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1.
Conserv Biol ; 36(2): e13821, 2022 04.
Artículo en Inglés | MEDLINE | ID: mdl-34405455

RESUMEN

The unlimited economic growth that fuels capitalism's metabolism has profoundly transformed a large portion of Earth. The resulting environmental destruction has led to an unprecedented rate of biodiversity loss. Following large-scale losses of habitats and species, it was recognized that biodiversity is crucial to maintaining functional ecosystems. We sought to continue the debate on the contradictions between economic growth and biodiversity in the conservation science literature and thus invite scholars to engage in reversing the biodiversity crisis through acknowledging the impacts of economic growth. In the 1970s, a global agenda was set to develop different milestones related to sustainable development, including green-blue economic growth, which despite not specifically addressing biodiversity reinforced the idea that economic development based on profit is compatible with the planet's ecology. Only after biodiversity loss captured the attention of environmental sciences researchers in the early 2000s was a global biodiversity agenda implemented. The agenda highlights biodiversity conservation as a major international challenge and recognizes that the main drivers of biodiversity loss derive from economic activities. The post-2000 biodiversity agendas, including the 2030 Agenda for Sustainable Development and the post-2020 Convention on Biological Diversity Global Strategy Framework, do not consider the negative impacts of growth-oriented strategies on biodiversity. As a result, global biodiversity conservation priorities are governed by the economic value of biodiversity and its assumed contribution to people's welfare. A large body of empirical evidence shows that unlimited economic growth is the main driver of biodiversity loss in the Anthropocene; thus, we strongly argue for sustainable degrowth and a fundamental shift in societal values. An equitable downscaling of the physical economy can improve ecological conditions, thus reducing biodiversity loss and consequently enhancing human well-being.


Trascendiendo las Estrategias de Crecimiento Capitalista para la Conservación de la Biodiversidad Resumen El crecimiento económico ilimitado que alimenta el metabolismo del capitalismo ha transformado profundamente una gran parte del planeta Tierra. La destrucción ambiental resultante ha traído como consecuencia una tasa sin precedentes de pérdida de diversidad biológica. Después de la pérdida a gran escala de hábitats y especies, se reconoció que la biodiversidad es crucial para mantener el funcionamiento de los ecosistemas. En este articulo buscamos seguir con el debate sobre las contradicciones entre el crecimiento económico y la biodiversidad en la literatura de las ciencias de la conservación y así invitar a los académicos a participar en la reducción de la crisis de biodiversidad dando a conocer los impactos del crecimiento económico. En la década de 1970, se estableció una agenda global para desarrollar diferentes metas relacionadas con el desarrollo sustentable, incluyendo el crecimiento económico verde y azul, la cual a pesar de no mencionar específicamente la biodiversidad reforzó la idea de que el desarrollo económico basado en ganancias es compatible con la ecología del planeta. Fue solamente después de que la pérdida de biodiversidad captó la atención de los investigadores de las ciencias ambientales a principios de la década de los 2000 que se implementó una agenda para la diversidad biológica. La agenda resalta que la conservación de la biodiversidad es un gran reto internacional y reconoce que las pincipales causas de la pérdida de la diversidad biológica derivan de las actividades económicas. Las agendas para la biodiversidad creadas después del 2000, incluyendo la Agenda 2030 para el Desarrollo Sustentable y el Marco de Trabajo de la Estrategia Mundial de la Convención sobre la Diversidad Biológica posterior a 2020, no consideran los impactos negativos de las estrategias para la biodiversidad orientadas por el crecimiento. Como resultado, las prioridades de la conservación mundial de la biodiversidad están gobernadas por el valor económico de la biodiversidad y la supuesta contribución que tiene para el bienestar de las personas. Una gran cantidad de evidencia empírica muestra que el crecimiento económico ilimitado es el principal conductor de la pérdida de diversidad biológica en el Antropoceno; por lo tanto, abogamos fuertemente por un decrecimiento sustentable y un cambio fundamental en los valores sociales. Una reducción equitativa de la economía física puede mejorar las condiciones ecológicas, reduciendo así la pérdida de biodiversidad y mejorando como consecuencia el bienestar humano.


