Julio Valeiras

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• MS
• Researcher at Instituto Español de Oceanografia

Long-term conservation of marine resources depends on the availability of data to adequately assess fish stocks, the environmental state and the impact of fishing activity on marine ecosystems. In recent years, electronic monitoring (EM) has developed significantly as a tool to provide data on fishing activity and catches. In this context, the ques...

We describe a scientific program to reduce, and improve scientific knowledge of, bycatch of cetaceans and other Protected, Endangered and Threatened (PET) species uring fishing activities, thus responding to the requirements of several EU directives and regulations, as well as the EU request on "emergency measures to prevent the accidental capture...

The Argonautoidea is a monophyletic superfamily of pelagic incirrate octopods primarily distinguished by an unusual means of copulation where a sexually modified arm, or hectocotylus, is detached and transferred from dwarf males to the female. Males of the seven-arm octopus Haliphron atlanticus are scarcely observed and little is known about their...

Long-term conservation of marine resources depends on the availability of data to adequately assess the environmental state and the impact of fishing activity on fish stocks and the marine ecosystem. The on-board observers have been the main data source to supply the key fishing catch information from commercial fishing boats. We have launched a p...

It is widely known that to achieve sustainable fishing is necessary measures to monitoring control and surveillance (MSC) to ensure the compliance of politics to protect and conserve marine life and oceans. Recently, the development of new technologies of electronic monitoring (EM) have involved a new possibility to authorities and research institu...

Using information obtained from VMS data helps design effective and efficient electronic monitoring sampling based on the combination of increased fishing pressure and increased catches of each target species according to management interest.

Knowledge of marine biodiversity is vital for developing appropriate conservation policies. In the current Information Age, data shared by citizens in social networks are a cost-effective alternative to complement on-going marine biodiversity monitoring programs, as well as to understand human interactions with the natural environment from a curren...

The Spanish otter bottom trawl fishery operating in NEAFC regulated waters, fishes in the 'Great Sole' fishing ground (ICES subareas 6 and 7). This mixed fishery targets megrims, monkfish and hake. Due to the discards rates of unwanted species multiannual research project was devoted to design technical solutions and a more efficient use of fishing...

It is widely accepted that discards are a waste of resources from the perspective of the exploited stocks and from a macro-economic human perspective. There is thus a strong commitment to reduce the discards of European fisheries by enforcing the Landing Obligation for the unwanted catch. The European Common Fisheries Policy (CFP) aim to eliminate...

Long term success of a sustainable management fishing depends on obtaining more data of scientific and technical information. Remote electronic monitoring (REM or simply EM) systems have been considered a robust and potential tool to obtain a fully documented fisheries in the framework of Common Fishery Policy (CFP). Moreover, European Fisheries Co...

A key challenge for the sustainability of fisheries targeting commercial species in Europe in the context of ecosystem-based management is the mortality of protected, endangered and threatened (PET) species such as cetaceans due to fishery bycatch. Such species are vulnerable to bycatch mortality due to their low fecundity and other life history tr...

Mitigation measures and improvement of scientific knowledge to reduce accidental captures of cetaceans during fishing activities are the focus of regulations that respond to the need to adopt measures based on the EU request on "emergency measures to prevent the bycatch of cetaceans in the northeast Atlantic”. These emergency measures are aimed at...

Fishery bycatch mortality is generally considered to be the main threat to cetaceans in European Atlantic waters. The marine waters in the Northwest of the Iberian Peninsula are among the richest in fishery resources in Europe and, consequently, they are also very important for fisheries. Analysis of cause of death and life history data from strand...

Several fisheries have been flagged for evidence of high dolphin bycatch rates. Some of the pelagic trawl fisheries operating off western Europe captured short-beaked common dolphins in unsustainable rates. Reducing the incidental bycatch of common dolphins at northwestern Iberian waters is an objective for European Commission to not exceed the max...

The United Nations (UN) Decade of Ocean Science highlights a need to improve the way in which scientific results effectively inform action and policies regarding the ocean. Our research contributes to achieving this goal by identifying practical actions, barriers, stakeholder contributions and resources required to increase the sustainability of ac...

