Boat Movements Research Articles

A bi-level model for state and county aquatic invasive species prevention decisions

Recreational boats are important vectors of spread of aquatic invasive species (AIS) among waterbodies of the United States. To limit AIS spread, state and county agencies fund watercraft inspection and decontamination stations at lake access points. We present a bi-level model for determining how a state planner can efficiently allocate inspection resources to county managers, who independently decide where to locate inspection stations. In our formulation, each county manager determines a set of optimal plans for the locations of inspection stations under various resource constraints. Each plan maximizes inspections of risky boats that may carry AIS from infested to uninfested lakes within the county. Then, the state planner selects the set of county plans (i.e., one plan for each county) that maximizes the number of risky boats inspected throughout the state subject to a statewide resource constraint. We apply the model using information from Minnesota, USA, including the infestation status of 9182 lakes and estimates of annual numbers of boat movements from infested to uninfested lakes. Comparison of solutions of the bi-level model with solutions of a state-level model where a state planner selects lakes for inspection stations statewide shows that when state and county objectives are not aligned, the loss in efficiency at the state-level can be substantial.

Effects of an Offshore Sailing Competition on Anthropometry, Muscular Performance, Subjective Wellness, and Salivary Cortisol in Professional Sailors.

Evidence regarding the impact of offshore sailing on fatigue and readiness variables is conspicuous by its absence. This study investigated the acute effects of an offshore sailing regatta on anthropometry, muscular performance, subjective recovery, and salivary biomarker cortisol. Ten professional offshore sailors from a mixed-sex crew partook in the study (N = 10; mean [SD] age = 32.2 [3.96]y; stature = 179.1 [7.30]cm; body mass = 84.2 [12.1]kg). The race involved 3 offshore legs over a 3-week period. Baseline measures of anthropometry, lower- and upper-body muscular function, perceptions of subjective wellness, and salivary cortisol were assessed 3hours prior to competition (ie,before the first leg). These measures were repeated within 30minutes after the cessation of each leg. During each leg, boat movements were recorded via global positioning system units. There were significant reductions in lower (effect size [ES] = 0.49) and upper muscular (ES = 0.21) functions, as well as in subjective wellness (ES = 1.65). Salivary cortisol levels increased (ES = 0.84). These results demonstrate that, during an intensified period of sailing competition, fatigue will progressively increase. This may impede sailing performance by reducing physical and cognitive efficiency. Furthermore, countermovement jump, handgrip strength, perception of subjective wellness, and cortisol concentration appear to be sensitive measures for monitoring fatigue and readiness in professional sailors.

Controlling the flight on double-handed foiling catamarans: The role of shared equipment on the crew members' mutual modes of regulation

The purpose of this study was to contribute to the understanding of the role of shared sport equipment in the collective coordination of a team. It was conducted within an enactive approach of human cognition by mobilizing the methodological tools and methods of the Course of Action framework. Six crew members of hydrofoil sailing catamarans participated in this study. Data collection consisted in video-recording training sessions followed by individual self-confrontation interviews. A qualitative analysis of the data allowed typical modes of regulation of the flight to be characterized from each crew member's perspective. Three main modes of regulation were identified. All of them involved either salient perception of the boat's movements, or actions directed to regulating the boat’s movement. In the discussion, we propose a distinction between three types of collective sport situations, regarding the role of the material environment of athletes in their coordination. This distinction opens new perspectives both for future research on team coordination, and for pedagogical and training implications.

Changing Oar Rotation Axis Position Increases Catch Angle During Indoor and In-Field Para-Rowing: A Randomized Crossover Trial Verified by a Repeated Measurement Trial

