Carlos Rosas | Universidad Nacional Autónoma de México (original) (raw)
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Articles by Carlos Rosas
Temperature is a key factor that modulates Octopus maya reproduction. Evidence shows that wild fe... more Temperature is a key factor that modulates Octopus maya reproduction. Evidence shows that wild females spawn when ambient natural temperatures are lower than 26°C, caused by either the winter sea temperatures or the upwelling events. The upwelling determines the availability of cold and nutrient rich water during spring and summer in the northern side of the Yucatán Peninsula (YP). We determined the effects of ambient temperature on the reproductive performance of female O. maya maintained in thermal regimes that simulate (a) high summer temperature at the eastern side of the YP (31°C), (b) winter temperature in all the YP (24°C), and (c) a temperature decrease (TD) at a rate of 1°C/5d from 31 to 24°C. The number of spawns, eggs spawned by female, fertilization percentage, embryos development, and hatchlings survival after starvation were evaluated for each thermal regime. At 31°C spawning of O. maya females is inhibited; only 13% spawned. The few fertilized eggs spawned died after two 2 weeks, indicating that high temperatures are deleterious to embryos. Females exposed to temperature changes of 1°C/5 d spawned only after temperature reached below 27°C, 87% of the females spawned. At the end TD treatment a mean value of 530 eggs per spawn was observed. Fertilization of spawns was around 50%. All the females maintained at 24°C spawned a mean of 1208 eggs/spawn with a 70.5% fertilization rate. Embryonic development was interrupted early in TD treatments causing premature hatchlings by day 31. These premature juveniles showed smaller sizes and low survival (48%) after a 10-day fast. In contrast, embryos spawned at 24°C exhibited larger development (45d), and hatchlings survival after a 10-day fast was 100%. Our results explain why O. maya spawns are limited to winter in the western side of the YP, when temperatures drop due to polar winds. Results also highlight the importance of the Yucatan upwelling for maintaining suitable conditions for spawning, embryo development, and hatchling survival along the year at Eastern border of the YP. We consider that this species could be negatively affected if climate change leads to an ocean warming scenario.
The thermoregulatory behavior of the giant keyhole limpet Megathura crenulata was determined in a... more The thermoregulatory behavior of the giant keyhole limpet Megathura crenulata was determined in a horizontal thermal gradient during the day at 18.9 1C and 18.3 1C for the night. The final preferendum determined for giant keyhole limpets was of 18.6 7 1.2 1C.
One of the major problems involved in the controlled cultivation of Patagonian red octopus (Enter... more One of the major problems involved in the controlled cultivation of Patagonian red octopus (Enteroctopus megalocyathus) is its long embryonic period ranging between 150-176 days, after which the hatching of planktonic paralarvae is achieved. The effect of temperature on the incubation of E. megalocyathus eggs was studied with the aim of establishing if a temperature higher than 12°C is effective to accelerate the embryonic development without altering their morphological and physiological conditions. Fertilized eggs obtained under controlled conditions at 11°C AE 0.1 were randomly distributed in 12 water baths of 30 L at 4 temperatures: 12, 14, 15 and 16°C AE 0.1°C. The experiment lasted until egg hatching occurred.The embryo growth rate was accelerated at 15-16°C, so the time spent in embryonic development can be reduced in 15% when compared with embryo development obtained from eggs incubated at 12°C. The embryos showed no significant differences in the final survival and were morphometrically similar in all stages of development at all temperatures. The increase in temperature from 12 to 16°C, even if it allowed a better growth, had high metabolic costs for embryos of E. megalocyathus. The activities of lipases and proteases were affected by interaction between temperature and the embryo stage, with high lipase activity observed in embryos of stage XV incubated at high temperatures and the highest levels of trypsin and chymotrypsin in stage XX at 14°C. The results suggest that 15°C could be the limit temperature to increase growth.
Octopus maya supports an important fishery in Yucatan Peninsula (YP) where this species is highly... more Octopus maya supports an important fishery in Yucatan Peninsula (YP) where this species is highly abundant. Considering that temperatures in the tropics are increasing (IPCC, 2013), there are several scenarios that can modify the dynamic of the O. maya population in YP: i) prolonged summer and short winter seasons, and/or ii) fast temperature increases and high temperatures after a winter season, both affecting the survival of hatchlings and the performance of juveniles. The present study was designed to evaluate the effect of maternal temperature stress over hatchling and juvenile performance in terms of their energetic plasticity and thermoregulatory behaviour, when they were exposed to a gradual temperature increase (TI) from 24 to 30°C and compared with hatchlings maintained at preferred and constant temperature (24°C). Hatchlings from stressed females were smaller, and had a lower growth rate compared to those from unstressed females providing evidence that temperature stress experienced by females has consequences on the performance of hatchlings, with effects on the biomass production and survival. Results also demonstrated that hatchlings exposed to TI (24-30°C) had a growth rate and oxygen consumption similar to those maintained at preferred temperature (24°C), in both female groups indicating that a gradual temperature increase of 1°C every 5 days is probably enough to allow the organisms to make physiological adjustments without an excessive energetic cost.
Octopus maya is one of the most promising candidates for octopus aquaculture due to its holobenth... more Octopus maya is one of the most promising candidates for octopus aquaculture due to its holobenthic development. The objectives of this study were to investigate: i) whether the time required for embryonic development of this species can be reduced; ii) whether high or low temperatures affect the size and physiological characteristics of embryos; iii) whether temperature affects the time taken to reach stage XX, using thermal time; and iv) the effects of incubation temperature on hatchling performance, measured as survival after 10 d fasting. Eggs were acclimated at 18, 22, 26 and 30°C. Embryos incubated at 30°C reached stage XX 50 d before embryos incubated at 18°C. A mean value of 596 degrees day −1 was obtained for embryos incubated at 22 and 26°C where embryo development was optimum. Principal component analysis showed that arm length was the morphological characteristic that separated embryos incubated at 22°C from the rest of the treatments. Embryos in stage XIX and incubated at 26°C had a higher metabolic rate than embryos maintained at other experimental temperatures. The best hatchling performance was obtained with embryos incubated at 22°C. Results indicated that the optimal temperature for O. maya incubation is in the range of 22-26°C. Statement of relevance: Octopus maya is one of the most promising species for octopus aquaculture due its holobenthic development. This study will be useful when design production facilities because it gives key information to obtain the hatchlings with the best performance.