Despite being landed in commercial cephalopod fisheries, species of Alloteuthis are not yet well defined, with A. subulata and A. media often confused. DNA barcoding combined with morphometric analyses has begun to clarify the distinction between these two morphologically similar species but has been limited in its geographic coverage to date. Here...

WGCEPH worked on six Terms of Reference. These involved reporting on the status of stocks; reviewing advances in stock identification, assessment for fisheries management and for the Marine Strategy Framework Directive (MSFD), including some exploratory stock assessments; reviewing impacts of human activities on cephalopods; developing identificati...

With the aim of maintaining or obtaining good environmental status in the Northeast Atlantic and northern Mediterranean Sea, the European Marine Strategy Framework Directive (EU-MSFD) came into force in 2008. All EU Member States (MS) have the task of assessing the current state of their adjacent waters to guarantee sustainable use of marine resour...

In the Atlantic waters of Northwest Europe, in the ‘Grand Sole fishing ground’ (area ICES7), a bottom trawling fishery operates targeting demersal species, mainly megrim, monkfish and European hake. Due to the multi-specific nature of this mixed fishery there is a need to develop technical solutions and more selective fishing gears to minimize disc...

The red sea cucumber, Parastichopus tremulus (Holothuroidea), inhabits in the northeast Atlantic, from north European waters of Norway and Iceland to southern Europe, with occasional records in the Canary Islands (Schagerström and Sundell., 2021). P. tremulus can be found at depths from 20 m to 1900 m, inhabiting muddy floors, mainly. This species...

Fishing bycatch mortality is one of the greatest threats to cetaceans worldwide. Approximately 500,000 marine mammals are accidentally caught each year by different fisheries around the world. Over the last decade, a concerning increase in the number of strandings with bycatch evidences has been recorded in the Bay of Biscay and the Iberian Coast M...

It is widely accepted that discards are a waste of resources from the perspective of the exploited stocks and from a macro‐economic human perspective. There is thus a strong commitment to reduce the discards of European fisheries by enforcing the landing obligation of the unwanted catch. The European Common Fisheries Policy (CFP) aim to eliminate t...

During the last few years an increasing trend on landings of sea cucumbers indicates that these species have been increasingly valued by the fishing sector, beginning to be species of commercial interest for the trawl fisheries. In the past, sea cucumbers were a bycatch species that had been discarded overboard because of the lack of market. These...

Elasmobranchs are marine species with a global decrease in their fishing abundance in recent decades, largely due to overfishing. Several species, such as rays and skates, present difficulties in morphological identification, which leads to misidentifications. The common skate, Dipturus batis, is currently listed as "critically endangered" by the I...

Citation: Valeiras, J.; Vilas, N.; Abad, E.; Fernández-Franco, J.C.; Barreiro, M.; Saavedra, C.; Velasco, E. Abstract: The selective retention of fish is a consequence of size and species-dependent fish behaviour during the trawling process. The observation of fish reactions to trawl gear is critical to understanding the behavioural mechanisms resp...

The veined squid, Loligo forbesii Steenstrup, 1856, occurs at the European Shelf areas including the Azores and represents a valuable resource for the European commercial fishery in the North East Atlantic. However, very little is known about its population structure and phylogeography. This lack of knowledge also impedes the development of sustain...

Recent review papers have addressed progress in stock assessment and forecasting for fished cephalopods but there remains a need to develop appropriate management for many European cephalopod fisheries, given that cephalopods are not quota species under the Common Fisheries Policy. Here we briefly review potential barriers to sustainable fishing an...

In past centuries, the impacts on cephalopods from humankind were negligible. The first documented small-scale exploitation of cephalopods occurred in the Mediterranean and Asia. Between 1950-2019, global cephalopod catches increased by about an order of magnitude, from 0.5 million tones to a peak of 4.85 million tons. The human impact on the ocean...

Knowledge of stock structure is a priority for effective assessment of commercially-fished cephalopods. Loligo forbesii squid are thought to migrate inshore for breeding and offshore for feeding and long-range movements are implied from past studies showing genetic homogeneity in the entire neritic population. Only offshore populations (Faroe and R...

