Leopard Grouper Mycteroperca Rosacea Research Articles

Reproductive biology of the leopard grouper Mycteroperca rosacea (Streets, 1877) in the coastal area of Santa Rosalia, BCS, Mexico

The leopard grouper Mycteroperca rosacea is endemic to northwestern Mexico. It has been classified as vulnerable by the IUCN since 2008. M. rosacea has high commercial value and is caught yearround in Baja California Sur (BCS). Biological information on this species, especially in its natural environment, is scarce, and the objective of this study was to analyze its reproductive biology in Santa Rosalia, BCS. A total of 345 specimens were collected from March 2014 to May 2015. The sex ratio was 2.0: 1.0 (females: males, P < 0.05). Population size at first maturity (L 50 ) was estimated at 40.77 cm TL; 37.31 cm TL for males and 42.44 cm TL for females. Gonadic development was synchronous by group, with a reproductive period occurring from March to May in 2014 and 2015 (at 20-23oC). The gonadosomatic index achieved maximum values in May 2014 and March 2015, as did the highest frequencies of mature and spawning individuals, indicating that there was a clear seasonal pattern of reproduction, and a negative correlation with temperature for both sexes. The hepatosomatic index and the condition index indicated that M. rosacea is not a species that requires storing of energy for reproductive events, as it seems to have food available year-round. Normal 0 21 false false false ES X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:Tabla normal; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; line-height:115%; mso-pagination:widow-orphan; font-size:12.0pt; mso-bidi-font-size:11.0pt; font-family:Times New Roman,serif; mso-bidi-font-family:Times New Roman; mso-bidi-theme-font:minor-bidi; mso-ansi-language:ES; mso-fareast-language:EN-US;}

Reproductive cycle of leopard grouper Mycteroperca rosacea (Streets, 1877) held in captivity: relation ship between gonad development and sex steroid concentration

In this study, sex steroids (E2, T, and 11-KT) concentrations in blood of captive leopard grouper ( Mycteroperca rosacea ) and their relation togonad development were determined during a reproductive cycle. Each month, gonad samples from 24 fish were obtained to analyze gonadal maturation and blood was extracted to determine steroid levels. Throughout the year, ovaries showed a higher percentageof primary oocytes. In January, oocytes at early and late vitellogenesis stages increased progressively; from March to June, ovulation rates were high. In females, estradiol levels increased from March and decreased after the spawning season. Lower levels of testosterone were found during the spawning season and 11-KT remained without significant changes throughout the year. Males exhibit a significant increase in E2 from March until July; testosterone remained without significant variation throughout theyear, and 11-KT plasma levels increased from March until July and decreased after the spawning season. In this study, we verified the sex change of an organism and the concentrations of sexual steroids were determined and discussed.

Social factors and aromatase gene expression during adult male-to-female sex change in captive leopard grouper Mycteroperca rosacea

Social factors and aromatase gene expression in the leopard grouper Mycteroperca rosacea was studied when captive fish were separated by sex during the reproductive (April–June) and post-reproductive (July–September) seasons. Monosex females, monosex males, and mixed-sex, held in social sextet units were analyzed for sex steroids throughout confinement. At the end of the experiment, the gonad-sex was defined by histology, and gonad and brain aromatase gene expressions were quantified. Only males held in the monosex social units changed sex. Histology showed one male remained unchanged, six were found in a transitional sexual stage, in which two had intersex-predominantly-testes, and four had a more defined intersex ovo-testes pattern, and 11 were immature de novo females (neofemales). Neofemales and most intersex fish did not survive. In spring, 11-ketosterone showed a specific male profile, which suggests that male-to-female sex change was not triggered during the reproductive season. The low steroid levels in summer made it impossible to associate the sex change to a gonad hormonal shift; in September, gonad aromatase gene expression was not significantly different among groups. However, brain aromatase expression in intersex fish was significantly higher than monosex females, mixed-sex females, and neofemale groups. These results suggest that in the absence of female hormonal compounds, and at a time when male gonad steroidogenesis was diminished, the brain mediated male-to-male social-behavioral interactions, including stress, by increasing aromatization, resulting in derived intersex-male, which triggered more aromatization, followed by a sex change.

Incidence of xanthism in the leopard grouper Mycteroperca rosacea (Perciformes: Serranidae) in the Gulf of California

Five leopard grouper Mycteroperca rosacea specimens were captured in the Gulf of California, two of which presented a rare orange pigmentation on both sides of the body. The remaining individuals presented changes to the normal pigmentation pattern on the left or right flanks. The possible causes of these phenomena are discussed.

