Seine Hauls Research Articles

Using Bayesian multispecies models to evaluate fish and invertebrate detection probability and distribution in the hypersaline Bahia Grande tidal basin

AbstractObjectiveIn 2000, the Laguna Atascosa National Wildlife Refuge acquired the Bahia Grande (Texas) management unit, a space that had lain barren and arid for 70 years. A large cooperative partnership launched a restoration project to replenish the basin and recover its original tidal hydrology. In 2005, the construction of a pilot channel successfully restored water throughout the basin, and plans to eventually widen the channel were developed. Our study aims to evaluate an estuarine habitat restoration by assessing ecological drivers and the impacts on species diversity.MethodsWe evaluated species richness, detection/occupancy rates, and species–habitat relationships, and we estimated the sampling effort required to achieve a given level of relative precision if relative abundance was used instead of occupancy to inform future sampling. Sampling gear included bag seines for juvenile life stages and gill nets for capturing subadult and adult life stages. For analysis, we used a Bayesian negative binomial linear mixed‐effects model to evaluate richness–habitat relationships and a hierarchical Bayesian multispecies model to evaluate individual species–habitat relationships, and we calculated the total number of fish captured and relative standard error by gear and sample year to produce a precise estimate of relative abundance.ResultOverall, 29 species were caught between 2018 and 2021. Salinity emerged as a clear driver in the Bahia Grande, as both species richness and individual‐level responses were negatively associated with high salinity values. We found that catch estimated as relative abundance had much variability, as is typical of most survey programs assuming constant detectability, and the number of net sets or seine hauls required to achieve a given level of relative precision varied considerably depending on the species, season, year, and gear type. The most collected species were found in the upper extremes of their salinity tolerances—potentially a unique adaptation to this hypersaline system.ConclusionBaseline data suggest that for the channel widening to be successful, there must be a noticeable increase in suitable habitat characteristics throughout the basin.

Imperfect detection and misidentification affect inferences from data informing water operation decisions

AbstractObjectiveManagers can modify river flow regimes using fish monitoring data to minimize impacts from water management infrastructure. For example, operation of the gate‐controlled Delta Cross Channel (DCC) in California can negatively affect the endangered Sacramento River winter‐run Chinook Salmon Oncorhynchus tshawytscha. Although guidelines have been developed for DCC operations by using real‐time juvenile fish sampling count data, there is uncertainty about how environmental conditions influence fish occupancy and the extent to which those relationships are affected by sampling and identification error.MethodsWe evaluated the effect of environmental conditions, imperfect detection, and misidentification error on salmon occupancy by analyzing data using hierarchical multistate occupancy models. A total of 14,147 trawl tows and beach seine hauls were conducted on 1058 sampling days between October and December from 1996 to 2019. During these surveys, 2803 juvenile winter‐run Chinook Salmon were identified, and approximately 29% of the sampling days had at least one winter‐run juvenile detected.ResultThe probability of misidentifying an individual juvenile winter‐run Chinook Salmon in the field was estimated to be 0.056 based on fish identification examinations and genetic sampling. Occupancy varied considerably and was related to flow characteristics, water clarity, weather, time of year, and whether occupancy was detected during the previous sampling day. However, these relationships and their significance changed considerably when accounting for imperfect detection and the probability of misidentifying individual juvenile salmon. Detection was <0.3 under average sampling conditions during a single sample and was influenced by flow, water clarity, site, and volume sampled.ConclusionOur modeling results indicate that DCC gate closure decisions could occur on fewer days when imperfect detection and misidentification error are not accounted for. These findings demonstrate the need to account for identification and detection error while using monitoring data to assess factors influencing fish occupancy and inform future management decisions.