On the 1st of January 2014, the European Union introduced a phased discard ban or “Landing Obligation” for regulated species, as part of Common Fisheries Policy (CFP) Basic Regulation (Article 15). Today, in the post-Landing Obligation world, it may appear that a report on discard survival has little relevance. However, The Landing Obligation polic...

Underwater video cameras are a highly versatile survey solution for marine fisheries research. The POLYBIUS2020 is a system specially designed to be used as a tool for video recording inside towed fishing gears. Its design allows for rapid installation onboard commercial fishing vessels as well as for quick reconfiguration and battery replacement....

Common dolphins (Delphinus delphis) are top predators, feeding on a wide variety of prey species, several of which are also targeted by fisheries. The last remaining healthy group of the endangered Mediterranean common dolphin subpopulation is located in the Alboran Sea. Their feeding grounds overlap with the fishing grounds of trawlers targeting E...

This policy brief aims at providing a concise summary of scientific information that can help managers and policy-makers make informed decisions about the sustainability of cephalopod fisheries. It contains 10 important current issues affecting cephalopods and proposed possible solutions regarding the following topics: natural highs and lows in abu...

Few studies examined species or ecosystem dynamics on seamounts/banks. The Galicia Bank (GB), the deepest marine Special Area of Conservation in the Spanish Natura 2000 network, is considered a conservation priority because of its highly vulnerable habitats, such as cold-water and bamboo corals. The biological conditions and population structure of...

Effective conservation and management measures are needed to face the unprecedented changes that marine ecosystems, and particularly marine megafauna, are suffering. These measures require the identification of high-value biodiversity areas (HVBAs) which in turn require the identification of the essential ocean variables (EOVs) that shape the envir...

The Working Group on Cephalopod Fisheries and Life History (WGCEPH) improves knowledge about and the assessment of cephalopods as an exploited resource. WGCEPH report provides information on status and trends in cephalopod stocks; preliminary assessments of selected stocks update information on life history parameters; social and economic profile...

The MARTEC18 Conference “International Conference on advances in marine technologies applied to discard mitigation and management” was held from May 2nd to 5th, 2018 in Vigo. MARTEC18 welcomed 118 attendees and 48 worldwide speakers from 17 Research Centers, Universities, 3 Business Companies and representatives from FAO, regional, national and Eur...

Monitoring plays a key role in all aspects of fisheries management, including those related to sustainable management of resources, the economic performance of the fishery, and the distribution of benefits from the exploitation of the fishery and environment. In this manuscript, an electronic device (the iObserver) is described, which aims to impro...

Most fisheries management systems rely on a set of regulatory measures to achieve desired objectives. Controls on catch and effort are usually supplemented with gear restrictions, minimum landing sizes, and in the framework of the new common fisheries policy, limitation of discards and by-catch. However, the increasing use of spatial management mea...

The basking shark Cetorhinus maximus is a plankton feeding shark (Lamniformes: Cetorhinidae) distributed worldwide in boreal to warm temperature waters. The presence in Spanish and Portuguese Iberian waters is poor documented although this species occurs and it is well-known by fishermen. In this work we present data on basking shark presence in 30...

In the last few decades, there has been a remarkable development of niche models to help understand the ecological response of species to current rapid environmental changes. In the present study, we applied niche modelling to the megafauna community of shelf waters of the northwestern (NW) and northern Iberian Peninsula in order to analyse the coe...

To assess the likely economic outcomes to fishing fleets of the Landing Obligation (LO), bioeconomic models covering seven European fisheries, ranging from the North East Atlantic to the Mediterranean, have been applied to estimate the economic performance of fleets before and after implementing the LO. It is shown that for most of the analysed fis...

The purpose of this chapter is to discuss challenges that the EU Landing Obligation presents to the onboard handling of unwanted catches and how vessel layout modifications can be applied to meet these challenges. The key challenge the industry is facing is having to bring ashore catches of little or no value, which requires significant effort to h...

