Trawling Effort Research Articles

Spatio-temporal variability among loggerhead turtle, Caretta caretta, strandings off southern Brazil

Abstract Since 2015, Brazilian legislation governing resource extraction in the Santos Basin has required daily monitoring of beaches (∼1490 km) in Rio de Janeiro (RJ), São Paulo (SP), Paraná (PR), and Santa Catarina (SC) for fauna strandings. All stranded specimens are necropsied or rehabilitated. Here, we investigate spatio-temporal variability among 5169 loggerhead turtles, Caretta caretta, stranded between 2015 and 2022, and discuss regional management implications. Weekly stranding rates among states ranged between 0.03 (RJ) and 0.54 (PR) C. caretta 100 km–1 and peaked during winter and spring—coinciding with concentrated regional penaeid-trawl effort. Almost all (99%) stranded C. caretta were dead and had advanced decomposition. Overall, there were biases towards female C. caretta (2:1), that increased during summer, and juveniles (2.2:1) across all states, especially in Paraná—encompassing an ecologically important and World Heritage-listed estuarine complex. Identified anthropogenic impacts among stranded C. caretta were low overall (14%) but biased towards fishing (8%) and greatest during winter and spring. Few (∼4%) C. caretta had ingested plastic or were entangled in marine debris. The data support prioritising the jurisdictional management of impacts across SP, PR, and SC during winter and spring, and in the presence of intensified regional trawling effort.

Quantification and mitigation of bottom-trawling impacts on sedimentary organic carbon stocks in the North Sea

Abstract. The depletion of sedimentary organic carbon stocks by the use of bottom-contacting fishing gear and the potential climate impacts resulting from remineralization of the organic carbon to CO2 have recently been heavily debated. An issue that has remained unaddressed thus far regards the fate of organic carbon resuspended into the water column following disturbance by fishing gear. To resolve this, a 3D-coupled numerical ocean sediment macrobenthos model is used in this study to quantify the impacts of bottom trawling on organic carbon and macrobenthos stocks in North Sea sediments. Using available information on vessel activity, gear components, and sediment type, we generate daily time series of trawling impacts and simulate 6 years of trawling activity in the model, as well as four management scenarios in which trawling effort is redistributed from areas inside to areas outside of trawling closure zones. North Sea sediments contained 552.2±192.4 kt less organic carbon and 13.6±2.6 % less macrobenthos biomass in the trawled simulations than in the untrawled simulations by the end of each year. The organic carbon loss is equivalent to aqueous emissions of 2.0±0.7 Mt CO2 each year, roughly half of which is likely to accumulate in the atmosphere on multi-decadal timescales. The impacts were elevated in years with higher levels of trawling pressure and vice versa. Results showed high spatial variability, with a high loss of organic carbon due to trawling in some areas, while organic carbon content increased in nearby untrawled areas following transport and redeposition. The area most strongly impacted was the heavily trawled and carbon-rich Skagerrak. Simulated trawling closures in planned offshore wind farms (OWFs) and outside of core fishing grounds (CFGs) had negligible effects on net sedimentary organic carbon, while closures in marine protected areas (MPAs) had a moderately positive impact. The largest positive impact arose for trawling closures in carbon protection zones (CPZs), which were defined as areas where organic carbon is both plentiful and labile and thereby most vulnerable to disturbance. In that scenario, the net impacts of trawling on organic carbon and macrobenthos biomass were reduced by 29 % and 54 %, respectively. These results demonstrate that carbon protection and habitat protection can be combined without requiring a reduction in net fishing effort.

Environmental variables and bottom trawling effort affect the complexity and distribution of soft-bottom octocorals and burrowing megafauna communities in the Gulf of Cádiz

Bottom trawling significantly impacts benthic communities, reducing habitat complexity and biodiversity. The distribution and abundance of key species in the northeastern Gulf of Cádiz, Spanish waters of Atlantic Ocean, such as soft-bottom octocorals and burrowing megafauna, were examined using video observations and Spatial Distribution Models developed with Random Forest. The study was conducted in the Site of Community Importance “Volcanes de fango del golfo de Cádiz" focusing on depths between 300 and 950 metres depth. The effects of environmental variables and bottom trawling on octocoral distribution and abundance were assessed, and management strategies for habitat protection were proposed. Bottom trawling was found to decrease habitat suitability for large octocoral species while the abundance of Norway lobster was positively correlated with certain values of bottom trawling effort. The study suggests that bottom trawling causes significant reduction in octocoral distributions, substrate homogenization, and habitat differentiation. A 200 km2 area is recommended for a specific bottom trawling regulation to protect soft-bottom octocorals and support the recovery of commercial burrowing megafauna.

