Jan Seys - Academia.edu (original) (raw)

Papers by Jan Seys

There is a growing cause for concern on envenoming European species because of jellyfish blooms, ... more There is a growing cause for concern on envenoming European species because of jellyfish blooms, climate change and globalization displacing species. Treatment of envenomation involves the prevention of further nematocyst release and relieving local and systemic symptoms. Many anecdotal treatments are available but species-specific first aid response is essential for effective treatment. However, species identification is difficult in most cases. There is evidence that oral analgesics, seawater, baking soda slurry and 42–45 ˝ C hot water are effective against nematocyst inhibition and giving pain relief. The application of topical vinegar for 30 s is effective on stings of specific species. Treatments, which produce osmotic or pressure changes can exacerbate the initial sting and aggravate symptoms, common among many anecdotal treatments. Most available therapies are based on weak evidence and thus it is strongly recommended that randomized clinical trials are undertaken. We recommend a vital increase in directed research on the effect of environmental factors on envenoming mechanisms and to establish a species-specific treatment. Adequate signage on jellyfish stings and standardized first aid protocols with emphasis on protective equipment and avoidance of jellyfish to minimize cases should be implemented in areas at risk.

Trends in oil pollution in the southernmost (Belgian) part of the North Sea were analysed using a... more Trends in oil pollution in the southernmost (Belgian) part of the North Sea were analysed using a dataset of 37 years (1962-99) of annual national beached bird surveys conducted in February each year. The most abundant seabird groups represented in the beached birds were auks (31%), gulls (28%), scoters (17%) and Kittiwake (9%). Oil rates of most bird species/taxa indicate

Heb je je wel eens afgevraagd waarom de zandbank 'Trapegeer' zo heet, of hoe de 'kabeljauw' aan z... more Heb je je wel eens afgevraagd waarom de zandbank 'Trapegeer' zo heet, of hoe de 'kabeljauw' aan zijn naam gekomen is? Of ben je veeleer benieuwd naar de persoon achter de 'Thorntonbank' of naar de ontstaansgeschiedenis van de maritieme term 'kraaienest'? Geen nood, wij zochten de betekenis van de meest intrigerende zeewoorden voor je op en presenteren hieruit per editie van De Grote Rede twee termen: telkens één naam van een zandbank of geul op zee, en één niet-toponiem. Met de hulp van een experten-team waagt De Grote Rede zich op het gladde ijs van de historische en etymologische woordverklaring en laat je meegenieten van de 'best professional judgment' van deze zeewoordenaars.

Aquatic Oligochaetes, 1999

The benthic fauna of the Belgian part of the polluted Schelde estuary, called the Zeeschelde, was... more The benthic fauna of the Belgian part of the polluted Schelde estuary, called the Zeeschelde, was studied in September-October 1996 at 143 stations along 35 transects. This study is part of the OMES research program, funded by the Flemish Government, to build an ecosystem model of the Zeeschelde in order to help policy makers to decide upon the future of this unique estuarine system. Of all organisms retained on a 250 µm mesh-size, oligochaetes were co-dominant in the mesohaline part and the only dominant group in the tidal freshwater zone. The oligochaete fauna of the ß-mesohaline zone consisted of two brackish water tubificids, Heterochaeta costata and Tubificoides heterochaetus, and the euryhaline naidid Paranais litoralis. The freshwater species Limnodrilus hoffmeisteri penetrated as far as Boerenschans. Abundance in this zone is rather low with numbers increasing with exposure. The part of the oligohaline zone that coincides with the maximum turbidity zone is extremely poor in benthos, due to high physical, chemical and biological stress, with very low numbers of L. hoffmeisteri, Tubifex tubifex and P. litoralis. In the tidal freshwater section, mass populations of the tubificids L. hoffmeisteri and T. tubifex occur (peak densities of almost 3.10 6 ind m −2 , maximum biomass: 25.7 g ADW m −2 ) with lower numbers of Limnodrilus claparedeianus, Limnodrilus udekemianus and Limnodrilus profundicola mainly in the part of the Zeeschelde close to Gent where better oxygen conditions are found. Oligochaetes are more abundant in finer sediments, resulting in a clear vertical gradient with low mean values in the deeper subtidal coarse sediments and highest numbers in the upper intertidal where fluid muds consolidate. In comparison with L. hoffmeisteri, T. tubifex was more abundant in the finest sediments. Vorticellidae are more common on tails of oligochaetes in the oxygenenriched part (4-9%) than in the oxygen-deficient zone (< 0.5%). Regeneration rates, being considered as a suitable measure of predation pressure, increase with salinity and size of the worms and are highly specific. In comparison with other temperate estuarine systems, the Zeeschelde has impoverished communities with oligochaetes as the dominant taxa. Though a future improvement of the water quality will definitely result in a less productive but more varied benthic community in the freshwater tidal zone, oligochaetes will probably continue to play an important role due to sustained harsh conditions.

