Captive parturition and neonatal growth of the dwarf ornate wobbegong (Orectolobus ornatus de Vis, 1883).

Neonatal predation in multispecies aquarium exhibits can prevent detection of captive breeding by wobbegong sharks. We used ultrasonography and isolation strategies to prevent neonatal predation and maximize survival/growth of the dwarf ornate wobbegong (Orectolobus ornatus de Vis, 1883). We captured seven free-living wobbegongs (two males and five females) and subjected each animal to a health assessment which led to the euthanasia of one female with a retained hook. Ultrasonography showed that females were pregnant, one was preovulatory, and one was in a resting phase. Two females (one pregnant) and one male were placed in isolation in each of two tanks. In October 2006, 25 neonates were born overnight with the two litters placed into separate neonate tanks. Over the ∼6.5-month monitoring period, four neonates with reduced body condition died without premonitory signs resulting in a 63.0% annual survival rate. Finite growth rates did not differ between sexes or litters and averaged (±SE) 12.2 (1.5) cm/year and 156.4 (26.4) g/year. At the cessation of monitoring, total length had increased by ∼30%, whereas total weight had almost doubled with neonatal body condition in line with free-living wobbegongs. Our efficacious, six-step manipulative, the approach should be applicable with all wobbegongs given their reproductive similarities, but we recommend that efforts focus on the dwarf ornate, tasselled and Japanese wobbegongs because all are small in size and have bred in aquaria. Ultimately, this approach should produce self-sustaining aquarium populations, place less reliance on the wild acquisition and provide animals for other aquaria, population restocking, or scientific research.

Structural changes to the uterus of the dwarf ornate wobbegong shark (Orectolobus ornatus) during pregnancy.

Embryos of the viviparous dwarf ornate wobbegong shark (Orectolobus ornatus) develop without a placenta, unattached to the uterine wall of their mother. Here, we present the first light microscopy study of the uterus of O. ornatus throughout pregnancy. At the beginning of pregnancy, the uterine luminal epithelium and underlying connective tissue become folded to form uterine ridges. By mid to late pregnancy, the luminal surface is extensively folded and long luminal uterine villi are abundant. Compared to the nonpregnant uterus, uterine vasculature is increased during pregnancy. Additionally, as pregnancy progresses the uterine epithelium is attenuated so that there is minimal uterine tissue separating large maternal blood vessels from the fluid that surrounds developing embryos. We conclude that the uterus of O. ornatus undergoes an extensive morphological transformation during pregnancy. These uterine modifications likely support developing embryos via embryonic respiratory gas exchange, waste removal, water balance, and mineral transfer.

The Role of Herbivory in Structuring Tropical Seagrass Ecosystem Service Delivery.

Seagrass meadows support key ecosystem services, via provision of food directly for herbivores, and indirectly to their predators. The importance of herbivores in seagrass meadows has been well-documented, but the links between food webs and ecosystem services in seagrass meadows have not previously been made explicit. Herbivores interact with ecosystem services - including carbon sequestration, cultural values, and coastal protection. Interactions can be positive or negative and depend on a range of factors including the herbivore identity and the grazing type and intensity. There can be unintended consequences from management actions based on a poor understanding of trade-offs that occur with complex seagrass-herbivore interactions. Tropical seagrass meadows support a diversity of grazers spanning the meso-, macro-, and megaherbivore scales. We present a conceptual model to describe how multiple ecosystem services are influenced by herbivore pressure in tropical seagrass meadows. Our model suggests that a balanced ecosystem, incorporating both seagrass and herbivore diversity, is likely to sustain the broadest range of ecosystem services. Our framework suggests the pathway to achieve desired ecosystem services outcomes requires knowledge on four key areas: (1) how size classes of herbivores interact to structure seagrass; (2) desired community and management values; (3) seagrass responses to top-down and bottom-up controls; (4) the pathway from intermediate to final ecosystem services and human benefits. We suggest research should be directed to these areas. Herbivory is a major structuring influence in tropical seagrass systems and needs to be considered for effective management of these critical habitats and their services.

Serum biochemical reference intervals for wild dwarf ornate wobbegong sharks (Orectolobus ornatus).

BACKGROUND: Sharks are important to sport and commercial fishing, public aquaria, and research institutions. However, serum biochemical reference values have been established for few species. OBJECTIVE: The aim of this study was to establish serum biochemical reference intervals for wild-caught dwarf ornate wobbegong sharks (Orectolobus ornatus). METHODS: Fifty wobbegongs were caught, and their health status, sex, length, and weight were evaluated and recorded. Following collection of blood, serum biochemical analytes were measured and analyzed using standard analytical and statistical methods. Combined samples generated means, medians, and reference intervals. RESULTS: For the measured analytes, means (reference intervals) were as follows: sodium 287 (284-289) mmol/L, chloride 277 (274-280) mmol/L, potassium 5.2 (5.0-5.3) mmol/L, total calcium 4.6 (4.5-4.7) mmol/L, magnesium 1.9 (1.7-2.0) mmol/L, inorganic phosphate 1.8 (1.7-1.9) mmol/L, glucose 2.6 (2.4-2.8) mmol/L, total protein 46 (45-47) g/L, urea 396 (392-401) mmol/L, creatinine ≤ 0.02 mmol/L, total bilirubin 2.0 (1.9-2.1) µmol/L, cholesterol 1.3 (1.2-1.4) mmol/L, triglyceride 0.5 (0.4-0.6) mmol/L, alkaline phosphatase 24 (21-28) U/L, alanine aminotransferase 3 U/L, aspartate aminotransferase 28 (25-31) U/L, creatine kinase 49 (38-59) U/L, and osmolarity 1104 (1094-1114) mmol/L. Serum values were not affected by sex, length, or weight. CONCLUSIONS: Established reference values will assist with clinical evaluation and treatment of dwarf ornate wobbegongs in aquaria, research institutions, and the wild.