A long rowing stroke length is crucial for adequate rowing performance. Therefore, the relocation of the oar from traditional “in front” (NORM) to “behind the rotation axis” (GATE) may increase (para) rowing performance. Thus, 15 able-bodied rowers (21.4 ± 3.6 years; 187 ± 8 cm; 85.4 ± 8.2 kg) completed indoor TANK rowing 2 min TimeTrials (2 min-TT) of GATE and NORM in a randomized order. Additionally, one elite Paralympic oarsman (37 years, 185 cm, 67 kg) performed a multiple single case in-field BOAT testing (24x2min-TT of GATE and NORM in a randomized order). GATE revealed significantly larger catch angles during TANK (+97.1 ± 120.4%; p = 0.001, SMD = 0.84) and BOAT (+11.9 ± 3.2%; p < 0.021; SMD = 2.69; Tau-U = 0.70) compared to NORM. While total stroke length, rowing power, and work per stroke increased in GATE during TANK (p < 0.010, SMD > 0.634), no such significant changes of these performance parameters between GATE and NORM were observed during BOAT (p > 0.021; SMD < 0.58; Tau-U < 0.29). Rowing economy-related parameters (power or speed per oxygen uptake) and boat speed also showed no significant differences between GATE und NORM during BOAT (p > 0.61; SMD < 0.31; Tau-U < 0.19). The shape of the force–angle curve (position of peak force and ratio between average and maximal force) remained unaffected from GATE during both TANK (p > 0.73, SMD < 0.1) and BOAT (p > 0.63; SMD < 0.60; Tau-U < 0.27). In conclusion, GATE shifted the entire rowing stroke towards the catch (+6.6 ± 1.8°) without notably affecting relevant performance parameters during BOAT. Particularly during crew rowing, the minimization of detrimental boat movements for perfect synchrony should be aimed for. Accordingly, the combined application of GATE and NORM (for different athletes in crew boats) may be beneficial for rowing synchronization.

Performance of Basic Life Support by Lifeboat Crewmembers While Wearing a Survival Suit and Life Vest: A Randomized Controlled Trial.

Introduction: Crewmembers of the “Royal Netherlands Sea Rescue Institution” (KNRM) lifeboats must wear heavy survival suits with integrated lifejackets. This and the challenging environment onboard (boat movements, limited space) might influence Basic Life Support (BLS) performance. The primary objective of this study was to assess the impact of the protective gear on single-rescuer BLS-quality.Material and Methods: Sixty-five active KNRM crewmembers who had recently undergone a BLS-refresher course were randomized to wear either their protective gear (n = 32) or their civilian clothes (n = 33; control group) and performed five 2-min sessions of single rescuer BLS on a mannequin on dry land. BLS-quality was assessed according to Dutch and European Resuscitation guidelines. A between group analysis (Mann-Whitney U) and a repeated within group analysis of both groups (Friedman test) were performed.Results: There were no major demographic differences between the groups. The protective gear did not significant impair BLS-quality. It was also not associated with a significant increase in the perceived exertion of BLS (Borg's Rating scale). Compression depth, compression frequency, the percentage of correct compression depth and of not leaning on the thorax, and ventilation volumes in both groups were suboptimal when evaluated according to the BLS-guidelines.Conclusions: The protective gear worn by KNRM lifeboat-crewmembers does not have a significant influence on BLS-quality under controlled study conditions. The impact and significance on outcome in real life situations needs to be studied further. This study provides valuable input for optimizing the BLS-skills of lifeboat crewmembers.

Remediation criteria for gasworks-impacted sediments: Assessing the effects of legacy hydrocarbons and more recent metal contamination

Historical contamination of sediments from industries that commenced before environmental regulations were commonplace is prevalent in many large cities. This contamination is frequently overlain and mixed with more recent urban contamination. The remediation of contaminated sites is often a very expensive exercise and the final remediation criteria often reflect a trade-off between protecting human and ecological health and the finances of those deemed responsible for the site clean-up. In this study, we describe an assessment of estuarine sediments impacted historically by contamination from a gasworks site. The major historical sediment contaminants included polycyclic aromatic hydrocarbons (PAHs) and other petroleum-related hydrocarbons (TRHs). Elevated concentrations of metals exist throughout the city region due to historical pollution and ongoing urban stormwater discharges. Equilibrium partitioning models were used to consider the influence on the bioavailability of PAHs of both natural sedimentary organic carbon and forms of black carbon (pyrogenic carbon - coal tars, charcoal). The strongest predictor of the observed sublethal toxicity to amphipod and copepod reproduction was a combination of total PAHs and metals (primarily Cu, Pb and Zn). Total PAHs was the strongest predicting variable for toxicity to organism survival. While high total PAH concentrations were attributed to the former gas works, high background concentrations of metals existed throughout much of this region of the estuary. Thus, without remediation at the estuary-scale, resuspension of the surrounding sediments by tidal currents and boat movements is predicted to re-contaminate remediated areas with sediments that may continue to cause chronic toxicity due to metals. The assessment indicated that remedial actions that remove or isolate sediments that caused toxicity to benthic organism survival would lead to significant improvements in ecosystem health, but toxicity to organism reproduction may remain at similar levels that exist throughout much of this region of the estuary due to high metal concentrations.

