1,721,215 research outputs found
Genomic Landscape of Divergence in Ballan Wrasse (Labrus bergylta) [Dataset]
No full text4 filesThis is the final dataset used in Jansson et al. (2025 study "Genomic landscape of divergence in Ballan wrasse (Labrus bergylta)" published in Molecular EcologyPeer reviewe
Supplemental Material for Martínez et al., 2025
No full text25 filesAlignment of orthologous chromosomes of the two European hake chromosome-level genomes using Minimap2 and pafr package from RPeer reviewe
Study on reproductive potencial of Merluccius merluccius in the Galician shelf
Full text link286 páginasEuropean Commission RASER project "Reproduction and stock evaluatin for Recovery" (Q5RS-2002-01825).
Galicia Government Project XUGA-40201B98Peer reviewe
Bioenergetics approach to fish reproductive potential: case of Trisopterus luscus (Teleostei) on the Galician Shelf (NW Iberian Peninsula)
No full textThe fish species Trisopterus luscus (Linnaeus 1758), commonly known in English as pouting, is a member of the cod family (Gadidae) and it is of major commercial importance to the artisanal fleet of a number of European countries, primarily France, Portugal and Spain. Since the 1960s and 1970s (with average landings of around 3000 t per annum) a slow but steady decrease in catches has been observed on the Galician shelf, down to landings below 1000 t per annum in recent years. This situation is aggravated by the fact that the information available about this species is generally scarce, especially regarding our knowledge of its reproductive biology.
Knowledge of the reproductive biology of a fish species is essential for effective fishery management. There is increasing awareness that the traditional indicators of stock viability are inadequate because the capacity of a population to produce viable eggs and larvae each year is extremely important for stock viability and recovery. Improved estimates of stock reproductive potential should thus lead to improving the current models used in fisheries management.
Histological study of gonads of T. luscus was consistent with asynchronous ovarian development. This study shows that pouting on the Galician shelf presents a protracted spawning season, from January to May, with a peak of spawning activity in February, a month when female pouting release a batch almost every day. Length-at-maturation, 150.6 mm, was lower than previously estimated in other studies, and it seems to be in concordance with the established minimum legal size, 200 mm. The development of the pelagic eggs and hatched larvae has been described for the first time ever in this study. This has also been the first natural spawning experience in captivity for this species.One of the most important findings in this study is that pouting exhibits determinate follicle recruitment. However, the possibility of an indeterminate period of follicle recruitment in response to surplus energy is also likely to occur. Maternal effects in potential and batch fecundity are clearly manifested through positive allometric coefficient of fecundity-female size relationships.
Energy reserves in pouting females are mainly associated to the lipids stored in the liver. Water content appeared to be a
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useful index in order to obtain very accurate predictions of energy density, particularly for gonads and the liver. Condition indices, both the common ratio index and the residual index, are suitable to analyze nutritional status of fish, since they reflect changes in energy content and proximate composition in the different tissues studied. The seasonality of energy reserves was clearly detected and is closely related to the sexual cycle, indicating that pouting females display a period of energy storage, mainly through lipid deposition in the liver. Therefore, pouting should be considered a capital rather than an income breeder, as the fuel for reproduction comes essentially from stored energy.
Reproduction in T. luscus is financed from stored energetic capital, but energetic provision through concurrent feeding during reproduction may also contribute to egg production, i.e. pouting exhibits a mixture of determinate/indeterminate fecundity and capital/income breeding strategies.
Individual female size influences reproductive biology at different levels, as discussed previously in this chapter: timing and length of spawning and fecundity (potential and batch). Therefore, it is not surprising that the simulation model has verified that a population biased towards larger fish can produce a considerably higher TEP than a population with the same SSB but biased towards smaller females. These huge differences clearly support the inadequacy of the assumption of direct proportionality between egg production and Spawning Stock Biomass. Additionally, and as shown in our study, larger fish not only contribute disproportionally to SRP in terms of quantity but also of quality.
