Tourism and Marine Wildlife: The Wild Dolphins of Tangalooma,Australia: A Case Report

Abstract

Tourist interest in experiencing marine wildlife in their natural environment is growing. In particular, opportunities for interaction with marine mammals such as dolphins are becoming increasingly popular. Such interaction between humans and solitary dolphins has occurred throughout history; however, the dolphins at Monkey Mia in Western Australia are the only recorded group of dolphins which regularly interact with tourists. A previously unreported case of tourist-dolphin interaction is being developed at Tangalooma in Queensland, Australia. The development of this program is outlined in this paper and the current management of this interaction is considered.     

REDUCING INCIDENTAL MORTALITY OF FRANCISCANA DOLPHIN PONTOPORIA BLAINVILLEI WITH ACOUSTIC WARNING DEVICES ATTACHED TO FISHING NETS

We conducted a double blind experiment in an artisanal gillnet fishery in Argentina to determine the effectiveness of acoustic deterrents (pingers) at reducing bycatch of the Franciscana dolphin ( Pontoporia blainvillei ). The fishery was conducted by small inflatable and fiberglass vessels operating between 0.5 and 7 krn from the coast. Each vessel carried an independent observer who was rotated from vessel to vessel throughout the course of the experiment. Information on the number of dolphins captured, geographic position, depth, configuration of fishing gear, soak time, biomass of fish caught, and sea lion predation in a string/net producing any damage was recorded. Equivalent numbers of active and silent pingers were used during the experiment. A total of 45 dolphins were caught in the silent nets, and seven were caught in the active pinger nets, demonstrating a highly significant reduction in bycatch for this species. However, sea-lions ( Otaria flavescens ) damaged the fish in active pinger nets significantly more than silent nets, and the damage increased over the course of the experiment. Although pingers show promise as a management tool for this species, pinniped depredation suggests that higher pinger frequencies will be needed to avoid a "dinner bell" effect.     

Adaptation of molecular genetic methods to study microorganisms associated with fish

A modern molecular genetic method has been adapted to study microorganisms associated with fish. A procedure for total DNA isolation from various organs and tissues of fish has been developed. Besides fish freshly caught, frozen and salted specimens were used. A bacterial PCR product was shown to amplify with highly conservative primers at an annealing temperature of 70–72°C from fish gills, liver, intestine, and skin.     

A simple method of feeding coregonid larvae on frozen zooplankton

7 days old larvae of Coregonus lavaretus L. (local name: ‘Blaufelchen’) were fed on zooplankton that had been frozen at—18°C for 1 year. 4 times per day the pieces of frozen plankton were added into the preaeration tank thus providing that freshly thawed zooplankters were offered to the fish. Within 10 weeks the fish reached a total length of 30.5 ± 5.5 ram and an average dry weight of 22 mg. Within this period the survival was 45 % of the initial number. After a period of 7 weeks feeding on long-term frozen pankton 400 fish were switched to living zooplankton and after 9 weeks 400 fish were switched to short-term frozen plankton. The growth of those fish that were fed on living plankton was significantly faster than it was when frozen zooplankton was given. A switch of coregonids which were prefed on frozen zooplankton to dry diet proved to be successful as soon as the fish had reached a body length of 40 mm.     

A comparison of pectoral fin contact behaviour for three distinct dolphin populations

Tactile exchanges involving the pectoral fin have been documented in a variety of dolphin species. Several functions (e.g., social, hygienic) have been offered as possible explanations for when and why dolphins exchange pectoral fin contacts. In this study, we compared pectoral fin contact between dolphin dyads from three distinct dolphin populations: two groups of wild dolphins; Atlantic spotted dolphins (Stenella frontalis) from The Bahamas and Indo-Pacific bottlenose dolphins (Tursiops aduncus) from around Mikura Island, Japan; and one group of captive bottlenose dolphins (Tursiops truncatus) residing at the Roatan Institute for Marine Sciences, Anthony's Key Resort. A number of similarities were observed between the captive and wild groups, including; rates of pectoral fin contact, which dolphin initiated contact, posture preference, and same-sex rubbing partner preference. Unlike their wild counterparts, however, dolphins in the captive study group engaged in petting and rubbing at equal rates, females were more likely to contact males, males assumed the various rubbing roles more frequently than females, and calves and juveniles were more likely to be involved in pectoral fin contact exchanges. These results suggest that some aspects of pectoral fin contact behaviour might be common to many dolphin species, whereas other aspects could be species specific, or could be the result of differing environmental and social conditions.     

