Abstract Marine protected areas (MPAs) and associated management measures are being implemented to conserve marine benthic species. To make effective decisions, marine managers need data on the distributions of species of interest and anthropogenic pressures, but also the potential connectivity between habitat patches. To explore how predictive modelling can be utilized in such a process, a model was developed to predict the distribution of northern sea fan, Swiftia pallida , habitat around parts of Scotland, Northern Ireland, and Ireland. The predicted distribution of suitable habitat was compared with spatial data on mobile bottom‐contacting fishing activity, and the location of MPAs designated for benthic features, and the management measures within MPAs that restrict mobile bottom‐contacting fishing activity, which is the main pressure‐causing activity that S. pallida are sensitive to. Over 20% of predicted suitable habitat is within MPAs, over 10% is within MPA management measures and over 48% is within areas that have experienced no bottom contacting‐fishing activity, which is significantly higher than the equivalent values for the study region as a whole. However, patches were identified that potentially experience above average levels of fishing activity and remain unmanaged, including within MPAs designated for associated features. The analysis also highlighted patches that could be candidates for monitoring recovery and the locations of unknown populations. For each patch of suitable habitat, the number of other patches within 22 km, a previously published estimate of dispersal distance for S. pallida , was used as a proxy for connectedness. Connectedness was estimated to be greatest for patches towards the centre and west of the study region. The results indicate how the outputs of predictive distribution models can be used in conjunction with other data to prioritize areas for surveys and identify locations where effective management may facilitate conservation or the recovery of benthic species.
Abstract The aim is to determine the environmental requirements, estimate the extent of suitable habitat for three sea pen species, and assess the implications for marine protected areas (MPAs). The sea pen Funiculina quadrangularis and the habitat associated with two further sea pen species, Virgularia mirabilis and Pennatula phosphorea, are of key conservation importance and are recommended for protection within MPAs. This study models their potential distributions using the MAXimum ENTropy algorithm and assesses these in relation to five possible marine protected areas (pMPAs) proposed for Scottish waters. Metrics relevant to assessing the efficacy of MPAs are also presented. Four environmental variables of prime importance for predicting the presence of all three species of sea pen were identified: mud, minimum salinity, depth, and gravel. The habitat suitability index increased with mud content. The modelled distribution of F. quadrangularis indicated a deeper distribution than V. mirabilis or P. phosphorea and was not present in sediment with gravel content above 30%. Pennatula phosphorea had the smallest area of suitable habitat, while V. mirabilis had the largest. The percentage predicted suitable area for each species that was encompassed by the five pMPAs ranged from 11% for F. quadrangularis to 15% for P. phosphorea. Some of the largest areas predicted as suitable for F. quadrangularis lay outside the pMPAs. The model results indicated differences in the environmental requirements of the three species of sea pen that can be linked to the autecology of each species. Patch sizes, calculated from a binary output of the model, were used to estimate the degree of habitat fragmentation, thereby giving a partial assessment of the adequacy criterion for these pMPAs. The results suggest that potential MPAs within the study area cover sizeable areas of potential sea pen habitat. However, further areas suitable for F. quadrangularis could be considered.
1. Poultry on farms are sometimes required to be killed in an emergency, such as during a disease epidemic, yet none of the available methods are ideal. Whole-house carbon dioxide (CO2) administration has practical advantages, but gives rise to welfare concerns. 2. The study measured the body temperature, respiration, cardiac and brain activity (EEG) responses of 10 adult hens placed in tiered cages in a deep pit house while the entire flock (28,000 end-of-lay hens) was killed with CO2. Video and thermographic images were also recorded. Liquid CO2 was injected into the building producing a gaseous concentration of 45% within 19 min. 3. Those hens nearest the gas delivery site showed delayed respiratory, cardiac and EEG responses compared with those at more distant locations. Although sub-zero temperatures were recorded in the immediate vicinity of some birds, body temperatures indicated that they did not die of hypothermia. 4. EEG characteristics strongly associated with unconsciousness were used to determine an unequivocal time to loss of consciousness; this ranged from 6·0 to 10·5 (average 7·8) min after onset of gas injection. Distinctive cardiac and respiratory responses were seen following gas exposure; in particular, birds responded to inhalation of CO2 by deep breathing. 5. The primary welfare concern is the duration of unpleasant respiratory effects, such as deep breathing, while the birds were substantively conscious. However, the concentration of CO2 to which the birds were exposed while conscious would not have stimulated nasal and oral nociceptors. Time to death varied between 12·0 and 22·1 min after gas delivery.
