Discards from a deep-sea shrimp fishery in Angolan waters (SW Africa)

A programme of observers on board Spanish shrimp trawlers in Angola was initiated by IEO in 2018 in order to improve the scientific information required by Sustainable Management of External Fishing Fleets (SMEFF Regulation of the EU). In this context, discard studies are considered very relevant, both for assessment purposes and for obtaining information on adverse ecological impacts in marine ecosystems. Most fishing hauls performed during the observed period November 2018 to December 2019 were carried out at depths between 384 and 649 m, with classic bottom otter trawl targeting the striped red shrimp Aristeus varidens. Discards accounted for 60% of the total catch during the analysed period. The estimated global discard rate for 2019 (2.2 discard/retained catch) indicates that 1915 tonnes of retained catch produced 4213 tonnes of discards, of which a small amount is of commercial species, as A. varidens (3.8 tonnes) and Merluccius polli (153 tonnes). A total of 131 discarded species were identified, with the highest group contribution being fish (70%), followed by crustaceans (20%). The most abundant species in discard weight were Ariomma melanum, Lamprogrammus exutus, Chaunax pictus, Centroscymnus owstonii, Hoplostethus cadenati, Lophius vaillanti, Yarrella blackfordi and Ariomma bondi (all together accounting for 55% of discards). The most frequent species were H. cadenati and L. exutus, discarded in 95% of the analysed fishing hauls. Discards estimations of commercial species obtained through a long-term observers program might result in improving the assessments of main commercial species from Angolan deep sea waters

Análisis de la Distribución Geográfica y Biodiversidad en la Costa Pacífica de Centroamérica

El presente estudio se ha realizado durante la estancia de prácticas del alumno Fernando Miranda Almón en el Centro Oceanográfico de Vigo (IEO) para la obtención del título de Máster Interuniversitario de Biología Marina (Universidades da Coruña, Santiago de Compostela y Vigo). Durante la estancia se integró en el equipo de Pesquerías Lejanas siendo su tutor el investigador D. José Luis del Río Iglesias.Se realiza un estudio de la distribución y biodiversidad de la macrofauna demersal de la costa Pacífica de Centroamérica, cubriendo un amplio rango latitudinal y batimétrico. Los datos fueron obtenidos en la Campaña de Investigación Pesquera CENTROAMERICA-PACIFICO 2010, realizada por el Instituto Español de Oceanografía

An holistic ecological analysis of the diet of Cory's shearwaters using prey morphological characters and DNA barcoding

wledge of the dietary choices and trophic niches of organisms is the key to understanding their roles in ecosystems. In seabird diet studies, prey identification is a difficult challenge, often yielding results with technique-specific biases. Additionally, sampling efforts are often not extensive enough to reveal intrapopulational variation. Immature animals, which may constitute up to 50% of a population, may occupy a significantly different trophic niche to more experienced birds, but this remains largely unexplored. We investigated the diet of Cory's shearwater (Calonectris diomedea) from Selvagem Grande, an island located off the northwest African coast, collecting a total of 698 regurgitate samples over three consecutive breeding seasons. The diet was assessed using two complementary approaches for prey identification: conventional morphological analysis (using fish vertebrae, otoliths and cephalopod beaks) and DNA barcoding of the 16S rRNA mitochondrial gene, in cases where a positive identification could not be retrieved. Species assignments employed BLAST and distance-based methods, as well as direct optimization of the tree length based on unaligned sequences in POY. This method resulted in robust tree estimates and species assignments, showing its potential for DNA barcoding of stomach contents using hypervariable markers such as the 16S. The molecular approach increased taxonomic resolution and revealed an additional 17 taxa. Diet differed significantly according to breeding status, sex, breeding phase (prelaying and chick rearing) and year. Such direct evidence of trophic segregation within the same population has rarely been shown in seabirds and highlights the importance of including such variables in ecosystem-based management approaches

Observations of deep-sea fishes and mobile scavengers from the abyssal DISCOL experimental mining area

