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BUI, A.O.V., M. CASTONGUAY, P. OUELLET, 2012. Distribution et abondance des larves et juvéniles de poissons dans lestuaire maritime du St-Laurent : connectivité entre le Golfe, lEstuaire et le Fjord du Saguenay ; Distribution and abundance of larval and juvenile fish in the lower St. Lawrence Estuary : connectivity among the Gulf, the Estuary, and the Saguenay Fjord. Rapp. tech. can. sci. halieut. aquat. ; Can. Tech. Rep. Fish. Aquat. Sci., 2981, 57 p .
This study greatly improved knowledge of the distribution and abundance of ichthyoplankton communities and of oneand two-year-old juveniles of demersal species in the Lower St. Lawrence Estuary. Data analysis revealed that the ichthyoplankton community in the Lower Estuary consisted mainly of non-commercial demersal species, while the species targeted in the Saguenay Fjord ice fishing (mainly redfish, Atlantic cod, and Greenland halibut or turbot) were present in the Lower Estuary at the juvenile stage. This suggests connectivity for these species among the Gulf of St. Lawrence, the Lower Estuary, and the Saguenay Fjord. Our results support the hypothesis that recruitment of redfish, cod, and Greenland halibut in the Saguenay Fjord is based on the immigration of juvenile fish from the Estuary.
BENOÎT, H.P., J.A. GAGNÉ, C. SAVENKOFF, P. OUELLET, M.-N. BOURASSA, 2012. State-of-the-Ocean report for the Gulf of St. Lawrence Integrated Management (GOSLIM) area. Can. Manuscr. Rep. Fish. Aquat. Sci., 2986, 81 p .
This document is part of an initiative conducted by the Canadian Department of Fisheries and Oceans to report on the ecological "State of the Oceans" (SOTO). It concisely summarizes the most recent scientific information relevant to six key issues that have a considerable impact on the ecosystems of the Estuary and Gulf of St. Lawrence Large Ocean Management Area (LOMA): (1) hypoxia in the deep waters, (2) ocean acidification, (3) changes in seasonal sea-ice cover and its effect on marine mammals, (4) aquatic invasive species, (5) impacts of fishing and climate-driven changes in exploited marine populations and communities, and (6) potential impacts of grey seal predation on groundfish populations. The information is presented following the Drivers Pressures State Impacts and Responses approach (DPSIR) to the identification and management of the environmental effects. Existing reports on the structure, state, and management of the Estuary and Gulf of St. Lawrence LOMA are also reviewed with the aim to highlight the manner in which the present report complements that information. Furthermore, a brief discussion on what should constitute the structure and content of a more effective SOTO report is presented as an explanation for the nature of the present report and as a guide for future SOTO reporting in the LOMA. The report results from a collaboration between ocean scientists and managers in support of integrated management in the St. Lawrence LOMA.
BUI, A.O.V., M. CASTONGUAY, P. OUELLET, J.-M SÉVIGNY, 2011. Searching for Atlantic Cod (Gadus morhua) spawning sites in the northwest Gulf of St Lawrence (Canada) using molecular techniques. ICES J. Mar. Sci., 68(5): 911-918 .
The overexploitation of Atlantic cod (Gadus morhua) in the Northwest Atlantic led to the collapse of most stocks and the demise of spawning components in the early 1990s. In the northern Gulf of St Lawrence, the spawning component of Northwest Atlantic Fishery Organization Division 4S was believed no longer to exist after the collapse. To verify this hypothesis, we used molecular techniques to identify cod, haddock, and witch flounder (CHW) eggs precisely, in an attempt to locate the potential remaining spawning sites for cod in the northwest Gulf. Ichthyoplankton surveys were conducted in spring from 2005 to 2008. Results were compared with those of surveys that took place in spring in the same area 20 years earlier to determine if there had been any changes in spawning location and egg abundance. Atlantic cod made up the majority (97 %) of CHW eggs identified. The presence of stage I cod eggs proved that there is still a cod spawning component in the northwest Gulf of St Lawrence, but egg abundance has declined by about an order of magnitude compared with the 1980s. There was no obvious difference in the location of cod spawning grounds between the two decades
OUELLET, P., C. FUENTES-YACO, L. SAVARD, T. PLATT, S. SATHYENDRANATH, P. KOELLER, D. ORR, H. SIEGSTAD, 2011. Ocean surface characteristics influence recruitment variability of populations of Northern Shrimp (Pandalus borealis) in the Northwest Atlantic. ICES J. Mar. Sci., 68(4): 737-744 .
Remotely sensed data were used to derive simple ecosystem indicators for four regions of the Northwest Atlantic to test the hypothesis that sea surface temperatures (SSTs) and spring phytoplankton bloom characteristics (initiation, timing, intensity, and duration) have a significant influence on larval survival and recruitment of northern shrimp (Pandalus borealis). For all years (1998–2007) and regions, hatching was after the initiation of the bloom and before or after the bloom reached its maximum intensity. The results suggest that the best survival of larvae is associated with high warming rates of SST following hatching, but in very cold environments, warm temperatures at hatching seem to be important for larval survival. The analyses also indicate that larval survival is supported by an early, long phytoplankton bloom which attains high concentrations of chlorophyll a. The results demonstrate the potential of remotely sensed data for deriving simple population-specific ecosystem indicators for potential use in building operational recruitment models for predicting changes in northern shrimp abundance.
BUI, A.O.V., P. OUELLET, M. CASTONGUAY, J.-C. BRÊTHES, 2010. Ichthyoplankton community structure in the northwest Gulf of St. Lawrence (Canada) : past and present. Mar. Ecol. Prog. Ser., 412: 189-205 .
Biodiversity can play an important role in the stability and resilience of ecosystems when these are faced with environmental change or anthropogenic impacts. Historically, the northwest Gulf of St. Lawrence had high fish egg and larval productivity. To assess changes in the ichthyoplankton community of this region, data from sampling surveys that were carried out in spring from 1985 to 1987 were compared with data from spring 2005 to 2007. Significant differences in ichthyoplankton abundances between the 2 decades and sampling times (May versus June) were revealed by multivariate analyses (nMDS, ANOSIM, PERMANOVA, and SIMPER) and univariate (ANOVA) analyses. Total ichthyoplankton abundance was lower in the 2000s than during the mid- 1980s. Although larval sandlance Ammodytes spp. abundances did not change significantly, other taxa, such as Stichaeidae larvae and H4B eggs (gadids and merlucciid hakes, rocklings, butterfish Peprilus triancanthus, windowpane Scophthalmus aquosus and Gulf Stream flounder Citharichthys arctifrons), became more abundant; the abundance of CHW eggs (cod Gadus morhua, haddock Melanogrammus aeglefinus, witch flounder Glyptocephalus cynoglossus), and redfish Sebastes spp. larvae generally declined by more than an order of magnitude. Greenland halibut Reinhardtius hippoglossoides larvae also appeared in the 2000s assemblages. This dominance shift in the ichthyoplankton community reflects the demise of large fish predators and the response of the non-commercial species. Our study provides much-needed new information concerning current biodiversity and productivity of the fish community in the Gulf of St. Lawrence and insights into changes influenced by groundfish collapse and environmental fluctuations.©2010 Inter-Research
ARIZA, P., P. OUELLET, 2009. Diet components of Northern Shrimp Pandalus borealis first stage larvae in the northwest gulf of St. Lawrence. J. Crust. Biol., 29(4): 532-543 .
