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Bibliography of the Maurice Lamontagne Institute

Marie-France BEAULIEU

HARVEY, M., J.-F. ST-PIERRE, L. DEVINE, A. GAGNÉ, Y. GAGNON, M.F. BEAULIEU, 2005. Oceanographic conditions in the Estuary and the Gulf of St. Lawrence during 2004 : zooplankton ; Conditions océanographiques dans l’estuaire et le golfe du St-Laurent en 2004 : zooplancton. DFO, Canadian Science Advisory Secretariat, Research Document ; MPO, Secrétariat canadien de consultation scientifique, Document de recherche, 2005/043, 22 p .

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Zooplankton biomass, abundance, and species composition in the Québec Region (Lower St. Lawrence Estuary and Gulf of St. Lawrence) during 2004 are reviewed and related to conditions during the preceding years and over the longer term where applicable. In addition, this report gives an overview of the interannual variability of the mesozooplankton biomass and the macrozooplankton species composition, abundance, and biomass in the Lower Estuary (LE) and the northwest Gulf of St. Lawrence (NWGSL) as measured in fall of each year between 1994 and 2004. Even with only four zooplankton samples collected in February, March, June and November 2004, at both Québec fixed stations in 2004, we can see that the zooplankton biomass follow the same temporal variations pattern then during the 5 previous years (1999-2003). Furthermore, the zooplankton biomass observed in February, March, June and November were comparable to the one observed previously (1999-2003) at the same period of the year except in June and November in the Anticosti gyre were the zooplankton biomass was ca 2 times lower than normal. Hierarchical community analysis revealed that copepods continue to numerically dominate the zooplankton year-round at both Québec fixed station in 2004. The depth-integrated abundance of the different Calanus finmarchicus stages reveled that the reproductive success of C. finmarchicus seems to have been lower in 2004 than during the previous years at both fixed stations. The overall abundance and biomass of zooplankton observed in 2004 along all sections in spring and fall were comparable to observations made since 2000. The mean mesozooplankton biomass observed in November 2004 in the LE and the NWGSL was 1.3 times lower than in 2003 and corresponded to the second lowest value observed since the last 10 years in the study area. On the other hand, the mean macrozooplankton biomass observed in 2004 was 1.2 times higher than in 2003. The most notable feature observed in the LE and the NW GSL was that 2004 had the lowest mean biomass of euphausiids in the last decade and that for the first time the mean biomass of the hyperiid amphipod T. libellula was higher than the mean biomass of euphausiids. Finally, the mean abundance of both the chaetognaths and the jellyfish observed in 2004 corresponded to the highest value of the time series and were up 8.5 and 10.5 times higher than the average value of the last ten years respectively.

HARVEY, M., J.-F. ST-PIERRE, L. DEVINE, A. GAGNÉ, Y. GAGNON, M.F. BEAULIEU, 2004. Oceanographic conditions in the Estuary and the Gulf of St. Lawrence during 2003: zooplankton ; Conditions océanographiques dans l’estuaire et le golfe Saint-Laurent en 2003: zooplancton. DFO, Canadian Science Advisory Secretariat, Research Document ; MPO, Secrétariat canadien de consultation scientifique, Document de recherche, 2004/061, 31 p .

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Zooplankton biomass, abundance, and species composition in the Québec Region (Lower St. Lawrence Estuary and Gulf of St. Lawrence) during 2003 are reviewed and related to conditions during the preceding years and over the longer term where applicable. In addition, this report gives an overview of the interannual variability of the mesozooplankton biomass and the macrozooplankton species composition, abundance, and biomass in the Lower Estuary and the northwest Gulf of St. Lawrence as measured in September of each year between 1994 and 2003. The zooplankton biomass and abundance at the Québec fixed stations in 2003 were slightly higher than observations made in 2000, 2001, and 2002 at both stations. The relative proportion of copepods vs. the other groups of mesozooplankton increased from 70 to 95 % between 1999 and 2003 in the Gaspé Current (GC) and from 70 to 85 % between 1999 and 2001 in the Anticosti Gyre (AG). No larvacea were found at both fixed stations in 2003. The depth-integrated abundance of the Calanus finmarchicus stage composition showed that there were two periods of reproduction for this species at both stations in 2003. Reproduction occurred in summer (June-July) and fall (September-October) and was synchronized at both stations. The same situation was observed in 2000, 2001, and 2002. In 2003, the abundance of Calanus finmarchicus reached record high level since 1999 at both fixed stations (GC and AG). The zooplankton biomasses and abundances observed in early spring, late spring, and fall 2003 along the six AZMP sections were comparable to observations made in 2002, 2001, and 2000. The mesozooplankton biomass in the Lower Estuary and the northwest Gulf of St. Lawrence in 2003 was slightly higher than in 2002 while the macrozooplankton biomass was comparable to the 2002 level. The year 2003 was characterized by a significant increase in the mean abundance of the pelagic amphipod Themisto libellula and the mysid Boreomysis arctica and a significant decrease in the mean abundance of the chaetognath Sagitta elegans and the gelatinous zooplankton Aglantha digitale, Obelia spp., and Boreo spp. The significant relationships between the mean annual abundance of the hyperiid amphipod T. libellula and the percentage of Labrador Shelf water supported the hypothesis that the significant increase in the mean abundance of this species observed in 2001, 2002, and 2003 in the Lower Estuary and the Gulf of St. Lawrence is associated with the intrusion of the cold Labrador Shelf water into the Gulf of St. Lawrence via the Strait of Belle Isle (Harvey et al 2003).