Effect of environmental and anthropogenic factors on the distribution and co-occurrence of cold-water corals

Cold-water corals (CWCs) are bioengineering species that can increase habitat heterogeneity and improve the deep sea’s biological diversity and ecosystem functioning. Knowledge of their distribution provides a critical baseline for assessing the effect of natural and anthropogenic impacts on these important deep-sea habitats. The aims of this study are: i) provide new data on the spatial distribution of six CWCs species in the Strait of Sicily, ii) describe the principal environmental and anthropogenic variables that play a role in shaping their distribution, iii) identify hotspots in which individuals belonging to the various species co-occur. Presence-only data of six CWCs species, ten environmental variables (depth, slope, rugosity, aspect, flowdir, temperature, salinity, north bottom current, east bottom current, chlorophyll-a), and one variable relating to bottom trawling effort (Automatic Information System – AIS) were used to predict the suitable habitats. We used Maximum Entropy modelling (MaxEnt) approach and used the AUC (area under the receiver operating characteristic curve) and TSS (true skill statistics) to evaluate the model performance. The results showed excellent AUC, TSS and AUC’s standard deviation mean values for all six species. The validation show high predictive performance. MaxEnt identified slope, depth, and rugosity as the most important predictors, showing the highest percentage contribution for all six species considered. Throughout the study area, highlyinterspecific persistent density hotspot of CWCs co-occurrence were discovered, with a total extension of 4.05 km2 where all species co-occur. Although studies on the effect of environmental and anthropogenic factors that impact the distribution of these species of conservation interest remain scarce, the results of this study offer useful guidance for decision-makers to develop necessary conservation measures.

Benthic microbial biogeographic trends in the North Sea are shaped by an interplay of environmental drivers and bottom trawling effort

Microbial composition and diversity in marine sediments are shaped by environmental, biological, and anthropogenic processes operating at different scales. However, our understanding of benthic microbial biogeography remains limited. Here, we used 16S rDNA amplicon sequencing to characterize benthic microbiota in the North Sea from the top centimeter of 339 sediment samples. We utilized spatially explicit statistical models, to disentangle the effects of the different predictors, including bottom trawling intensity, a prevalent industrial fishing practice which heavily impacts benthic ecosystems. Fitted models demonstrate how the geographic interplay of different environmental and anthropogenic drivers shapes the diversity, structure and potential metabolism of benthic microbial communities. Sediment properties were the primary determinants, with diversity increasing with sediment permeability but also with mud content, highlighting different underlying processes. Additionally, diversity and structure varied with total organic matter content, temperature, bottom shear stress and bottom trawling. Changes in diversity associated with bottom trawling intensity were accompanied by shifts in predicted energy metabolism. Specifically, with increasing trawling intensity, we observed a transition toward more aerobic heterotrophic and less denitrifying predicted metabolism. Our findings provide first insights into benthic microbial biogeographic patterns on a large spatial scale and illustrate how anthropogenic activity such as bottom trawling may influence the distribution and abundances of microbes and potential metabolism at macroecological scales.

To trawl or not to trawl: Questioning core assumptions of trawl placement choice in fisheries acoustics surveys

In acoustic-trawl surveys, acoustic echosign needs to be biologically characterized, and if done correctly, will lead to accurate biomass estimates, robust stock assessments, and ensuing healthy fish stocks. However, methods for validating the core assumption that trawl placement choice yields a representative sample of the associated echosign (given an ideal net) are rarely described. Therefore we detail several such methods, using Pacific hake as a case study, exploiting both historic survey data as well as additional field experimental data. Specific methods focused on validation of (1) trawl effort spatially matching backscatter distributions, (2) trawled-location backscatter amounts matching all-location backscatter amounts, (3) trawled depth matching backscatter depth, and (4) spatial homogeneity of fish length within an aggregation. Application of the methods to the adult Pacific hake survey generally validated the assumption that trawl placement choice yielded a representative sample of the associated echosign, except for two instances. The backscatter from fished aggregations was greater than that from general aggregations in one of the two survey years analyzed. In addition, experimental field data detected a slight but significant trend of longer fish in the offshore portion of an aggregation. Neither of these occurrences are expected to yield a bias in the biomass estimate of Pacific hake.