Is Pseudanodonta complanata the most vulnerable of widespread European species of unionids? An intense stress test leading to a massive die‐off

Abstract This article reports a large‐scale die‐off of approximately one‐third of the unionid mussels inhabiting a shallow, naturally eutrophic, floodplain lake (Zalew Pińczowski), which took place within the space of just a few days. Mortality was the highest in Pseudanodonta complanata (81%), followed by Unio pictorum (58%), Anodonta cygnea (26%), Unio tumidus (15%), and Anodonta anatina (5%). It was significantly related to mussel size (age) only in A. cygnea, with the mortality rate higher in smaller (young) mussels. Pseudanodonta complanata was already the rarest species in the lake, and the number of survivors decreased to such an extent as to trigger a possible Allee effect. The most likely cause of the die‐off was a motor‐boating incident that had directly preceded the die‐off. Analysis of the water samples collected just after the die‐off revealed an extremely high concentration of phosphate (up to 0.5 mg dm−3) and nitrite (up to 0.06 mg dm−3). We suggest that the boat movements must have disturbed the lake sediments, thereby disrupting the mussels' physiology and causing mass mortality. The high sensitivity of P. complanata to environmental stress suggests that it may be an effective umbrella species for the protection of co‐occurring mussel species in eutrophic lakes.

Assessment of recreational boating as a vector for marine non-indigenous species on the Atlantic coast of Canada

We developed a new predictive approach to evaluate the relative invasion hazard posed by recreational boats as vectors for non-indigenous species (NIS) in marine ecoregions on the Atlantic coast of Canada. It combines data from behavioral boater questionnaires, surveys of boat macrofouling, and an extensive NIS monitoring program in marinas. The relative invasion hazard posed by boats in nine marine ecoregions was estimated by combining information on NIS infestation levels in source ecoregions, the probability that boats will be fouled, boat movements and environmental similarity between source and receiving marinas, and estimates of annual recreational traffic within and between ecoregions. A total of 52.1% of surveyed boats had macrofouling on hull or niche areas, suggesting a high potential for NIS transport. High-risk boats were those that had spent extended periods in water, traveled extensively from invaded locations, and received little maintenance. Further, the high degree of connectivity between and within ecoregions, and high survival probabilities of NIS, highlight the threat of NIS introduction and spread via recreational boating in Atlantic Canadian waters. Of all Atlantic Canadian ecoregions, the Scotian Shelf ecoregion was classified as having the “Highest” Final Hazard score. However, boats with Intermediate to Highest scores travel to most ecoregions, underlining the importance of this vector to the introduction and spread of NIS in Atlantic Canadian coast. A simulated out-of-water cleaning after 3 months reduced the hazard in ecoregions with greater scores.

Proliferation of &amp;lt;i&amp;gt;Salvinia molesta&amp;lt;/i&amp;gt; at Lake Kyoga Landing Sites as a Result of Anthropogenic Influences

Salvinia molesta (native of south-eastern Brazil) is a free floating aquatic fern that has spread to several countries around the globe including Uganda. Under optimum growing conditions, the plant is capable of spreading rapidly where it can have immense environmental, economic and human health impacts. Thick mats of the weed have been recorded in some parts of Lake Kyoga, Uganda where it hinders the abstraction of water, docking and boat take-off, bathing and swimming activities. Therefore this study aimed to determine the extent of S. molesta at selected landing sites in Lake Kyoga and the influence of anthropogenic activities on the weed coverage as well as the effect of physico-chemical parameters of the water on the development of the weed. Quadrats were used to ascertain the coverage of S. molesta while the physico-chemical parameters were determined by standard methods. The results showed significant positive correlation of S. molesta weed coverage with phosphates (PO4-P) and negative correlations with pH, dissolved oxygen (DO) and water flow rate. Though statistically insignificant waste sites recorded the highest overall S. molesta coverage (82.61 ± 21.12 m2) per 400 m2 quadrat followed by boat docks (82.24 ± 19.45 m2), gardens (50.93 ± 11.82 m2) and finally fishing areas (27.94 ± 5.93 m2) respectively. The overall weed coverage was highest around the shoreline locations of Acholi inn landing site (101.72 ± 22.89 m2 per 400 m2) followed by Masindi port (60.39 ± 15.64 m2), Waitumba (41.89 ± 10.55 m2) and the least in the offshore location at Kayei landing site (39.71 ± 10.17 m2). Salvinia molesta distribution in Lake Kyoga is linked to nutrient (PO4-P) supply, proximity to the shoreline and the associated anthropogenic activities. Hence waste sites, gardens and boat docks enhance S. molesta invasion in Lake Kyoga. Therefore, sources of nutrients (phosphates) into Lake Kyoga that favour the proliferation of S. molesta should be minimized through adequate waste treatment and prohibition of cultivation close to the lake. Salvinia molesta coverage along the routes of moving boats should also be contained so as to reduce the spread of the weed in the lake through boat movements. Furthermore, eradication efforts of S. molesta weed in Lake Kyoga should be heightened at the shoreline areas of the lake in the various landing sites within the lake basin.