The objective of this study was to clarify the diet composition of the first stage larvae of northern shrimp Pandalus borealis¨ during the spring period of high biological production in the Northwestern Gulf of St. Lawrence (NWGSL). Data collected in spring 2006 revealed that hatching of P. borealis larvae took place in late April and early May during a period characterized by a phytoplankton bloom (mainly species of the genus Chaetoceros) and by an abundance of early stages of mesozooplankton, which demonstrated the onset of secondary production at the sampling site. Gut content examination of stage I larvae sampled at the site and feeding experiments conducted at sea revealed that omnivorous feeding starts at hatching, but a first approximation based on the quantity of pigments present in the larvae suggest that zooplankton is more important than phytoplankton to meet the larvaes energy needs. In addition, field observations of the degree of gut fullness and the low percentage (10 %) of larvae with empty guts indicate a high feeding success. Hatching at the time of production of adequate prey could represent a major factor for larval northern shrimp survival in the NWGSL.©2009 The Crustacean Society
GENDRON, L., P. OUELLET, 2009. Egg development trajectories of early and late-spawner lobsters (Homarus americanus) in the Magdalen Islands, Québec. J. Crust. Biol., 29(3) : 356-363 .
This study examines egg development in American lobster (Homarus americanus) ovigerous females caught off the Magdalen Islands (MI), Québec, in September 2002 and kept in tanks for 10-11 months under a simulated natural temperature cycle. The study compares egg development trajectories of 7 early-spawners (ES) that had a well-defined pigmented eye area (Perkins eye index, PEI: 190-246 μm) at the time of capture and 8 late-spawners (LS) with no visible pigmented eye at the time of capture. Eggs from ES achieved about 80 % of their development in the fall, followed by a circa 6-months rest period. Eggs from LS reached approximately 50 % development by late fall, and unlike eggs from ES, continued development during winter even at temperatures of 1.0-1.5 °C. The two groups experienced different numbers of effective (>3.4 °C) degree-days (ES: 1440.7, LS: 1308.0) for complete embryonic development and late spawning translated into late hatching. Additional observations made on a group of 72 ovigerous MI females caught in September 2006 indicate that early spawning is mainly associated to larger females, most likely multiparous, with a 2-year reproductive cycle, and late spawning mainly to smaller females, most likely primiparous, with a 1-year cycle, molting and spawning the same year. Larvae from ES/ multiparous and LS/primiparous may therefore encounter different environmental conditions for survival at hatching and during larval development. The occurrence of females having different patterns of egg development trajectories in American lobster populations can help spread larval production over time. This can be viewed as a mechanism for coping with environmental uncertainty.©2009 The Crustacean Society
DUFOUR, R., P. OUELLET, 2007. Rapport d'aperçu et d'évaluation de l'écosystème marin de l'estuaire et du golfe du Saint-Laurent. Rapp. tech. can. sci. halieut. aquat., 2744F, 123 p .
The reports main objective is to provide a descriptive overview of the components, structure and functioning of the Estuary and Gulf of St. Lawrence ecosystem, as well as a preliminary evaluation of the main pressures exerted by human activities at the ecosystem level. In doing so, the report identifies species/populations and geographical areas, including marine coastal areas, which are either significant at the ecosystem level and/or of concern regarding the threat and impacts of human pressure on the Estuary and Gulf of St. Lawrence ecosystem.
OUELLET, P., L. SAVARD, P. LAROUCHE, 2007. Spring oceanographic conditions and northern shrimp Pandalus borealis recruitment success in the north-western Gulf of St. Lawrence. Mar. Ecol. Prog. Ser., 339 : 229-241 .
Time series of sea-surface temperature (SST), thermally mixed layer depth, and the SST warming rate in spring at the time of larval emergence were correlated with indices of northern shrimp Pandalus borealis recruitment (cohort abundance and larval survival index) between 1994 and 2003 in the northwest Gulf of St. Lawrence, Canada. The recruitment index and larval survival index were negatively correlated to daily mean SST at the time of larval emergence. The recruitment index and larval survival index were positively correlated with the SST warming rate and with the mixed layer depth at the time of larval emergence. Overall, the analysis reveals that larval emergence during a period of weak density stratification and low SST in the spring, but followed by relatively high warming rates of the upper layer of the water column, is favourable for larval survival. We suggest that the observed relationships support the hypothesis that oceanographic conditions in the upper layer of the water column, which initiate and sustain high levels of biological production at the time of larval emergence and early development, are favourable for northern shrimp recruitment success. Thus, interannual variability in northern shrimp recruitment in the northwest Gulf of St. Lawrence may be explained by Cushings match/mismatch hypothesis. ©2007 Inter-Research
OUELLET, P., A. BUNDY, E.M.P. CHADWICK, A.-M. MACKINNON, O. SCHIMNOWSKI, 2007. Atelier national des Sciences 2006, Pêches et Océans Canada, Institut Maurice-Lamontagne, Mont-Joli (Québec) ; National Science Workshop 2006, Fisheries and Oceans Canada, Maurice Lamontagne Institute, Mont-Joli (Québec). Rapp. tech. can. sci. halieut. aquat. ; Can. Tech. Rep. Fish. Aquat. Sci., 2721, 65 p .
DUFOUR, R., P. OUELLET, 2007. Estuary and Gulf of St. Lawrence marine ecosystem overview and assessment report. Can. Tech. Rep. Fish. Aquat. Sci., 2744E, 112 p .
The reports main objective is to provide a descriptive overview of the components, structure and functioning of the Estuary and Gulf of St. Lawrence ecosystem as well as a preliminary evaluation of the main pressures exerted by human activities at the ecosystem level. In doing so, the report identifies species/populations and geo-graphical areas, including marine coastal areas, that are either significant at the ecosystem level and/or of concern regarding the threat and impacts of human pressure on the Estuary and Gulf of St. Lawrence ecosystem.
OUELLET, P., L. SAVARD, P. LAROUCHE, 2007. Spring oceanographic conditions and northern shrimp Pandalus borealis recruitment success in the northwestern Gulf of St. Lawrence. AZMP Bull. PMZA, 6: 47-52 .
[Abstract only available in French]
Des séries temporelles de la température de surface (TS), de la profondeur de la couche mélangée (en température) et du taux de réchauffement de TS au printemps au moment de lémergence des larves de crevettes ont été corrélées à des indices de recrutement de la crevette nordique (Pandalus borealis) entre 1994 et 2004 dans le nord-ouest du golfe du Saint-Laurent, Canada. Lindice de la survie larvaire était corrélé négativement avec la moyenne journalière de TS au moment de lémergence des larves de crevettes. Lindice de la survie larvaire était corrélé positivement avec le taux de réchauffement de TS et la profondeur de la couche mélangée au moment de lémergence des larves. Dans leur ensemble, les analyses ont révélé que lémergence des larves de crevettes pendant une période de faibles stratifications de densité et de faibles TS au printemps, suivi dun taux de réchauffement relativement élevé dans la couche supérieure de la colonne deau est favorable à la survie des larves. Notre étude montre aussi limportance dun monitorage des conditions océanographiques tôt au printemps dans lécosystème du nord du golfe du Saint-Laurent.
OUELLET, P., 2007. Contribution à l'identification de zones d'importance écologique et biologique (ZIEB) pour l'estuaire et le golfe du Saint-Laurent : la couche des ufs et des larves de poissons et de crustacés décapodes ; Contribution to the identification of ecologically and biologically significant areas (ESBA) for the Estuary and the Gulf of St. Lawrence : the fish eggs and larvae and crustacean decapods larvae layer. MPO, Secrétariat canadien de consultation scientifique, Document de recherche, 2007/011, 66 p .