Asunto(s)
Capitalismo , Ecosistema , Biodiversidad , Conservación de los Recursos Naturales/métodos , Desarrollo Económico , Humanos
2.
Sensors (Basel) ; 20(6)2020 Mar 19.
Artículo en Inglés | MEDLINE | ID: mdl-32204330

RESUMEN

During the past decades, the composition and distribution of marine species have changed due to multiple anthropogenic pressures. Monitoring these changes in a cost-effective manner is of high relevance to assess the environmental status and evaluate the effectiveness of management measures. In particular, recent studies point to a rise of jellyfish populations on a global scale, negatively affecting diverse marine sectors like commercial fishing or the tourism industry. Past monitoring efforts using underwater video observations tended to be time-consuming and costly due to human-based data processing. In this paper, we present Jellytoring, a system to automatically detect and quantify different species of jellyfish based on a deep object detection neural network, allowing us to automatically record jellyfish presence during long periods of time. Jellytoring demonstrates outstanding performance on the jellyfish detection task, reaching an F1 score of 95.2%; and also on the jellyfish quantification task, as it correctly quantifies the number and class of jellyfish on a real-time processed video sequence up to a 93.8% of its duration. The results of this study are encouraging and provide the means towards a efficient way to monitor jellyfish, which can be used for the development of a jellyfish early-warning system, providing highly valuable information for marine biologists and contributing to the reduction of jellyfish impacts on humans.


Asunto(s)
Aprendizaje Profundo , Ecosistema , Monitoreo del Ambiente , Escifozoos/fisiología , Animales , Humanos , Tiempo
3.
Proc Biol Sci ; 282(1799): 20142336, 2015 Jan 22.
Artículo en Inglés | MEDLINE | ID: mdl-25621336

RESUMEN

The effects of bottom trawling on benthic invertebrates include reductions of biomass, diversity and body size. These changes may negatively affect prey availability for demersal fishes, potentially leading to reduced food intake, body condition and yield of fishes in chronically trawled areas. Here, the effect of trawling on the prey availability and diet of two commercially important flatfish species, plaice (Pleuronectes platessa) and dab (Limanda limanda), was investigated over a trawling intensity gradient in the Irish Sea. Previous work in this area has shown that trawling negatively affects the condition of plaice but not of dab. This study showed that reductions in local prey availability did not result in reduced feeding of fish. As trawling frequency increased, both fish and prey biomass declined, such that the ratio of fish to prey remained unchanged. Consequently, even at frequently trawled sites with low prey biomass, both plaice and dab maintained constant levels of stomach fullness and gut energy contents. However, dietary shifts in plaice towards energy-poor prey items were evident when prey species were analysed individually. This, together with a potential decrease in foraging efficiency due to low prey densities, was seen as the most plausible cause for the reduced body condition observed. Understanding the relationship between trawling, benthic impacts, fish foraging and resultant body condition is an important step in designing successful mitigation measures for future management strategies in bottom trawl fisheries.


Asunto(s)
Conducta Alimentaria , Explotaciones Pesqueras/métodos , Peces/fisiología , Animales , Conservación de los Recursos Naturales , Dinámica Poblacional
4.
Mar Environ Res ; 199: 106618, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38959782

