Bibliography of the Maurice Lamontagne Institute

Marcel FRÉCHETTE

FRÉCHETTE, M., 2012. Self-thinning, biodeposit production, and organic matter input to the bottom in mussel suspension culture. J. Sea Res., 67(1): 10-20 .

Future mussel suspension-culture methods may increasingly bypass standard population density adjustment on culture gear. This likely to exacerbate mussel fall-off. The potential extent of mussel fall-off is unknown. Here I use Dynamic Energy Budget theory and self-thinning theory to model the contribution of mussel fall-off to the total input of organic matter to the bottom. I focus on mussel populations grown on collector ropes and undergoing space-regulated self-thinning. Over a complete growth cycle, fall-off of mussel biomass was three times as high as the quantity harvested and accounted for 59 % of total input of organic matter to the bottom. Biomass fall-off with collectors was 6–30 fold higher than with sleeving methods, as estimated from the literature. The relative contribution of mussel fall-off increased in a step-like fashion with initial population density, indicating that either mussels or biodeposits may dominate the organic input to the bottom, unless year-to-year variability in spat abundance is very high. The relative contribution of mussel fall-off did not increase appreciably with the intensity of second-set, but total mussel fall-off did. Assessment of each input type to the bottom is required for forecasting the consequences of a shift in culture methods, as they have different, spatially structured, effects on benthic environments.©2011 Elsevier B.V.

FRECHETTE, M., M. LACHANCE-BERNARD, G. DAIGLE, 2010. Body size, population density and factors regulating suspension-cultured blue mussel (Mytilus spp.) populations. Aquat. Living Resour., 16: 339-346 .

We sampled 27 month-old mussel populations grown on collector ropes in Cascapédia Bay, Quebec, to test whether density-dependent growth was present concomitantly to self-thinning, a process which was previously shown to occur in this system and thought to be driven by spatial constraints. Biomass-density curves of raw samples were curvilinear, suggesting density-dependent growth. However, at least two cohorts were present. Fractionating the samples on the basis of age yielded a linear relationship for the main, 2 year-old cohort. This implies density-independent growth and rules out food regulation in these populations. Therefore, our results are consistent with inferences drawn previously from the values of the self-thinning exponent, that is, space-regulated self-thinning. Our results suggest that curvilinearity of the raw biomass-density curves resulted from a bias caused by including the 1 year-old cohort and spat of the year in the analysis. This conclusion is supported by a model showing that samples with mixed cohorts can yield linear, concave or convex biomass-density curves without density-dependent growth. The shape of the curves depends on the scaling relationships between cohort abundances. It appears that the shape of biomass-density curves may be a useful complementary criterion – in addition to the value of self-thinning exponents – for the identification of food or space as factors regulating cultured populations.

LACHANCE-BERNARD, M., G. DAIGLE, J.H. HIMMELMAN, M. FRÉCHETTE, 2010. Biomass–density relationships and self-thinning of Blue Mussels (Mytilus spp.) reared on self-regulated longlines. Aquaculture, 308: 34-43 .

We describe the population dynamics of mussels that are allowed to grow on collectors, and focus on selfthinning which determines the upper limit to yield. We studied two longlines at two farms in Baie de Cascapédia, Quebec, and sampled collectors chosen haphazardly on 22 occasions from October 2003 to July 2007. For each sampling date, three floats per longline were chosen. Each float supported a pair of collectors. Samples of 30.5-cm lengths were taken from collectors at two depths. In addition to biomass and population density, we monitored length–mass relationships, multilayering of mussels, proportions of collector lines where mussels had fallen off, depth of the lines and water temperature. The depth of the longlines appeared to vary with the biomass of the mussels attached to them. Although visual observation suggested that selfthinning occurred at farm 1, statistical tests were inconclusive (the models did not converge). Self-thinning occurred at farm 2 and a tridimensional model taking into account the number of mussel layers in addition to biomass and population density (Guiñez and Castilla, 1999; A tridimensional self-thinning model for multilayered intertidal mussels. Am. Nat. 154, 341-357) was more appropriate than a bidimensional model of self-thinning which takes into account biomass and population density only. This tridimensional model was developed for natural, flat substrates, but apparently is robust to physical situations encountered in mussel suspension culture. The tridimensional thinning exponents were not significantly different from –0.5, but were different or nearly different from –0.33, suggesting that self-thinning occurred because of lack of space. The documented self-thinning at farm 2 suggested that the carrying capacity of ropes had been attained. This implies that any increase in yield may only be achieved through improvement of the culture method.©2010 Elservier B.V.