An analysis on more than 20 years of data on the abundance of fish eggs and larvae and for few crustacean decapod species is presented to draw a map of ecologically and biologically significant areas for the Gulf of St. Lawrence and Estuary. The analysis of the spatial distribution of eggs and larvae of fish species and of crustacean decapods species leads to the suggestion of eight areas for the entire Gulf and Estuary system. The principal areas are located around Anticosti Island, the west coast of Newfoundland and in the southern Gulf. However, an absence of data available for mapping in the Estuary limits the value of the analysis for that region of the St. Lawrence system.
OUELLET, P., J.-P. ALLARD, 2006. Vertical distribution and behaviour of shrimp Pandalus borealis larval stages in thermally stratified water columns: laboratory experiment and field observations. Fish. Oceanogr., 15(5): 373-389 .
By combining field data and laboratory observations of larvae in a simulated thermal gradient, we described the ontogenetic changes in vertical distribution and behaviour of early stages of shrimp Pandalus borealis in thermally stratified water columns. Both in the laboratory and at stations in the north-western Gulf of St Lawrence, the first two larval stages appear to actively select and maintain a position in the upper layer of warmer temperatures, within the thermocline and above the cold (<1 °C) intermediate layer. Stage III larvae were distributed deeper in the water column and in colder waters than the previous two stages. Stage IV and V larvae showed the highest degree of swimming activity in the laboratory and a much wider range (from surface to ˜200 m) in vertical distribution in the field. The shift to deeper waters and settlement to the bottom habitat appears to happen after the fifth moult, at stage VI. We propose that the pattern of vertical distribution in the field reflects the adjustment of the different developmental stages to the distribution of preferred prey. The description of the ontogenetic change in the vertical distributions and movements of early stages of P. borealis should be valuable information for future attempts to model larval transport and dispersion, and for detecting settlement/recruitment areas using 3D ocean circulation models. The identification of the thermal habitat of the different larval stages and the timing for settlement at the bottom also provides important information for the development of temperature-dependent growth models up to the first juvenile stages. ©2006 Her Majesty in Right Canada
CHABOT, D., P. OUELLET, 2005. Rearing Pandalus borealis larvae in the laboratory. II. Routine oxygen consumption, maximum oxygen consumption and metabolic scope at three temperatures. Mar. Biol., 147(4): 881-894 .
Larvae of the northern shrimp Pandalus borealis (Krøyer) are pelagic. In the Estuary and Gulf of St. Lawrence, Canada, the early stages are found in the upper 25-m of the water column in spring and early summer and are expected to experience a range of water temperatures from as low as 0 °C to as high at 6 °C. Little is known of the impact of water temperature on metabolic requirements of northern shrimp larvae. In this study, routine respiration (VO2), maximum respiration (electron transport system activity, ETSA) and metabolic scope for growth (MS, ETSA-VO2) of northern shrimp larvae were measured as a function of temperature (3, 5 and 8 °C), developmental stage (I-V at 3 °C, I-VII at 5 °C and 8 °C) and growth rate in dry mass. After logarithmic transformation, all three metabolic variables were linearly related to dry mass. The increase in VO2 with body mass was faster at 5 °C than at 3 or 8 °C, whereas with ETSA this increase was slower. As a result, MS increased more slowly with dry mass at 5 °C than at 3 and 8 °C. However, MS did not limit growth in this study, since it explained only 39 % of the variability in growth. All three metabolic variables as well as growth varied together as a function of temperature and ontogeny. Q10 of all three metabolic variables ranged from 1.6 and 2.2 for stages I-V larvae, except for VO2 at stage I (3.9) and stage III (2.9).©2005 Springer-Verlag
OUELLET, P., 2005. Final report of the Fisheries Oceanography Committee 2005 annual meeting : March 22-24, 2005, Gulf Fisheries Center, Moncton, New Brunswick ; Rapport final de la réunion annuelle de 2005 du Comité sur l'océanographie des pêches : 22-24 mars 2005, Centre des pêches du Golfe, Moncton, Nouveau-Brunswick. DFO, Canadian Science Advisory Secretariat, Proceedings Series ; MPO, Secrétariat canadien de consultation scientifique, Série des comptes rendus, 2005/015, 53 p .
The Fisheries Oceanography Committee of the Department of Fisheries and Oceans met in Moncton, New Brunswick, on 22-24 March 2005. The committee reviewed environmental conditions in the Northwest Atlantic during 2004, reviewed additional papers on physical and biological oceanography, and conducted its annual business meeting. 1- Physical Environment in 2004: During winter, the NAO index was below normal for the fourth consecutive year and close to the 2001 value. A negative NAO index implies weaker winds, higher air temperatures, and reduced heat loss from the ocean during winter over the Labrador Sea and partly over the Labrador and Newfoundland Shelf. Annual average air temperatures were above normal by ca. 1.2 °C over the Labrador Sea and Shelf, the Newfoundland Shelf, and the Gulf of St. Lawrence. However, the Scotian Shelf and Gulf of Maine air temperatures were below normal (ca. -0.4 °C). The Newfoundland ice coverage was the 2nd lowest in 42 years and its duration was generally below the average. In the Gulf of St. Lawrence, ice coverage was also lower than normal (11th lowest of last 42 years) and its duration was shorter than average. On the other hand, the Scotian Shelf featured unexceptional coverage with ice duration slightly longer than normal. Satellite data indicate a north-south gradient of seasurface temperatures similar to the air temperature distribution. The Labrador Sea and Shelf, the northern Newfoundland Shelf, and northern Grand Bank featured sea-surface temperature anomalies that were between 0.2 and 0.5 °C above normal. Above-normal sea-surface temperatures were seen in the north-eastern Gulf of St. Lawrence, but the rest of the Gulf had values slightly below normal. In contrast, sea-surface temperatures on the Scotian Shelf and in the Gulf of Maine were between 0.3 and 1.1 °C below normal. The analyses of regional data (mainly from the Atlantic Zone Monitoring Program - AZMP) showed that, similar to 2003, cool conditions tended to dominate the Scotian Shelf (SS) and the eastern Gulf of Maine in 2004. The sea-surface temperature near St. Andrews was 0.8 °C below normal. At Prince 5 fixed station (Bay of Fundy), the integrated monthly mean temperatures between 0 and 90 m were generally below normal by ca. 0.9 °C. Salinities were within 0.1 of normal throughout the year. At the Halifax-2 fixed station, sea-surface temperature was 1.0oC below normal, making 2004 one of the coldest of the last 79 years, and depthintegrated temperature anomalies were ca. - 1 °C (salinity was close to normal). Data from the AZMP standard sections in April, May, and October support the overall conclusion of temperatures ca. 2.0 °C below normal on the SS accompanied by an extensive cold intermediate layer. The temperatures from the July groundfish survey were exceptional, with a very broad cold intermediate layer and below-normal temperatures at 50 m, 100 m, and the bottom. The overall stratification index was slightly below normal for the SS region. The Shelf/Slope front and the Gulf Stream were about 20 km south of their mean positions. The annual averaged water column temperature at Station 27 (NL) for 2004 remained above the long-term mean and reached the highest value on record. The annual surface temperature at Station 27 was 1.0 °C above normal, also the highest on record, while the annual bottom temperature was the highest since 1966. The annual averaged water column salinities at Station 27 remained above normal for the 3rd consecutive year. The cross-sectional area of water <0 °C (the CIL) on the Newfoundland and Labrador Shelf during the summer decreased compared to 2003, remaining below the long-term mean along all sections. The CIL areas were below normal along all sections from the Flemish Cap section on the Grand Bank to the Seal Island section off southern Labrador. Off Bonavista, for example, the CIL area was below normal for the 10th consecutive year. The areas of the CIL on the Newfoundland Shelf in recent years are in sharp contrast to the near record-high values measured during the extremely cold years of the early 1990s. During the spring of 2004, bottom temperatures over St. Pierre Bank increased significantly relative to 2003, with <0 °C water restricted to the deep approaches to Placentia Bay. Consequently, above-normal temperatures were more widespread during 2004 compared to 2003, covering most of the bottom areas of the banks in NAFO Division 3P, with values as high as 1.0 °C above the long-term mean. In Division 3LNO, spring bottom temperatures were above normal in all areas of the Grand Banks by 1.0 to 1.5 °C. As a result, the spring of 2004 had the lowest area of <0 °C water in Division 3L since the surveys began in the early 1970s. Bottom temperatures during the fall of 2004 were predominately above normal in all areas by 0.5 to 2.0 °C and were the highest on record in Division 2J. In the Gulf of St. Lawrence, spring air temperatures in 2004 were colder than normal but reversed to above normal in the fall. There was an increase in the minimum temperature of the CIL and a reduction of the area of the bottom (southern Gulf) with temperatures ≤0 °C relative to 2003. 