Description and phylogeny of Ceratomyxa anko sp. n. and Zschokkella lophii sp. n. from the Japanese anglerfish, Lophius litulon (Jordan)

Two new species of myxozoans from the Japanese anglerfish, Lophius litulon, are described using myxospore morphology and small subunit rDNA sequences. Ceratomyxa anko sp. n. is a parasite of the gall bladder and had a prevalence of 57%. Mature spores of C. anko sp. n. are arcuate to crescent shaped with valves tapering to rounded tips. A prominent sutural line runs centrally between the round adjacent polar capsules containing the polar filament coiled two to three times. Spore measurements: length 10.8 (9.7-11.9) microm, width 41.9 (36.9-47.2) microm, polar capsule diameter 4.6 (4.1-5.3) microm. Ceratomyxa anko sp. n. can be distinguished from other Ceratomyxa spp. due to its spore dimensions and shape. Zschokkella lophii sp. n. is a parasite of the urinary bladder and had a prevalence of 70%. Mature spores are ellipsoidal to semicircular with bluntly pointed ends. The sutural line is curved or sinuous and the valves have no discernable surface ornamentation. Two almost spherical polar capsules are located separately in the ends of the spore, opening in almost opposite directions and contain the polar filament with five coils. Spore measurements: length 20.1 (16.8-24.0) microm, width 14.9 (12.7-16.8) microm, polar capsule diameter 5.1 (3.6-5.8) microm. Zschokkella lophii sp. n. can be distinguished from other Zschokkella spp. due to the terminal opening of the polar capsules within the spores and the site of infection within the host fish. In the phylogenetic analyses, C. anko sp. n. grouped with other members of the same genus forming a monophyly. Zschokkella lophii sp. n. forms a discrete clade with another Zschokkella sp. that infects the urinary bladder of marine fish. This grouping forms a sister clade to one containing members of the genus Parvicapsula, all of which are parasites of the urinary system in marine fish.     

黄海和日本海黄鮟鱇的形态和同工酶差异

对中国黄海及日本新泻县粟岛近海的黄鮟鱇形态进行了比较研究,并采用水平淀粉凝胶电泳技术分别分析了黄海和日本海黄鮟鱇的遗传结构及其遗传多样性。结果表明,黄海和日本海黄鮟鱇群体计数性状中除第2背鳍鳍条数平均值表现出一定的差异,其余性状没有明显差异;二者在体长/臀鳍基长、头长/眼径指标未表现出显著差异,其余可量性状比上表现出了显著差异。同工酶分析表明,中国黄海黄鮟鱇群体共记录了8个基因位点,其中,LDH*、AAT*、GPI*和G3PDH*共4个基因位点呈多态,其多态座位比例为0.5,平均观测杂合度和预期杂合度分别为0.027和0.026,平均有效等位基因数为1.028,遗传偏离指数均大于零;而检测的日本海群体的6个基因位点中,没有出现多态位点。黄海和日本海黄群体间的遗传距离为0.00046,二者的遗传多样性水平较低,群体间没有明显的遗传分化。     

东海北部和黄海南部黄鮟鱇的数量分布及其群体结构特征

根据2008年5月（春）、8月（夏）、11月（秋）和2009年2月（冬）在26°00′~35°00′N、121°00′~127°00′E以西海域的底拖网调查资料,研究了东海北部、黄海南部黄鮟鱇Lophius litulon的数量分布、群体结构特征及其分布海域的环境特征。结果表明：东海北部、黄海南部黄鮟鱇主要分布在大沙渔场、江外渔场、舟外渔场和连青石渔场中南部;全年平均渔获率为0.143 kg/h,数量分布的高峰期出现在夏季,平均渔获率为0.298 kg/h,其次是冬季,为0.143 kg/h,春季最低,只有0.032 kg/h;渔获物体长为27~650mm,平均为268 mm,体重为0.6~6 715 g,平均为806 g,冬季渔获个体最大（292 mm,951 g）,夏季最小;4—5月为黄鮟鱇的集中产卵时间;黄鮟鱇分布海域的底层水温为6.43~20.01℃,平均为13.02℃;底层盐度为30.37~35.03,平均为32.90;水深分布为17.0~107.2 m,平均为64.4 m,密集分布区的水深为40~80 m。     

大连海域黄鮟鱇的生长特征与资源合理利用

[目的]制定大连海域黄鮟鱇开捕规格和总允许捕捞量.[方法]通过分析黄鮟鱇的体长—体重关系式和体长生长方程、体重生长方程、瞬时死亡率,计算体重生长的拐点年龄和临界年龄,估算大连海域黄鮟鱇的资源量.[结果]体长生长方程为Lt=576.4×[1-e-0.28(+0.44)],体重生长方程为Wt=5 344.3×[1-e-028(t+0.44]30052,黄鮟鱇体重生长的拐点年龄为4.2龄,临界年龄为4.7龄,大连海域黄鮟鱇的资源生物量为8 216.7 t.[结论]黄鮟鱇开捕体长419.2 ～ 439.7 mm,开捕体重2052.2～2 369.5 g,总允许捕捞量1 182t.     

