Hilmar Hinz - Academia.edu (original) (raw)
Papers by Hilmar Hinz
Limnology and Oceanography Bulletin
ASLO and the local and scientific committees continue working on the forthcoming aquatic sciences... more ASLO and the local and scientific committees continue working on the forthcoming aquatic sciences meeting in Palma. Given the uncertainty that the current COVID-19 pandemic situation poses for travelling and social-distancing measures, we are currently planning for a hybrid meeting, i.e., combining an in-person meeting with online participation. We are aiming to provide a physical venue for limnologists and oceanographers from around the world to meet, discuss and share their science, however this year there will be added online components and possibilities. Rescheduling of the ASLO meeting to early summer offers participants the potential to complement their scientific discussion during the meeting with plenty of social and outdoor activities.
Marine Biology
The nursery function of littoral habitats for juvenile fish is widely recognized, but data on the... more The nursery function of littoral habitats for juvenile fish is widely recognized, but data on the specific habitat features that contribute to this function is sparse for many species, in part related to the difficulty of studying juvenile fish in their natural environment. However, this information is required to understand the potential risks of environmental change to the nursery functions of habitats. In this context, the habitat choice behaviour, with respect to differences in structural features, was evaluated for three Mediterranean littoral fish species known to be associated to macrophytes as juveniles. The overarching aim of this experiment was to determine if juveniles actively choose between different macrophyte configurations of varying complexity and height. Juveniles were exposed simultaneously to multiple visual habitat stimuli within an experimental choice arena, and their swimming behaviour was tracked by video recordings to determine the amount of time they spent ...
Biodiversity and Conservation
The diversity of benthic communities on continental shelves is tightly linked to the diversity of... more The diversity of benthic communities on continental shelves is tightly linked to the diversity of habitats. Therefore, considering seascape habitat composition can help to gain insights into the spatial variability of benthic communities and move away from single-habitats approaches. This perspective needs different analytical methods, such as network analysis that enable the study of complex ecological interactions. This work explores the relationships between habitat and benthic species diversity in the Menorca Channel (the Balearic Islands, western Mediterranean). The seascape in the study area is a mosaic of alternating biogenic and sandy habitats that increases the total benthic species richness. Of the 442 benthic species included in the analyses, 286 species are shared by the six habitats identified, contributing to ecological connectivity across the seascape; 73 generalist species inhabit all six habitats simultaneously, however, 156 species are specialists and are linked to...
Ecology and Evolution
Despite the recent recognition of jellyfish as an important component of marine ecosystems and ex... more 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 slight...
1. The use of reserves as conservation tools is widespread. However, evaluating the effectiveness... more 1. The use of reserves as conservation tools is widespread. However, evaluating the effectiveness of reserve implementation for long-lived species has been problematic as it requires sampling programmes over long time scales that are appropriate to species’ longevity and recovery rates. In the sea, towed bottom fishing gears alter the biodiversity and ecosystem services provided by benthic communities and habitats. Marine reserves have been used to manage these impacts but our understanding of the drivers of their effectiveness for the conservation of temperate reefs is incomplete. 2. We examined the effectiveness of marine reserves for recovery of temperate reef fauna in relation to their life history. We used an underwater video to sample six species with different life histories across 60 sites that varied in the duration of protection from towed mobile fishing gear at 0, 1, 8 and 10 years. 