Orangutans' color preference for food items

The effects of the addition of color to a dry primate diet on the feeding behavior of orangutans were studied. Purina Monkey Chow was dipped in food coloring (red, green, blue, orange). Colored and plain chow was offered to the subjects, three adults, and two juveniles. Time to eat or lose interest in feeding, quantity, and color of pieces of chow handled and eaten were recorded for each group. The juveniles' consumption of chow increased when offered colored chow, and adults required less time to consume their food. One juvenile showed a significant preference for red monkey chow.     

The protective immune response of yellowtail Seriola quinqueradiata to the bacterial fish pathogen Lactococcus garvieae.

Yellowtail Seriola quinqueradiata were immunized with 2 different Lactococcus garvieae bacterin, formalin-killed KG- phenotype cells (capsulated phenotype) and formalin-killed KG+ phenotype cells (unencapsulated phenotype). These 2 injected vaccines conferred long-term protection to yellowtail against an artificial infection of an encapsulated Lactococcus garvieae strain with long-lasting agglutinating titres against KG+ phenotype cells. However, no agglutinating titres or low agglutinating titres against KG- phenotype cells were detected in fish given each of these bacterin. These results suggested that a capsule in KG- phenotype cells apparently affects their immunogenicity, but the antigens which conferred protection to fish against lactococcal infection may be located on the surface of KG+ phenotype cells, and are not cell capsules in KG- phenotype cells. The protection offered by a formalin-killed KG+ phenotype cell vaccine would not appear to be strain specific. Encapsulated L. garvieae cells were well phagocytosed, and fimbrie-like appendages were seen in KG- phenotype cells after treatment with yellowtail immune serum.     

Extreme boldness precedes starvation mortality in six-lined trumpeter (<Emphasis Type="Italic">Pelates</Emphasis> <Emphasis Type="Italic">sexlineatus</Emphasis>)

Fishes are often subjected to seasonal and spatial patchiness of food sources. We tested how risk-taking behaviour in the six-lined trumpeter, an estuarine seagrass resident fish, changed with hunger level in a laboratory experiment. When repeatedly offered a risky source of food, well-fed fish did not approach it and all fish survived over a one-month trial. In contrast, fish deprived of all food boldly first approached the risky food source after only a few days without food in some cases, or after many days in other cases, and then continued to approach risky food each time it was presented. Larger individuals were more bold (and had longer starvation endurance) than smaller ones, and after statistically controlling for these size effects, there were consistent individual differences in the propensity to take risks (i.e. boldness). These results show that food- and individual-dependent boldness will together affect vulnerability to predators and influence predation rates when resources become scarce.     

Color patterns in white‐beaked dolphins (Lagenorhynchus albirostris) from Iceland

Few studies have examined the natural complex pigmentation patterns of white‐beaked dolphins. From 2002 to 2014, whale‐watching trips in Iceland provided a platform of opportunity to collect a large body of photographs of free‐ranging individuals from a single area of distribution for this species. Based on 823 images, 571 individuals showing one or more color components were identified, and assigned to the following four age classes: adults (n = 437), juveniles (n = 109), calves (n = 14), and neonates (n = 11). A total of 26 color components were observed and described: seven terms previously applied to white‐beaked dolphins, 12 previously applied to other dolphin species, and seven newly defined terms. Results showed that each age class could be positively identified by differences in specific color components, some of which were exclusive. Therefore, color patterns may prove useful in estimating maturity in free‐ranging white‐beaked dolphins. This tool could be further refined through assessment of a wide sample of freshly stranded specimens of known sex and age, which could reveal new age class‐specific components, as well as sexually dimorphic characteristics not seen here. Geographic variation should be investigated by comparing image data sets and stranded animals from different parts of the North Atlantic.     