RESUMEN

The Mediterranean is recognized as a climate change hotspot, with ongoing warming anticipated to impact its habitats and their associated fish fauna. Among these habitats, the seagrass Posidonia oceanica stands out as a foundational species, critical for the stability of coastal fish communities. However, our understanding of climate change consequences on P. oceanica associated fish fauna to date remains limited in part due to a lack of long-term data. This study aimed to highlight potential climate change risks to fish species associated with Posidonia, integrating data on species' thermal envelopes with their habitat and depth preferences into a climate change risk index. Specifically, 9 species, including three pipefish and several wrasse species of the genus Symphodus, emerged as being at higher potential risk from climatic change. A historical time series from Palma Bay (Balearic Islands, Spain), spanning 45 years and providing clear evidence of warming, was employed to evaluate trends in species abundance and occurrence in relation to their relative climate risk score. While certain high-risk species like Symphodus cinereus and Diplodus annularis showed an increase in abundance over time, others, such as the pipefish Syngnathus acus, Syngnathus typhle and Nerophis maculatus experienced declines. The absence of observed declines in some high-risk species could be attributed to several factors, such as acclimation, adaptation, or unmet response thresholds. However, this does not rule out the potential for future changes in these species. Factors such as increased nutrient influx due to growing human populations and changes in fishing regulations may also have contributed to the observed trends. These findings underscore the intricate interplay of environmental and anthropogenic factors and accentuate the pressing need for sustained, long-term data acquisition to fathom the implications of climate change on this highly important marine ecosystem.


Asunto(s)
Alismatales , Animales , Mar Mediterráneo , Factores de Riesgo , Temperatura , Bahías , Factores de Tiempo
5.
PLoS One ; 19(5): e0302225, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38739607

RESUMEN

Global scallop fisheries are economically important but are associated with environmental impacts to seabed communities resulting from the direct physical contact of the fishing gear with the seabed. Gear modifications attempting to reduce this contact must be economically feasible such that the catch numbers for the target species is maintained or increased. This study investigated the outcome of reducing seabed contact on retained catch of scallops and bycatch by the addition of skids to the bottom of the collecting bag of scallop dredges. We used a paired control experimental design to investigate the impact of the gear modification in different habitat types. The modified skid dredge generally caught more marketable scallops per unit area fished compared with the standard dredge (+5%). However, the skid dredge also retained more bycatch (+11%) and more undersize scallops (+16%). The performance of the two dredges was habitat specific which indicates the importance of adjusting management measures in relation to habitat type. To realize the potential environmental benefits associated with the improvement in catchability of this gear modification, further gear modification is required to reduce the catch of undersize scallops and bycatch. Furthermore we advocate that technical gear innovations in scallop dredging need to be part of a comprehensive and effective fisheries management system.


Asunto(s)
Ecosistema , Explotaciones Pesqueras , Pectinidae , Animales , Conservación de los Recursos Naturales/métodos
6.
Ecol Evol ; 12(6): e9001, 2022 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-35784057

RESUMEN

Biological traits analysis (BTA) links community structure to both ecological functions and response to environmental drivers through species' attributes. In consequence, it has become a popular approach in marine benthic studies. However, BTA will reach a dead end if the scientific community does not acknowledge its current shortcomings and limitations: (a) uncertainties related to data origins and a lack of standardized reporting of trait information; (b) knowledge gaps on the role of multiple interacting traits on driving the organisms' responses to environmental variability; (c) knowledge gaps regarding the mechanistic links between traits and functions; (d) a weak focus on the spatial and temporal variability that is inherent to the trait expression of species; and, last but not least, (e) the large reliance on expert knowledge due to an enormous knowledge gap on the basic ecology of many benthic species. BTA will only reach its full potential if the scientific community is able to standardize and unify the reporting and storage of traits data and reconsider the importance of baseline observational and experimental studies to fill knowledge gaps on the mechanistic links between biological traits, functions, and environmental variability. This challenge could be assisted by embracing new technological advances in marine monitoring, such as underwater camera technology and artificial intelligence, and making use of advanced statistical approaches that consider the interactive nature and spatio-temporal variability of biological systems. The scientific community has to abandon some dead ends and explore new paths that will improve our understanding of individual species, traits, and the functioning of benthic ecosystems.