Intensive seabird surveying during seven years in the Belgian part of the southern North Sea reve... more Intensive seabird surveying during seven years in the Belgian part of the southern North Sea revealed the existence of a land-sea and a longitudinal gradient from the Schelde estuary in the east to the deeper, less turbid waters in the west. Piscivorous species preferring clear water and mid-to offshore conditions (auks, Kittiwake and Northern Gannet) are more abundant in the west. Divers, grebes and Larus-gulls are commoner in the more turbid waters near the mouth of the Schelde estuary. Depth and topography are less dominant as explanatory variables for the distribution of most of the 17 dominant species/taxa. Multivariate and correlative analysis of the abundance of these species could not reveal strong temporal or spatial coherence of seabirds in communities. Highest correlations were found among Larus-gulls scavenging at trawlers, and in the group of auks, Kittiwake and Little Gull. The auks (Razorbill, Common Guillemot) and both gull species were often seen in short-lived multi-species feeding associations over presumed fish shoals. Razorbill is the species that associated most frequently (in 28% of all observations) and it appeared to be a more 'attractive' target for Kittiwake (34%) and Little Gull (23%) than the Common Guillemot. Kleptoparasitic behaviour was rarely observed (2.9-6.3% of the observations in skuas). The impact of fishery activities on the distribution of scavenging seabirds (8 of the 17 dominant species) is large. Some 65-70% of all large gulls in the study area were observed in association with trawlers. The general patterns of distribution described in this paper provide the basis for new future research. Major emphasis should go to the interactions between hydrography, prey-availability (pelagic fish) and the specific geomorphologic characteristics of this study-area. Priority species for more detailed research are proposed.

Microbial Ecology, 2013

The oceans and coastal seas provide mankind with many benefits including food for around a third ... more The oceans and coastal seas provide mankind with many benefits including food for around a third of the global population, the air that we breathe and our climate system which enables habitation of much of the planet. However, the converse is that generation of natural events (such as hurricanes, severe storms and tsunamis) can have devastating impacts on coastal populations, while pollution of the seas by pathogens and toxic waste can cause illness and death in humans and animals. Harmful effects from biogenic toxins produced by algal blooms (HABs) and from the pathogens associated with microbial pollution are also a health hazard in seafood and from direct contact with water. The overall global burden of human disease caused by

Marine Pollution Bulletin, 2002

Oil-pollution monitoring at sea through beach bird surveying would undoubtedly benefit from a fur... more Oil-pollution monitoring at sea through beach bird surveying would undoubtedly benefit from a further standardisation of methods, enhancing the efficiency of data collection.

Hydrobiologia, 1994

To evaluate the effects of the construction of a storm surge barrier in the Oosterschelde, long-t... more To evaluate the effects of the construction of a storm surge barrier in the Oosterschelde, long-term patterns (1979–89) in abundance and biomass of the intertidal macrozoobenthos were studied at 14 permanent stations. Additionally, data of a large-scale survey in late summer 1985 and 1989 were analysed. In this paper, patterns in general parameters are discussed.

Hydrobiologia, 1994

The construction of a storm-surge barrier in the mouth of the Oosterschelde caused important hydr... more The construction of a storm-surge barrier in the mouth of the Oosterschelde caused important hydrodynamical and morphological changes that could influence the macrobenthic populations. This paper is one in a series of five all dealing with the effects ...