Consequently, effective and sustainable fishery management requires considering several aspects of fish reproductive strategies to better preserve a stock’s reproductive potential.his research was supported by the Spanish Ministry of Science and Innovation under the project ECOPREST (VEM2003-20081-C02-02). The experimental procedure was developed under the coverage of Project DETEPRE (08MMA010402PR)."Peer reviewe
Fishery ecology of the freshwater fishes in the Lake Nicaragua. Reproduction and management of Brycon guatemalensis
No full textThe freshwater bodies are very dynamic systems, and have been the first aquatic
ecosystems susceptible to receive the direct impact of human activities, becoming very
vulnerable ecosystems. The Lake Nicaragua has been recognised as a continental water body
with an important source of fish living resources for the fishery sector. In addition, its
dimension is very attractive for the development of aquaculture activities. However, the
exploitation level of fishing resources in the lake has lead to an overexploitation of some
species already included in UICN red list, while others are in risk of being overexploited if
management measures are not taken. Studies on species diversity in the lake defined two
demersal fish habitats: the “shallow benthic” habitat, which has a higher index of species
diversity and the “deep benthic” habitat with lower diversity index.
The landings data series do not allow ascertaining the catches composition. Hence, any
evaluation of the fish exploitation pattern in the Lake Nicaragua derived from landings record
is imprecise. Besides, the large gap on knowledge of many other important biological
parameters of the fish species - the dynamic of reproductive behaviour of the population, the
reproductive cycle, spawning ground, egg production and the maternal features affecting
reproductive output and fitness- prevents the implementation of management actions directed
towards the conservation of the lake stock reproductive potential, such as regulations on
closing season and/or areas, and minimum landing sizes. This study, besides providing
information about actual state of distribution and abundance of Amphilophus citrinellus,
Hypsophrys nicaraguensis, Parachromis managuensis, and Brycon guatemalensis, provides
information of the reproductive strategy of B. guatemalensis and proposes some management
alternatives based on its biological features.The present study was conducted along the eastern part of the Lake Nicaragua and
showed that even all the species studied were widely distributed in this area, species
abundance varied geographically (zones: northwest, central and southeast) and vertically
(depth: from shallow to deeper areas). The patterns of abundance of cichlid (A. citrinellus, H.
nicaraguensis and P. managuensis) are affected by spatial (zones) and environmental factors
as the vertical profiles (depth), whereas in B. guatemalensis was also affected by seasons of
the year, i.e., dry and rainy season. Cichlids were more abundant in shallow waters and in the southeast zone, whereas B. guatemalensis larger abundances were found in the southeast and
northwest side. Similarly, the size distribution pattern was influenced by both latitude and
vertical profiles. Overall, larger fishes are found in the southeast and to a lesser extent in the
central zone of the lake, whereas in the northwest are smaller. Furthermore, larger fish are
found in relative deeper waters.
The reproductive studies on B. guatemalensis using histological procedures showed that
the oocytes final maturation ended with the migration of the germinal vesicle to the animal
pole, without oocyte hydration, and oocytes being surrounded by mucus indicative of eggs
adhesiveness. The species presented a protracted spawning season that lasted 8 months. Both
small and large females started the spawning activity in July, but spawning asynchrony
occurred between female sizes as spawning season progressed.Based on histological procedures, the female length at 50% maturity of B. guatemalensis
was estimated in 27.3 cm, which largely differed from the ones previously reported based on
the gonad macroscopic observations. The present study indicated that B. guatemalensis has
determinate fecundity and presented group-synchronous ovarian organization. The potential
annual fecundity of the species showed that this allometrically increased with female size, and
that larger females produced larger eggs. Nonetheless, egg size decreased as spawning season
progressed.
Gillnet selectivity studies were performed on four species (A. citrinellus, H.
nicaraguensis, P. managuensis, and B. guatemalensis) and selectivity was quite different
among species, partly reflecting growth patterns. The absence of larger and smaller fishes was
notorious in the catches. The absence of larger fish likely indicated the expected maximum
size of each species within the lake ecosystem, while the minimum size captured may be
attributed to the fish shape and/or different behaviour of the life stages of each species. The
most vulnerable fraction of the population of cichlids was males, and females in the case of B.
guatemalensis, particularly during reproductive periods. The sex ratio of each species
obtained in the present study very likely is similar to those in the catches in a routine fishing
operations performed by the fishers in the lake.The establishment of a minimum landing size (MLS) is one of the most common
management measures, particularly in data limited stocks exploited by the small-scale
fisheries, and often this measure is reinforced with regulations on fishing gears mesh size.