Effects of seining effort on estimates of fish diversity in a sand-bed river

Changes in species diversity can be an indicator of ecosystem disturbance, impairment, or recovery. Estimating sampling effort needed to adequately represent stream fish assemblages is necessary for informing conservation actions. Increased sampling intensity can increase species detection, affecting the accuracy and precision of biodiversity indices. Seining is commonly used in fish surveys in sand-bottomed streams of the western USA. Here, we sampled 20, 200-m long stream sites each with 40 consecutive seine hauls to determine how increased within-site effort affected measures of species diversity. An average of 10 seine hauls were required to collect 75% of species present at sites in 40 seine hauls, while 18 seine hauls were required to collect 100% of species observed at a site sampled with 40 hauls. Simpson’s diversity index was highly variable when fewer than 7 seine hauls were performed at each site but stabilized when effort was > 15 seine hauls per site. Total dissimilarity and β-diversity components were variable under low sampling effort and also stabilized when effort reached 15 seine hauls per site. However, sampling with more than 18–20 seine hauls per site yielded few additional species. In shallow, sand-bed streams, we suggest sampling with < 5 seine hauls per 200 m of stream can result in unreliable estimates of α-diversity and variation in β-diversity. Increased effort of 15–20 seine hauls per 200 m of stream captured nearly all species present in 40 hauls per 200 m and stabilized species evenness and β-diversity indices.

Rediscovery of the Spiny-cheek crayfish (Faxonius limosus) in the Middle and Upper Susquehanna River Basin in Pennsylvania.

The first state-wide survey of crayfishes in Pennsylvania was completed in 1905 by Dr. Ortmann of the Carnegie Museum of Natural History. One species, the Spiny-cheek crayfish (Faxonius limosus), was determined to be endemic to the Delaware, Susquehanna, and Potomac River Basins of Pennsylvania. Since the Ortmann survey in 1905, additional surveys have returned with other species. Due to landscape alteration (urbanization and agriculture) and the presence of invasive crayfish, the current distribution and conservation status of F. limosus is unknown. We have completed surveys at both historic records and new sites through the upper portion of the Susquehanna River Basin. Each site was standardized with a sampling effort of ten seine hauls distributed to target all available habitats. All crayfish collected were identified to species and curated into the West Liberty University Astacology Collection. A qualitative habitat evaluation index score (QHEI) was generated at every site and water quality data was collected using a YSI Pro 1030 data sonde. Thus far, 312 sites have been surveyed. Unexpectedly, we did find F. limosus in the Lackawanna River, a tributary of the upper Susquehanna River. All other historic sites returned either invasive F. rusticus or native F. obscurus. The absence of F. limosus at historic locations indicates a decline in range, which likely warrants state-level protection for this species.

Sciaenid courtship sounds correlate with juvenile appearance and abundance in the May River, South Carolina, USA

Black drum Pogonias cromis, red drum Sciaenops ocellatus, silver perch Bairdiella chrysoura, and spotted seatrout Cynoscion nebulosus belong to the family Sciaenidae and are commonly found in South Carolina (USA) estuaries. Fish within this family produce sounds that are associated with courtship behavior and spawning. By listening to estuarine soundscapes, we can identify spawning aggregations. In this study, our objectives were to investigate long-term patterns of black drum, silver perch, spotted seatrout, and red drum calling and chorusing (i.e. indicative of spawning) over a 6 yr time span; identify any shifts in seasonal sound production from one year to the next; and examine the relationship between chorusing and young-of-the-year (YOY) abundance collected through haul seines. We found that in years with warmer springs, black drum, silver perch, and spotted seatrout began chorusing earlier and had longer chorusing seasons than in the years with cooler temperatures. Inversely, cooler temperatures during late summer led to earlier and longer spawning seasons for red drum. We detected the appearance of YOY in the estuary approximately 1 mo after initiation of the chorusing season. Silver perch were the most abundant in the spring, spotted seatrout during the summer, and red drum during the fall. Additionally, we found positive correlations between chorusing and YOY abundance. In years with longer chorusing seasons, we detected higher abundance of silver perch, spotted seatrout, and red drum YOY than in the years with shorter chorusing periods. These patterns provide supporting evidence that passive acoustics can aid inmonitoring reproductive output of an estuary.

