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Leptothecata: families Kirchenpaueriidae and Halopterididae. a, Ventromma halecioides, part of hydrocaulus, with two hydrocladia, Isla Santa Cruz, Puerto Ayora, main passenger dock, JJM Hyd. 7, scale equals 0.20 mm. b, Ventromma halecioides, part of hydrocaulus, with a hydrocladium, nematothecae, and a hydrotheca, Isla Santa Cruz, Puerto Ayora, main passenger dock, JJM Hyd. 7, scale equals 0.1 mm. c, Halopteris alternata, part of hydrocaulus, with a hydrocladium, nematothecae, and three hydrothecae, Isla Santa Cruz, Puerto Ayora, main passenger dock, JJM Hyd. 1, scale equals 0.2 mm. d, Halopteris alternata, part of a hydrocladium, with nematothecae and a hydrotheca, Isla Santa Cruz, Puerto Ayora, main passenger dock, JJM Hyd. 1, scale equals 0.1 mm.
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An account is given of hydroids collected in 2015 and 2016 from port and harbor fouling communities in the Galápagos Islands. Also included is the hydroid of Ectopleura media, discovered on the wreck of the tanker Jessica near Isla San Cristóbal in 2001. Among 20 species reported herein were six anthoathecates and 14 leptothecates. Most common in t...
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Although Porpita porpita is native to tropical and sub-tropical waters and widely occurred in the Atlantic and Indo-Pacific oceans and Mediterranean Sea, its occurrence has not been reported from Red Sea. Three specimens of P. porpita were collected in the middle littoral zone of the Egyptian Red Sea coast off Hurghada in December 2014. Specimens w...
Citations
The hydroids of Cocos Island (Isla del Coco), Costa Rica, have received scant attention and are poorly known. Only 11 species have been reported from there previously, with five of them being stylasterids. Hydroids examined here were collected during 2019 in a search for invasive species, as part of a fouling survey. Fourteen species – three anthoathecates and 11 leptothecates – were identified in the collection. All represent new records for Cocos Island, elevating its number of reported species to 25. The most abundant species in the collection were Clytia obliqua (Clarke, 1907) and Sertularella affinicostata Calder and Faucci, 2021, found in 11 of 42 samples (26%), and Tridentata borneensis Billard, 1925a, present in nine (21%) of them. Nematocysts of Corydendrium flabellatum Fraser, 1938a and Eudendrium cf. certicaule Fraser, 1938a are newly identified, measured and illustrated. Three species (Clytia brevithecata (Thornely, 1900), Halopteris alternata (Nutting, 1900) and Macrorhynchia philippina Kirchenpauer, 1872), are introduced, with the rest assigned to a native or cryptogenic status.
1. Marine traffic is the main vector for marine non-indigenous species (NIS), that may hitchhike in ballast water tanks or attached to vessel hulls. Understanding marine traffic dynamics and estimating the associated risk of NIS dispersal reveals points of leverage for preventive NIS management. This study presents a method to quantify the risk of ship hull fouling-mediated NIS dispersal, and identifies main dispersal hubs in marine traffic networks. We use the Galapagos Marine Reserve (GMR) as a case study to test the applicability of this method.
2. Ship position data derived from the automatic identification system (AIS) served as a basis for a network consisting of nodes (moorings and anchorages) and edges (ship routes). Wetted surface areas (WSA) describe the parts of vessel hulls submerged by water and were used to parameterize dispersal risks of individual vessels. We combined the constructed network with a numeric dispersal model and sequentially removed network elements to test their effectiveness on decreasing the overall dispersal capacity.
3. Marine traffic hotspots, such as ports and popular marine visitor sites represented the main dispersal hubs and incoming edges into the GMR crucial links for the overall dispersal capacity. The removal of passenger vessels had the strongest effect on the overall dispersal capacity, reducing it to 1%.
4. Based on our findings, we suggest management recommendations to curb the spread of marine NIS in the GMR, including the implementations of (i) vessel hull controls at main dispersal hubs (ports); (ii) species monitoring programs at popular marine visitor sites; and (iii) hull husbandry regulations for passenger vessels.