Mapping fine-scale demersal trawl effort for application in ecosystem assessment and spatial planning

Fine-scale maps of fishing activity are valuable information layers for fisheries management, assessments of biodiversity impacts and marine spatial planning. Our aim was to develop an accurate map of demersal trawling intensity in South Africa and to demonstrate its utility at a national scale. We calculated a swept area ratio, representing demersal trawling effort for the entire study period (2005‒2018) and annually. We then plotted spatial and temporal patterns of trawling activity, identified core fishing areas, and examined spatial overlap between trawling, South Africa’s marine ecosystem types and the national network of marine protected areas. A high proportion of trawling effort (90%) was concentrated in 43% of the area exposed to trawling, with the remaining 10% spread across 57% of the fished areas. The fishery overlaps with 33 of 150 benthic and bentho-pelagic marine ecosystem types. Of those, 11 have more than 50% of their extent, and five have more than 80%, within the trawl ring-fence. Our analyses support a systematic prioritisation of ecosystem types for further management and protection. The new South African trawling-intensity map contributes an improved pressure layer for ecosystem assessments, can help identify priority fishing areas and has application in conservation, marine spatial planning and fisheries management.

ANALISIS USAHA PUKAT CINCIN (PURSE SEINE) PADA KM. DOA RESTU-01 DI PERAIRAN GORONTALO UTARA, GORONTALO

This research took place from July 2019 to June 2020 at the Gentuma Fish Landing Port, North Gorontalo and MV. Doa Restu-01. The study of financial analysis of new boats within one year provides information to the government and the community as an effort to increase fishermen's income. This study aims to determine the feasibility analysis of purse seine vessels in the waters of North Gorontalo. The data taken in the form of primary and secondary data. The data in the analysis uses descriptive analysis and quantitative analysis as well as financial analysis in the form of Profit-Loss (Income Statement), Benefit Cost Ratio (BCR), Break Even Point (BEP), Payback Period (PP) and Return Of Investment (ROI). The results show that the ring trawling effort at Gentuma meets the requirements and deserves to be continued. The results of the calculation of business feasibility in the purse seine fishing business of MV. Doa Restu-01 based on the projected profit and loss (R/L) the profit earned for 1 year is Rp. 113.856.050,-, the cost benefit ratio (B/C ratio) 1.10, Payback Period (PP) 9.61 years, income on investment (ROI) 10.40%, Break Even Point (BEP) unit 68,385 kg and Break Even Point (BEP) price Rp.965,499,137,-

Mapping habitat loss in the deep-sea using current and past presences of Isidella elongata (Cnidaria: Alcyonacea)

Abstract The bamboo coral Isidella elongata is an engineering species that forms a characteristic biogenic habitat in the bathyal mud of the Mediterranean Sea. This habitat has been severely reduced in recent decades due to trawling impacts, and there is a growing concern about its conservation status. In this work, the habitat loss of I. elongata was computed using a novel approach that combines the realized niche of the species with the estimation of its past distribution (before trawling) to delineate potential areas of habitat loss with different levels of uncertainty. The realized niche of the species was modelled using only live colonies and including trawling effort as explanatory variable whereas the past distribution was estimated also using the leftovers of dead colonies as presences. Trawling effort had a statistically significant negative effect on the extent of the realized niche of I. elongata, confirming previous results on the impact of this pressure on its distribution. The novel approach used in this work has allowed us to map for the first time several areas of potential habitat loss for I. elongata in the studied area, opening new opportunities to provide this essential information for future management and restoration actions of vulnerable marine ecosystems worldwide.

