Influence of Winter Storms on the Sea Urchin Pathogen Assemblages

Abstract

In recent years, recurrent sea urchin mass mortalities in the Canary Islands have been registered. These mortality-related events have decimated 93% of the eastern Atlantic populations of the barren-forming sea urchin Diadema africanum. Two severe episodes of rough southeastern seas led to winter storms in February 2010 (Xynthia) and February 2018 (Emma) and preceded the last mass mortality event. We hypothesized that these events are related to the mass mortalities registered during the February in those years. Previous studies identified Neoparamoeba branchiphila as the causal agent of the disease, possibly acting in synergy with Vibrio alginolyticus and/or other pathogens. To determine the link between winter storms and the sea urchin pathogen community, we monitored the marine pathogen assemblage before and after the winter storm Filomena (February 2020) on Tenerife Island, on different habitats (sea water, sediment and algae) and in four species of sea urchin hosts (D. africanum, Arbacia lixula, Paracentrotus lividus and Sphaerechinus granularis). A total of six pathogens, including N. branchiphila, Vexillifera minutissima, Acanthamoeba sp., Vahlkampfia sp., V. alginolyticus and green colonies of Vibrio spp., were identified. Only small amoebas were found in sea urchins, while Vibrio species were more common in seawater, sediment and algae substrates. V. alginolyticus was occasionally detected in three sea urchins specimens, while N. branchiphila was found in the coelom of all four sea urchin studied. As previously hypothesized, a significant pathogen increment in seawater and in the sea urchin species D. africanum and P. lividus, was found after Filomena. Our results confirmed the relationship between the winter storms and marine pathogen dynamics. However, further studies are needed to demonstrate the direct relationship between these pathogen increases and the sea urchin mass mortalities.

The “Bald Disease” of the Sea Urchin Paracentrotus lividus: Pathogenicity, Molecular Identification of the Causative Agent and Therapeutic Approach

“…This cannot be considered as the proof they are the actual etiological agents, because other microorganisms could prime the process and environmental pressures could contribute to its activation [ 19 , 24 ]. In fact, when we injected coelomic fluids collected from the bodies of diseased individuals into the bodies of healthy sea urchins, these were unable to prompt an infection.…”

“…Epizootics of Strongylocentrotus droebachiensis in the NW Atlantic and NE Pacific, and P. lividus and Diadema antillarum in the eastern Atlantic, have been linked to climate changes and the overfishing of sea urchin predators, as reported by Feehan and Scheibling [ 23 ]. Very recently, Salazar-Forero et al [ 24 ] confirmed the relationship between winter storms and sea urchin marine pathogen dynamics. In fact, they monitored the marine pathogen assemblage before and after a winter storm on Tenerife Island on different habitats including sea water, sediment and algae, and in four species of sea urchin hosts, D. africanum , Arbacia lixula , P. lividus and Sphaerechinus granularis .…”

Study of histopathology on Arbacia lixula (Arbaciidae: Arbacioida) and Paracentrotus lividus (Parachinidae: Camarodonta) with bald sea urchin disease symptoms in Gran Canaria Island, Spain

“…In both cases, the infection agents were not deeply described. In addition, sea urchin diseases have been reported between 2001 and 2020 in some regions of Webbnesia: Madeira (Portugal), and Tenerife and La Palma in Canary Islands (Spain), mainly in Diadema africanum (Rodríguez, Hernández, Clemente & Coppard, 2013), but in other species as Paracentrotus lividus (Lamarck, 1816), Arbacia lixula (Linnaeus, 1758), and Sphaerechinus granularis (Lamarck, 1816) (Clemente et al, 2014;Dyková et al, 2011;Girard et al, 2011;Gizzi et al, 2020;Hernández et al, 2020;Salazar-Forero et al, 2022), and it is important to highlight that there are no reports of mass mortalities or diseases in Gran Canaria Island.…”

“…In recent times, some authors have reported the pathogenic action of different infectious agents in sea urchins, such as bacteria, protozoan, fungi, and algae, being bacteria the most common agent appearing in all diseases (Dyková et al, 2011;Gizzi et al, 2020;Grech et al, 2019;Grech et al, 2022;Hernández et al, 2020;Hewson et al, 2023;Jangoux, 1987;Salazar-Forero et al, 2022;Shaw et al, 2024;Shimizu et al, 1995;Wang et al, 2013b;Wang et al, 2023). In the case of bacteria, one of the groups most frequently described in marine habitats is that of the Vibrio genus, which increases its concentration during the temperature rise and produces blooms (Mira-Gutiérrez & García-Martos, 1998).…”

“…Several authors around the globe have reported Vibrio spp. in diseased tissues of some sea urchin's species, such as D. africanum, Strongylocentrotus intermedius (A. Agassiz, 1864), and P. lividus (Becker et al, 2008;Clemente et al, 2014;Gizzi et al, 2020;Grech et al, 2022;Salazar-Forero et al, 2022;Shimizu et al, 1995;Wang, Feng et al, 2013;Wang et al, 2023). However, there is some controversy because the same bacteria are isolated from healthy sea urchins, leading to their classification as opportunistic rather than primary pathogens.…”