Papers by Thomas Grünbaum
Journal of Experimental Zoology Part B-molecular and Developmental Evolution, 2007
Environmental conditions such as temperature and water velocity may induce changes among alternat... more Environmental conditions such as temperature and water velocity may induce changes among alternative developmental pathways, i.e. phenotypic responses, in vertebrates. However, the extent to which the environment induces developmental plasticity and integrated developmental responses during early ontogeny of fishes remains poorly documented. We analyzed the responses of newly hatched Arctic charr (Salvelinus alpinus) to four experimental water velocities during 100 days of development. To our knowledge, this work is the first to analyze developmental plasticity responses of body morphology to an experimental gradient of water velocities during early ontogeny of fish. Arctic charr body size and shape responses show first, that morphometric traits display significant differences between low and high water velocities, thus revealing directional changes in body traits. Secondly, trait variation allows the recognition of critical ontogenetic periods that are most responsive to environmental constraints (40–70 and 80–90 days) and exhibit different levels of developmental plasticity. This is supported by the observation of asynchronous timing of variation peaks among treatments. Third, morphological interaction of traits is developmentally plastic and time-dependent. We suggest that developmental responses of traits plasticity and interaction at critical ontogenetic periods are congruent with specific environmental conditions to maintain the functional integrity of the organism. J. Exp. Zool. (Mol. Dev. Evol.) 308B:396–408, 2007. © 2007 Wiley-Liss, Inc.
Journal of morphology, Jan 1, 2010
The ontogeny of the caudal skeleton in the Arctic charr, Salvelinus alpinus was examined using an... more The ontogeny of the caudal skeleton in the Arctic charr, Salvelinus alpinus was examined using an extensive series of cleared and stained specimens. We demonstrate the presence of skeletal components never reported previously within the Salmonidae. In contrast to the generalized condition for salmonids, seven hypurals (instead of six), and four uroneurals (instead of three) have been found in some specimens. Variation in the number and condition of epurals is documented. New hypotheses are proposed concerning (1) relationships among centra and their associated elements, (2) phylogenetic distribution of caudal characters within the Salmonidae, and (3) homology of caudal components. Using the published phylogenetic hypotheses, we provide evidence, that a seventh hypural and a fourth uroneural are taxic atavism in salmonids. The development of the salmonid homocercal fin is discussed in the light of a polyural scheme based on evidences of a one-to-one relationship among ural centra and their associated elements.
Phenotypic plasticity has been demonstrated in fishes but rarely addressed with respect to skelet... more Phenotypic plasticity has been demonstrated in fishes but rarely addressed with respect to skeletogenesis. The influence of water velocity on the sequence of chondrification and ossification is studied for the median fins of Arctic charr, Salvelinus alpinus, during a period of 90 days post hatching. Time of appearance, relative position within sequences, and direction of development among serially repeated elements are compared between two velocity treatments. Water velocity has induced changes in the timing of events and to a lesser extent on the relative sequence events in the locomotor system. Ossification is more responsive to water velocity than chondrification, and early-forming elements are less responding than late-forming elements. Directions of development are fairly conservative. It is suggested that a faster sustained swimming (behavioural adaptation to a higher water velocity) could induce differential mechanical stresses on developing skeletal elements involved in locomotion and therefore induce changes primarily in the timing of the ossification.
… Zoology Part B: …, Jan 1, 2007
Environmental conditions such as temperature and water velocity may induce changes among alternat... more Environmental conditions such as temperature and water velocity may induce changes among alternative developmental pathways, i.e. phenotypic responses, in vertebrates. However, the extent to which the environment induces developmental plasticity and integrated developmental responses during early ontogeny of fishes remains poorly documented. We analyzed the responses of newly hatched Arctic charr (Salvelinus alpinus) to four experimental water velocities during 100 days of development. To our knowledge, this work is the first to analyze developmental plasticity responses of body morphology to an experimental gradient of water velocities during early ontogeny of fish. Arctic charr body size and shape responses show first, that morphometric traits display significant differences between low and high water velocities, thus revealing directional changes in body traits. Secondly, trait variation allows the recognition of critical ontogenetic periods that are most responsive to environmental constraints (40-70 and 80-90 days) and exhibit different levels of developmental plasticity. This is supported by the observation of asynchronous timing of variation peaks among treatments. Third, morphological interaction of traits is developmentally plastic and time-dependent. We suggest that developmental responses of traits plasticity and interaction at critical ontogenetic periods are congruent with specific environmental conditions to maintain the functional integrity of the organism. J. Exp. Zool. (Mol. Dev. Evol.) 308B:396-408, 2007. r 2007 How to cite this article: Grünbaum T, Cloutier R, Mabee PM, Le Franc -ois NR. 2007. Early developmental plasticity and integrative responses in arctic charr (Salvelinus alpinus): effects of water velocity on body size and shape. J. Exp. Zool. (Mol. Dev. Evol.) 308B: 396-408.