On the Yucatan Peninsula there is an upwelling which allows access to a body of cold water that c... more On the Yucatan Peninsula there is an upwelling which allows access to a body of cold water that controls temperature in this area. This modulates the ecology and distribution of organisms that inhabit the continental shelf. The objective of this study was to determine the effect of different acclimation temperatures on the thermal biology of prey as mollusc, crustacean (Melongena corona bispinosa, Strombus pugilis, Callinectes similis, Libinia dubia) and predators as fish (Ocyurus chrysurus, Centropomus undecimalis) of Octopus maya. Octopus prey preferred temperatures between 23.5°C and 26.0°C, while predators preferred temperatures 26.4-28.5°C. The species with largest thermal windows were M. corona bispinosa (328.8°C 2 ), C. similis (322.8°C 2 ), L. dubia (319.2°C 2 ), C. undecimalis (288.6°C 2 ), O. chrysurus (237.5°C 2 ), while the smallest thermal window was for S. pugilis (202.0°C 2 ). The acclimation response ratios (ARR) estimated for prey ranged from 0.24-0.55 in animals exposed to CTMax and 0.21-0.65 in those exposed to CTMin. Amongst predators, ARR ranged from 0.30 to 0.60 and 0.41 to 0.53 for animals exposed to CTMax and CTMin, respectively. Correlating the optimal temperature limits of prey and predators with surface temperatures on the continental shelf and those 4 m deep showed that the main prey, Callinectes similis and L. dubia, shared a thermal niche and that an increase in temperature could force these species to migrate to other sites to find optimal temperatures for their physiological functions. As a consequence the continental shelf community would undergo a structural change. Predators were found to be near their optimal temperatures in surface temperatures on the continental shelf. We conclude that they would remain in the area in a warming scenario.
Aquatic Biology, 2011
The cephalopod digestive gland (DG) is responsible for enzyme production as well as nutrient and ... more The cephalopod digestive gland (DG) is responsible for enzyme production as well as nutrient and lipid storage. Octopus maya (Mollusca: Cephalopoda) is a holobenthic octopus species with aquaculture potential. To develop a balanced food for the rearing of this octopus, it is necessary to understand its digestive physiology. We performed histological studies on the structural change of the DG (cytological ontogeny) associated with age (from 0 to 30 d posthatching, DPH) and food (postprandial change in 120 DPH juveniles). Early ontogeny of DG was defined in 3 stages: (1) yolk platelets stage (0 to 5 DPH), (2) transition stage (6 to 10 DPH) and (3) heterolysosomes (food reserves) stage (>12 DPH). In Stage 1, the DG had anatomically undifferentiated tubules, but was filled with yolk platelets. The tubular structures developed lumen by 5 DPH. Stage 2 (starting at 6 DPH) corresponds to mixed exogenous and endogenous feeding. At that time, the yolk platelets were gradually consumed until completely exhausted at 9 DPH. At the onset of Stage 3, the DG structure was completely tubular, exhibiting digestive cell microvilli and other cellular features typical to octupus DGs. During exogenous feeding (12 DPH and onward), acidophilic secretory lysosomes, heterolysosomes and some heterophagosomes appeared on DG cells. O. maya has long digestive cycles in which the extracellular and intracellular digestion can take up to 8 h. Although the ecological implications of this information for aquaculture will still have to be proven, results demonstrated that O. maya is an energetically efficient species and thus suitable for rearing in captivity.
In the present study, digestive dynamics, measured through the changes in the in situ pHalong the... more In the present study, digestive dynamics, measured
through the changes in the in situ pHalong the digestive
tract, was evaluated along with the glycogen
concentration in the digestive gland (DG) and the
proteolytic enzyme activity of the gastric juice (GJ)
(both acid and alkaline proteases) to obtain useful information
that will allow for the understanding of
the DG’s function and the role that it plays as an extracellular
digestive enzyme source and for energy
storage, providing new information on the digestive
physiology of Octopus maya. The results showed that
pH along the digestive tract changed according to the
postprandial time following the food transit. At the beginning,
the pHoncrop (St)was 5, changing to 6when
the food arrived. Similar changeswere observed onthe
caecum (Ce) and DG. Glycogen from DG is used as a
source of energy during digestion and recovered 8 h
after feeding. Maximum activities of digestive gland
GJ enzymeswere observed 6 h after feeding, indicating
that chyme enzymes are still activewhen theyarrive at
the DG’s lumen. The presence of food in the digestive
tract modi¢es the pH, which, in combination with GJ,
favours the activity of the released enzymes of O. maya.
Proteinases from hepatopancreas (HP) and gastric juice (GJ) from wild and cultured red octopus (O... more Proteinases from hepatopancreas (HP) and gastric juice (GJ) from wild and
cultured red octopus (Octopus maya) were characterized. Hepatopancreas assays revealed
optimal activity at pH 4, 9–10 and 10 for wild and pH 3, 8, and 9, for cultured octopuses,
for total proteinases, trypsin and chymotrypsin, respectively. In the gastric juice, maximum
activity was recorded at pH 6, 8, and 7 for total proteinases, trypsin, and chymotrypsin,
respectively for both wild and cultured octopus. A reduction on enzyme activity of 70 and
20% was observed in HP and GJ extracts, respectively when protease inhibitor Pepstatin A
was used. That result suggests that the main proteases in the HP were aspartic acid
proteinases type (possibly Cathepsin D) and some of them were present in the GJ. Dissociating
discontinuous polyacrylamide gel electrophoresis showed activity bands between
20 and 28, 30 and 34, 35 and 45, 60 and 70 kDa, and a last one between 75 and 100 kDa.
We concluded that extracellular digestion of O. maya takes place in an acid environment,
around pH 6. In contrast, intracellular digestion in the HP is developed at pHs between 3
and 4, where cathepsin D could be the most important enzyme for O. maya.
Malacologia, Dec 2013
Commercially available radioimmunoassays (RIA) with 125 I-labeled hormones were adapted, develope... more Commercially available radioimmunoassays (RIA) with 125 I-labeled hormones were adapted, developed and validated to quantify progesterone and testosterone in gonad extracts of Octopus maya, considered an easily domesticated species with potential in aquaculture. Development of the RIAs was divided into four phases: (1) extraction of progesterone and testosterone from gonads, (2) preparation of gonad extracts for RIA, (3) standards preparation, and (4) RIA procedure. Hormones were extracted twice with 15 mL of diethyl-ether each time. The recovered hormone and the solvent effect on extraction were evaluated. RIAs were vali--1 , and did not change by more than 20% during the 125 I half-life. Accuracy was 102.25 ± 11.22% for progesterone and 81.62 ± 6.24% for testosterone. For both hormones, precision was close to 13% and reproducibility 17%. The precision/reproducibility ratio indicated a system with good stability. The amounts of the hormones recovered increased when the number of extractions was increased. Hormone concentrations also increased when the volume of diethyl-ether used per extraction study is in agreement with the range found in other octopuses. Finally, the developed and Octopus gonad extracts and show that it is possible to use 125 I-labeled hormone as well as the plastic coated-tubes from commercial RIA kits to analyse variations in hormone levels associated with gonad developmental stages and the reproductive cycle of octopuses, allowing exploration of their possible functions.