Simultaneous Germinal Vesicle Migration and Oil Droplet Coalescence Predict Final Oocyte Maturation in the Leopard Grouper

AbstractThe size of oocytes during germinal vesicle migration (GVM) and germinal vesicle breakdown (GVBD) was revised for the Leopard Grouper Mycteroperca rosacea. Histology of ovaries, plasma levels of estradiol‐17ß (E2), and testosterone (T) were analyzed in Leopard Grouper at 0, 12, 16, and 24 h after a priming dose of 1,000 IU/kg body weight of human chorionic gonadotropin (hCG) and were compared with control females injected with saline solution. Histological observations were verified in hormonally induced females by observing in vivo intraovarian biopsies after using the same priming dose and a second resolving dose of 500 UI/kg body weight of hCG 16 or 24 h later, which served to analyze spawning performance. Histological and in vivo intraovarian biopsies showed that in full‐yolk oocytes (~455 μm diameter) GVM and GVBD were concomitant with coalescence of a single oil droplet 16 and 24 h after the first injection. The oil droplet became a morphological marker as well as a predicting indicator of the competence and synchronization of maximum vitellogenic oocytes and the effectiveness to respond to hormonal therapy. In the experimental fish group E2 and T reached peaks at the same time, which were significantly higher than those in the controls. Mean fecundity was 168,000 eggs/kg, mean fertilization was 88%, and mean viability was 71% (114,000 eggs/kg), all of which were within the range of other cultivated groupers. These results can be used to improve the induction of final maturation in the Leopard Grouper in captivity and may be used in other species of Mycteroperca that show the same marker.

Asymmetric connectivity of spawning aggregations of a commercially important marine fish using a multidisciplinary approach.

Understanding patterns of larval dispersal is key in determining whether no-take marine reserves are self-sustaining, what will be protected inside reserves and where the benefits of reserves will be observed. We followed a multidisciplinary approach that merged detailed descriptions of fishing zones and spawning time at 17 sites distributed in the Midriff Island region of the Gulf of California with a biophysical oceanographic model that simulated larval transport at Pelagic Larval Duration (PLD) 14, 21 and 28 days for the most common and targeted predatory reef fish, (leopard grouper Mycteroperca rosacea). We tested the hypothesis that source–sink larval metapopulation dynamics describing the direction and frequency of larval dispersal according to an oceanographic model can help to explain empirical genetic data. We described modeled metapopulation dynamics using graph theory and employed empirical sequence data from a subset of 11 sites at two mitochondrial genes to verify the model predictions based on patterns of genetic diversity within sites and genetic structure between sites. We employed a population graph describing a network of genetic relationships among sites and contrasted it against modeled networks. While our results failed to explain genetic diversity within sites, they confirmed that ocean models summarized via graph and adjacency distances over modeled networks can explain seemingly chaotic patterns of genetic structure between sites. Empirical and modeled networks showed significant similarities in the clustering coefficients of each site and adjacency matrices between sites. Most of the connectivity patterns observed towards downstream sites (Sonora coast) were strictly asymmetric, while those between upstream sites (Baja and the Midriffs) were symmetric. The best-supported gene flow model and analyses of modularity of the modeled networks confirmed a pulse of larvae from the Baja Peninsula, across the Midriff Island region and towards the Sonoran coastline that acts like a larval sink, in agreement with the cyclonic gyre (anti-clockwise) present at the peak of spawning (May–June). Our approach provided a mechanistic explanation of the location of fishing zones: most of the largest areas where fishing takes place seem to be sustained simultaneously by high levels of local retention, contribution of larvae from upstream sites and oceanographic patterns that concentrate larval density from all over the region. The general asymmetry in marine connectivity observed highlights that benefits from reserves are biased towards particular directions, that no-take areas need to be located upstream of targeted fishing zones, and that some fishing localities might not directly benefit from avoiding fishing within reserves located adjacent to their communities. We discuss the implications of marine connectivity for the current network of marine protected areas and no-take zones, and identify ways of improving it.

Isolation and characterization of fifteen microsatellite loci in Leopard grouper (Mycteroperca rosacea) via 454 pyrosequencing

Leopard grouper (Mycteroperca rosacea) are distributed from Bahia Magdalena, through the Gulf of California and as far south as Jalisco, Mexico. They are listed as Vulnerable on the IUCN Red List due to significant fishing-induced declines over the past decade. Microsatellite loci were isolated by constructing a shotgun genomic library and sequencing using 454 XL + titanium chemistry. We characterized 15 polymorphic loci in 120 samples from three geographic locations. Genotyping yielded 15–60 alleles per locus with observed levels of heterozygosity ranging from 0.575 to 0.975.