The various groups of linear sand ridges off the continental coast of the southernmost part of th... more The various groups of linear sand ridges off the continental coast of the southernmost part of the North Sea (the 'Flemish Banks') have an important seabird conservation value. During an intensive seabird surveying programme from 1992 till 1998 in the Belgian part of it, eleven species were counted in numbers amounting to 1-5% of the flyway population in an area of merely 3500 km 2 . Six of them (Red-throated Diver, Common Scoter, Little Gull, Sandwich Tern, Common Tern, Little Tern) are considered as of international conservation value and were selected as focal species. Hotspots are situated on the shallow Westkustbanken, in the neighbourhood of the Zeebrugge outer harbour and on the Vlaamse Banken. In addition, during the 1990s the Zeebrugge harbour accommodated a medium-sized colony of Sandwich Tern (1650 pairs) and some of the largest colonies of Common (2260 pairs) and Little Tern (430 pairs) of NW-Europe. The present conservation status of these areas is insufficient and marine protected areas (in the widest sense) are needed to safeguard the strongholds for Belgian seabirds. Oil-sensitivity maps indicate that the most vulnerable sites are too close to some of the busiest shipping routes of the world to consider any rerouting measure. Weighing the disturbance-sensitivity of different subareas shows that only on the hotspots for divers and scoters there is a need to restrict boating activity during winter. In addition this southernmost part of the North Sea is a very important corridor for seabird migration. An estimated 1-1.3 million seabirds, with one-third being focal species for conservation, may fly through this bottleneck each year. New developments such as wind parks that might have a detrimental impact on resident as well as migrating seabirds must be carefully investigated.

Belgian Journal of Zoology

... Jan Seys1*, Henk Offringa2, Jeroen Van Waeyenberge1, Patrick Meire3 & Eckhart Kuijken1 ..... more ... Jan Seys1*, Henk Offringa2, Jeroen Van Waeyenberge1, Patrick Meire3 & Eckhart Kuijken1 ... In Belgium the first occasional counts of beached birds go back as far as the 1950s and early 1960s (KESTELOOT 1953, HAUTEKIET 1955, 1956, 1961, 1965, DE RIDDER 1961 ...

There is a growing cause for concern on envenoming European species because of jellyfish blooms, ... more There is a growing cause for concern on envenoming European species because of jellyfish blooms, climate change and globalization displacing species. Treatment of envenomation involves the prevention of further nematocyst release and relieving local and systemic symptoms. Many anecdotal treatments are available but species-specific first aid response is essential for effective treatment. However, species identification is difficult in most cases. There is evidence that oral analgesics, seawater, baking soda slurry and 42–45 ˝ C hot water are effective against nematocyst inhibition and giving pain relief. The application of topical vinegar for 30 s is effective on stings of specific species. Treatments, which produce osmotic or pressure changes can exacerbate the initial sting and aggravate symptoms, common among many anecdotal treatments. Most available therapies are based on weak evidence and thus it is strongly recommended that randomized clinical trials are undertaken. We recommend a vital increase in directed research on the effect of environmental factors on envenoming mechanisms and to establish a species-specific treatment. Adequate signage on jellyfish stings and standardized first aid protocols with emphasis on protective equipment and avoidance of jellyfish to minimize cases should be implemented in areas at risk.

Trends in oil pollution in the southernmost (Belgian) part of the North Sea were analysed using a... more Trends in oil pollution in the southernmost (Belgian) part of the North Sea were analysed using a dataset of 37 years (1962-99) of annual national beached bird surveys conducted in February each year. The most abundant seabird groups represented in the beached birds were auks (31%), gulls (28%), scoters (17%) and Kittiwake (9%). Oil rates of most bird species/taxa indicate

Heb je je wel eens afgevraagd waarom de zandbank 'Trapegeer' zo heet, of hoe de 'kabeljauw' aan z... more Heb je je wel eens afgevraagd waarom de zandbank 'Trapegeer' zo heet, of hoe de 'kabeljauw' aan zijn naam gekomen is? Of ben je veeleer benieuwd naar de persoon achter de 'Thorntonbank' of naar de ontstaansgeschiedenis van de maritieme term 'kraaienest'? Geen nood, wij zochten de betekenis van de meest intrigerende zeewoorden voor je op en presenteren hieruit per editie van De Grote Rede twee termen: telkens één naam van een zandbank of geul op zee, en één niet-toponiem. Met de hulp van een experten-team waagt De Grote Rede zich op het gladde ijs van de historische en etymologische woordverklaring en laat je meegenieten van de 'best professional judgment' van deze zeewoordenaars.