Biological Bulletin, Jan 1, 2009
Gonad development during the early life of Octopus maya is described in terms of histological, mo... more Gonad development during the early life of Octopus maya is described in terms of histological, morphometric, oocytes growth, and somatic-oocyte relationship data obtained from octopus cultured at the UMDI-UNAM, in Sisal, Yucatan, Mexico. This study is the first publication on gonad development during the early life of Octopus maya. A total of 83 O. maya specimens were used; their sizes ranged from 6.5 to 76 mm of total length (TL), 4 to 28 mm of dorsal mantle length (DML), 2.5 to 20 mm of ventral mantle length (VML), and 0.0180 to 7.2940 g of fixed body weight (fBW). Animals were weighed and measured only after preservation. A loss of 10% of living weight was estimated for juvenile octopuses after formalin preservation. The relation of length to weight (VML, DML, TL/fBW) pooled for both sexes had a strong positive correlation (r), as shown by a potential power function that was quite close to 1. Compound images were produced from numerous microscopic fields. The histological examination revealed that, 4 months after hatching, male octopus (24.5 mm DML and 7.2940 g fBW) were in gonad stages 2 (maturing) to 3 (mature), with spermatogonia and spermatocytes in the tubule wall and abundant spermatids and spermatozoa in the central lumen of the seminiferous tubules, suggesting the occurrence of different phases of gonad development at different maturity stages. In contrast, females (22.5 mm DML and 4.8210 g fBW) at the same time since hatching were immature (stage 1), with many oogonia, few oocytes, and germinal epithelium. This suggests that males reach maturity earlier than females, indicating a probable onset of maturity for males at around 4 months of culture or 8 g of wet body weight. Our results indicate the possibility that the size-at-weight can be recognized early with a degree of certainty that allows the sexes to be separated for culture purposes; but more detailed studies on reproduction in relation to endocrinology and nutrition are needed.
Papers by Carlos Rosas
Ecological Indicators, 2020
Temperature is recongnised as the main factor controlling the species fitness and performance. Na... more Temperature is recongnised as the main factor controlling the species fitness and performance. Naturally, the thermal preferences (TP) of aquatic organisms obtained in controlled conditions have been used to relate physiological performance with field data since they are a good proxy to the fundamental niche. Literature suggests that dispersal capabilities, biological interactions, acclimatisation, adaptation, among others might play a role in species distribution; thus, in reality, species are usually occupying a realized thermal niche (RTN). Therefore, this study was designed to inquire into the following questions: Are the TP of tropical aquatic ectotherms found in laboratory conditions similar to their RTN? Can TP be validated with occurrences in the wild? To answer these questions, this study compared the TP obtained from previously published works with the RTN of the crabs Callinectes similis and C. sapidus, the fishes Centropomus undecimalis and Ocyurus chrysurus, the lobster Panulirus argus, and the octopus Octopus maya obtained from occurrences from 1693documents. When RTN values were tested against the TPs obtained in laboratory, no significant differences were found for fish species (P > 0.05); in contrast, differences for the benthic invertebrates were reported (P < 0.05). At least two factors could have been affecting these results: differences in the average tolerances between geographically distinct populations (local adaptation) and the dispersal capabilities that might have been forcing a differentiation between populations If, as proposed, fishes can actively follow thermal optimum, their response to warming scenarios could be faster than benthic organisms. If our hypothesis is true, the uncertainty of climate change could be reduced when the local adaptation is taking into consideration. movement, and reproduction are dependent on temperature, which provokes effects at organismal, population, community, and ecosystem levels (Angilletta, 2009) and make temperature an influencing factor through the rate at which an organism can perform an ecologically relevant activity (
Journal of Experimental Marine Biology and Ecology, 2016
Abstract The seahorse Hippocampus erectus inhabits estuaries and coastal areas from southern Cana... more Abstract The seahorse Hippocampus erectus inhabits estuaries and coastal areas from southern Canada to northern Brazil, including the Yucatan Peninsula (YP), Mexico. Fish species living in thermally heterogeneous environments have developed physiological and behavioural adjustments that provide individuals with the phenotypic plasticity to respond to environmental changes within certain limits. When thermal changes exceed the ability of fish to adjust, energy supply is predominantly directed to fuel essential maintenance costs at the expense of growth and reproduction. In such circumstances, not only temperature, but also time of exposure, are elements that determine the adaptive value of phenotypic plasticity. The present study was designed to examine the consequences of acclimation of juvenile H. erectus to 18 and 30 °C on the phenotypic plasticity associated with exposure to acute thermal events (measured through the thermal limits) and chronic exposure during longer periods (measured through growth). Similar survival and growth was found in all seahorses that experienced acute exposure (~ 1 min) to temperatures ranging from 7 to 33 °C and 12 to 36 °C in both acclimation treatments, respectively. Chronic exposure to 30 °C compared to 18 °C, however, significantly reduced seahorse growth. A thermal tolerance polygon calculated as 302 °C 2 suggests that H. erectus has a wide tolerance to the extreme conditions commonly present in estuarine environments. Given that the amplitude in the thermal tolerance polygon was mainly due to an increase in the lower limits of the interval and that no minimum temperature threshold could be determined, thus suggesting that the populations from YP are near their upper thermal limit.
Ecological Indicators, 2019
H., Olivares, A., Diaz, F. and Rosas, C. (2017). Temperature modulates spatio-temporal variabilit... more H., Olivares, A., Diaz, F. and Rosas, C. (2017). Temperature modulates spatio-temporal variability of the functional reproductive maturation of Octopus maya (Cephalopoda) on the shelf of the Yucatan Peninsula, Mexico. J.
Ecological Indicators, 2017
Tropical populations of marine species are predicted to be the most impacted by global warming be... more Tropical populations of marine species are predicted to be the most impacted by global warming because they are likely adapted to a narrow range of temperatures in their local environment. In the present study, we investigated the thermal range at which activity metabolic rate (AMR) is maximal, pejus, and critical in the spiny lobster Panulirus argus using different ecophysiological biomarkers. Lobsters were acclimated at constant temperatures (18, 22, 26 and 30 • C; N = 150) at laboratory conditions for 35 days; after that time thermal biology was evaluated. Results obtained demonstrated that, in P. argus the temperature where AMR was maximal does not coincide with temperature that promotes the maximum growth rate (26 • C). In fact, the preferred temperature, determined in a horizontal gradient was around the mean value of 27.5 • C, 5.5 • C above the temperature where animals showed their maximum metabolic scope, growth and thermal preference. Lactate and redox imbalance showed its maximum values in animals acclimated at 30 • C indicating that lobsters where in pejus thermal ranges. Although lobsters are adapted to tolerate temperatures beyond 28 • C, results indicated that temperature and exposure time play important roles in the way organisms respond to thermal challenges. It is likely that the difference in the responses of different ectothermic organisms and the thermal response is linked to the way these effects are measured. These results can help generate predictive models to anticipate changes in the P. argus fishery derived from likely changes in distribution and abundance of this species under warming scenarios of tropical oceans.
Biology open, Jan 15, 2016
Optimum temperatures can be measured through aerobic scope, preferred temperatures or growth. A c... more Optimum temperatures can be measured through aerobic scope, preferred temperatures or growth. A complete thermal window, including optimum, transition (Pejus) and critical temperatures (CT), can be described if preferred temperatures and CT are defined. The crustacean Hemigrapsus crenulatus was used as a model species to evaluate the effect of acclimation temperature on: (i) thermal preference and width of thermal window, (ii) respiratory metabolism, and (iii) haemolymph proteins. Dependant on acclimation temperature, preferred temperature was between 11.8°C and 25.2°C while CT was found between a minimum of 2.7°C (CTmin) and a maximum of 35.9°C (CTmax). These data and data from tropical and temperate crustaceans were compared to examine the association between environmental temperature and thermal tolerance. Temperate species have a CTmax limit around 35°C that corresponded with the low CTmax limit of tropical species (34-36°C). Tropical species showed a CTmin limit around 9°C simi...
