ALBERT

Description: The enoploteuthid cephalopod Abraliopsis lineata is re-described and its generic position discussed. Specimens for the present study were captured during the Indian Ocean Expedition of RV Meteor in 1987, where the species occurred in considerable numbers. The geographical distribution of A. lineata is described and discussed. The detailed analysis of the photophore pattern of the present specimens differs from the original description. The diagnostic features in the male, especially the structure of the hectocotylus which separates A. lineata easily from the members of the subgenus Pfefferiteuthis, are outlined. The morphological differences which separate A. lineata from A. gilchristi, the only other member of the subgenus Micrabralia, are summarized.

Description: A detailed analysis of lower rostral beak length (LRL) to body size and wet body mass measurements was carried out for the squids Loligo forbesi, Todarodes sagittatus and Todaropsis eblanae. Specimens were sampled in the northern North Sea during two research cruises of FRV WALTHER HERWIG III in January/February of 1998 and 1999. Altogether 241 specimens of Loligo forbesi (ML = 45–376 mm), 108 specimens of Todarodes sagittatus (ML = 173–325 mm) and 97 specimens of Todaropsis eblanae (ML = 30–127 mm) were investigated to correlate lower rostral beak length with both mantle length and wet body mass. Linear relationships between LRL and mantle length and powerfunctional relationships between LRL and wet body mass were calculated for all three species. By calculating these correlations separately for males and females, no obvious sex-specific relationships were found. The presented data will upgrade the information on beak/mantle length/body mass relationships of major cephalopod species of the North Sea. They provide essential information for future use in estimates of cephalopod prey biomass in North East Atlantic top predators such as whales, seals, seabirds and fishes.

Description: From April to June of 1987 R/V Meteor collected zooplankton and micronekton samples in the northeastern part of the Arabian Sea. One hundred and fifty-seven cephalopod specimens were captured by oblique IKMT hauls through water depths from 1,000 to 0 m and identified to the lowest possible taxon. Thirteen species of nine families were recorded. The majority of the specimens were early life stages of pelagic oceanic species. The cranchiid squid Liocranchia reinhardti was the dominant form (108 specimens) followed by the enoploteuthid squids Abraliopsis lineata (22) and Abralia marisarabica (9). Size-frequency compositions and maps of the geographical distribution are compiled for the most abundant species. The data reveal a tropical cephalopod fauna and will improve the poor knowledge on the distribution patterns of pelagic cephalopods in the Indian Ocean.

Description: The capture of 52 specimens of the cirrate octopod Grimpoteuthis glacialis (Robson, 1930), of dorsal mantle length 20-165 mm during a 1996 trawling survey near the Antarctic Peninsula allowed the basic biology of the species to be examined. Their presence in bottom trawls at depths of 333-879 m, but their absence from benthopelagic and pelagic trawls, is consistent with a primarily benthic habitat. The largest single sample, 40 animals, came from a soft mud bottom and highlights the patchy nature of the distribution. Males tended to be bigger in total length and mass than females of similar mantle length. The males, however, were mature at a smaller size. Mature males have tiny sperm packets, rather than typical cephalopod spermatophores, in their distal reproductive tract. Mature females have large, smooth eggs in the proximal oviduct, in the huge oviducal gland and in the distal oviduct. Eggs in the distal oviduct have a thick, sticky coating that hardens in seawater into a secondary egg case. Ovarian eggs vary greatly in size, possibly indicating protracted egg laying. Observations on live animals indicate that the species swims primarily by fin action, rather than by jetting or medusoid pulses with the arm/web complex. It may be capable of limited changes in colour pattern, especially on the oral surface of the web. Three pairs of surface structures that appear superficially to be white spots anterior to the eyes and near the bases of the fins are actually transparent patches in the skin. When considered in association with the transparent subdermal layer and the anatomy of the eyes, optic nerves and optic lobes, these clear patches seem to function in detecting unfocused light on the horizontal plane of the benthic animal.

Description: Some 290 species of squids comprise the order Teuthida that belongs to the molluscan Class Cephalopoda. Of these, about 30-40 squid species have substantial commercial importance around the world. Squid fisheries make a rather small contribution to world landings from capture fisheries relative to that of fish, but the proportion has increased steadily over the last decade, with some signs of recent leveling off. The present overview describes all substantial squid fisheries around the globe. The main ecological and biological features of exploited stocks, and key aspects of fisheries management are presented for each commercial species of squid worldwide. The history and fishing methods used in squid fisheries are also described. Special attention has been paid to interactions between squid fisheries and marine ecosystems including the effects of fishing gear, the role of squid in ecosystem change induced by overfishing on groundfish, and ecosystem-based fishery management.