7.
Ecol Evol ; 12(11): e9472, 2022 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-36340813

RESUMEN

Despite the recent recognition of jellyfish as an important component of marine ecosystems and existing concerns on their potential population increase, they are rarely monitored at the appropriate spatial and temporal scales. Traditional jellyfish monitoring techniques are costly and generally restrict the spatial-temporal resolution limiting the quantity and quality of monitoring data. We introduce Jellytoring 2.0, an automatic recognition tool for jellyfish species based on convolutional neural networks (CNN). We trained Jellytoring 2.0 to identify 15 jellyfish species with a global distribution. Our aim is to offer Jellytoring 2.0 as an open-access tool to serve as the backbone for a system that promotes the creation of large-scale and long-term jellyfish monitoring data. Results reveal that Jellytoring 2.0 performed well in the identification of the 15 species with average precision values ranging between 90% and 99% for most of the species. Four of the species presented slightly lower values (75%-80%). Our system was trained on a relatively small dataset, implying that additional integration of image data will further improve the performance of the CNN. We show how the application of CNNs to image data can deliver a tool that will enable the cost-effective collection of jellyfish data on larger spatial and temporal scales. For Jellytoring 2.0 to become a truly global automatic identification system, we ask scientists and nonscientists to actively contribute with jellyfish image data to extend the number of species it can identify.

8.
Ecol Appl ; 19(3): 761-73, 2009 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-19425437

RESUMEN

Bottom trawling has widespread impacts on benthic communities and habitats. While the direct impacts of trawl disturbances on benthic communities have been extensively studied, the consequences from long-term chronic disturbances are less well understood. The response of benthic macrofauna to chronic otter-trawl disturbance from a Nephrops norvegicus (Norway lobster) fishery was investigated along a gradient of fishing intensity over a muddy fishing ground in the northeastern Irish Sea. Chronic otter trawling had a significant, negative effect on benthic infauna abundance, biomass, and species richness. Benthic epifauna abundance and species richness also showed a significant, negative response, while no such effect was evident for epibenthic biomass. Furthermore, chronic trawl disturbance led to clear changes in community composition of benthic infauna and epifauna. The results presented indicate that otter-trawl impacts are cumulative and can lead to profound changes in benthic communities, which may have far-reaching implications for the integrity of marine food webs. Studies investigating the short-term effects of fishing manipulations previously concluded that otter trawling on muddy substrates had only modest effects on the benthic biota. Hence, the results presented by this study highlight that data from experimental studies can not be readily extrapolated to an ecosystem level and that subtle cumulative effects may only become apparent when fishing disturbances are examined over larger spatial and temporal scales. Furthermore, this study shows that data on chronic effects of bottom trawling on the benthos will be vital in informing the recently advocated move toward an ecosystem approach in fisheries management. As bottom-trawl fisheries are expanding into ever deeper muddy habitats, the results presented here are an important step toward understanding the global ecosystem effects of bottom trawling.


Asunto(s)
Acuicultura , Biodiversidad , Animales , Biomasa , Geografía , Irlanda , Análisis Multivariante , Nephropidae , Océanos y Mares , Dinámica Poblacional , Análisis de Regresión
9.
PeerJ ; 7: e6672, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31065453

RESUMEN

Marine protected areas (MPAs) are increasingly being used as conservation tools in the marine environment. Success of MPAs depends upon sound scientific design and societal support. Studies that have assessed societal preferences for temperate MPAs have generally done it without considering the existence of discrete groups of opinion within society and have largely considered offshore and deep-sea areas. This study quantifies societal preferences and economic support for coastal MPAs in Wales (UK) and assesses the presence of distinct groups of preference for MPA management, through a latent class choice experiment approach. Results show a general support for the protection of the marine environment in the form of MPAs and that society is willing to bear the costs derived from conservation. Despite a general opposition toward MPAs where human activities are completely excluded, there is some indication that three classes of preferences within society can be established regarding the management of potentially sea-floor damaging activities. This type of approach allows for the distinction between those respondents with positive preferences for particular types of management from those who experience disutility. We conclude that insights from these types of analyses can be used by policy-makers to identify those MPA designs and management combinations most likely to be supported by particular sectors of society.