Rocking the boat: does perfect rowing crew synchronization reduce detrimental boat movements?

In crew rowing, crew members need to mutually synchronize their movements to achieve optimal crew performance. Intuitively, poor crew coordination is often deemed to involve additional boat movements such as surge velocity fluctuations, heave, pitch, and roll, which would imply lower efficiency (eg, due to increased hydrodynamic drag). The aim of this study was to investigate this alleged relation between crew coordination and boat movements at different stroke rates. Fifteen crews of two rowers rowed in a double scull (ie, a two-person boat) at 18, 22, 26, 30, and 34 strokes per minute. Oar angles (using potentiometers) and movements of the boat (using a three-axial accelerometer-gyroscope sensor) were measured (200Hz). Results indicated that crew synchronization became more consistent with stroke rate, while surge, heave, and pitch fluctuations increased. Further, within each stroke rate condition, better crew synchronization was related to less roll of the boat, but increased fluctuations regarding surge, heave, and pitch. Together this demonstrates that while better crew synchronization relates to enhanced lateral stability of the boat, it inevitably involves more detrimental boat movements and hence involves lower biomechanical efficiency.

A tough egg to crack: recreational boats as vectors for invasive goby eggs and transdisciplinary management approaches.

Non-native invasive species are a major threat to biodiversity, especially in freshwater ecosystems. Freshwater ecosystems are naturally rather isolated from one another. Nonetheless, invasive species often spread rapidly across water sheds. This spread is to a large extent realized by human activities that provide vectors. For example, recreational boats can carry invasive species propagules as "aquatic hitch-hikers" within and across water sheds. We used invasive gobies in Switzerland as a case study to test the plausibility that recreational boats can serve as vectors for invasive fish and that fish eggs can serve as propagules. We found that the peak season of boat movements across Switzerland and the goby spawning season overlap temporally. It is thus plausible that goby eggs attached to boats, anchors, or gear may be transported across watersheds. In experimental trials, we found that goby eggs show resistance to physical removal (90mN attachment strength of individual eggs) and stay attached if exposed to rapid water flow (2.8m·s(-1)for 1h). When exposing the eggs to air, we found that hatching success remained high (>95%) even after eggs had been out of water for up to 24h. It is thus plausible that eggs survive pick up, within-water and overland transport by boats. We complemented the experimental plausibility tests with a survey on how decision makers from inside and outside academia rate the feasibility of managing recreational boats as vectors. We found consensus that an installation of a preventive boat vector management isconsidered an effective and urgent measure. This study advances our understanding of the potential of recreational boats to serve as vectors for invasive vertebrate species and demonstrates that preventive management of recreational boats is considered feasible by relevant decision makers inside and outside academia.

A generic rabies risk assessment tool to support surveillance

The continued spread of rabies in Indonesia poses a risk to human and animal populations in the remaining free islands, as well as the neighbouring rabies-free countries of Timor Leste, Papua New Guinea and Australia. Here we describe the development of a generic risk assessment tool which can be used to rapidly determine the vulnerability of rabies-free islands, so that scarce resources can be targeted to surveillance activities and the sensitivity of surveillance systems increased. The tool was developed by integrating information on the historical spread of rabies, anthropological studies, and the opinions of local animal health experts. The resulting tool is based on eight critical parameters that can be estimated from the literature, expert opinion, observational studies and information generated from routine surveillance. In the case study presented, results generated by this tool were most sensitive to the probability that dogs are present on private and fishing boats and it was predicted that rabies-infection (one infected case) might occur in a rabies-free island (upper 95% prediction interval) with a volume of 1000 boats movements. With 25,000 boat movements, the median of the probability distribution would be equal to one infected case, with an upper 95% prediction interval of six infected cases. This tool could also be used at the national-level to guide control and eradication plans. An initial recommendation from this study is to develop a surveillance programme to determine the likelihood that boats transport dogs, for example by port surveillance or regularly conducted surveys of fisherman and passenger ferries. However, the illegal nature of dog transportation from rabies-infected to rabies-free islands is a challenge for developing such surveillance.