In the last few decades, there has been a remarkable development of niche models to help understand the ecological response of species to current rapid environmental changes. In the present study, we applied niche modelling to the predator community of the northern and northwestern shelf waters of the Iberian Peninsula to analyse the coexistence of...

Survival experiments were carried out during the DESCARSEL0917 research survey along the continental shelf and upper slope of Galicia. The objective was to determine survival rates of sea cucumbers Parastichopus tremulus and P. regalis to the processes of discarding and handling in trawl fishing. The individuals who arrived with signs of vitality t...

Monitoring and assessment of the status of marine mammal populations is a requirement of the European Marine Strategy Framework Directive (MSFD). Due to the difficulty of collecting data in the marine environment and because many populations of these highly mobile species inhabit waters of several Member States, monitoring of marine mammals is part...

Discard management needs to draw on scientific research and advice, usually supported by specific statistical modeling analysis. A wide range of statistical analysis methods were applied to fishery data in an attempt to distinguish factors that influence the species discard composition. While such approaches are important, they are still incomplete...

The goblin shark Mitsukurina owstoni Jordan, 1898 (Chondrichthyes: Lamniformes:Mitsukurinidae) is a poorly known deepwater shark. The species is distributed worldwide in deep waters down to 1500 m and most records are at upper slopes, submarine canyons and ridges. This shark is very characterized by a long and well depressed paddle-like snout, slen...

The Spanish multidisciplinary survey PELACUS is carried out annually to study pelagic marine ecosystem and evaluate fishing resources of the North and Northwest shelf waters of the Iberian Peninsula. Linear transects perpendicular to the coast distant 8 nm each and up to the 1000 m isobath are prospected acoustically at a speed of 10 knots between...

Studies on the spatial distribution patterns of decapods crustacens in the Galician and Cantabrian continental shelf are scarce. Decapods are the second group in abundance after fish in the area, and it is a target group in fisheries. In the framework of the Ecosystem approach fisheries management, it is necessary to increase knowledge on the ecolo...

This study provides an analysis of the main existing technical measures in the Mediterranean, in view of the new CFP objectives and taking into account the regional aspects of the Mediterranean management system which is based mainly in technical measures. The analysis identifies the types of technical measures and proposed which of them should be...

Common dolphins (Delphinus delphis) are one of the most abundant species of small cetacean in Northeast Atlantic Ocean and the most abundant in Atlantic shelf waters of the Iberian Peninsula. However, the abundance, distribution and population trends in the recent years of this species are poorly known, but such information is needed to develop pop...

El área de estudio abarcada por este “Atlas de los descartes de la flota de arrastre y enmalle en el Caladero Nacional Cantábrico-Noroeste” son las comunidades autónomas de Galicia y Principado de Asturias. Se presenta la información actualizada de los métiers en los que se incluyen las pesquerías de arrastre y enmalle del caladero Cantábrico-Noroe...

Visual Guide of Demersal Species in continental shelf of north and nortwest Spanish wateres: 2. Invertebrates

Visual Guide of Demersal Species in continental shelf of north and nortwest Spanish wateres: 1. Fish

The Galicia Bank (NE Atlantic, 42°67′N–11°74′W) is an isolated seamount, near NW Spain, a complex geomorphological and sedimentary structure that receives influences from contrasting water masses of both northern and southern origins. Within the project INDEMARES, three cruises were performed on the bank in 2009 (Ecomarg0709), 2010 (BanGal0810) and...

SEA TURTLES IN THE GALICIAN COAST BETWEEN XVIII CENTURY AND 2013. A review of sea turtles recorded on the Galician coast until 2013 is performed, totalling 582 records: 303 Dermochelys coriacea, 245 Caretta caretta, 12 Chelonia mydas, 3 Eretmochelys imbricata, 2 Lepidochelys kempii and 17 unidentified. For the first two species the annual, monthly...

To reduce the practice of discarding commercially fished organisms, several measures such as a discard ban and extra allowances on top of landings quotas (“catch quota”) have been proposed by the European Commission. However, for their development and successful implementation, an understanding of discard patterns on a European scale is needed. In...