10.
PeerJ ; 7: e6797, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31143530

RESUMEN

The nursery function of coastal habitats is one of the most frequently mentioned and recognized ecosystem services in the valuation of coastal ecosystems. Despite its importance our understanding of the precise habitat parameters and mechanisms that make a habitat important as a nursery area is still limited for many species. The study aimed to establish the importance of different algae morphotypes in providing shelter and food for juvenile coastal fish during the main settlement peaks, in early spring and late summer, in littoral rocky reef systems in the Northwestern Mediterranean. The results of our study showed strong seasonal differences in algae cover, composition and height between the two sampling periods. Overall, during spring the algae were well developed, while in late summer, both density and height, of most algae decreased considerably. Equally, prey biomass, in form of suitable sized invertebrate fauna associated to the algae, decreased. Accordingly, the shelter and food for the fish settling in this habitat during late summer were less abundant, indicating a mismatch between the observed presence of juvenile fish and optimal habitat conditions. Differences in prey densities were detected between algae morphotypes, with structurally more complex algae, such as Cystoseira spp. and Halopteris spp. consistently containing more prey, independent of season, compared to simpler structured morphotypes such as Dictoytales. The study furthermore related juvenile fish density to habitats dominated by different algae morphotypes. Out of the three-study species (Diplodus vulgaris, Symphodus ocellatus, Coris julis) only S. ocellatus showed a significant association with an algae habitat. S. ocellatus related positively to habitats dominated by Dictoytales which provided the highest cover during late summer but had the lowest prey densities. A strong association of this species with Cystoseira, as reported by other studies, could not be confirmed. Cystoseira was abundant within the study area but in a state of dieback, showing loss and reduced height of foliage, typical for the time of year within the study area. It is therefore likely that algae-fish associations are context-dependent and that several algae species may fulfil similar functions. We also discovered that prey biomass did not appear to have an important effect on juvenile abundances. Nevertheless, the availability of prey may influence juvenile fish condition, growth performance and ultimately long-term survival. We therefore suggest that future studies on habitat quality should also include, besides abundance, indicators related to the condition and growth of juveniles.

11.
PLoS One ; 14(1): e0210007, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-30625207

RESUMEN

Coral reefs are threatened by numerous global and local stressors. In the face of predicted large-scale coral degradation over the coming decades, the importance of long-term monitoring of stress-induced ecosystem changes has been widely recognised. In areas where sustained funding is unavailable, citizen science monitoring has the potential to be a powerful alternative to conventional monitoring programmes. In this study we used data collected by volunteers in Southeast Sulawesi (Indonesia), to demonstrate the potential of marine citizen science programmes to provide scientifically sound information necessary for detecting ecosystem changes in areas where no alternative data are available. Data were collected annually between 2002 and 2012 and consisted of percent benthic biotic and abiotic cover and fish counts. Analyses revealed long-term coral reef ecosystem change. We observed a continuous decline of hard coral, which in turn had a significant effect on the associated fishes, at community, family and species levels. We provide evidence of the importance of marine citizen science programmes in detecting long-term ecosystem change as an effective way of delivering conservation data to local government and national agencies. This is particularly true for areas where funding for monitoring is unavailable, resulting in an absence of ecological data. For citizen science data to contribute to ecological monitoring and local decision-making, the data collection protocols need to adhere to sound scientific standards, and protocols for data evaluation need to be available to local stakeholders. Here, we describe the monitoring design, data treatment and statistical analyses to be used as potential guidelines in future marine citizen science projects.