2- Biological Environment in 2004: The analyses of regional data (mainly from the AZMP) showed that nitrate concentrations in surface waters were higher in winter at the Halifax-2 and Prince-5 fixed stations and lower in summer at Halifax-2 than in previous years. Below the surface (>50 m), nitrate concentrations were lower than in previous years at both fixed stations and considerably lower than the climatological mean. Nitrate concentrations were also lower than observed in previous years in the bottom waters of the SS in summer 2004 but higher in the bottom waters of the southern Gulf of St. Lawrence in the fall. In 2004, one dominant feature on the SS was a strong and widespread spring bloom (chlorophyll a concentrations close to the record high observed in 2003). This was especially evident at the Halifax-2 fixed station, at the spring sections on the eastern and western SS, and in the southern Gulf and Georges Bank as determined by satellite data. The CPR data continue to show that contemporary phytoplankton abundances are above the long-term average and that the growth cycle starts earlier. Zooplankton biomass and Calanus finmarchicus abundance were lower in 2004 than in previous years at the Shediac Valley fixed station (southern Gulf) and in spring on the central and western SS. C. finmarchicus biomass and abundance were higher in the central and eastern SS and in the southern Gulf in the fall. Nutrient inventories in the surface layer at Station 27 (NL) increased from the 2000-2003 average and bottom inventories remained low relative to 2000. The onset and duration of the spring bloom were near the long-term averages, with the bloom starting in the last week of March and lasting until late May, but the magnitude was lower than in 2003. Satellite observations of the NL mid shelf showed that the April 2004 spring bloom returned to a normal period compared to the late blooms observed from 2000 to 2003. The copepod C. finmarchicus abundance at Station 27 was lower than the previous three years and substantially lower than in 1999 and 2000. The abundance and occurrence of copepod species associated with cold and warm waters, which had shown a gradual shift toward cold-water species since 1999, shifted back toward warm-water species in 2003, a pattern that continued in 2004. Across the NL Shelf, overall copepod abundance appeared to have been at the highest levels (with the exception of Southeast Shoal) since the start of the AZMP. The abundances of three species of Calanus (finmarchicus, hyperboreus, glacialis) and large Calanus nauplii were the lowest on record for the Flemish Cap transect while their abundance levels were at their highest levels since 2000 on the Bonavista Bay and Seal Island transects. No phytoplankton bloom was observed at the Rimouski fixed station in the Lower St. Lawrence Estuary (LSLE) in 2004, and the spring-summer phytoplankton biomass was the lowest since 1992. That situation was possibly due to above-normal freshwater runoff in the region in spring-summer 2004. However, based on the changes in nutrient concentrations, phytoplankton production in the northwestern Gulf of St. Lawrence could have been somewhat lower in 2004 compared to 2003 but higher than for the 2000-2002 period. The mesozooplankton biomass observed in November in the LSLE and northwestern Gulf was lower than in 2003 and corresponded to the second lowest level of the last 10 years. However, the macrozooplankton biomass observed in 2004 was higher than in 2003. In 2004, the euphausiid biomass was the lowest of the last decade, and for the first time the mean biomass of the hyperiid amphipod Themisto libellula exceeded the mean euphausiid biomass. 3- General Environment Session: Seven papers were presented during the session. Among these was a paper reporting on a new device developed in Québec Region for in situ measurements and recording of dissolved O2 at depth. An example was shown of data collected during the Teleost 2004 summer survey in the Gulf of St. Lawrence. Fluctuations in oxygen saturation levels in bottom waters could have a significant influence on the distribution and condition of groundfish. Large-scale geographical trends and recent changes in species richness in regions of the Northwest Atlantic were presented. It would seem that fish (especially smallbodied species) and plankton biodiversity have increased in the recent years. Using CPR data, an analysis of the cycle of abundance (seasonality) of phytoplankton and zooplankton taxa on the Newfoundland Shelf has revealed that no trend can be detected through time, contrary to patterns revealed from a similar analysis in the North Sea, despite a similar range in temperature changes for the two environments. 4- Business meeting: At this years meeting, a larger proportion of time than usual was devoted to FOC business. In addition to reviewing and approving the regional Ecosystem Status Reports (ESRs), the committee (1) reviewed its Terms of Reference, (2) continued its discussion and agreed on a proposition for a definition of the respective roles of the AZMP and the FOC in regard to the preparation and presentation of the regional ESRs and on a new mode of operation to maintain the links between the two groups, (3) agreed on a proposal for a five-year work plan for the FOC, and (4) revised the list of current members and made recommendations for new regional representatives. Finally, the FOC agreed on the following Recommendations 1. Information from the summer Mackerel eggs survey and from the southern Gulf groundfish survey should be included in the Gulf of St. Lawrence physical oceanography review (ESR), and in future Chemical and Biological oceanographic conditions reports, the information corresponding to the entire Gulf should be merged into one document (as for Physical Oceanographic conditions); 2. An exercise should be initiated to compare seasonality between data and model outputs at some (AZMP) fixed stations (e.g., Shediac Valley) to find out how the model captures seasonal variability; 3. The AZMP is a more appropriate group for the preparation and presentation of the detailed regional environmental reviews and the production of the ESRs. However, the FOC needs information on the lower trophic levels and the physical environment to pursue its mandate, and it is essential to continue to have working links with the AZMP. Therefore, it is recommended to have successive but partly-overlapping three-day annual meetings of both the AZMP and the FOC, preferably at the end of March at a neutral location (e.g., Montréal); 4. The FOC will continue to function in an ad hoc manner so that issues (environmental, fisheries-related) that may arise unexpectedly will be dealt with as in the past, but it is proposed that the committee will focus its activities mainly on the upper trophic levels of the marine food web; 5. It was agreed to develop a proposal for a 5-year plan to gather and analyse data for the various components (e.g., species composition, abundance, physiological conditions of fish and invertebrates) necessary to describe the current and historical state of the continental shelf ecosystems in the Atlantic zone; 6. That it is necessary to bring to the FOC more scientists who are closer to ecosystem level and fisheries issues; 7. The FOC agreed on the suggestion that Dr. Michael Sinclair (Mar - BIO) should be offered the chairmanship.
DUTIL, J.-D., J. GAUTHIER, A. FRÉCHET, M. CASTONGUAY, Y. LAMBERT, P. OUELLET, 2005. Northern Gulf of St. Lawrence (NAFO 3Pn and 4RS). Pages 105-113 in K. Brander (ed.). Spawning and life history information for North Atlantic cod stocks. International Council for the Exploration of the Sea (ICES Coop. Res. Rep., 274) .
OUELLET, P., D. CHABOT, 2005. Rearing Pandalus borealis (Krøyer) larvae in the laboratory : I. Development and growth at three temperatures. Mar. Biol., 147(4): 869-880 .