Spatial and temporal distribution of whiting (Sillaginidae) in Moreton Bay, Queensland

Five species of whiting (Sillaginidae) inhabit Moreton Bay. The school whiting, Sillago bassensis , and stout whiting, S. robusta , are rare, caught occasionally by trawlers in areas of sandy substrates. The sand whiting, S. ciliata , golden-lined whiting, S. analis , and trumpeter whiting, S. maculata , are very common throughout the year. Sillago maculata is distributed almost throughout Moreton Bay, from 1 to 30 m depth. Sillago ciliata and S. analis are shallow water dwellers, from the shoreline to 3 m and 5 m depth, respectively. In the shallow waters, S. ciliata prefers the sandy substrates and S. analis the mud-sandy substrates. Distributions related to the depth, habitat preference, juvenile-adult grounds, food availability, interspecific competition, and winter season are discussed.     

Examination of naturally exposed bottlenose dolphins (Tursiops truncatus) for Microsporidia, Cryptosporidium, and Giardia

Bottlenose dolphins (Tursiops truncatus) captured in the estuarine waters off the coasts of South Carolina and Florida were examined for the presence of Microsporidia, Cryptosporidium sp., and Giardia sp. DNA extracted from feces or rectal swabs was amplified by polymerase chain reaction using parasite-specific small subunit ribosomal RNA gene primers. All positive specimens were subjected to gene sequence analysis. Of 83 dolphins, 17 were positive for Microsporidia. None was positive for Cryptosporidium or Giardia. Gene sequence data for each of the positive specimens were compared with data in GenBank. Fourteen specimens were found similar to, but not identical to, the microsporidian species Kabatana takedai, Tetramicra brevifilum, and Microgemma tinca, reported from fish, and possibly represent parasites of fish eaten by dolphins. Gene sequence data from 3 other specimens had approximately 87% similarity to Enterocytozoon bieneusi, a species known primarily to infect humans and a variety of terrestrial mammals, including livestock, companion animals, and wildlife. It is not clear if these specimens represent a species from a terrestrial source or a closely related species unique to dolphins. There were neither clinical signs nor age- or gender-related patterns apparent with the presence of these organisms.     

Fish use of an inundated saltmarsh flat in a temperate Australian estuary

Abstract Fish associated with Australian saltmarshes have previously been sampled from within creeks or semi-permanent pools on the marsh; this is the first record of fish use of marsh flats inundated on high tides but emergent on low tides. Buoyant pop nets (9 m², 1 mm mesh) were used to collect fish from two areas of the marsh flat on Torrens Island in the Barker Inlet-Port River estuary. South Australia. Fyke nets of the same mesh size were used to collect fish from small creeks draining the marsh flat. Fish were caught in only four of 48 pop net releases, for a total of 19 fish of two species (families Gobiidae and Atherinidae). A total of 1109 fish from six species were caught in creeks draining the same areas, and the two species caught on the flats were the most common species in the creeks. Economically important species were poorly represented, with just four specimens of the mugilid Aldrichetta forsteri (Valenciennes).     

