First record of the deep-sea caridean shrimp <i>Notostomus auriculatus</i> Barnard, 1950 (Crustacea: Decapoda: Acanthephyridae) in the southwestern Atlantic Ocean

Given the array of concerns about bottom trawling – and the many attempts to provide reassurance about its sustainability – it is surprising and worrying how little we know about the effects of these fisheries on ocean spaces and species. Our study uncovers critical gaps in our understanding of the global impact of bottom trawling on marine ecosystems, highlighting the challenges these knowledge deficiencies pose for effective environmental, social, and economic management. Our extensive literature survey reveals significant skews in global understanding of the ecological impacts of bottom trawling, in four respects. First, just 164 of the 4000 bottom trawling related papers and reports we screened focused on the gears’ ecological impacts (~4%). Second, relevant assessments have been biased toward the global north (90% of studies), especially the North Atlantic Ocean (48%) and the Mediterranean (21%), despite the majority of BT pressure occurring in the global south. Third, most papers focused on impacts to marine organisms (85%) rather than habitats (30%), with some overlap. Fourth, invertebrates (particularly epifauna) received more attention than vertebrates (56 and 38%, respectively), whereas studies of habitats were more evenly distributed across biogenic and non-biogenic substrates. In all primary research that we surveyed, under one-third of the studies explored impacts of bottom trawling on fish. However, our deep dive into FAO reports (n=2852 studies reviewed and 200 retained), complemented by primary literature (n=36 papers) for data-deficient regions, has so far documented at least 3053 fish species caught by bottom trawlers in national waters (four times previous estimates), spanning 1050 genera, 313 families, 72 orders, and 5 classes. The real number will be greater, as studies predominantly documented medium to large-bodied species (mean max length = 68 ± 3 cm), some studies mentioned unrecorded species, and key bottom trawling regions were underrepresented in FAO reports. About one-tenth of species caught by bottom trawls are assessed as threatened on the IUCN Red List, and 51% as Least Concern. However, 38% were Data Deficient or had not yet been assessed. Our research underscores the pressing need to address the limitations and imbalances in our understanding of the ecological impacts of bottom trawls. These biases and gaps in our understanding means we are allowing bottom trawling without adequate information on the challenges it is posing – placing the burden of proof on ocean ecosystems and ocean dependent people. We advocate for a more representative – and thus holistic – analysis of bottom trawling that encompasses a wider range of regions and taxa. Full understanding is vital to determining the role of bottom trawling in a sustainable ocean future. After all, we cannot manage what we do not know.

Spatio-temporal trends of the bottom trawling activity in a mud volcano field of the north-eastern Gulf of Cádiz (south-western Iberian Peninsula)

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

The structure of estuarine fish assemblages at temperate latitudes in Patos Lagoon (32º05'S, 52º04'W), Rio Grande do Sul, Brazil and York River (37º17'N, 76º33'W), Virginia, USA was compared using mid and late 1970's data from bottom trawl collection to investigate whether geographically isolated fish assemblages have similar ecological structure given similar latitudinal positions on the warmtemperate southwestern and northwestern Atlantic regions, respectively. Since estuarine species often exhibit an ontogenetic shift in habitat requirements or preferences we examined Capture per Unity of Effort by size class (CPUE-SC) and split species into "size ecological taxa" (SET) for analysis. The use of CPUE-SC also allowed the abundance of a SET to be computed by summing the mean CPUE of each size class within that SET and use this information to follows SET's temporal and or spatial abundance. A total of 65 and 63 species was collected during a year of bottom trawling in the Patos Lagoon and York River estuaries, respectively. In both localities the strongest modal size class was < 80 mm TL, and several abundant species were smaller than 100 mm TL. The size between 80 and 100 TL effectively separated several species into discrete SET's in both systems. Those SET's could have different ecological preferences, temporal and spatial distributions and so identified as different "ecological taxa". In warm months, when predation by large fish is most likely, the abundance of fish between 80 and 100 mm TL in "bottom trawl" demersal fish assemblages was low in both systems. Only the sea catfishes, in Patos Lagoon, protected by strong dorsal and pectoral spines, and the Hogchoker, in the York River, protected by burrowing in the bottom substrate, peak in abundance at this size class. The seasonal pattern of estuarine use was similar between localities and did not differ from other warm-temperate estuarine fish assemblages.

