Effects of immunostimulants on ranched southern bluefin tuna Thunnus maccoyii: immune response, health and performance.

Ranched southern bluefin tuna Thunnus maccoyii were fed baitfishes supplemented with vitamins (predominantly E and C) or vitamins and immunostimulants, nucleotides and ß-glucans, over 12 weeks after transfer and monitored for enhancement in immune response, health and performance through their 19 week grow-out period. Fish from two different tows were sampled separately at three different sampling points: at transfer to grow-out pontoons, at 8 weeks post-transfer and at harvest, 19 weeks post-transfer. Lysozyme activity was enhanced during vitamin supplementation compared to control fish. Performance (i.e. survival, condition index and crude fat), health (i.e. blood plasma variables including pH, osmolality, cortisol, lactate and glucose) and alternative complement activity were not commonly improved through diet supplementation. There were some tow-specific improvements in performance through vitamin supplementation including survival, selected parasite prevalence and intensity, and alternative complement activity. Immunostimulant supplementation also showed a tow-specific improvement in plasma cortisol level. Tow-specific responses may suggest that life history, previous health condition and husbandry can affect the success of vitamin and immunostimulant enhancement of immune response, health and performance of ranched T. maccoyii.

Seasonal epizootics of sea lice, Caligus spp., on southern bluefin tuna, Thunnus maccoyii (Castelnau), in a long-term farming trial.

Within the typical 2-8 month (January to August inclusive) farming cycle for southern bluefin tuna, Thunnus maccoyii (Castelnau), in Spencer Gulf, South Australia, counts of a sea louse, Caligus chiastos Lin et Ho, 2003, were strongly statistically associated with both fish condition and severity of eye damage. During a trial examining the feasibility of maintaining T. maccoyii in farms for more than 1 year, including over the summer season when temperatures may exceed 24 degrees C, we collected additional epidemiological data on burdens of sea lice over a 17-month period (April 2005 to August 2006 inclusive), on a total of 200 T. maccoyii and 40 'control'T. maccoyii farmed and harvested within 2006. In the first farming season, an epizootic of C. chiastos was characterized by a significant increase in prevalence from 0% to 55% in the first 6 weeks after transfer to farms from the wild, which was followed by a significant decline to zero over the next 12 weeks. A single specimen of a second species of Caligus was also detected within this 4.5-month period. In the second farming season, we recorded a third species of sea louse, C. amblygenitalis Tripathi, 1961. In March 2006, a second epizootic peak occurred, this time with mixed infections of C. chiastos and C. amblygenitalis, with a combined prevalence of 100%. The prevalence of both sea lice species then declined significantly over the second winter period (June to August inclusive). On all but one date that sea lice were detected, sea lice counts were significantly associated with the severity of gross eye damage. Because both peaks in infection occurred in summer months (December to February inclusive), we conclude that infections of sea lice pose a risk to the farming of T. maccoyii under certain summer conditions within Spencer Gulf.

Diseases of tunas, Thunnus spp.

Much is known about those aspects of tuna health which can be studied in wild populations, e.g. helminth parasites. However, because aquaculture of these species is in its infancy, knowledge of microbial, nutritional and environmental diseases is limited. This review is an attempt to bring together the available information on those diseases of Thunnus spp. which cause significant morbidity, mortality or economic loss. In doing so it has become clear that much more research needs to be undertaken on the physiology of the species (southern, northern and Pacific bluefin tuna) currently used in aquaculture in order for the pathogenesis of some conditions to be properly understood. Attempts at hatchery culture of Pacific bluefin tuna has indicated that Thunnus spp. will be problematic to hatch and propagate.

First report of the invasive eel pest Pseudodactylogyrus bini in North America and in wild American eels.