FRÉCHETTE, M., 2010. Hierarchical structure of bivalve culture systems and optimal stocking density. Aquacult. Int., 18: 99-114 .

Bivalve culture systems are hierarchical, with culture units being nested within culture gear, which are nested within farms, and so on. The possibility that processes acting at the scale of individual culture units may interact with high-level processes has been overlooked in carrying capacity models, although basin-scale patterns are generated at the scale of culture units. Here I study the effect of increasing basin-scale loading on unit-scale optimal stocking density (OSD). I find a curvilinear relationship, with OSD decreasing with basin-scale loading. Clearly basin-scale models should incorporate culture-unit effects. This may be achieved by using experimental studies of the clearance rate of whole culture units to complement estimates of ecophysiological processes of individuals. Such culture-unit information, along with knowledge of associated local phytoplankton depletion at various current speeds and culture-unit stocking levels, may be used to generate submodels to be included in basin-scale models. To facilitate experimental testing of across-scale effects, I develop a simple food-regulated growth model combining density dependence at the scale of individual culture units and at the scale of basins.©2008 Her Majesty the Queen in Right of Canada

BILODEAU, F., M. LACHANCE-BERNARD, J.R. WILSON, M. FRÉCHETTE, 2008. Étude de la rentabilité de la production de moules sur collecteur autogéré à Carleton, Québec. Rapp. can. ind. sci. halieut. aquat., 282, 31 p .

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This work concerns a bioeconomic analysis of a new technique of growing mussels on collector lines. This technique, called self-regulating collectors, seeks to benefit from growing mussels in suspension while minimizing certain production costs. The technique consists in raising mussels directly from the structures used for the collection of spat. The lines are equipped with weights and buoys, which permit a more automatic regulation of the depth at which grow-out occurs, according to the mass of mussels. This allows the operator to save costs associated with stripping the collectors and placing the spat in sleeves. One possible drawback of the method is that there is a greater variability of sizes in the harvest and a slower growth rate, because the size of the spat and the density of the grow-out cannot be adjusted over time, as can be done with a sleeve technique. We examine results according to various criteria, such as profitability, size of mussels and limits on the productive capacity of the population. We studied two variants of the method. One technique (Technique A) uses buoys of 16 litres, and Technique B uses buoys of 40 liters. A third analysis (Technique C) is studied, where the grow-out is also completed on collectors of a more classic line technique. The “A” technique is studied on two sites. Measures using temperature and depth recorders made for technique A on one of the two sites indicate that the collectors performed as expected at the beginning of the study, but that they made contact at the bottom repeatedly towards the end of the trial period. Temperature shows a typical annual cycle, with large variations in summer. The “A” technique produces a total harvest of the order of 1,6 kg/30,5 cm of collector after 40 months of growth. Observed biomass is lower than potential biomass after the 15th month, what indicates that contacts with the bottom stripped collectors in all or in part from this time on. With the “B” technique, the total harvest is around 2,1 kg/30,5 cm of collector after 36 months, and we do not observe any stripping because of bottom contact. An economic breakeven point is reached at 2,2 kg/30,5 cm of collector for the “A” technique and at 2,1 kg/30,5 cm of collector for the “B” technique. Our analyses indicate that overpopulation and individual growth are not obstacles in obtaining profitability, because the self-thinning curve lies above the breakeven point. If there is an obstacle, it will be rather at the level of the performance of the lines: The “B” technique allows better flotation of the collectors and avoids stripping because of contact with the bottom. Trials of the “C” technique indicate that it is more profitable to proceed with sleeving than to leave the spat on the line, since a length of sleeve obtained from a collector's unit of length reaches a collector/sleeve ratio of 1: 1,31

TREMBLAY, I., M. FRÉCHETTE, J.-M. SÉVIGNY, H. E. GUDERLEY, 2007. Are bioenergetic properties linked with shell fluctuating asymmetry and heterozygosity in Iceland scallop, Chlamys islandica?. J. Shellfish Res., 26(1): 17-23 .

