Search results for "Fishe"
showing 10 items of 2001 documents
Trophic cascades in benthic marine ecosystems: lessons for fisheries and protected-area management
2000
An important principle of environmental science is that changes in single components of systems are likely to have consequences elsewhere in the same systems. In the sea, food web data are one of the few foundations for predicting such indirect effects, whether of fishery exploitation or following recovery in marine protected areas (MPAs). We review the available literature on one type of indirect interaction in benthic marine ecosystems, namely trophic cascades, which involve three or more trophic levels connected by predation. Because many indirect effects have been revealed through fishery exploitation, in some cases we include humans as trophic levels. Our purpose is to establish how wi…
Combining population genomics with demographic analyses highlights habitat patchiness and larval dispersal as determinants of connectivity in coastal…
2022
Gene flow shapes spatial genetic structure and the potential for local adaptation. Among marine animals with nonmigratory adults, the presence or absence of a pelagic larval stage is thought to be a key determinant in shaping gene flow and the genetic structure of populations. In addition, the spatial distribution of suitable habitats is expected to influence the distribution of biological populations and their connectivity patterns. We used whole genome sequencing to study demographic history and reduced representation (double-digest restriction associated DNA) sequencing data to analyse spatial genetic structure in broadnosed pipefish (Syngnathus typhle). Its main habitat is eelgrass beds…
Alcione e l'alcione. Archeologia del mito: nuclei tematici, funzioni simboliche, storia di contaminazioni
2021
Lo studio prende in considerazione le più antiche testimonianze della letteratura greca riguardanti il mito di Alcione e dell’uccello omonimo, per tentare di enuclearne funzione culturale e nuclei tematici originari. Rientrano nel quadro dell’analisi considerazioni sulla figura di Cleopatra Alcione in Hom. Il. 9, 561, sulle stratificazioni del mito post-omeriche con particolare riguardo per la tradizione esiodea del mito, con un’analisi del fr. 26 Davies di Alcmane (cerili e alcioni) nonché del fr. 508 Page di Simonide, quest’ultimo valutato rispetto agli aspetti ornitologici del mito (i giorni alcionii). Chiude l’indagine una proposta di interpretazione etimologica del nome Alcione (connes…
Browsing hinders the regeneration of broadleaved trees in uneven-aged forest management in southern Finland
2020
Uneven-aged forest management has attained increasing popularity. It may benefit biodiversity, buffer against pests and abiotic damages, decrease runoff from clearcuts and improve recreational values. We studied how gap cuttings and single-tree selection cuttings influence browsing damage in spruce-dominated forests in south-central Finland. Overall, browsing damage was especially frequent in aspen and rowan, but also in birch. The larger the basal area left in harvesting, the lower the browsing pressure on birch and rowan; neither the harvesting method nor the seedling density had an independent effect on browsing damage. Although larger tree retention levels may reduce browsing damage, th…
Density Decline in a Mediterranean Seahorse Population: Natural Fluctuations or New Emerging Threats?
2021
Illegal wildlife trade is considered one of the most serious threats to biodiversity worldwide, along with habitat loss/degradation and overfishing of wild stocks. Seahorses are considered at high risk as these fish represent an important component of traditional Chinese medicine but are also sold as curios and ornamental fish. On a worldwide level, illegal trade is controlled by numerous laws and regulations, but it seems to continue by assuming more dynamic routes. In the Mediterranean Sea, Hippocampus guttulatus formed one of the largest populations at Mar Piccolo di Taranto in South-Eastern Italy. During the routine monitoring of this population in 2016, a dramatic density decrease was …
The dynamics of Italian competitive positioning in the Mediterranean Bluefin tuna industry
2020
The bluefin tuna or Thunnus thynnus is one of the widely recognised fish species since ancient times. Italy is the most important players in the international arena, however, the introduction of a system of total allowable catches and other measures established by the International Commission for the Conservation of Atlantic Tunas, has deeply changed the competitive positioning of Italy. The aim of this study is to perform an analysis of the comparative advantage of Italy by using the relative trade advantage index. Findings reveal that Italy has gained a competitive advantage in the Maltese market and has suffered a loss of the historical competitive advantage in the Japanese one. Results …
Improving soil and water conservation and ecosystem services by sustainable soil management practices: From a global to an Italian soil partnership
2020
The UN Sustainable Development Goals (SDGs) identify the need to restore degraded soils in order to improve productivity and the provision of ecosystem services. The aim is to support food production, store and supply clean water, conserve biodiversity, sequester carbon, and improve soil resilience in a context of climate change. Within this framework, in order to achieve the SDGs and to correct land management in the long-term, soil management is considered mandatory. The reduction of land degradation should be based on various sustainable soil management practices that improve and maintain soil organic matter levels, increase water infiltration, and improve soil water management. This tec…
Age is not just a number : Mathematical model suggests senescence affects how fish populations respond to different fishing regimes
2021
Senescence is often described as an age-dependent increase in natural mortality (known as actuarial senescence) and an age-dependent decrease in fecundity (known as reproductive senescence), and its role in nature is still poorly understood. Based on empirical estimates of reproductive and actuarial senescence, we used mathematical simulations to explore how senescence affects the population dynamics of Coregonus albula, a small, schooling salmonid fish. Using an empirically based eco-evolutionary model, we investigated how the presence or absence of senescence affects the eco-evolutionary dynamics of a fish population during pristine, intensive harvest, and recovery phases. Our simulation …