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

Colorectal cancer incidences in Lynch syndrome: a comparison of results from the prospective lynch syndrome database and the international mismatch repair consortium

Objective To compare colorectal cancer (CRC) incidences in carriers of pathogenic variants of the MMR genes in the PLSD and IMRC cohorts, of which only the former included mandatory colonoscopy surveillance for all participants. Methods CRC incidences were calculated in an intervention group comprising a cohort of confirmed carriers of pathogenic or likely pathogenic variants in mismatch repair genes (path_MMR) followed prospectively by the Prospective Lynch Syndrome Database (PLSD). All had colonoscopy surveillance, with polypectomy when polyps were identified. Comparison was made with a retrospective cohort reported by the International Mismatch Repair Consortium (IMRC). This comprised confirmed and inferred path_MMR carriers who were first- or second-degree relatives of Lynch syndrome probands. Results In the PLSD, 8,153 subjects had follow-up colonoscopy surveillance for a total of 67,604 years and 578 carriers had CRC diagnosed. Average cumulative incidences of CRC in path_MLH1 carriers at 70 years of age were 52% in males and 41% in females; for path_MSH2 50% and 39%; for path_MSH6 13% and 17% and for path_PMS2 11% and 8%. In contrast, in the IMRC cohort, corresponding cumulative incidences were 40% and 27%; 34% and 23%; 16% and 8% and 7% and 6%. Comparing just the European carriers in the two series gave similar findings. Numbers in the PLSD series did not allow comparisons of carriers from other continents separately. Cumulative incidences at 25 years were < 1% in all retrospective groups. Conclusions Prospectively observed CRC incidences (PLSD) in path_MLH1 and path_MSH2 carriers undergoing colonoscopy surveillance and polypectomy were higher than in the retrospective (IMRC) series, and were not reduced in path_MSH6 carriers. These findings were the opposite to those expected. CRC point incidence before 50 years of age was reduced in path_PMS2 carriers subjected to colonoscopy, but not significantly so

Post-Operative Functional Outcomes in Early Age Onset Rectal Cancer

Background: Impairment of bowel, urogenital and fertility-related function in patients treated for rectal cancer is common. While the rate of rectal cancer in the young (&lt;50 years) is rising, there is little data on functional outcomes in this group. Methods: The REACCT international collaborative database was reviewed and data on eligible patients analysed. Inclusion criteria comprised patients with a histologically confirmed rectal cancer, &lt;50 years of age at time of diagnosis and with documented follow-up including functional outcomes. Results: A total of 1428 (n=1428) patients met the eligibility criteria and were included in the final analysis. Metastatic disease was present at diagnosis in 13%. Of these, 40% received neoadjuvant therapy and 50% adjuvant chemotherapy. The incidence of post-operative major morbidity was 10%. A defunctioning stoma was placed for 621 patients (43%); 534 of these proceeded to elective restoration of bowel continuity. The median follow-up time was 42 months. Of this cohort, a total of 415 (29%) reported persistent impairment of functional outcomes, the most frequent of which was bowel dysfunction (16%), followed by bladder dysfunction (7%), sexual dysfunction (4.5%) and infertility (1%). Conclusion: A substantial proportion of patients with early-onset rectal cancer who undergo surgery report persistent impairment of functional status. Patients should be involved in the discussion regarding their treatment options and potential impact on quality of life. Functional outcomes should be routinely recorded as part of follow up alongside oncological parameters

The composite square-mesh panel: A modification to codends for reducing unwanted bycatch and increasing catches of prawns throughout the New South Wales oceanic prawn-trawl fishery

The effectiveness of a new bycatch reduction device (BRD) was tested across a wide geographical range to determine its use in the NSW oceanic prawn-trawl fishery. Using four commercial trawlers, each from a different port located in the fishery, we compared the catches and bycatches from conventional trawls with those from trawls containing composite panels of netting (60 mm and 40 mm) hung on the bar and inserted into the top anterior section of the codend (termed the composite-panel codend). This panel was designed so that the 40-mm mesh 1) would allow some small fish to escape and 2) would distribute the load anterior and lateral to the 60-mm mesh (which was located in an area where waterflow was thought to be greatest), allowing the 60-mm mesh to remain open and thus facilitate the removal of larger fish. Simultaneous comparisons against a control codend showed that the composite-panel codend significantly reduced the weights of discarded bycatch at all four locations (means reduced by 23.5% to 41%) and the numbers of juveniles of commercially important species, such as whiting, Sillago sp. (by up to 70%). At three of the locations the composite-panel significantly increased the catches of the prawn Penaeus plebejus (5.5% to 14%) and, although not statistically significant, showed a similar trend at the fourth location (mean increase of 4%). As a result of this study, the composite-panel codend has been adopted and voluntarily used by fishermen throughout the New South Wales oceanic prawn-trawl fishery

