ALBERT

Description: The squid Gonatus fabricii (Lichtenstein, 1818) is the most abundant pelagic cephalopod in the Arctic and the only squid to spend all of its life cycle in this region. Despite being highly abundant, its reproductive biology remains poorly known, and data on large maturing and mature specimens are especially rare. This study, based on extensive material (51 large specimens and 〉35,000 specimens in all), fills major gaps in the knowledge of the reproductive biology and ecology of G. fabricii. The fecundity of females ranged from 8,862 to 16,200 oocytes, with mature and late maturing specimens having between 8,862 to c. 10,000 and 11,402 oocytes, respectively. Oogenesis was synchronous, and oocyte resorption was observed; resorbed oocytes constituted up to 23.5% of fecundity. Between two to five ripe oocytes were observed, and these were 4.0–5.5 mm in diameter (maximum dimension). Males possessed between 77 and 257 spermatophores (length = 5.8–10.8 mm). Spermatophores were characterized by a cement body with well-developed collar and discs at the oral end, an ejaculatory apparatus longer than the cement body and the lack of a tapered, sharp tip to the cement body. Spermatophore size showed a uniform increase in relation to increasing male size. In newer spermatophores, the length, width and volume of the seminal reservoir also increased. Females possessed between 62 and 84 spermatangia (length = 1.8–2.6 mm); the spermatangia were present on the buccal membranes and lacked special attachment structures. Seminal receptacles were not found on the buccal membranes of females. Our findings are consistent with the hypothesis of geographically restricted spawning in G. fabricii. The study found evidence for one new breeding area in south-eastern Greenland. No differences in sizes at maturity were found between the breeding areas. Such geographically localized reproduction is relatively common in non‐deep-water squids, but is much less common in deep-water squids. Localized reproduction may be especially important for G. fabricii because increased food availability in the epipelagic layers would likely increase the survival of epipelagic juveniles, with surface currents potentially aiding in their dispersal.

Description: Data obtained using three different types of sampling gear is compared and combined to assess the size composition and density of a non-indigenous snow crab population Chionoecetes opilio in the previously free of alien species Kara Sea benthos. The Sigsbee trawl has small mesh and catches even recently settled crabs. The large bottom trawl is able to catch large crabs, but does not retain younger crabs, due to its large mesh. Video sampling allows the observation of larger crabs, although some smaller crabs can also be spotted. The combined use of such gear could provide full scope data of the existing size groups in a population. The density of the crabs was calculated from the video footage. The highest figures were in Blagopoluchiya Bay at 0.87 crabs/m2, where the settlement seems to be reaching its first peak of population growth after the introduction. High density in the Kara Gates Strait at 0.55 crabs/m2, could be due to the close proximity of the Barents Sea from where the crabs can enter by both larval dispersal and active adult migration. All size groups have been present in most sampled areas, which suggest successful settlement and growth of crabs over a number of years. Again, this was not the case in Blagopoluchiya Bay with high density of small crabs (

Description: We report two Arctic species of incirrate octopods new to science. One is formally described here as Muusoctopus aegir Golikov, Gudmundsson & Sabirov sp. nov. while the other, Muusoctopus sp. 1, is not formally described due to a limited number of samples (all are immature individuals). These two species differ from each other, and from other Muusoctopus, especially in: 1) absence of stylets (in M. aegir sp. nov.); 2) proportions of mantle and head; 3) funnel organ morphology (W-shaped with medial and marginal limbs of equal length in M. aegir sp. nov., or medial are slightly longer; V V-shaped with medial limbs slightly longer and broader than marginal in Muusoctopus sp. 1); 4) sucker and gill lamellae counts; 5) relative arm length and sucker diameter; and 6) male reproductive system relative size and morphology. Species of Muusoctopus now comprise four of 12 known Arctic cephalopods. Additionally, this study provides: a) new data on the morphology and reproductive biology of M. johnsonianus and M. sibiricus, and a diagnosis of M. sibiricus; b) the equations to estimate mantle length and body mass from beak measurements of M. aegir sp. nov. and M. johnsonianus; c) a cytochrome c oxidase subunit I gene barcode for M. sibiricus; d) new data on the ecology and distribution of all studied species; and e) a data table for the identification of northern North Atlantic and Arctic species of Muusoctopus.