We detected 2 species of monogenean gill worms, Pseudodactylogyrus bini (Kikuchi, 1929) Gusev, 1965 and P. anguillae (Yin & Sproston, 1948) Gusev, 1965 (Monopisthocotylea: Pseudodactylogyridae), on American eel Anguilla rostrata in 2 rivers in South Carolina, USA. One of these, P. anguillae, was reported 5 yr ago from Nova Scotia; as well as in South Carolina, we also discovered it in 2 localities in Chesapeake Bay. Differences in the morphologies of specimens of either species of worm from North America and northeastern Asia were negligible. Similarly, the level of variation in sequences in the ITS2 (internal transcribed spacers) region of ribosomal RNA was minor, and not consistent with geographical origin. These data indicate that these monogeneans invaded North America only recently, possibly in parallel with the nematode Anguillicola crassus (which is known to have been introduced with commercial imports of foreign eels). We map the current global occurrence of these monogeneans, and conclude that their dispersal from northeastern Asia was largely as a result of the eel trade, and has probably been secondarily augmented by longshore migration of infected eels, and possibly also by transport in ballast waters. With present technology, all eel stocks must still be collected from the wild; unless shipments are disinfected at quarantine, these and other eel pathogens (such as A. crassus) are likely to continue to colonise other regions of the world.

Oceanic barriers as indicated by scombrid fishes and their parasites.

Four genera of scombrid fishes (26 species) and their copepod (32 species) and monogenean ectoparasites (25 species) were used to test the hypothesis that the East Pacific Barrier is responsible for the most pronounced break in the circum-tropical warm water fauna of the continental shelves, and not the New World Barrier. Analysis at the species level showed that there is a primary centre of diversity in the West Pacific, and a secondary centre in the West Atlantic. The former, almost entirely, shares its species of the largely coastal Scomberomorus and Grammatorcynus and their parasites with seas located to the west. Only four parasites (all copepods) are shared by the East and West Pacific, and they are circum-tropical. In contrast, the West Pacific shares species of the more pelagic Scomber and their parasites with seas both to the east and west, although at the genus level, only two circum-tropical monogenean genera are shared by the E and W Pacific. We conclude that the East Pacific Barrier has been a 100% or almost 100% effective barrier to dispersal of species of Scomberomorus, Grammatorcynus and their parasites, whereas for species of Scomber and their parasites, the East Pacific has been a less effective barrier.

Scomberomorocotyle munroi n. g., n. sp. (Scomberomorocotylinae n. subf.), a thoracocotylid monogenean from Scomberomorous munroi (Scombridae) off Australia and Papua New Guinea.

Scomberomorocotyle munroi n. g., n. sp. is described from the gills of Scomberomorus munroi, a Spanish mackerel from the coasts of northern Australia and southern Papua New Guinea. The genus belongs to the suborder Gastrocotylinea because a pair of basal accessory sclerites is present in the clamps. However, the worm does not belong to any of the eight gastrocotylinean families as they are currently recognised. The worm appears to be a member of the Thoracocotylidae, in that the male copulatory organ has relatively weakly developed spines, and that the haptor is one-sided with two rows of clamps. However, the worm differs from all thoracocotylids in that the clamps lack the characteristic lateral rib-like thickenings. To accommodate the new genus and species, the diagnosis of the Thoracocotylidae Price is amended to include worms lacking ribs in their clamps, and a new subfamily, the Scomberomorocotylinae n. subfam., is erected; a key to the four subfamilies which we recognise as valid is provided.

Revision of the monogenean subfamily Thoracocotylinae price, 1936 (Polyopisthocotylea: Thoracocotylidae), with the description of a new species of the genus Pseudothoracocotyla Yamaguti, 1963.

Members of the subfamily Thoracocotylinae are gastrocotylid monogeneans of Spanish mackerels (scombrid fishes of the genus Scomberomorus) from warm to warm-temperate seas around the world. We revise the diagnosis of the subfamily and recognise two genera and three species as valid. The genus Paradawesia Bravo Hollis & Lamothe Argumedo, 1976 is synonymised with Thoracocotyle MacCallum, 1913, and Dawesia Unnithan, 1965 and Methoracocotyle Lebedev, 1984 are synonymised with Pseudothoracocotyla Yamaguti, 1963. Thoracocotyle crocea MacCallum, 1913 (syns T. paradoxica Meserve, 1938 and Paradawesia bychowskyi Bravo Hollis & Lamothe Argumedo, 1976) is recorded from two species of Scomberomorus in the eastern Pacific (California to Peru) and four in the western Atlantic (South Carolina to Brazil). Pseudothoracocotyla ovalis (Tripathi, 1956) Yamaguti, 1963 (new syns Dawesia indica Unnithan, 1965, D. incisa Lebedev, 1970, Methoracocotyle scomberomori (Young, 1968) Lebedev, 1984, M. gigantica (Rohde, 1976) Lebedev, 1984 and Thoracotyle indica (Unnithan, 1965) Murugesh, 1995) is recorded from the gills of seven species of Scomberomorus from the Indo-west Pacific (eastern South Africa north to the Persian Gulf, and east to Fiji). Pseudothoracocotyla whittingtoni n. sp. is described from an eighth Indo-west Pacific scomberomorid, S. munroi, in Australian waters.