Assessing discards in an illegal small-scale fishery using fisher-led reporting

About a third of all marine fish in the world are caught in Small-Scale Fisheries (SSF). SSF are increasingly recognised as essential for food security and livelihoods for vulnerable and economically fragile communities globally. Although individual SSF vessels are usually perceived as having little impact on the ecosystem, the cumulative impact of gear type and number of vessels may be substantial. Bottom trawling is a common fishing method that can greatly influence the marine ecosystem by damaging the seafloor and generating high levels of discards. However, appropriate sampling coverage using on-board observer programmes to collect these data from SSF are rare, as they are expensive and pose logistical constraints. A mobile App was used to assess whether self-reporting by fishers could provide reliable fine-scale information on fishing effort and discards over time in an illegal shrimp trawling fishery in northern Peru. Maps depicting the spatial distribution of trawling effort and the proportion of discards from observers and fishers were compared using the Similarity in Means (SIM) Index, which ranges from 0 when spatial patterns differ completely to 1 when spatial patterns are very similar. High levels of agreement between spatio-temporal patterns of effort (SIM Index = 0.81) and discards (0.96) were found between fisher and observer maps. Moreover, far greater spatial coverage was accomplished by fishers, suggesting that self-reporting via an App represents a useful approach to collect reliable fisheries data as an initial step for effective monitoring and management of these fisheries.

Bottom trawling in sponge grounds of the Barents Sea (Arctic Ocean): A functional diversity approach

In the Barents Sea, extensive aggregations of sponges are known to occur, especially in the southwestern portion dominated by large species of Geodia spp. The distribution of deep-sea sponge grounds, considered vulnerable marine ecosystems, often coincides with high fishing efforts targeting demersal fish species and benthic invertebrates using bottom trawls. The aim of this study was to investigate the effects of bottom trawling on the abundance of habitat forming Geodia spp., and on the size composition of Geodia barretti together with functional and species diversity of associated fauna. Using images collected by a Remotely Operated Vehicle, we compared two locations with contrasting levels of trawling effort. We found significantly smaller Geodia barretti in the intensely trawled area as well as differences in species and functional diversity between the two sites. This study provided clear evidence that bottom trawling significantly alter sponge associated communities, significantly reducing the abundance and size of geodiid sponges, and creating a shift in functional diversity. The effects of bottom trawling on Geodia barretti and Geodia spp. grounds are noticeable and results should be used in conservation and management of these diverse sponge grounds.

Defend as You Can, React Quickly: The Effects of the COVID-19 Shock on a Large Fishery of the Mediterranean Sea

This paper presents an analysis of the effect of SARS-CoV-2 coronavirus pandemic and related restrictive measures on the activity of the Italian fleet of trawlers, which represents one of the most important fisheries in the Mediterranean Sea. We integrated multiple sources of information including: (1) Fleet activity data from Vessel Monitoring System, the most important satellite-based tracking device; (2) vessel-specific landing data disaggregated by species; (3) market and economic drivers affecting the effort variation during the lockdown and in the related fishing strategies; (4) monthly landings of demersal species in the main Italian harbors. These data sources are combined to: (1) Assess the absolute and relative changes of trawling effort in the geographical sub-areas surrounding the Italian coasts; (2) integrate and compare these changes with the market and economic drivers in order to explain the observed changes in fishing effort and strategy; (3) analyze the changes of the fishing effort on the Landing-per-unit-effort (LPUE) in order to further understand the strategy adopted by fishers during this crisis and to infer the potential consequence for the different stocks. The results provide an overview of the effects of the “COVID-19 shock,” in terms of fishing activity and socio-economic drivers, demonstrating that the consequences of the pandemic have been very varied. Although the COVID-19 shock has caused a marked overall reduction in activity in the first semester of 2020, in some cases the strategies adopted by fishermen and the commercial network linked to their activity have significantly reduced the impact of the emergency and taken back catch and effort to levels similar to those of previous years. These results could provide insights for management measures based on temporal stops of fishing activities. In particular, if no limits to the fishing effort after the restart of fishing activities are adopted, the benefits of fishing pressure reduction on fishery resources could be nullified. On the other hands, when fishing activities restart, and in the absence of catch control, effort tends to increase on coastal bottoms characterized by greater abundance of resources and longer effective fishing time.

