Hayward C J, Perera K M, Rohde K
Department of Zoology, University of New England, Armidale, NSW, Australia.
Int J Parasitol. 1998 Feb;28(2):263-73. doi: 10.1016/s0020-7519(97)00186-0.
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.
对453条澳大利亚鲭（Scomber australasicus）进行了检查，这些鱼的体长在14.1至46.5厘米之间，于5年时间里从澳大利亚东南部的一个地点采集了12个样本。记录了10种体外寄生虫：6种单殖吸虫、3种桡足类动物和1种等足类动物。任何一条鱼体内寄生虫种类的最大数量达到5种，寄生虫总强度的最大值达到39。宿主大小是影响澳洲鲭体外寄生虫群落结构的一个重要决定因素：体长在20至25厘米之间的鱼，每条宿主的平均物种数在2.2时达到峰值，然后在更大的鱼中下降；每条鱼身上所有寄生虫的丰度同样在20 - 25厘米的鱼中达到峰值（平均为9.9）。单殖吸虫小伪库恩吸虫（Pseudokuhnia minor）在所有寄生虫中具有最高的患病率和丰度，感染了几乎80%体长小于25厘米的鱼。寄生虫总数的一半以上属于该物种，并且在其出现的鱼中，强度占主导地位的情况超过一半。当考虑近似体积时，体长小于20厘米的鱼中，群落以鲭库恩吸虫（Kuhnia scombercolias）为主；体长在20 - 34.9厘米的鱼中，以鲐库恩吸虫（Kuhnia scombri）为主；体长大于35厘米的鱼中，以小伪库恩吸虫为主。这三种单殖吸虫的强度彼此之间呈非常强的正相关，小伪库恩吸虫和南方格鲁伯吸虫（Grubea australis）的强度也是如此；只有一对物种的强度呈负相关（鲭库恩吸虫和等足类动物覆瓦状角头水虱（Ceratothoa imbricata））。嵌套子集分析表明，体外寄生虫群落是随机的。这以及低感染率和丰度，以及每条鱼的低物种丰富度，表明亚群落是隔离主义的。