Northern shrimp Pandalus borealis (Krøyer) larvae hatch in the northern Gulf of St. Lawrence from early May to the end of June, and larval development occurs over a range of relatively cold water temperatures. Because of the long duration of the pelagic phase and the difficulty of sampling all successive larval stages at sea, we used laboratory experiments to assess the effects of water temperature on larval development and growth. In spring 2000, P. borealis larvae were reared from hatching to the first juvenile stages (i.e., stage VI and VII) at three temperatures (3, 5, and 8 °C) representing conditions similar to those in spring in the northern Gulf of St. Lawrence. Larval development and growth were dependent on temperature, with longer duration and smaller size (cephalothorax length, CL , and dry mass, DM) at 3 °C relative to the 5 and 8 °C treatments. There were no significant differences in the morphological characters of the different stages among treatments, indicating that regular moults occurred at each temperature. The results suggest a negative impact of cold temperatures (lower intra-moult growth rates and smaller size) and, possibly, higher cumulative mortality due to longer development time that could affect the success of cohorts at sea. However, CL and DM for stage III and later larvae were smaller than those of larvae identified at the same developmental stage in field locations. It is possible that the diet offered to larvae in this experiment (Artemia nauplii, either newly hatched nauplii or live adults, depending on the developmental stage) was not optimal for growth, even though it is known to support successful P. borealis larval development. In the field, there is the possibility that phytoplankton contributes to the larval diet during the first stages and stimulates development of the digestive glands. Furthermore, the nutritional quality of the natural plankton diet (e.g., high protein content, fatty acid composition) might be superior and favourable to higher growth rates even at lower temperatures.©2005 Springer-Verlag
OUELLET, P., F. PLANTE, 2004. An investigation of the sources of variability in American lobster (Homarus americanus) eggs and larvae: female size and reporduction status, and interannual and interpopulation comparisons. J. Crust. Biol., 24(3): 481-495 .
From 1997 to 2001, the effects of female size (cephalothorax length [CL]) and reproductive status on egg size (diameter, dry weight) and larva CL at hatching were investigated in two Homarus americanus populations in the Gulf of St. Lawrence (Îles-de-la-Madeleine, Anticosti) and one at Grand Manan (Bay of Fundy), Canada. The estimated size at 50 % maturity was used to identify small (likely primiparous) females for each population. Multifactor, mixed-hierarchical ANOVA models were used to investigate the variability of eggs and stage I CL among years and populations. In all comparisons, the main source of variability in the egg and stage I larva size was females (within and among). Nevertheless, for the Îles-de-la-Madeleine population in each year except 2001, the mean stage I larva sizes from small (CL < 79 mm), probably primiparous females were significantly smaller (P < 0.0085) than the mean larva sizes from larger females. However, female CL per se explained very little of the variance in mean larval size at hatching (r2 = 0.23, P < 0.05 and r2 = 0.12, P = 0.22 in 2000 and 2001, respectively, when the entire size range of reproductive females was considered). Hatching larvae tend to be smaller in primiparous females or females maturing at a small size; however, over the entire size range of reproductive females, larval size at hatching is almost independent of female size (CL). It is as if, above a minimum viable size, there is a constant small range of egg/larval sizes produced in H. americanus. Conservation measures dealing with the imposition of a minimum legal size may be a means of increasing the number of females that will spawn at least once or twice within a population. However, the impacts of first-time spawning on quality of eggs and larvae need to be fully investigated to assess the response of the population's egg production and recruitment potential of this measure.
SIBERT, V., P. OUELLET, J.-C. BRÊTHES, 2004. Changes in yolk total proteins and lipid components and embryonic growth rates during lobster ( Homarus americanus) egg development under a simulated seasonal temperature cycle. Mar. Biol., 144: 1075-1086 .
From August 2000 to June 2001, seven eggcarrying female lobster (Homarus americanus) from the Iles de la Madeleine population (Gulf of St. Lawrence, Canada) were held under a simulated seasonal temperature cycle to monitor egg development from extrusion to hatching. For the first time, changes in the yolk components (total lipids and major lipid classes, total proteins) and embryo growth of single eggs were monitored separately over the entire development period. Under the controlled temperature conditions, egg development proceeded in three phases. (1) Autumn, from extrusion to early December, was marked by a rapid increase in the Perkinss eye index and rapid declines in yolk total proteins and triacylglycerols (TAG). Embryo daily growth rate was estimated between 1 and 2 μg proteins day)-1. (2) Winter, from late December to early April (temperature stable at ca. 1 °C) was characterized by a stationary phase in the evolution of the eye index and yolk lipid use, and embryo growth slowed significantly. (3) Spring, from late April to hatching in June was the period with the most rapid changes in yolk TAG and embryo growth rates >6 μlg proteins day-1 were recorded. Almost 65 % of the live biomass (total proteins) of the hatching larvae was accumulated during the last few weeks of development. An index of embryo growth efficiency was estimated as the slope of the relationship between embryo total proteins and yolk TAG during egg development. A relationship was found between the initial mean egg dry weight and the embryo growth efficiency index suggesting that under the same experimental conditions bigger eggs used yolk lipids more efficiently and sustained faster embryonic growth than smaller eggs. The relationship may also explain why larger larvae originate from larger eggs.©2004 Springer-Verlag
OUELLET, P., 2004. Final report of the Fisheries Oceanography Committee 2004 annual meeting : March 16-19, 2004, Battery Hotel, St. John's, Newfoundland-Labrador ; Rapport final de la réunion annuelle de 2004 du Comité sur l'océanographie des pêches : 16-19 mars 2004, Hotel Battery, St. John's, Terre-Neuve-Labrador. DFO, Canadian Science Advisory Secretariat, Proceedings Series ; MPO, Secrétariat canadien de consultation scientifique, Série des comptes rendus, 2004/019, 110 p .