Leukophilia during maturation of the leopard grouper Mycteroperca rosacea

In spring, peripheral blood of mature-ripe female leopard groupers showed leukophilia after an increase of lymphocytes and thrombocytes, followed by a differential increase of monocytes and granulocytes. In mature-ripe males, granulophilia and thrombophilia were evident. Leukocytes were distinguishable in some ovarian blood vessels where post-ovulatory follicles were present. These observations suggest coordination of endocrine-immune activity, where, after one spawning event, leukocytes infiltrate the gonad tissue from the peripheral blood to aid with immune surveillance and phagocyte activity, while a feedback of sex steroids and vitellogenesis occurs in preparation for the next spawning. An abundance of leukocytes may also aid in gonad reabsorption during post-spawning. Leukophilia coincided with high plasma concentrations of oestradiol and testosterone, which together with leukocytes, decreased greatly in immature-active groupers in summer. Blood cell counts, erythroblasts, and haematocrit of mature-ripe groupers in spring were significantly lower than immature-active groupers in summer, suggesting mild anorexia induced by reproductive behaviour.

Reproductive cycle of the leopard grouper Mycteroperca rosacea in La Paz Bay, Mexico

The leopard grouper Mycteroperca rosacea is an endemic species from the northwestern coast of Mexico and, like other serranid fishes, it has a high commercial value; hence, it is a good candidate for cultivation. This study aimed to describe the reproductive cycle of the leopard grouper in the wild as a step toward evaluating its aquaculture and restocking potential. From March 2008 to February 2009, 197 specimens were collected in the Gulf of California, Mexico. Overall sex ratio was 3.6 females to 1.0 male. Significant differences (P &lt; 0.05) in total length and body weight were found between sexes. Group-synchronous ovarian development was observed with one yearly spawning period from May to June. Males matured two months earlier than females. The reproductive cycle was divided into four periods: (1) maturation, (2) spawning, (3) post-spawning, and (4) resting. Significant variations in the gonadosomatic index, hepatosomatic index, visceral fat index, and condition factor were observed throughout the study period. In addition, nine individuals were classified as immature bisexuals and one grouper presented evidence of sex change.

Effects of dietary supplementation with probiotic live yeast Debaryomyces hansenii on the immune and antioxidant systems of leopard grouper Mycteroperca rosacea infected with Aeromonas hydrophila

Two trials were conducted to determine the e⁄cacy of ¢sh fed live yeast Debaryomyces hansenii strain CBS 8339 on immune and antioxidant systems in leopard grouper Mycteroperca rosacea infected with Aeromonas hydrophila .J uveniles (12� 0.5 g) were fed with a control diet or a D. hansenii-supplemented diet (10 6 colony-forming units per gram) for 5 weeks. The live weight of ¢sh was registered on a weekly basis. After 4 weeks, ¢sh from each treatment were immunocompromised with pathogenic A. hydrophila and further fed for1week in order to evaluate the eiect on immunological and antioxidant parameters. Generally, the results showed enhanced growth performance in ¢sh fed the diet containing yeast compared with the control. Addition of live yeast had no signi¢cant eiect on the immunological parameters after 4 weeks of feeding. However, post infection with A. hydrophila ¢sh fed the yeast-supplemented diet resulted in a signi¢cant increase in the levels of plasmatic immunoglobulin M. Superoxide dismutase and catalase (CAT) activities were signi¢cantly higher in the yeast group. In this ¢sh, CAT and heat shock protein 70 genes were up-regulated before and after infection of A. hydrophila. The present study is the ¢rst one reporting that yeast (D. hansenii) can enhance immunity and resistance against A. hydrophila.

Description of peripheral blood cells and differential blood analysis of captive female and male leopard grouper Mycteroperca rosacea as an approach for diagnosing diseases

The peripheral blood cells and differential blood profile of captive female and male leopard grouper Mycteroperca rosacea are described for aquacultural purposes. Basophilic, polychromatic, and orthochromic erythroblasts were observed as immature erythrocytes that develop into mature erythrocytes. Young erythrocytes were not evident, and bi-lobed erythrocytes were extremely scarce. Types of leukocytes included lymphocytes; three types of granulocytes (basophiles, eosinophiles, and neutrophiles); monocytes; and a specialized amoeboid-like macrophage in the blood, which has not been previously described in fish-blood literature. Thrombocytes were commonly observed. There was significantly higher erythropoiesis in males. Granulocytes and lymphocytes of females were significantly higher than males, whereas monocytes and thrombocytes were not.