A first growth function was estimated for the South Atlantic swordfish stock. A total of 406 anal fins were collected from 2006 to 2013. Fins were classified into three types and the most common, type A, was selected. Biometric relationships among several ray section measurements and lower jaw fork length were analysed. A detailed methodological de...

El Banco de Galicia es un monte submarino profundo localizado al noroeste de la península ibérica, a 180 kilómetros de la costa gallega. Su cima se encuentra entre los 650 y los 1.500 metros de profundidad. Sus laderas, de elevadas pendientes, caen desde esta cima hasta las llanuras abisales situadas a 4.000 metros de profundidad. Esta montaña subm...

Discards refer to the part of the catch not retained on board during commercial fishing operations, but returned to the sea. The proposed European Union Common Fisheries Policy reform, to be implemented in 2014, sets out a gradual elimination of discards by reducing unwanted catches and ensuring that all catches are landed. To develop successful di...

The seven-arm octopus Haliphron atlanticus Steenstrup 1861 belongs to one of the four families of Argonautoidea Naef, 1912, which are primarily distinguished by an unusual means of copulation which involves transferring a detached hectocotylus from the male to the female. H. atlanticus coils the hectocotylus into a sac beneath the right eye. Althou...

Volunteering and custody of the nesting Kentish plover (Charadrius alexandrinus) in Nigrán (Pontevedra) in 2012. Application of the "Conservation Plan of Kentish plover in Galicia". On June 16th, 2012 we found a Kentish plover nest in Playa America. In a joint action by SGHN and CEMMA and with logistical support and advice of ANABAM, it was decided...

Cephalopod species are an important marine resource in the Northern Spain fisheries. Several species are landed by both commercial and artisanal fleets, and landings from the latter have been relatively poorly documented in the past (Pierce et al., 2010). The bottom trawl survey on the Northern Spanish Shelf (DEMERSALES) aim to provide data and inf...

We identified 11 cephalopods collected by GOC73 otter-trawling belonging to 8 species. Except for Todarodes sagittatus all specimens are first records for Galicia Bank, a large seamount located at 150 miles far from the west coast of Galicia (Spain). Species Graneledone verrucosa (Verrrill, 1881) Opisthoteuthis grimaldii Joubin, 1903 Stauroteuthis...

It has been widely acknowledged that fishery discard practices constitute a purposeless waste of valuable living resources, which plays an important role in the depletion of marine populations. Furthermore, discarding may have a number of adverse ecological impacts in marine ecosystems, provoking changes in the overall structure of trophic webs and...

Un nouveau signalement de deux serpentons à nez long Ophisurus serpens est rapporté dans les eaux de Galice (NO Espagne). Cette espèce tropicale est rare et encore mal connue dans les eaux atlantiques européennes. Ce travail confirme sa présence dans les eaux galiciennes et établit le record géoréférencé le plus au nord de O. serpens en Atlantique...

Nowadays many different marine animals are being tagged. This book summarizes recent tagging programs carried out by the Spanish Institute of Oceanography (IEO). Although the objectives of these various studies mainly depend on the species and each project in particular, the general aim is to better understand the biology and ecology of these anima...

SUMMARY A total of 130 dorsal fin spines from western Mediterranean Atlantic little tuna were analyzed from 2003 to 2006 for ageing and growth studies. The length of the aged individuals ranged from 48 to 84 cm. Fish ages ranged 1 to 5 years old and the mean lengths by age were calculated for males and females. Growth parameter estimates were calcu...

2 SUMMARY A total of 755 anal fins from western Mediterranean swordfish were analyzed from 2003 to 2005 for ageing and growth studies. The lower jaw fork lengths of the aged individuals ranged from 54 to 186 cm for the males and from 55 to 223 cm for the females. Fish ages ranged 0 to 10 years old and the mean lengths by age were calculated for mal...

A total of 450 anal fin spines from North Pacific swordfish were analyzed from years 2005 to 2006 for ageing and growth studies. The lower jaw fork lengths of the aged individuals ranged from 74 to 235 cm for the males and from 71 to 294 cm for the females. Fish ages ranged 0 to 13 years old and the mean lengths by age were calculated for males and...