We investigated the relationship between physiological properties, swimming performance, shell fluctuating asymmetry, and heterozygosity at allozyme loci in the Iceland scallop, Chlamys islandica, in an attempt to describe potential physiological mechanisms for the negative relationship between shell fluctuating asymmetry and survival of this species in pearl nets (Fréchette & Daigle 2002). No clear relationship was observed between shell fluctuating asymmetry and the different physiological and genetic parameters, although the maximum number of contractions in a series during escape tests and the specific activity of arginine kinase in the adductor muscle were linked with shell asymmetry before the application of corrections for multiple comparisons. Pyruvate kinase activity in soft tissues was higher in animals that were heterozygous at 2 loci compared with those that were heterozygous at 4 loci. Although our exploratory study suggests that shell asymmetry may reflect bioenergetic difficulties, further study is required to confirm such links. ©2007 National Shellfisheries Association

TREMBLAY, I., H.E. GUDERLEY, M. FRÉCHETTE, 2006. Swimming performance, metabolic rates, and their correlates in the Iceland scallop Chlamys islandica. Physiol. Biochem. Zool., 79(6): 1046-1057 .

The dramatic escape response of some scallops is modified by reproductive investment and by acclimation temperature. Despite considerable knowledge of the physiology of the escape response, functional links between escape response performance, organismal rates of oxygen uptake, and tissue metabolic capacities are little known. We measured oxygen consumption rates (standard, maximal, and aerobic scope), escape behavior (initial and repeat performance), tissue mass, condition index, protein content, and tissue metabolic capacities in the Iceland scallop Chlamys islandica to examine links between these parameters. Postexercise oxygen consumption rates were positively linked to contraction rate (repeat test) and to pyruvate kinase activity in the adductor muscle but negatively linked to digestive gland wet mass. Swimming behavior was mainly related to activity of glycolytic enzymes, and enzymatic activities were related to anatomic parameters. Scallop behavior and physiology change with size, both within our samples and on a larger scale. Small scallops showed more intense swimming activity and had higher arginine kinase activities but lower glycolytic enzyme activities in their adductor muscle than larger scallops. This corresponds to the ontogenetic change in susceptibility to predation and in habitat use observed in C. islandica.©2006 The University of Chicago

FRECHETTE, M., M. ALUNNO-BRUSCIA, J.-F. DUMAIS, R. SIROIS, G. DAIGLE, 2005. Incompleteness and statistical uncertainty in competition / stocking experiments. Aquaculture, 246(1-4): 209-225 .

In competition experiments, decisions are made not only about experimental conditions such as initial population densities, of course, but also about population size structure, for instance. Here we use an individual-based simulation model to study the effect of size-grading of mussels. With low individual variability, predicted yield was lower and less variable, there was no density-dependent mortality, and optimal stocking density for aquaculture was lower than with high individual variability, whereby self-thinning occurred and yield was quite variable. Thus, individual variability was a critical factor for estimating survival effects of overstocking, at the expense of precision of growth estimates. Therefore, competition experiments are inherently incomplete. We argue that in practice, incompleteness cannot be overcome by using genetic information as a covariate because evidence from the literature shows that the effect of genetic makeup in competition situations is frequency-dependent. Apparently, the only approach presently available to obtain unbiased estimates is to use a size structure similar to that of the population under study. This contrasts with a literature review of bivalve stocking experiments published in Aquaculture through the last 30 years which clearly shows that the issue of size structure of test populations has been largely overlooked. The same principles hold for competition studies in natural settings.©2005 Elsevier B.V.

FRECHETTE, M., 2005. A comment on the methodology of stocking experiments. Aquaculture, 250(1-2): 291-299 .