Evaluation of Boat Movements Using the Differential-GPS in Canoe Sprint

Evaluation of Boat Movements Using the Differential-GPS in Canoe Sprint

REMOTE, a Wireless Sensor Network Based System to Monitor Rowing Performance

In this paper, we take a hard look at the performance of REMOTE, a sensor network based application that provides a detailed picture of a boat movement, individual rower performance, or his/her performance compared with other crew members. The application analyzes data gathered with a WSN strategically deployed over a boat to obtain information on the boat and oar movements. Functionalities of REMOTE are compared to those of RowX [1] outdoor instrument, a commercial wired sensor instrument designed for similar purposes. This study demonstrates that with smart geometrical configuration of the sensors, rotation and translation of the oars and boat can be obtained. Three different tests are performed: laboratory calibration allows us to become familiar with the accelerometer readings and validate the theory, ergometer tests which help us to set the acquisition parameters, and on boat tests shows the application potential of this technologies in sports.

Behaviour of walleye, Sander vitreus, and largemouth bass, Micropterus salmoides, exposed to different wave intensities and boat operating conditions during livewell confinement

Abstract During live‐release angling tournaments in North America, fish are typically retained in livewells onboard boats during the angling day. Mortality of fish occurs at some tournaments, and wave intensities and livewell conditions may influence mortality levels. This study used two species of fish targeted in live‐release angling tournaments in North America (largemouth bass Micropterus salmoides L. and walleye Sander vitreus L.) to quantify the response(s) of fish in livewells to different wave treatments. Video analyses revealed that largemouth bass were active during low intensity disturbances, but during violent boat movements tended to settle to the bottom of the livewell and orient to face the direction of the disturbance. Walleye were less active than bass for all treatments, and additionally did not orient to face the direction of disturbance, consequently contacting the side of the livewell during boat rocking. These results are considered in the context of mortality at live‐release tournaments.

Factors affecting traffic and anchoring patterns of recreational boats in Sydney Harbour, Australia

Management of recreational boating is typically based on measures of numbers of boats (e.g. marina berths, vessel registrations). Potential environmental impacts and safety aspects may, however, be a function of the number of boat movements and not of the total numbers of boats kept in a harbour. Therefore, a survey was designed to test hypotheses regarding the traffic and anchoring patterns of recreational boats in Sydney Harbour. Boat movements were visually counted for periods of 1 h in four locations in the estuary. The results indicate that recreational boating is the main component of all boat traffic, being composed chiefly by sailing yachts, with a small contribution of jet-skis. Traffic of leisure boats was more intense in summer than in winter. On weekends, there were more movements of recreational boats on sunny than on overcast/rainy conditions. Weather was not, however, a significant factor on weekdays. During the Sydney 2000 Olympic Games, the predicted increase in traffic and anchoring intensity by recreational boats was not consistent. In two out of four locations, the traffic of recreational boats during this special event was not significantly different than during baseline periods. The number of anchored boats was greater at North Harbour Aquatic Reserve (NHAR) and was positively correlated to boat traffic. Due to this observed correlation, managers can use the patterns of boat traffic to predict the patterns of anchored boats in this marine protected area. The large number of movements of sailing boats is an important issue to be considered in management of boat traffic, because this type of boat has restricted manoeuvrability and right of way over motorised recreational craft in most situations. This study quantified and identified clear patterns of recreational boat traffic. Managers can now use this information to develop strategies aiming at the improvement of boating safety and the prevention of potential environmental impacts due to the use of recreational boats in urban waterways.

The Effect of Boat Activity on Turbidity in a Shallow Broadland River

(1) Measurements of water turbidity and boat movements were made on a shallow Broadland River, the River Ant, above and below Barton Broad. (2) A simple experimental model of the form y = a + bekt was proposed and tested It describes the mechanism by which boats can influence turbidity. (3) Of three constants derived from the model, two were shown to be closely related to measured physical variables. (4) The model was used to predict water turbidities from typical boat movement patterns. This demonstrated that long-term build-up of boat induced turbidity through the holiday season was unlikely and that the major part of the turbidity in and below Barton Broad on the River Ant was due to algae, not to boating activity.