Generally, legal mesh size is determined combining gear selectivity and length-at-50%
maturity of the target species. The main objective of this management rule is the protection of
the immature or juvenile components of the stock, a measure often considered enough to
ensure the sustainability of the fishery. However, reproductive studies have evinced that
larger mature females are more productive than smaller mature ones, thus, the catches of
larger fish could also lead to a significant reduction of stock productivity. In this study, we
analyzed the impact of gillnet selectivity on B. guatemalensis in relation to ontogenic
maturation, reproductive phase, and reproductive potential. Results showed that juveniles and
recruit spawners are the most vulnerable to the 75 mm mesh-size, whereas the majority of the
spawning stock biomass (SSB), and particularly those with higher reproductive potential, are
highly vulnerable to the 100 mm mesh size, due to the interaction between the female lengthmesh
relationship and the seasonal behaviour pattern of those females. Based on these results,
a MLS of 30 cm is proposed as management measures to protect the immature or juvenile
components of the stock, and to increase egg production of the SSB and reduce the fishing
mortality of young females we recommended the use of 100 mm mesh size of net for fishing
operation in the Lake Nicaragua.Esta tesis doctoral fue posible desarrollarla gracias al apoyo de la Agencia Española de
Cooperación Internacional para el Desarrollo a través de una beca de investigaciones predoctorales
MAEC-AECID de dos años y gracias al apoyo del Grupo de Ecología Pesquera del
IIM-CSIC durante un periodo similar.Peer reviewe
Distribution, abundance and biomass trends of the genus Sebastes on Flemish cap (division 3M)
No full text12 páginas, 11 figuras.-- Scientific Council MeetingIn recent years raffish biomass has decreased substantially, at the same time as catches have increased considerably. The redfish resource is managed like a single stock, though it is formed of three species, Sebastes marinas, S. mentella and S. fasciatus are different, not only in their abundance, but also in their distribution and behaviour. A correct analysis should consider these aspects.
In 1988 the EEC started bottom trawl surveys on Flemish Cap. In this paper, redfish distributions obtained in the last five years, and a year class analysis are presentedPeer reviewe
La pesca en el futuro de la gestión y gobernanza marina: ¿Puede la pesca gestionarse de forma aislada?
No full text2 pagesLos mares de nuestro planeta aportan un conjunto de servicios ecosistémicos fundamentales para el desarrollo humano, entre los que destaca, sin duda y de manera histórica, la actividad pesquera como fuente de alimento saludable y sostenible (más de 3.000 millones de personas dependen de los océanos como fuente principal de proteínas) y es fuente de riqueza para gran parte de las comunidades costeras. Por ello, desde hace décadas conocemos que la gestión prudente de los recursos que la gestión prudente de los recursos pesqueros es un paso imprescindible para alcanzar un futuro sostenible.Peer reviewe
The Recovery Plan and Resilience of the Blue Economy: Complementary Plan for Marine Sciences in Spain
No full text11th edition Bussiness 2 Sea, 16-18 November 2021The EU blue economy encompasses all industries and sectors related to oceans, seas and coasts, whether they are based directly in the marine environment (e.g., shipping, seafood, energy generation) or on land (e.g., ports, shipyards, coastal infrastructures). According to the most recent blue economy report, the traditional sectors of the blue economy provide 4.5 million direct jobs and generate over 650 billion euro in turnover. In May, the European Commission presented the communication “A new approach for a sustainable Blue Economy in the EU”. A sustainable blue economy is essential to achieving the objectives of the European Green Deal and ensuring a green and inclusive recovery from the pandemic. This conference will discuss the European policies and initiatives for a sustainable blue economy transformation with examples of reforms and investments that the Member States are planning in their national resilience and recovery plans approaching the blue economyN
Sexual Maturity and Spawning Biomass of the Cod Stock on Flemish Cap (Division 3M)
No full text9 páginas, 3 figuras, 5 tablas.-- Scientific Council MeetingLength and age at maturity of the Flemish Cap female cod has been determined by an histological method since 1990 at summer, when the EU-survey is carried out. The method uses cod ovaries in the cortical alveoli stage as an index of the onset of the oocyte development for the next breeding season, whereas the presence of postovulatory follicles in the ovaries shows the already spawned females (Zamarro et al., 1993)Peer reviewe
Osteological differences in species of Sebastes on Flemish Cap
No full text9 páginas, 2 tablas, 6 figuras.-- Scientific Council Meetin
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