Amending survey design to improve statistical inferences: Monitoring recruitment of juvenile reef fish in the eastern Gulf of Mexico

Many species of interest to management and conservation remain data-limited, and the data that are available are often unable to produce statistically reliable population trends. We examined 10 years of juvenile reef fish catch data from two gear-specific, fishery-independent surveys in the eastern Gulf of Mexico to assess our ability 1) to characterize population trends for various reef species sampled using haul seines or otter trawls and 2) to amend our survey, as logistics would allow, to improve those characterizations. Species richness, catch-per-unit-effort, and length-frequency distributions were generally similar between gear types, suggesting a single survey (i.e., one gear type) may be sufficient. Simulation-based power analyses for the reef fish species indicated that overall, otter trawl data provided greater power for detecting trends over a 10-year period (41–75 % probability to detect a 50 % change in abundance) than haul seine data (27–52 %). Likewise, otter trawl data provided greater power for detecting trends from one year to the next (22–53 % probability to detect a 50 % change in abundance in one year) than haul seine data (15–33 %). Simplifying data collection from two surveys to a single, trawl-only survey (and approximately doubling the number of trawl tows) was more efficient, more effective, and more powerful (64–91 % for the amended design with more tows) in detecting abundance trends. Furthermore, by increasing sample size but retaining all other design elements, the data collected during the trawl survey before and after the change remain comparable; the time series was not interrupted. These changes increase our confidence in estimating population trends, predicting productivity, and informing management and conservation decisions.

The geometry and dynamics of Danish anchor seine ropes on the seabed

Abstract We present a two-dimensional kinematic description of the geometry and dynamics of the ropes of demersal seines during deployment, towing, and hauling, using piriform curves. Piriforms (which means pear shaped) are relatively simple analytical curves, which we parameterize, using basic positional and operational data from typical Danish anchor seine hauls. We then demonstrate how we can estimate the area fished, and the speed, direction and angle of attack of any part of the seine net rope, at any time during the fishing process. This sort of information is fundamental to a better understanding of the capture process of demersal seines, their whole gear selectivity, and their environmental impact.

Short-term Estimate of Finfish Bycatch Discards in the Inshore Artisanal Shrimp Fishery of Guyana

The artisanal shrimp fishery in Guyana is important for livelihood and food security, involving around 300 vessels owned and crewed exclusively by Guyanese nationals. This fishery uses Chinese seines and operates in major river estuaries. It targets penaeid shrimp, but also retains some finfish and is known to discard a significant but undocumented quantity of smaller finfish bycatch. The lack of knowledge regarding the bycatch is a concern for fishery management and biodiversity conservation. In this study, we quantify for the first time the finfish bycatch discards through onboard observations (July—August 2016) of a single typical vessel operating in the Demerara estuary. Wet weights of the total catch, retained catch, and finfish discards were recorded separately for each of 76 seine hauls, and subsequently presented as catch rates per trip, catch rates per seine haul (kg/haul), and catch rates standardized per hour of seine net soak—time (kg/hr). A sub—sample of finfish discards was taken from every haul to determine taxonomic composition and species—specific length frequencies. Examination of 2,012 discarded finfish distributed among 32 species revealed high taxonomic diversity, none of which were considered vulnerable by the IUCN Red List. Most finfish discards were small (modal size class 5—7 cm fork length) and included juveniles of 15 species of importance to other fisheries in Guyana. On average, a standardized total catch rate of 14.8 kg was taken per hour of seine net soak—time, yielding 3.9 kg retained catch (shrimp and a few selected finfish), 10.3 kg of finfish bycatch discards, and 0.6 kg of miscellaneous invertebrate discards. This demonstrates significant wastage (finfish discards represent about 69% of the total catch weight) and potential for negative impact on biodiversity and other commercial fisheries. The information provided here addresses an important knowledge gap in the artisanal fisheries of Guyana.

Variation in Bluegill Catch Rates and Total Length Distributions among Four Sampling Gears Used in Two Wisconsin Lakes Dominated by Small Fish

