Nucleotide sequence variation of the mitochondrial COI gene in several eelpout species of the genus Zoarces (Zoarcidae, Pisces)

The mitochondrial COI gene was for the first time sequenced in eelpout species of the genus Zoarces from the Taui Bay of the Sea of Okhotsk: notched-fin Z. elongatus Kner, 1868 and the new sympatric form Zoarces sp., differing in a large set of morphological traits. The two species were compared with European eelpout Z. viviparus Linnaeus, 1758 from the Finnish Bay of the Baltic Sea. Divergence and phylogenetic analyses demonstrated a greater genetic similarity between Zoarces sp. and Z. viviparus than between sympatric Zoarces sp. and Z. elongatus.     

Individual optimization: Mechanisms shaping the optimal reaction norm

In general, optimal reaction norms in heterogeneous populations can be obtained only by iterative numerical procedures (McNamara, 1991; Kawecki and Stearns, 1993). We consider two particular, but biologically plausible and analytically tractable cases of individual optimization to gain insight into the mechanisms which shape the optimal reaction norm of fecundity in relation to an environmental variable or an individual trait. In the first case, we assume that the quality of the environment (e.g. food abundance) or the quality of the individual (e.g. body size) is fixed during its entire life; it may also be a heritable individual trait. In the second case, individual quality is assumed to change randomly such that the probability distribution of quality in the next year is the same for the parent and for her offspring. For these two cases, we obtain analytical expressions for the shape of the optimal reaction norm, which are heuristically interpretable in terms of underlying selective mechanisms. It is shown that better quality may reduce the optimal fecundity. This outcome is particularly likely if better quality increases a fecundity-independent factor of parental survival in a long-lived species with fixed quality. This revised version was published online in July 2006 with corrections to the Cover Date.     

Nucleotide sequence variation of the mitochondrial COI gene in several eelpout species of the genus Zoarces (Zoarcidae, Pisces)

The mitochondrial COI gene was for the first time sequenced in eelpout species of the genus Zoarces from the Taui Bay of the Sea of Okhotsk: notched-fin Z. elongatus Kner, 1868 and the new sympatric form Zoarces sp., differing in a large set of morphological traits. The two species were compared with European eelpout Z. viviparus Linnaeus, 1758 from the Finnish Bay of the Baltic Sea. Divergence and phylogenetic analyses demonstrated a greater genetic similarity between Zoarces sp. and Z. viviparous than between sympatric Zoarces sp. and Z. elongatus.     

Finding of the shantar snailfish Liparis schantarensis (scorpaeniformes: Liparidae) in the taui bay region of the Sea of Okhotsk

Six specimens of the Shantar snailfish Liparis schantarensis are found in the Taui Bay region of the Sea of Okhotsk for the first time. The new location is approximately midway between two the previously known areas of habitation of the species. The mature males of Shantar snailfish show two peculiarities which were not noted for the species until now: the essential lengthening of rays of the anterior dorsal fin, and the presence of skin spines on the body.