Ciencias Marinas, 2012
The phylogenic relationships among the Octopus species have not been fully established. We compar... more The phylogenic relationships among the Octopus species have not been fully established. We compared sequences for three mitochondrial genes (16S ribosomal RNA, cytochrome oxydase I, and cytochrome oxydase III) from Octopus maya, an endemic taxon of the Yucatan Peninsula, with homologous sequences from other taxa within the Octopus genus, with the aim of elucidating the phylogenetic relationships of this species. Maximum likelihood trees grouped O. maya with octopuses that inhabit the East Pacific. Considering that the distribution of O. maya is limited to the Yucatan peninsula in the West Atlantic and that the sequences analyzed show equal evolutionary rates across taxa, we propose that the divergence of O. maya possibly started during the formation of the Panama Isthmus, when the Pacific and Atlantic basins were split. The genetic distances that O. maya sequences show within the trees obtained are in the range of congeneric distances of other taxa in this genus so that these sequen...
Temperature is a key factor that modulates Octopus maya reproduction. Evidence shows that wild fe... more Temperature is a key factor that modulates Octopus maya reproduction. Evidence shows that wild females spawn when ambient natural temperatures are lower than 26°C, caused by either the winter sea temperatures or the upwelling events. The upwelling determines the availability of cold and nutrient rich water during spring and summer in the northern side of the Yucatán Peninsula (YP). We determined the effects of ambient temperature on the reproductive performance of female O. maya maintained in thermal regimes that simulate (a) high summer temperature at the eastern side of the YP (31°C), (b) winter temperature in all the YP (24°C), and (c) a temperature decrease (TD) at a rate of 1°C/5d from 31 to 24°C. The number of spawns, eggs spawned by female, fertilization percentage, embryos development, and hatchlings survival after starvation were evaluated for each thermal regime. At 31°C spawning of O. maya females is inhibited; only 13% spawned. The few fertilized eggs spawned died after two 2 weeks, indicating that high temperatures are deleterious to embryos. Females exposed to temperature changes of 1°C/5 d spawned only after temperature reached below 27°C, 87% of the females spawned. At the end TD treatment a mean value of 530 eggs per spawn was observed. Fertilization of spawns was around 50%. All the females maintained at 24°C spawned a mean of 1208 eggs/spawn with a 70.5% fertilization rate. Embryonic development was interrupted early in TD treatments causing premature hatchlings by day 31. These premature juveniles showed smaller sizes and low survival (48%) after a 10-day fast. In contrast, embryos spawned at 24°C exhibited larger development (45d), and hatchlings survival after a 10-day fast was 100%. Our results explain why O. maya spawns are limited to winter in the western side of the YP, when temperatures drop due to polar winds. Results also highlight the importance of the Yucatan upwelling for maintaining suitable conditions for spawning, embryo development, and hatchling survival along the year at Eastern border of the YP. We consider that this species could be negatively affected if climate change leads to an ocean warming scenario.
The thermoregulatory behavior of the giant keyhole limpet Megathura crenulata was determined in a... more The thermoregulatory behavior of the giant keyhole limpet Megathura crenulata was determined in a horizontal thermal gradient during the day at 18.9 1C and 18.3 1C for the night. The final preferendum determined for giant keyhole limpets was of 18.6 7 1.2 1C.
One of the major problems involved in the controlled cultivation of Patagonian red octopus (Enter... more One of the major problems involved in the controlled cultivation of Patagonian red octopus (Enteroctopus megalocyathus) is its long embryonic period ranging between 150-176 days, after which the hatching of planktonic paralarvae is achieved. The effect of temperature on the incubation of E. megalocyathus eggs was studied with the aim of establishing if a temperature higher than 12°C is effective to accelerate the embryonic development without altering their morphological and physiological conditions. Fertilized eggs obtained under controlled conditions at 11°C AE 0.1 were randomly distributed in 12 water baths of 30 L at 4 temperatures: 12, 14, 15 and 16°C AE 0.1°C. The experiment lasted until egg hatching occurred.The embryo growth rate was accelerated at 15-16°C, so the time spent in embryonic development can be reduced in 15% when compared with embryo development obtained from eggs incubated at 12°C. The embryos showed no significant differences in the final survival and were morphometrically similar in all stages of development at all temperatures. The increase in temperature from 12 to 16°C, even if it allowed a better growth, had high metabolic costs for embryos of E. megalocyathus. The activities of lipases and proteases were affected by interaction between temperature and the embryo stage, with high lipase activity observed in embryos of stage XV incubated at high temperatures and the highest levels of trypsin and chymotrypsin in stage XX at 14°C. The results suggest that 15°C could be the limit temperature to increase growth.
Octopus maya supports an important fishery in Yucatan Peninsula (YP) where this species is highly... more Octopus maya supports an important fishery in Yucatan Peninsula (YP) where this species is highly abundant. Considering that temperatures in the tropics are increasing (IPCC, 2013), there are several scenarios that can modify the dynamic of the O. maya population in YP: i) prolonged summer and short winter seasons, and/or ii) fast temperature increases and high temperatures after a winter season, both affecting the survival of hatchlings and the performance of juveniles. The present study was designed to evaluate the effect of maternal temperature stress over hatchling and juvenile performance in terms of their energetic plasticity and thermoregulatory behaviour, when they were exposed to a gradual temperature increase (TI) from 24 to 30°C and compared with hatchlings maintained at preferred and constant temperature (24°C). Hatchlings from stressed females were smaller, and had a lower growth rate compared to those from unstressed females providing evidence that temperature stress experienced by females has consequences on the performance of hatchlings, with effects on the biomass production and survival. Results also demonstrated that hatchlings exposed to TI (24-30°C) had a growth rate and oxygen consumption similar to those maintained at preferred temperature (24°C), in both female groups indicating that a gradual temperature increase of 1°C every 5 days is probably enough to allow the organisms to make physiological adjustments without an excessive energetic cost.
Octopus maya is one of the most promising candidates for octopus aquaculture due to its holobenth... more Octopus maya is one of the most promising candidates for octopus aquaculture due to its holobenthic development. The objectives of this study were to investigate: i) whether the time required for embryonic development of this species can be reduced; ii) whether high or low temperatures affect the size and physiological characteristics of embryos; iii) whether temperature affects the time taken to reach stage XX, using thermal time; and iv) the effects of incubation temperature on hatchling performance, measured as survival after 10 d fasting. Eggs were acclimated at 18, 22, 26 and 30°C. Embryos incubated at 30°C reached stage XX 50 d before embryos incubated at 18°C. A mean value of 596 degrees day −1 was obtained for embryos incubated at 22 and 26°C where embryo development was optimum. Principal component analysis showed that arm length was the morphological characteristic that separated embryos incubated at 22°C from the rest of the treatments. Embryos in stage XIX and incubated at 26°C had a higher metabolic rate than embryos maintained at other experimental temperatures. The best hatchling performance was obtained with embryos incubated at 22°C. Results indicated that the optimal temperature for O. maya incubation is in the range of 22-26°C. Statement of relevance: Octopus maya is one of the most promising species for octopus aquaculture due its holobenthic development. This study will be useful when design production facilities because it gives key information to obtain the hatchlings with the best performance.
