Capture Location Research Articles

A Modelling Strategy to Estimate Conditional Probabilities of African Origins: The Collapse of the Oyo Empire and The Transatlantic Slave Trade, 1817–1836

Abstract Intra-African conflicts during the collapse of the kingdom of Oyo from 1817 to 1836 resulted in the enslavement of an estimated 121,000 people who were then transported to coastal ports via complex trade networks and loaded onto slave ships destined for the Americas. Historians have a good record of where these people went across the Atlantic, but little is known about where individuals were from or enslaved within Africa. In this work, we develop a novel statistical modelling strategy to describe the enslavement of people given documented violent conflict, the transport of enslaved peoples from their location of capture to their port of departure, and—given an enslaved individual's location of departure—that person's probability of origin. We combine spatial prediction of conflict density via kriging with a Markov decision process characterising intra-African transportation. The results of this model can be visualised using an interactive web application to plot—for the first time—estimated conditional probabilities of historical origins during the African diaspora. Understanding the likely origins within Africa of enslaved people may have ramifications for the history of the Atlantic world, whereby the ocean connects, rather than disconnects, Africa, the Americas, and Europe.

Influence of life history variation and habitat on mercury bioaccumulation in a high-order predatory fish in tropical Australia

Mercury distribution and bioaccumulation in aquatic ecosystems of tropical Australia is poorly characterised. Barramundi (Lates calcarifer), a widespread high-order predator in both fresh and coastal marine waters of the region, fulfils requirements for a bio-indicator of mercury contamination. In a study of the Mary River system of the Northern Territory, total mercury in the muscle tissue of 300 specimens gathered over four years (2013–2017, across both wet and dry seasons) was determined by direct combustion–atomic absorption spectrometry. Source of nutrition and trophic position of barramundi in the food web was also estimated via carbon and nitrogen isotopes (δ13C and δ15N), respectively, in tissue by stable isotope mass spectrometry, and determination of strontium isotopes (87Sr/86Sr) in otoliths by laser ablation–ICPMS differentiated between freshwater and saltwater residence. Results showed that fish moving into freshwater floodplain wetlands concentrated mercury in muscle tissue at approximately twice the level of those that remained in saline habitats. Resolving life histories through otolith analyses demonstrated diversity in mercury bioaccumulation for individual fish of the same migratory contingent on the floodplains. Although trophic level (δ15N), capture location, source of nutrition (δ13C), and age or size partly predicted mercury concentrations in barramundi, our results suggest that individual variability in diets, migration patterns and potentially metabolism are also influential. Using a migratory fish as a bio-indicator, and tracking its life history and use of resources, proved valuable as a tool to discern hot spots in a coastal waterway for a contaminant, such as mercury.

A gazelle's extraordinary, 18,000-km-long journey through the steppes of Mongolia.

A gazelle's extraordinary, 18,000-km-long journey through the steppes of Mongolia.

Voluntary fishing logbooks are essential for unveiling unsustainable bycatch levels and appropriate mitigating measures: The case of sea turtles in the Gulf of Manfredonia, Adriatic Sea

Abstract Studying the impact of bycatch on marine megafauna, including sea turtles, is challenging for a variety of technical and biological reasons. The Mediterranean Sea has among the highest levels of turtle bycatch globally, notably of the loggerhead sea turtle (Caretta caretta), and bottom trawling represents a particularly relevant threat. Bottom trawlers from a recently discovered neritic foraging area, the Gulf of Manfredonia, reported 1,152 loggerhead turtles incidentally caught in the period 2015–2020. Capture locations were available for 497 turtles. These data were complemented by the distribution of fishing effort obtained by the vessel monitoring system. High bycatch rates were observed, leading to more than an estimated 5,600 annual captures and to the death of a minimum of 560 large individuals with high reproductive value. These findings are extremely concerning for the affected population and require immediate action. A strong seasonality of turtle bycatch was observed, with most captures occurring in November–March when fishing effort occurs in shallow waters where turtles concentrate all year round. Therefore, a seasonal approach (e.g. adopting measures only in the high‐turtle bycatch season) can be pursued as long as the spatial distribution of fishing effort varies among seasons. However, such a spatio‐temporal pattern should be monitored; then, in the case of change, although more difficult to implement, an area‐based conservation approach should be pursued. Several recommendations are provided, including the urgent implementation of turtle excluder devices, at least on a seasonal basis. This case shows that identifying the best conservation approaches requires information on the actual spatio‐temporal pattern of turtle occurrence and bycatch. Such information can only be derived from spatial distribution of bycatch and fishing effort obtained through a voluntary collaboration of fishers.