Description: A two-leg cruise of R/V G. O. Sars in summer of 2004 along the Mid-Atlantic Ridge explored the diversity and distribution patterns of pelagic and non-hydrothermal bottom communities in the vicinity of the northern Mid-Atlantic Ridge. In total, 1295 cephalopods were caught, representing 56 species. Differences in species composition and size were apparent among the various types of trawls used. The Aakra trawl and bottom trawl caught the largest numbers of species (38 and 34, respectively); size of cephalopods was directly related to the size of the net. Many more species were caught in the southern part of the study area than farther north. The most abundant species was Gonatus steenstrupi, found mostly in the northern part of the study area. A few abundant species, such as Mastigoteuthis agassizii, were found throughout the region, with no clear indication that their northern or southern distributional limits occur within the area sampled. Several benthic and one pelagic species, all taken in small numbers, were captured only in the region of the Charlie Gibbs Fracture Zone. We found many species at very low numbers (i.e. 37 species with 〈10 specimens in all gear types combined).

Description: Beaks of 133 specimens of Todarodes sagittatus caught in the central East Atlantic were studied. Relationships between several measurements of the upper and lower beaks and dorsal mantle length (DML) and total mass were calculated. The darkening process or pigmentation of both beaks was investigated and a qualitative scale of eight degrees of pigmentation developed. Except for the hood of the lower beak, the growth of both beaks was allometrically negative in relation to DML in males, whereas the growth of several parts of both beaks of females was allometrically positive. The hood grew faster than all other parts of the male beak and faster than all parts of the lower beak of females. Regression coefficients calculated for the growth of the beaks revealed differences between the growth patterns of females and males (p 〈 0.05). The results relating to darkening and the maturing process suggest that they are related and that they take place over a very short period in the life of the squid.

Description: Cephalopods play a significant role in coastal and oceanic ecosystems, both as consumers of invertebrates and small fish and as the prey of some fish, seabirds and marine mammals and other large predators. Approximately 30 species of cephalopod have been recorded in the north-eastern Atlantic and adjacent waters, including 18 teuthid (squid), seven sepiolid (bobtail), three sepiid (cuttlefish) and 10 octopod (octopus) species. A number of these are exploited commercially and support important target and by-catch fisheries in Western Europe. During the past decade, annual landings of cephalopods from the north-eastern Atlantic (International Council for the Exploration of the Sea [ICES] area) have ranged from 40,000 to 55,000 t, including substantial catches of long-fin (loliginid) squid (7000–11,000 t per annum), short-fin (ommastrephid) squid (3000–10,000 t), cuttlefish (including sepiolids; 16,000–24,000 t) and octopods (12,000–18,000 t). The most important exploited species in the north-eastern Atlantic are Eledone cirrhosa, Illex coindetii, Loligo forbesi, Loligo vulgaris, Octopus vulgaris, Todarodes sagittatus, Todaropsis eblanae and Sepia officinalis. Other species including Alloteuthis subulata, Gonatus fabricii and certain sepiolids, appear to be abundant and may be marketable. Cephalopods tend to rapidly concentrate heavy metals and other toxic substances in their tissues and this plays an important role in the bioaccumulation of these pollutants in marine predators as well as having implications for human consumption. High levels of cadmium and mercury are often recorded in cephalopod tissues. Another important environmental issue concerns the potential impact of widespread human activity on cephalopod spawning areas, particularly bottom-fishing operations but also shipping, and oil exploration and production. In contrast to many finfish species that spawn annually over a number of years, most cephalopods live only 1–2 yr and die after spawning. Therefore, failure to reproduce and recruit adequately in any given year may seriously impact the long-term viability of cephalopod stocks. Climate change is expected to have a significant effect on many species in the north-eastern Atlantic. This review provides a detailed account of the zoogeography, biology and ecology of cephalopods in the north-eastern Atlantic, on a species-by-species basis. Important economic, ecological and conservation issues affecting cephalopods in this area are also discussed