A brief introduction to the TrawledSeas Project: Bottom Trawling as a Driver of Seascape Transformation

5th International Network for Submarine Canyon Investigation and Scientific Exchange International Symposium (INCISE), 14-18 June 2021Bottom trawling is one of the most widespread fishing practices in the world’s oceans. It involves towing of nets to harvest benthic and demersal living resources. The dragging of trawling gears along the seafloor results in scraping and ploughing the seabed, which leads to the formation of turbid plumes of resuspended sediments, changes in the sediment erosion/accumulation rates and modifications of their fluxes and budgets, which results in measurable alterations of the submarine geomorphology. As submarine canyons are increasingly targeted by trawlers, there is a growing need to quantify, monitor and mitigate the impacts of bottom trawling in these environments. The TrawledSeas Project aims to quantitatively characterise the contribution of bottom trawling on the geomorphic evolution of submarine canyons, over a range of spatial scales, from fine (m–dam) to mesoscale (5–100 km). To address this objective, a new automated marine landscape mapping technique is being developed to quantify the morphological signature of bottom trawling, based on the analysis of high-resolution multibeam data implemented in a Geographic Information System (GIS). The proposed methodology integrates standard general (e.g. curvature, rugosity, roughness or fractal dimension) and specific (e.g. object-based image methods) geomorphic techniques with new ones developed in this project in a multiscale approach. It combines GIS open source tools with bathymetric dataset at different resolutions, from hull-mounted multibeam data to compare the large-scale morphology of trawled and untrawled areas, to Remotely Operated Vehicles (ROV) and autonomous underwater vehicle (AUV) bathymetric data to identify and quantify trawl marks at small spatial scale. Additionally, data from repeated surveys will be used to assess potential temporal changes in the seafloor morphology of new fishing grounds. The implementation of these geomorphological tools in different study sites incised by submarine canyons (e.g. Catalan, Malta-Sicilian, Norwegian, Canterbury, Patagonian and W Canadian continental margins), will allow to characterise the differential impact of bottom trawling on the canyons’ seafloor, in terms of extent, rates and volume change in different geologic and climatic settingsPeer reviewe

Local support for conservation is associated with perceptions of good governance, social impacts, and ecological effectiveness

Local support is important for the longevity of conservation initiatives. The literature suggests that perceptions of ecological effectiveness, social impacts, and good gov- ernance will influence levels of local support for conservation. This paper examines these relationships using data from a survey of small-scale fishermen in 11 marine pro- tected areas from six countries in the Mediterranean Sea. The survey queried small- scale fishermen regarding perceptions and support for conservation. We constructed composite scores for three categories of perceptions—ecological effectiveness, social impacts, and good governance—and tested the relationship with levels of support using ordinal regression models. While all three factors were positively correlated with support for conservation, perceptions of good governance and social impacts were stronger predictors of increasing support. These findings suggest that employ- ing good governance processes and managing social impacts may be more important than ecological effectiveness for maintaining local support for conservation

Local support for conservation is associated with perceptions of good governance, social impacts, and ecological effectiveness

Local support is important for the longevity of conservation initiatives. The literature suggests that perceptions of ecological effectiveness, social impacts, and good governance will influence levels of local support for conservation. This paper examines these relationships using data from a survey of small-scale fishermen in 11 marine protected areas from six countries in the Mediterranean Sea. The survey queried small-scale fishermen regarding perceptions and support for conservation. We constructed composite scores for three categories of perceptions-ecological effectiveness, social impacts, and good governance-and tested the relationship with levels of support using ordinal regression models. While all three factors were positively correlated with support for conservation, perceptions of good governance and social impacts were stronger predictors of increasing support. These findings suggest that employing good governance processes and managing social impacts may be more important than ecological effectiveness for maintaining local support for conservation

The potential of marginal coastal nursery habitats for the conservation of a culturally important Caribbean marine species

Aim: Identifying the potential of marginal habitats for species conservation is of key importance when their core high-quality habitats are under substantial disturbances and threats. However, there is currently a knowledge gap on how useful marine marginal habitats may be for conserving endangered marine species. Here, we investigate the potential of groundwater-fed coastal areas for the conservation of the queen conch, an economically and culturally important marine gastropod. Location: The inlet of Xel-Ha, typical of groundwater-fed coastal areas widely distributed along the Yucatan Peninsula coast in Mexico and partially protected by a network of marine protected areas. Methods: We tracked 66 queen conchs (Lobatus gigas) using acoustic telemetry over a period of 3.5 years. We investigated for ontogenetic niche shift using a network analysis and by modelling their growth. Results: The queen conchs exhibited the same ontogenetic niche shift required to complete their life cycle in this marginal habitat as they do in offshore core habitats. A total of 33 individuals departed the inlet and migrated from shallow groundwater-affected nursery grounds to deeper marine habitats more suitable for breeding aggregation. Main conclusions: As the broad-scale movement behaviour of queen conch in this inlet is similar to that observed on the overfished core habitats, our findings suggest that groundwater-fed coastal areas should be included in conservation planning for an effective management of this species within a network of marine protected areas