A Comparison of Different Tournament Weigh‐In Formats on the Short‐Term Postrelease Behavior of Black Bass Assessed with Biologgers

AbstractBlack bass Micropterus spp. live‐release tournaments are a popular activity in North America. Efforts continue to further increase survival and enhance welfare of fish released from competitive angling events. Recently, some tournaments have adopted a new weigh‐in format in which black bass are weighed immediately (hanging from a scale in air) and released at the capture location. More conventional tournaments involve retaining black bass in a live well and delivering them to a central location to be weighed (wet or dry weigh‐in). We used biologgers that measured swimming activity, depth selection, and water temperature selection to examine how different weigh‐in formats alter postrelease behavior of Smallmouth Bass M. dolomieu and Largemouth Bass M. salmoides. All fish showed a significant decrease in swimming activity as time progressed during the 10‐min monitoring period, regardless of the weigh‐in format. Swimming activity remained elevated (i.e., hyperactivity) for a longer period of time for black bass that were retained in live wells compared to those that were subjected to the catch, weigh, and release weigh‐in format and the control (fish that were caught and immediately released without air exposure). Swimming activity of black bass tended to decrease as they achieved greater depths with cooler water temperatures. For both species, the water temperature selected postrelease was influenced by the weigh‐in format. Black bass that were dry weighed and wet weighed spent more time in warmer water temperatures than fish in the control group or fish that were caught, weighed, and released. This study suggests that to reduce behavioral alterations associated with wet or dry weigh‐ins, tournament organizations need to carefully select the weigh‐in location, allowing easy access to refuge (i.e., habitat complexity similar to that of the capture location) having the cooler water temperatures commonly associated with deeper water. These results also suggest that catch, weigh, and release formats could be beneficial for black bass during periods of the year with elevated water temperature.

Mercury and Radiocesium Accumulation and Associations With Sublethal Endpoints in the Florida Green Watersnake (Nerodia floridana).

Mercury (Hg) and radiocesium (137 Cs) are well-known environmental contaminants with the potential to impact the health of humans and wildlife. Snakes have several characteristics conducive to studying environmental contamination but have rarely been included in the monitoring of polluted sites. We investigated the bioaccumulation of Hg and 137 Cs and associations with sublethal effects (standard metabolic rate [SMR] and hemoparasite infections) in Florida green watersnakes (Nerodia floridana). We captured 78 snakes from three former nuclear cooling reservoirs on the US Department of Energy's Savannah River Site in South Carolina (USA). For captured snakes, we (1) determined whole-body 137 Cs, (2) quantified total Hg (THg) using snake tail clips, (3) conducted hemoparasite counts, and (4) measured the SMR. We used multiple regression models to determine associations among snake body size, capture location, sex, tail THg, whole-body 137 Cs, Hepatozoon spp. prevalence and parasitemia, and SMR. Average whole-body 137 Cs (0.23 ± 0.08 Becquerels [Bq]/g; range: 0.00-1.02 Bq/g) was correlated with snake body size and differed significantly by capture site (Pond B: 0.67 ± 0.05 Bq/g; Par Pond: 0.10 ± 0.02 Bq/g; Pond 2: 0.03 ± 0.02 Bq/g). Tail THg (0.33 ± 0.03 mg/kg dry wt; range: 0.16-2.10 mg/kg) was significantly correlated with snake body size but did not differ by capture site. We found no clear relationship between SMR and contaminant burdens. However, models indicated that the prevalence of Hepatozoon spp. in snakes was inversely related to increasing whole-body 137 Cs burdens. Our results indicate the bioaccumulation of Hg and 137 Cs in N. floridana and further demonstrate the utility of aquatic snakes as bioindicators. Our results also suggest a decrease in Hepatozoon spp. prevalence related to increased burdens of 137 Cs. Although the results are intriguing, further research is needed to understand the dynamics between 137 Cs and Hepatozoon spp. infections in semiaquatic snakes. Environ Toxicol Chem 2022;41:758-770. © 2022 SETAC.