By-catch begone: Changes in the philosophy of fishing technology

Since humans began fishing (at least 90 000 years ago). fishing technology has developed with the objective of trying to catch the greatest quantities of fish possible. of an ever-increasing variety. Fishing technology has evolved from simple harpoons and hooks to the industrial factory trawlers of the 20th century. After millennia of assuming that seafood resources are inexhaustible, and centuries of somewhat muted concerns that advanced fishing technologies may have detrimental impacts on stocks and ecosystems, the last century has seen advances in fishing technology blamed as a major cause of the current over-exploitation of fish stocks. It has mainly been during the last few decades that fishing technologies have begun to focus on more conservation-orientated goals. This occurred initially in response to concerns over the by-catch of charismatic species (like dolphins in tuna purse-seines), but quickly broadened to address concerns over the discarding of not-so-charismatic species (like juvenile fish killed by shrimp trawling). To ameliorate these issues, technologists and commercial fishers successfully developed various innovative gear-based and operational solutions. The steps involved in successfully reducing by-catches have tended to follow a certain incremental framework involving identification of problems using observer programmes, developing technological solution to these problems, experimentally testing these solutions, implementing these solutions throughout industry and finally gaining acceptance of the solutions from concerned interest groups. Most recently public concern has broadened once again from by-catch issues to encompass a much wider context involving the impacts of fishing on entire ecosystems, i.e. the impacts of fishing on all species affected - not just those species caught, retained or discarded. As a consequence, there have been many calls for ecosystem-based fisheries management to ensure that fisheries operate under the principles of ecologically sustainable development. Scientists are gradually filling the gaps in our knowledge about how fishing affects whole ecosystems but, because of the scales and complexities involved, such studies are usually difficult, expensive and of long duration. While this descriptive work is difficult, finding solutions to any identified problem is an even greater challenge, particularly for fishing technologists. The easiest solutions to such problems involve rather draconian management strategies like closures. A less extreme alternative involves the development of new technologies that reduce the impacts of fishing on ecosystems -in a similar way as that done to reduce by-catch problems. Innovations like altering ground-chains, footropes, sweeps and trawl doors have been suggested as possible ways to ameliorate the environmental damage done by trawling, but such research is still very much in its infancy. Nevertheless, the recent history of fishing technology is chequered with successfully meeting such challenges, giving one confidence that solutions to such issues may eventually be developed. Integral to the success of any solutions that strive towards the goal of perfect selectivity, however, is a corresponding improvement in the adoption of these methods by fishers. As our framework shows, this is best achieved by involving fishers in all aspects of the work

Mitigating the bycatch of giant cuttlefish Sepia apama and blue swimmer crabs Portunus armatus in an Australian penaeid-trawl fishery

Trawlers in Spencer Gulf, Australia, target western king prawns Melicertus latisulcatus, with nearly all other species discarded; two of the latter have evoked significant, although quite different, concerns. The first is the giant cuttlefish Sepia apama, which has undergone a drastic decline in numbers in Spencer Gulf in recent years, and is listed as 'Near Threatened' by the International Union for the Conservation of Nature. S. apama are susceptible to trawling during their annual spawning migration through Spencer Gulf. The other bycatch problem involves large quantities of blue swimmer crabs Portunus armatus, which currently are separated inside the trawl using a large-meshed liner. Due to the additional handling required and the physical damage caused by the crabs' exoskeletons on the soft-bodied M. latisulcatus and Sepia spp., P. armatus would ideally be able to escape of their own accord during towing. This study examined the utility of mechanical-separating bycatch reduction devices (BRDs) for reducing unwanted bycatches of Sepia spp. and P. armatus. We compared (against conventional codends) the smallest and largest practical sizes of Nordmøre-grids (the latter to maximise sorting area), with correspondingly large and low grid angles. The large Nordmøre-grid significantly reduced Sepia spp., P. armatus and total bycatch (by 33-50%), but had no effect on catches of M. latisulcatus. Whilst additional research is required, a modified Nordmøre-grid should help to resolve the bycatch of P. armatus and S. apama in this fishery, with minimal commercial impacts

Effects of square-mesh panels in codends and of haulback delay on bycatch reduction in the oceanic prawn-trawl fishery of New South Wales, Australia

Two experiments were conducted in the New South Wales oceanic prawn- trawl fishery, 1) by comparing catch from a conventional codend with that from two new codend designs with square-mesh panels and 2) by showing the effects on catches of a short delay in haulback of trawls with squaremesh panels. The two new codend designs incorporated panels of netting (85-mm mesh) sewn such that the meshes were square-shaped (measuring 7 x 11 bars) and inserted lengthwise and widthwise into the tops of the anterior sections. Simultaneous comparisons among these designs and a conventional codend showed that both designs performed similarly by significantly reducing the weights of bycatch that would be discarded (by 46% and 38%, respectively) without significantly reducing the catch of the prawn Penaeus plebejus. The second experiment showed that juvenile red spot whiting, Sillago flindersi, an important commercial finfish, escaped from the square- mesh panels in the trawl during a 10-15 second haulback delay. Trawls without any haulback delay showed no significant reduction in the bycatch of this species. The results are discussed in terms of the probable behavior of fish in the modified trawls and in terms of the implications that factors such as haulback delay may have on the survival of fish escaping through square-mesh panels in codends

The European Landing Obligation. Reducing Discards in Complex, Multi-Species and Multi-Jurisdictional Fisheries

This open access book provides a comprehensive examination of the European Landing Obligation policy from many relevant perspectives. It includes evaluations of its impacts at economical, socio-cultural, ecological and institutional levels. It also discusses the feasibility and benefits of several potential mitigation strategies. The book was timely published, exactly at the time where the Landing Obligation was planned to be fully implemented. This book is of significant interest to all stakeholders involved, but also to the general public of Europe and to other jurisdictions throughout the world that are also searching for ways to deal with by-catch and discard issues