HARVEY, M., J.-F. ST-PIERRE, A. GAGNÉ, M.F. BEAULIEU, Y. GAGNON, 2003. Oceanographic conditions in the Estuary and the Gulf of St. Lawrence during 2002 : zooplankton ; Conditions océanographiques dans l’estuaire et le golfe du St-Laurent en 2002 : zooplancton. DFO, Canadian Science Advisory Secretariat, Research Document ; MPO, Secrétariat canadien de consultation scientifique, Document de recherche, 2003/077, 23 p .

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Zooplankton biomass, abundance, and species composition in the Québec region (Lower St.Lawrence Estuary and Gulf of St. Lawrence) during 2002 are reviewed and related to conditions during the preceding year and over the longer-term where applicable. In addition, this report gives an overview of the interannual variability of the mesozooplankton biomass and the macrozooplankton species composition, abundance, and biomass in the Lower Estuary and the northwest Gulf of St. Lawrence as measured in September in each year between 1994 and 2002. The zooplankton biomass and abundance in the Québec fixed stations in 2002 were comparable to conditions observed in previous years except in the Gaspé current were the mean integrated zooplankton biomass was 1.5 times higher in 2002 than in 2001 and 2000. Copepod eggs, juveniles, and adults were clearly dominant, accounting for more than 80% of the zooplankton community for all sampling dates in the Anticosti Gyre and the Gaspé Current. The depthintegrated abundance of the stage composition of Calanus finmarchicus showed that in 2002 there was two periods of reproduction for this species in both stations. The first and the second period of reproduction occurred in summer (June-July) and fall (September-October) respectively and were synchronized in both stations. The same situation was observed in 2001 and 2000. The zooplankton biomasses observed in spring and fall 2002 along the six AZMP sections were comparable with observations made in 2001 and 2000. The zooplankton abundance was higher than in 2001 in both the LSLE and the Gulf of St. Lawrence but comparable to the levels observed in 2000. The mesozooplankton biomass in the Lower Estuary and the northwest Gulf of St. Lawrence in 2002 was slightly higher than in 2001 while the macrozooplankton biomass was comparable to the level of 2001. The year 2002 was characterized by a significant increase of the mean abundance the chaetognath Sagitta elegans, the gelatinous zooplankton Aglantha digitale, Obelia sp., and Boreo sp., and the pelagic amphipod Themisto abyssorum and a significant decrease of the mean abundance of the mysid Boreomysis arctica.

GRÉGOIRE, F., J. LAMBERT, C. LÉVESQUE, M.-F. BEAULIEU, 1997. Évaluation de la biomasse du maquereau bleu (Scomber scombrus L.) pour 1996 par la Méthode de la Production Totale d'oeufs ; Assessment of the Atlantic mackerel (Scomber scombrus L.) biomass for 1996 by the Total Eggs Production Method. MPO, Secrétariat canadien pour l'évaluation des stocks, Document de recherche ; DFO, Canadian Science Advisory Secretariat, Research Document, 97/71, 29 p .

The 1996 survey to assess the Atlantic mackerel biomass began three days later than planned, on June 18. On the first set, surface water temperatures were noted to be higher than during the initial sets of previous surveys. Furthermore, eggs at later development stages and mackerel larvae were more numerous. Daily egg production for the two sets was evaluated at 0.6604 x 1013 and 0.6129 x 1013 eggs, with corresponding spawning biomass values of 259,842 t and 241,318 t. The biomass values fell to 211,023 t and 206,566 t when the egg densities at each station were corrected for the oversampling that occurs at the end of tows. When these corrected densities were applied in the geostatistical approach, daily production values of 0.6068 x 1013 and 0.6366 x 1013 eggs were obtained for the sets, yielding biomass values of 238,897 t and 250,628 t. Using this approach, it was also determined that there is a close relationship between egg density and water temperature. This relationship can be used to improve abundance estimates in the future. Because the timing of the survey and spawning were not well synchronized and owing to the method used to derive the seasonal egg production curve, the abundance estimate for 1996 should be considered a minimal value.