Populacije meduza u Sredozemnom moru

Knowledge of jellyfish populations in the Mediterranean Sea is rather extensive, due to a combination of long-term datasets and interest relating to impacts on human activities. The notorious jellyfish Pelagia noctiluca appears to be blooming with increased frequency in some areas, and may sting tens of thousands of sea bathers in a single year. In addition, a number of invasive species of jellyfish appear to be thriving in the Mediterranean, some of which have significant impacts on fishing and other industries. In contrast, other groups of jellyfish show variable trends over time, and may be of little interest to the public. Here, we summarize knowledge of jellyfish in the Mediterranean Sea, including temporal trends for a variety of species, and discuss possible anthropogenic causes of increased jellyfish abundance and management interventions in the face of uncertainty.Saznanja o populacijama meduza u Sredozemnom moru su prilično opsežna zahvaljujući dugoročnim setovima podataka i interesa u svezi njihovog utjecaja na ljudske aktivnosti. zloglasna meduza Pelagia noctiluca čija je povećana učestalost u nekim područjima, a mogu opeći nekoliko desetaka tisuća morskih kupača u jednoj godini. Osim toga, broj invazivnih vrsta meduza je u usponu u Sredozemlju, od kojih neke imaju značajan utjecaj na ribarstvo i ostale industrije. Za razliku od drugih grupa meduza pokazuju različite trendove tijekom vremena pa zbog toga nisu od velikog interesa za javnost. U ovom radu smo prikazali sažeto znanje o meduzama u Sredozemnom moru, uključujući i vremenske trendove za razne vrste, te raspravili moguće antropogene uzroke povećanja brojnost i meduza i upravljanje intervencijama usprkos neizvjesnosti

Jellyfish fisheries of the world

Fisheries for jellyfish (primarily scyphomedusae) have a long history in Asia, where people have been catching and processing jellyfish as food for centuries. More recently, jellyfish fisheries have expanded to the Western Hemisphere, often driven by demand from buyers in Asia as well as collapses of more traditional local finfish and shellfish stocks. Despite this history and continued expansion, jellyfish fisheries are understudied, and relevant information is sparse and disaggregated. Catches of jellyfish are often not reported explicitly, with countries including them in fisheries statistics as “miscellaneous invertebrates” or not at all. Research and management of jellyfish fisheries is scant to nonexistent. Processing technologies for edible jellyfish have not advanced, and present major concerns for environmental and human health. Presented here is the first global assessment of jellyfish fisheries, including identification of countries that catch jellyfish, as well as which species are targeted. A global catch reconstruction is performed for jellyfish landings from 1950 to 2013, as well as an estimate of mean contemporary catches. Results reveal that all investigated aspects of jellyfish fisheries have been underestimated, including the number of fishing countries, the number of targeted species, and the magnitudes of catches. Contemporary global landings of jellyfish are at least 750,000 tonnes annually, more than double previous estimates. Jellyfish have historically been understudied, resulting in the current dearth of knowledge on population dynamics and jellyfish fishery management. However, many of the tools used in traditional fisheries science, such as length-frequency analysis, can be applied to jellyfish, as demonstrated herein. Research priorities are identified, along with a prospective outlook on the future of jellyfish fisheries.Science, Faculty ofGraduat

Changing jellyfish populations : trends in large marine ecosystems

Although there are various indications and claims that jellyfish have been increasing at a global scale in recent decades, a rigorous demonstration to this effect has never been presented. As this is mainly due to scarcity of quantitative time series of jellyfish abundance from scientific surveys, an attempt is presented here to complement such data with non-conventional information from other sources. This was accomplished using the analytical framework of fuzzy logic, which allows the combination of information with variable degrees of cardinality, reliability, and temporal and spatial coverage. Data were aggregated and analysed at the scale of Large Marine Ecosystem (LME). Of the 66 LMEs defined thus far, which cover the world’s coastal waters and seas, trends of jellyfish abundance (increasing, decreasing, or stable/variable) were identified (occurring after 1950) for 45, with variable degrees of confidence. Of these 45 LMEs, the overwhelming majority (31 or 69%) showed increasing trends. Recent evidence also suggests that the observed increases in jellyfish populations may be due to the effects of human activities, such as overfishing, global warming, pollution, and coastal development. Changing jellyfish populations were tested for links with anthropogenic impacts at the LME scale, using a variety of indicators and a generalized additive model. Significant correlations were found with several indicators of ecosystem health, as well as marine aquaculture production, suggesting that the observed increases in jellyfish populations are indeed due to human activities and the continued degradation of the marine environment.Science, Faculty ofEarth, Ocean and Atmospheric Sciences, Department ofGraduat

