Ghost fishing efficiency by lost, abandoned or discarded pots in snow crab (Chionoecetes opilio) fishery.

Marine pollution by lost, abandoned or otherwise discarded fishing gear (ALDFG) often has negative impact on the ecosystem through plastic pollution and continuous capture of marine animals, so-called "ghost fishing". ALDFG in pot fisheries is associated with high ghost fishing risk. The snow crab (Chionoecetes opilio) pot fishery is conducted in harsh weather conditions increasing the risk of fishing gear loss.

Effect of gillnet twine thickness on capture pattern and efficiency in the Northeast-Arctic cod (Gadus morhua) fishery.

Gillnets are among the most common fishing gears worldwide. They are often made of thin twine, which is prone to wear and tear, limiting the lifespan of the gillnet. This increases gillnet turnover, and consequently increased risk of gear discarding, gear loss, ghost fishing and marine pollution.

Effect of the Nordmøre grid bar spacing on size selectivity, catch efficiency and bycatch of the Barents Sea Northern shrimp fishery.

The introduction of the Nordmøre grid in shrimp trawls has reduced the bycatch of non-target species. In the Norwegian Northern shrimp (Pandalus borealis) fishery, the mandatory selective gear consists of a Nordmøre grid with 19 mm bar spacing combined with a 35 mm mesh size diamond mesh codend. However, fish bycatch in shrimp trawls remains a challenge and further modifications of the gear that can improve selectivity are still sought.

Quantification of gear inflicted damages on trawl-caught haddock in the Northeast Atlantic fishery.

External damages are indicators of the overall quality of fish and fish welfare. Haddock is an important commercial species widespread in the North Atlantic, but few studies related to quality have been carried out on this species. We studied the levels of external damages on haddock captured with a demersal trawl in the Northeast Atlantic.

Quantification of bell-shaped size selectivity in shrimp trawl fisheries using square mesh panels and a sorting cone after a Nordmøre grid.

Shrimp trawlers in the Barents Sea use a Nordmøre sorting grid ahead of a small-mesh codend to avoid bycatch while catching shrimps efficiently. However, small fish can still pass through the grid to enter the codend, which increases their risk of being retained. In this study, we quantified the selectivity of a standard Nordmøre grid used together with one of two different codend designs, namely a diamond mesh codend with square mesh panels and a codend with a square mesh sorting cone section, for deep-water shrimp (Pandalus borealis), redfish (Sebastes spp.

Catch and release patterns for target and bycatch species in the Northeast Atlantic deep-water shrimp fishery: Effect of using a sieve panel and a Nordmøre grid.

The Nordmøre grid and the sieve panel are two of the main devices used to reduce fish bycatch in trawl fisheries targeting shrimp species. However, even when using such devices, some small-sized fish enter the codend of the trawl together with the targeted shrimp. Therefore, bycatch reduction remains a problem in some shrimp fisheries.

Sequential codend improves quality of trawl-caught cod.

Trawl-caught fish are frequently associated with deteriorated catch quality. This study presents a new dual sequential codend concept with the aim of improving the quality of trawl-caught fish by minimizing the frequency and severity of catch damage. During towing, the fish are retained in an anterior codend segment with the legislated mesh size.

Aspects of the epidemiology, research, and control of lentiviral infections of small ruminants and their relevance to Dutch sheep and goat farming.

In 1862, the veterinarian Loman reported the first sheep in The Netherlands with symptoms associated with lentiviral infection, although at the time the symptoms were ascribed to ovine progressive pneumonia. In the following century, similar cases were reported by South African, French, American, and Icelandic researchers. Extensive research into the pathology, aetiology, and epidemiology of this slowly progressive and ultimately fatal disease was initiated in several countries, including the Netherlands.

Diagnostic performance of ELISA and PCR in identifying SRLV-infected sheep and goats using serum, plasma and milk samples and in early detection of infection in dairy flocks through bulk milk testing.

The objective of the study was to evaluate the diagnostic performances of the ELITEST-MVV ELISA for detection of antibodies against small ruminant lentiviruses and of two recently published PCRs for the detection of proviral DNA of SRLV in blood and corresponding individual milk samples. In addition, the feasibility of bulk milk testing was investigated by titrating ELISA positive pooled milk samples in negative milk, and by investigating bulk milk samples by ELISA and PCR in relation to the SRLV-status of the flocks. The results show that plasma and milk are suitable replacements for serum.