Diagnostic polymerase chain reaction assay to detect Kudoa neurophila (Myxozoa: Multivalvulida) in a marine finfish hatchery

A single-round polymerase chain reaction (PCR) diagnostic assay was developed from a small subunit ribosomal DNA (SSU rDNA) gene sequence to detect the myxozoan parasite Kudoa neurophila, the causative agent of myxozoan disease in the hatchery reared marine finfish, striped trumpeter Latris lineata (Forster). The assay was developed for use as a disease control management tool in a hatchery system specifically designed to research and produce marine finfish such as striped trumpeter juveniles for aquaculture. The assay is sufficiently species specific and sensitive enough to detect a small fragment of the parasite's SSU rDNA. At the lower limits of detection, the test is consistently positive to an estimated 0.1 spore or 60 fg of parasite DNA per 25 microl PCR reaction in serial dilution and positive to an estimated 0.1 spore in 25 mg of infected fish CNS tissue (4 spores g(-1). Specifically, the test is capable of detecting early stages of the life cycle within the fish host and consequently diagnosing an infection not normally detected using traditional histological techniques. The test is also effective for screening water supplies and prey species cultures throughout the hatchery system to determine bio-security efficacy, to assist in identification of an alternate or other primary fish host, to indicate the location of potential disease reservoirs, and to enable a targetted approach to disease prevention.     

Formation of vitamin A in a freshwater fish. Isolation of retinoic acid.

The intestines of freshly caught Saccobranchus fossilis (a freshwater fish that contains dehydroretinol) became free from carotenoids and from vitamin A when the fish were starved for about 20 days. When beta-carotene was administered to such fish, retinoic acid could be isolated from the intestines after approx. 4h. When lutein was administered to such fish, dehydroretinol and 3-hydroxyretinol could be isolated from the intestines after approx. 5h.     

Behavior of dolphins towards adults and children during swim-with-dolphin programs and towards children with disabilities during therapy sessions

Abstract

In recent years, dolphin-assisted therapy has become very popular and an increasing number of facilities worldwide offer therapy programs with dolphins. In contrast to other animal-assisted therapy programs, dolphins are not domestic animals; they are mostly caught in the wild and there are still no studies on their behavior during these therapies. However, there is speculation that the behavior of dolphins toward people with mental and physical disabilities may play an important role in the success of the therapy. We observed 83 sessions with five untrained dolphins (Tursiops truncatus) at Dolphins Plus, a fenced area with ocean water in the Florida Keys, USA. Our detailed observations of contact and distance behavior between dolphins and different groups of swimmers (adults, children, and children with mental and physical disabilities) show that, in general, dolphins prefer small humans to adults. One dolphin showed a clear preference toward children with mental and physical disabilities, and we conclude that she showed assisting behavior.     

Cleaner fish, Labroides dimidiatus, diet preferences for different types of mucus and parasitic gnathiid isopods

Cleaner fish, Labroides dimidiatus, prefer the mucus of the parrotfish, Chlorurus sordidus, to parasitic gnathiid isopods, the main items in their diet, indicating a major conflict between clients and cleaners over what the latter should eat during interactions. We tested whether the conflict varied with client species (and the quality of its mucus) and with the presence of blood in the gnathiids. First, we offered cleaners the choice between mucus of the parrotfish and that of the snapper, Lutjanus fulviflamma. When offered equal amounts of mucus on Plexiglas plates, cleaners readily developed a significant preference for the parrotfish mucus. Reducing the amount of parrotfish mucus by 75% made the preference disappear. In a second test, we offered the cleaners gnathiids that were or were not engorged with client fish blood. Cleaners showed no significant preference for either food item. Our results suggest that the degree of conflict between cleaners and clients may vary between species, depending on whether the latter have a preferred mucus. In contrast, the cleaners' lack of preference for engorged gnathiids benefits clients because it means that cleaners do not hesitate to eat unengorged gnathiids before the gnathiids harm the fish by removing blood or by transmitting blood parasites.     