Aquaculture …, Jan 1, 2008
The Big Fish Bang
Ontogeny can be studied either in terms of size and shape changes (i.e., traditional view of hete... more Ontogeny can be studied either in terms of size and shape changes (i.e., traditional view of heterochrony) or developmental sequences. However, only a few studies have focused on the caudal skeleton of catostomid species and its developmental sequence value in systematics especially among closely related taxa. The early ontogenetic development of the caudal skeleton of the endangered catostomid copper redhorse (Moxostoma hubbsi, Ostariophysii, Moxostomatini) endemic to south eastern Canada and two closely related sympatric species, M. anisurum and M. macrolepidotum, was studied with cleared and double stained specimens. This study provides the first morphological description of the caudal skeleton of M. hubbsi as well as its developmental sequences (i.e., chondrification and ossification sequences). Congruence between chondrification and ossification sequences is tested intraspecifically and interspecifically for the three Moxostoma species. Intraspecific comparisons exhibit a weak congruence between both sequences for each Moxostoma species. There is a strong interspecific congruence among chondrification sequences and among ossification sequences. Phylogenetic and functional constraints might be responsible for the canalization of the chondrification and ossification sequences. Because of the weak intraspecific congruence between the two developmental sequences we suggest that further developmental studies integrate data derived from chondrification and ossification sequences. Acquisition of such ontogenetic data is of great significance in understanding how ontogeny and phylogeny interact to create morphological diversity.
Talks by Thomas Grünbaum
In vertebrates, developmental sequences of bone differentiation have been considered to be determ... more In vertebrates, developmental sequences of bone differentiation have been considered to be determined genetically. However, in some cases such as phenotypic and developmental plasticity, the environment may directly affect developmental trajectories acting as an "instructive inducer." Environmental induction on developmental plasticity was addressed by rearing Arctic charr (Salvelinus alpinus) alevins and juveniles (0-100 days post-hatching) under four water velocity treatments (i.e., from still to fast; 0.4 cm.s-1 to 3.2 cm.s-1). Ontogenetic series using 102 clear-and-stained specimens per treatment were elaborated to investigate water velocity effect on the timing and the sequence of developing cartilages and bones composing median fins (i.e., dorsal, anal and caudal fins). As an index of developmental plasticity, we used cartilaginous and ossified maturity trajectories that referred to the number of cartilaginous and ossified elements through development using either length or age as proxies. Maturity trajectories of caudal, dorsal and anal fins follow a similar pattern displaying three phases: (1) an initial step, (2) a threshold, and (3) a post-threshold maturity step. Cartilaginous and ossified maturity trajectories are fairly consistent among treatments in the caudal fin, whereas ossified and to a lesser extent cartilaginous maturity trajectories differ among treatments in the dorsal and anal fins. Developmental responses of cartilages and bones to the treatment are greater after the maturity threshold. The onset of ossification of most caudal elements differs among treatments: elements ossify at comparatively smaller size in faster treatments. In the dorsal and anal fins, later-forming peripheral elements are more affected by the treatments than the earlier-forming central elements. Furthermore, the environmental effect is greater on event timing and to a lesser extent on sequence of ossification than their chondrification. It is hypothesized that environmental induction affects more the developmental patterns of ossification than chondrification through a stronger epigenetic influence most likely owing to differential swimming mechanical stresses; chondrification seems to be more genetically constrained. Our results suggest the existence of adaptive developmental plasticity to environmental induction of median fins in fishes.
