Premium
Lunar synchronization of spawning in sea bass, Lates calcarifer (Bloch): effect of luteinizing hormone‐releasing hormone analogue (LHRHa) treatment
Author(s) -
Garcia L. Ma. B.
Publication year - 1992
Publication title -
journal of fish biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 115
eISSN - 1095-8649
pISSN - 0022-1112
DOI - 10.1111/j.1095-8649.1992.tb02583.x
Subject(s) - spawn (biology) , biology , lates , sea bass , full moon , fishery , hormone , luteinizing hormone , zoology , medicine , endocrinology , fish <actinopterygii> , ecology
Based on egg collection records, spontaneous spawning activity of sea bass, Lates calcarifer (Bloch), reared in floating net cages followed a semilunar cycle. The peak of multiple spawnings coincided with declining spring tides of quarter moon periods. Maximum diameter of intra‐ovarian, ripe oocytes (0.51–0.55 mm) occurred in synchrony with the quarter moon periods. Smaller oocytes (0.44–0.47 mm) were sampled during the new and full moon periods. Two structural analogues of luteinizing hormone‐releasing hormone (LHRHa) (des‐Gly 10 , d ‐Ala 6 ‐LHRH ethylamide and d ‐Ala 6 , Pro 9 ‐Nethylamide‐LHRH), in pelleted or dissolved form, induced mature female sea bass with a mean egg diameter of at least 0.40 mm to spawn at any day during the lunar cycle. The onset of spontaneous and LHRHa‐induced spawnings occurred during low tides in the evening until dawn (from 19.00 to 05.00 hours). These results demonstrate that LHRHa can effectively induce mature sea bass to spawn independent of the highly predictable semilunar spawning rhythm. In addition, the occurrence of both spontaneous and hormone‐induced spawnings at a precise period of the day suggest a tidal and diurnal cue entraining spawning of mature female sea bass.