Spatial behavior, swimming speed and surfacing rate of two captive harbor porpoises in ambient sound control conditions

Foraging is made up of three steps: first, to search and encounter a suitable foraging patch; next prey has to be found, and finally the prey has to be caught and eaten. Behavioral responses to anthropogenic noise may lead to a disruption of vital activities within this process, such as area avoidance, or reduced abilities to locate or catch prey. Gaining insight into these behavioral effects starts with a thorough understanding of within- and between-individual variation in the baseline behavior of experimental conditions. In this study, we analyzed control trials for two captive harbor porpoises that were tested for spatial behavior in a set-up for experimental sound exposure. Data from trials without any experimental sound exposure were used to investigate relationships between the response variable - time spent away from the preferred area - and two other behavioral metrics: swimming speed and surfacing rate. The results show that these metrics can be used as independent measures, the first being correlated to the response variable, the second uncorrelated. Combining the two makes a better and more complete judgment. Performing an adequate exploration of the variation in behavior during control trials is important, as it will aid scientists in revealing and interpreting effects of disturbance in sound exposure trials.Animal science

Characterization of a sponge microbiome using an integrative genome-centric approach

Marine sponges often host diverse and species-specific communities of microorganisms that are critical for host health. Previous functional genomic investigations of the sponge microbiome have focused primarily on specific symbiont lineages, which frequently make up only a small fraction of the overall community. Here, we undertook genome-centric analysis of the symbiont community in the model species Ircinia ramosa and analyzed 259 unique, high-quality metagenome-assembled genomes (MAGs) that comprised 74% of the I. ramosa microbiome. Addition of these MAGs to genome trees containing all publicly available microbial sponge symbionts increased phylogenetic diversity by 32% within the archaea and 41% within the bacteria. Metabolic reconstruction of the MAGs showed extensive redundancy across taxa for pathways involved in carbon fixation, B-vitamin synthesis, taurine metabolism, sulfite oxidation, and most steps of nitrogen metabolism. Through the acquisition of all major taxa present within the I. ramosa microbiome, we were able to analyze the functional potential of a sponge-associated microbial community in unprecedented detail. Critical functions, such as carbon fixation, which had previously only been assigned to a restricted set of sponge-associated organisms, were actually spread across diverse symbiont taxa, whereas other essential pathways, such as ammonia oxidation, were confined to specific keystone taxa

Preventie van wiegendood op maat

Uit de TNO-peiling van 2003 naar verzorgingsfactoren van zuigelingen blijkt dat de prevalentie van risicovolle verzorgingsfactoren laag is. Om preventie van wiegendood nog meer op maat te maken, is onder­ zocht of er associaties bestaan tussen deze erkende aan wiegendood gerelateerde verzorgingsfactoren (slaapligging, beddengoed , slaapplaats, passief roken en melkvoeding) en kenmerken van ouders. Hieruit blijkt dat vooral alleenstaande en/of werkloze moeders en ouders die niet in Nederland geboren zijn de adviezen ter preventie van wiegendood minder accuraat opvolgen. Met deze informatie kan de preventie gerichter worden gegeven aan specifieke ouders die kennis over deze verzorgingsfactoren mogelijk ontberen. De gebruikelijke preventie­ adviezen die via de verloskunde, de kraamzorg en de jeugdgezond­ heidszorg aan alle (aanstaande) ouders wordt aangeboden, moet niettemin onverminderd voortgang vinden

Spatial avoidance to experimental increase of intermittent and continuous sound in two captive harbour porpoises

The continuing rise in underwater sound levels in the oceans leads to disturbance of marine life. It isthought that one of the main impacts of sound exposure is the alteration of foraging behaviour of marinespecies, for example by deterring animals from a prey location, or by distracting them while they aretrying to catch prey. So far, only limited knowledge is available on both mechanisms in the same species.The harbour porpoise (Phocoena phocoena) is a relatively small marine mammal that could quickly sufferfitness consequences from a reduction of foraging success. To investigate effects of anthropogenic soundon their foraging efficiency, we tested whether experimentally elevated sound levels would deter twocaptive harbour porpoises from a noisy pool into a quiet pool (Experiment 1) and reduce their preysearchperformance, measured as prey-search time in the noisy pool (Experiment 2). Furthermore, wetested the influence of the temporal structure and amplitude of the sound on the avoidance response ofboth animals. Both individuals avoided the pool with elevated sound levels, but they did not show achange in search time for prey when trying to find a fish hidden in one of three cages. The combination oftemporal structure and SPL caused variable patterns. When the sound was intermittent, increased SPLcaused increased avoidance times. When the sound was continuous, avoidance was equal for all SPLsabove a threshold of 100 dB re 1 mPa. Hence, we found no evidence for an effect of sound exposure onsearch efficiency, but sounds of different temporal patterns did cause spatial avoidance with distinctdose-response patterns.Animal science