Codium fragile sp. fragile Species Gallery (0020)

Scientific Name:

Codium fragile sp. fragile

Κοινό όνομα:

Green sea fingers

Ταξινομική Ομάδα:

Φύκη

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Πληροφορίες

Διαγνωστικά χαρακτηριστικά

A large, dark green alga consisting of one to several erect fronds, 15–20 cm high, with abundant cylindrical branches in a dichotomous or fastigiated pattern, and attached to the substrate by a broad spongy basal disc. The cylindrical branches are 0.3–1 cm in diameter. Shape and structure may vary depending on the environmental conditions.

The species can only be distinguished from several other similar varieties or subspecies under a binocular microscope by the shape of the microscopic flask-shaped outer structures (utricles). Codium fragile subsp. fragile has a hairy surface and the utricles at the tips of the branches form regular cylinders with a sharp terminal point.

Αναγνώριση / Ενδιαίτημα

Όπως και άλλα είδη Codium , C. fragile subsp. Το είδος είναι μαλακό και σαν σφουγγάρι στην αφή. Ανέχεται μεγάλες διακυμάνσεις της αλατότητας και θερμοκρασίας, επιτρέποντάς του να αποικίσει ένα ευρύ φάσμα χώρων. Φαίνεται να ευδοκιμεί στην διαπαλλοιριακή και στα ρηχά, σε βραχώδεις πυθμένες και σε προστατευμένους οικοτόπους όπως λιμάνια και όρμους.

Αναπαραγωγή

Its success as a rapid colonizer may be attributed to its range of propagation techniques. It can reproduce either sexually or by releasing small propagules in the water column, which are dispersed locally. It also reproduces vegetatively by fragmentation of the thallus, forming new plants that are dispersed by currents and re-attach elsewhere, or from basal holdfasts that remain after fragmentation. The plant is perennial, proliferating each spring from a persistent basal portion.

Περιγραφή παρόμοιου είδους

Due to its morphology, C. fragile subsp. fragile could be mistaken for two other Codium species: the native C. vermilara and C. decorticatum, and only microscopic examination of the utricles, which are only cylindrical in C. fragile, can reveal the difference.

In C. vermilara, branches frequently bear simple or forked proliferations and the tips of the utricles are rounded with numerous hairs. C. decorticatum is a species with fewer branches that can reach a height of 1 metre. Its utricles are regular cylinders, dilated at the tip but without a sharp point.

Codium fragile sp. fragile Similar Species (0010) EL — **C. fragile, C. vermilara, C. decorticatum**

Ιστορία και τρόπος εισαγωγής

Native to the North Pacific Ocean and Japan, this subspecies is nowadays widespread, having been introduced on shellfish for aquaculture, on recreational boats and on ship hulls. Secondary introductions are probably from aquaculture farms, vessels and fouling on fishing nets.

Οικολογικές επιπτώσεις

The closely packed frond structure of C. fragile traps sediments, eventually changing the nature of the substrate. It is a ‘low-lying’ alga, making it difficult for some large invertebrates and fish to find refuge or food between the bushy parts of the alga and the seabed. It also has a profound effect on native communities, outcompeting other algae and invertebrates.

Οικονομικές επιπτώσεις

C. fragile also has serious economic implications for aquaculture industries, as it has been found to overgrow and smother oyster beds.

Διαχειριστικά μέτρα

Prevention: Preventing the spread of C. fragile through quarantine measures such as compulsory isolation protocols for shellfish to be cultured in new regions (the main vector of introduction) and public education are some of the few ways to ensure it does not spread further.

Eradication: There are a few options available to manage C. fragile, although with some limitations. Chemical herbicides are not a viable control option as they have adverse effects on native communities. Mechanical removal techniques such as trawling, cutting, and suctioning have been tried in different areas. They help to reduce the density of C. fragile temporarily, but these methods are generally expensive and the populations quickly rebound to normal densities. Manual removal could be an alternative, but great care is needed as the algae readily reproduce from fragments.

Επιπλέον πληροφορίες

http://www.europe-aliens.org/pdf/Codium_fragile.pdf

Bridgwood, S., 2010. Codium fragile ssp. fragile (Suringar) Hariot summary document. 2010. Fisheries Research Report No. 202. Department of Fisheries, Western Australia. 12 p.

C. Rodríguez-Prieto, et al., in press. Guía de las macroalgas y fanerógamas marinas del Mediterráneo Occidental. Omega, Barcelona.

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