Directional orientation of pomacentrid larvae to ambient reef sound

The mechanisms by which reef fish larvae locate settlement habitat at the end of their pelagic phase are unclear. We used an in situ binary choice chamber and an artificial source of reef sound to determine whether pomacentrid larvae can use ambient sound to locate reefs. Larvae were caught in light traps and then placed in a submerged binary choice chamber with an artificial source of reef sound ~80 m from one end of the chamber. At night, larvae moved towards the sound source; during the day, larvae showed no preference. These results suggest that pomacentrid larvae can detect reef sound and are capable of directional hearing. While other studies have shown that reef fish larvae respond to reef sound, and that the adults of some species can localize underwater sound sources, the localization of underwater sound by fish larvae has not been demonstrated previously.Communicated by Ecological Editor P.F. Sale     

PRIMARY PRODUCTION REQUIRED TO SUPPORT BOTTLENOSE DOLPHINS IN A SALT MARSH ESTUARINE CREEK SYSTEM

We developed a model to estimate the proportion of annual primary production required to support bottlenose dolphins within the 32-km² North Inlet salt marsh creek system in South Carolina, U. S. A. The estimated annual prey consumption by dolphins was compared to the total annual production of prey available to dolphins, as determined from estimates of annual primary production, trophic transfer efficiencies, and the mean trophic level of prey. A best estimate range of 3.2%-6.8% of the total annual primary production of the North Inlet system was required to support an average population of only six dolphins (maximum range of 0.4%–7.0%). Dolphins were estimated to consume 11.1–14.2 metric tons of fish (wet weight) each year in North Inlet. The proportion of North Inlet primary production required to support dolphins increased dramatically during the winter months, when primary production declined but dolphin numbers remained similar. This period was marked by a decline in the abundance of available prey species and by a shift in the creek utilization patterns of dolphins. Despite the numerical scarcity of dolphins in the system, they appear to have a significant ecological impact and may be important predators of overwintering prey species.     

The Bacterial Flora of some Queensland Fish and its Ability to cause Spoilage

The bacterial flora were determined qualitatively and quantitatively on samples taken at various stages of handling several species of fish of commercial importance in Queensland. There was an overall increase in the number of bacteria during handling and processing; both the composition and quantity of the bacterial flora of individual samples taken at each stage of handling varied widely. Members of the genus Micrococcus formed the major proportion of the flora of freshly caught fish. Pseudomonas and Moraxella spp. were predominant amongst the bacterial flora able to grow at 2° and constituted the bulk of the population in samples with high bacterial counts. This psychrophilic population was markedly reduced at the filleting stage. A medium prepared by the action of trypsin on a fish muscle homogenate was used to test bacterial isolates for their ability to produce odours. Forty-three per cent of the pseudomonad isolates produced sulphydryl odours at 5°. Only small proportions of the other groups produced detectable odours. Members of the genus Pseudomonas were considered the most important fish spoilage bacteria under the conditions found in Queensland.     

Production of donor-derived offspring by allogeneic transplantation of Spermatogonia in the yellowtail (Seriola quinqueradiata)

Although the yellowtail (Seriola quinqueradiata) is the fish most commonly farmed in Japan, breeding of this species has not yet started. This is primarily due to the lack of sufficiently sophisticated methods for manipulating gametogenesis, which makes it difficult to collect gametes from specific dams and sires. If it were possible to produce large numbers of surrogate fish by transplanting germ cells isolated from donor individuals harboring desirable genetic traits, then the probability of acquiring gametes carrying the donor-derived haplotype would increase, and breeding programs involving this species might increase as a result. As a first step, we established a method for the allogeneic transplantation of yellowtail spermatogonia and the production of donor-derived offspring. Donor cells were collected from immature (10-month-old) yellowtail males with testes containing abundant type A spermatogonia, labeled with PKH26 fluorescent dye, and transferred into the peritoneal cavities of 8-day-old larvae. Fluorescence observation at 28 days post-transplantation revealed that PKH26-labeled cells were incorporated into recipients' gonads. To assess whether donor-derived spermatogonia could differentiate into functional gametes in the allogeneic recipient gonads, gametes collected from nine male and four female adult recipients were fertilized with wild-type eggs and milt. Analysis of microsatellite DNA markers confirmed that some of the first filial (F(1)) offspring were derived from donor fish, with the average contribution of donor-derived F(1) offspring being 66% and the maximum reaching 99%. These findings confirmed that our method was effective for transplanting yellowtail spermatogonia into allogeneic larvae to produce donor-derived offspring.