Xenobalanus Globicipitis Research Articles (Page 1)

A twenty-five year old dataset of parasites in long-beaked and short-beaked common dolphins (Delphinus spp.), using fisheries as an opportunistic platform of access, registered seven species of helminths and one epizoite, being a unique dataset for the Southeast Pacific. Sampling was conducted in 1985-2000 at six fishing ports in Peru and Ecuador where cetaceans were landed from interactions with small-scale fisheries. From a total of 473 common dolphins examined, we identified helminths including three species of Trematoda: Nasitrema globicephalae, Pholeter gastrophilus, and Braunina cordiformis; three species of Nematoda, including Anisakis spp., Crassicauda spp., and Halocercus sp.; and two cestodes, Tetrabothrius forsteri and Clistobothrium delphini. No acanthocephalans were observed. No statistically significant sexual and ontogenetic variation in helminth prevalence was detected, after which samples were pooled. The highest prevalences in the long-beaked common dolphin (n = 440) were observed for N. globicephalae (87.9%, 29 infested/33 sampled) in cranial sinuses, Crassicauda sp1. (80%, 4/5) in mammary glands, followed by Cl. delphini (28.6%, 2/7) in the blubber, and P. gastrophilus (23%, 26/113) in the pyloric stomach. Although comparative testing was unfeasible due to minimal samples of short-beaked common dolphin (n = 33), several of the same helminth species were found; but not N. globicephalae nor B. cordiformis. No cyamids were encountered while pseudo-stalked barnacles Xenobalanus globicipitis were common. Although no new (global) helminth host records were revealed for common dolphins, this study presents a first checklist of parasites separately for the Southeast Pacific long-beaked and short-beaked common dolphins. Future work should include exhaustive laboratory-based necropsies, enhanced sampling of the short-beaked form, review data from recent parasite collections, focus on intermediate hosts and parasitic pathology, including potential human health impact from consumption of small cetaceans.

The Canary Islands are considered a hot spot for marine species biodiversity. Each stranded cetacean has provided important scientific, biological and pathological information. The morphological identification of parasites in these stranded cetaceans is the main aim of the present article. An investigation to identify parasites was carried out in 233 stranded animals (2018-2022), which were submitted for necropsy. Adult and sub-adult/juvenile animals were the most parasitized age categories, and eighteen parasite species were morphologically identified, including nematodes (Crassicauda grampicola, Crassicauda anthonyi, Halocercus delphini, Anisakis simplex, Stenurus globicephalae, Stenurus ovatus), trematodes (Nasitrema delphini, Oschmarinella rochebruni, Brachycladium atlanticum, Pholeter gastrophilus), cestodes (Clistobothrium delphini, Clistobothrium grimaldii), acanthocephalans (Bolbosoma vasculosum, Bolbosoma capitatum), protists (Toxoplasma gondii) and crustaceans (Conchoderma auritum, Xenobalanus globicipitis, Pennella balaenoptera), as well as nine genera: Crassicauda sp., Halocercus sp., Anisakis sp., Stenurus sp., Nasitrema sp., Oschmarinella sp., Dyphyllobothrium sp., Cyamus sp., Conchoderma sp., and Sarcocystis sp. These could not be identified at the species level. Differences in the host specificity of some parasites were observed, varying in prevalence. The accurate morphological identification of the parasites affecting these marine mammals is essential to understanding disease epidemiology, assessing cetacean populations' health status, and developing effective conservation and management strategies.

The presence of the offshore bottlenose dolphin (Tursiops truncatus) is poorly understood for most of the southeast Pacific Ocean. Its wide distribution, low density, and lack of understanding of its ecology make the species unpredictable to observe and difficult to study compared to the coastal ecotype. We assessed the occurrence of offshore bottlenose dolphins off the central coast of Ecuador (01°36’ S, 80°58’ W) using information taken from 2001 to 2022. Data were collected by two research groups based 80 km apart, one in Puerto López (north) and the other in Salinas (south). A total of 48 dolphin groups were documented, 22 at Puerto López and 26 at Salinas. In Puerto López, 163 dolphins were individually identified, of which 70 intra-annual sightings and 102 inter-annual sightings were found. Inter-annual resightings at Puerto López corresponded to 55 individuals (33.7%) recorded between two and 17 years (mean = 5.82 years, SD = 5.1). In Salinas, 58 dolphins were identified, without intra-annual resightings and only two inter-annual sightings. Only one individual was recorded in both areas. Two site fidelity indexes were calculated, Occurrence (Oi) and Permanence (Pi), resulting in 11 and 13.7 times higher respectively, in Puerto López. The abundance at Puerto López, 163 animals (95% CI, 120 - 203) in 2021-2022, was estimated with a closed population model. The prevalence of scars associated with previous encounters with fishing gear was 43.6%, commensal barnacle (Xenobalanus globicipitis) infestation 42.3%, predation 3.6%, and dermal nodules 0.61%. Our findings suggest both site fidelity and some degree of population structure, but additional monitoring and genetic studies are needed to clarify these aspects. Nevertheless, this study provides information on key aspects necessary for developing conservation strategies for offshore bottlenose dolphins.

