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Bibliography of the Maurice Lamontagne Institute

Isabelle D'AUTEUIL

D'AUTEUIL, I., F. GRÉGOIRE, 1993. Description histologique du développement des ovocytes chez le maquereau bleu (Scomber scombrus L.) du golfe du Saint-Laurent. Rapp. tech. can. sci. halieut. aquat., 1912, 23 p .

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The reproductive stock size of the Gulf of St. Lawrence mackerel is currently calculated using to the total egg production model. Female fecundity, one of the most important variables in this model, is determined as being the number of oocytes having a diameter greater than 140 µ just before spawning. This definition of the fecundity is inadequate for indeterminate serial spawners such as the anchovy and the mackerel. The batch fecundity method involves defining the fecundity of these fishes by multiplying the number of oocytes expelled per batch by the number of batches spawned during the spawning season. To determinate theses variables, the different phases in the development of the oocyte must be examined and described. In the case of the Gulf of St. Lawrence mackerel, an histological study was carried out on gonads gathered during the 1991 spawning season. The histological structures identified are similar to those observed with European mackerel. The oocyte size frequency distributions are multimodal with overlapping modes, which is characteristic of indeterminate serial spawners. The simultaneous presence of hydrated oocytes and post-ovulatory follicles was noted. Since the presence of empty follicles is an indication that spawning has started, gonads having these two structures at the same time should not be included in the calculation of the batch fecundity.

D'AUTEUIL, I., F. GRÉGOIRE, 1993. Histological description of oocyte development in Atlantic mackerel (Scomber scombrus L.) in the Gulf of St. Lawrence. Can. Tech. Rep. Fish. Aquat. Sci., 1912, 23 p .

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The reproductive stock size of the Gulf of St. Lawrence mackerel is currently calculated using to the total egg production model. Female fecundity, one of the most important variables in this model, is determined as being the number of oocytes having a diameter greater than 140 µ just before spawning. This definition of the fecundity is inadequate for indeterminate serial spawners such as the anchovy and the mackerel. The batch fecundity method involves defining the fecundity of these fishes by multiplying the number of oocytes expelled per batch by the number of batches spawned during the spawning season. To determinate theses variables, the different phases in the development of the oocyte must be examined and described. In the case of the Gulf of St. Lawrence mackerel, an histological study was carried out on gonads gathered during the 1991 spawning season. The histological structures identified are similar to those observed with European mackerel. The oocyte size frequency distributions are multimodal with overlapping modes, which is characteristic of indeterminate serial spawners. The simultaneous presence of hydrated oocytes and post-ovulatory follicles was noted. Since the presence of empty follicles is an indication that spawning has started, gonads having these two structures at the same time should not be included in the calculation of the batch fecundity.