Use of serology and polymerase chain reaction for the rapid eradication of small ruminant lentivirus infections from a sheep flock: a case report.

A SRLV-free sheep flock incurred infection which led to an SRLV infection rate of over 50% of the ewes (34/64) within a 30 months period, indicating that environmental conditions were favourable to transmission. An intensive regimen of sampling at short intervals and testing for SRLV antibodies and proviral DNA combined with strict management was implemented for the entire flock, lambs and yearlings included. This resulted in eradication of the infection within two testing and culling rounds with a 3 months interval.

Specific detection of small ruminant lentiviral nucleic acid sequences located in the proviral long terminal repeat and leader-gag regions using real-time polymerase chain reaction.

Real-time polymerase chain reaction (RT-PCR) detection of proviral nucleic acid sequences of small ruminant lentiviruses (SRLV) in blood samples was developed and evaluated. Priming oligonucleotides were designed on the highly conserved 5' untranslated leader-gag region while those on the long terminal repeat (LTR) assay were derived from literature. DNA was extracted from the buffycoat interlayer of centrifuged blood samples.

Presence of pro-lentiviral DNA in male sexual organs and ejaculates of small ruminants.

To be able to predict sexual transmissibility of small ruminant lenti viruses (SRLV), it is necessary to know whether or not the virus is excreted in the semen, and under what circumstances. Thus, this research focussed on establishing the presence of proviral DNA of SRLV in semen and in the male genital tract of small ruminants. After initial results established the presence of SRLV in serum, the emergence of proviral DNA of SRLV in semen and presence in blood in a group of naturally SRLV-infected individuals (13 rams and 4 bucks), was followed temporally using real-time polymerase chain reaction (PCR).

Evaluation of five enzyme-linked immunosorbent assays and an agar gel immunodiffusion test for detection of antibodies to small ruminant lentiviruses.

In the framework of the Dutch control program for small ruminant lentiviral (SRLV) infections, too many drawbacks were encountered with respect to serological testing. To improve the quality of testing, five enzyme-linked immunosorbent assays (ELISAs) and an agar gel immunodiffusion test (AGIDT) were evaluated. The focus was on the sensitivity, specificity, and variances of the commercially available tests.

The effect of maternal antibodies on the detection of bovine virus diarrhoea virus in peripheral blood samples.

Persistently infected animals (PI animals), that is those animals born after an intrauterine infection of the dam during the first 120 days of gestation, are the main source of bovine virus diarrhoea virus (BVD virus) in a cattle population. The success of any BVD virus eradication programme depends on the ability to detect all PI animals at a young age. The purpose of this study was to evaluate the use of the antigen ELISA test and the reverse transcriptase-polymerase chain reaction (RT-PCR) test for the diagnosis of PI animals in the presence of maternal antibodies, and to compare them with the classical virus isolation test.

Failure of foetal protection after vaccination against an experimental infection with bovine virus diarrhea virus.

A protocol is described to measure the protection of the bovine fetus against an experimental bovine virus diarrhea virus (BVDV) infection after vaccination. Two inactivated experimental vaccines were applied twice with a 3 week interval. A mixture of three different Dutch field strains was used as challenge on mainly the 82nd day of gestation to vaccinated and unvaccinated control animals.

A comparison of four serological tests for the diagnosis of caseous lymphadenitis in sheep and goats.

A double antibody sandwich ELISA (ELISA A) developed for the detection of Corynebacterium pseudotuberculosis infection in sheep and goats was modified to improve its sensitivity. To establish the sensitivity and specificity of this modified ELISA (ELISA B), sera from 183 sheep and 186 goats were tested using ELISAs A and B. Comparison was also made with two further ELISAs (C and D) developed in Australia that, respectively, detect antibodies to cell wall antigens or toxin.

Differentiation and genomic and antigenic variation among fetal, respiratory, and neurological isolates from EHV1 and EHV4 infections in The Netherlands.

