Intraspecific Variation in Vertical Habitat Use by Tiger Sharks (Galeocerdo cuvier) in the Western North Atlantic

Tiger sharks (Galeocerdo cuvier) are a wide ranging, potentially keystone predator species that display a variety of horizontal movement patterns, making use of coastal and pelagic waters. Far less, however, is known about their vertical movements and use of the water column. We used pop-up satellite archival tags with two data sampling rates (high rate and standard rate tags) to investigate the vertical habitat use and diving behavior of tiger sharks tagged on the Puerto Rico–Virgin Islands platform and off Bermuda between 2008 and 2009. Useable data were received from nine of 14 sharks tagged, tracked over a total of 529 days. Sharks spent the majority of their time making yo-yo dives within the upper 50 m of the water column and considerable time within the upper 5 m of the water column. As a result, sharks typically occupied a narrow daily temperature range (~2°C). Dives to greater than 200 m were common, and all sharks made dives to at least 250 m, with one shark reaching a depth of 828 m. Despite some similarities among individuals, a great deal of intraspecific variability in vertical habit use was observed. Four distinct depth distributions that were not related to tagging location, horizontal movements, sex, or size were detected. In addition, similar depth distributions did not necessitate similar dive patterns among sharks. Recognition of intraspecific variability in habitat use of top predators can be crucial for effective management of these species and for understanding their influence on ecosystem dynamics

First insights into the vertical habitat use of the whitespotted eagle ray Aetobatus narinari revealed by pop‐up satellite archival tags

The whitespotted eagle ray Aetobatus narinari is a tropical to warm‐temperate benthopelagic batoid that ranges widely throughout the western Atlantic Ocean. Despite conservation concerns for the species, its vertical habitat use and diving behaviour remain unknown. Patterns and drivers in the depth distribution of A. narinari were investigated at two separate locations, the western North Atlantic (Islands of Bermuda) and the eastern Gulf of Mexico (Sarasota, Florida, U.S.A.). Between 2010 and 2014, seven pop‐up satellite archival tags were attached to A. narinari using three methods: a through‐tail suture, an external tail‐band and through‐wing attachment. Retention time ranged from 0 to 180 days, with tags attached via the through‐tail method retained longest. Tagged rays spent the majority of time (82.85 ± 12.17% S.D.) within the upper 10 m of the water column and, with one exception, no rays travelled deeper than ~26 m. One Bermuda ray recorded a maximum depth of 50.5 m, suggesting that these animals make excursions off the fore‐reef slope of the Bermuda Platform. Individuals occupied deeper depths (7.42 ± 3.99 m S.D.) during the day versus night (4.90 ± 2.89 m S.D.), which may be explained by foraging and/or predator avoidance. Each individual experienced a significant difference in depth and temperature distributions over the diel cycle. There was evidence that mean hourly depth was best described by location and individual variation using a generalized additive mixed model approach. This is the first study to compare depth distributions of A. narinari from different locations and describe the thermal habitat for this species. Our study highlights the importance of region in describing A. narinari depth use, which may be relevant when developing management plans, whilst demonstrating that diel patterns appear to hold across individuals

Nanoscale Mechanical Characterisation of Amyloid Fibrils Discovered in a Natural Adhesive

Using the atomic force microscope, we have investigated the nanoscale mechanical response of the attachment adhesive of the terrestrial alga Prasiola linearis (Prasiolales, Chlorophyta). We were able to locate and extend highly ordered mechanical structures directly from the natural adhesive matrix of the living plant. The in vivo mechanical response of the structured biopolymer often displayed the repetitive sawtooth force-extension characteristics of a material exhibiting high mechanical strength at the molecular level. Mechanical and histological evidence leads us to propose a mechanism for mechanical strength in our sample based on amyloid fibrils. These proteinaceous, pleated β-sheet complexes are usually associated with neurodegenerative diseases. However, we now conclude that the amyloid protein quaternary structures detected in our material should be considered as a possible generic mechanism for mechanical strength in natural adhesives

An Assessment of Mobile Predator Populations along Shallow and Mesophotic Depth Gradients in the Hawaiian Archipelago.

Large-bodied coral reef roving predators (sharks, jacks, snappers) are largely considered to be depleted around human population centers. In the Hawaiian Archipelago, supporting evidence is primarily derived from underwater visual censuses in shallow waters (=30?m). However, while many roving predators are present or potentially more abundant in deeper strata (30-100?m+), distributional information remains sparse. To partially fill that knowledge gap, we conducted surveys in the remote Northwestern Hawaiian Islands (NWHI) and populated Main Hawaiian Islands (MHI) from 2012-2014 using baited remote underwater stereo-video. Surveys between 0-100?m found considerable roving predator community dissimilarities between regions, marked conspicuous changes in species abundances with increasing depth, and largely corroborated patterns documented during shallow water underwater visual censuses, with up to an order of magnitude more jacks and five times more sharks sampled in the NWHI compared to the MHI. Additionally, several species were significantly more abundant and larger in mesophotic versus shallow depths, which remains particularly suggestive of deep-water refugia effects in the MHI. Stereo-video extends the depth range of current roving predator surveys in a more robust manner than was previously available, and appears to be well-suited for large-scale roving predator work in the Hawaiian Archipelago

On the edge: Chaucer and Gower’s queer glosses

In this article Diane Watt and I focus on a number of manuscript glosses accompanying the tale of Constance in Chaucer's The Man of Law's Tale and in Gower's Tale of Constance in Confessio Amantis. By applying queer theory to the paratextual apparatus of these manuscripts, we shed new light on the anxieties about authority and authorship shared by Chaucer and Gower (and their circles of collaborators). We also reevaluate the role of error and manuscripts variants, and argue for the queer pleasure provided by misprision and misinterpretation. This helps us to move away from patriarchal constructs on canon formation and manuscript transmission

A recurrent 16p12.1 microdeletion supports a two-hit model for severe developmental delay.

We report the identification of a recurrent, 520-kb 16p12.1 microdeletion associated with childhood developmental delay. The microdeletion was detected in 20 of 11,873 cases compared with 2 of 8,540 controls (P = 0.0009, OR = 7.2) and replicated in a second series of 22 of 9,254 cases compared with 6 of 6,299 controls (P = 0.028, OR = 2.5). Most deletions were inherited, with carrier parents likely to manifest neuropsychiatric phenotypes compared to non-carrier parents (P = 0.037, OR = 6). Probands were more likely to carry an additional large copy-number variant when compared to matched controls (10 of 42 cases, P = 5.7 x 10(-5), OR = 6.6). The clinical features of individuals with two mutations were distinct from and/or more severe than those of individuals carrying only the co-occurring mutation. Our data support a two-hit model in which the 16p12.1 microdeletion both predisposes to neuropsychiatric phenotypes as a single event and exacerbates neurodevelopmental phenotypes in association with other large deletions or duplications. Analysis of other microdeletions with variable expressivity indicates that this two-hit model might be more generally applicable to neuropsychiatric disease