A quantitative approach to investigate natal philopatry in Hickory Shad (Alosa mediocris) using otolith chemistry

The goal of this study was to understand if Hickory Shad exhibit natal homing. Hickory Shad were captured in eighteen major rivers along the known spawning range. LA-ICP-MS was used to quantify seven elements (Mg, Mn, Cu, Zn, Sr, Ba, and Pb), along a continuous transect that ran from the ventral edge of the otolith through the core to the dorsal edge of each otolith, resulting in a time resolved model of the environmental exposure history of each fish. Hidden Markov models were used to estimate a natal river element signature for each Hickory Shad. The true number of natal rivers present in the dataset were unknown, so a Gaussian mixture model was used to estimate the number of mixture distributions and classify hickory shad based on natal river signatures. Five clusters were identified; Hickory Shad captured in the majority of rivers were assigned to one of three or more clusters, while those captured in a few rivers had unique element profiles and were assigned the same cluster at high rates (70%–90% of samples per river). A Chi-Square test confirmed that there was a significant relationship (p < 0.01) between capture location and cluster assignment. Overall, the results of this study suggest a high rate of straying from natal rivers through most of the Hickory Shad spawning range, and that some localized populations may return to natal rivers at a higher rate. This study provides the first piece of quantitative information about the rate at which Hickory Shad exhibit natal homing, and provides an important inferential baseline for future studies to understand their life history strategies and population dynamics.

Coordinated planning of fast charging station and distribution network based on an improved flow capture location model

Coordinated planning of fast charging station and distribution network based on an improved flow capture location model

Modeling the Habitat Distribution of Acanthopagrus schlegelii in the Coastal Waters of the Eastern Taiwan Strait Using MAXENT with Fishery and Remote Sensing Data

Black sea bream, Acanthopagrus schlegelii, is among the most commercially valuable species in the coastal fishery industry and marine ecosystems. Catch data comprising capture locations for the gillnet fisheries, remotely sensed environmental data (i.e., sea surface temperature, chlorophyll-a concentration, and current velocity), and topography (bathymetry) from 2015 to 2018 were used to construct a spatial habitat distribution of black sea bream. This species is concentrated in coastal waters (&lt;3 nm) from December to April (spawning season). The maximum entropy (MaxEnt) method and corresponding habitat suitability index among seasons were used to clarify the species’ spatial distribution and identify the seasonal variations in habitat selection. The patterns corresponded closely to the changes in oceanographic conditions, and the species exhibited synchronous trends with the marine environment’s seasonal dynamics. Chlorophyll-a concentration and bathymetry substantially influenced (80.1–92.9%) black sea bream’s habitat selection. By applying the MaxEnt model, the optimal habitats were identified with four variables including depth and satellite-derived temperature, current velocity and chlorophyll-a concentration, which provides a foundation for the scientific assessment and management of black sea bream in coastal waters of the Eastern Taiwan Strait.

Results of the collaborative Lake Ontario bloater restoration stocking and assessment, 2012–2020

Bloater, Coregonus hoyi, are deepwater planktivores native to the Laurentian Great Lakes and Lake Nipigon. Interpretations of commercial fishery time series suggest they were common in Lake Ontario through the early 1900s but by the 1950s were no longer captured by commercial fishers. Annual bottom trawl surveys that began in 1978 and sampled extensively across putative bloater habitat only yielded one individual (1983), suggesting that the species had been locally extirpated. In 2012, a multiagency restoration program stocked bloater into Lake Ontario from gametes collected in Lake Michigan. From 2012 to 2020, 1,028,191 bloater were stocked into Lake Ontario. Bottom trawl surveys first detected stocked fish in 2015, and through 2020 ten bloater have been caught (total length mean = 129 mm, s.d. = 44 mm, range: 96–240 mm). Hatchery applied marks and genetic analyses confirmed the species identification and identified stocking location for some individuals. Trawl capture locations and acoustic telemetry suggested that stocked fish dispersed throughout the main lake within months or sooner, and the depth distribution of recaptured bloater was similar to historic distributions in Lake Ontario and other Great Lakes. Predicted bloater trawl catches, based on modeled population abundance and trawl survey efficiency, were similar to observed catches, suggesting that post-stocking survival is less than 20% and contemporary bottom trawl surveys can quantify bloater abundance at low densities and track restoration.