The aim of this work is to explore the maternal genetic diversity of hunter-gatherers of the southern Tierra del Fuego, specifically the north coast of Beagle Channel, the Península Mitre, and Isla de los Estados through ancient mitochondrial DNA analysis. The hypervariable regions 1 and 2 of the mitochondrial genome of five individuals from the north coast of Beagle Channel, six individuals from Península Mitre, and one individual from Isla de los Estados were analyzed. Through diversity statistics, Analysis of Molecular Variance (AMOVA), and Median Joining networks analyses, maternal relationships in the region were evaluated and phylogenetic similarities between ancient and contemporary populations of Tierra del Fuego were determined. The mitochondrial DNA lineages from the ancient individuals analyzed reveals the presence of subclades C1b and D1g. Pattern of decreasing genetic diversity toward the South is observed. The AMOVAs performed found no statistically significant differences between individuals of the north coast of Beagle Channel and Península Mitre-Isla de los Estados, and modern Yámana populations. Median joining network of haplotypes of clades C1 and D1g, show the same results. Ethnohistoric and ethnographic records of Península Mitre show that this region was occupied during the 19th century by Haush or Manekenk populations, although their biological, cultural, and subsistence characterization is unclear. We explore their maternal lineages and encounter low levels of genetic diversity and the absence of population differentiation with modern Yámana groups. We suggest that Península Mitre-Isla de los Estado was part of the same hunting and gathering populations as those of the Beagle Channel.

Fisheries interactions with non-target marine vertebrates are a worldwide problem. The impact of coastal bottom trawl fisheries on marine mammals has never been evaluated before in the Rio de la Plata Estuary and the adjacent Atlantic Ocean. Our aim was estimating the bycatch per unit effort (BcPUE) and incidental mortality rates of marine mammals caused by the industrial coastal bottom trawl fisheries fleet. We evaluated the mortality of three species ( i.e ., franciscana dolphin Pontoporia blainvillei , South American sea lion Otaria flavescens , and the South American fur seal Arctocephalus australis ); these species are facing conservation problems either at the regional or local scale. We conducted an onboard data collection program of marine mammals' bycatch involving crew members of 10 vessels (30%) of the Uruguayan coastal bottom trawl fleet between January 2009 and April 2012. A total of 102 marine mammal individuals were bycaught during 490 fishing trips involving 2,398 fishing days. Mortalities estimated for franciscana dolphin were the highest among the species affected, with values adding up to ~100 individuals for year (with scenarios of population decline in the area), followed by South American sea lion with ~77 individuals by year (0.8% of local population) and the South American fur seal with an annual mortality estimate of ~25 individuals (~0.02% of local population). BcPUE showed significant temporal variation, with franciscana dolphin BcPUE varying seasonally and those of otariids according to their breeding season. Our estimates of marine mammal bycatch by bottom trawl fisheries should constitute an important input for the sustainable management of fisheries and the conservation of marine biodiversity in the southwestern Atlantic Ocean.

The distribution patterns of fish early life stages are critical to recruitment success and closely related to major oceanographic circulation patterns. We explored the spatiotemporal distribution of early life stages of Fuegian sprat Sprattus fuegensis, a key trophic species in the Southwestern Atlantic Ocean (SWAO), in a complex oceanographic setting. Samples were collected during austral spring, summer, and autumn, from 2014 to 2017, across areas with distinct biophysical properties between Tierra del Fuego (TDF) and the marine protected area ‘Namuncurá’ at Burdwood Bank (BB) (ca. 54°S). Results revealed significant seasonal fluctuations in abundance, distribution, and ontogenetic composition across habitats. High egg and early larval abundances at Isla de los Estados (IE) suggest it is an additional spawning ground to those previously identified at TDF and BB. However, only the latter appear to be suitable nursery areas. Particle-tracking simulations based on egg abundance and spawning dates were conducted for the first time using results from a high-resolution hydrodynamic model. Particle transport provides evidence of connectivity between IE and neighbouring areas—enhanced when horizontal diffusivity is incorporated into the model—but not between TDF and BB. Simulated distributions closely resembled empirical patterns from this and other studies, allowing the integration of empirical and modelled data to schematize the species’ dispersal pathways in the study area. These results offer new insights into distribution and connectivity patterns among spawning grounds and highlight the potential use of hydrodynamic models for future assessments of Fuegian sprat and other planktonic species’ dispersal and recruitment in the SWAO.

Spatial and temporal variation of microplastic in mussels from intertidal and subtidal banks in the Southwestern Atlantic Ocean.

What a drag: Quantifying the global impact of chronic bottom trawling on continental shelf sediment

Visual surveys can reveal rather different 'pictures' of fish densities: Comparison of trawl and video camera surveys in the Rockall Bank, NE Atlantic Ocean

External damages are indicators of the overall quality of fish and fish welfare. Haddock is an important commercial species widespread in the North Atlantic, but few studies related to quality have been carried out on this species. We studied the levels of external damages on haddock captured with a demersal trawl in the Northeast Atlantic. Further, we investigated to what extent the compulsory sorting grid and diamond mesh codend gear configuration employed in this trawl fishery is responsible for the external damages observed during the capture process. We evaluated external damages on 563 haddock captured over 22 hauls. In general, the results showed that catching haddock without any gear inflicted damages using demersal trawls is challenging. However, the results also showed that the severity of most damages is low and the probability to catch haddock with no external damage can be significantly increased removing the grid and changing codend design.