5. Synthesis and Application: In an increasingly connected world, the development of risk assessments for marine NIS dispersal is a crucial step towards the sustainable use and protection of marine ecosystems in Galapagos and other places. The presented methodology is solely based on the pathway component and thus applicable to any place with available ship position data. Therefore, it may provide useful baseline information for preventive measurements especially in places where ecological data about NIS is scarce.
This report is based on a small collection of hydroids from the Hawaiian Islands, in the central Pacific Ocean. Most of the examined material was obtained by staff of the Bernice Pauahi Bishop Museum, Honolulu, during surveys for nonindigenous marine species in shallow, sheltered, inshore or nearshore waters, and especially in harbours, bays, and lagoons. In all, 34 species of leptothecate hydroids, assigned to 14 families and 20 genera, were identified and are discussed. One of them, based on a single infertile colony with a damaged hydrotheca, was identified provisionally only to the rank of suborder. Given the limited geographic and bathymetric focus of the surveys, only four of the species, Clytia thornelyi, Halecium sibogae, Macrorhynchia balei, and M. hawaiensis, were collected at depths greater than 25 m. Seven species, Cirrholovenia tetranema Kramp, 1959, Orthopyxis crenata (Hartlaub, 1901), Clytia elongata Marktanner-Turneretscher, 1890, C. paulensis (Vanhöffen, 1910), Tridentata maldivensis (Borradaile, 1905), Monotheca flexuosa (Bale, 1894), and a hydroid identified only as Eirenida (undetermined), are recorded from Hawaii for the first time. Three others, Lytocarpia nigra (Nutting, 1905) Macrorhynchia balei (Nutting, 1905), and M. hawaiensis (Nutting, 1905), have their type localities in Hawaii, with the last of these being known to date only from the Hawaiian archipelago. Most of the species are well-known from shallow water areas across the tropical and subtropical Indo-Pacific region, and over half of them have been reported as well from warm waters in the Atlantic Ocean. Their existence in the remote islands of Hawaii is attributed to long-range dispersal by both natural and human-mediated means, including shipping.
Only a few studies have been devoted to the species identification and the distribution of marine hydroids Ectopleura in Japanese coastal waters, despite the scale of fouling problems that they pose. We collected polyps from the coast of the western and northern parts of Japan, and analyzed their morphological characters and mitochondrial COI genes. As a result, while polyps settled on fishing nets along the coast of Hokkaido were Ectopleura radiata, E. crocea were spotted along the Pacific coast of Honshu. Dense polyp colonies on pontoons along the coasts of Seto Inland Sea in mid-to-late winter were also identified for the first time as E. radiata. In addition, phylogenetic analysis has identified Ectopleura sp. JRH-2014 spotted in the China Seas as E. radiata. Regarding actinulae of E. radiata, we devised a new assay composed of hexagonal columnar cell using test slide glasses, and a magnetic stirrer, and examined the settlement inhibitory effects of the silicone-based coatings. The results found that actinulae proved very sensitive to copper pyrithione contained in anti-fouling agents and the age of coatings.
We provide preliminary insights into the global phylogeographic and evolutionary patterns across species of the hydrozoan superfamily Plumularioidea (Cnidaria: Hydrozoa). We analyzed 1,114 16S sequences of 198 putative species of Plumularioidea collected worldwide. We investigated genetic connections and divergence in relation to present‐day and ancient biogeographic barriers, climate changes and oceanic circulation. Geographical distributions of most species are generally more constrained than previously assumed. Some species able to raft are dispersed widely. Human‐mediated dispersal explains some wide geographical ranges. Trans‐Atlantic genetic connections are presently unlikely for most of the tropical‐temperate species, but were probably more frequent until the Miocene–Pliocene transition, before restriction of the Tethys Sea and the Central American Seaway. Trans‐Atlantic colonizations were predominantly directed westwards through (sub)tropical waters. The Azores were colonized multiple times and through different routes, mainly from the east Atlantic, at least since the Pliocene. Extant geminate clades separated by the Isthmus of Panama have predominantly Atlantic origin. Various ancient colonizations mainly directed from the Indian Ocean to the Atlantic occurred through the Tethys Sea and around South Africa in periods of lower intensity of the Benguela upwelling. Thermal tolerance, population sizes, dispersal strategies, oceanic currents, substrate preference, and land barriers are important factors for dispersal and speciation of marine hydroids.
