Search results for "Fishe"
showing 10 items of 2001 documents
Local cod (Gadus morhua) revealed by egg surveys and population genetic analysis after longstanding depletion on the Swedish Skagerrak coast
2018
Abstract Dramatic and persistent reductions in Atlantic cod (Gadus morhua) are common in many coastal areas. While offshore cod stocks still were abundant and productive, the Swedish west coast showed signs of diminishing adult cod abundance at the beginning of the 1980s, where the local cod component was considered to be extirpated. To survey the present cod spawning activity and stock composition, we initiated egg trawling over two consecutive years (203 hauls in total) in combination with population genetic analyses (425 individually genotyped eggs). Here, we provide evidence of cod spawning at the Swedish Skagerrak coast, suggesting recolonization or that local cod has recovered from a …
Who is fishing on what stock: population-of-origin of individual cod (Gadus morhua) in commercial and recreational fisheries
2018
AbstractAtlantic cod (Gadus morhua) in Skagerrak are structured into distinct ecotypes or stock components that have been severely depleted over the past decades. To improve our understanding of how local commercial and recreational fisheries influence cod stocks, we investigated whether these user groups target different stock components of cod. Cod were sampled from the recreational rod and line fishery and from commercial shrimp trawlers catching cod as by-catch. Based on a large set of single nucleotide polymorphisms (SNPs), we defined a subset of 27 semi-diagnostic SNPs designed to discriminate between two cod stock components: “inner fjord” cod and “North Sea” cod, designated by their…
En quin grau afecten les pseudociències a la comunitat educativa?
2018
Pseudosciences are present and accepted naturally by broad sectors of the population. Despite their potential risks, they are not taken into account when teaching science; some universities have even offered official pseudoscientific courses. In this text we want to learn about the degree of acceptance of these beliefs in high-school science teachers in training, who have been detected to have significant levels of acceptance of pseudoscience.
Modelling binary mixtures of herbicides in populations resistant to one of the components: evaluation for resistance management
2008
BACKGROUND: Herbicide mixtures are commonly proposed to delay the selection of herbicide resistance in susceptible populations (called the SM strategy). However, in practice, herbicide mixtures are often used when resistance to one of the two active ingredients has already been detected in the targeted population (called the RM strategy). It is doubtful whether such a practice can select against resistance, as the corresponding selection pressure is still exerted. As a consequence, the effect of mixtures on the evolution of an already detected resistance to one of the herbicides in the combination remains largely unexplored. In the present work, a simple model was developed to explore furth…
Unpredicted ecological and ecosystem services of biodiversity. Spontaneous vegetation, hedgerows, and maple trees as useful landscape components to i…
2020
Abstract Rural landscapes have been dramatically simplified and reduced. Large mechanical machinery was adopted and most of the natural helps such as living tutors in the vineyards disappeared or were replaced by cement or steel pillars. In the same way, field margins and hedgerows have also become restricted and simplified. The vegetation in the rural landscape mosaic provides alternative food and overwintering places, maintaining the inestimable importance of biodiversity in providing unexpected ecological services in agroecosystems. An important example could be predatory mites both as species and population density, providing ecological service for biological control such as the two-spo…
Pervasive declines in monkfish (Lophius americanus) size structure throughout the northwest Atlantic
2020
Abstract Shifts in size structure have been documented for many commercially exploited marine fish stocks, thought to be attributed to size-selective harvesting practices coupled with changing oceanic conditions. Northwest Atlantic monkfish (Lophius americanus) is a commercially valued species in the United States that is commonly caught as bycatch in Canadian scallop and groundfish fisheries. This uniquely positioned stock is bisected by the Canadian–American jurisdictional boundary, with considerable differences in exploitation and management across its range. The status of this species was assessed two decades ago (2000) in the Maritimes region of Canada and more recently (2016) in the U…
Occurrence and impact of interactions between small-scale fisheries and predators, with focus on Mediterranean monk seals (Monachus monachus Hermann …
2017
Abstract Antagonistic interaction between Mediterranean marine mammals, including the endangered monk seal ( Monachus monachus ), and small-scale fisheries is a growing problem in the Aegean Sea. Effective management measures are needed to ensure both the survival of the monk seal population, and its coexistence with the small-scale fisheries. In this study, data from 371 fishing journeys by 8 different boats was collected between March and November 2014. Evidence of depredation by monk seals was recorded in 19.1% of fishing journeys, by cetaceans in 5%, and by other predators in 16.5%. Analysis of landings data showed that gear and depth were the variables most likely to influence the occu…
Demographic responses to protection from harvesting in a long-lived marine species
2021
Abstract Marine protected areas (MPAs) are usually considered to have positive effects on the recovery of over-exploited populations. However, resolving the extent to which MPAs function according to their conservation goals requires that essential demographic information such as individual survival and population size are quantified. To this end, we analyzed a 16-year replicated mark-recapture study on European lobster (Homarus gammarus, n = 8793) conducted at several protected and unprotected sites in southern Norway, quantifying the impact of MPAs on local population dynamics by means of a “before-after control-impact” study approach (BACI). Lobster survival and abundance were estimated …
Harvesting changes mating behaviour in European lobster
2018
Removing individuals from a wild population can affect the availability of prospective mates and the outcome of competitive interactions, with subsequent effects on mating patterns and sexual selection. Consequently, the rate of harvest‐induced evolution is predicted to be strongly dependent on the strength and dynamics of sexual selection, yet there is limited empirical knowledge on the interplay between selective harvesting and the mating systems of exploited species. In this study, we used genetic parentage assignment to compare mating patterns of the highly valued and overexploited European lobster (Homarus gammarus) in a designated lobster reserve and nearby fished area in southern Nor…
Editorial: Legumes for global food security
2020
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