AbstractMany Bluegill Lepomis macrochirus populations are dominated by fish ≤125 mm total length (TL) that may be underrepresented when using standard sampling gears. To identify efficient sampling methods for these populations, we compared catch per unit effort (CPUE) and TL frequency distributions of Bluegill captured in cloverleaf traps, boat electrofishing, mini‐fyke nets, and beach seine hauls from two northern Wisconsin lakes supporting populations dominated by fish ≤125 mm TL. Mean Bluegill CPUE ranged from 41 (SE = 11) fish per cloverleaf trap lift to 16 (SE = 8) fish per beach seine haul. Cloverleaf traps generally captured smaller Bluegill relative to other gears and were the only gear to consistently capture Bluegill ≤80 mm TL. Conversely, boat electrofishing captured the widest TL range of Bluegill, and fish ≥80 mm TL composed a greater proportion of catch (37%) relative to other gears. With few exceptions, the effort required to detect 10% or 25% changes in Bluegill CPUE was &gt;100 units of effort regardless of lake, sampling gear, or month. Furthermore, there was no consistency between lakes or months in terms of which sampling gear required the fewest number of samples to detect a 50% change in CPUE. Estimated units of effort needed to detect 10% or 25% changes in mean Bluegill TL were ≤16 for all sampling gears on the lake with consistently higher CPUE (i.e., more fish to measure per unit). In the lake with lower CPUE, cloverleaf traps consistently required less effort to detect changes in mean TL. We note that comparing sample size requirements among gears is not straightforward because gears are sampling differing segments of the Bluegill population. Our study emphasizes the importance of evaluating gear biases and sampling efficiency so that fisheries managers can develop suitable sampling protocols.

Effects of Nonnative Fishes on Commercial Seine Fisheries: Evidence from a Long-Term Data Set

Dozens of introduced exotic freshwater fish species inhabit the state of Florida. These nonnative fishes interact with freshwater commercial fisheries in a variety of ways, influencing catch abundance, composition, and revenue. Using a 22-year data set collected from a commercial haul seine fishery, we aimed to explore the dynamics of yield and revenue in relation to nonnative fishes, with emphasis on the suckermouth armored catfishes (Pterygoplichthys spp.). Using profit index metrics and the inverse Simpson’s diversity index, we found that non-native tilapia (Oreochromis spp.) and brown hoplo (Hoplosternum littorale) provided economic benefits while suckermouth armored catfishes seemed to disrupt catch consistency and lower profit index values. To reduce the negative impacts of the suckermouth armored catfishes and subsequently exert pressure on their population, we suggest marketing these edible fishes for human and/or animal consumption.

Precision and Relative Effectiveness of a Purse Seine for Sampling Age‐0 River Herring in Lakes

AbstractStock assessments for anadromous river herring, collectively Alewife Alosa pseudoharengus and Blueback Herring A. aestivalis, lack adequate demographic information, particularly with respect to early life stages. Although sampling adult river herring is increasingly common throughout their range, currently no standardized, field‐based, analytical methods exist for estimating juvenile abundance in freshwater lakes. The objective of this research was to evaluate the relative effectiveness and sampling precision of a purse seine for estimating densities of age‐0 river herring in freshwater lakes. We used a purse seine to sample age‐0 river herring in June–September 2015 and June–July 2016 in 16 coastal freshwater lakes in the northeastern USA. Sampling effort varied from two seine hauls to more than 50 seine hauls per lake. Catch rates were highest in June and July, and sampling precision was maximized in July. Sampling at night (versus day) in open water (versus littoral areas) was most effective for capturing newly hatched larvae and juveniles up to ca. 100 mm TL. Bootstrap simulation results indicated that sampling precision of CPUE estimates increased with sampling effort, and there was a clear threshold beyond which increased effort resulted in negligible increases in precision. The effort required to produce precise CPUE estimates, as determined by the CV, was dependent on lake size; river herring densities could be estimated with up to 10 purse‐seine hauls (one‐two nights) in a small lake (&lt;50 ha) and 15–20 hauls (two‐three nights) in a large lake (&gt;50 ha). Fish collection techniques using a purse seine as described in this paper are likely to be effective for estimating recruit abundance of river herring in freshwater lakes across their range.