Assessing the migratory histories, trophic positions, and conditions of lake sturgeon in the St. Croix and Mississippi Rivers using fin ray microchemistry, stable isotopes, and fatty acid profiles

BackgroundReproducing populations of invasive carps (Hypophthalmichthys spp.) could alter aquatic food webs and negatively affect native fishes in the Mississippi National River and Recreation Area (MISS) and the St. Croix National Scenic Riverway (SACN). However, proposed invasive carp barriers may also threaten populations of native migratory fishes by preventing movements of fish between rivers that are necessary for life history requirements. In this study, nonlethal chemical techniques were used to provide baseline data related to the condition, trophic position, and migratory histories of lake sturgeon (Acipenser fulvescens) captured in the Mississippi and St. Croix Rivers.ResultsFish length and weight measurements and age estimates determined from pectoral fin rays demonstrated that lake sturgeon from the Mississippi River had greater lengths-at-age compared to sturgeon from the St. Croix River. However, length–weight relations were similar for sturgeon from the Mississippi and St. Croix Rivers. Lake sturgeon captured from different locations had distinguishable fatty acid signatures, and stable isotope analyses demonstrated that lake sturgeon from the Mississippi River generally feed at a higher trophic level than those in the St. Croix River. Strontium-to-calcium ratios (Sr:Ca) from fin ray cross sections indicated that sturgeon captured from the Mississippi River had higher Sr:Ca values than sturgeon captured from the St. Croix River, and natal origins and capture locations were not significantly different among sturgeon captured within individual rivers. Most sturgeon were captured in water with a similar Sr:Ca signature as their natal waters, indicating that there is some separation between populations of lake sturgeon in the St. Croix and Mississippi Rivers. However, Sr:Ca data indicated substantial variation in movement patterns among individual lake sturgeon, indicating that populations interact through migrations of individual fish between rivers.ConclusionsStudy results provide baseline condition and food web structure index data for assessing changes in lake sturgeon populations should invasive carps become established in these areas of the Mississippi and St. Croix Rivers. Controlled-exposure and telemetry studies would help verify and enhance the relations between Sr:Ca signatures in water and lake sturgeon pectoral fin rays to further assess mixing of sturgeons between rivers.

Genetic characteristics of yellow seabream Acanthopagrus latus (Houttuyn, 1782) (Teleostei: Sparidae) after stock enhancement in southeastern China coastal waters

Yellowfin seabream is an important economic fish that is widely distributed in the East and South China seas. Many attempts to enhance stocks of yellowfin seabream have occurred in China, but a lack of genetic information for this species after stock release represents an obstacle to its management and conservation. To provide scientific guidance for sustainable germplasm resource development, we sequence the mitochondrial DNA (mtDNA) control region (CR) of 123 yellowfin seabream from 6 sample populations (Xiamen, Dongshan I, Dongshan II, Yangjiang, Fangchenggang, and Beibu Gulf). Populations of both wild and cultured yellowfin seabream have high genetic diversity, which we relate to their breeding habits and growth rate. A neighbor-joining tree of CR haplotypes reveals no specific phylogenetic structure corresponding to location of fish capture. Both neutral test and nucleotide mismatch distribution analyses suggest that yellowfin seabream have experienced population expansion events. Pleistocene glacial periods and recent stock releases have played important roles in the formation of present-day phylogeographical patterns. Our study provides baseline information which will assist future research on genetic structure, genetic diversity, and historical demography of yellowfin seabream after stock release in southeast China coastal waters. The use of exotic seeds should be avoided in stock breeding and release, and relevant follow-up surveys and genetic monitoring should be undertaken to clarify the genetic impact of exotic seed use on wild populations.

