Effect of water temperature on individual reproductive activity of pollack (Pollachius pollachius)
2005
Suquet, Marc | Normant, Yvon | Gaignon, Jean-louis | Quemener, Loic | Fauvel, Christian
The effects of water temperature on pollack (Pollachius pollachius) spawning features were individually assessed. During the spawning period, nine fish sets, each composed of one female and two males (mean body weight: 2.5+/-1.0 kg), were placed in small-volume tanks (2 m(3)). Fish sets were held at 8, 10, or 12 degreesC (n=3 for each temperature). Three females released eggs at 8 and 10 degreesC, while only two spawned at 12 degreesC. One hundred thirty-one individual spawns were collected from the eight spawning fish sets. The number of spawns collected per female was significantly lower at 12 degreesC (3.0+/-3.6), compared to 10 degreesC (17.3+/-10.1) and 8 degreesC (23.3+/-2.5). Egg number (eggs kg(-1) BW) was significantly lowered at 12 degreesC (26,068+/-35,989) compared to 10 degreesC (323,230+/-136,796) and 8 degreesC (599,612+/- 249,545). The number of viable eggs (eggs kg-1 BW) was significantly lower at 12 degreesC (4,175+/-7,167) compared to 8 degreesC (192,034+/-145,870). When incubated at a common temperature of 10 degreesC, hatching and malformation percentages were significantly enhanced for breeders maintained at 8 degreesC (respectively, 35.8+/-8.5-7.3+/-1.4%) compared to 10 degreesC (9.8+/-8.0-2.3+/-1.8%). Then, pooling data were recorded at the three temperatures; a significant decrease of egg diameter with time was observed. The individual reproductive activity of pollack experienced by breeders was deeply affected by temperature during the spawning period. A temperature of 12 degreesC is suggested to be close to the temperature reproduction upper limit in this species.
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