Capture efficiency of a fine mesh seine in a large river: Implications for abundance, richness, and diversity analyses

Seining is a commonly used method for sampling fishes in shallow water, but studies that rely on data collected by seining rarely include corrections based on varied capture efficiencies for species or size classes, or account for false negative errors of detection. We sampled fishes in shallow, nearshore areas of a large river using a fine-mesh seine within a blocknet to estimate capture efficiencies for age-0 and yearling-and-older (YAO) fishes, make comparisons among species (within age groups), and determine if capture efficiencies were affected by water depth and aquatic vegetation cover. We also estimated the proportions of sites that individuals were present but not detected for each species, compared estimated taxa richness and Shannon diversity index values to true values, and determined if richness estimates were affected by water depth and aquatic vegetation cover. We found that capture efficiencies of age-0 fishes were not affected by depth, but did differ among four levels of vegetation cover and these relationships differed among species. Capture efficiencies differed among YAO species (range of species-specific means = 0.17–0.93), but were not affected by vegetation cover or depth. Total abundance of age-0 and YAO fishes (summed across species) captured during the first seine haul were highly correlated with true abundance (age-0 r = 0.96; YAO r = 0.95) but underestimated. Species and age-specific captures from the first seine haul were also highly correlated with true abundance. Finally, proportions of false negative errors of detection were typically higher for YAO than age-0 fishes, and estimated taxa richness and Shannon diversity were correlated with true values, but generally underestimated. Numerous biotic and abiotic factors appear to drive wide variations in capture efficiencies and false negative errors of detection among species, so results from any one study are likely only applicable to particular species. However, seining is an adequate method for investigating within species or total relative abundance (summed across species) trends. Further, seining-based abundance estimates are likely adequate for identifying habitat features associated with relatively high and low catches for a given species. Therefore, seining may be an effective method for comparing these values across sites to gain insights about what types of habitat or locations are most productive for nearshore fishes.

The Habitat Preferences of the Data Deficient, Cambarus spicatus

The Broad River Spiny crayfish, Cambarus spicatus, is endemic to the Broad River and some of its tributaries. Few life history studies of C. spicatus have caused the IUCN to list it as data deficient. The goal of this study was to determine the impacts of land development on the distribution of C. spicatus. In the summer of the 2017, the West Liberty University Crayfish Conservation Research Lab surveyed the Catawba watershed in North Carolina and the Broad and Saluda watersheds in South Carolina in search of C. spicatus. A standard protocol of ten seine hauls per riffle was implemented in one hundred and twenty-three streams. Dip nets were used in addition to seines to survey the banks of the streams. ArcMap, an application of ArcGIS, was utilized by adding layers such as land cover and a buffer around each collection area which provided land type percentages for each survey site. Six individuals from four sites in North Carolina and one individual from South Carolina were collected out of a total of one-hundred and twenty-three sites. According to the models, C. spicatus was least likely to be found in areas developed for agriculture and urban development. This study provides strong evidence that land development is negatively impacting C. spicatus distribution. Additional studies are needed throughout the species range to make a final determination that land development has a negative impact on C. spicatus.

Crayfishes of the Potomac River Basin in West Virginia

The high level of endemism displayed by native crayfish taxa, in addition to the recognized displacement abilities of nonindigenous crayfish such as Faxonius virilis and Procambarus acutus represents a serious threat to indigenous crayfish populations. Other major conservation threats to native crayfish fauna in the eastern portion of West Virginia include land development and land-use practices. The goal of this study was to compare recent and historical species distributions and assess conservation standings of native and nonindigenous crayfishes of the Potomac River Basin in West Virginia. Between June and October of 2007 historical and semi-randomly selected sites were sampled throughout the basin. Abundance was determined by catch per unit effort (CPUE) for ten seine hauls. Morphometric data including total carapace length, propodus length, and palm length were recorded in millimeters for each species. Life history parameters were determined from collections made during the study. Native species collected included Cambarus bartonii, Cambarus carinirostris, and Faxonius obscurus. Introduced species collected included Faxonius virilis and Procambarus zonangulus. C. bartoni was present in the Cacapon, North Branch Potomac, Potomac Direct Drains, and South Branch Potomac. F. obscurus was absent from Potomac Direct Drains, and C. carinirostris was only present in the South Branch Potomac. F. virilis and P. zonangulus were only present in Potomac Direct Drains. Though F. limosus was reported in 1989, no specimens were recovered during over the course of this survey, which indicates possible extirpation from the West Virginia portion of its range.