This paper describes the interactions of the franciscana (Pontoporia blainvillei) with fisheries in the north of Rio de Janeiro State (210 18’S-220 25’S) and presents new information on its biology. A total of 181 dolphins were caught in gillnet fisheries in northern Rio de Janeiro from 1986-1999. The annual catch per unit effort (CPUE) values varied from 0.2-1.8 dolphins per gillnet fishing effort. Incidental captures were recorded throughout the year, usually less than 10 n.miles from shore, in depths less than 30m and in surface-set gillnets. There was no difference in the proportion of sexes (1 male:1.1 females). Males ranged from 66-130.0cm and 0-5 years and females from 74-147.5cm and 0-9 years. The predicted asymptotic length (using the Gompertz model) was 121.9cm for males and 145.6cm for females. Calving occurs throughout the year, with no seasonal pattern. Females attain sexual maturity at 3 years and 130.0cm in length and males at 2 years and 115.0cm. Individuals up to the age of three years represented 74% of the dolphins captured. Franciscana preferentially feed on the teleosts Stellifer sp., Anchoa filifera, Pellona harroweri and Isopisthus parvipinnis, measuring up to 10cm of length, and on the cephalopods Loligo sanpaulensis and L. plei. No internal parasites were observed. The barnacle Xenobalanus globicipitis was recorded on only one individual. Sightings were recorded in all seasons and 90% of them were obtained up to 5 n.miles from shore, in waters up to 15m deep. Around 70% of groups sighted consisted of up to five dolphins. Estimates of the population size and continuous gillnet fleet monitoring are required to conserve franciscana in the northern limit of its distribution range. The differences in the somatic, reproductive and genetic patterns of franciscana represent important aspects that may be used as evidence to best define their stocks. These variations may reflect the reduction of gene flow between populations, the allocation of resources between growth and reproduction and/or the influence of environmental features, such as water temperature and food availability.

Abstract Barnacles can reveal much about the physiology, health, and spatial ecology of their cetacean hosts. Here, we examine how temperature and hydrodynamic factors impact presence of Xenobalanus globicipitis, a pseudo‐stalked barnacle that attaches exclusively to cetaceans. We hypothesized that temperature is a key environmental factor (i.e., water temperature) and physiological factor, in that X. globicipitis prefers the warmest skin temperature for attachment, possibly as a mechanism for survival in colder waters. First, we demonstrate a global relationship between spatial ecology of host species and presence of X. globicipitis. Notably, X. globicipitis is absent in the four species occupying waters with the lowest sea surface temperature (SST) year‐round, but present in migratory species that likely acquire the barnacle in waters with higher SST. Second, barnacle attachment location on common bottlenose dolphin (Tursiops truncatus) dorsal fins corresponds with fin temperature and hydrodynamics. Although body temperature may influence attachment location on the body of the animal, hydrodynamic forces, as previously proposed, determine how well barnacles can remain attached during the adult stage. X. globicipitis prevalence likely provides important bioindicator, ecological, and physiological information about its host. As parasitic infestation has some cost, these results have implications for cetacean health in warming seas.