Stocking density can have an important influence on the success of aquaculture operations. However, various aspects of the methodology of published experiments on stocking density appear problematical. For example, size variation in the system under study may have determinant effects on yield, survivorship and estimates of the optimal stocking density. To document whether this might be a source of concern in scientific advice to aquaculturists, I reviewed all stocking experiments published in Vol. 1 through Vol. 224 of Aquaculture and checked whether information about size variation had been reported in sufficient detail, whether size-sorting had occurred and whether groups of experimental individuals and cultured individuals had similar size variability. This was done for experiments on crustaceans and finfish (the corresponding analysis for bivalves is presented in Fre´chette et al. (2005) [Fre´chette, M., Alunno-Bruscia, M., Dumais, J.-F., Daigle, G., Sirois, R., 2005. Incompleteness and statistical uncertainty in competition/stocking experiments. Aquaculture 246, 209-225]). The analysis clearly shows that the issue of size variability of test cage populations has been largely overlooked in a large proportion of experiments. The study raised other sources of concern. For instance, allometry was overlooked in a significant proportion of experiments on crustaceans (55 %) and finfish (25 %), which caused ration level to be adjusted following inappropriate principles. The issues of replacement/removal of individuals and of the dimensions of the variable used to measure stocking level were also examined. Inappropriate procedures were found in a number of cases. Suggestions are made to deal with these issues in a more acceptable way. These problems, which may lead to serious flaws in advice to growers, were not restricted to papers published in Aquaculture.©2005 Elsevier B.V.

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 .

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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 d’élevage (Mytilus edulis) à ingérer des larves de homard (Homarus americanus) de stade I. Rapp. can. ind. sci. halieut. aquat., 274, 20 p .

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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.

FRÉCHETTE, M., P. GOULLETQUER, G. DAIGLE, 2003. Fluctuating asymmetry and mortality in cultured oysters (Crassostrea gigas) in Marennes-Oléron basin. Aquat. Living Resour., 16: 339-346 .

FRÉCHETTE, M., G. DAIGLE, 2002. Reduced growth of Iceland scallops Chlamys islandica (O.F. Müller) cultured near the bottom : a modelling study of alternative hypotheses. J. Shellfish Res., 21:87-91 .

FRÉCHETTE, M., G. DAIGLE, 2002. Growth, survival and fluctuating asymmetry of Iceland scallops in a test of density-dependent growth in a natural bed. J. Exp. Mar. Biol. Ecol., 270: 73-91 .

ALUNNO-BRUSCIA, M., E. BOURGET, M. FRÉCHETTE, 2001. Shell allometry and length-mass-density relationship for Mytilus edulis in an experimental food-regulated situation. Mar. Ecol. Prog. Ser., 219: 177-188 .

FRÉCHETTE, M., 2000. L'effet des dragues à pétoncles sur l'environnement marin. Naturaliste can., 124(1): 64-65 .

ALUNNO-BRUSCIA, M., P.S. PETRAITIS, E. BOURGET, M. FRÉCHETTE, 2000. Body size-density relationship for Mytilus edulis in an experimental food-regulated situation. Oikos, 90: 28-42 .

FRÉCHETTE, M., M. GAUDET, S. VIGNEAU, 2000. Estimating optimal population density for intermediate culture of scallops in spat collector bags. Aquaculture, 183: 105-124 .

FRÉCHETTE, M., M. GIGUÈRE, G. DAIGLE, 2000. Étude de l'effet du site d'élevage et de la provenance des spécimens sur le potentiel aquicole du pétoncle d'Islande Chlamys islandica (O.F. Müller) en Côte-Nord. Rapp. can. ind. sci. halieut. aquat., 258, 25 p .

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In order to supplement scallop fishery landings in the Mingan region, a number of culture and wild bed management strategies are presently under consideration. One such strategy implies transferring individuals from slow-growth donor sites to fast-growth culture sites. Knowledge about factors responsible for slow growth is necessary to evaluate the chances that relaying operations are successful and profitable. If slow growth were attributable to intrinsic characteristics of individuals (stock effect), such individuals would be of limited value for aquaculture operations. On the other hand, if slow growth were attributable to site effects, knowing whether slow growth results from intrinsically poor general environmental conditions or from overpopulation would be of interest because overpopulation would imply that not all animals would have to be transferred. Growth of individuals remaining on the donor sites would increase after culling. In addition to promoting growth, this would reduce transfer costs. Here we report experiments aimed at testing these possibilities. We made two experiments. The first one was a stock-site experiment. Scallops wer transferred from three donor sites located near île à la Proie (fast growth site), île Sainte-Geneviève and Baie-Johan-Beetz (both slow growth sites) to the site located mear île à la Proie. Controls from each site were grown without being transferred. Such transfers allow to test the relative contribution of stock and stie to variability in growth and survival. Some of grous could not be recovered. The experiment lasted two years. After the first year, individuals from île à la Proie had higher growth than those from the other stocks tested, and individuals from île Sainte-Geneviève grew faster near île à la Proie than near île Sainte-Geneviève. The goal of the secon experiment was to test for overpopulation on a slow-growth site. Scallops were installed in two sites, one populated with scallops, but not the other. On each site, some scallops were installed near the bottom while others were installed far from the bottom. With this set-up, all groups except that one near the bottom in the populated site were free from potential overpopulation effects. Our results are consistent with the hypothesis of no overpopulation in the populated site. On both sites, growth rate was smaller near the bottom, presumably because of higher density or resuspended inorganic particles near the bottom. Computer simulations, however, suggest that depth-related differences in current speed may also provide an explanation to lower growth near the bottom either through direct effects of current speed on scallop clearance rate or through indirect iffects on food replenishment rate within the pearl nets. Our results also suggest that the symmetry of the ears of the shell in the left-right symmetry axis (upper shell-lower shell) was a proxy for survivorship.