Asunto(s)
Ecosistema , Animales , Conservación de los Recursos Naturales , Arrecifes de Coral , Geografía , Indonesia , Biología Marina
12.
PeerJ ; 6: e4707, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29785340

RESUMEN

In the Balearic Islands, different trammel net designs have been adopted to promote fisheries sustainability and reduce discards. Here, we compare the catch performance of three trammel net designs targeting the spiny lobster Palinurus elephas in terms of biomass, species composition and revenue from commercial catches and discards. Designs differ in the netting fiber type (standard polyfilament, PMF, or a new polyethylene multi-monofilament, MMF) and the use of a guarding net or greca, a mesh piece intended to reduce discards. Catches were surveyed by an on-board observer from 1,550 netting walls corresponding to 70 nets. The number of marketable species captured indicated that the lobster trammel net fishery has multiple targets, which contribute significantly to the total revenue. The discarded species ranged from habitat-forming species to elasmobranches, but the magnitude of gear-habitat interactions on the long term dynamics of benthos remains unclear. No relevant differences in revenue and weight of discards were detected after Bayesian analyses. However, the species composition of discards was different when using greca. Interestingly, high immediate survival was found for discarded undersized lobsters, while a seven day survival assessment, using captive observation, gave an asymptotic estimate of survival probability as 0.64 (95% CI [0.54-0.76]). Therefore, it is recommended that it would be beneficial for this stock if an exemption from the EU landing obligation regulation was sought for undersized lobsters in the Balearic trammel net fishery.

13.
Sci Rep ; 7(1): 6334, 2017 07 24.
Artículo en Inglés | MEDLINE | ID: mdl-28740093

RESUMEN

Bottom trawling can change food availability for benthivorous demersal species by (i) changing benthic prey composition through physical seabed impacts and (ii) by removing overall benthic consumer biomass increasing the net availability of benthic prey for remaining individuals. Thus trawling may both negatively and positively influence the quantity and quality of food available. Using δ 13C and δ 15N we investigated potential diet changes of three commercially exploited species across trawling gradients in the Kattegat (plaice, dab and Norway lobster (Nephrops)) and the Irish Sea (Nephrops). In the Kattegat, trawling affected primarily the biomass of benthic consumers, lowering competition. Nephrops showed significant positive relationships for δ 13C and a domed relationship for δ 15N with trawling. In the Irish Sea, intense trawling had a negative effect on benthic prey. δ 13C and δ 15N thus showed the inverse relationships to those observed in the Kattegat. Plaice from the Kattegat, showed a significant relationship with trawling intensity for δ 13C, but not for δ 15N. No relationship was found for dab. Changes of δ 13C and δ 15N correlated with changes in condition of species. The results show that the removal of demersal competitors and benthos by trawling can change the diets of commercial species, ultimately affecting their body condition.


Asunto(s)
Alimentación Animal/análisis , Isótopos de Carbono/análisis , Peces/fisiología , Isótopos de Nitrógeno/análisis , Animales , Comercio , Conducta Alimentaria , Explotaciones Pesqueras , Océanos y Mares , Dinámica Poblacional
14.
Mar Environ Res ; 125: 34-41, 2017 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-28103523

RESUMEN

Human pressure on coastal areas is affecting essential ecosystems including fish nursery habitats. Among these anthropogenic uses, the seasonal increment in the pressure due to leisure activities such as coastal tourism and yachting is an important environmental stressor in many coastal zones. These pressures may elicit understudied impacts due to, for example, sunscreens or other seasonal pollutants. The island of Majorca, northwest Mediterranean Sea, experiences one of the highest number of tourist visits per capita in the world, thus the surrounding coastal habitat is subject to high anthropogenic seasonal stress. Studies on early stages of fishes have observed responses to coastal chemical cues for the selection or avoidance of habitats. However, the potential interferences of human impacts on these signals are largely unknown. A choice chamber was used to determine water type preference and behaviour in naïve settled juvenile gilt-head sea bream (Sparus aurata), a temperate species of commercial interest. Fish were tested individually for behavioural changes with respect to water types from potential beneficial habitats, such as seawater with extract of the endemic seagrass Posidonia oceanica, anthropogenically influenced habitats such as water extracted from a commercial and recreational harbour and seawater mixed with sunscreen at concentrations observed in coastal waters. Using a Bayesian approach, we investigated a) water type preference; b) mean speed; and c) variance in the movement (as an indicator of burst swimming activity, or "sprint" behaviour) as behavioural descriptors with respect to water type. Fish spent similar percentage of time in treatment and control water types. However, movement descriptors showed that fish in sunscreen water moved slower (98.43% probability of being slower) and performed fewer sprints (90.1% probability of having less burst in speed) compared to control water. Less evident increases in sprints were observed in harbour water (73.56% more sprints), and seagrass (79.03% more) in comparison to control water. When seagrass water was tested against harbour water, the latter elicited a higher number of sprints (91.66% increase). We show that juvenile gilt-head seabream are able to react to a selection of naturally occurring chemically different odourscapes, including the increasingly important presence of sunscreen products, and provide a plausible interpretation of the observed behavioural patterns.


