东白令海三种经济鲽类捕捞群体结构与生长特性比较

对东白令海水域双线鲽(Lepidopsetta bilineata)、太平洋拟庸鲽(Hippoglosso-ides elassodon)和阿拉斯加鲽(Pleuronectes quadrituberculata)等三种经济鲽类的捕捞群体结构和生长特性进行比较。得出结论是:(1)捕捞群体结构复杂;(2)渐近体长和渐近体重较大、寿命长、K值小;(3)雌鱼比雄鱼个体大、生长快、寿命长;(4)三种鲽类的捕捞群体结构和生长特性有明显差异。     

Comparative Analysis of Mitochondrial Control Region Sequence from Three Flatfish Species （Pleuronectidae）

The 5‘-end of the mitochondrial control region sequences of three flatfishes (Pleuronectiformes: Pleuronectidae) were amplified and sequenced. These sequences were compared with those of other three Pleuronectids species retrieved from GenBank. A phylogenetic tree was constructed based on the partial control region sequences. The results of phylogenetic analysis are consistent with those of conventional systematics. Compared to previous studies, the structure of the 5‘-end of mitochondrial control region was analyzed. The terminal associated sequence motif and its complementary motif were identified at the 5‘-end of the sequences. A conserved sequence block, named as CM5‘ d, was identified in the 5‘-end of control region sequences in all Pleuronectids. Another central conserved sequence block, named as CSB-F, was detected in the central conserved blocks.     

Distribution and transport patterns of northern rock sole, Lepidopsetta polyxystra, larvae in the southeastern Bering Sea

We report the size, abundance, and distribution (horizontal, vertical) of northern rock sole, Lepidopsetta polyxystra, larvae collected from ichthyoplankton surveys on the southeastern Bering Sea shelf near Unimak Island, in Unimak Pass, and in the Gulf of Alaska south of Unimak Island. The greatest abundances of larvae occurred within Unimak Pass and in the Bering Sea northeast of Unimak Island. Larvae were smaller and more abundant in 2002 than in 2003. Larval abundance and size varied with depth. Highest abundances were at depths of 10-30 m during the day, and larger fish appeared to migrate from below 20 m to 0-10 m at night. There was evidence of multiple spawning locales and larval dispersal pathways that were depth- and area-specific. Northern rock sole larvae spawned west of Unimak Pass along the Aleutian Islands may be transported northward by the Bering Slope Current. Larvae spawned in the Gulf of Alaska and advected through Unimak Pass are differentially dispersed, primarily to the middle and outer shelves along the 100 m and 200 m isobaths, or along the Alaska Peninsula. Larvae spawned along the Alaska Peninsula east of Unimak Island appear to have the greatest chance of being transported to nursery areas in the coastal domain. Dispersal of near-surface northern rock sole larvae in any of these locations is likely influenced by wind-driven advection, but below-surface (>10 m) northern rock sole larval transport is probably more affected by factors that modulate geostrophic flow rather than wind-driven surface currents.     

Molecular phylogeny of familiar flatfish species(Pleuronectidae) in the northwestern Pacific Ocean based on mitochondrial cytochrome oxidase I gene

A molecular phylogenetic analysis was undertaken to evaluate the present systematic status of commercially familiar Pleuronectidae fishes in the northwestern Pacific Ocean. We sequenced a 529 bp fragment of the mitochondrial DNA （mtDNA） COl gene from 34 individuals of these familiar flatfishes from 11 species of nine genera collected in China and Japan. Genetic relationships among haplotypes of specimens from 11 species for COI gene data were reconstructed using the neighbour-joining method and the maximum parsimony （MP） method. The resulting molecular phylogeny of the 11 species, with a few exceptions, supported the existing taxonomy which was based largely on the morphological characteristics. The most noteworthy findings were that the genus Pleuronichthys diverged before deriving of the common ancestor for the other species; the stone flounder, Kareius biocoloratus, should belong to the genus Platichthys with the latin name Platichthys biocoloratus and the genus Verasper was not the extraordinary differ- entiation from the other species in family Pleuronectidae. The resultant phylogenetic trees were also consistent with multiple origins of direct development within family Pleuronectidae. New proof not only for further illuminating the multiple origins of Pleuronectidae but also for confirmation of the evolutionary relationships among groups in the family will be supported.     

Topographic influence on the winter Mid‐Tasman convergence (note)

Evidence from aerial infrared temperature measurements of the temperature front associated with the winter Mid‐Tasman Convergence Is presented. The position of this feature over the Norfolk Ridge suggests topographic influences on its formation.