The Fisheries Oceanography Committee of the Department of Fisheries and Oceans met in St. Johns, Newfoundland and Labrador, on 16-19 March 2004. The Committee reviewed environmental conditions in the Northwest Atlantic during 2003, convened a theme session on the current state of the pelagic ecosystems of the Atlantic Zone, reviewed additional papers on physical and biological oceanography, and conducted its annual business meeting. 1- Physical Environment in 2003: A large-scale cold anomaly of air temperatures over the eastern Arctic, Labrador, and the Labrador Sea was observed from February to April followed by two months of above normal temperatures. For the Gulf of St. Lawrence, Newfoundland, and Maritimes regions, air temperatures were colder-than-normal from January through April while they were slightly above normal in May and June. In terms of annual means, the anomalies were above normal because of the large warm anomalies (especially at the northern sites) for the second half of the year. The North Atlantic Oscillation index was below normal and nearly unchanged from 2002. Overall, although the period of ice presence was longer than normal, 2003 was a lighter-than-average ice year on the Labrador and Newfoundland shelves in terms of coverage. Within the Gulf of St. Lawrence, the maximum area of ice coverage rose relative to 2002 and previous years. On the Scotian Shelf, the January- May ice coverage was the third highest in the 42-year record. The largest positive annual sea-surface temperature (SST) anomaly was observed in the Labrador Sea (Bravo station); anomalies generally decreased along the Labrador Shelf to near zero on the northern Grand Bank. On the Scotian Shelf and in the Gulf of Maine, SSTs (January to June only) were below normal. Very cold surface conditions were observed during the winter in the Gulf of St. Lawrence, and it seems that these conditions were responsible for the major increase in the thickness of the summertime CIL and the decrease of its minimum temperature. The cross-sectional area of the CIL on the Newfoundland and Labrador Shelf increased slightly relative to 2002. The area of bottom water less than 0 °C increased on St. Pierre Bank in spring 2003. A very broad CIL and below-normal temperatures were recorded during the July groundfish survey on the Scotian Shelf. Cold bottom temperature is one important factor influencing groundfish distribution. 2- Biological Environment in 2003: The magnitude and duration of the spring bloom at Station 27 (Newfoundland) in 2003 was comparable to previous years. The overall zooplankton abundance was comparable to previous years; however, small copepod species (Oithona sp. Pseudocalanus sp.) dominated the community and appeared to be increasing on the northeastern Newfoundland Shelf. The most prominent feature of the phytoplankton in the Maritimes region in 2003 was the widespread and large spring bloom. In contrast, chlorophyll levels were lower in the southern Gulf relative to 2002 (however, chlorophyll levels were unusually high last year in the southern Gulf). The CPR data continue to show that contemporary phytoplankton levels are well above the long-term mean and that the seasonal cycle starts earlier relative to the 1960s and 1970s. In general, zooplankton levels increased at most sites but especially so in the southern Gulf, where record high abundances of Calanus finmarchicus were observed in 2003. The initiation of the major bloom at station Rimouski (St. Lawrence Estuary) occurred in late May, one month earlier than usual. Based on the nutrient evolution, phytoplankton production could have been higher in 2003 in the northwestern Gulf of St. Lawrence. Zooplankton biomass and abundance at the northern Gulf fixed stations were slightly higher in 2003 relative to the previous years. In the Lower Estuary and northwest Gulf, mesozooplankton biomass was slightly higher relative to 2002 while there was no change in the macrozooplankton biomass. 3- Recruitment: Indices of recruitment (R) and spawning stock biomass (SSB) for many exploited fish stocks have been compiled from research surveys conducted over the past 20+ years and incorporated into a common database for the northwest Atlantic. For many stocks, model-based estimates of R and SSB were also compiled and added to the database. Standardized anomalies of R, SSB, and recruitment rate (ln R/SSB) were presented to compare temporal trends among species and stocks. In general, there is a good agreement between the trends derived from research surveys and model estimates. Declining trends were evident in both R and SSB for most cod stocks, but R/SSB values were more variable. Herring R was variable among stocks with recent positive anomalies on the Scotian Shelf and Georges Bank. However, R/SSB anomalies were mostly positive among herring stocks, suggesting a future increase in herring SSB. Among flatfish, recent R and SSB anomalies were positive for southern stocks. A principal components analysis revealed (first axis for R) a sharp transition around the early 1990s that was interpreted as a shift from groundfish to pelagic dominance during that period. The general consensus among committee members was that the recruitment scorecard should be reviewed every few years to provide an overview on recent trends at the FOC meeting. 4- General Environment Session: Six papers were presented. The topics included the use of a physical model to estimate oceanic conditions in the southern Gulf and drift and survival of larval fish and invertebrate, the impact of water temperature variability on lobster egg development and larval size at hatching, and the exceptional mass mortality event of cod in Smith Sound (Newfoundland) in April 2003. 5- Theme Session: This years theme session, convened to examine the status of the pelagic ecosystems in the Atlantic Zone, was a great success, with 11 papers presented for discussion. There were really two main topics examined during the session: (1) phytoplankton and zooplankton production variability and (2) recent changes in the fish community in each region. In addition to large-scale and topdown events, local changes in mixing (nutrient availability), stratification, sea-ice dynamics, and phytoplankton assemblage (bottom-up effects) can explain a large proportion of the variability in the lower trophic levels. In the southern Gulf of St. Lawrence, the proportion of pelagic fish species in the total biomass increased from 25% in the early 1980 to 75% in the early 2000. However, reduced fishing pressure since the mid-1980s could explain this recent increase in abundance, especially for herring and mackerel. The abundance of pelagic fish may also have a negative impact on groundfish recruitment levels. Overall, it seems that we have seen a switch from the dominance of groundfish to pelagic species over the last 10 years, or more generally, a switch to small-bodied species (except in Newfoundland). It is not clear, however, if total pelagic biomass increased with the decline in groundfish biomass. Since the early 1990s, significant changes in capelin biology (distribution, spawning time, size, feeding) have been observed in the northwest Atlantic. It was suggested that large-scale oceanographic events (e.g., southward transport of Arctic water) may have affected capelin populations. 6- Business meeting: The session on the chemical and biological oceanographic conditions was followed by a long discussion on the need to present the data in a uniform format and for more integration and interpretation of the information. While everybody seemed to agree in principle, the debate continued on the means to achieve these goals. The participants discussed the role of the FOC as being the place where integration, comparisons of trends, and even simple modeling exercises could be initiated (with the implication that a review of the membership might be necessary). An adhoc group was formed to look at and make recommendations on possible ways to go from simple descriptions to presentations of integrative or systemic properties, even predictions at the meeting, and for the simplification of the regional Ecosystem Status Reports. No topic for next year Theme Session was agreed upon at the meeting. However, it was recommended and approved that the FOC should have a working session about integration, modelling and scales of variability, and to set a course for the next 5 years. Next years annual meeting was tentatively scheduled for late March 2005 in Moncton.
OUELLET, P., F. GRÉGOIRE, M. HARVEY, E. HEAD, B. MORIN, G. ROBERT, L. SAVARD, S. SMITH, M. STARR, D. SWAIN, 2003. Exceptional environmental conditions in 1999 in eastern Canadian waters and the possible consequences for some fish and invertebrate stocks. AZMP Bull. PMZA, 3: 21-27 .
[Abstract only available in French]
Plusieurs indicateurs des conditions atmosphériques indiquent que des températures de lair anormalement élevées en 1999 ont entraîné une réduction de la glace de mer en hiver et au printemps sur les plateaux continentaux de Terre-Neuve, du Labrador et de la Nouvelle-Écosse et une augmentation des températures de leau de surface sur lensemble de la zone Atlantique. Également, dautres indices indiquent que le cycle de production biologique (la floraison du phytoplancton) a été initié plus tôt en 1999 dans la plupart des régions de la zone. Ces conditions océanographiques exceptionnelles auraient eu des conséquences positives sur la production (ex. recrutement, croissance) de nombreux stocks de poissons et dinvertébrés dans lEst du Canada.
GENDRON, L., A.M. WEISE, M. FRECHETTE, P. OUELLET, C.W. McKINDSEY, L. GIRARD, 2003. Evaluation of the potential of cultured mussels (Mytilus edulis) to ingest state I lobster (Homarus americanus) larvae. Can. Ind. Rep. Fish. Aquat. Sci., 274, 20 p .
In Quebec, mussel aquaculture is expanding rapidly and is being developed in areas where lobster is present and where lobster larvae are likely to be found. Lobster fishermen are concerned that mussel aquaculture could pose a threat to lobster larvae. They believe that cultured mussels may ingest or otherwise kill lobster larvae. The objective of this study was to evaluate the potential of cultured mussels (Mytilus edulis) to ingest stage I lobster (Homarus americanus) larvae and, if this does occur, determine whether this ingestion kills or other wise harms the larvae.
GENDRON, L., A.M. WEISE, M. FRECHETTE, P. OUELLET, C.W. McKINDSEY, L. GIRARD, 2003. Évaluation du potentiel des moules délevage (Mytilus edulis) à ingérer des larves de homard (Homarus americanus) de stade I. Rapp. can. ind. sci. halieut. aquat., 274, 20 p .
In Quebec, mussel aquaculture is expanding rapidly and is being developed in areas where lobster is present and where lobster larvae are likely to be found. Lobster fishermen are concerned that mussel aquaculture could pose a threat to lobster larvae. They believe that cultured mussels may ingest or otherwise kill lobster larvae. The objective of this study was to evaluate the potential of cultured mussels (Mytilus edulis) to ingest stage I lobster (Homarus americanus) larvae and, if this does occur, determine whether this ingestion kills or other wise harms the larvae.
