KR-102962922-B1 - Method for cultivating Copepod with photoperiod-conditioned

Abstract

The present invention provides a technology that can achieve an improvement in egg production rate and early larval production rate by controlling the photoperiod during the process of culturing Eurytemora pacifica , a copepod suitable as feed for the early larval rearing of fish fry, and can present conditions for stably supplying high-quality feed in marine aquaculture of early fish fry by replacing rotifers and artemia, which have been used as existing feed organisms.

Inventors

• 최서열
• 서호영
• 이석주

Assignees

• 전남대학교 산학협력단

Dates

Publication Date

20260511

Application Date

20230518

Claims (6)

1. A method for culturing copepods comprising a photoperiod control step of exposing an adult female copepod to light (L):dark (D) conditions of a cycle of 0L:24D to 13L:11D, A method for culturing copepods, wherein the copepod is of the species * Eurytemora pacifica *.
2. delete
3. A method for culturing copepods according to claim 1, wherein the photoperiod control step is performed for 6 to 30 days.
4. A method for culturing copepods according to claim 1, wherein the photoperiod control step is performed under conditions of an illuminance of 800 to 1,500 lx.
5. A method for culturing copepods according to claim 1, wherein the photoperiod control step is performed under conditions of a water temperature of 5 to 15°C.
6. A method for culturing copepods according to claim 1, wherein the photoperiod control step is performed under conditions of salinity of 25 to 40 psu.

Description

Method for cultivating photoperiod-conditioned copepods The present invention relates to a method for culturing copepods conditioned to photoperiods, and more specifically, to a technology that can increase the production of naupliar by exposing adult female Eurytemora pacifica to specific photoperiod conditions and performing a photoperiod control step. Copepods constitute the majority of zooplankton and play an important role in transferring matter and energy to higher levels by feeding on phytoplankton, which are primary consumers. Copepod productivity is primarily influenced by water temperature, salinity, the quantity and quality of feed, stocking density, and photoperiod. Photoperiod is a crucial factor in controlling copepod egg production and population dynamics, and it is a factor that can be easily controlled in controlled environments such as aquaculture farms. In particular, among various planktonic copepods, the genus Eurytemora is considered an ideal candidate for aquaculture feed. The early larvae of small copepods are important as food for the early larvae of small-mouthed fish species such as groupers ( Epinephelus coioides ) and tropical snappers . However, despite the recognized advantages of copepods as early food for larvae, they have not reached a high level as feed organisms in the aquaculture industry due to issues of practicality and cost-efficiency, as there are limitations in that productivity is extremely low due to the difficulty of cultivation. Therefore, in order to secure the naupliar of * Eurytemora pacifica *, which is useful as an initial food source for fish larvae, it is necessary to evaluate the influence of photoperiod on egg production and hatching success and to develop methods to improve productivity. In order to improve the productivity of copepods and enable their use as food for actual cultured organisms, it is necessary to study photoperiod conditions that can be easily controlled, especially in controlled environments such as aquaculture farms. Figure 1 is a graph showing the average egg clutch size of adult female Eurytemora pacifica exposed to different photoperiod conditions according to one embodiment of the present invention. FIG. 2a is a graph showing the average hatching rate after exposing egg sacs obtained from a stock culture to different photoperiod conditions according to one embodiment of the present invention. FIG. 2b is a graph showing the average hatching rate of cysts obtained from adult female Eurytemora pacifica exposed to different photoperiod conditions according to one embodiment of the present invention. Figure 3 is a graph of the production rate of naupliar from adult female Eurytemora pacifica exposed to different photoperiod conditions according to one embodiment of the present invention. The present invention will be explained in more detail below through the following examples. However, these examples are merely illustrative of the invention, and the scope of the invention is not limited by these examples. Throughout this specification, "%" used to indicate the concentration of a particular substance is (weight/weight)% for solid/solid, (weight/volume)% for solid/liquid, and (volume/volume)% for liquid/liquid, unless otherwise noted. Tukey multiple comparison analysis was performed on the data using SPSS program version 20.0 (SPSS Inc., Chicago, IL, USA), and the significance level was set at p < 0.05. Test Example 1: Design and Preparation of Experiment 1-1. Preparation of Yuritemora Pacifica To establish a stock culture of * Eurytemora pacifica *, repeated vertical sampling was performed on December 7, 2020, in the waters of Gamak Bay (34° 43′ 57″ N, 127° 40′ 57″ E), South Korea, using a conical net (mesh size: 200 μm, inlet diameter: 30 cm). Adult E. pacifica specimens were transferred within 1 hour to a 10 L plastic carboy filled with field-filtered seawater (GF/C Whatman filter, 0.45 μm) and then placed in an incubator for cultivation. During cultivation, water temperature and salinity were maintained at 10±1℃ and 32±1 psu, respectively, under a photoperiod (winter) of 10L:14D (light:dark) with an illuminance of 1,200 lx. Additionally, each carboy was filtered to allow for gentle air circulation. During cultivation, approximately 80% of the filtered seawater in the carboys was replaced with fresh seawater filtered through 40-μm every three days. E. pacifica were fed a mixture of Tetraselmis suecica and Isochrysis galbana (40,000 cells/mL of both). 1-2. Preparation of Microalgae The microalgae T. suecica (diameter 8 μm) and I. galbana (diameter 4.5 μm) are important nutrient sources commonly used in the aquaculture industry; both were initially used as feed for rotifers, copepods, or Artemia in hatcheries, serving directly as food for shellfish and indirectly as food for fish larvae. In this study , T. suecica and I. galbana were cultured in f/2 medium within 2-L roller bottles with vigorously circulating 0.2 μm filtered air in a