Social Group Size and Shelter Availability Influence Individual Metabolic Traits in a Social Fish

Group living is widespread among animal species and yields both costs and benefits. Presence of conspecifics can restrict or enhance the expression of individual behaviour, and the recent social environment is thought to affect behavioural responses in later contexts, even when individuals are alone. However, little is known about how social group size influences the expression of individual physiological traits, including metabolic rates. There is some evidence that shoaling can reduce fish metabolic rates but this variable may be affected by habitat conditions such as shelter availability via density-dependent processes. We investigated how social group size and shelter availability influence Eurasian minnow Phoxinus phoxinus metabolic rates estimated by respirometry. Respirometry trials were conducted on fish in isolation before and after they were housed for three weeks in a social treatment consisting in a specific group size (n = 4 or 8) and shelter availability (presence or absence of plant shelter in the experimental tank). Plant shelter was placed over respirometers for half of the duration of the respirometry trials, allowing estimation of minimum day-time and night-time metabolic rates in both conditions (in the presence or absence of plant shelter). Standard metabolic rate (SMR), maximum metabolic rate (MMR), and aerobic scope (AS) were also estimated over the entire trial. Minimum day-time and night-time metabolic rates estimated while in presence of plant shelter were lower than when estimated in absence of plant shelter, both before and after individuals were housed in their social treatment. After the social treatment, SMR were higher for fish that were held in groups of four as compared to that of fish held in groups of eight while MMR showed no difference. Plant shelter availability during the social treatments did not influence SMR or MMR. Our results suggest that social group size may directly influence energy demands of individuals, highlighting the importance of understanding the role of group size on variations in physiological traits associated with energy expenditure.

Integrating Evacuation and Storm Surge Modeling Considering Potential Hurricane Tracks: The Case of Hurricane Irma in Southeast Florida

Hurricane Irma, in 2017, made an unusual landfall in South Florida and the unpredictability of the hurricane’s path challenged the evacuation process seriously and left many evacuees clueless. It was likely to hit Southeast Florida but suddenly shifted its path to the west coast of the peninsula, where the evacuation process had to change immediately without any time for individual decision-making. As such, this study aimed to develop a methodology to integrate evacuation and storm surge modeling with a case study analysis of Irma hitting Southeast Florida. For this purpose, a coupled storm surge and wave finite element model (ADCIRC+SWAN) was used to determine the inundation zones and roadways with higher inundation risk in Broward, Miami-Dade, and Palm Beach counties in Southeast Florida. This was fed into the evacuation modeling to estimate the regional clearance times and shelter availability in the selected counties. Findings show that it takes approximately three days to safely evacuate the populations in the study area. Modeling such integrated simulations before the hurricane hit the state could provide the information people in hurricane-prone areas need to decide to evacuate or not before the mandatory evacuation order is given.

Group size influences individual metabolic traits in a social fish

Group living is widespread among animal species and yields both costs and benefits. Presence of conspecifics can restrict or enhance the expression of individual behaviour, and the recent social environment is thought to affect behavioural responses in later contexts, even when individuals are alone. However, little is known about how social dynamics influence the expression of individual physiological traits, including metabolic rates. There is some evidence that shoaling can reduce fish metabolic rates, but habitat conditions such as shelter availability may generate density-dependent influences on individual metabolic rates. We investigated how social group size and availability of shelter influence Eurasian minnow Phoxinus phoxinus metabolic rates estimated by respirometry in the presence or absence of plant shelter. Respirometry trials were conducted before and after we housed fish for three weeks in a social treatment consisting in a specific group size (n= 4 or 8) and shelter availability (presence or absence of plant shelter in the holding tank). Minimum day-time and night-time metabolic rates estimated while in presence of plant shelter were lower than when estimated in absence of plant shelter, both before and after individuals were housed in their social group size and shelter availability treatment. Standard metabolic rate was higher for fish held in groups of four as compared to fish held in groups of eight while maximum metabolic rate showed no difference. Shelter availability during the social treatments did not influence standard or maximum metabolic rates. Our results suggest that group size may directly influence energy demands of individuals, highlighting the importance of understanding the role of social dynamics on variations in physiological traits associated with energy expenditure.

Modeling shelter abundance for juvenile Atlantic salmon in a residual flow reach of a hydro power plant using SSIIM 2

<p>Nowadays, the aquatic biodiversity is highly under pressure due to anthropogenic changes of the rivers such hydraulic structures changing the diversity of flow and aquatic fauna as well as sediment continuity. This can have severe consequences on the fish population in the river reach. Fish are strongly depending on a certain substrate composition throughout all their life stages. Juveniles for example are depending on a certain availability of shelter in the substrate in order to survive this stage.</p><p>Therefore, we investigate the effects of changes in the sediment composition at a hydropower plant in Switzerland on the availability of potential shelter for juvenile fish. By utilizing the observed correlation between parameters describing the fine tail of a riverbed’s grain size distribution and shelter abundance for juvenile Atlantic salmon, we predict the available shelter in a river reach by using a 3D hydrodynamic numerical model directly coupled to a morphodynamic model. The initial substrate composition was assumed to be spatially uniform, its parameters based on a grain size distribution curve derived from collected sediment samples.</p><p>This model can now be used for habitat improvement scenario modeling. Based on the assumption that a specific mixture of sediment coming from upstream travelling through the river reach will positively influence the potential shelter availability, different scenarios can be investigated. The baseline for comparison was the simulation of the bed changes without any sediment supply from upstream. The baseline discharge was set to 100 m<sup>3</sup> /s and was applied for 24 hours. The resulting bed changes create a map of the potential shelter availability of this grain size mixture. Then, two scenarios with sediment inflow from the upstream boundary were simulated. One coarse and one fine mixture of sediment were chosen as inputs, with the goal of investigating their impact on shelter abundance. The former designed to have a positive effect while the latter expected to reduce interstitial voids in the substrate and have a negative effect on available shelter.</p><p>The investigation is conducted as part of the EU Horizon 2020 funded project FIThydro (funded under 727830)</p>