3. Species with a high dispersal potential and less habitat specific requirements such as soft corals and king scallops recovered to close to their carrying capacity in <3 years. In contrast, the longer-lived Ross coral and pink seafans increased in abundance but had not fully recovered; with their projected recovery time being 17 to 20 years. 4. Ongoing recovery was evident for long-lived species as their mean body -size increased significantly across all treatments, whereas shorter-lived species such as queen scallops did not change in size and were assumed to have fully recovered. 5. This study shows that the recovery rates of biota depend on life history factors, such as larval longevity and dispersal potential. Recovery for species that had low dispersal potential and specific habitat requirements was slow and could take >20 years. This suggests activities such as bottom trawling or dredging should be avoided where such species occur if their conservation is an objective. In contrast, species with high dispersal potential and less habitat specific requirements had shorter recovery timescales of ~2-3 years and would be more amenable to managed trawl frequencies in areas where activities such as fishing occur
The length and weight for individual fish that was used to estimate the condition of the fish. Th... more The length and weight for individual fish that was used to estimate the condition of the fish. The length (to the nearest mm) and weight (to the nearest g) of the individual fish in the catch was recorded. If the catch of a species in a haul was large (>50 individuals), a subsample of ≥50 fish was measured and weighed. The BMI (body mass index) column is given here for quality assurance purposes only and not used in the analyses. Some values outside the possible range and have been marked as such
Stomach content data for plaice and dab have been submitted to the fish stomach database DAPSTOM ... more Stomach content data for plaice and dab have been submitted to the fish stomach database DAPSTOM that is maintained by CEFAS, UK. This contains the species, length, and weight of each fish, and the identity, number and weight of each prey item. The digestion state of each prey item is also given
The data presented in the publication from the Kattegat, except for the isotope (see above), data... more The data presented in the publication from the Kattegat, except for the isotope (see above), data can be found in Dyrad associated to an earlier publications by the authors: Data from: Bottom trawling affects fish condition through changes in the ratio of prey availability to density of competitors Hiddink JG, Moranta J, Balestrini S, Sciberras M, Cendrier M, Bowyer R, Kaiser MJ, Sköld M, Jonsson P, Bastardie F, Hinz H Date Published: May 31, 2016 DOI: http://dx.doi.org/10.5061/dryad.04dv4 To access the Kattegat data please use the following link http://datadryad.org/resource/doi:10.5061/dryad.04dv
Latitude and longitude of the station sampled in the Irish Se
Deep Learning: Algorithms and Applications, 2019
Ecological studies are increasingly using video image data to study the distribution and behaviou... more Ecological studies are increasingly using video image data to study the distribution and behaviour of organisms. Particularly in marine sciences cameras are utilised to access underwater environments. Up till now image data has been processed by human observers which is costly and often represents repetitive mundane work. Deep learning techniques that can automatically classify objects can increase the speed and the amounts of data that can be processed. This ultimately will make image processing in ecological studies more cost effective, allowing studies to invest in larger, more robust sampling designs. As such, deep learning will be a game changer for ecological research helping to improve the quality and quantity of the data that can be collected. Within this chapter we introduce two case studies to demonstrate the application of deep learning techniques in marine ecological studies. The first example demonstrates the use of deep learning in the detection and classification of a...
Conservation Biology, 2021
The unlimited economic growth that fuels capitalism's metabolism has profoundly transformed a... more 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 scien...
Marine Ecology Progress Series, 2019
Two fish species from the temperate reef community studied, East Atlantic peacock wrasse Symphodu... more Two fish species from the temperate reef community studied, East Atlantic peacock wrasse Symphodus tinca (foreground) and common two-banded seabream Diplodus vulgaris (background).