Morphological development and growth patterns of the leopard grouper Mycteroperca rosacea during larval development

At 25 °C, metamorphosis in leopard grouper Mycteroperca rosacea larvae took 60 days after hatching. The total length at day 1 was 1.95±0.22 mm and juveniles reached a length of 30.64±0.23 mm at day 60; the increase was approximately linear. We describe eight stages of development during this period. Larvae with the yolk sac attached occur from days 1 to 4 (Stages 1 and 2). The preflexion occurs on days 5–20 (Stages 3 and 4). Bending notochord occurred at day 25 (Stage 5). The other morphological changes that precede the juvenile phase occurred progressively until day 60 (Stages 6–8). Allometric growth in the height and length of the head, trunk length, height and length of the tail and the diameter of the eye compared with the total length showed two distinct stages of growth. Inflexion point, where growth is positive, occurred when larvae reached between 18.75 and 21.59 mm, which corresponds to larvae at days 35–40.

Effects of dietary live yeast Debaryomyces hansenii on the immune and antioxidant system in juvenile leopard grouper Mycteroperca rosacea exposed to stress

This study investigated the effects of the dietary intake of live yeast Debaryomyces hansenii (CBS 8339) on the immune response of juvenile leopard groupers Mycteroperca rosacea and on their resistance to infection by dinoflagellates Amyloodinium ocellatum.During 4 weeks, juvenile groupers were fed either a diet supplemented with D. hansenii at 106 cfu g−1 or a control diet. Both groups were then transferred to a system infected with A. ocellatum and maintained in this stressful environment, for one week. Rearing conditions were favorable to the proliferation of the dinoflagellate and, at 7 days post-infection, the cumulative mortality rate of the control group was 89.5%, suggesting that the yeast-enriched diet conferred protection against the parasite. Only fish with yeast-supplemented diet recovered from the A. ocellatum challenge.The immunological response of both groups of fish was evaluated. Samples were collected at weeks 4 (stressed fish) and 7 (recovering fish) to determine the levels of hemoglobin, plasmatic protein, and immunoglobulin M (IgM) as well as the activity of antioxidant enzymes (SOD and CAT). IgM increased significantly (P≤0.05) in the recovering fish, which had all been fed the yeast diet. A significantly increase was also observed in superoxide dismutase activity in juvenile fish fed the yeast diet; however catalase activity was not affected by the dietary yeast supplement. Overall, fish that received the yeast supplement in their diet have an enhanced immune response as compared with their control counterparts. The present results show that a diet supplemented with D. hansenii stimulates the immune system of juvenile M. rosacea thus enhancing their resistance against A. ocellatum.

Effects of temperature and salinity on artificially reproduced eggs and larvae of the leopard grouper Mycteroperca rosacea

The effects of temperature and salinity on eggs and larvae of the leopard grouper, Mycteroperca rosacea, were studied. Eggs from hormone-induced spawning were artificially fertilized. The effect of temperature (20, 24, 26, 28, and 30 °C) on hatch rate, notochord length, yolk sac volume, and oil droplet diameter was recorded. Times from fertilization to 50% hatch and hatching period duration (first to last hatch) were also recorded for each temperature. The effect of temperature (20, 24, 26, and 28 °C) on survival, growth rate, and final larval lengths 5 days after fertilization was demonstrated. The effect of salinity (0‰, 8‰, 16‰, 24‰, 32‰, 40‰, 48‰, 56‰, and 64‰) on hatching rate and larval lengths at hatch was recorded. Additionally, the effect of salinity (0‰, 10‰, 20‰, 30‰, and 40‰) on survival and growth of larvae until total absorption of the yolk sac was demonstrated. Also, egg buoyancy at different salinities was established. Results indicate better hatching rates (70–78%) in temperatures ranging from 24 to 30 °C than at 20 °C. The notochord length of newly hatched larvae was inversely related to temperature and to the oil droplet diameter. Larvae that hatched at 20 °C were the longest and had the smallest oil droplet diameters and yolk sac volumes. The largest yolk sac volumes were observed at 26 and 28 °C. Times from fertilization to 50% hatch and hatching period duration decreased with increasing temperature. A higher larval growth rate to day 5 after fertilization was obtained at higher temperatures. Eggs maintained at 32‰ salinity showed the best hatching rates (80.7%). In the salinity growth trial, final notochord lengths of the larvae were inversely related to salinity. Eggs were buoyant at salinities above 34‰.