Visit Our Diving Center
View our Accommodation
  • Diving
    • Diving Courses
    • Freediving
    • Accompanied Diving
    • Unaccompanied Diving
    • Diving Pricelist
  • Accommodation
  • Special Offers
  • Our Services
  • Dive Sites
  • About Gozo
    • Blog
  • About Us
  • Contact Us
Online Shop Dive Checkin
  • EN
    • FR
    • DE
    • IT
    • PL
  • Diving
    • Diving Courses
    • Freediving
    • Accompanied Diving
    • Unaccompanied Diving
    • Diving Pricelist
  • Accommodation
  • Special Offers
  • Our Services
  • Dive Sites
  • About Gozo
    • Blog
  • About Us
  • Contact Us
13. 08. 201913. 08. 2019

Pinna nobilis (Fan Mussel)

Home » Blog » Pinna nobilis (Fan Mussel)

Pinna nobilis, the Fan Mussel (a.k.a. Noble Pen Shell or Nakkra in Maltese), is a large species of Mediterranean clam, a marine bivalve mollusc in the family Pinnidae, the pen shells.

The Noble Pen Shell is an emblematic endemic species to the Mediterranean Sea, where it lives offshore at depths ranging between 0.5 and 60 metres.  It could be found buried beneath soft-sediment areas (fine sand, mud, often anoxic).

The genus Pinna belongs to the family Pinnidae, order Pteriida, class Bivalvia, phylum Mollusca and kingdom Animalia.

The bivalve shell is usually 30 to 50 cm long, but can reach a height of 120 cm.  Its shape differs depending on the region it inhabits.  Like all pen shells, it is relatively fragile to pollution and shell damage.  It attaches itself to rocks using a strong byssus composed of many silk-like threads which used to be made into cloth.  The animal secretes these fibres from its byssus gland; they consist of keratin and other proteins and may be as long as 6 cm. The inside of the shell is lined with brilliant mother-of-pearl.

In fact, the Fan Mussel is the origin of sea silk, which was made from the byssus of the animal.  Thus its other Maltese common name Nakkra tal-Harir, literally meaning Silk Fan Mussel.

As with other members of its genus, Pinna nobilis hosts symbiotic shrimp which live inside its shell.  It is believed that when it sees a threat, the shrimp warns the host, perhaps by retracting its claws or even by pinching.  The clam then closes shut. It has been demonstrated that the shrimp has a similar filter-feeding diet to its host and the relationship is likely mutualistic.

In recent years, Pinna nobilis has become threatened with extinction, due in part to fishing, incidental killing by trawling and anchoring, and the decline in seagrass fields; pollution kills eggs, larvae, and adult mussels.  The Noble Pen Shell has been listed as an endangered species in the Mediterranean Sea.  The European Council Habitats Directive 92/43/EEC, on conservation of natural habitats and the wild fauna and flora, proclaims that Pinna nobilis is strictly protected (by the Annex IV of EEC, 1992) – all forms of deliberate capture or killing of fan mussel specimens are prohibited by law.

Unfortunately, in the past two years a mass mortality event of the noble pen shell was detected in the western Mediterranean Sea.  The cause is very likely to be a recently identified parasite.

Dead molluscs are recognised as they are found on the bottom, open and empty, though in some cases they can still be anchored to the bottom. Unhealthy individuals affected by the parasite, but still living, close their valve very slowly and show a lack of response to stimuli.

Thus, the Physical Oceanography Research Group – University of Malta have launched a very important survey on Pinna nobilis.  To better understand the mass mortality event and devise an action plan, YOUR HELP IS NEEDED.  So please fill the quick online questionnaire: www.tinyurl.com/AMArePinnaNobilis.

The photo of this Fan Mussel was taken at a depth of 32 metres at Ras il-Ħobż on Gozo’s south coast.

Photo taken by Brian Azzopardi

Related posts

Atlantis Boot 2023
22. 12. 202212. 01. 2023

Atlantis Gozo at Boot Dusseldorf 2023

Boot Dusseldorf 2023 Hall 12/A31.8 Once again, Atlantis Gozo will participate with our stand at Boot Dusseldorf starting on 21...

Read More
Merry Christmas
16. 12. 2021

Merry Christmas & A Happy New Year 2022

Merry Christmas & A Happy New Year 2022 Wishing you all the best ! Happy Holidays from the Atlantis Gozo...

Read More
Rebreather Corner - satisfied guests
25. 07. 2021

Latest News July 2021 – Satisfied Guests

Coming across satisfied guests may not be that difficult after all.  Being thanked or rewarded for your efforts is really...

Read More

Reviews

Tolles Center für Sport- Tec und Rebreather Taucher. Bestens zu empfehlen 😃, immer wieder gerne hier 👍.
Manfred Kleemann
Manfred Kleemann
2022-05-23T05:51:17+0000
Our club goes out to Malta/Gozo every year and Atlantis was by far the best centre we have dealt with. The communication building up to the trip was great. So helpful. Our club has a mixed range of diver levels and Atlantis made sure that all our levels was covered. On arrival the welcome was very warming. They couldn’t have been more helpful. Once the admin and kit issue was done we was on our way. The end I’ve every day the team was on hand to assist us making sure we was all prepared for the following day. Nitrox, stages, fills and so on. The end of our trip the staff even came to the apartment to say farewell and seen us off. One of our club members left their regs by mistake but the team contacted us and meet us at the ferry port to return them. Thank you so much!!! We will be returning next year.
Alex Lucas
Alex Lucas
2022-04-21T07:36:58+0000
Highly recommended dive centre! We got all needed services in very friendly atmosphere. Thank you!!
Gedimas Usack
Gedimas Usack
2021-11-27T20:24:01+0000
I did a package deal of 10 dives with Atlantis and was extremely impressed from the get go. The center was very well equipped and maintained and the staff were awesome, totally committed to making sure everyone was welcomed and having fun whilst keeping a high level of professionalism. The guides (Denis, Georgia, Apollo, George) were very knowledgeable and friendly. I highly recommend Atlantis to anyone looking for a solid and trustworthy center with fair prices. P.s. Go in November, its way less busy and the vis is still good!
Jakob Wayne Víkingur Robertson
Jakob Wayne Víkingur Robertson
2021-11-18T01:22:10+0000
awesome place awesome people!
Richard Binks
Richard Binks
2021-10-20T05:07:13+0000
‹
›

Newsletter

Subscribe to our newsletter to get the latest news and special offers from the Atlantis Gozo Diving team! By doing so you agree to our Privacy Policy

Mailchimp
Sending
  • About Atlantis
    • Careers
    • Affiliates
  • Diving
    • Diving Courses
    • Diving Pricelist
    • PADI Courses
    • CMAS & VDST Courses
    • BSAC Courses
    • Speciality Courses
    • Accompanied Diving
    • Unaccompanied Diving
    • Technical Diving
    • Diving Equipment Rental
    • Freediving
  • Dive Sites
  • Holiday Services
    • Accommodation
    • Airport Transfers
    • Car Hire
    • Tours
  • Special Offers
  • Gozo
  • Gallery
    • Photo Credits
  • Contact Us

Copyright © 2023 Atlantis Diving Center. All rights reserved.
Privacy Policy | Terms & Conditions | Refund Policy

Website designed & developed by