The present report is the northernmost capture of the piscicolid leech Stibarobdella moorei in the western South Atlantic Ocean. This is also the first time S. moorei is found associated to a batoid fish in the Brazilian coast, the eyespot skate Atlantoraja cyclophora. Stibarobdella moorei was found fixed in the dorsal side of a male eyespot skate, caught by bottom trawl around of the São Paulo coast, southeastern Brazil. A brief description of the morphology of the parasite and a discussion on the taxonomic status of the S. moorei are presented.

Late-Holocene and Little Ice Age palaeoenvironmental change inferred from pollen analysis, Isla de los Estados, Argentina

This cruise was a part of the “Verbundprojekt BIOACID” (Biological Impacts of Ocean ACIDification) Phase II (consortium 4 of 5), funded by the German Ministry for Education and Research (BMBF). It was also connected to the Norwegian-German collaborative project Tibia (“Trophic interactions in the Barents Sea - steps towards an Integrated Ecosystem Assessment (TIBIA)”, see www.caff.is/marine/marine-expert-networks/benthos) between AWI and the IMR in Tromso. The main objectives of this cruise were to elucidate whether climate change (mainly ocean acidification and warming, OAW) affects interacting species differently due to divergent physiological optima and ranges, expressed in thermal tolerance windows and associated performance capacities and phenologies of specific life stages. To determine the degree of the ongoing ‘Atlantification’ of the waters around (Western) Svalbard, we took sediment samples to analyse the benthic epi- and meiofauna. Further, we intended to obtain specimens of both Polar cod (B. saida) and Atlantic cod (G. morhua) in the Atlantic and polar waters around Svalbard, which were used in experiments on board and back at the Alfred Wegener Institute. We left port in Tromso in the morning of September 11th, heading North towards Svalbard. In the morning of September 13th, we reached the first scientific station in Hornsund, where a CTD was deployed. Following this, we ran several juvenile fish trawls with fish lift at different depths from surface waters to close to the bottom, specifically aiming for flocks of juvenile fish under the surface, at the thermocline and above ground (water layers of interest derived from CTD and EK60 profiles). In Hornsund, bottom waters were around 0°C cold and contained polar cod (Boreogadus saida). After fishing, we deployed several box grabs for sampling the first 30cm of sediment. This daily sampling protocol was repeated at all other stations unless stated otherwise. After a day of cruising, we reached North East Svalbard and sampled two stations at the center and opening of Rijpfjorden on September 15th and 16th, the protocol here was substantiated by several bottom trawls that yielded surprisingly little material. Afterwards, we moved into Hinlopen Strait, sampling waters of Atlantic and Barents Sea origin in a northwest-southeast transect during September 17th and 18th. The following day found us back in biologically diverse Atlantic waters at the Northwestern tip of Svalbard around Moffen Island, yielding schools of larval/juvenile herring, capelin, redfish and polar cod (and a few 0-class Antlantic cod) in the surface waters as well as a bottom trawl of mostly adult Atlantic cod (Gadus morhua) and several haddock (Melanogrammus aeglefinus). On our way to the AWI Hausgarten, we stopped over on the Yermak plateau on September 20th, where we found similar diversity as the day before. On September 21st, we sampled AWI Hausgarten with CTD, box grabs and several shallow juvenile fish trawls under deteriorating weather conditions. We therefore had to abandon our sampling schedule and the following days found us moving back and forth between shelter in Kongsfjord, Forlandsundet and Krossfjorden and the open water towards the Hausgarten, trying to complete the transect Kongsfjord-Hausgarten. This transect showed a succession of juvenile/larval fish species dominated by redfish (Sebastes sp.) in the open ocean towards Polar cod (B. saida) close to the shore (further abundant species included herring and capelin). Sampling in Forlandsundet revealed a rich and diverse ecosystem with polychaetes, annelids, holothurians, echinoderms and crustaceans (mainly Hyas araneus), again dominated by Atlantic cod (G. morhua). The last stations of the cruise were carried out in Billefjord on September 27th and 28th, here, the very cold bottom waters (-1,7°C) were populated by Polar cod as the only fish species plus several spider crabs (H. araneus). On September 29th, we handed over RV Heincke in Longyearbyen to the chief scientist of HE 451.2, Dr. Katrin Latarius. Thus ended a successful cruise, in which we were able to carry out about 90% of the planned station work, took a great amount of sediment and biological samples and brought around 150 juvenile Polar cod and about 60 juvenile Atlantic cod back to the home institute in Bremerhaven alive.

Specimens and eggs masses of the gastropod Trochita pileus were collected during a research cruise by bottom trawling at depths between 82 m and 120 m. Adult T. pileus were found attached to such hard substrata as the shells of scallops and oysters. The egg mass of T. pileus is composed of 7–8 transparent, triangular-shaped egg capsules fixed to the substratum with stalks. Four egg masses collected from brooding females, with a total number of 241 embryos, were examined. Trochita pileus is a protandrous hermaphrodite, and histological studies of the male, transitional, and female gonads were performed. The testicular portion of the gonad in both male and transitional individuals and the ovary of the female were studied by histological techniques. Spermatogenesis was observed for males and transitional individuals.