In the eastern North Pacific Ocean, common minke whales (Balaenoptera acutorostrata) are widespread but encountered relatively infrequently. It is generally believed that they make annual migrations between higher latitudes in the summer and lower latitudes in the winter; however, in some temperate coastal regions where common minke whales have been sighted year-round they have been referred to as resident. To determine movement patterns of common minke whales found in coastal waters of British Columbia and Washington we examined photo-identification data that were collected opportunistically from 2005–12. These data were from four non-overlapping areas between 48°N and 53°N. Despite year-round search efforts, common minke whales were only encountered between April and October. Most of the 44 unique individuals identified in 405 encounters displayed fidelity to areas both within and among years. Five of these whales made relatively large-scale intra-annual movements between areas on six occasions. They were documented to move up to 424km in a northerly direction in spring and up to 398km in a southerly direction in autumn. The seasonal patterns of these movements provide new insights into the foraging ranges and migrations of the individuals. Ecological markers provide evidence that the common minke whales photographed undertake annual long distance migrations. Scars believed to be from cookiecutter shark (Isistius brasiliensis) bites were observed on 43 individuals and the majority of whales documented with good quality images each year had acquired new scars since the previous year. Furthermore, the commensal barnacle Xenobalanus globicipitis was observed on three individuals. Since these sharks and barnacles are from relatively warm waters, it can be inferred that they interacted with the common minke whales at lower latitudes. These findings may have important implications for the definition and management of common minke whale stocks and/or populations in the eastern North Pacific.

Antarctic minke whales, Balaenoptera bonaerensis, breed in tropical and temperate waters of the Southern Hemisphere in winter and feed in Antarctic grounds in the austral summer. These seasonal migrations could be less defined than those of other whale species, but the evidence is scanty. We quantitatively describe the epibiotic fauna of Antarctic minke whales and explore its potential to trace migrations. Seven species were found on 125 out of 333 examined Antarctic minke whales captured during the last Antarctic NEWREP-A expedition in the Southern Ocean: the amphipod Balaenocyamus balaenopterae (prevalence = 22.2%), the copepod Pennella balaenoptera (0.6%); three coronulid, obligate barnacles, Xenobalanus globicipitis (11.1%), Coronula reginae (8.7%), C. diadema (0.9%); and two lepadid, facultative barnacles, Conchoderma auritum (9.0%) and C. virgatum (0.3%). Species with prevalence > 8% exhibited a modest increase in their probability of occurrence with whale body length. Data indicated positive associations between coronulid barnacles and no apparent recruitment in Antarctic waters. All specimens of X. globicipitis were dead, showing progressive degradation throughout the sampling period, and a geographic analysis indicated a marked drop of occurrence where the minimum sea surface temperature is < 12 °C. Thus, field detection -with non-lethal methodologies, such as drones- of coronulid barnacles, especially X. globicipitis, on whales in the Southern Ocean could evince seasonal migration. Future investigations on geographical distribution, growth rate, and degradation (for X. globicipitis) could also assist in timing whales’ migration.

The social structure of estuarine-resident bottlenose dolphins is complex and varied. Residing in habitats often utilized for resource exploitation, dolphins are at risk due to anthropogenic pressures while still federally protected. Effective conservation is predicated upon accurate abundance estimates. In North Carolina, two estuarine-resident stocks (demographically independent groups) of common bottlenose dolphin have been designated using spatiotemporal criteria. Both stocks are subjected to bycatch in fishing gear. The southern North Carolina estuarine stock was estimated at <200 individuals from surveys in 2006, which is outdated per US guidelines. Thus, we conducted a new capture-mark-recapture survey in 2018, identifying 547 distinct individuals, about three times higher than the prior abundance estimate. We compared those individuals to our long-term photo-identification catalog (1995–2018, n = 2,423 individuals), matching 228 individuals. Of those 228, 65 were also included in the 2013 abundance estimate for the northern North Carolina estuarine stock. Using sighting histories for all individuals in the long-term catalog, we conducted a social network analysis, which is independent of a priori stock assignments. The three primary clusters identified were inconsistent with current stock designations and not defined by spatiotemporal distribution. All three clusters had sighting histories in the estuary and on the coast, however, that with the highest within-cluster associations appeared to use estuarine waters more often. The within-cluster association strength was low for one cluster, possibly due to only part of that cluster inhabiting the southern North Carolina estuarine system. Between-cluster differences occurred in infestation rates by the pseudostalked barnacle, Xenobalanus globicipitis, but that did not predict clusters. We suggest the need to re-evaluate the stock structure of estuarine-resident common bottlenose dolphins in North Carolina and currently have insufficient information to assign an abundance estimate to a currently designated stock.