On the Yucatan Peninsula there is an upwelling which allows access to a body of cold water that c... more On the Yucatan Peninsula there is an upwelling which allows access to a body of cold water that controls temperature in this area. This modulates the ecology and distribution of organisms that inhabit the continental shelf. The objective of this study was to determine the effect of different acclimation temperatures on the thermal biology of prey as mollusc, crustacean (Melongena corona bispinosa, Strombus pugilis, Callinectes similis, Libinia dubia) and predators as fish (Ocyurus chrysurus, Centropomus undecimalis) of Octopus maya. Octopus prey preferred temperatures between 23.5°C and 26.0°C, while predators preferred temperatures 26.4-28.5°C. The species with largest thermal windows were M. corona bispinosa (328.8°C 2 ), C. similis (322.8°C 2 ), L. dubia (319.2°C 2 ), C. undecimalis (288.6°C 2 ), O. chrysurus (237.5°C 2 ), while the smallest thermal window was for S. pugilis (202.0°C 2 ). The acclimation response ratios (ARR) estimated for prey ranged from 0.24-0.55 in animals exposed to CTMax and 0.21-0.65 in those exposed to CTMin. Amongst predators, ARR ranged from 0.30 to 0.60 and 0.41 to 0.53 for animals exposed to CTMax and CTMin, respectively. Correlating the optimal temperature limits of prey and predators with surface temperatures on the continental shelf and those 4 m deep showed that the main prey, Callinectes similis and L. dubia, shared a thermal niche and that an increase in temperature could force these species to migrate to other sites to find optimal temperatures for their physiological functions. As a consequence the continental shelf community would undergo a structural change. Predators were found to be near their optimal temperatures in surface temperatures on the continental shelf. We conclude that they would remain in the area in a warming scenario.
Aquatic Biology, 2011
The cephalopod digestive gland (DG) is responsible for enzyme production as well as nutrient and ... more The cephalopod digestive gland (DG) is responsible for enzyme production as well as nutrient and lipid storage. Octopus maya (Mollusca: Cephalopoda) is a holobenthic octopus species with aquaculture potential. To develop a balanced food for the rearing of this octopus, it is necessary to understand its digestive physiology. We performed histological studies on the structural change of the DG (cytological ontogeny) associated with age (from 0 to 30 d posthatching, DPH) and food (postprandial change in 120 DPH juveniles). Early ontogeny of DG was defined in 3 stages: (1) yolk platelets stage (0 to 5 DPH), (2) transition stage (6 to 10 DPH) and (3) heterolysosomes (food reserves) stage (>12 DPH). In Stage 1, the DG had anatomically undifferentiated tubules, but was filled with yolk platelets. The tubular structures developed lumen by 5 DPH. Stage 2 (starting at 6 DPH) corresponds to mixed exogenous and endogenous feeding. At that time, the yolk platelets were gradually consumed until completely exhausted at 9 DPH. At the onset of Stage 3, the DG structure was completely tubular, exhibiting digestive cell microvilli and other cellular features typical to octupus DGs. During exogenous feeding (12 DPH and onward), acidophilic secretory lysosomes, heterolysosomes and some heterophagosomes appeared on DG cells. O. maya has long digestive cycles in which the extracellular and intracellular digestion can take up to 8 h. Although the ecological implications of this information for aquaculture will still have to be proven, results demonstrated that O. maya is an energetically efficient species and thus suitable for rearing in captivity.
In the present study, digestive dynamics, measured through the changes in the in situ pHalong the... more In the present study, digestive dynamics, measured
through the changes in the in situ pHalong the digestive
tract, was evaluated along with the glycogen
concentration in the digestive gland (DG) and the
proteolytic enzyme activity of the gastric juice (GJ)
(both acid and alkaline proteases) to obtain useful information
that will allow for the understanding of
the DG’s function and the role that it plays as an extracellular
digestive enzyme source and for energy
storage, providing new information on the digestive
physiology of Octopus maya. The results showed that
pH along the digestive tract changed according to the
postprandial time following the food transit. At the beginning,
the pHoncrop (St)was 5, changing to 6when
the food arrived. Similar changeswere observed onthe
caecum (Ce) and DG. Glycogen from DG is used as a
source of energy during digestion and recovered 8 h
after feeding. Maximum activities of digestive gland
GJ enzymeswere observed 6 h after feeding, indicating
that chyme enzymes are still activewhen theyarrive at
the DG’s lumen. The presence of food in the digestive
tract modi¢es the pH, which, in combination with GJ,
favours the activity of the released enzymes of O. maya.
Proteinases from hepatopancreas (HP) and gastric juice (GJ) from wild and cultured red octopus (O... more Proteinases from hepatopancreas (HP) and gastric juice (GJ) from wild and
cultured red octopus (Octopus maya) were characterized. Hepatopancreas assays revealed
optimal activity at pH 4, 9–10 and 10 for wild and pH 3, 8, and 9, for cultured octopuses,
for total proteinases, trypsin and chymotrypsin, respectively. In the gastric juice, maximum
activity was recorded at pH 6, 8, and 7 for total proteinases, trypsin, and chymotrypsin,
respectively for both wild and cultured octopus. A reduction on enzyme activity of 70 and
20% was observed in HP and GJ extracts, respectively when protease inhibitor Pepstatin A
was used. That result suggests that the main proteases in the HP were aspartic acid
proteinases type (possibly Cathepsin D) and some of them were present in the GJ. Dissociating
discontinuous polyacrylamide gel electrophoresis showed activity bands between
20 and 28, 30 and 34, 35 and 45, 60 and 70 kDa, and a last one between 75 and 100 kDa.
We concluded that extracellular digestion of O. maya takes place in an acid environment,
around pH 6. In contrast, intracellular digestion in the HP is developed at pHs between 3
and 4, where cathepsin D could be the most important enzyme for O. maya.
Malacologia, Dec 2013
Commercially available radioimmunoassays (RIA) with 125 I-labeled hormones were adapted, develope... more Commercially available radioimmunoassays (RIA) with 125 I-labeled hormones were adapted, developed and validated to quantify progesterone and testosterone in gonad extracts of Octopus maya, considered an easily domesticated species with potential in aquaculture. Development of the RIAs was divided into four phases: (1) extraction of progesterone and testosterone from gonads, (2) preparation of gonad extracts for RIA, (3) standards preparation, and (4) RIA procedure. Hormones were extracted twice with 15 mL of diethyl-ether each time. The recovered hormone and the solvent effect on extraction were evaluated. RIAs were vali--1 , and did not change by more than 20% during the 125 I half-life. Accuracy was 102.25 ± 11.22% for progesterone and 81.62 ± 6.24% for testosterone. For both hormones, precision was close to 13% and reproducibility 17%. The precision/reproducibility ratio indicated a system with good stability. The amounts of the hormones recovered increased when the number of extractions was increased. Hormone concentrations also increased when the volume of diethyl-ether used per extraction study is in agreement with the range found in other octopuses. Finally, the developed and Octopus gonad extracts and show that it is possible to use 125 I-labeled hormone as well as the plastic coated-tubes from commercial RIA kits to analyse variations in hormone levels associated with gonad developmental stages and the reproductive cycle of octopuses, allowing exploration of their possible functions.