Strategic Carbon Dioxide Infrastructure to Achieve a Low-Carbon Power Sector in the Midwestern and South-Central United States

Large-scale carbon capture, utilization, and storage (CCUS) requires development of critical infrastructure to connect capture locations to geological storage sites. Here, we investigate what government policies would be required to make the development of CO2 pipelines and large-scale CCUS in the power sector economically viable. We focus on the transition from conventional coal to non-CO2-emitting natural gas-fired Allam-cycle power with CCUS and study a system in which 156 Allam-cycle power generators representing 100 GW of capacity send their captured CO2 emissions to three geological storage locations in the central United States through 7500 miles of new pipeline. Enabling policies for this system include low-interest government loans of approximately $20 billion for pipeline construction and an extended 20-year Section 45Q tax credit, or similar longer-term carbon price incentive. Additional policy support will be needed to enable initial construction of pipelines and early-mover power generators, such as cost-sharing, governments assuming future demand risk, or increased subsidies to early movers. The proposed system will provide reliable, dispatchable, flexible zero-emission power generation, complementing the intermittent generation by renewables in a decarbonized U.S. power sector. The proposed pipeline network could also connect into future regional infrastructure networks and facilitate large-scale carbon management.

Evaluation of the Humphead Wrasse, Cheilinus undulatus, in Shallow Water Habitats in Saipan Lagoon, Commonwealth of the Northern Mariana Islands1

Visual census surveys utilizing a distance sampling approach were undertaken in Saipan Lagoon to determine the density of humphead wrasse (HHW) in four shallow water habitats, and compared to observations in the Saipan nighttime commercial spear fishery. Fish observed from the survey ranged in total length from 6.5 to 35 cm total length, generally smaller than the range of fish sampled from the commercial fishery of 16 to 47 cm total length. The majority of survey observations occurred in the central and northern part of Saipan Lagoon, which correlated with capture locations documented in the commercial fishery landings. Analysis of contemporary and historical commercial fishery data showed that HHW could not be considered primary fishery target species. Distance sampling results indicated that coral/hard bottom and Enhalus acroroides seagrass were the habitats most important to HHW, as reflected by higher density estimates. The use of distance sampling was useful in estimating the spatial distribution and density of HHW, and should be considered when assessing other rare marine finfish species.

Pre and Post Sterilization Behaviour Studies of Rhesus macaque (Macaca mulatta) in Himachal Pradesh, India

Abstract: Rhesus Macaque (Macaca mulatta) population in India has been on a rise due to their high breeding rate and ability to acclimatize to various environments (Imam 2013). They are often seen in Human habitations especially in agricultural fields, raiding crops and becoming a nuisance to the farmers. According to agricultural department, the marauding macaques have raided agricultural crops worth Rs 185 crore and horticulture crops worth Rs 38 crore in various districts of HP in 2014. To address this menace, sterilization programme is carried out at respective Monkey sterilization centre (MSC’s) established at 8 monkey affected districts across Himachal Pradesh. This study aims to investigate and understand the various behavioural changes that may occur (intra specific, social , feeding, stress/aggression ) in the period of post sterilization of Rhesus macaque. The proposed study site for this project is a Village called Gopalpur located in Kangra District of Himachal Pradesh. For pre-sterilization monitoring, a virgin Troupe was identified and selected for capture based on the MSC’s record on capture locations and sterilized monkeys. The virgin troupe was monitored for their behaviour which included changes and their usual aggression, Feeding, grooming, sleeping, and mating and home range, for a period of 3 weeks. 100 % capture of this troupe was aimed for sterilization at a time. But failure of the same, the remaining population was to be monitored for their behavioural changes due to separation from their parent troupe. Capturing Rhesus of Chamunda Area near the addressed site was challenging due to many reasons which are discussed in the report. Three monkeys were caught successfully out of which two escaped and one turned out to be pregnant. The identified troupe couldn’t be captured and sterilized to study their post behavioural changes. The pregnant monkey was released back at the point of capture as it can’t be sterilized. This study on presterilization behaviour will form a baseline data for future studies on their post-sterilization behavioural changes. The study will also help in streamlining the monkey capturing process. Keywords: Rhesus macaque, Behaviour, Monkey sterilisation centre, MSC, Sterilisation program.