Linking changing grain size distributions with the development of shelter availability for fish in the bypass reach of a hydro power plant

<p>Nowadays, the aquatic biodiversity is highly under pressure due to anthropogenic changes<br>of rivers such hydraulic structures changing the diversity of flow and aquatic fauna as well<br>as sediment continuity. This can have severe consequences on the fish population in the<br>river reach. Fish are strongly depending on a certain substrate composition throughout all<br>their life stages. Juveniles e.g. are depending on a certain availability of shelter in the<br>substrate in order to survive this stage. Therefore we investigate the effects of changes in<br>the sediment composition at a Hydropower plant in Switzerland on the availability of<br>potential shelter for juvenile fish. The investigation is conducted as part of the EU Horizon<br>2020 funded project FIThydro (funded under 727830).<br>To reach this goal, we measured the sediment compositions at several locations in the<br>bypass reach with different measurement techniques such as sieving, photogrammetry<br>(Basegrain) and the pebble count method. Further we measured the shelter availability in<br>the corresponding locations, using the so called Finstad method. As the method was<br>developed purely for Atlantic salmon, we modified it by expanded the variability of<br>available sizes. The resulting correlation of the grain size distribution with the potential<br>shelter availability at different locations showed a fairly high correlation coefficient. This<br>equation can then be used in hydro-morphological models to estimate the spatial<br>distribution of potential shelter availability for any given flow regime and grain size<br>distribution. Further investigation at other sites will over time enlarge the database and<br>therefore improve the correlation.</p>

Factors Affecting Spitting Behavior on Betel Consumers in Applicating PHBS Public Places in Pasar Raya Simalungun Regency

This study discusses about factors affecting spitting behavior on betel consumers in applicating PHBS public places in Pasar Raya Simalungun Regency. This research is a descriptive study to describe factors affecting spitting behavior on betel consumers in applicating phbs public places. This research is conducted at Pasar Raya Simalungun Regency. The time for conducting the research starts from the beginning of November 2018 until completion. The result shows Respondents are more well-informed, namely 44 people (43%), more respondents with shelter availability of spit consuming betel, namely 55 people (63.2%). More respondents with poor health support, 68 people (78.2%).

Shelters can negatively affect growth and welfare in lumpfish if feed is delivered continuously

Due to the socioeconomic importance of salmon farming in the North Atlantic and the economic impact of sea lice in this industry, there is high demand for novel pest control methods. One such method is the use of cleaner fish to remove the lice from the salmon. A cleaner fish that has recently gained in popularity due to its ability to work in cold water, is the lumpfish (Cyclopterus lumpus). This fish varies in efficiency, but when mortality is low and cleaning optimal, the fish are successful in keeping parasite burdens low. However, there is some concern for the welfare of lumpfish in the industry, because mortality is often high. This is sometimes attributed to inadequate feeding and shelter. Here we compare growth, body condition, and fin health of fish reared for four weeks in a crossed treatment design crossing shelter availability (shelter vs none) and feed delivery method (manual meal time feeds and continuous automated feeding). In terms of weight gain, shelter availability interacted with feeding method, with fish that had access to shelters and were fed using automated feeders gaining less weight than other fish. Fin health was not affected, but body condition was lowered both by access to shelter and being fed continuously. The results indicate a need to carefully consider how feeding method and shelter use is combined, both in cages and during rearing on land.

Spatiotemporal dynamics in caddisfly (Insecta: Trichoptera) of a Cerrado stream, Brazil

Knowing the patterns and mechanisms that regulate spatiotemporal dynamics in aquatic communities is a great challenge. Theoretically, the distribution of aquatic insects is related to food and shelter availability, and/or to dispersal. In this perspective, we analyzed the spatiotemporal variation of Trichoptera communities of a Cerrado stream for 3 years. The longitudinal and temporal distribution provided a good explanation of the variation of the Trichoptera species composition. Specifically, 21.4 and 11.5% of the variation in composition was explained by longitudinal and temporal variation, respectively, and 8.3% by the interaction of both factors. The variation of environmental conditions (pH, total dissolved solids and dissolved oxygen) and temporal autocorrelation were the most important predictors for the distribution of Trichoptera communities. Accordingly, it is possible to assume that seasonal variation throughout the year is also an important factor for this aquatic community, in addition to water quality, as is widely known. Therefore, climate change should affect both temporal and spatial patterns of Trichoptera communities present in Cerrado streams. Consequently, such effect should be expected to occur in other regions with more marked seasons.