OUELLET, P., J.-P. ALLARD, 2002. Seasonal and interannual variability in larval lobster Homarus americanus size, growth and condition in the Magdalen Islands, southern Gulf of St. Lawrence. Mar. Ecol. Prog. Ser., 230: 241-251 .
OUELLET, P., D. LEFAIVRE, J.-P. ALLARD, 2001. Abondance des larves de homard (Homarus americanus) et disponibilité des post-larves pour l'établissement benthique aux Îles-de-la-Madeleine, sud du golfe du Saint-Laurent (Québec). Pages 17-21 in M.J. Tremblay & B. Sainte-Marie (eds.). Symposium sur le Programme intégré sur le homard canadien et son environnement (PINHCE): résumés et sommaire des travaux. Rapp. tech. can. sci. halieut. aquat., 2328, 130 p .
HARDING, G., K. DRINKWATER, J. LODER, C. HANNAH, P. VASS, P. OUELLET, J. SHORE, 2001. Distribution, variabilité et dispersion des larves de homard sur les bancs Browns et German et dans la région côtière du sud-ouest de la Nouvelle-Écosse: 1) distribution et écologie des larves. Pages 5-7 in M.J. Tremblay & B. Sainte-Marie (eds.). Symposium sur le Programme intégré sur le homard canadien et son environnement (PINHCE): résumés et sommaire des travaux. Rapp. tech. can. sci. halieut. aquat., 2328, 130 p .
OUELLET, P., D. LEFAIVRE, J.-P. ALLARD, 2001. Lobster (Homarus americanus) abundance and post-larvae availability to settlement at the Magdalen Islands, southern Gulf of St. Lawrence (Quebec). Pages 14-18 in Tremblay M.J. & B. Sainte-Marie (eds.). Canadian Lobster Atlantic Wide Studies (CLAWS) Symposium : abstract and proceedings summary. Can. Tech. Rep. Fish. Aquat. Sci., 2328, 130 p .
HARDING, G., K. DRINKWATER, J. LODER, C. HANNAH, P. VASS, P. OUELLET, J. SHORE, 2001. Larval lobster distribution, variability and dispersal in the Browns-German Banks and coastal southwest Nova Scotia region: (1) Larval distribution and ecology. Pages 3-5 in Tremblay M.J. & B. Sainte-Marie (eds.). Canadian Lobster Atlantic Wide Studies (CLAWS) Symposium : abstract and proceedings summary. Can. Tech. Rep. Fish. Aquat. Sci., 2328, 130 p .
LAMBERT, Y., J.-D. DUTIL, P. OUELLET, 2000. Nutritional condition and reproductive success in wild fish populations. Pages 77-84 in Norberg (ed.). Proceeding of the 6th international symposium on the reproductive physiology of fish, 4-9 July 1999 .
OUELLET, P., B. SAINTE-MARIE, 1998. Distribution et abondance des larves de homard (Homarus americanus) aux Îles-de-la-Madeleine : implications pour la disponibilité des postlarves et le succès de l'établissement benthique. Pages 109-115 in L. Gendron (éd.). Compte-rendu d'un atelier de travail sur l'ensemencement des stocks de homard, tenu aux Îles-de-la-Madeleine (Québec) du 29 au 31 octobre 1997. MPO (Rapp. Can. Ind. Sci. Halieut. Aquat., 244) .
OUELLET, P., B. SAINTE-MARIE, 1998. Distribution and abundance of lobster (Homarus americanus) larvae in the Magdalen Islands : implications for the availability of postlarvae and benthic settlement. Pages 101-107 in L. Gendron (ed.). Proceedings of a Workshop on Lobster Stock Enhancement held in the Magdalen Islands (Quebec) from October 29 to 31, 1997 . Dept. of Fisheries and Oceans (Can. Ind. Rep. Fish. Aquat. Sci., 244) .
DUTIL, J.-D., M. CASTONGUAY, M.O. HAMMILL, P. OUELLET, Y. LAMBERT, D. CHABOT, H. BROWMAN, D. GILBERT, A. FRÉCHET, J.-A. GAGNÉ, D. GASCON, L. SAVARD, 1998. Environmental influences on the productivity of cod stocks : some evidence for the northern Gulf of St. Lawrence, and required changes in management practices. DFO, Canadian Stock Assessment Secretariat, Research Document, 98/18, 42 p .
OUELLET, P., Y. LAMBERT, M. CASTONGUAY, 1997. Spawning of Atlantic cod (Gadus morhua L.) in the northern Gulf of St. Lawrence : a study of adult and egg distributions and characteristics. Can. J. Fish. Aquat. Sci., 54: 198-210 .
From 1993 to 1995, Atlantic cod (Gadus morhua) egg abundance and distribution, fisheries acoustic surveys, and analysis of trawl catches provided evidence of spawning for the northern Gulf of St. Lawrence cod stock at the same location off Newfoundland's west coast. From the relative proportion of spent fish and various developmental stages of cod eggs, spawning could not have started before the end of March or early April. Spawning started while cod were in dense shoals following a prespawning migration from Cabot Strait. Larger cod started to spawn earlier than smaller cod. In May 1994, cod dispersed soon after spawning began, and most of the spawning activity probably occurred as the fish migrated and scattered within the northern Gulf. Stage 1 cod eggs were distributed throughout the water column but higher concentrations were observed within the cold (<0 °C) layer of the Gulf each year. It is proposed that water temperature could have a dominant influence on determination of year-class strength in the northern Gulf via its effect on egg development and survival.
OUELLET, P., 1997. Characteristics and vertical distribution of Atlantic cod (Gadus morhua) eggs in the northern Gulf of St. Lawrence, and the possible effect of cold water temperature on recruitment. Can. J. Fish. Aquat. Sci., 54: 211-223 .
In early May from 1993 to 1995 the water column in the northern Gulf of St. Lawrence was weakly stratified, with cold water (< 2 °C) extending from ca. 125 m to the surface. Cod (Gadus morhua) eggs were distributed throughout the water column, but higher densities were observed in the cold intermediate layer. The vertical distribution of cod eggs was determined by egg size and organic (lipids, proteins) composition. Stage 1 egg density estimates in May 1994 ranged from 25.0 to 26.0 kg•m-3, which is higher than the water density of the upper mixed layer. Between 1980 and 1989, there was a weak positive relationship between the cold intermediate layer temperature anomalies and cod year-class strength (i.e., abundance of 3-year-old cod). It is unlikely that low recruitment levels caused by below-average temperature of the cold intermediate layer alone had a major impact on the recent collapse of the northern cod stock. The poor state of the spawning stock (low abundance, poor fish condition, and less bouyant eggs) and harsh late winter and early spring conditions in the northern Gulf can limit the potential for high recruitment and rapid recovery of the northern Gulf cod stock.
OUELLET, P., Y. LAMBERT, 1996. Maternal influence on Atlantic cod Gadus morhua egg characteristics and survival potential. 76th Annual Meeting of the American Society of Ichthyologists and Herpetologists, New Orleans, LA (USA), Jun 13-19 .
OUELLET, P., C.T. TAGGART, K.T. FRANK, 1995. Early growth, lipid composition, and survival expectations of shrimp Pandalus borealis larvae in the northern Gulf of St. Lawrence. Mar. Ecol. Prog. Ser., 126: 163-175 .