Commercial fishery bycatch risk for large juvenile and adult smalltooth sawfish (Pristis pectinata) in Florida waters

Abstract Incidental catch of marine species can create ecological and economic issues, particularly for endangered species. The smalltooth sawfish (Pristis pectinata) is endemic to the Atlantic Ocean and listed as Endangered in the US Endangered Species Act. One of its major threats is bycatch mortality in commercial fisheries. Despite the protection afforded by the US Endangered Species Act, smalltooth sawfish are still captured as bycatch in commercial fisheries. Acoustic and satellite tag data collected on 59 sawfish between 2011 and 2019 were analysed to assess commercial fishery bycatch risk for large juveniles and adults off Florida. This study focused on shrimp trawl, south‐east coastal gillnet, and shark bottom longline fisheries, as these were identified in the recovery plan as having the greatest potential threats to recovery. Bycatch risk associated with the shrimp trawl fishery was significantly higher than the other fisheries, indicating that this fishery currently poses the greatest threat to recovery. Bycatch risk was concentrated in all seasons in the Gulf of Mexico adjacent to the lower Florida Keys for the shrimp trawl fishery, off Cape Canaveral in the south‐east coastal gillnet fishery, and in the Atlantic Ocean adjacent to the Florida Keys in the shark bottom longline fishery. Tagging location and sex were predictors of bycatch risk. Individuals tagged in Charlotte Harbor had the highest shrimp trawl bycatch risk. Females tagged in south Florida tended to reside in the deepest water, which is where shrimp trawl effort is highest. Therefore, females may be at more risk in these deeper waters. Results from this study indicate a year‐round closure of waters off south‐west Florida to the shrimp trawl fishery between Charlotte Harbor and the western Florida Keys would reduce sawfish bycatch, and thus mortality, which is in line with recovery plan goals.

Spatial assessment of benthic habitats vulnerability to bottom fishing in a Mediterranean seamount

Physical damage caused by the mechanical impact of bottom fishing gears on epibenthic community can reduce the biomass and coverage of habitat-forming species as well as the richness and diversity of the rest of the associated community. A practical development of a methodology for spatially assessing the potential degree of disturbance that benthic habitats suffered as a consequence of trawling and long-lining was carried out using a seamount located within a marine Natura 2000 site in the western Mediterranean as a case of study. By jointly assessing the extent of the impact and mapping the sensitivity of all the habitats to these fishing activities, vulnerability and disturbance per benthic habitat and pressure type was evaluated. Habitat sensitivity and fishing effort were combined using a disturbance matrix which categorize grid cells in 9 different levels of disturbance. Additionally, different thresholds of probability of presence of the different habitats obtained from distribution models were used to identify priority conservation and potential recovery. Around 50% of the area was disturbed by fishing and all habitats, both biogenic and non-biogenic, were subjected to fishing. Most of the trawling effort was carried out on soft bathyal substrates while the percentage of longlining effort carried out on hard bottoms was relatively higher than for trawling. Biogenic habitats showed significantly greater sensitivity to both trawling and longlining than non-biogenic habitats. Disturbed, priority conservation and potential recovery areas were identified and mapped in order to inform marine spatial planning.

Deep-sea benthic habitats and the impacts of trawling on them in the offshore Greenland halibut fishery, Davis Strait, west Greenland

Abstract The offshore Greenland halibut (Reinhardtius hippoglossoides) fishery, west Greenland, employs demersal trawl gear at depths of 800–1400 m. In contrast to many deep-sea fisheries, the target stock appears stable and the fishery is of significant economic importance. Recent Marine Stewardship Council certification of this fishery highlighted the paucity of knowledge of benthic habitats and trawling impacts, which this study aimed to address using a towed benthic video sled. The spatially discrete northern and southern areas of the fishery were found to be distinct in terms of the communities present, which non-metric multidimensional scaling suggests is primarily driven by temperature. Extensive physical evidence of trawling was observed. Trawling effort was significantly linked with community composition, with a negative association between trawling effort and abundance of some taxa, including some vulnerable marine ecosystem (VME) indicator species. Three potential VMEs are identified: (i) Flabellum alabastrum cup coral meadows; (ii) a Halipteris finmarchica sea pen field; and (iii) areas exhibiting mixed assemblages of VME indicators. Of immediate conservation concern is a H. finmarchica field, which seems to be at least regionally rare, is situated within the fringes of existing trawling effort and is currently afforded no protection by management measures.