Measuring dispersal in rare sessile benthic species is important in the development of conservation measures such as MPA networks. However, efforts to understand dispersal dynamics for many species of conservation concern are hampered by a lack of fundamental life-history information. Here we present the first description of larvae of the fan mussel, Atrina fragilis, and examine key life-history traits that affect dispersal. Larval identification was accomplished using complementary molecular and morphologic techniques. Atrina-specific primers were designed by aligning Atrina COI sequences available in GenBank. As none of these were from UK specimens, primers were designed in the most conserved regions found across A. fragilis and its closest relative A. chautardi. A monthly time-series of zooplankton samples (2014–2015) suggests that A. fragilis follows the same pattern in spawning observed for other pinnids at temperate latitudes, with peak spawning in summer and winter. Average shell growth was estimated to be 6 μm d–1 based on presumed daily growth lines on larval shells. Measurements of the larval shell visible through the juvenile shell indicate a length of up to 770 μm at settlement. Using presumed daily growth lines, this translates into a pelagic larval duration of around 4 months.
Abstract Aim Given the paucity of data on the distribution of habitats and species for most marine species, particularly those that are rare and in need of protection, there is a need to model species distributions. Using the fan mussel, Atrina fragilis (Pennant 1777), as our case species, the aim of the study was to predict new areas of occurrence for A. fragilis , estimate the extent of potentially suitable areas, determine the proportion of these areas that are included in the recently designated nature conservation MPA s off the west of Scotland and identify possible environmental drivers in the distribution of A. fragilis . Location West coast of Scotland, UK . Methods Using a point process framework, we modelled presence‐only data, including historic records. A quadrat survey employing digital still photography was conducted in areas of high and low suitability to verify the model, and subsequently, a targeted survey was undertaken in areas predicted as highly suitable by the models using towed video cameras. Results Five environmental variables were of prime importance in explaining the distribution of A. fragilis . The results from the verification survey support model performance. Atrina fragilis was found in 80% of the targeted transects undertaken. Approximately 14% of the total area predicted as suitable for A. fragilis occurred within recently designated marine protected areas ( MPA s) indicating considerable potential for recolonization given suitable protection. Main conclusions The verified model suggests that limited presence‐only and historical records of rare species can perform well within a SDM framework allowing the identification of further suitable areas. The prominence of bathymetric ruggedness in the models is unexpected, given the understood ecological niche for A. fragilis and pinnids in general, but is consistent with the fact that seabed topography can offer protection from fishing pressure. These results will inform restoration objectives of the MPA network.
The lesser sandeel Ammodytes marinus is a key component of the North East Atlantic ecosystem but little is known about its distribution outside of fished areas. In this study, species distribution models were developed to predict the occurrence and density of sandeels in parts of the North Sea and Celtic Seas regions. A hurdle model was found to be the best fitting model with the highest predictive performance; model evaluation with independent data demonstrated that it had significant discrimination ability across the study region. Percentage silt was the most important variable in predicting occurrence, and percentage sand had a strong influence on density, consistent with past local studies. Slope was also a significant explanatory variable, especially for predicting density, as buried sandeels avoided strongly sloping areas such as the edges of sand banks. A predicted preferred depth range of 30-50 m was consistent with many previous studies, although the depth response did appear partially biased by the depth range investigated in the training data set. Overall, the predicted distribution did not indicate that there were large areas of unexploited habitat. However, some small areas known to be important to sandeel predators were identified by the model. The distribution model helps refine past inferences about sandeel availability to predators and indicates to marine planners potential areas where anthropogenic impacts should be considered.
Disease control measures require poultry to be killed on farms to minimize the risk of disease being transmitted to other poultry and, in some cases, to protect public health. We assessed the welfare implications for poultry of the use of high-expansion gas-filled foam as a potentially humane, emergency killing method. In laboratory trials, broiler chickens, adult laying hens, ducks, and turkeys were exposed to air-, N2-, or CO2-filled high expansion foam (expansion ratio 300:1) under standardized conditions. Birds were equipped with sensors to measure cardiac and brain activity, and measurements of oxygen concentration in the foam were carried out. Initial behavioral responses to foam were not pronounced but included headshakes and brief bouts of wing flapping. Both N2- and CO2-filled foam rapidly induced ataxia/loss of posture and vigorous wing flapping in all species, characteristic of anoxic death. Immersion in air-filled, high expansion foam had little effect on physiology or behavior. Physiological responses to both N2- and CO2-filled foam were characterized by a pronounced bradyarrythymia and a series of consistent changes in the appearance of the electroencephalogram. These were used to determine an unequivocal time to loss of consciousness in relation to submersion. Mean time to loss of consciousness was 30 s in hens and 18 s in broilers exposed to N2-filled foam, and 16 s in broilers, 1 s in ducks, and 15 s in turkeys exposed to CO2-filled foam. Euthanasia achieved with anoxic foam was particularly rapid, which is explained by the very low oxygen concentrations (below 1%) inside the foam. Physiological observations and postmortem examination showed that the mode of action of high expansion, gas-filled foam is anoxia, not occlusion of the airway. These trials provide proof-of-principle that submersion in gas-filled, high expansion foam provides a rapid and highly effective method of euthanasia, which may have potential to provide humane emergency killing or routine depopulation.
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