Biological Bulletin, Jan 1, 2009
Gonad development during the early life of Octopus maya is described in terms of histological, mo... more Gonad development during the early life of Octopus maya is described in terms of histological, morphometric, oocytes growth, and somatic-oocyte relationship data obtained from octopus cultured at the UMDI-UNAM, in Sisal, Yucatan, Mexico. This study is the first publication on gonad development during the early life of Octopus maya. A total of 83 O. maya specimens were used; their sizes ranged from 6.5 to 76 mm of total length (TL), 4 to 28 mm of dorsal mantle length (DML), 2.5 to 20 mm of ventral mantle length (VML), and 0.0180 to 7.2940 g of fixed body weight (fBW). Animals were weighed and measured only after preservation. A loss of 10% of living weight was estimated for juvenile octopuses after formalin preservation. The relation of length to weight (VML, DML, TL/fBW) pooled for both sexes had a strong positive correlation (r), as shown by a potential power function that was quite close to 1. Compound images were produced from numerous microscopic fields. The histological examination revealed that, 4 months after hatching, male octopus (24.5 mm DML and 7.2940 g fBW) were in gonad stages 2 (maturing) to 3 (mature), with spermatogonia and spermatocytes in the tubule wall and abundant spermatids and spermatozoa in the central lumen of the seminiferous tubules, suggesting the occurrence of different phases of gonad development at different maturity stages. In contrast, females (22.5 mm DML and 4.8210 g fBW) at the same time since hatching were immature (stage 1), with many oogonia, few oocytes, and germinal epithelium. This suggests that males reach maturity earlier than females, indicating a probable onset of maturity for males at around 4 months of culture or 8 g of wet body weight. Our results indicate the possibility that the size-at-weight can be recognized early with a degree of certainty that allows the sexes to be separated for culture purposes; but more detailed studies on reproduction in relation to endocrinology and nutrition are needed.
Ecological Indicators, 2020
Temperature is recongnised as the main factor controlling the species fitness and performance. Na... more Temperature is recongnised as the main factor controlling the species fitness and performance. Naturally, the thermal preferences (TP) of aquatic organisms obtained in controlled conditions have been used to relate physiological performance with field data since they are a good proxy to the fundamental niche. Literature suggests that dispersal capabilities, biological interactions, acclimatisation, adaptation, among others might play a role in species distribution; thus, in reality, species are usually occupying a realized thermal niche (RTN). Therefore, this study was designed to inquire into the following questions: Are the TP of tropical aquatic ectotherms found in laboratory conditions similar to their RTN? Can TP be validated with occurrences in the wild? To answer these questions, this study compared the TP obtained from previously published works with the RTN of the crabs Callinectes similis and C. sapidus, the fishes Centropomus undecimalis and Ocyurus chrysurus, the lobster Panulirus argus, and the octopus Octopus maya obtained from occurrences from 1693documents. When RTN values were tested against the TPs obtained in laboratory, no significant differences were found for fish species (P > 0.05); in contrast, differences for the benthic invertebrates were reported (P < 0.05). At least two factors could have been affecting these results: differences in the average tolerances between geographically distinct populations (local adaptation) and the dispersal capabilities that might have been forcing a differentiation between populations If, as proposed, fishes can actively follow thermal optimum, their response to warming scenarios could be faster than benthic organisms. If our hypothesis is true, the uncertainty of climate change could be reduced when the local adaptation is taking into consideration. movement, and reproduction are dependent on temperature, which provokes effects at organismal, population, community, and ecosystem levels (Angilletta, 2009) and make temperature an influencing factor through the rate at which an organism can perform an ecologically relevant activity (
Journal of Experimental Marine Biology and Ecology, 2016
Abstract The seahorse Hippocampus erectus inhabits estuaries and coastal areas from southern Cana... more Abstract The seahorse Hippocampus erectus inhabits estuaries and coastal areas from southern Canada to northern Brazil, including the Yucatan Peninsula (YP), Mexico. Fish species living in thermally heterogeneous environments have developed physiological and behavioural adjustments that provide individuals with the phenotypic plasticity to respond to environmental changes within certain limits. When thermal changes exceed the ability of fish to adjust, energy supply is predominantly directed to fuel essential maintenance costs at the expense of growth and reproduction. In such circumstances, not only temperature, but also time of exposure, are elements that determine the adaptive value of phenotypic plasticity. The present study was designed to examine the consequences of acclimation of juvenile H. erectus to 18 and 30 °C on the phenotypic plasticity associated with exposure to acute thermal events (measured through the thermal limits) and chronic exposure during longer periods (measured through growth). Similar survival and growth was found in all seahorses that experienced acute exposure (~ 1 min) to temperatures ranging from 7 to 33 °C and 12 to 36 °C in both acclimation treatments, respectively. Chronic exposure to 30 °C compared to 18 °C, however, significantly reduced seahorse growth. A thermal tolerance polygon calculated as 302 °C 2 suggests that H. erectus has a wide tolerance to the extreme conditions commonly present in estuarine environments. Given that the amplitude in the thermal tolerance polygon was mainly due to an increase in the lower limits of the interval and that no minimum temperature threshold could be determined, thus suggesting that the populations from YP are near their upper thermal limit.
Ecological Indicators, 2019
H., Olivares, A., Diaz, F. and Rosas, C. (2017). Temperature modulates spatio-temporal variabilit... more H., Olivares, A., Diaz, F. and Rosas, C. (2017). Temperature modulates spatio-temporal variability of the functional reproductive maturation of Octopus maya (Cephalopoda) on the shelf of the Yucatan Peninsula, Mexico. J.
Ecological Indicators, 2017
Tropical populations of marine species are predicted to be the most impacted by global warming be... more Tropical populations of marine species are predicted to be the most impacted by global warming because they are likely adapted to a narrow range of temperatures in their local environment. In the present study, we investigated the thermal range at which activity metabolic rate (AMR) is maximal, pejus, and critical in the spiny lobster Panulirus argus using different ecophysiological biomarkers. Lobsters were acclimated at constant temperatures (18, 22, 26 and 30 • C; N = 150) at laboratory conditions for 35 days; after that time thermal biology was evaluated. Results obtained demonstrated that, in P. argus the temperature where AMR was maximal does not coincide with temperature that promotes the maximum growth rate (26 • C). In fact, the preferred temperature, determined in a horizontal gradient was around the mean value of 27.5 • C, 5.5 • C above the temperature where animals showed their maximum metabolic scope, growth and thermal preference. Lactate and redox imbalance showed its maximum values in animals acclimated at 30 • C indicating that lobsters where in pejus thermal ranges. Although lobsters are adapted to tolerate temperatures beyond 28 • C, results indicated that temperature and exposure time play important roles in the way organisms respond to thermal challenges. It is likely that the difference in the responses of different ectothermic organisms and the thermal response is linked to the way these effects are measured. These results can help generate predictive models to anticipate changes in the P. argus fishery derived from likely changes in distribution and abundance of this species under warming scenarios of tropical oceans.