Industrial interest in deep-sea mineral extraction began decades ago and today it is at an all-time high, accelerated by global demand for metals. Several seafloor ecosystem disturbance experiments were performed beginning in the 1970’s, including the DISturbance and reCOLonization experiment (DISCOL) conducted in the Peru Basin in 1989. A large seafloor disturbance was created by repeatedly plowing the seafloor over an area of ~ 10.8 km2. Though a number of studies in abyssal mining regions have evaluated megafaunal biodiversity and ecosystem responses, few have included quantitative and detailed data on fishes or scavengers despite their ecological importance as top predators. We used towed camera transects and baited camera data to evaluate the fish community at the DISCOL site. The abyssal fish community was relatively diverse with 16 taxa dominated by Ipnops meadi. Fish density was lower in ploughed habitat during the several years following disturbance but thereafter increased over time in part due to changes in regional environmental conditions. 26 years post disturbance there were no differences in overall total fish densities between reference and experimental areas, but the dominant fish, I. meadi, still exhibited much lower densities in ploughed habitat suggesting only partial fish community recovery. The scavenging community was dominated by eelpouts (Pachycara spp), hermit crabs (Probeebei mirabilis) and shrimp. The large contribution of hermit crabs appears unique amongst abyssal scavenger studies worldwide. The abyssal fish community at DISCOL was similar to that in the more northerly Clarion Clipperton Zone, though some species have only been observed at DISCOL thus far. Also, further species level identifications are required to refine this assessment. Additional studies across the polymetallic nodule provinces of the Pacific are required to further evaluate the environmental drivers of fish density and diversity and species biogeographies, which will be important for the development of appropriate management plans aimed at minimizing human impact from deep-sea mining

Informe de la campaña de investigación pesquera Centroamérica-Pacífico 2010, 10 de noviembre al 16 de diciembre de 2010, B/O Miguel Oliver

Equipo de Pesquerías Lejanas. Centro Oceanográfico de Vigo del IEO

Trophic relationships among pelagic predators of the deep seas of the Madeira Islands

This thesis provides a detailed study of the diet of various procellariiformes using new molecular approaches. Dietary studies remove fundamental blocks to our understanding of the structure of food webs, and provide insights into the demographic regulation of populations and the structuring of communities. The study species were the Band-rumped Storm-petrel (Hydrobates castro), Bulwer’s petrel (Bulweria bulwerii), Cory’s shearwater (Calonectris borealis) and White-faced Storm-petrel (Pelagodroma marina). The breeding colonies of the Madeiran-archipelago are Important Bird Areas (IBA) in the North-Atlantic, but little is known about the predator-prey relationships of its seabird populations. This probably relates to difficulties associated with obtaining robust prey estimates and the need to develop new methodologies to improving the resolution of species identification. Here, new molecular approaches were developed to recover prey from faeces and stomach contents using DNA-barcoding and high-throughput sequencing (HTS). The results obtained show clear improvements to the identification of the diets of procellariiformes, considerably outperforming morphological analysis, and retrieving prey identities from non-invasive faecal remains. Such approaches further showed that sympatric small seabirds of the sub-tropical NE-Atlantic significantly segregated their resources, while showing similar prey types with the species distributed in the Pacific, indicating that these petrels maintain foraging specialization across their distribution range. Foraging efficiency in seabirds has been widely hypothesized to change according to the moon cycle. Predators either optimise foraging during moonlit nights or reduce foraging effort because less accessible prey migrate downward the water column to avoid visual predators. I tested whether prey composition and diversity differ between moon-phases. However, I found no evidence for a significant influence of the moon on the diet of Bulwer’s petrel, contradicting previous ecological assumptions. The results highlight the potential of DNA methodologies to the understanding of marine food webs and predator-prey relationships and will certainly make important contributions to marine community ecology

VERTEBRATE PALEONTOLOGY AND TAPHONOMY OF THE LATE CRETACEOUS (CAMPANIAN) BLADEN FORMATION, BLADEN COUNTY, NORTH CAROLINA

A site recently discovered near Elizabethtown, North Carolina, has produced a wealth of late Cretaceous (Campanian) age vertebrate fossil material revealing a variety of new taxonomic, paleoecologic, and biogeographic information. This site, the Bladen County Landfill Annex (BCLA), has yielded a greater abundance and diversity of vertebrate material than Phoebus Landing, a well-researched site located approximately 7 km (4.35 miles) southeast of Elizabethtown.  Bulk sampling of a bonebed located at the top of the Bladen Formation at the BCLA site yielded a diverse assemblage of fresh water, brackish water, and terrestrial organisms. The fossils from this site exhibit little or no abrasion, implying no transport or a short time and distance of transport. Fossils representing Chondrichthyes, Osteichthyes, Reptilia, Mammalia, and Amphibia were recorded. This fauna allows for regional correlation with Campanian age faunas from the Marshalltown Formation (Ellisdale Site), New Jersey and the Blufftown Formation, Georgia. Of particular note, the BCLA faunal assemblage also exhibits affinities with Campanian age microvertebrate fossil assemblages from the Aguja Formation of Texas, the Mesaverde Formation of Wyoming, the Judith River Formation of Montana, and the Oldman Formation of Alberta, Canada.  M.S