CLICHE, G., M. GIGUÈRE, P.-A. JONCAS, B. THOMAS, S. VIGNEAU, 1999. Programme de recherche sur le pétoncle à des fins d'élevage et de repeuplement : phase II. Ministère de l'agriculture, des pêcheries et de l'alimentation (Direction générale des pêches et de l'aquiculture commerciales. Direction de l'innovation et des technologies), 17 p .

FRÉCHETTE, M., E. DESPLAND, 1999. Impaired shell gaping and food depletion as mechanisms of asymmetric competition in mussels. Ecoscience, 6(1): 1-11 .

FRÉCHETTE, M., C. BACHER, 1998. A modelling study of optimal stocking density of mussel populations kept in experimental tanks. J. Exp. Mar. Biol. Ecol., 219: 241-255 .

FRÉCHETTE, M., P. BERGERON, P. GAGNON, 1996. On the use of self-thinning relationships in stocking experiments. Aquaculture, 145: 91-112 .

POULIOT, F., E. BOURGET, M. FRÉCHETTE, 1995. Optimizing the design of giant scallop (Placopecten magellanicus) spat collectors : field experiments. Mar. Biol., 123: 277-284 .

FRÉCHETTE, M., D. LEFAIVRE, 1995. On self-thinning in animals. Oikos, 73: 425-428 .

GIGUÈRE, M., M. FRÉCHETTE, 1994. Scallops on the Québec coast (areas 15, 16, 17, 18, 19 and 20). Pages 40-70 in L. Savard (ed.). Status report in invertebrates 1993 : crustaceans and molluscs on the Québec coast and northern shrimp in the Estuary and Gulf of St. Lawrence. DFO (Can. Manuscr. Rep. Fish. Aquat. Sci., 2257) .

FRÉCHETTE, M., L. PAGÉ, P. BERGERON, 1994. Vers un nouvel outil de gestion en aquiculture ; Toward a new management tool for aquaculture. Rapp. Can. Ind. Sci. Halieut. Aquat. ; Can. Ind. Rep. Fish. Aquat. Sci., 221, 19 p .

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We present a method for managing cultured mollusc populations, following principles presently in use in forestry and sylviculture sciences. This method is based on the analysis of the relationship between yield (biomass, B) and population density (N), from which one derives what is called a B-N diagram. Therefore the method relies essentially on experimental results. It is useful in helping to assess correct seeding density and when applicable, assessing the nature of the factor responsible for overpopulation. We give different ways are given of obtaining a B-N diagram, how to interpret it, and present a simple example of its use, using the blue mussel as an example organism. The B-N diagram is applicable, however, to other molluscs, fish, algae, and perhaps crustaceans. We suggest that in studies of correct seeding density, a wide range of densities be studied, even those which are known beforehand to be inadequate. Results of preliminary experiments made in the lagoon of Grande-Entrée, Îles-de-la-Madeleine, show that after a 54-week growth period, correct seeding density ranges somewhere between lower and upper limits of about 125 and about 175 mussels per foot of sock. About 50 % of individuals had reached the 50 mm commercial size. Had commercial size been smaller, the density boundaries would have been higher. The method may also prove useful in assessing the potential of a given site for enhancement.

BUTMAN, C.A., M. FRÉCHETTE, W.R. GEYER, 1994. Flume experiments on food supply to the blue mussel Mytilus edulis L. as a function of boundary-layer flow. Limnol. Oceanogr., 39: 1755-1768 .

