M 21
VAKILY, J.M., TAUYCHAROEN, S and J. NUGRANAD
Analysis of length and weight characteristics of
green mussel, Perna viridis, from Thailand.
1988 10 pp
Asian Fisheries Science 1(1988): 165–174
The following parameters were measured (female and males separately) in 1,760 individuals of the green mussel, Perna viridis: size (lenght, height), weight (total, fresh + shell, flesh wet, flesh dry). Size/weight relationships were determined as well as the relationships within various weight units. The analysis suggests that the weight unit ‘flesh + shell’ should be used as a standard unit for total weight. With this unit taken as weight, the exponent ‘b’ of the size/weight relationship varies between 2.55 and 2.87, depending whether ‘length’ or ‘height’ is used as dimension unit. The sex in the sample was 44% male to 56% female. Sexual growth dimorphism was not observed.
M 22
YAMADA, S.B. and E.E. PETERS
Harvest management and the growth and condition of
submarket-size sea mussel, Mytilus californianus.
1988 6 pp
Aquaculture, 74, 293–299
Wild population of the sea mussel, Mytilus californianus, are being harvested commercially from open permit areas on the Oregon coast. This study tests the hypothesis that a controlled harvest increased the growth rate and condition index of the remaining submarket-size mussels (less than 4 cm in length) by reducing competition. Six harvest plots (50 cm × 50 cm) were created in dense mussel beds at various seasons by removing the surface layers of mussels and leaving at least one layer on the rock substrate. Submarket-size mussels, 2–4 cm in length, were individually marked and measured. Half of the marked mussels were wedged in between the remaining mussels of the harvest plot, while the other half were placed into adjacent undisturbed plots. Plots were harvested after 3–8 months and the growth and condition of the marked mussels determined. Mussels grew significantly more in the harvested plots (0.6–1.7 mm per month) than in undisturbed plots (0.4–1.4 mm per month). Condition index (weight of dry meat, g×100/shell volume, ml) was also significantly greater in harvested (10–15) than in control (9–20). The implications of these findings for the management of M. californianus beds are discussed.
