheries along Atlantic coast. As for many fisheries, stationary models have been used...

The effects of algal density, water flow and substrate type on the survival and growth of newly metamorphosed juveniles of the rainbow mussel (Villosa iris) were investigated in 40 l recirculating culture systems. A split-plot design with a whole plot factor combining algal density and water flow, and a split-plot factor of substrate were applied i...

Incorporation of spatial dependence in bycatch modeling has been challenging because the bycatch data usually contain high percentage of zero observations and involve large dataset that may require intensive computing. The eigenfunction-based spatial filtering provides a flexible tool that allows the existing bycatch modeling approaches such as the...

a b s t r a c t Generalized linear models (GLMs) and generalized additive models (GAMs) are commonly used to stan-dardize catch rates as relative abundance indices in fisheries stock assessments. Spatial interpolation (SI) is an alternative way to estimate relative abundance indices but there have been no comparisons of the effectiveness of the two...

In weed control plans that use Grass Carp Ctenopharyngodon idella for intermediate control of hydrilla Hydrilla verticillata, the knowledge of population dynamics improves efficacy of management. Our objective was to characterize growth, mortality, and associated population metrics of long-lived (up to 16 years) triploid Grass Carp that were increm...

Natural resource modeling of fisheries is called stock assessment and is crucial for proper fisheries management. This paper reviews the commonly used models, the data needed, and the parameter estimation methods for these models in fisheries stock assessment. Fisheries management strategy evaluation and decision analysis, which are based on the mo...

Jiao, Y., Smith, E. P., O'Reilly, R., and Orth, D. J. 2012. Modelling non-stationary natural mortality in catch-at-age models. – ICES Journal of Marine Science, 69: 105–118. Non-stationarity in the natural mortality of many species has been discussed among research scientists, but no generally applicable models/methods have been developed where a s...

Many shark populations have significantly declined globally in the last few decades. Reasons that led to this alarming situation have been considered to be the slow intrinsic rates of increases of the shark populations and overexploitation from the directed-shark fishery and bycatch. Studies that can help to understand the fishery status and the in...

The oyster mussel (Epioblasma Capsaeformis) has declined 80% during the last several decades and is now listed as a federally endangered freshwater bivalve of United States. The restoration of the oyster mussel population is urgently needed. However, some vital rates, such as mortality rates, fertility rate and recruitment rate, are still poorly un...

A method for estimating time-based instantaneous total mortality rate (Z) from multiple cohort catch per unit effort (CPUE) data was developed. The Zs in different n continuous years, which were assumed constant in each n year, were estimated using the age-based CPUE data within these years. Our simulation study found that the trends of the estimat...

Recent studies suggest that use of circle hooks can reduce the incidental mortality of some marine fishes and sea turtles in longline fisheries. Analysis of data from the US National Marine Fisheries Service Pelagic Observer Program (POP) revealed a significant hook effect on seabird bycatch. Our analysis focused on the three areas with highest sea...

We compared the performance of two traditional sampling designs with three adaptive sampling designs using simulated data based on fishery-independent surveys for yellow perch in Lake Erie. Traditionally, the fishery-independent survey has been conducted with a stratified random sampling design based on basin and depth strata; however, adaptive sam...

Natural resource modeling of fisheries is called stock assessment and is crucial for proper fisheries management. This paper reviews the commonly used models, the data needed, and the parameter estimation methods for these models in fisheries stock assessment. Fisheries management strategy evaluation and decision analysis, which are based on the mo...

Japanese Medaka, Oryzias latipes, is a widely used organism in biological investigations because of its high fecundity, small adult size, and ease of husbandry. However, many aspects of its life history have not been fully described. In this study we determine patterns of somatic growth, frequency of egg production, and competency of eggs. We also...