Method of stopping larva from swimming or crawling

Abstract

The present invention provides methods of stopping a larva of a sessile invertebrate in a settlement stage from swimming or crawling in water, by means of irradiating violet light having a wavelength range of 400 to 550 nm to the larva in the settlement stage of the sessile invertebrate.

Claims

1. A method of stopping a larva of Pteriomorphia in a settlement stage from swimming or crawling in water, comprising the step of: irradiating light in a wavelength range including 400 to 550 nm to the larva in the settlement stage, wherein the light consists of a part of the visible spectrum and does not comprise the entire visible spectrum and wherein the light is not a laser beam.

2. A method of stopping a larva of Pteriomorphia in a settlement stage from swimming or crawling in water, comprising the step of: irradiating light in a wavelength range including 400 to 440 nm to the larva in the settlement stage, wherein the light consists of a part of the visible spectrum and does not comprise the entire visible spectrum and wherein the light is not a laser beam.

3. The method according to claim 1 or 2, wherein the water is seawater.

4. The method according to claim 3, wherein the sessile invertebrate is a mussel or an oyster.

5. The method according to claim 4, wherein the larva in the settlement stage is a pediveliger or a plantigrade of Mytilus galloprovincialis or Perna viridis.

6. The method according to claim 3, wherein the larva in the settlement stage is a pediveliger or a plantigrade of Mytilus galloprovincialis or Perna viridis.

7. The method according to claim 1 or 2, wherein the sessile invertebrate is a mussel or an oyster.

8. The method according to claim 7, wherein the larva in the settlement stage is a pediveliger or a plantigrade of Mytilus galloprovincialis or Perna viridis.

9. The method according to claim 1 or 2, wherein the larva in the settlement stage is a pediveliger or a plantigrade of Mytilus galloprovincialis or Perna viridis.

10. The method according to claim 1 or 2, wherein the intensity of the irradiated light is 200 to 2,000 W/m.sup.2.

Description

EXAMPLE

(1) In this example, a pediveliger larva of Mytilus galloprovincialis was placed in each of Petri dishes containing 4 mL of seawater (depth of water: 2 mm) that had filtered through a filter with a mesh opening of 3 μm. Light having a wavelength range of 330 to 385 nm (U radiation), 400 to 440 nm (BV radiation), 460 to 490 nm (GFP radiation), or 510 to 550 nm (G radiation) was irradiated to the larva using an epifluorescence unit for a microscope (OLYMPUS SZX-RFL3) under the observation with a stereomicroscope. The irradiation was continued until the larva closed its shell. The irradiation time before the shell closure and the duration of time while the larva kept its shell closed after the irradiation was stopped were measured. If the larva did not close its shell after 10 minutes, the irradiation was stopped at that time. A plurality of the tests was performed for each range of the wavelength using seven larvae. The conditions and results of the tests are given in Table 1 below.

(2) TABLE-US-00001 TABLE 1 Seven pediveligers of Mytilus galloprovincialis Wavelength Average Average shell range Intensity irradiation closure Irradiation (nm) W/m.sup.2 time (sec.) time (sec.) U 330-385 56.2 67 87 BV 400-440 1013.0 22 120 GFP 460-490 418.2 Not closed — G 510-550 1875.7 Not closed — Not closed: the larva did not close its shell after the lapse of 10 minutes.

(3) Similar tests were performed on pediveligers and plantigrades of Perna viridis and the conditions and results of the tests are given in Tables 2 and 3.

(4) TABLE-US-00002 TABLE 2 Eleven pediveligers of Perna viridis Wavelength Average Average shell range Intensity irradiation closure Irradiation (nm) W/m.sup.2 time (sec.) time (sec.) U 330-385 56.2 17 174 BV 400-440 1013.0 10 304 GFP 460-490 418.2 Not closed — G 510-550 1875.7 Not closed —

(5) TABLE-US-00003 TABLE 3 Six plantigrades of Perna viridis Wavelength Average Average shell range Intensity irradiation closure Irradiation (nm) W/m.sup.2 time (sec.) time (sec.) U 330-385 56.2 16 61 BV 400-440 1013.0 5 134 GFP 460-490 418.2 48 53 G 510-550 1875.7 26 67

(6) The pediveligers with U and BV irradiations and the plantigraedes with any one of the irradiation ranges tested closed their shells and stopped swimming or crawling during the irradiation of the light. The larvae kept closing their shells for a certain duration of time after the irradiation was stopped. Considering that the violet light has a higher transmittance in the seawater than the ultraviolet light, it can be understood that the BV irradiation for the pediveligers and the BV, GFP and G irradiations for the plantigrades are particularly effective in order to stop the larvae in the settlement stage from swimming or crawling in water.

INDUSTRIAL APPLICABILITY

(7) The present invention makes it possible to provide methods of stopping larvae of sessile invertebrates in the settlement stage from swimming or crawling in water.