黄海海域5种底栖型海水鱼类组织脂肪酸组成特征分析

本研究测定和评估了青岛地区5种底栖型海水鱼[(黄鮟鱇(Lophiuslitulon)、鲬(Platycephalusindicus)、长绵鳚(Zoarcesviviparu)、角木叶鲽(Pleuronichthyscornutus)和带纹条鳎(Zebriaszebrinus)的形体指标、肌肉和肝脏的粗成分,以及肌肉、肝脏、脑、眼、皮肤、肠道等组织的脂肪酸组成,以全面评估底栖型代表鱼类的脂肪和脂肪酸组成特征。实验鱼每种鱼9尾,3尾一组混样作为一个重复。结果显示,在5种鱼中,肌肉脂肪含量整体偏低,黄鮟鱇和带纹条鳎肌肉脂肪含量尤其低(0.3%～0.4%),但黄鮟鱇、鲬和角木叶鲽具有较高的肝脏脂肪含量(19%～29%),而带纹条鳎和长绵鳚肝脏脂肪含量偏低(4%～5%)。脂肪酸组成方面,黄鮟鱇肌肉中n-3系列长链多不饱和脂肪酸(long chain-polyunsaturated fatty acid, LC-PUFA)含量显著高于其他鱼,尤其以DHA最为明显。黄鮟鱇背肌中还具有最高含量的18:1n-9。长绵鳚背肌脂肪酸组成最明显的特征是较低的16:0含量和较高的20:4n-6及EPA含量。肝脏...     

Spraguea (Microsporida: Spraguidae) infections in the nervous system of the Japanese anglerfish, Lophius litulon (Jordan), with comments on transmission routes and host pathology

Anglerfish from the genus Lophius are a globally important commercial fishery. The microsporidian Spraguea infects the nervous system of these fish resulting in the formation of large, visible parasitic xenomas. Lophius litulon from Japan were investigated to evaluate the intensity and distribution of Spraguea xenomas throughout the nervous system and to assess pathogenicity to the host and possible transmission routes of the parasite. Spraguea infections in L. litulon had a high prevalence; all fish over 403 mm in standard length being infected, with larger fish usually more heavily infected than smaller fish. Seventy percent of all fish examined had some gross visible sign of infection. The initial site of development is the supramedullary cells on the dorsal surface of the medulla oblongata, where all infected fish have parasitic xenomas. As the disease progresses, a number of secondary sites typically become infected such as the spinal, trigeminal and vagus nerves. Fish with infection in the vagus nerve bundles often have simultaneous sites of infection, in particular the spinal nerves and along the ventral nerve towards the urinary bladder. Advanced vagus nerve infections sometimes form xenomas adjacent to kidney tissue. Spraguea DNA was amplified from the contents of the urinary bladders of two fish, suggesting that microsporidian spores may be excreted in the urine. We conclude that supramedullary cells on the hindbrain are the primary site of infection, which is probably initiated at the cutaneous mucous glands where supramedullary cells are known to extend their peripheral axons. The prevalence of Spraguea infections in L. litulon was very high, and infections often extremely heavy; however, no associated pathogenicity was observed, and heavily infected fish were otherwise normal.     

黄海南部和东海中北部黄鮟鱇数量分布及其与环境的关系

根据2004年4、6、9月和12月在黄海南部和东海中北部(27°00′~34°00′N、122°00′~127°00′E)进行的渔业资源大面定点底拖网调查资料,以相对资源密度指数作为指标值,分析了黄鮟鱇的时空分布特征。并利用GAM模型,分析了黄鮟鱇数量分布与经纬度、水深、底温和底盐等环境因子的关系。结果表明:黄鮟鱇主要分布在黄海南部和东海北部海区,4个季节的分布范围有明显不同,以春季为最大,冬季最小;黄鮟鱇适宜底温、底盐和水深范围分别为11~14℃、33.5~34.5和40~90 m;根据黄鮟鱇分布的底温范围,推断黄鮟鱇为冷温性鱼种。     

东海北部、黄海南部黄鮟鱇的年龄和生长

利用黄鮟鱇Lophius litulon耳石对2007年3月~2009年5月取自东海北部、黄海南部黄鮟鱇的年龄和生长特征进行了分析。结果显示,黄鱼安鱼康群体由1~5龄组成,以1~2龄鱼为主,捕捞群体呈低龄化;生长特点属均匀生长型,体重与体长关系为W=1.55897×10-5L3.10865,体长与耳石半径关系为L=244.11R-210.6,体长生长方程为Lt=749.9[1-e-0.349(t+0.256)],体重生长方程为Wt=13496.4[1-e-0.349(t+0.256)]3.10865,极限年龄Tmax为8.337龄,生长拐点年龄ti为2.994龄,此时对应的体长和体重分别为508.8mm和4038.7g。为保护黄鮟鱇资源,应限捕体长在500mm以下的个体。     

Verification of annual increment formation in the white anglerfish, Lophius piscatorius using the illicia and sagitta otoliths

Marginal and edge state analysis was carried out on sagitta otoliths and illicia of white anglerfish taken from ICES Sub-area VI and Division IVa between April 1999 and September 2000. This demonstrated that an annulus comprised a multi-ring opaque zone and a wide translucent zone. Narrow translucent zones within the wide opaque zones were found to be significantly narrower than the translucent zones separating them, suggesting that these were false rings. Opaque material was predominantly deposited during the summer months (July–September) and translucent material during the winter (December–February). Precision of increment readings was tested from repeated increment counts of the calcified structures. This indicated that the most consistent age readings came from sagitta otoliths sectioned through the sagittal plane.