Gathering local ecological knowledge to augment scientific and management understanding of a living coastal resource: The case of Oregon’s nearshore groundfish trawl fishery

Globally, coastal nearshore regions are an intersecting point for human and biological productivity, often serving as hotspots for subsistence, commercial, and recreational fishing activities. Despite this, many nearshore areas remain poorly understood, monitored or managed. This case study examined the nearshore sector of Oregon’s groundfish trawl fishery, which exists in shallow estuarine and continental shelf habitats common along the West Coast of North America; areas that are important for early life history stages of many commercial and recreational fisheries. The West Coast groundfish fishery includes over 90 different species, 40 of which occur within Oregon’s nearshore (here defined as the portion of the shelf extending seaward to a water depth of 200 m). The very shallow portions of the Oregon Coast (the area of the shelf inshore of 55 m) have been subject to limited scientific survey monitoring, and much of the details of the ecology, health, and processes in these habitats remain poorly understood. The utilization of the nearshore region by the commercial groundfish trawl fleet is also minimally documented despite the fact that experiential knowledge (local ecological knowledge [LEK]; trawl logbooks, fish tickets, interviews) exists. This research explored the capacity of capturing LEK sources to inform and enhance understanding of the drivers of effort and the vitality of nearshore fishery resources. Our approach used statistical analysis and mapping of nearshore trawl effort from 1981 to 2017 and gathered semi-structured interviews of intergenerational fishermen to bolster data-poor areas. Insights provided by sampling strategies and historical to current knowledge of access to groundfish assemblages provide informed baselines for future management. Spatial mapping results revealed a decline in trawl effort on the Oregon continental shelf thought time. Logbook and interview data assessment illuminated market and ecological drivers of fishing behavior as well as a unique sector of the groundfish fleet in Oregon: the beach fleet, with unique market and socio-economic challenges. Findings indicate a mixed-methods approach can provide a more thorough assessment of long-term interest in Oregon’s nearshore groundfish fishery. Ensuring better understanding of coastal interfacing regions such as Oregon’s nearshore insights potential for better conservation and utilization of marine resources and improved monitoring in resource limited management contexts.

Biomass of slow life history species increases as local bottom trawl effort decreases in the Celtic sea

Due to its selective removal, fishing pressure has long influenced the dynamics of species based on their life history traits. Sensitivity to fishing increases along a “fast-to-slow” gradient of life history strategies, and the “slow” species (large, long-lived, late-maturing, giving birth to few large offspring) require the most time to recover from fishing. In the North East Atlantic, after having reached extreme levels, fishing pressure has decreased since the 1980's due to management measures such as total allowable catch (TAC) or area closure. An effect on the distribution of species as well as a potential recovery could be expected. However, temporal patterns of life history strategies are rarely linked to management measures. In addition, a larger emphasis is often put on exploited or emblematic sensitive species but rarely on assembly processes at the ecosystem scale (both commercial and non-commercial species). Based on a 17-year time series of 101 taxa (fishes, elasmobranchs, bivalves, cephalopods and crustaceans), we observed a negative relationship between the biomass of taxa sensitive to fishing and bottom trawling pressure, as well as an increase in their total biomass in the Celtic Sea. Over the whole area, stochasticity appeared as the dominant assembly process. Deterministic assembly processes were at play in the centre of the area where significant overdispersion (caused by the presence of both slow and fast taxa) were observed. The absence of sensitive taxa from the rest of the Celtic Sea appeared to be caused mainly by a historical effect of environmental filtering when fishing was high. At the local scale, we related the decrease in fishing pressure to the increase in biomass of five of the most sensitive taxa. This local decrease in fishing pressure, resulting from the implementation of an area closure, highlights the positive effect of such management measures in less than two decades.

A Win-Win for Deep-Sea Corals and Fishing: Increasing Seafloor Protections While Restoring Fishing Opportunities Off the United States West Coast