Journal of Applied Ecology, 2018
1. The use of reserves as conservation tools is widespread. However, evaluating the effectiveness... more 1. The use of reserves as conservation tools is widespread. However, evaluating the effectiveness of reserve implementation for long-lived species has been problematic as it requires sampling regimes on the long timescales that are appropriate to species' longevity and recovery rates. In the sea, towed bottom-fishing gears alter the biodiversity and ecosystem services provided by benthic communities and habitats. Marine reserves have been used to manage these impacts but our understanding of the drivers of their effectiveness for the conservation of temperate reefs is incomplete. 2. We examined the effectiveness of marine reserves for recovery of temperate reef fauna in relation to their life-history. We used an underwater video to sample six species with different life histories across 60 sites that varied in the duration of protection from towed mobile fishing gear at 0, 1, 8 and 10 years. 3. Species with a high dispersal potential and less habitat specific requirements such as soft corals and king scallops recovered to close to their carrying capacity in <3 years. In contrast, the longer-lived Ross coral and pink seafans increased in abundance but had not fully recovered and their projected recovery time was 17 to 20 years. 4. Ongoing recovery was evident for long-lived species as their mean body-size increased significantly across all treatments, whereas shorter-lived species such as queen scallops did not change in size and were assumed to have fully recovered. Applications and synthesis: The present study shows that the recovery rates of biota depend on their life-history, such as larval longevity and dispersal potential. Recovery for species that had low dispersal potential and specific habitat requirements was slow and could take >20 years. This suggests that activities such as bottom-trawling or dredging should be avoided where such species occur if their conservation is an objective. In contrast, species with high dispersal potential and less habitat specific requirements had shorter recovery timescales of ~2-3 years and would be more amenable to managed trawl frequencies in areas where activities such as fishing occur.
PeerJ, 2019
Marine protected areas (MPAs) are increasingly being used as conservation tools in the marine env... more 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...
PeerJ, 2018
In the Balearic Islands, different trammel net designs have been adopted to promote fisheries sus... more 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 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 , 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 o...
Marine Biology, 2017
distributions, including the smallest juvenile fraction. The capacity of the SBRUV system increas... more distributions, including the smallest juvenile fraction. The capacity of the SBRUV system increased the synopticity with respect to typical surveys. We tested the system over seagrass meadows of Posidonia oceanica in a Mediterranean bay, investigating the relationship of juvenile abundance and size of the sparid Diplodus annularis with depth, time of day and protection status (i.e. inside and outside of a Marine Protected Area, MPA). We found significant effects of the depth on the length of the older size classes fraction (larger sizes at deeper stations) and an effect of time of the day on the abundance (less abundant during the evenings), and an opposite pattern was observed for early juvenile's abundances. The MPA protection had no effect in D. annularis population structure. Interestingly, the relative abundance of D. annularis early juveniles was comparable at all depths, from 2 to 20 m, which suggests a potentially higher nursery value of P. oceanica meadows than earlier thought.
Journal of Experimental Marine Biology and Ecology, 2017
In order to recruit into adult populations juvenile fish must be able to find food, successfully ... more In order to recruit into adult populations juvenile fish must be able to find food, successfully compete with other organisms and avoid predation within a habitat, in other words they must be able to locate favourable and avoid detrimental conditions. Bio-chemical research into fish detection and discrimination between chemical cues is extensive, however whether olfactory mechanisms are critical in habitat selection and avoidance of detrimental conditions within the marine environment remains under-researched. Despite being one of the scientifically most explored seas, studies on the use of olfactory system in the selection of water masses of the Mediterranean fish species are absent. Using a chemical choice flume, the chemically mediated behaviour choices to distinct chemical cues (algae, seagrass, predator and conspecifics) of Symphodus ocellatus, a common Mediterranean fish, were investigated. In addition to the conventional analysis, which relies on the amount of the time spent in the specific water mass as the main indicator of preference, the behavioural response triggered by the detection of a particular cue was also examined, by analysing the mean and variance of speed of the individual fish movements, a complimentary approach previously not considered in the flume experiments. Bayesian statistical method was used to calculate both, proportion of time spent in the specific water mass, as well as to analyse the behavioural response of each individual within the specific water mass. In terms of the time spent, the flume trials conducted resulted in no significant fish selection preference or avoidance for any of the water masses tested, however varied speeds and number of burst speed movements were observed in a number of trials. When no olfactory stimulus was present, no change in behaviour was triggered. Thus, juvenile S. ocellatus undoubtedly has a capacity of change in behaviour to a complex array of olfactory stimuli, nevertheless the response in the flume experiment was more complex than just the differences in time of the occupancy between the water masses. As a result, the analyses of speed could in future prove to be an important complementary tool for studying behavioural responses of fish using this methodology. The findings are coupled with the development of the rigorous novel protocol for behavioural analyses using exclusively publicly available apparatus and software, all described within the manuscript.
