| Budget Amount *help |
¥3,800,000 (Direct Cost: ¥3,800,000)
Fiscal Year 2004: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2003: ¥2,900,000 (Direct Cost: ¥2,900,000)
|
|---|
| Research Abstract |
During 2003-04,a total of 171 net sampling were made waters off Hyuganada, east Kyushu. These sampling ware designed to collect anguilloid eggs. Samplings were made with 1.6 m diameter ring net constructed with 0.5 mm mesh using four layers towing methods (0,5,15,30m depth). Sampling effort was most intensive during summer, however, monthly samples were taken around year. A total 1,215 eggs comprising 19 species were taken. Families represented include the Muraenidae, Ophichthidae, Congridae, Muraenesocidae, and Nettastomatidae from the morphological characteristics, for example, egg diameter, oil globule, pigmentation and number of myomeres of newly hatched larvae. To determine species level identification, mitochondrial DNA(16SrRNA) sequences of those eggs were compared those of adults. Twenty five species were recoginaized from those 19 types eggs. Most species showed highly seasonal patterns of abundance during summer. Based on the present study, following major characters of eggs are revealed ; Muraenidae : absent or few oil globules,2.30-5.50 mm diameter ; Ophichthidae : absent or many oil globules, 1.62-4.40 mm diameter ; Nettastomatidae : absent or two oil globules, 1.98-3.24 mm diameter, Muraenesocidae : many oil gbobules,2.00-2.46 mm diameter.
|