On January 1, 2020, the United States (U.S.) government implemented new regulations increasing total closed areas to bottom trawl fishing by 363,513 km2, including a net increase of 44,498 km2 in essential fish habitat conservation areas at fishable depths (<1,280 m) along the West Coast continental shelf and upper slope. At the same time, the government reopened certain bottom trawl fishing grounds originally established to rebuild overfished groundfish. In combination with previously existing conservation areas, the result of these regulations is that bottom trawl fishing is now prohibited in 90% (739,491 km2) of ocean waters in the United States West Coast Exclusive Economic Zone, including 32.6% of shelf (<200 m) depth zones and 56.0% of upper slope depth zones (200-1,280 m), with a disproportionate focus on priority habitat features that are proxies for fish habitat, sensitivity to bottom trawling, and biodiversity. The final spatial management measures include 53 new or modified habitat conservation areas closed to bottom trawling in fishable depths (<1,280 m) and a precautionary prohibition on all bottom contact fishing gears at depths greater than 3,500 m. Together the final set of habitat conservation area closures and openings result in an overall increase in coastwide protections for hard, mixed, and soft substrates; seamounts; submarine canyons; and known and predicted coral, sponge, and pennatulid locations. Finer scale analyses indicate net increases or no change in coral and sponge observations inside protected areas across all regions and depth zones, despite some reductions in total area and hard substrate protected in certain regions. Based on historic bottom trawl effort data, we estimate that the opening of previously closed areas restores 24.6% of fishing effort that was displaced by bottom trawl closures implemented prior to 2020. Here we describe the involvement and approach of the conservation organization, Oceana, to protect seafloor habitats off the United States West Coast, which included a coastwide proposal to modify conservation areas, geospatial analyses, grassroots organizing, media stories, and scientific expeditions using remotely operated vehicles. Our comparison of the new versus previous assemblage of habitat conservation areas demonstrates increased overall habitat protection and fishing opportunities throughout depths and bioregions off the United States West Coast.

Incidental capture of seabirds in Argentinean side-haul trawlers

SummaryBetween April 2008 and July 2015, we conducted a total of 18 trips on five different side-haul trawlers fishing within the Argentine Exclusive Economic Zone, monitoring 486 hauls. We observed 100% of the hauls and monitored trawl cables for 136.7 hours, about 5% of the trawl effort, to identify the levels of seabird bycatch from net entanglements and collisions with trawl cables. A total of 35 net entanglements of White-chinned Petrels Procellaria aequinoctialis, Great Shearwaters Ardenna gravis, Black-browed Albatrosses Thalassarche melanophris and Southern Royal Albatross Diomedea epomophora were recorded, all of which occurred during the autumn and winter. Additionally, 656 seabird collisions against trawl cables were recorded including 39 heavy, 96 medium and 521 light. Further, we recorded nine Black-browed Albatrosses and two Great Shearwaters potentially dead. Although in the study fishery the number of deaths in the trawl cables could surpass the number of birds incidentally killed in nets, the mortality rate caused by the latter type of interaction far exceeds those observed in nets from other trawl fisheries operating in the Patagonian Shelf. Fortunately, 26% of the seabirds entangled in the net were recovered and released alive, which indicates that awareness and training in safe bird handling and release may improve captured seabird survival rates. The main objectives of this work is to highlight a little-studied source of seabird mortality by entanglement, to generate discussion on potential technical mitigation measures for side-haul trawl fisheries, and to propose crew training in safe handling and release of seabirds as an immediate mitigation measure.

Recent fishing footprint of the high-seas bottom trawl fisheries on the Northwestern Hawaiian Ridge and Emperor Seamount Chain: A finer-scale approach to a large-scale issue

A standing data gap for management of high-seas seamounts of the Northwestern Hawaiian Ridge and Emperor Seamounts (ES-NHR) by the North Pacific Fisheries Commission is the footprint of fisheries activities on these seamounts. Using satellite AIS data and the algorithms of the publicly available Global Fishing Watch database, a spatial map of trawling in a 0.01-degree latitude by 0.01-degree longitude square grid was created to review the data available to map this footprint. From 2012 to 2018 much of the trawling effort for all countries focused on Koko, Yuryaku, Kammu, and Colahan Seamounts at depths between 400 m (summits) and the depth limit currently set by the North Pacific Fisheries Commission of 1500 m. Additional seamounts with fishing activity included Annei (North Koko), Kinmei, Jingu, and Suiko. The remaining ES-NHR seamount locations show no trawling in those years. Bottom contact fishing was predominately carried out by ships with flag states of Japan and Korea. To date there appears to be compliance with the recent small-scale closures on C–H seamount and Koko.An additional source of data comes from scientific Autonomous Underwater Vehicle (AUV) surveys in 2014 and 2015 from three of these seamounts, in which scars from bottom contact gear are readily visible. These cover a smaller spatial area and depth range than the satellite data, but indicate the full footprint is not encompassed by the satellite data, suggesting either the fishing footprint is not fully captured by the AIS approach or that the footprint has shifted through time. AUV surveys also provide data on areas where abundant megafauna occur, which can provide candidate starting points for VME management efforts and further closures, similar to ones already in effect in the ES-NHR. The combination of satellite and AUV data provide a finer-scale fisheries footprint for this region that can aid in management of these sites.