Journal of Applied Ecology, 2016
1. Bottom-trawl fisheries are widespread and cause mortality of benthic invertebrates, which in t... more 1. Bottom-trawl fisheries are widespread and cause mortality of benthic invertebrates, which in turn may lead to a decrease in the availability of prey for target fish species. Exploitation also reduces the abundance of the fish species themselves. Modelling studies have shown that bottom trawling could lead to both increases and decreases in fish production, but so far empirical evidence to test these ideas has been very limited. We hypothesize that the effect of bottom trawling on the food intake and condition of fish depends on how the ratio of prey to consumers changes with increasing fishing pressure. 2. We assessed the impact of bottom trawling on the food availability, condition and stomach contents of three flatfishes and Norway lobster in an area in the Kattegat that is characterized by a steep commercial bottom-trawling gradient due to the establishment of an area closed to all fisheries, but otherwise homogeneous environmental conditions. 3. For plaice, prey biomass initially decreased slower with trawling than the biomass of fish, and as a result the amount of food available per plaice increased before decreasing at trawling frequencies >5 times y-1. This pattern was mirrored in both the condition and stomach contents of plaice, and for Longrough dab. 4. No effect of trawling on dab prey and condition was found. Conversely, the condition of the main target species Norway lobster increased as its biomass decreased with increased trawling intensities. 5. Together these results support the idea that when the abundance of the prey declines in response to exploitation, the ratio of the prey to consumer biomass will determine whether exploitation will result in an increase or a decrease of the food intake and condition of the predator. Synthesis and application. Our study indicates that fish production may be maximized by keeping trawling intensities relatively low, although this may negatively affect the economically more important Nephrops fishery. The effects of bottom trawls may be mitigated by switching to gears that affect prey availability to a lesser extent, such pots/creels.
Limnology and Oceanography Bulletin
ASLO and the local and scientific committees continue working on the forthcoming aquatic sciences... more ASLO and the local and scientific committees continue working on the forthcoming aquatic sciences meeting in Palma. Given the uncertainty that the current COVID-19 pandemic situation poses for travelling and social-distancing measures, we are currently planning for a hybrid meeting, i.e., combining an in-person meeting with online participation. We are aiming to provide a physical venue for limnologists and oceanographers from around the world to meet, discuss and share their science, however this year there will be added online components and possibilities. Rescheduling of the ASLO meeting to early summer offers participants the potential to complement their scientific discussion during the meeting with plenty of social and outdoor activities.
Marine Biology
The nursery function of littoral habitats for juvenile fish is widely recognized, but data on the... more The nursery function of littoral habitats for juvenile fish is widely recognized, but data on the specific habitat features that contribute to this function is sparse for many species, in part related to the difficulty of studying juvenile fish in their natural environment. However, this information is required to understand the potential risks of environmental change to the nursery functions of habitats. In this context, the habitat choice behaviour, with respect to differences in structural features, was evaluated for three Mediterranean littoral fish species known to be associated to macrophytes as juveniles. The overarching aim of this experiment was to determine if juveniles actively choose between different macrophyte configurations of varying complexity and height. Juveniles were exposed simultaneously to multiple visual habitat stimuli within an experimental choice arena, and their swimming behaviour was tracked by video recordings to determine the amount of time they spent ...