A two-dimensional, advection-diffusion model of phytoplankton depletion above an assemblage of suspension feeders was tested in a laboratory flume containing a 6.1-m-long bed of the blue mussel Mytilus edulis L. Flows with near-surface velocities of similar to 5 and 15 cm s^-1 were tested in three experiments. Phytoplankton concentrations (as estimated by fluorescence) were measured just up-stream of and near the end of the mussel bed. Vertical profiles of velocity indicated that turbulent stress, and thus turbulent mixing, were three (slow flow) to ten (fast flow) times higher over the mussel bed compared to the smooth flume bottom. In two experiments that used natural seawater, initial fluorescence was low and there was little temporal depletion at either flow speed. In the one experiment in which cultured phytoplankton were added to filtered seawater so that initial fluorescence was much higher, significant vertical and substantial horizontal gradients in fluorescence developed. In this experiment, depletion was enhanced in slow flow compared to fast flow in both the downstream and vertical directions, as qualitatively predicted by the model. Furthermore, with a flow-speed-dependent mussel filtration velocity, modeled vertical profiles of fluorescence were consistent with the observations.©1994 American Society of Limnology and Oceanography, Inc.

GIGUÈRE, M., M. FRÉCHETTE, 1994. Pétoncle des côtes du Québec (zones 15, 16, 17, 18, 19 et 20). Pages 46-80 in L. Savard (éd.). Rapport sur l'état des invertébrés en 1993 : crustacés et mollusques des côtes du Québec et crevette nordique de l'estuaire et du golfe du Saint-Laurent. MPO (Rapp. manus. can. sci. halieut. aquat., 2257) .

BASTIEN, Y., G. CLICHE, M. FRÉCHETTE, M. GAUDET, M. GIGUÈRE, 1993. Bottom culture and enhancement : large-scale scallop enhancement trials in Québec - a synopsis of the REPERE project. Bull. Aquac. Assoc. Can., 93(4): 149-152 .

FRÉCHETTE, M., D. LEFAIVRE, C.A. BUTMAN, 1993. Bivalve feeding and the benthic boundary layer. Pages 325-369 in R.F. Dame (ed.). Bivalve filter feeders in estuarine and coastal ecosystem processes. Springer-Verlag .

FRÉCHETTE, M., A.E. AITKEN, L. PAGÉ, 1992. Interdependence of food and space limitation of a benthic suspension feeder : consequences for self-thinning relationships. Mar. Ecol. Prog. Ser., 83: 55-62 .

BÉRARD, H., E. BOURGET, M. FRÉCHETTE, 1992. Mollusk shell growth : external microgrowth ridge formation is uncoupled to environmental factors in Mytilus edulis. Can. J. Fish. Aquat. Sci., 49: 1163-1170 .

SCARRAT, D.J., C. MARTIN, T. de FREITAS, M. HAWRYLUK, M. DESBIENS, H. CHEBIB, S. DEMERS, M. FRÉCHETTE, D. BAUDINET, D.J. WILDISH, S.T. DUNCAN, W.W. YOUNG-LAI, T.J. SOMERSET, E. TODD, L. GODBOUT, 1992. Transfer of phycotoxins in the benthic food web. Pages 67-71 in J.-C. Therriault & M. Levasseur (ed.). Proceedings of the Third Canadian Workshop on Harmful Marine Algae, Maurice-Lamontagne lnstitute, Mont-Joli, Québec, 12-14 May, 1992 .

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ENNIS, J., K. DRINKWATER, P. OUELLET, P. BRUNEL, M. FRÉCHETTE, D. GAUTHIER, L. GENDRON, J. HIMMELMAN, C. HUDON, I. McQUINN, L. SAVARD, J. WORMS, 1991. Report of the Workshop on Invertebrates. Pages 47-54 in J.-C. Therriault (ed.). The Gulf of St. Lawrence : small ocean or big estuary ? Dept. of Fisheries and Oceans (Can. Spec. Publ. Fish. Aquat. Sci., 113) .

FRÉCHETTE, M., J. GRANT, 1991. An in situ estimation of the effect of wind-driven resuspension on the growth of the mussel Mytilus edulis L.. J. Exp. Mar. Biol. Ecol., 148: 201-213 .

