Mussel Aquaculture

choi

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Beth Daley, Farm-raised mussels pass first local test. Boston Globe, Sept. 6, 2010.
http://www.boston.com/news/local/massachusetts/articles/2010/09/06/farm_raised_mussels_pass_first_local_test/

My comment: There is no need to read it. The report says that US is trying to grow mussels domestically, in aquaculture. I was surprised to learn that mussels in the marets rarely grow in sand.

(A) Harvest of wild mussels has declined steadily in United States. Most mussels consumed in US are imported, mainly from Canada but as far as from New Zealand.

"US production--1,545 mt [metric tons] (2005) vs US imports 19,000 mt"[1]

(B) The foreign mussels are from aquaculture.

"20 months to market in PEI vs. 10-12 months in So. New England"[1]

[1] Scott Lindell et al, Progress on New Strategies for Mussel Farming in Southern New England; Pilot Commercial-Scale Offshore Farms Launched. Marine Biological Laboratory, Woods Hole, Massachusetts, undated.

(C)
(a) Please take a look at the illustartion in

Submerged Coastal-Offshore Mussel Aquaculture System (SCOMAS). Marine Biological Laboratory, undated.
http://www.whoi.edu/science/MPC/dept/research/Mussel%20Aquaculture/scomas_research.html

Note:
(i) A single horizontal line bracketed on both ends by (yellow cicles) corner buoys is the "longline."
(ii) Hanging down from the longline are "growout ropes"--in the right-hand side of the illustration--on which mussels mature ("growout" because they extends from the longline).
(iii) In the left-hand side of the illustration are "socking loops" with "weak links at bottom of each socking loop." The socks and weak links are biodegradable in a few days, and will become growout ropes.

(b) There is no need to read the text of this link, except the following quotes:

"The longline operates in a submerged mode to avoid the destructive effects of surface waves.

"Losses due to mortality, predation, and user conflicts should be minimal because the mussels are isolated from both the surface (where they are vulnerable to ducks) and the seafloor (where they can be attacked by starfish).

(D) A web page about mussel aquaculture. from

Department of Fishieries, Aquaculture and Rural Development, Prince Edward Island, Canada.
http://www.gov.pe.ca/fard/index.php3?number=78245&lang=E

* The "Hisotry" button in the left column states that aquaculture in PEI has a short history, starting around 1980.

(a) The above, (D) has a section "Seed Collection" which talks about mussel larvae/spats/seeds. It does not explain why procure seeds from the wild, instaed of producing them in hatecheries.

Here is the answer:

"Most mussel culture depends on the use of natural spat because of the generally abundant supply. However, hatchery technology is available. Mussels are characterized by high fecundity and a mobile free living larval phase, which have facilitated its widespread distribution."
Food and Agriculture Organization of United Nations.

* spat (n; origin unknown): "a young bivalve (as an oyster)"  www.m-w.com

(b) In aquaculture, spats will seed themselves by attaching to “collector ropes."
(c) Paragraph 6 in the section Seed Collection:

"The seed is manually stripped from each collector and transported to shore where specialized grading equipment cleans and sorts seed mussels into three or four sizes depending on the type of equipment used, and preference of use by individual growers.

This is
(i) because spats seeded on one collector rope are of different ages and sizes;
(ii) because mussels of different sizes on the growout ropes causes the small ones to fall off;
(iii) because mussels of simlar maturity should reach market together.

(E) In mussel aquaculture:

"The mussels will be grown on ropes suspended above the seabed, ensuring that they are free of grit, they said. Situated offshore, the farm will be well flushed with plankton-rich ocean water, so the mussels will require no artificial feeds, fertilizers or medicines.


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