Biodiversity and Conservation
The diversity of benthic communities on continental shelves is tightly linked to the diversity of... more The diversity of benthic communities on continental shelves is tightly linked to the diversity of habitats. Therefore, considering seascape habitat composition can help to gain insights into the spatial variability of benthic communities and move away from single-habitats approaches. This perspective needs different analytical methods, such as network analysis that enable the study of complex ecological interactions. This work explores the relationships between habitat and benthic species diversity in the Menorca Channel (the Balearic Islands, western Mediterranean). The seascape in the study area is a mosaic of alternating biogenic and sandy habitats that increases the total benthic species richness. Of the 442 benthic species included in the analyses, 286 species are shared by the six habitats identified, contributing to ecological connectivity across the seascape; 73 generalist species inhabit all six habitats simultaneously, however, 156 species are specialists and are linked to...
Ecology and Evolution
Despite the recent recognition of jellyfish as an important component of marine ecosystems and ex... more 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 slight...
1. The use of reserves as conservation tools is widespread. However, evaluating the effectiveness... more 1. The use of reserves as conservation tools is widespread. However, evaluating the effectiveness of reserve implementation for long-lived species has been problematic as it requires sampling programmes over long time scales that are appropriate to species’ longevity and recovery rates. In the sea, towed bottom fishing gears alter the biodiversity and ecosystem services provided by benthic communities and habitats. Marine reserves have been used to manage these impacts but our understanding of the drivers of their effectiveness for the conservation of temperate reefs is incomplete. 2. We examined the effectiveness of marine reserves for recovery of temperate reef fauna in relation to their life history. We used an underwater video to sample six species with different life histories across 60 sites that varied in the duration of protection from towed mobile fishing gear at 0, 1, 8 and 10 years. 3. Species with a high dispersal potential and less habitat specific requirements such as soft corals and king scallops recovered to close to their carrying capacity in <3 years. In contrast, the longer-lived Ross coral and pink seafans increased in abundance but had not fully recovered; with their projected recovery time being 17 to 20 years. 4. Ongoing recovery was evident for long-lived species as their mean body -size increased significantly across all treatments, whereas shorter-lived species such as queen scallops did not change in size and were assumed to have fully recovered. 5. This study shows that the recovery rates of biota depend on life history factors, such as larval longevity and dispersal potential. Recovery for species that had low dispersal potential and specific habitat requirements was slow and could take >20 years. This suggests activities such as bottom trawling or dredging should be avoided where such species occur if their conservation is an objective. In contrast, species with high dispersal potential and less habitat specific requirements had shorter recovery timescales of ~2-3 years and would be more amenable to managed trawl frequencies in areas where activities such as fishing occur
The length and weight for individual fish that was used to estimate the condition of the fish. Th... more The length and weight for individual fish that was used to estimate the condition of the fish. The length (to the nearest mm) and weight (to the nearest g) of the individual fish in the catch was recorded. If the catch of a species in a haul was large (>50 individuals), a subsample of ≥50 fish was measured and weighed. The BMI (body mass index) column is given here for quality assurance purposes only and not used in the analyses. Some values outside the possible range and have been marked as such
Stomach content data for plaice and dab have been submitted to the fish stomach database DAPSTOM ... more Stomach content data for plaice and dab have been submitted to the fish stomach database DAPSTOM that is maintained by CEFAS, UK. This contains the species, length, and weight of each fish, and the identity, number and weight of each prey item. The digestion state of each prey item is also given
The data presented in the publication from the Kattegat, except for the isotope (see above), data... more The data presented in the publication from the Kattegat, except for the isotope (see above), data can be found in Dyrad associated to an earlier publications by the authors: Data from: Bottom trawling affects fish condition through changes in the ratio of prey availability to density of competitors Hiddink JG, Moranta J, Balestrini S, Sciberras M, Cendrier M, Bowyer R, Kaiser MJ, Sköld M, Jonsson P, Bastardie F, Hinz H Date Published: May 31, 2016 DOI: http://dx.doi.org/10.5061/dryad.04dv4 To access the Kattegat data please use the following link http://datadryad.org/resource/doi:10.5061/dryad.04dv
Latitude and longitude of the station sampled in the Irish Se
Deep Learning: Algorithms and Applications, 2019
Ecological studies are increasingly using video image data to study the distribution and behaviou... more Ecological studies are increasingly using video image data to study the distribution and behaviour of organisms. Particularly in marine sciences cameras are utilised to access underwater environments. Up till now image data has been processed by human observers which is costly and often represents repetitive mundane work. Deep learning techniques that can automatically classify objects can increase the speed and the amounts of data that can be processed. This ultimately will make image processing in ecological studies more cost effective, allowing studies to invest in larger, more robust sampling designs. As such, deep learning will be a game changer for ecological research helping to improve the quality and quantity of the data that can be collected. Within this chapter we introduce two case studies to demonstrate the application of deep learning techniques in marine ecological studies. The first example demonstrates the use of deep learning in the detection and classification of a...
