Jellyfish Stings Trigger Gill Disorders and Increased Mortality in Farmed Sparus aurata (Linnaeus, 1758) in the Mediterranean Sea

none8siJellyfish are of particular concern for marine finfish aquaculture. In recent years repeated mass mortality episodes of farmed fish were caused by blooms of gelatinous cnidarian stingers, as a consequence of a wide range of hemolytic, cytotoxic, and neurotoxic properties of associated cnidocytes venoms. The mauve stinger jellyfish Pelagia noctiluca (Scyphozoa) has been identified as direct causative agent for several documented fish mortality events both in Northern Europe and the Mediterranean Sea aquaculture farms. We investigated the effects of P. noctiluca envenomations on the gilthead sea bream Sparus aurata by in vivo laboratory assays. Fish were incubated for 8 hours with jellyfish at 3 different densities in 300 l experimental tanks. Gill disorders were assessed by histological analyses and histopathological scoring of samples collected at time intervals from 3 hours to 4 weeks after initial exposure. Fish gills showed different extent and severity of gill lesions according to jellyfish density and incubation time, and long after the removal of jellyfish from tanks. Jellyfish envenomation elicits local and systemic inflammation reactions, histopathology and gill cell toxicity, with severe impacts on fish health. Altogether, these results shows P. noctiluca swarms may represent a high risk for Mediterranean finfish aquaculture farms, generating significant gill damage after only a few hours of contact with farmed S. aurata. Due to the growth of the aquaculture sector and the increased frequency of jellyfish blooms in the coastal waters, negative interactions between stinging jellyfish and farmed fish are likely to increase with the potential for significant economic losses.Bosch-Belmar, Mar; M'Rabet, Charaf; Dhaouadi, Raouf; Chalghaf, Mohamed; Daly Yahia, Mohamed Néjib; Fuentes, Verónica; Piraino, Stefano; Kéfi-Daly Yahia, OnsBosch Belmar, Mar; M'Rabet, Charaf; Dhaouadi, Raouf; Chalghaf, Mohamed; Daly Yahia, Mohamed Néjib; Fuentes, Verónica; Piraino, Stefano; Kéfi Daly Yahia, On

Transient effect of bisphenol A (BPA) and di-(2-ethylhexyl) phthalate (DEHP) on the cosmopolitan marine diatom Chaetoceros decipiens-lorenzianus

Incubation under controlled laboratory conditions were performed to assess the toxic effects of two plastic derived chemicals, bisphenol A (BPA) and di-(2-ethylhexyl) phthalate (DEHP), on the growth, photosynthetic efficiency and photosynthetic activity of the cosmopolitan diatom Chaetoceros decipiens-lorenzianus. Non-axenic diatom cells were exposed to concentrations of BPA and DEHP (separately and in mixture), mimicking concentrations observed in contaminated marine ecosystems, for seven days. Upon short-term exposure (i.e., during the first 48 h), BPA and DEHP induced a slight but significant stimulation of biomass and photosynthetic activity relative to the control, whereas, no significant impact was observed on the photosynthetic efficiency. Nevertheless, this pattern was transient. The stimulation was followed by a return to control conditions for all treatments at the end of incubation. These results showed that the cosmopolitan diatom Chaetoceros was not impacted by representative in situ concentrations of plastic derivatives, thus confirming its ability to thrive in coastal anthropogenic environments

Effects of Pelagia noctiluca jellyfish swarms on caged gilthead sea bream

International Council for the Exploration of the Sea Annual Science Conference (ICES ASC 2014), Sustainability in a changing ocean, 15-19 September 2014, La Coruña.-- 2 pagesIn recent years, interactions between caged finfish and jellyfish have been increasingly reported, with major fish mortalities and severe economic impacts to aquaculture facilities. The scyphomedusa Pelagia noctiluca has been responsible for documented mortality events in Eastern Atlantic (Irish Sea) and the Mediterranean Sea. We investigated he impact of P. noctiluca stings on the gilthead sea bream (Sparus aurata) in laboratory experiments. Fish were pulse-incubated for 8 hours with 3 different jellyfish densities in experimental tanks. Gill disorders were assessed through histological analyses at time intervals (0, 3, 9, 24, and 48 h, and 1, 2, 3 and 4 weeks) after the pulse exposure to jellyfish. Our results demonstrated that P. noctiluca may severely affect caged sea bream gill integrity as soon as 3 h after interaction with jellyfish tissuesPeer Reviewe

Occurrence of epibenthic dinoflagellates in relation to biotic substrates and to environmental factors in Southern Mediterranean (Bizerte Bay and Lagoon, Tunisia): An emphasis on the harmful Ostreopsis spp., Prorocentrum lima and Coolia monotis

International audienc

Gill lesions in fish exposed to <i>Pelagia noctiluca</i>.

<p>A. Healthy fish gill from the control (no jellyfish) group (0h) (100x); B-E. pathology in fish gills from the treatment groups after 8-h exposure to jellyfish: B. black arrows indicate lamellar hyperplasia on fish gill from the low jellyfish density group at 9h (400x); C. lamellar hyperplasia (1) and fusion (2) from the medium jellyfish density group after 1 week (100x); D. epitheliocystis (black arrow) and lamellar oedema (1) from the medium jellyfish density group after 3 weeks (400x); E. hyperplasia of the epithelium of the primary lamellae (1), necrosis focal of secondary lamellae (2) and circulatory disturbances (3) from the high jellyfish density group after 48h (100x).</p

External lesions on <i>Sparus aurata</i> due to <i>Pelagia noctiluca</i> jellyfish exposure.

<p>A. Fish gill from control group; B. abrasion, haemorrhage, depigmentation and increased thickness of lamellar filaments of a fish from the high jellyfish density group 24 h after exposure to jellyfish; C. wound with necrotic tissue on the flank of <i>Sparus aurata</i> fish from the medium density group 2 weeks after exposure to jellyfish.</p

Histopatholical gill damage of experimental groups over time.

<p>MLH: Mild lamellar hyperplasia; MLF: Mild lamellar fusion; MoLH: Moderate lamellar hyperplasia; MoLF: Moderate lamellar fusion; MCA: Mild cellular anomalies; MoCA: Moderate cellular anomalies; SLH: Severe lamellar hyperplasia; MCO: Mild cellular oedema; FM: Fish mortality; (NA): data not available; (---): Non significant gill damage. Colours indicate the severity of gill damage: cream colour = mild injuries; orange = medium level of injuries; violet and purple = medium-high and high level of gill damage respectively.</p

Average gill scores of treatment groups.

<p>Gill scores of control, low, medium and high <i>Pelagia noctiluca</i> jellyfish density groups before (0 h) and at different times after <i>Sparus aurata</i> exposure to jellyfish. Fish were not sampled from the highest jellyfish density group at 24 h, 3 and 4 weeks sampling points (vertical bars denote standard error).</p

Macrophyte collection sites (North of Tunisia, Southern Mediterranean Sea).

<p>Circle: Menzel Jemil station; Triangle: Menzel Bourguiba station.</p

Phytochemicals associated with <i>Ulva rigida</i>, <i>Zostera noltei</i> and <i>Cymodocea nodosa</i> species with their reported biological activity.

<p>Phytochemicals associated with <i>Ulva rigida</i>, <i>Zostera noltei</i> and <i>Cymodocea nodosa</i> species with their reported biological activity.</p