Quantifying Seining Detection Probability for Fishes of Great Plains Sand‐Bed Rivers

AbstractSpecies detection error (i.e., imperfect and variable detection probability) is an essential consideration when investigators map distributions and interpret habitat associations. When fish detection error that is due to highly variable instream environments needs to be addressed, sand‐bed streams of the Great Plains represent a unique challenge. We quantified seining detection probability for diminutive Great Plains fishes across a range of sampling conditions in two sand‐bed rivers in Oklahoma. Imperfect detection resulted in underestimates of species occurrence using naïve estimates, particularly for less common fishes. Seining detection probability also varied among fishes and across sampling conditions. We observed a quadratic relationship between water depth and detection probability, in which the exact nature of the relationship was species‐specific and dependent on water clarity. Similarly, the direction of the relationship between water clarity and detection probability was species‐specific and dependent on differences in water depth. The relationship between water temperature and detection probability was also species dependent, where both the magnitude and direction of the relationship varied among fishes. We showed how ignoring detection error confounded an underlying relationship between species occurrence and water depth. Despite imperfect and heterogeneous detection, our results support that determining species absence can be accomplished with two to six spatially replicated seine hauls per 200‐m reach under average sampling conditions; however, required effort would be higher under certain conditions. Detection probability was low for the Arkansas River Shiner Notropis girardi, which is federally listed as threatened, and more than 10 seine hauls per 200‐m reach would be required to assess presence across sampling conditions. Our model allows scientists to estimate sampling effort to confidently assess species occurrence, which maximizes the use of available resources. Increased implementation of approaches that consider detection error promote ecological advancements and conservation and management decisions that are better informed.

Habitat features not water variables explain most of fish assemblages use of sandy beaches in a Brazilian eutrophic bay

The influence of water variables and the availability of complex bottom habitats in the sublittoral zone on surf-zone fish assemblages of sandy beaches in a Brazilian eutrophic bay were assessed. In total, 64 seine hauls were carried out bimonthly between October 2012 and September 2013 in two beaches located within a marine-estuarine transitional zone in Guanabara Bay and <1 km apart to each other. These beaches share very similar geomorphological and hydrodynamic conditions, but the sublittoral zone of Urca Beach is more structurally-complex because of the presence of artificial structures made of concrete and beds of seagrass and drifting macroalgae, in contrast to the more homogeneous sandy substrate found in Dentro Beach. A total of 1257 fish were caught, with H. clupeola (N = 640), A. brasiliensis (N = 161), T. carolinus (N = 123) and T. goodei (N = 91) accounting for the dominant species. Urca and Dentro beaches shared few similarities in terms of fish species composition, and no seasonal or spatial difference was found for fish richness, abundance, and biomass. Except for the pelagic and planktivorous H. clupeola, which were more abundant in the seine hauls performed in Dentro Beach, the other dominant fish species were more abundant in the hauls conducted in Urca Beach. These findings confirmed the hypothesis that the availability of complex habitats in the nearby sublitoral zones of sandy beaches may lead to positive effects on their associated fish assemblages probably by the increased availability of feeding and spawning sites. Our paper also revealed that water variables were also important, but their effects only explained partially the seasonal variations of few species, agreeing however with the broad consensus of the function of sandy beaches as nursery grounds. Despite the interesting applied potential for fish management, the role of complex habitats in sandy beaches should be better investigated before any measure toward habitat manipulation and enrichment were carried out.

Optimal sampling effort required to characterize wetland fish communities

Wetlands are increasingly in peril as a result of human activities. In the Laurentian Great Lakes, coastal wetlands provide essential habitats for many fishes. Consequently, efficient sampling approaches for wetland fishes are needed for effective management. We employed a repeat-sampling strategy using a seine to collect fishes from seven wetlands. The data set was used to develop guidance for optimizing wetland fish sampling. To meet richness targets, the required number of sampling sites decreases as sampling intensity increases. Half the number of sites was required when three seine hauls per site were done compared with one haul. On average, 97 one-haul sites were required to detect 90% of species, whereas only 47 three-haul sites were required. Sampling effort is predicted to be greater in areas with more species and larger wetlands. The number of individuals and sites needed to detect 90% of species increased exponentially as species richness increased, and the number of individuals needed was positively related to wetland area. The use of block nets did not improve species detection or affect the composition.