Respiration (physiological and enzymatic potential), growth (dry-weight [DW], body and carapace lengths), and protein content were measured on the larval stages of the northern shrimp Pandalus borealis. The relationship between oxygen consumption and growth through the larval development was examined under controlled laboratory conditions of temperature and food mixture. Body and carapace lengths, as well as respiration (R) increased as a linear function of time (days) during larval development, whereas biomass, measured as dry-weight and protein content, and enzymatic potential respiration (ETSA) are best described as exponential functions of time during the experiment. There was a decreasing trend in the weight-specific respiration rate (dry-weight-based, QO2) during development from hatching to the last larval instar. We estimate that the zoeae of P. borealis require a minimum of 2.95 to 0.44 J mg DW-1 d-1 from the zoeae I stage to the megalopa stage. We propose that the R/ETSA ratio could be used as a quantitative index of the sensitivity of shrimp larvae to environmental stress. The first larval instar would be the most vulnerable, since respiration is close to the respiratory capacity. With growth, and the decrease of the R/ETSA ratio, the later larval instars had a higher potential to generate energy and to respond to environmental stress.
OUELLET, P., D. LEFAIVRE, 1994. Vertical distribution of northern shrimp (Pandalus borealis) larvae in the Gulf of St. Lawrence; implications for trophic interactions and transport. Can. J. Fish. Aquat. Sci., 51: 123-132 .
OUELLET, P., J.-P. ALLARD, J.-F. ST-PIERRE, 1994. Distribution des larves d'invertébrés décapodes (Pandalidae, Majidae) et des oeufs et larves de poissons dans le nord du golfe du Saint-Laurent en mai et juin de 1985 à 1987 et 1991-1992. Rapp. tech. can. sci. halieut. aquat., 2019, 60 p .
From 1985 to 1987, and in 1991 and 1992, seven plankton surveys were conducted, between the end of April and early July in the northern gulf of S t. Lawrence. These missions provide informations on the species composition and the distribution of larvae of invertebrate decapods and of the eggs and larvae of fish species. A total of 28 species from 13 families (2 families of decapods and 11 fadies of fishes) were enumerated from these surveys. The larvae of the shrimp Pandalus spp. and crabs (Chionoecetes opilio andlor Hyas spp.) are the first to be found in large numbers in the northern Gulf. Moreover, the decapod larvae were always more abundant than the larval ichthyoplankton. The larvae of sandlances (Ammudytes spp.) and redfishes (Sebastes spp.) dominated the larval fish fauna. In May, in the northern Gulf, fish eggs were mostly represented by the eggs of the Atlantic cod (Gadus mrhua) and witch flounder (Glyptocephalus cynoglossus). The analysis of cod egg distribution from 1985 to 1987 revealed that there was simultaneous spawning events occuring in each sector, as soon as early-May, possibly from independent reproductive units of the northern Gulf cod population.
LOVRICH, G.A., P. OUELLET, 1994. Patterns of growth and triacylglycerol content in snow crab Chionoecetes opilio (Brachyura : Majidae) zoeal stages reared in the laboratory. Mar. Biol., 120(4): 585-591 .
OUELLET, P., C.T. TAGGART, K.T. FRANK, 1992. Lipid condition and survival in shrimp (Pandalus borealis) larvae. Can. J. Fish. Aquat. Sci., 49: 368-378 .
OUELLET, P., D. LEFAIVRE, V.G. KOUTITONSKY, 1990. Distribution of shrimp (Pandalus borealis) larvae and hydrographic pattern in the northern Gulf of St. Lawrence. Can. J. Fish. Aquat. Sci., 47: 2068-2078 .
OUELLET, P., 1987. Mackerel (Scomber scombrus) egg abundance in the southern Gulf of St. Lawrence from 1979 to 1986, and the use of the estimate for stock assessment. CAFSAC Res. Doc., 87/62, 40 p .
Mackerel egg surveys carried out in the southern Gulf of St. Lawrence from 1979 to 1986 have been analysed in an attempt to calculate seasonal egg production and its presicion, and to assess the possibility of using the data in estimating the size of the stock. For each station, for each cruise, the daily production was estimated from the corrected number of stage 1 eggs, i.e. the observed number of stage 1 eggs in the sample added to the number of dead or deformed eggs, and the duration of the stage, which is a function of the sea surface temperature, at the station. In order to obtain an estimate of the variance of the total egg production, a post-stratification of the survey area was realized using the mean density of stage 1 eggs at each station for the period from 1979 to 1986 as the stratification variable. Three strate corresponding to concentric zones of different egg densities were designed over the area. The square root transformation was used to normalize the data within the stratum. The estimation of the mean and the variance within the stratum. The estimation of the mean and the variance within the stratum. The estimation of the mean and the variance within the stratum and the estimators for the whole population, i.e. total number of eggs produced, the variance, and the confidence interval, were calculated according to the procedure outlined for a stratified sampling method. The total egg prodcution for the season was obtained by locating the median date of a cruise, which corresponds to the time of the daily egg production, in relation with the data of peak spawning. The daily egg production associated to the area under the reproduction curve located at the point of the mid-cruise data, was then extended to the total egg production, i.e. the total area under the curve within 2s of the spawning cycle. The results show an increasing trend in the annual production of mackerel eggs beginning in 1983. This increasing trend is also noted in other abundance indices of the stock.
OUELLET, P., 1987. Distribution automnale des stades larvaires de capelan (Mallotus villosus) et de hareng (Clupea harengus) dans le nord du golfe du Saint-Laurent en octobre 1985. Rapp. tech. can. sci. halieut. aquat., 1583, 27 p .
Sampling was accomplished in October 1985 in the northern Gulf of St. Lawrence to gather information on distribution of capelin and herring larvae. Analysis of demographic structure of capelin and herring larvae from the northern Gulf of St. Lawrence reveals a uniform spacing of emergence of distinct larval groups. Analysis of spatial distribution of capelin larval cohorts suggests the presence of zones of concentration in Mingan and Natashquan areas (North Shore of Quebec) and in an area southwest of Anticosti Island. Analysis of spatial distribution of herring larval cohorts revealed the importance of a coastal area east of Natashquan, as a spawning ground for herring groups in this region of the Gulf.
OUELLET, P., L. SAVARD, 1986. Évaluation des populations de crevettes (Pandalus borealis) des zones de pêche du golfe du Saint-Laurent. CSCPCA doc. rech., 86/19, 52 p .
For the entire Gulf of St. Lawrence, shrimp landings have increased by more than 1 300 t from 1984 to 1985 due to higher catches in the Sept-Îles and North Anticosti areas. Landings from the Sept-Îles area reached an all time high of 4 151 t in 1985, an increase of 5 % compared with 1984. Increased effort in 1985 (11 %) would explain this increase in catch as the catch rates are the same for the two years (68 kg/hr). The fall 1985 biomass survey gave the highest biomass estimate since the 1980 survey. The analysis of the population structure indicated relatively more important modal classes I and II compared to the previous year. All indices suggest that the shrimp population in the Sept-Îles area has been stable since 1980 and little change is anticipated for 1986. Landings in the North Anticosti area more than doubled between 1984 and 1985. Commercial catch rates were 100 kg/gr, the highest since 1982. Increased relative abundance of modal class III (already observed as abundant as modal class II in 1984) would explain these increased catch and catch rates for the last fishing season. The fall 1985 biomass estimate also increased compared with 1984, but proportially less than the commercial catch rates did. The analysis of the population structure showed average modal class II abundance but higher than usual abundance of modal class I. Indices of stock status suggest that catch rates should remain high in 1986. Landings for the Esquiman Channel area slightly lower in 1985 than in 1984. Problems with the commercial statistics prevented the calculation of a commercial catch rate reflective of stock status for 1985. However, the biomass estimate from research survey in the autumn of 1985 confirmed the 1984 results that indicated a decreased abundance for that population.
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