Spatial distribution of anti-Toxoplasma gondii antibody-positive wild boars in Gifu Prefecture, Japan

Toxoplasma gondii is a globally wide-spread parasite that infects almost all species of mammals and birds, including humans. We studied the spatial distribution of individual T. gondii-seropositive wild boar in Gifu Prefecture (10,621 km2), Japan. Altogether, 744 wild boars were captured at 663 points around human settlements in Gifu Prefecture. Serum samples were collected after recording the exact capture locations, along with each wild boar’s body length and sex. We then used a commercial enzyme-linked immunosorbent assay kit for swine to measure anti-T. gondii antibodies in these animals. Among the 744 wild boars, 169 tested positive for T. gondii (22.7%). No significant difference in T. gondii seroprevalence was observed between the mountainous northern region with high winter snow cover and the mild-wintered geographical plain of the southern part of the prefecture. In contrast, 8 of the 11 wild boars that were captured in a public park surrounded by residential areas showed T. gondii seropositivity (72.7%), a value significantly higher than those of the wild boar populations in the other prefecture areas. This in-depth analysis, which spans the big city suburbs and rural areas of a whole prefecture, explains the seroprevalence of zoonotic T. gondii in wild boar and has public health implications.

Temperature-Driven Growth Variation in a Deep-Sea Fish: The Case of Pagellus bogaraveo (Brünnich, 1768) in the Azores Archipelago

The deep ocean ecosystem hosts high biodiversity and plays a critical role for humans through the ecosystem services it provides, such as fisheries and climate regulation. However, high longevity, late reproduction, and low fecundity of many organisms living in the deep ocean make them particularly vulnerable to fishing and climate change. A better understanding of how exploitation and changing environmental conditions affect life-history parameters (e.g., growth) of commercially important fish species is crucial for their long-term sustainable management. To this end, we used otolith increment widths and a mixed-effects modeling approach to develop a 42-year growth chronology (1975–2016) of the commercially important deep-sea fish species blackspot seabream (Pagellus bogaraveo) among the three island groups of the Azores archipelago (Northeast Atlantic). Growth was related to intrinsic (age and age-at-capture) and extrinsic factors (capture location, temperature-at-depth, North Atlantic Oscillation (NAO), Eastern Atlantic Pattern (EAP), and proxy for exploitation (landings)). Over the four decades analyzed, annual growth patterns varied among the three island groups. Overall, temperature-at-depth was the best predictor of growth, with warmer water associated with slower growth, likely reflecting physiological conditions and food availability. Average population growth response to temperature was separated into among-individual variation and within-individual variation. The significant among-individual growth response to temperature was likely related to different individual-specific past experiences. Our results suggested that rising ocean temperature may have important repercussions on growth, and consequently on blackspot seabream fishery production. Identifying drivers of blackspot seabream growth variation can improve our understanding of past and present condition of the populations toward the sustainable management of the fishery.

Environmental exposure to cadmium reduces the primary antibody-mediated response of wood mice (Apodemus sylvaticus) from differentially polluted locations in the Netherlands

The Wood mouse (Apodemus sylvaticus) is a widespread mammalian species that acts as a reservoir host for multiple infections, including zoonotic diseases. Exposure to immunotoxins, like for instance trace metals, may reduce the ability of the host to mount proper responses to pathogens, potentially increasing the transmission and prevalence of infections. Antibody-mediated responses are crucial in preventing and limiting infections, and the quantification of the primary antibody response is considered a sensitive predictor of immunosuppression. The current study aims to investigate effects of cadmium exposure on the antibody-mediated responses of wood mice inhabiting polluted and non-polluted areas in the Netherlands. Wood mice were captured alive at different locations and immunized to sheep red blood cells (SRBC) to induce a primary antibody response. SRBC-specific antibody-producing cells, or plaque forming cells (PFC), were quantified and related to kidney cadmium levels. Differential circulating main leukocyte populations were also characterised. Cadmium concentrations in mice kidneys differed between mice captured at different locations, and increased with individual body mass, likely associated with age-related time of exposure. Effect of cadmium was apparent on the percentages of B cell counts in blood. Because of potential natural immune heterogeneity between wild rodent populations, mice immune responses were analysed and compared grouped by captured locations. Capture location had significant effect on the total counts of white blood cells. Increasing cadmium exposure in wood mice captured from polluted sites was associated with a decrease of splenic PFC counts. This field research shows that wood mice antibody responses can be impaired by cadmium exposure, even at low environmental levels, by affecting B cell functioning mainly. Impaired B cell function can make exposed mice more susceptible to infections, potentially increasing the reservoir function of their populations. It also shows that immunomodulatory effects in the field should be assessed site specifically.