Emergence of the epibiotic barnacle Xenobalanus globicipitis in Guiana dolphins after a morbillivirus outbreak in Sepetiba Bay, Brazil

Duration of pseudo-stalked barnacles (Xenobalanus globicipitis) on a New Zealand Pelagic ecotype orca (Orcinus orca), with comments on cookie cutter shark bite marks (Isistius sp.); can they be used as biological tags?

Xenobalanus globicipitis is a commensal barnacle located on cetacean fin edges. The commensal-host interaction between Xenobalanus globicipitis and the bottlenose dolphin (Tursiops truncatus) has been poorly studied in Mexico. The main objective was to estimate the relative barnacle prevalence and abundance in bottlenose dolphins in three areas and seasons of the Gulf of Mexico. Tamiahua zone showed the higher prevalence (42.4%) and relative abundance (0.60 barnacles/individual/hr-1)compared to Tuxpan and Nautla zones. Whereas, in dry season there were higher prevalence (55.6%) and relative abundance (0.53 barnacles/individual/hr-1)than rainy and winter storm seasons. Therefore, zones and seasons of the Gulf of Mexico influence the barnacle-dolphin interactions.

How whale and dolphin barnacles attach to their hosts and the paradox of remarkably versatile attachment structures in cypris larvae

Abstract We analyzed patterns of aggregation and spatial distribution of the epizoic barnacle Xenobalanus globicipitis on the flukes of Mediterranean striped dolphins, Stenella coeruleoalba, assessing its potential use as an indicator of the host's hydrodynamics based on data from 55 dolphins. Barnacles occurred along the trailing edge with the cirri oriented towards the oncoming flow. Nearest neighbor analyses suggested that new recruits actively seek placement next to already settled barnacles, forming aggregations possibly to facilitate copulation. The probability of spanwise settlement strongly increased with fluke width (presumably enabling prolonged leading‐edge vorticity), and with chordwise length where pressure is predicted to be positive. Consequently, clustering tended to increase nonlinearly towards the fluke notch. Furthermore, it was three times more likely for barnacles to occur on the dorsal vs. ventral side of flukes, at an average abundance ca. 12 times higher. This difference could result from a host's asymmetric oscillation of the tail, which would alter leading‐edge vorticity, and/or an interaction between the wake produced by the dorsal fin and the flow associated with flukes. Both processes could primarily enhance cyprid contact and/or attachment on the dorsal side. This study offers a starting point for future comparison with other cetaceans.

Long-term population trend of the epibiont barnacle Xenobalanus globicipitis in the western Mediterranean: is there a role for viral outbreaks in its cetacean hosts?

The highly specialized coronulid barnacle Xenobalanus globicipitis attaches exclusively on cetaceans worldwide, but little is known about the factors that drive the microhabitat patterns on its hosts. We investigate this issue based on data on occurrence, abundance, distribution, orientation, and size of X. globicipitis collected from 242 striped dolphins (Stenella coeruleoalba) that were stranded along the Mediterranean coast of Spain. Barnacles exclusively infested the fins, particularly along the trailing edge. Occurrence, abundance, and density of X. globicipitis were significantly higher, and barnacles were significantly larger, on the caudal fin than on the flippers and dorsal fin. Barnacles were found more frequently and in greater numbers on the dorsal rather than ventral side of the caudal fin and on the central third of dorsal and ventral fluke surfaces. Nearly all examined individuals attached with their cirral fan oriented opposite to the fluke edge. We suggest that X. globicipitis may chemically recognize dolphins as a substratum, but fins, particularly the flukes, are passively selected because of creation of vortices that increase contact of cyprids with skin and early survival of these larvae at the corresponding sites. Cyprids could actively select the trailing edge and orient with the cirri facing the main direction of flow. Attachment on the dorsal side of the flukes is likely associated with asymmetrical oscillation of the caudal fin, and the main presence on the central segment of the flukes could be related to suitable water flow conditions generated by fluke performance for both settlement and nutrient filtration.