Revision of the monogenean subfamily Priceinae Chauhan, 1953 (Polyopisthocotylea: Thoracocotylidae).

Members of the subfamily Priceinae are gastrocotylinean monogeneans of the gills of scombrid fishes of the genus Scomberomorus (and perhaps the genera Acanthocybium, Rastrelliger and Katsuwonus) from warm to warm-temperate seas of the world. We revise the diagnosis of the subfamily and regard the Mexicotylinae Lebedev, 1984 as a synonym. Two monotypic genera are accepted as valid. Pricea multae Chauhan, 1945 is recorded from seven species of Scomberomorus from the Indo-west Pacific, from off eastern South Africa north to the Persian Gulf and as far east as Fiji. New synonyms we recognise include P. minimae Chauhan, 1945 (described from India, reportedly on Katsuwonus pelamis), P. solandri Gupta & Chanana, 1977 (a single specimen was described from India, reportedly on Acanthocybium solandri) and P. microcotylae Chauhan, 1945 (also described from India, reportedly on Rastrelliger kanagurta). Mexicotyle mexicana (Meserve, 1938) Lebedev, 1984 is recorded on four species of Scomberomorus from the western Atlantic Ocean (United States to Brazil), two in the eastern Pacific (California to Peru) and one from the eastern Atlantic (Ghana).

Revision of the monogenean subfamily Neothoracocotylinae Lebedev, 1969 (Polyopisthocotylea: Thoracocotylidae).

Members of the subfamily Neothoracocotylinae are gastrocotylinean monogeneans on the gills of scombrid fishes of the genera Scomberomorus and Acanthocybium, and reportedly of a coryphaenid fish belonging to the genus Coryphaena. We revise the diagnosis of the subfamily and its two genera and accept only two species as valid. Neothoracocotyle acanthocybii (Meserve, 1938) Hargis, 1956 is known from Acanthocybium solandri throughout the Pacific Ocean and in the western Atlantic. N. coryphaenae (Yamaguti, 1938) Hargis, 1956, known only from a single specimen and described from Coryphaena hippurus in Japan, is synonymised with N. acanthocybii. The sole member of Scomberocotyle, S. scomberomori (Koratha, 1955) Hargis, 1956, infects five species of Scomberomorus in the eastern Pacific Ocean and the western and castern Atlantic. We record this worm from several new hosts and/or localities, including S. sierra and S. concolor in the eastern Pacific (Mexico to Colombia), S. maculatus and S. cavalla in the western Atlantic (USA to Brazil), and S. tritor in the eastern Atlantic (Sierra Leone to Nigeria).

Assemblages of ectoparasites of a pelagic fish, slimy mackerel (Scomber australasicus), from south-eastern Australia.