Integrating telemetry data at several scales with spatial capture–recapture to improve density estimates

AbstractAccurate population estimates are essential for monitoring and managing wildlife populations. Mark–recapture sampling methods have regularly been used to estimate population parameters for rare and cryptic species, including the federally listed Mojave desert tortoise (Gopherus agassizii); however, the methods employed are often plagued by violations of statistical assumptions, which have the potential to bias density estimates. By incorporating spatial information into conventional density estimation models, spatial capture–recapture (SCR) models can account for common assumption violations such as spatially heterogeneous detection probabilities and temporary emigration when animals leave plots during a survey. We conducted mark–recapture surveys at 10 1‐km2 plots in and adjacent to the Ivanpah Valley of California and Nevada from 2015 to 2019. Locality data were collected concurrently using radio‐telemetry and GPS data loggers. GPS data demonstrated that desert tortoises frequently exhibited temporary emigration outside a plot during the survey periods, thereby complicating standard approaches for closed‐model density estimation. We integrated mark–recapture survey data for subadults and adults at each plot with corresponding spatial capture locations and supplementary spatial data using a modified SCR model fitted in a Bayesian framework. We compared density estimates modeled with conventional non‐spatial methods, as well as three SCR models based on symmetrical usage areas described by various levels and types of supplementary spatial data. The conventional model consistently resulted in inflated estimates of density while the SCR models allowed us to generate spatially corrected estimates for a species where detectability and densities are low. However, we found that if not properly specified, the temporal scale of supplementary data may result in an unintended source of bias in parameter estimates. Integrating spatial data over a larger temporal scale than mark–recapture surveys were conducted resulted in higher detection probabilities and lower density estimates, due to an overestimation of space use. Our results not only demonstrate the importance of accounting for spatial information but also the value of understanding the potential for bias when integrating multiple data sets at different temporal resolutions. The methods presented can be used to enhance monitoring efforts for the Mojave desert tortoise and other species where mark–recapture methods are used.

Identification of Micro-organisms (Parasites and Bacteria) which are Potential as Pathogenic Agent in Glass Eel of Anguilla spp. at the Eel Capture Location, Sukabumi, West Java

Eel (Anguilla sp.) is one of the important commercial fish in some countries particularly in East Asian countries such as Japan, South Korea, China, and Taiwan. The need of eel fry or frequently called as glass eel still relies on the natural capture. The issue of natural captured fish is the high level of bacterial infections and diseases. The dependence of glass eel from the nature provides an indication of infections of parasites and bacteria in glass eel. The existence of parasites and bacteria as microorganisms which are potential as pathogenic agents in the cycle of eel culture can be a serious obstacle, so that the glass eel handling needs a particular attention since the capturing proses from the nature. Therefore, identification of parasites and bacteria in the capture location of glass eel was necessarily conducted in Pelabuhan Ratu Bay, Sukabumi, West Java. The glass eel sampling was conducted in May-June 2019, in 3 locations of estuary with the highest capture yield namely Cimandiri River, Cikaso River and Cibuni River. The number of samples taken were 30 eels at each river location with 2 replicates, so that the total eel samples which were taken were 180 eels. Identification of parasites was conducted by examination of ectoparasite and endoparasite and dentification of bacteria was conducted by conventional method (biochemical method). Based on the result of identification, there was no parasite found in the glass eel samples, while bacteria found as many as 12 species and 3 dominant species namely Listeria sp. found in 40 eel samples with prevalence of 22.2%, Aeromonas hydrophila found in 28 eel samples with prevalence of 15.6%, and Staphylococcus spp. found in 22 eel samples with prevalence of 12.2%.Keyword : Micro-organism, Pathogen, Glass Eel, Anguilla spp.