Conservation Biology, 2021
The unlimited economic growth that fuels capitalism's metabolism has profoundly transformed a... more 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 scien...
Marine Ecology Progress Series, 2019
Two fish species from the temperate reef community studied, East Atlantic peacock wrasse Symphodu... more Two fish species from the temperate reef community studied, East Atlantic peacock wrasse Symphodus tinca (foreground) and common two-banded seabream Diplodus vulgaris (background).
Journal of Applied Ecology, 2018
1. The use of reserves as conservation tools is widespread. However, evaluating the effectiveness... more 1. The use of reserves as conservation tools is widespread. However, evaluating the effectiveness of reserve implementation for long-lived species has been problematic as it requires sampling regimes on the long timescales that are appropriate to species' longevity and recovery rates. In the sea, towed bottom-fishing gears alter the biodiversity and ecosystem services provided by benthic communities and habitats. Marine reserves have been used to manage these impacts but our understanding of the drivers of their effectiveness for the conservation of temperate reefs is incomplete. 2. We examined the effectiveness of marine reserves for recovery of temperate reef fauna in relation to their life-history. We used an underwater video to sample six species with different life histories across 60 sites that varied in the duration of protection from towed mobile fishing gear at 0, 1, 8 and 10 years. 3. Species with a high dispersal potential and less habitat specific requirements such as soft corals and king scallops recovered to close to their carrying capacity in <3 years. In contrast, the longer-lived Ross coral and pink seafans increased in abundance but had not fully recovered and their projected recovery time was 17 to 20 years. 4. Ongoing recovery was evident for long-lived species as their mean body-size increased significantly across all treatments, whereas shorter-lived species such as queen scallops did not change in size and were assumed to have fully recovered. Applications and synthesis: The present study shows that the recovery rates of biota depend on their life-history, such as larval longevity and dispersal potential. Recovery for species that had low dispersal potential and specific habitat requirements was slow and could take >20 years. This suggests that activities such as bottom-trawling or dredging should be avoided where such species occur if their conservation is an objective. In contrast, species with high dispersal potential and less habitat specific requirements had shorter recovery timescales of ~2-3 years and would be more amenable to managed trawl frequencies in areas where activities such as fishing occur.
PeerJ, 2019
Marine protected areas (MPAs) are increasingly being used as conservation tools in the marine env... more 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...
PeerJ, 2018
In the Balearic Islands, different trammel net designs have been adopted to promote fisheries sus... more 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 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 , 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 o...
Marine Biology, 2017
distributions, including the smallest juvenile fraction. The capacity of the SBRUV system increas... more distributions, including the smallest juvenile fraction. The capacity of the SBRUV system increased the synopticity with respect to typical surveys. We tested the system over seagrass meadows of Posidonia oceanica in a Mediterranean bay, investigating the relationship of juvenile abundance and size of the sparid Diplodus annularis with depth, time of day and protection status (i.e. inside and outside of a Marine Protected Area, MPA). We found significant effects of the depth on the length of the older size classes fraction (larger sizes at deeper stations) and an effect of time of the day on the abundance (less abundant during the evenings), and an opposite pattern was observed for early juvenile's abundances. The MPA protection had no effect in D. annularis population structure. Interestingly, the relative abundance of D. annularis early juveniles was comparable at all depths, from 2 to 20 m, which suggests a potentially higher nursery value of P. oceanica meadows than earlier thought.