Asunto(s)
Conducta Animal/efectos de los fármacos , Monitoreo del Ambiente , Peces/fisiología , Natación/fisiología , Contaminantes Químicos del Agua/toxicidad , Animales , Teorema de Bayes , España
15.
Mar Environ Res ; 92: 144-53, 2013 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-24138797

RESUMEN

Understanding variability in reproductive schedules is essential to the management of recruitment limited fisheries such as that of Pecten maximus. Small scale (<5 km) variation in gonad condition and the onset of spawning of P. maximus were found among commercial scallop grounds in Isle of Man waters. Environmental and fishing drivers of these spatial patterns were investigated using a generalised additive model. Rate of change in temperature over the month prior to sampling was identified as the short term driver of gonad weight associated with the autumn spawning event. Long term drivers were average annual chlorophyll a concentration, scallop density, stratification index and shell size. The model explained 42.8% of deviance in gonad weight. Within site variation in gonad condition was high, indicating a "bet hedging" reproductive strategy which may decrease the chance of fertilisation especially at low densities. Therefore, areas protected from fishing, where scallop densities can increase may help buffer against reproductive failure. An increase in shell length from 100 mm to 110 mm equated to an increase of approximately 20% in gonad weight. Protecting scallops from fishing mortality until 110 mm (age four) compared to 100 mm (age three) may lead to an overall increase in lifetime reproductive output by a factor of 3.4.


Asunto(s)
Ecosistema , Pecten/fisiología , Reproducción , Exoesqueleto/anatomía & histología , Animales , Clorofila/metabolismo , Clorofila A , Femenino , Explotaciones Pesqueras , Gónadas/anatomía & histología , Masculino , Modelos Biológicos , Densidad de Población , Temperatura , Reino Unido
16.
Mar Environ Res ; 73: 85-95, 2012 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-22119657

RESUMEN

The negative impact of demersal fishing gears on the marine environment may be mitigated by utilizing less damaging fishing gears. Within this context three queen scallop fishing gears were tested for their catch efficiencies and their environmental impact on benthos: a traditional 'Newhaven' dredge, a new dredge design with a rubber lip instead of the traditional teeth as its main new design feature and an otter trawl. Both, the new dredge and the otter trawl showed high catches and relatively low by-catches. Catches made with the traditional dredge were lower and contained larger amounts of non-target species. Both dredges primarily caught invertebrate species, while by-catches of the otter trawl were dominated by demersal fish. The impact of these gears on the benthic biota demonstrated that while no effects were detected for the otter trawl both dredges showed similar negative effects. Clear negative effects were evident for the brittlestar Ophiura ophiura while positive trends for the common starfish Asterias rubens and the hermit crab Pagurus bernhardus indicated scavenging effects. Due to its higher catch efficiency the new dredge caused less damage per unit catch compared to the traditional dredge, yet compared to the otter trawl it appears less environmentally friendly. However, the new dredge may be an alternative to the otter trawls for fisheries where the by-catch of demersal fish has been identified as a significant problem.


Asunto(s)
Acuicultura/instrumentación , Pectinidae/fisiología , Animales , Acuicultura/normas , Ambiente , Peces/fisiología , Invertebrados/fisiología , Reino Unido
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