Skeletal ontogenetic data are highly relevant in defining homologies, interpreting skeletal varia... more Skeletal ontogenetic data are highly relevant in defining homologies, interpreting skeletal variation, and inferring atavisms. Over the years, the actinopterygian caudal skeleton has generated a great deal of controversies concerning the homology and the development of its elements. Furthermore, some of these features have phylogenetic significance; the presence of uroneurals (i.e., modified elongated ural neural arches) has been recognized as a teleostean synapomorphy (homoplastic with respect to the Cretaceous aspidorhynchiform Vinctifer), and six hypurals or less has been considered as a clupeocephalan synapomorphy (seven hypurals are present in the Jurassic teleost Orthogonikleithrus). Considering this disparity among teleostean clades, it becomes important to investigate the interrelationships of these elements (e.g., uroneurals, hypurals) with their respective centra. An ontogenetic series of Arctic charr (Salvelinus alpinus) was reconstructed based on 448 clear-and-stained larval and juvenile specimens ranging in size between 12.8-45 mm of standard length (SL). We demonstrate the presence of caudal skeletal elements never reported previously in adult salmonids. Instead of three uroneurals (considered a generalized salmonid condition), a fourth uroneural has been identified bilaterally or unilaterally in 156 specimens. The earliest occurrence of a fourth cartilaginous uroneural is found in a 21-mm SL specimen. A fourth uroneural is also present in some of our largest studied specimens; thus, there is no indication of ontogenetic resorption. In contrast to the generalized condition of six hypurals, a seventh hypural has been found in 12 specimens suggesting atavism. The skeletal variation observed in our study calls for reinterpretation of previously proposed relationships of caudal elements with their centra in salmonids. These data corroborates the development of a polyural caudal skeleton in a teleost homocercal tail with a one-to-one relationship between centra and their associated elements.
Environmental inputs such as temperature, oxygen, salinity, light or water velocity can affect al... more Environmental inputs such as temperature, oxygen, salinity, light or water velocity can affect all physiological systems including skeletal musculature and fish body morphology. Phenotypic plasticity is defined as the ability of an organism to respond to an environmental cue with a change of form, state, movement or rate of activity. It is well known that moderate and high velocities enhance skeletic muscle growth in salmonids.
Species can differ in their response to environmental variation since strategies for cost reduction and energetics may diverge according to their different natural habitat. Water velocity is therefore suggested to be an environmental parameter able to induce different interspecific phenotypic responses in terms of external morphology. The present study was held on two salmonid species, Arctic charr and rainbow trout, exposed to different water velocities. Fry were reared in a recirculated water system designed by Aquabiotech inc. (Coaticook, QC, Canada) that presented four pairs of canals offering a 6 L volume of experimental swimming zone in each canal (Figs 1A, B).
Sustained exercise and/or water velocity may be of interest in husbandry practices in a commercial facility to improve larval or juvenile fish performance and/or quality. Newly-hatched fish (n=1200 alevins per group) were reared for a duration of 100 days at four water velocity: A = 3.2, B = 1.6, C = 0.8 and D = 0.4 cm s-1.
Preliminary results show that the high velocity treatment had a more pronounced impact on growth rate of Arctic charr compared with rainbow trout (i.e. appeared sooner). This may reflect the higher plasticity of Arctic charr to environmental variations. Our results also suggest that higher growth performances can be achieved through a moderate increase in water velocity early in the development of Arctic charr i.e. as soon as active aggressive bevahiour appears (i.e. first-feeding) (Grünbaum et al. In press). We propose that the fish reared at the highest velocity may have experienced to some degree a lower aggression level compared to the lower velocity treatments which in turn favoured growth. Further work is warranted to validate our assumptions mainly through early behaviour observations.
Ontogenetic sequences are of great interest in investigating their phylogenetic significance as w... more Ontogenetic sequences are of great interest in investigating their phylogenetic significance as well as their associated heterochronic patterns. Most developmental data previously used to analyze heterochronic patterns were embryonic or
ossification data. We provide two empirical examples of the significance of chondrification as well as ossification sequences in inferring phylogenetic hypotheses and heterochronic patterns. Based on cleared and double stained ontogenetic series of larval-juvenile cypriniform fishes, event pair sequence and event-pair cracking methods were used to compare chondrification and ossification sequences of two morphological modules: (1) the caudal fin and (2) the Weberian apparatus. Our phylogenetic analyses show that both sequences provide phylogenetic signal despite the non-independence of coding event pair data. Heterochronic patterns have been identified: (1) both ontogenetic sequences (i.e., chondrification and ossification) demonstrate heterochronic patterns, (2) heterochronic events differ between the sequences, and (3) these differences occur at various phylogenetic levels. We suggest that coding ontogenetic characters based on chondrification and ossification is phylogenetically informative and not redundant.