Boat Propeller Scarring of Seagrass Beds in Lower Chesapeake Bay, USA: Patterns, Causes, Recovery, and Management

Seagrass beds are subject to numerous anthropogenic influences, including nutrient pollution, shoreline development and modification, and overfishing. Direct human impacts on seagrass though, such as through contact with boat propellers and fishing gear, remains relatively uninvestigated. Here, we use 26 years of aerial imagery and 3 years of ground surveys to explore the degree, distribution, and recovery of scarring in seagrass beds as the result of boat propellers in lower Chesapeake Bay, USA, specifically from commercial haul seine fishing activity. We find that propeller scarring is extensive, particularly on the western shore of the Bay, where pressure from haul seining is more intense. In two areas with the most intense scarring, Browns Bay and Poquoson Flats, annual total length of scars averaged 5575 and 3206 m, respectively. Despite the considerable presence of observable scarring, an individual scar generally persisted for only 2.7 years on average, implying quick recovery, aided by the diverse reproductive habits of the two seagrasses in this region, Zostera marina and Ruppia maritima. Moreover, regulations adopted by the regulary agency responsible for protecting marine habitats in Chesapeake Bay, the Virginia Marine Resources Commission, concerning the timing of haul seining in response to these findings reduced the frequency of new scars 43% at Browns Bay and 90% at Poquoson Flats since 2003. These results demonstrate that swift and decisive management action, in cooperation with relevant science, can lead to effective conservation of underwater grasses.

English

Abstract In 2015, a survey of Tomlinson Run State Park (TRSP) located in Hancock County, West Virginia USA was completed. Thirty stations, each 100m long, were randomly selected using ArcGIS for both intermittent and perennial stream reaches. Sites were sampled by performing ten seine hauls at each randomly selected station and scored using an Ohio EPA Qualitative Habitat Evaluation Index (QHEI) to obtain qualitative habitat data. Ponds and impoundments were trapped for crayfish using baited crayfish/minnow traps. Burrows found in wetlands and seeps were excavated to determine TRSP burrowing crayfish species composition. In total, 471 crayfish of four species (Cambarus carinirostris, Cambarus monongalensis, Cambarus robustus and Orconectes obscurus) were collected. A statistically significant correlation existed between QHEI score and CPUE for C. carinirostris on intermittent streams. Cambarus monongalensis was the sole burrowing species encountered while C. carinirostris was only collected from intermittent stations (CPUE = 0.12). O. obscurus was the most common species collected from perennial streams (CPUE = 0.95) while Cambarus robustus was the rarest species (CPUE = 0.09) encountered in Tomlinson Run State Park. The crayfish fauna of TRSP is typical for the Upper Ohio River Valley, and at the present time, all species appear stable.

Crayfish diversity and distribution of tomlinson run state park, hancock county, West Virginia.

In 2015, a survey of epigean crayfish of Tomlinson Run State Park was conducted. The park is located in Hancock County in West Virginia’s northern panhandle. A preliminary habitat survey was conducted to map all reaches of intermittent and perennial streams as well as other crayfish habitats. Following the survey for habitat, 30 stations, each 100m long, were randomly selected using ArcGIS for both intermittent and perennial streams. Sites were sampled by performing ten seine hauls in best available habitat throughout the reach and scored using an Ohio EPA QHEI form to obtain qualitative habitat data. In order to minimize impacts within the park, all crayfish were identified to species upon capture and released following sampling at each station. In total, 471 crayfish were collected during the survey out of which four species were identified: Cambarus carinirostris, Cambarus monogalensis, Cambarus robustus, and Orconectes obscurus. No statistically significant relations between QHEI score vs. CPUE (catch per unit effort) were shown, but O. obscurus demonstrated a slightly positive correlation with increased score while C. carinirostris demonstrated a slightly negative correlation to increased score. Cambarus monogalensis was collected from three large forested seeps. Only C. carinirostris were collected from intermittent stations with overall CPUE of 0.12 crayfish per haul. CPUE scores for perennial stations indicated 1.43 crayfish per haul, but when split by species, C. carinirostris had lower CPUE (0.39) compared to O. obscurus (0.95). C. robustus had the lowest CPUE (0.09) and was the rarest species encountered in Tomlinson Run State Park.