Four-hundred and fifty-three Scomber australasicus, ranging in length from 14.1 to 46.5 cm and taken in 12 samples over 5 years from a single locality in south-eastern Australia, were examined. Ten species of ectoparasites were recorded: six monogeneans, three copepods and one isopod. The maximum number of parasite species in any one fish reached five, and the maximum total parasite intensity reached 39. Host size is an important determinant of the structure of ectoparasite assemblages of slimy mackerel: the average number of species per host peaked at 2.2 in fishes between 20 and 25 cm in length, then declined in larger fish; the abundance of all parasites on each fish similarly peaked in fishes 20-25 cm (mean of 9.9). The monogenean Pseudokuhnia minor had the highest prevalence and abundance of all parasites, infecting almost 80% of fish < 25 cm long. Over half of the total number of parasites belonged to this species, and it was dominant in intensity in just over half of the fish in which it occurred. When approximate volume was considered, assemblages were dominated by Kuhnia scombercolias in fish < 20 cm, by Kuhnia scombri in fish 20-34.9 cm, and by P. minor in fish larger than 35 cm long. The intensities of these three monogeneans were very strongly and positively correlated with each other, as were the intensities of P. minor and Grubea australis; the intensities of only one pair of species were associated negatively (K. scombercolias and the isopod Ceratothoa imbricata). A nested subset analysis indicates that the ectoparasite assemblages are random. This and the low prevalences and abundances of infection, as well as low species richness per fish, indicate that infra-assemblages are isolationist.

Helminth ectoparasites of sillaginid fishes (Perciformes: Percoidei) have low species richness.

Just nineteen species of ectoparasitic helminths were found in a survey of over 1,500 individuals of 26 species of sillaginid fishes in the Indo-west Pacific. A twentieth worm is known only from the literature; a twenty-first, also known only from the literature, is considered a doubtful record. Fifteen of the twenty worms are branchial monogeneans, one is a monogenean of the pharyngeal plates, one is an ectoparasitic digenean living under the scales, and three are leeches of the mouth cavity and fins. The most common monogeneans were diplectanids (Diplectanum spp. and Monoplectanum spp.) and microcotylids (Polylabris spp.), each with five recently described or redescribed species. Of the remaining monogeneans, three were extremely rare, and two were uncommon. Pseudobivagina sp. and Polynemicola sp. (Microcotylidae) and Pseudempleurosoma sp. (Ancyrocephalidae) were represented by only a single worm each from three different hosts (Sillago robusta, S. sihama, and S. ingenuua, respectively). The gyrodactylid Gyrodactylus sp. is widespread and was recorded from four species of sillaginids (S. ciliata, S. japonica, S. schomburgkii and S. sihama). Encotyllabe chironemi Robinson (Capsalidae) is recorded for the first time from sillaginids, but only on S. aeolus. Two additional monogeneans are known from sillaginids only in the literature: Dactylogyrus sp. (Dactylogyridae) is known only from cultured S. sihama; the single specimen of Microcotyle sp. (Microcotylidae) recorded from Sillaginodes punctata is probably a contaminant, since the haptor was missing. The generalist trematode Transversotrema licinum Manter (Transversotrematidae) was found for the first time in samples of four species of sillaginids (Sillago analis, S. ingenuua, S. lutea and S. sihama). Three species of piscicolid leeches were encountered: Austrobdella translucens Badham was common on the fins of three large inshore sillaginids (S. ciliata, S. schomburgkii and S. analis); a single specimen of the generalist species Zeylanicobdella arugamensis De Silva was recovered from S. soringa; and specimens of Z. stellata (Moore) infected S. schomburgkii and S. analis. The diversity of host-specific worms in Sillaginidae is low compared with those of some other Indo-west Pacific fishes.

Investigation of bioequivalence and tolerability of intramuscular ceftriaxone injections by using 1% lidocaine, buffered lidocaine, and sterile water diluents.

The pharmacokinetics and tolerability of 1-g doses of ceftriaxone diluted in sterile water, 1% lidocaine, or buffered lidocaine were investigated. No difference in bioequivalence was noted between the three treatments. No difference in peak creatine kinase values was seen. By use of a quantitative pain scale, injection of ceftriaxone with the water diluent was significantly more painful than that with either of the other two diluents. No difference in injection pain was noted for lidocaine or buffered lidocaine.

The characterization of three monkey kidney cell lines.

Three monkey kidney cell lines, Vero, GL-V3 and MA-104 were subjected to karyological analysis to determine their chromosomal stability and to confirm their species of origin. Although the lines were shown to be relatively stable throughout all of the passage levels that were tested, the species of origin of one of them was found to be different from that claimed by the originators. This finding was supported by data from isoenzyme studies.