FEEDING
BY LARVAE OF THE MUSSEL MYTILUS GALLOPROVINCIALIS ON
RED-TIDE DINOFLAGELLATES
H.J. Jeong, J.Y. Song, C.H. Lee, S.T. Kim-2004
Journal of Shellfish Research, 23(1): 185-195
Abstract:
To investigate feeding by the larvae of the
mussel Mytilus galloprovincialis on red-tide dinoflagellates, we
measured grazing rates of M. galloprovincialis larvae as a function
of larval age and prey concentration when feeding on several species of the
red-tide dinoflagellates Alevandrium affine, Coccodinium polykrikoides.
Lingulodiniun polyedrum, Prorocentrum minimum, Prorocentrum micans, and
Scrippsie/la trochoidea, as well as the flagellate Isochrvsis
galhana as a control species. The larvae were able to ingest all
dinoflagellates offered in the current study; however, first feeding of the
larvae on each species of the dinoflagellates occurred 9-13 days after
fertilization, whereas that for I. galbana occurred after 5 days.
Ingestion rates of the larvae on unialgal diets of the dinoflagellates and I.
galbana increased with increasing larval age up to 17-21 days, but were
saturated or showed a continuous increase thereafter. Ingestion rates of
25-day-old larvae feeding on unialgal diets of the dinoflagellates increased
rapidly with increasing prey concentration up to 1000-2200 ng C mL-1,
but were saturated at higher prey concentrations. The harmful alga C. polykrikoides, which has been responsible for great losses in
the aquaculture industry, was the optimal prey. Maximum ingestion and
clearance rates of the larvae on these dinoflagellates were 14-69 ng C
predator-1 day-1 and 1.5-11.4 p.L predator-1
h-1, respectively. M. galloprovincialis larvae, one
component of microzooplankters, exhibited higher maximum ingestion and
clearance rates than previously reported for other mierozooplankters, such
as Fragilidium cf. mexicanum (mixotrophic dinoflagellate). Protoperidinium
cf. divergens, Polykrikos kofhidii (heterotrophic
dinoflagellates), or Tiarina.fusus (small ciliate), but
lower rates than Strombidinopsis sp. and Favella sp. (large
ciliates). The results of the current study suggest that dinoflagellates
sometimes can be primary prey for the Mytilus larvae, and the grazers
compete with other microzooplankters for dinoflagellate prey. Also, red-tide
dinoflagellates can be used for culturing the Mytilus larvae as prey
in the aquaculture industry.
(School of
Earth and
Environmental Science, College of Natural Sciences, Seoul National
University, Seoul 151-74, Republic of Korea, e-mail: hjjeong@snu.ac.kr)