Fisheries Centre research reports, Vol. 19, no. 5

DIRECTOR'S FORWARD. ABSTRACT. INTRODUCTION. Definition of "Jellyfish". Problem Statement. Challenges of Studying Jellyfish Populations. Impacts of Jellyfish Blooms. Invasive Species. MATERIALS AND METHODS. Large Marine Ecosystem Approach. 1950 Baseline. The Jellyfish Chronicles. Data Selection. Abundance Trend. Scoring Chronicles. Identifying Invasive Species. Fuzzy Expert System. Uncertainty. RESULTS. Effects of Invasive Species. Effects of Jellyfish Overexploitation. DISCUSSION. Defining an ‘Increase’. Species Invasions. Taxonomic Concerns. LME #1 – East Bering Sea. LME #2 – Gulf of Alaska. LME #3 – California Current. LME #4 – Gulf of California. LME #5 – Gulf of Mexico. LME #6 – Southeast U.S. Continental Shelf. LME #7 – Northeast U.S. Continental Shelf. LME #8 – Scotian Shelf. LME #9 – Newfoundland-Labrador Shelf. LME #10 – Insular Pacific-Hawaiian. LME #11 – Pacific Central-American Coastal. LME #12 – Caribbean Sea. LME #13 – Humboldt Current. LME #14 – Patagonian Shelf. LME #15 – South Brazil Shelf. LME #16 – East Brazil Shelf. LME #18 – West Greenland Shelf. LME #21 – Norwegian Sea. LME #22 – North Sea. LME #23 – Baltic Sea. LME #24 – Celtic-Biscay Shelf. LME #25 – Iberian Coastal. LME #26 – Mediterranean Sea. LME #28 – Guinea Current. LME #29 – Benguela Current. LME #30 – Agulhas Current. LME #31 – Somali Coastal Current. LME #32 – Arabian Sea. LME #34 – Bay of Bengal. LME #35 – Gulf of Thailand. LME #36 – South China Sea. LME #40 – Northeast Australian Shelf. LME #41 – East Central Australian Shelf. LME #42 – Southeast Australian Shelf. LME #47 – East China Sea. LME #48 – Yellow Sea. LME #49 – Kuroshio Current. LME #50 – Sea of Japan. LME #51 – Oyashio Current. LME #52 – Sea of Okhotsk. LME #53 – West Bering Sea. LME #60 – Faroe Plateau. LME #61 – Antarctic. LME #62 – Black Sea. LME #63 – Hudson Bay. CONCLUSIONS. REFERENCES. APPENDICES. Appendix A - Jellyfish Chronicles. Appendix B - Belief Indexes.Fisheries Centre (FC)UnreviewedGraduat

Cnidarian venoms and alternative research methods: From cell damage to possible applications.

Cnidaria are venomous aquatic organisms, whose dangerousness is remarkable among marine species. Cnidarian jellyfish sometimes show extensive proliferations \u2013 outbreaks or blooms \u2013 along with occasional strandings on beaches. Due to the invisibility of several diaphanous and completely transparent species, sometimes they are not seen by bathers or sea-workers, resulting in envenomations with consequent local or systemic implications such as contact dermatitis, neurotoxicity, cardiotoxicity and, in serious cases, anaphylaxis. Researchers have historically focused their efforts on the identification of stings, evaluating the shape of lesions, the marks left on the skin, and the etiology of illness, in order to find methods useful to inactivate venoms and to develop care systems aimed at the mitigation of pain, swelling, redness, and systemic consequences. In the interest of better knowing the toxic mechanisms consequent to cnidarian stinging, beginning in the 1990s, research focused on studying the effects of venoms at a cellular level. Since then, a considerable number of papers have provided data about the mechanisms of action of venoms and the associated impacts on cell survival, growth, and metabolism. Subsequently, the utilization of compounds present in jellyfish venoms, both for therapeutical purposes and to counter cell proliferation, has been considered. This paper aims to review the current knowledge about the activity of jellyfish venoms at the cellular level, with a double prospect: i) to implement alternative methods to study cnidarian venoms and ii) to evaluate current opportunities for the therapeutical use of cnidarian extracts

Impacts and effects of ocean warming on jellyfish

Representatives of gelatinous zooplankton are increasingly reported in large numbers, with more than 1000 species worldwide, including Cnidaria, Ctenophora and Thaliacea, often collectively known as “jellyfish”. • The reasons for increasing jellyfish blooms are probably manifold, ranging from local to global. Climate change and overfishing are global phenomena, and are good candidates as primary drivers of the rise of gelatinous zooplankton, at least in some parts of the ocean. • Current evidence suggests that sea warming is forcing temperate marine biota towards the poles, with tropicalization of temperate marine ecosystems due to community phase shifts. Climate change is also negatively affecting tropical communities, as exemplified by the increasing frequency of coral bleaching events. Gelatinous zooplankton appear to be expanding their distributions, as seen in the Mediterranean Sea with the increased presence of tropical species, likely favoured by both temperature increases and the progressive enlargement of the Suez Canal. • There is no evidence that temperature rises are threatening tropical jellyfish species, as they are with corals, but this might be due to current lack of observations. • Increases in temperature may broaden the reproductive periods of mid-latitude jellyfish, and improve winter survival of tropical species expanding to temperate waters, therefore boosting both alien and native outbreaks. • Increases in temperature at high latitudes might be detrimental for indigenous species, reducing their reproductive outputs. So far, limited increases in temperature at high latitudes do not support the proliferation of warm-water, non-indigenous species. • The resulting patterns should see a stable situation at low and high latitudes, with no tendency to gelatinous plankton blooms, whereas these phenomena should increase at mid-latitudes, but this speculation needs to be substantiated by focused studies

Blooms: Interactions with Humans and Fisheries

Ó The Author(s) 2012. This article is published with open access at Springerlink.com Abstract Although there are various indications and claims that jellyfish (i.e., scyphozoans, cubozoans, most hydrozoans, ctenophores, and salps) have been increasing at a global scale in recent decades, a rigorous demonstration of this has never been presented. Because this is mainly due to scarcity of quantitative time series of jellyfish abundance from scientific surveys, we attempt to complement such data with non-conventional information from other sources. This was accomplished using the analytical framework of fuzzy logic, which allows th