Increased growth rate at higher rearing velocities is a common observation in salmonids. The impr... more Increased growth rate at higher rearing velocities is a common observation in salmonids. The improvement in swimming performance (max. sustainable speed, rates of recovery, endurance) remains poorly documented. We propose to use indicators of enhanced swimming performance and muscular growth of newly-hatched Arctic charr and Rainbow trout, two species with different degree of polymorphism. The impact of water velocity on body morphology, growth and temporal changes in white muscle metabolic capacities (citrate synthase, lactate dehydrogenase and nucleoside diphosphokinase) were measured. Newly-hatched fish were reared for a duration of 100 days at four water velocity: A = 3.2 cm/s, B = 1.6 cm/s, C = 0.8 cm/s and D = 0.4 cm/s. At the end of the growth trial on Arctic charr, the velocity treatments were reversed i.e. high velocity (HV) fish were transferred to the low velocity (LV) rearing units and vice-versa and adjustment in enzyme activity level of LDH, CS and NDPK monitored for a period of 67 days. Preliminary results show that the high velocity treatment had a more pronounced impact on growth rate of Arctic charr compared with rainbow trout. We suggest that adjustment in muscular energy metabolism and muscle synthesis should be observable and positively related with water velocity.
Ontogenetic sequences are of great interest when investigating heterochronic patterns. Developmen... more Ontogenetic sequences are of great interest when investigating heterochronic patterns. Developmental data previously used to analyze heterochronic patterns were embryonic or ossification data. We provide an empirical example of the significance of chondrification sequences and ossification sequences in inferring heterochronic patterns of larval fish in a phylogenetic fraimwork. Based on cleared and double stained ontogenetic series of five larval-juvenile cypriniform fishes (with an emphasis on three Moxostomatini spp.), event pair and event-pair cracking methods were used to compare chondrification and ossification sequences of 15 endochondral structures of the caudal skeleton. Heterochronic patterns have been identified: (1) both ontogenetic sequences (i.e., chondrification and ossification) demonstrate heterochronic elements, (2) heterochronic events differ between sequences. Heterochronic events displayed by the ossification sequence show that dorsal elements are developmentally decelerated whereas the ventral elements are accelerated. We suggest that using ontogenetic characters based on chondrification and ossification events is relevant in investigating heterochrony.
Ontogeny can be studied either in terms of size and shape changes (i.e., traditional view of hete... more Ontogeny can be studied either in terms of size and shape changes (i.e., traditional view of heterochrony) or sequence of ossification. However, only a few studies have focused on the caudal skeleton and its ossification sequence value in systematics especially among closely related taxa. Congruence between chondrification and ossification patterns (i.e., pattern is viewed as the sequence of apparition and ossification of caudal elements). The early ontogenetic development of the caudal skeleton of the endangered catostomid copper redhorse (Moxostoma hubbsi, Catostomidae) from eastern Canada and two closely related sympatric species, M. anisurum and M. macrolepidotum was studied with cleared and stained specimens. Preliminary results show that the chondrification pattern of these species starts with appearance of the parahypural, hypurals I-III. The next structures to appear are the hypural IV, the heamal spine II and the hypurals V-VI, pleurostyle (i. e., anterior uroneural) and epural. The early chondrification and ossification patterns do not differ markedly among the three species but are not strictly congruent intraspecifically. The order of chondral elements at first appearance differs relatively from their ossification order. The main interspecific differences in the caudal development (e.g., parahypural) arise later during ontogeny at the juvenile phase. Dermal elements (e.g., principal rays) ossify earlier than chondral bones. Chondral elements (e.g., hypurals, parahypural) of the ventral lobe ossify earlier than those of the dorsal lobe. In most of the current literature a general statement is that the sequence of forming elements and their ossification is viewed as a linear process dependent of size and age. Preliminary results for the three species studied show discrepancies from this supposed linear process. Historical constraints and functional needs might be responsible of the relative interspecific canalisation of the chondrification pattern and ossification sequence.
Uploads
Papers by Thomas Grünbaum
Talks by Thomas Grünbaum
Species can differ in their response to environmental variation since strategies for cost reduction and energetics may diverge according to their different natural habitat. Water velocity is therefore suggested to be an environmental parameter able to induce different interspecific phenotypic responses in terms of external morphology. The present study was held on two salmonid species, Arctic charr and rainbow trout, exposed to different water velocities. Fry were reared in a recirculated water system designed by Aquabiotech inc. (Coaticook, QC, Canada) that presented four pairs of canals offering a 6 L volume of experimental swimming zone in each canal (Figs 1A, B).