Coastal dolphins are regarded as indicators of changes in coastal marine ecosystem health that could impact humans utilizing the marine environment for food or recreation. Necropsy and histology examinations were performed on 35 Indian Ocean bottlenose dolphins (Tursiops aduncus) and five Indo-Pacific humpback dolphins (Sousa plumbea) incidentally caught in shark nets off the KwaZulu-Natal coast, South Africa, between 2010 and 2012. Parasitic lesions included pneumonia (85%), abdominal and thoracic serositis (75%), gastroenteritis (70%), hepatitis (62%), and endometritis (42%). Parasitic species identified were Halocercus sp. (lung), Crassicauda sp. (skeletal muscle) and Xenobalanus globicipitis (skin). Additional findings included bronchiolar epithelial mineralisation (83%), splenic filamentous tags (45%), non-suppurative meningoencephalitis (39%), and myocardial fibrosis (26%). No immunohistochemically positive reaction was present in lesions suggestive of dolphin morbillivirus, Toxoplasma gondii and Brucella spp. The first confirmed cases of lobomycosis and sarcocystosis in South African dolphins were documented. Most lesions were mild, and all animals were considered to be in good nutritional condition, based on blubber thickness and muscle mass. Apparent temporal changes in parasitic disease prevalence may indicate a change in the host/parasite interface. This study provided valuable baseline information on conditions affecting coastal dolphin populations in South Africa and, to our knowledge, constitutes the first reported systematic health assessment in incidentally caught dolphins in the Southern Hemisphere. Further research on temporal disease trends as well as disease pathophysiology and anthropogenic factors affecting these populations is needed.

Xenobalanus globicipitis, a unique type of small pseudo-stalked barnacle occurs on the appendages of cetaceans, including the common bottlenose dolphin Tursiops truncatus. In this study, we examined attachment structures of X. globicipitis and modifications to the skin of T. truncatus in areas of attachment compared to skin nearby an attachment site. Barnacles and their six calcareous footplates were measured for their length and width. There was a positive correlation of barnacle width and length to footplate width and length. The thickness of the stratum corneum increased significantly in areas of attachment compared to skin nearby a footplate. The mitotic stratum germinativum at the base of the dermal papillae did not change significantly in areas of attachment compared to skin nearby a footplate. The stratum germinativum lining the lateral walls of the dermal papillae was significantly thicker in areas of skin nearby a footplate compared to in areas of attachment. Skin of T. truncatus nearby a footplate, displayed dermal papillae extending from the dermis and pointing roughly perpendicular to the epidermal stratum corneum. At sites of X. globicipitis attachment, the dermal papillae were forced to extend laterally, parallel to the stratum corneum, and the dermal papillae length to width ratio at an attachment site was significantly higher than on skin near an attachment site. Our results show that attachment of X. globicipitis through production of footplates organized into calcareous rings, leads to a thickened stratum corneum of the epidermis, a thinner lateral mitotic stratum germinativum and displaced structures of the upper dermis. These resulting modifications to the epidermis and dermis of the host may add to securing barnacle attachment to its host.

Abstract The population structure of bottlenose dolphins, Tursiops truncatus, along the U.S. Atlantic coast has recently been redefined from one homogenous population into five coastal stocks. Local studies indicate even finer structure, primarily based on isolation of dolphins inhabiting estuaries. We identified population structuring of non‐estuarine coastal bottlenose dolphins during a study in New Jersey, the northern range along the Atlantic Coast. Using photo‐identification and distribution survey results, an analysis identified two major clusters of individuals significantly separated by five variables (distance from shoreline, group size, occurrence of the barnacle Xenobalanus globicipitis, avoidance behavior, and individual coloration). Sightings assigned to cluster 1 occurred in nearshore shallow waters (0–1.9 km, x̄= 3.5 m), and those assigned to cluster 2 occurred further offshore in deeper waters (1.9–6 km, x̄= 9.5 m). Only eight of 194 individuals (4%) were identified in both regions. Collectively, this suggests an occurrence of two stocks that are spatially, physically, and behaviorally distinguishable over a small distance. These results indicate that complexity in Tursiops population structure is not limited to latitudinal gradients or barriers created by estuarine habitats, but also by partitioning of habitat as a function of distance from shore and depth over small distances.

The present paper is the first annotated account listing all species of Cirripedia: Thoracica recorded from the Canary Islands (eastern Atlantic Ocean) together with notes on their distribution and ecology. Voucher specimens have been deposited as reference material in the collection of the Instituto Canario de Ciencias Marinas. Seventeen species are listed and seven of them are recorded for the first time for the Canaries:Lepas hilli, Conchoderma virgatum, Xenobalanus globicipitis, Chthamalus sp. (cf.C. proteus), Acasta cyathus, Balanus trigonusandPerforatus perforatus.

Parasites of cetaceans stranded on the Pacific coast of Costa Rica