Biology open, Jan 15, 2016
Optimum temperatures can be measured through aerobic scope, preferred temperatures or growth. A c... more Optimum temperatures can be measured through aerobic scope, preferred temperatures or growth. A complete thermal window, including optimum, transition (Pejus) and critical temperatures (CT), can be described if preferred temperatures and CT are defined. The crustacean Hemigrapsus crenulatus was used as a model species to evaluate the effect of acclimation temperature on: (i) thermal preference and width of thermal window, (ii) respiratory metabolism, and (iii) haemolymph proteins. Dependant on acclimation temperature, preferred temperature was between 11.8°C and 25.2°C while CT was found between a minimum of 2.7°C (CTmin) and a maximum of 35.9°C (CTmax). These data and data from tropical and temperate crustaceans were compared to examine the association between environmental temperature and thermal tolerance. Temperate species have a CTmax limit around 35°C that corresponded with the low CTmax limit of tropical species (34-36°C). Tropical species showed a CTmin limit around 9°C simi...
Ciencias Marinas, 2012
The phylogenic relationships among the Octopus species have not been fully established. We compar... more The phylogenic relationships among the Octopus species have not been fully established. We compared sequences for three mitochondrial genes (16S ribosomal RNA, cytochrome oxydase I, and cytochrome oxydase III) from Octopus maya, an endemic taxon of the Yucatan Peninsula, with homologous sequences from other taxa within the Octopus genus, with the aim of elucidating the phylogenetic relationships of this species. Maximum likelihood trees grouped O. maya with octopuses that inhabit the East Pacific. Considering that the distribution of O. maya is limited to the Yucatan peninsula in the West Atlantic and that the sequences analyzed show equal evolutionary rates across taxa, we propose that the divergence of O. maya possibly started during the formation of the Panama Isthmus, when the Pacific and Atlantic basins were split. The genetic distances that O. maya sequences show within the trees obtained are in the range of congeneric distances of other taxa in this genus so that these sequen...
Revista de biología tropical
In Campeche, Mexico, the Laguna de Términos has Thalassia testudinum beds inhabited by the grey s... more In Campeche, Mexico, the Laguna de Términos has Thalassia testudinum beds inhabited by the grey snapper, Lutjanus griseus (Linnaeus 1758). Along one year, we collected 994 individuals and 672 had food in their stomachs; we recorded number, weight, and frequency oftrophic groups, and the index of relative importance. Dominant food components were Farfantepenaeus duorarum and Palemonetes octaviae, Eucinostomus gula (Cuvier 1830) and Libinia dubia. Salinity and temperature were related to the number of individuals collected and with greater fish consumption by large L. griseus. The trophic niche breadth index was calculated for six size-classes of fish. The smallest and the largest fish had the lowest index values, whereas medium-size snappers had higher values. This snapper has a preference for habitats with submerged vegetation. The percentage of fish with food in their stomachs was higher during dark hours, providing evidence of the nocturnal habits of this fish.
Molluscan Research, 2017
The oviducal glands (ODG) play a crucial role in octopus reproduction. Herein, structural changes... more The oviducal glands (ODG) play a crucial role in octopus reproduction. Herein, structural changes of each section of the ODG of Octopus mimus are described histologically throughout the gonad development stages (GDS). To do this, the epithelial height, stereociliated or non-stereociliated epithelium, nucleus type (pycnotic or non-pycnotic), epithelial secretions and the value range of the macroscopic maturity index (MaMI), which directly involves ODG status, were measured. The ODG are internally constituted of two glandular units (central and peripheral glands) and one set of receptacles (the spermathecae). High epithelia (40 to 80 μm) were observed in both gland units during periods with low MaMI values (< 0.1) corresponding to III-mature and IV-pre-spawning. The stereociliated epithelium was only apparent in II-maturing and III-mature in both gland units. The nuclei were noticeably pycnotic in the central gland during III-mature, IV-pre-spawning and V-spawning, but pycnotic in the peripheral gland only during VI-depletion. The epithelium was disorganised during VI-depletion, while sulphated acid mucin was only present during III-mature in the central gland. The epithelium transformations during the GDS are related to the functions of the gland units and to their multiple secretions. The ODG histology complements the GDS and provides better reproductive status assessment.
Journal of Molluscan Studies, 2017
Laboratory studies have demonstrated that high temperatures inhibit spawning of Octopus maya; the... more Laboratory studies have demonstrated that high temperatures inhibit spawning of Octopus maya; therefore, in oceanic warming scenarios the population dynamics may be affected. The aim of the present study was to go beyond laboratory studies under controlled temperatures to examine the possible relationship between large-scale thermal patterns and reproductive season (represented by functional maturation) of O. maya in the wild on the continental shelf of the Yucatan Peninsula, where it is endemic. The macroscopic maturity index (MaMI) was obtained in females, and reproductive complex index (RCI) and number of spermatophores in males. Associations between these indices and environmental temperature regime were inferred by sampling octopuses in an upwelling zone (Z-I), a transition zone (Z-II) and a nonupwelling zone (Z-III). The reproductive condition of O. maya differed between Z-I and Z-III. In all zones, the proportion of adults showing functional maturity was highest in both females (MaMI: 36-71% of values ≤0.2) and males (RCI: 12-40% of values ≥0.9; 41-49 spermatophores per octopus) during the season of winter storms ('nortes' season, November-February), when the sea-surface temperature oscillates around 25°C. In Z-I, some individuals were functionally mature throughout the year, likely due to low temperatures maintained by summer upwelling. Zone-I had the greatest proportion of functionally mature males (up to 40% of adults in 'nortes' season) and the greatest number of spermatophores (mean 43-49 spermatophores per octopus in all seasons). Females in Z-III (without upwelling) were functionally mature mainly in the 'nortes' season when water temperature decreased, with only a small proportion mature in the rest of the year when water temperatures reached 31°C. As predicted by laboratory studies, water temperature below 27°C appears to be favourable for the functional reproductive maturation of wild O. maya.
Molluscan Research, 2016
ABSTRACT Octopus maya is the main species caught in Mexico. From September 2007 to June 2008, its... more ABSTRACT Octopus maya is the main species caught in Mexico. From September 2007 to June 2008, its sex ratio, reproductive season, frequency of non-vitellogenic and vitellogenic oocytes, reproductive indices, and size and weight at maturity, were evaluated. The monthly sex ratio was significantly different from 1:1. The major reproductive season occurs during February to June (dry season) in Yucatan. May−June is the common reproductive season to both Yucatán and Campeche populations. Higher frequencies of vitellogenic oocytes (> 50%) were found from January-March and in May. From five reproductive indices, only the macroscopic and microscopic maturity indices were the best descriptors of the reproductive season in females, whilst only the reproductive complex index was the best descriptor in males. The weight at sexual maturity (BW50%) was 335 g for females and 242 g for males. The size at sexual maturity (DML50%) was 12.58 cm for females and 7.42 cm for males. It is recommend revising the minimum catch size by following these results. The reproductive traits here evaluated could contribute to the recently created Plan for Management of Octopus Fisheries, in particular action line no. 1.4, which refers to protection of females during breeding, and to their protection throughout the entire reproductive season.