Aquatic Oligochaetes, 1999

The benthic fauna of the Belgian part of the polluted Schelde estuary, called the Zeeschelde, was... more The benthic fauna of the Belgian part of the polluted Schelde estuary, called the Zeeschelde, was studied in September-October 1996 at 143 stations along 35 transects. This study is part of the OMES research program, funded by the Flemish Government, to build an ecosystem model of the Zeeschelde in order to help policy makers to decide upon the future of this unique estuarine system. Of all organisms retained on a 250 µm mesh-size, oligochaetes were co-dominant in the mesohaline part and the only dominant group in the tidal freshwater zone. The oligochaete fauna of the ß-mesohaline zone consisted of two brackish water tubificids, Heterochaeta costata and Tubificoides heterochaetus, and the euryhaline naidid Paranais litoralis. The freshwater species Limnodrilus hoffmeisteri penetrated as far as Boerenschans. Abundance in this zone is rather low with numbers increasing with exposure. The part of the oligohaline zone that coincides with the maximum turbidity zone is extremely poor in benthos, due to high physical, chemical and biological stress, with very low numbers of L. hoffmeisteri, Tubifex tubifex and P. litoralis. In the tidal freshwater section, mass populations of the tubificids L. hoffmeisteri and T. tubifex occur (peak densities of almost 3.10 6 ind m −2 , maximum biomass: 25.7 g ADW m −2 ) with lower numbers of Limnodrilus claparedeianus, Limnodrilus udekemianus and Limnodrilus profundicola mainly in the part of the Zeeschelde close to Gent where better oxygen conditions are found. Oligochaetes are more abundant in finer sediments, resulting in a clear vertical gradient with low mean values in the deeper subtidal coarse sediments and highest numbers in the upper intertidal where fluid muds consolidate. In comparison with L. hoffmeisteri, T. tubifex was more abundant in the finest sediments. Vorticellidae are more common on tails of oligochaetes in the oxygenenriched part (4-9%) than in the oxygen-deficient zone (< 0.5%). Regeneration rates, being considered as a suitable measure of predation pressure, increase with salinity and size of the worms and are highly specific. In comparison with other temperate estuarine systems, the Zeeschelde has impoverished communities with oligochaetes as the dominant taxa. Though a future improvement of the water quality will definitely result in a less productive but more varied benthic community in the freshwater tidal zone, oligochaetes will probably continue to play an important role due to sustained harsh conditions.

Intensive seabird surveying during seven years in the Belgian part of the southern North Sea reve... more Intensive seabird surveying during seven years in the Belgian part of the southern North Sea revealed the existence of a land-sea and a longitudinal gradient from the Schelde estuary in the east to the deeper, less turbid waters in the west. Piscivorous species preferring clear water and mid-to offshore conditions (auks, Kittiwake and Northern Gannet) are more abundant in the west. Divers, grebes and Larus-gulls are commoner in the more turbid waters near the mouth of the Schelde estuary. Depth and topography are less dominant as explanatory variables for the distribution of most of the 17 dominant species/taxa. Multivariate and correlative analysis of the abundance of these species could not reveal strong temporal or spatial coherence of seabirds in communities. Highest correlations were found among Larus-gulls scavenging at trawlers, and in the group of auks, Kittiwake and Little Gull. The auks (Razorbill, Common Guillemot) and both gull species were often seen in short-lived multi-species feeding associations over presumed fish shoals. Razorbill is the species that associated most frequently (in 28% of all observations) and it appeared to be a more 'attractive' target for Kittiwake (34%) and Little Gull (23%) than the Common Guillemot. Kleptoparasitic behaviour was rarely observed (2.9-6.3% of the observations in skuas). The impact of fishery activities on the distribution of scavenging seabirds (8 of the 17 dominant species) is large. Some 65-70% of all large gulls in the study area were observed in association with trawlers. The general patterns of distribution described in this paper provide the basis for new future research. Major emphasis should go to the interactions between hydrography, prey-availability (pelagic fish) and the specific geomorphologic characteristics of this study-area. Priority species for more detailed research are proposed.