BASTIEN, Y., G. CLICHE, M. FRÉCHETTE, M. GAUDET, M. GIGUÈRE, A. LONGUÉPÉE, 1991. REPERE : recherche sur le pétoncle à des fins d'élevage et de repeuplement. MAPAQ, DRST, Doc. trav., 91/03, 12 p .

ENNIS, J., K. DRINKWATER, P. OUELLET, P. BRUNEL, M. FRÉCHETTE, D. GAUTHIER, L. GENDRON, J. HIMMELMAN, C. HUDON, I. McQUINN, L. SAVARD, J. WORMS, 1991. Rapport de l'atelier de travail sur les invertébrés. Pages 47-54 in J.-C. Therriault (éd.). Le golfe du Saint-Laurent : petit océan ou grand estuaire? Ministère des pêches et des océans (Publ. spéc. can. sci. halieut. aquat., 113) .

FRÉCHETTE, M., 1991. Carrying capacity and density dependence (workshop report). ICES Mar. Sci. Symp., 192: 78 .

FRÉCHETTE, M., D.A. BOOTH, B. MYRAND, H. BÉRARD, 1991. Variability and transport of organic seston near a mussel aquaculture site. ICES Mar. Sci. Symp., 192: 24-32 .

FRÉCHETTE, M., D. LEFAIVRE, 1990. Discriminating between food and space limitation in benthic suspension feeders using self-thinning relationships. Mar. Ecol. Prog. Ser., 65: 15-23 .

BERGERON, P., M. FRÉCHETTE, L. PAGÉ, Y. LAVERGNE, G. WALSH, 1990. Sédimentation et dispersion des déblais de dragage en mer et effets sur la moule bleue (Mytilus edulis) en élevage dans la baie des Chaleurs. Rapp. tech. can. sci. halieut. aquat., 1746, 59 p .

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Dredging operations conducted along the wharf in Carleton and Saint-Godefroi yielded respectively a total of 1,903 and 3,660 m³ of deposits. This material was dumped offshore approximately 2,5 nautical miles from the coast and its dispersal was monitored with an echosounder and a transmissometer along compass courses radiating from the dumping site. Water transparency was analyzed along with data collected on grain-size frequency distribution, current speed and direction in order to estimate dispersal rates and sediment motions. A maximal reduction of 47,2 % of initial water transparency was recorded within 50 m of the dumping site. The coarse-grained fraction of the sediments sinked within one to three minutes close to the dumping site. Sediment dispersal was generally unidirectional and the size of the plume estimated with sounder echoes was below 20 m in diameter. Reduction of water transparency droped to 5-15 % of pre-dredging values 0,75 nautical mile from the source indicating that near complete dispersal and deposition of particulates were achieved within approximately 1 mile in the direction of prevailing currents. Results do not indicate any immediatly or long term effects (3 months) of the presence of dredged sediments on filtration rates, growth and mortality of transplanted cultured mussels. High sinking rate and limited dispersal of dredged material along with the net water movement during dumping activities however suggest that mussels may not have experienced high loads of suspended material during the study.

FRÉCHETTE, M., C.A. BUTMAN, W.R. GEYER, 1989. The importance of boundary-layer flows in supplying phytoplankton to the benthic suspension feeder, Mytilus edulis L.. Limnol. Oceanogr., 34: 19-36 .

FRÉCHETTE, M., 1989. Effet de l'orientation au courant sur la croissance du pétoncle géant, Placopecten magellanicus (Gmelin). Naturaliste can., 116: 79-85 .

FRÉCHETTE, M., E. BOURGET, 1987. Significance of small-scale spatio-temporal heterogeneity in phytoplankton abundance for energy flow in Mytilus edulis. Mar. Biol., 94: 231-240 .

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A review of the Quebec scallop landings since the beginning of the fishery was undertaken. Quebec catches in 1985 reached 129 t (meat weight), a 3% decrease relative to the 1984 catches. Catches from the Gaspesie, North Shore and Magdalen Islands regions were 12, 37 and 51 % of the total, respectively. For the Magdalen Islands, the decrease in the abundance indices, the results of a production model derived from the Leslie method and the yield-per-recruit analysis, all indicated that the stock was overexploited. North shore catch rates and the population structure showed that this fishery could maintain present levels in Sept-Îles and the Lower North shore areas but should be reduced in the Mingan area where the scallop population is older. Gaspesie landings should remain stable if the fishing effort stays at the same level.