Journal of Experimental Marine Biology and Ecology, 2017
In order to recruit into adult populations juvenile fish must be able to find food, successfully ... more In order to recruit into adult populations juvenile fish must be able to find food, successfully compete with other organisms and avoid predation within a habitat, in other words they must be able to locate favourable and avoid detrimental conditions. Bio-chemical research into fish detection and discrimination between chemical cues is extensive, however whether olfactory mechanisms are critical in habitat selection and avoidance of detrimental conditions within the marine environment remains under-researched. Despite being one of the scientifically most explored seas, studies on the use of olfactory system in the selection of water masses of the Mediterranean fish species are absent. Using a chemical choice flume, the chemically mediated behaviour choices to distinct chemical cues (algae, seagrass, predator and conspecifics) of Symphodus ocellatus, a common Mediterranean fish, were investigated. In addition to the conventional analysis, which relies on the amount of the time spent in the specific water mass as the main indicator of preference, the behavioural response triggered by the detection of a particular cue was also examined, by analysing the mean and variance of speed of the individual fish movements, a complimentary approach previously not considered in the flume experiments. Bayesian statistical method was used to calculate both, proportion of time spent in the specific water mass, as well as to analyse the behavioural response of each individual within the specific water mass. In terms of the time spent, the flume trials conducted resulted in no significant fish selection preference or avoidance for any of the water masses tested, however varied speeds and number of burst speed movements were observed in a number of trials. When no olfactory stimulus was present, no change in behaviour was triggered. Thus, juvenile S. ocellatus undoubtedly has a capacity of change in behaviour to a complex array of olfactory stimuli, nevertheless the response in the flume experiment was more complex than just the differences in time of the occupancy between the water masses. As a result, the analyses of speed could in future prove to be an important complementary tool for studying behavioural responses of fish using this methodology. The findings are coupled with the development of the rigorous novel protocol for behavioural analyses using exclusively publicly available apparatus and software, all described within the manuscript.
Journal of Applied Ecology, 2016
1. Bottom-trawl fisheries are widespread and cause mortality of benthic invertebrates, which in t... more 1. Bottom-trawl fisheries are widespread and cause mortality of benthic invertebrates, which in turn may lead to a decrease in the availability of prey for target fish species. Exploitation also reduces the abundance of the fish species themselves. Modelling studies have shown that bottom trawling could lead to both increases and decreases in fish production, but so far empirical evidence to test these ideas has been very limited. We hypothesize that the effect of bottom trawling on the food intake and condition of fish depends on how the ratio of prey to consumers changes with increasing fishing pressure. 2. We assessed the impact of bottom trawling on the food availability, condition and stomach contents of three flatfishes and Norway lobster in an area in the Kattegat that is characterized by a steep commercial bottom-trawling gradient due to the establishment of an area closed to all fisheries, but otherwise homogeneous environmental conditions. 3. For plaice, prey biomass initially decreased slower with trawling than the biomass of fish, and as a result the amount of food available per plaice increased before decreasing at trawling frequencies >5 times y-1. This pattern was mirrored in both the condition and stomach contents of plaice, and for Longrough dab. 4. No effect of trawling on dab prey and condition was found. Conversely, the condition of the main target species Norway lobster increased as its biomass decreased with increased trawling intensities. 5. Together these results support the idea that when the abundance of the prey declines in response to exploitation, the ratio of the prey to consumer biomass will determine whether exploitation will result in an increase or a decrease of the food intake and condition of the predator. Synthesis and application. Our study indicates that fish production may be maximized by keeping trawling intensities relatively low, although this may negatively affect the economically more important Nephrops fishery. The effects of bottom trawls may be mitigated by switching to gears that affect prey availability to a lesser extent, such pots/creels.