Microbial Ecology, 2013

The oceans and coastal seas provide mankind with many benefits including food for around a third ... more The oceans and coastal seas provide mankind with many benefits including food for around a third of the global population, the air that we breathe and our climate system which enables habitation of much of the planet. However, the converse is that generation of natural events (such as hurricanes, severe storms and tsunamis) can have devastating impacts on coastal populations, while pollution of the seas by pathogens and toxic waste can cause illness and death in humans and animals. Harmful effects from biogenic toxins produced by algal blooms (HABs) and from the pathogens associated with microbial pollution are also a health hazard in seafood and from direct contact with water. The overall global burden of human disease caused by

Marine Pollution Bulletin, 2002

Oil-pollution monitoring at sea through beach bird surveying would undoubtedly benefit from a fur... more Oil-pollution monitoring at sea through beach bird surveying would undoubtedly benefit from a further standardisation of methods, enhancing the efficiency of data collection.

Hydrobiologia, 1994

To evaluate the effects of the construction of a storm surge barrier in the Oosterschelde, long-t... more To evaluate the effects of the construction of a storm surge barrier in the Oosterschelde, long-term patterns (1979–89) in abundance and biomass of the intertidal macrozoobenthos were studied at 14 permanent stations. Additionally, data of a large-scale survey in late summer 1985 and 1989 were analysed. In this paper, patterns in general parameters are discussed.

Hydrobiologia, 1994

The construction of a storm-surge barrier in the mouth of the Oosterschelde caused important hydr... more The construction of a storm-surge barrier in the mouth of the Oosterschelde caused important hydrodynamical and morphological changes that could influence the macrobenthic populations. This paper is one in a series of five all dealing with the effects ...

The various groups of linear sand ridges off the continental coast of the southernmost part of th... more The various groups of linear sand ridges off the continental coast of the southernmost part of the North Sea (the 'Flemish Banks') have an important seabird conservation value. During an intensive seabird surveying programme from 1992 till 1998 in the Belgian part of it, eleven species were counted in numbers amounting to 1-5% of the flyway population in an area of merely 3500 km 2 . Six of them (Red-throated Diver, Common Scoter, Little Gull, Sandwich Tern, Common Tern, Little Tern) are considered as of international conservation value and were selected as focal species. Hotspots are situated on the shallow Westkustbanken, in the neighbourhood of the Zeebrugge outer harbour and on the Vlaamse Banken. In addition, during the 1990s the Zeebrugge harbour accommodated a medium-sized colony of Sandwich Tern (1650 pairs) and some of the largest colonies of Common (2260 pairs) and Little Tern (430 pairs) of NW-Europe. The present conservation status of these areas is insufficient and marine protected areas (in the widest sense) are needed to safeguard the strongholds for Belgian seabirds. Oil-sensitivity maps indicate that the most vulnerable sites are too close to some of the busiest shipping routes of the world to consider any rerouting measure. Weighing the disturbance-sensitivity of different subareas shows that only on the hotspots for divers and scoters there is a need to restrict boating activity during winter. In addition this southernmost part of the North Sea is a very important corridor for seabird migration. An estimated 1-1.3 million seabirds, with one-third being focal species for conservation, may fly through this bottleneck each year. New developments such as wind parks that might have a detrimental impact on resident as well as migrating seabirds must be carefully investigated.

Belgian Journal of Zoology

... Jan Seys1*, Henk Offringa2, Jeroen Van Waeyenberge1, Patrick Meire3 & Eckhart Kuijken1 ..... more ... Jan Seys1*, Henk Offringa2, Jeroen Van Waeyenberge1, Patrick Meire3 & Eckhart Kuijken1 ... In Belgium the first occasional counts of beached birds go back as far as the 1950s and early 1960s (KESTELOOT 1953, HAUTEKIET 1955, 1956, 1961, 1965, DE RIDDER 1961 ...