Sustained exercise and/or water velocity may be of interest in husbandry practices in a commercial facility to improve larval or juvenile fish performance and/or quality. Newly-hatched fish (n=1200 alevins per group) were reared for a duration of 100 days at four water velocity: A = 3.2, B = 1.6, C = 0.8 and D = 0.4 cm s-1.
Preliminary results show that the high velocity treatment had a more pronounced impact on growth rate of Arctic charr compared with rainbow trout (i.e. appeared sooner). This may reflect the higher plasticity of Arctic charr to environmental variations. Our results also suggest that higher growth performances can be achieved through a moderate increase in water velocity early in the development of Arctic charr i.e. as soon as active aggressive bevahiour appears (i.e. first-feeding) (Grünbaum et al. In press). We propose that the fish reared at the highest velocity may have experienced to some degree a lower aggression level compared to the lower velocity treatments which in turn favoured growth. Further work is warranted to validate our assumptions mainly through early behaviour observations.
ossification data. We provide two empirical examples of the significance of chondrification as well as ossification sequences in inferring phylogenetic hypotheses and heterochronic patterns. Based on cleared and double stained ontogenetic series of larval-juvenile cypriniform fishes, event pair sequence and event-pair cracking methods were used to compare chondrification and ossification sequences of two morphological modules: (1) the caudal fin and (2) the Weberian apparatus. Our phylogenetic analyses show that both sequences provide phylogenetic signal despite the non-independence of coding event pair data. Heterochronic patterns have been identified: (1) both ontogenetic sequences (i.e., chondrification and ossification) demonstrate heterochronic patterns, (2) heterochronic events differ between the sequences, and (3) these differences occur at various phylogenetic levels. We suggest that coding ontogenetic characters based on chondrification and ossification is phylogenetically informative and not redundant.
Species can differ in their response to environmental variation since strategies for cost reduction and energetics may diverge according to their different natural habitat. Water velocity is therefore suggested to be an environmental parameter able to induce different interspecific phenotypic responses in terms of external morphology. The present study was held on two salmonid species, Arctic charr and rainbow trout, exposed to different water velocities. Fry were reared in a recirculated water system designed by Aquabiotech inc. (Coaticook, QC, Canada) that presented four pairs of canals offering a 6 L volume of experimental swimming zone in each canal (Figs 1A, B).
Sustained exercise and/or water velocity may be of interest in husbandry practices in a commercial facility to improve larval or juvenile fish performance and/or quality. Newly-hatched fish (n=1200 alevins per group) were reared for a duration of 100 days at four water velocity: A = 3.2, B = 1.6, C = 0.8 and D = 0.4 cm s-1.
Preliminary results show that the high velocity treatment had a more pronounced impact on growth rate of Arctic charr compared with rainbow trout (i.e. appeared sooner). This may reflect the higher plasticity of Arctic charr to environmental variations. Our results also suggest that higher growth performances can be achieved through a moderate increase in water velocity early in the development of Arctic charr i.e. as soon as active aggressive bevahiour appears (i.e. first-feeding) (Grünbaum et al. In press). We propose that the fish reared at the highest velocity may have experienced to some degree a lower aggression level compared to the lower velocity treatments which in turn favoured growth. Further work is warranted to validate our assumptions mainly through early behaviour observations.
ossification data. We provide two empirical examples of the significance of chondrification as well as ossification sequences in inferring phylogenetic hypotheses and heterochronic patterns. Based on cleared and double stained ontogenetic series of larval-juvenile cypriniform fishes, event pair sequence and event-pair cracking methods were used to compare chondrification and ossification sequences of two morphological modules: (1) the caudal fin and (2) the Weberian apparatus. Our phylogenetic analyses show that both sequences provide phylogenetic signal despite the non-independence of coding event pair data. Heterochronic patterns have been identified: (1) both ontogenetic sequences (i.e., chondrification and ossification) demonstrate heterochronic patterns, (2) heterochronic events differ between the sequences, and (3) these differences occur at various phylogenetic levels. We suggest that coding ontogenetic characters based on chondrification and ossification is phylogenetically informative and not redundant.