Frontiers in Physiology, 2020
Aquaculture, 2015
The present research showed, for the 1 st time, the effect of formulated diets for broodstock of ... more The present research showed, for the 1 st time, the effect of formulated diets for broodstock of O. maya. Reproductive response of Octopus maya females fed prepared diets and a control diet (crab) was evaluated according to reproductive performance and hatchling quality. Females were fed three formulated most diets based on: 1) crab and squid (CS), 2) crab, squid and fish heads (CSF) and 3) crab, squid and SELCO ® (CSS). Fresh crab (Callinectes sapidus) (Diet 4, C) was used as a control diet. A total of 10 females were used for each experimental diet (n=40). Females were fed 5% body weight d-1 until spawning. The feeding period of females was 50 days on average to natural spawning (p<0.05). Eggs laid by each female were placed in separate incubators with similar temperature, light and water quality, which were thoroughly controlled. Total egg number, egg batches, fecundity, spawning, newly hatched weight and survival after 10 days unfed were determined for each spawn. Eggs and hatchlings biochemical composition, as well as soluble protein content from the perivitelline were determined for each spawn. Embryonic development of eggs was also studied. No differences in reproductive performance were observed between the four diets. Contrary, PCO analysis showed marked differences on fatty acid composition of the yolk and hatchlings. Palmític acid (16:0) and araquidonic acid (20:4n6) were the main contributors for the first coordinate (eigen values, λ of 0.54 and 0.55 for embryo and hatchlings yolk, respectively). Females fed the control diet (C) produced hatchling with higher weight (p<0.05). Diet 3 (CSS) delivered the largest hatchlings (p<0.05) amongst the prepared diets. There were no differences (p>0.05) in soluble protein content of the perivitelline or newly hatched survival after 10 days unfed. Morphometric differences on 40 days old embryos were associated with females (p<0.05) but not with each diet (p>0.05). Results obtained indicate that O. maya female's present marked adaptation to the diets ingested prior to egg laying, without compromising reproductive performance.
Typhlatya is a genus of small, stygobitic shrimp in the family Atyidae. Phylogenic relationship o... more Typhlatya is a genus of small, stygobitic shrimp in the family Atyidae. Phylogenic relationship of a new population of Typhlatya discovered from Cenote Xtabay of the Ponderosa system, in Quintana Roo, is examined using H3 sequences. Results suggest that either it is a very closely related sister species to T. dzilamensis , with T. dzilamensis probably inhabiting the northern seacoast of Yucatan, and the new and undescribed species inhabiting the eastern seacoast. Alternatively, they are a single species with high morphologic variability, whose habitat encompasses the whole coastline of Yucatan.
Ecological Indicators, 2017
Abstract Most of our understanding on embryonic development in cephalopods comes from studies usi... more Abstract Most of our understanding on embryonic development in cephalopods comes from studies using constant temperature. Even though spawning generally occurs at relatively stable environments, eggs and embryos can be exposed over short periods of time to high temperature anomalies caused by oceanic warming. Therefore, in this study we examined the effects of increasing temperatures on growth, respiratory metabolism, and antioxidant defense mechanisms to define the thermal limits of Octopus maya embryos in a changing environment. Ramp temperatures consisted in increments of 1 °C every 5 days from 24 °C to 30 °C. The thermal limit of embryos at ramp temperatures was detected at 27 °C with metabolic rate increments between 63% and 69%, compared with the metabolic rate observed at control temperature (24 °C). Based on the calculated integrated biomarker response (IBR) was possible to detect that at the thermal limit, an increment on oxygen consumption was observed joint with reactive oxygen species (ROS). The IBR analysis indicated that above 27 °C embryos experienced changes in the oxidative system and were not able to recover. This study suggests that in a scenario of rapidly increasing temperatures after a short winter, O. maya embryos may suffer irreversible effects that are likely to negatively affect recruitment and the population dynamic. The thermal sensitivity of O. maya embryos, revealed in the present work, indicates that this species has an important potential for biomonitoring of the effects of environmental warming. Changes in the population dynamics of this species should be further studied since they can be used as a proxy for warming of the southern Gulf of Mexico ecosystems.
Journal of Thermal Biology, 2015
On the Yucatan Peninsula there is an upwelling which allows access to a body of cold water that c... more On the Yucatan Peninsula there is an upwelling which allows access to a body of cold water that controls temperature in this area. This modulates the ecology and distribution of organisms that inhabit the continental shelf. The objective of this study was to determine the effect of different acclimation temperatures on the thermal biology of prey as mollusc, crustacean (Melongena corona bispinosa, Strombus pugilis, Callinectes similis, Libinia dubia) and predators as fish (Ocyurus chrysurus, Centropomus undecimalis) of Octopus maya. Octopus prey preferred temperatures between 23.5°C and 26.0°C, while predators preferred temperatures 26.4-28.5°C. The species with largest thermal windows were M. corona bispinosa (328.8°C(2)), C. similis (322.8°C(2)), L. dubia (319.2°C(2)), C. undecimalis (288.6°C(2)), O. chrysurus (237.5°C(2)), while the smallest thermal window was for S. pugilis (202.0°C(2)). The acclimation response ratios (ARR) estimated for prey ranged from 0.24-0.55 in animals exposed to CTMax and 0.21-0.65 in those exposed to CTMin. Amongst predators, ARR ranged from 0.30 to 0.60 and 0.41 to 0.53 for animals exposed to CTMax and CTMin, respectively. Correlating the optimal temperature limits of prey and predators with surface temperatures on the continental shelf and those 4m deep showed that the main prey, Callinectes similis and L. dubia, shared a thermal niche and that an increase in temperature could force these species to migrate to other sites to find optimal temperatures for their physiological functions. As a consequence the continental shelf community would undergo a structural change. Predators were found to be near their optimal temperatures in surface temperatures on the continental shelf. We conclude that they would remain in the area in a warming scenario. The size of the thermal window was related to the type of ecosystem inhabited by these species. These ARR intervals allowed us to categorize the species as temperate or tropical, according to the oceanographic conditions that prevail on the Yucatan Peninsula.
ABSTRACT 26-29, Sept. 2009
Brasil. . 1302. TENDENCIAS DE LAS CAPTURAS DE CAMARÓN EN CENTROAMÉRICA. FABIO PAVAN PICCOLI, JULI... more Brasil. . 1302. TENDENCIAS DE LAS CAPTURAS DE CAMARÓN EN CENTROAMÉRICA. FABIO PAVAN PICCOLI, JULIO TOMÁS AQUIJES CHACALTANA. Brasil. 1323. Aspectos poblacionales del camarón-rosado, Farfantepenaeus brasiliensis y Farfantepenaeus paulensis (Decapoda, Penaeidae), en el estado del Rio de Janeiro, Brasil. A.P.P.; Parada, G. da Silva; Puciarelli, P; Bruno, R. da Rosa; Golodne, P. M.; Vianna, M. & Keunecke, K. A. Brasil. Jueves 29 de Octubre