Multi-specific effects of increasing T90 mesh size and amount in an Australian fish trawl

Increases in the size and amount of meshes turned 90° ('T90') in an Australian fish-trawl codend were investigated to improve the size selection of deepwater flathead Neoplatycephalus conatus and reduce discards. The conventional codend comprised 94-mm mesh throughout with normal orientation (diamond-shaped) in the posterior half but T90 in the anterior half ('half 94-mm T90' codend). Two new codends had 105-mm T90 mesh in the anterior section only ('half 105-mm T90') and throughout ('full 105-mm T90'). Both larger-meshed codends caught fewer immature deepwater flathead, but also lost some larger fish, especially the full 105-mm T90 codend, which had 80% more T90 meshes. The larger-meshed codends also allowed some discarded species to escape, but similarly affected other targets. Collected deepwater flathead morphological data support a T90 mesh size of ~100 mm in the anterior codend or ~94 mm throughout to maintain target sizes. However, irrespective of changes to codend meshes, owing to comparable inter-specific sizes and shapes, the discard percentage in this fishery will probably remain consistent at >75%, which is more than double the global average for fish trawls. Future efforts to improve selection in the fishery should consider modifications other than codend changes

Reproduction of blacknose shark (Carcharhinus acronotus) in coastal waters off northeastern Brazil

The blacknose shark, Carcharhinus acronotus, is a relatively small carcharinid, typically inhabiting continental shelf areas in the western Atlantic Ocean, from North Carolina throughout the Gulf of Mexico (Bigelow and Schroeder, 1948) and along the South American coast to Rio de Janeiro (Compagno, 1984). The abundance of this shark in nearshore areas throughout its distribution makes it accessible to commercial fishing, mainly from inshore hook-and-line and gill-net fisheries (Trent et al., 1997; Mattos and Hazin1)

Reducing the marine debris of recreational hoop nets in south-eastern Australia

Alternative configurations of Australian recreational portunid hoop nets were investigated to address debris and selectivity issues. Four treatment nets (all comprising 152-mm polyamide–PA mesh) were assessed that differed in their twine (conventional multifilament vs new multi-monofilament) and fishing configuration (conventional conical vs inverted shapes). The conical multifilament design lost means (±\ua0SEs) of 130.6\ua0±\ua023.1 and 5.3\ua0±\ua01.2\ua0mm of twine 3-h soak when used to target Scylla serrata and Portunus pelagicus. Inverting this hoop net significantly reduced legal-sized catches (by up to 70%) and with greater twine loss (×\ua05) when targeting P. pelagicus. Conversely, both multi-monofilament configurations maintained legal catches of S. serrata and P. pelagicus, but lost 78 and 95% less twine than the conical multifilament design. Using multi-monofilament hoop nets could reduce PA debris by thousands of m p.a. in south-eastern Australia, without affecting targeted catches. Further, a lower fishing height of inverted multi-monofilament nets might reduce non-portunid bycatch

Experiments in gear configuration to reduce bycatch in an estuarine squid-trawl fishery

Three experiments were performed in an estuarine squid-trawl fishery in New South Wales, Australia, to test modifications to trawl nets. Lateral mesh openings were experimentally increased and physical bycatch reduction devices (BRDs) were placed in codends. These modifications aimed to reduce nontargeted catches of fish, while maintaining catches of the targeted broad squid (Photololigo etheridgei) and bottle squid (Loliolus noctiluca). Compared to conventional codends made with 41-mm diamond mesh, codends made with different posterior circumferences and larger 45-mm mesh had no significant effect on the catches of any species. The best performing configurations involved the installation of BRDs designed to separate organisms according to differences in behavior. In particular, versions of a composite square-mesh panel reduced the total weight of bycatch by up to 71% and there was no significant effect on the catches of squid. The results are discussed in terms of the probable differences in behavior between fish and squid in codends. After this study, a square-mesh panel BRD was voluntarily adopted throughout the fishery

Refining a Nordmøre-grid bycatch reduction device for the Spencer Gulf penaeid-trawl fishery

Incremental refinements were made to a generic Nordmøre-grid to minimise bycatches of blue swimmer crabs Portunus armatus and giant cuttlefish Sepia apama, while maintaining catches of western king prawns Melicertus latisulcatus in the Spencer Gulf penaeid-trawl fishery. These refinements involved varying bar spaces, escape-exit areas and guiding-panel lengths, and were compared against a conventional trawl. Catches of teleosts and M. latisulcatus largely remained unaffected by the changes. Maximum reductions in P. armatus and S. apama bycatches (both ~90%) were achieved with a Nordmøre-grid comprising 38-mm bar spaces, 0.81- or 1.05-m2 escape exits and a 2.7-m guiding panel. Catching fewer P. armatus should reduce abrasion and crushing of M. latisulcatus in the codend and so increase the value of this targeted species. While noting some unresolved operational concerns, these results demonstrate the potential improvements in selectivity in this fishery using a Nordmøre-grid, primarily by mechanical separation

A SARS-CoV-2 protein interaction map reveals targets for drug repurposing

The novel coronavirus SARS-CoV-2, the causative agent of COVID-19 respiratory disease, has infected over 2.3 million people, killed over 160,000, and caused worldwide social and economic disruption1,2. There are currently no antiviral drugs with proven clinical efficacy, nor are there vaccines for its prevention, and these efforts are hampered by limited knowledge of the molecular details of SARS-CoV-2 infection. To address this, we cloned, tagged and expressed 26 of the 29 SARS-CoV-2 proteins in human cells and identified the human proteins physically associated with each using affinity-purification mass spectrometry (AP-MS), identifying 332 high-confidence SARS-CoV-2-human protein-protein interactions (PPIs). Among these, we identify 66 druggable human proteins or host factors targeted by 69 compounds (29 FDA-approved drugs, 12 drugs in clinical trials, and 28 preclinical compounds). Screening a subset of these in multiple viral assays identified two sets of pharmacological agents that displayed antiviral activity: inhibitors of mRNA translation and predicted regulators of the Sigma1 and Sigma2 receptors. Further studies of these host factor targeting agents, including their combination with drugs that directly target viral enzymes, could lead to a therapeutic regimen to treat COVID-19

Improving penaeid-trawl efficiencies via ground gear with tickler chains

Penaeid trawls often have poor ecological efficiencies measured as unwanted bycatches (with high discard mortality) an

Influences of type and orientation of bait on catches of swordfish (Xiphias gladius) and other species in an artisanal sub-surface longline fishery off northeastern Brazil

Two experiments were done to examine the relative effectiveness of squid and mackerel as bait for artisanal longliners operating off the northeast coast of Brazil. In experiment 1, compared to clusters of hooks baited with vertically orientated squid, those with vertically orientated mackerel (attached to hooks according to normal commercial operations) showed significantly more contact by fish and had less bait remaining at the end of each set, but retained significantly less total fish by weight and fewer swordfish. Significantly more swordfish swallowed hooks baited with vertically orientated squid, than those with vertically orientated mackerel and showed greater mortality. In experiment 2, clusters of hooks baited with horizontally orientated mackerel had significantly greater contact by fish and less bait remaining than those baited with vertically orientated squid. No other significant differences were detected between baits. Type of bait showed no significant effect on anatomical hook location and mortality for total catch (all species combined) and swordfish. The results are discussed in terms of possible factors influencing behaviour of fish during the hooking process and the importance of the visual stimuli of baits for subsurface longlines