Connectivity, neutral theories and the assessment of species vulnerability to global change in temperate estuaries

One of the main adaptation strategies to global change scenarios, aiming to preserve ecosystem functioning and biodiversity, is to maximise ecosystem resilience. The resilience of a species metapopulation can be improved by facilitating connectivity between local populations, which will prevent demographic stochasticity and inbreeding. The objective of this investigation is to estimate the degree of connectivity among estuarine species along the north-eastern Iberian coast, in order to assess community vulnerability to global change scenarios. To address this objective, two connectivity proxy types have been used based upon genetic and ecological drift processes: 1) DNA markers for the bivalve cockle (Cerastoderma edule) and seagrass Zostera noltei, and 2) the decrease in the number of species shared between two sites with geographic distance; neutral biodiversity theory predicts that dispersal limitation modulates this decrease, and this has been explored in estuarine plants and macroinvertebrates. Results indicate dispersal limitation for both saltmarsh plants and seagrass beds community and Z. noltei populations; this suggests they are especially vulnerable to expected climate changes on their habitats. In contrast, unstructured spatial pattern found in macroinvertebrate communities and in C. edule genetic populations in the area suggests that estuarine soft-bottom macroinvertebrates with planktonic larval dispersal strategies may have a high resilience capacity to moderate changes within their habitats. Our findings can help environmental managers to prioritise the most vulnerable species and habitats to be restored

The Voice, June 1983: Volume 29, Issue 5

Dordt\u27s Graduation Ceremonies Held May 6; Archives Preserves the Dutch Heritage; Reflections on Graduation; Canadian Group Tours Dordt College; Ag Day Attracts Community and Campus People; Students Compete in Writing Contest; Ministers Conference Focuses on the Church\u27s Task; Over 400 Attend Subscribers Banquet; Music Festival Attracts Large Numbers; Van Dyk Publishes Paper; Dordt Faculty to Participate in Summer Workshops; Schaap, Stair and Ward Write Musical; Newsbriefshttps://digitalcollections.dordt.edu/dordt_voice/1259/thumbnail.jp

The Voice, June 1982: Volume 28, Issue 5

Hollaar and De Groot Retire from Dordt; \u27Precious Heritage, Promising Future\u27 Highlights Anniversary Celebration; Farewell!; Dordt Expresses a Need for Nurses; Dairy Open Houses Attract Many People; Dordt Awards 241 Degrees May 7; Faculty Members Accept New Positions Elsewhere; Ag Center Presented at ISU Symposium; Dordt Offers Summer Courses in P. E. and Music; Studies Institute Presents Lectures; Defender Baseball Season Ends with Substate Tournament; Women\u27s Softball Team Ends Season; Vander Berg Named Athletic Director; Newsbriefshttps://digitalcollections.dordt.edu/dordt_voice/1265/thumbnail.jp

A hierarchical approach to defining marine heatwaves

Marine heatwaves (MHWs) have been observed around the world and are expected to increase in intensity and frequency under anthropogenic climate change. A variety of impacts have been associated with these anomalous events, including shifts in species ranges, local extinctions and economic impacts on seafood industries through declines in important fishery species and impacts on aquaculture. Extreme temperatures are increasingly seen as important influences on biological systems, yet a consistent definition of MHWs does not exist. A clear definition will facilitate retrospective comparisons between MHWs, enabling the synthesis and a mechanistic understanding of the role of MHWs in marine ecosystems. Building on research into atmospheric heatwaves, we propose both a general and specific definition for MHWs, based on a hierarchy of metrics that allow for different data sets to be used in identifying MHWs. We generally define a MHW as a prolonged discrete anomalously warm water event that can be described by its duration, intensity, rate of evolution, and spatial extent. Specifically, we consider an anomalously warm event to be a MHW if it lasts for five or more days, with temperatures warmer than the 90th percentile based on a 30-year historical baseline period. This structure provides flexibility with regard to the description of MHWs and transparency in communicating MHWs to a general audience. The use of these metrics is illustrated for three 21st century MHWs; the northern Mediterranean event in 2003, the Western Australia ‘Ningaloo Niño’ in 2011, and the northwest Atlantic event in 2012. We recommend a specific quantitative definition for MHWs to facilitate global comparisons and to advance our understanding of these phenomena