Ten monoclonal antibodies (MAbs) were produced against equine herpes virus type 1 (EHV1). Two appeared type-specific, while the other eight were directed against epitopes common to both EHV1 and EHV4. Two MAbs directed against the glycoprotein gp2 recognized linear epitopes, as demonstrated by Western blotting.

An equine herpesvirus 1 (EHV1) abortion storm at a riding school.

An outbreak of EHV1 abortions occurred at a riding school in The Netherlands in 1991. Seven of twelve pregnant mares aborted, and another foal died at 8 days of age. Six abortions occurred within 12 days in March after an initial abortion on 8 February.

Seroepidemiological evidence for a relationship between Neospora caninum infections in dogs and cattle.

Dogs from dairy farms with a known prevalence of Neospora caninum antibodies in the cattle were examined for the presence of N. caninum antibodies using an ELISA. Data of farm dogs were compared with those of dogs examined at a university clinic, which originated mainly in urban areas.

A simple, rapid and reliable enzyme-linked immunosorbent assay for the detection of bovine virus diarrhoea virus (BVDV) specific antibodies in cattle serum, plasma and bulk milk.

To detect Bovine Virus Diarrhoea Virus (BVDV)-specific antibodies in cattle serum, plasma and bulk milk, a simple, reliable and rapid blocking ELISA ("Ceditest") has been developed using two monoclonal antibodies ("WB112" and "WB103") directed to different highly conserved epitopes on the non-structural peptide NS3 of pestiviruses. The test can be performed at high reproducibility using undiluted samples. In testing 1000 field serum samples, the ELISA showed a specificity and a sensitivity relative to the virus neutralization test of 99% and 98%, respectively.

Serodiagnosis of neosporosis in individual cows and dairy herds: A comparative study of three enzyme-linked immunosorbent assays.

The performance of three enzyme-linked immunosorbent assays (ELISA) for detection of antibodies to Neospora caninum in bovine sera was evaluated by using various categories of sera. Two commercial ELISA methods, one based on chemically fixed intact tachyzoites and one based on a sonicate lysate of whole tachyzoites, were compared with an in-house ELISA based on a detergent lysate of whole tachyzoites. A brief description of the development of the latter ELISA is also given.

A comparative study of serological tests for use in the bovine herpesvirus 1 eradication programme in The Netherlands.

We compared a gB-ELISA, a gE-ELISA and a Danish test system (consisting of a blocking and an indirect ELISA) for their specificity and sensitivity to detect antibodies against BHV1. The Danish test system showed the highest sensitivity and the gE-ELISA the lowest; the gB-ELISA showed an intermediate sensitivity. If the doubtful zone (25-50% blocking) of the gB-ELISA was considered as positive (gB-ELISA+), the sensitivity almost reached that of the Danish test system.

Comparative study on four enzyme-linked immunosorbent assays and a cocultivation assay for the detection of antigens associated with the bovine viral diarrhoea virus in persistently infected cattle.

Four commercially available ELISAs for detection of antigens associated with the bovine viral diarrhoea virus in persistently infected cattle have been compared. The tests are equally specific (100%) and the sensitivity of three ELISAs is comparable with that of a conventional cocultivation assay. Performing ELISA on samples from young animals that received colostrum may yield false negative results because of interference of maternal antibodies in the tests.

Activation of complement by bovine respiratory syncytial virus-infected cells.

Because complement activation is probably involved in the pathogenesis of as well as in recovery from the disease induced by bovine respiratory syncytial virus (BRSV), we studied the activation of complement by BRSV-infected cells in vitro in a homologous system. Binding of C3 on the surface of infected cells was measured in a biotin-streptavidin amplified ELISA, and complement-mediated lysis was measured in a 51Cr release assay. Without antibody, infected cells activated and bound more C3 than uninfected cells.

Analysis of the antibody response to bovine respiratory syncytial virus proteins in calves.

The antibody response in calves to natural infections with bovine respiratory syncytial virus (BRSV) was analysed by radioimmunoprecipitation assays. Antibodies to virus proteins of Mr 200K (L), 87K (G), 46K (F1), 41K (N), 35K (P), 28K and 24K (F2), 27K (M), 22K and less than 14K could be identified. Recovery of 6- to 7-month-old calves from severe BRSV-associated disease was accompanied by the development of an antibody response to the virus, which was directed mainly o the F and N proteins.