ALBERT

Beschreibung: Mechanisms that affect thermal tolerance of ectothermic organisms have recently received much interest, mainly due to global warming and climate-change debates in both the public and in the scientific community. In physiological terms, thermal tolerance of several marine ectothermic taxa can be linked to oxygen availability, with capacity limitations in ventilatory and circulatory systems contributing to oxygen limitation at extreme temperatures. The present review briefly summarizes the processes that define thermal tolerance in a model cephalopod organism, the cuttlefish Sepia officinalis, with a focus on the contribution of the cephalopod oxygen-carrying blood pigment, hemocyanin. When acutely exposed to either extremely high or low temperatures, cuttlefish display a gradual transition to an anaerobic mode of energy production in key muscle tissues once critical temperatures (Tcrit) are reached. At high temperatures, stagnating metabolic rates and a developing hypoxemia can be correlated with a progressive failure of the circulatory system, well before Tcrit is reached. However, at low temperatures, declining metabolic rates cannot be related to ventilatory or circulatory failure. Rather, we propose a role for hemocyanin functional characteristics as a major limiting factor preventing proper tissue oxygenation. Using information on the oxygen binding characteristics of cephalopod hemocyanins, we argue that high oxygen affinities (= low P50 values), as found at low temperatures, allow efficient oxygen shuttling only at very low venous oxygen partial pressures. Low venous PO2s limit rates of oxygen diffusion into cells, thus eventually causing the observed transition to anaerobic metabolism. On the basis of existing blood physiological, molecular, and crystallographical data, the potential to resolve the role of hemocyanin isoforms in thermal adaptation by an integrated molecular physiological approach is discussed.

Beschreibung: The functional response of Sepia officinalis early stages, preying on mysids of the species Mesopodopsis slabberi was investigated. The effects of five prey densities (12.5, 25, 37.5, 50 and 125 mysids l−1) and two hatchling ages (1-day-old and 7-day-old) on consumption rate and the frequency of non-feeding animals were tested. Older animals were approximately 50% heavier than newly hatched ones. Hatchlings were individually assayed under 0.25 W m−2 natural light, 37.8 psu in salinity and 19°C. The effect of prey density on consumption rate was highly significant and no effect of age was detected within the age range tested. Maximal values recorded for consumption rate were about 0.45 mysids h−1. The frequency of non-feeding individuals was strongly reduced at saturating prey densities. The functional response curve showed an interval of prey densities for which density-dependent prey mortality is probable.

Beschreibung: Recent molecular studies investigating higher-level phylogenetics of coleoid cephalopods (octopuses, squids and cuttlefishes) have produced conflicting results. A wide range of sequence alignment and analysis methods are used in cephalopod phylogenetic studies. The present study investigated the effect of commonly used alignment and analysis methods on higher-level cephalopod phylogenetics. Two sequence homology methods: (1) eye alignment, (2) implied alignment, and three analysis methods: (1) parsimony, (2) maximum likelihood, (3) Bayesian methodologies, were employed on the longest sequence dataset available for the coleoid cephalopods, comprising three mitochondrial and six nuclear loci. The data were also tested for base composition heterogeneity, which was detected in three genes and resolved using RY coding. The Octopoda, Argonautoidea, Oegopsida and Ommastrephidae are monophyletic in the phylogenies resulting from each of the alignment and analysis combinations. Furthermore, the Bathyteuthidae are the sister taxon of the Oegopsida in each case. However many relationships within the Coleoidea differed depending upon the alignment and analysis method used. This study demonstrates how differences in alignment and analysis methods commonly used in cephalopod phylogenetics can lead to different, but often highly supported, relationships.

Beschreibung: We report data on the stomach contents of the long‐finned pilot whale, Globicephala melas, recovered from a group of whales stranded on Ruakaka Beach, northeastern New Zealand, in November 2006. In nine whales for which identifiable stomach contents were recovered (three that stranded on 10 November and six that stranded on 11 November) prey remains comprised exclusively cephalopod beaks attributed to five squid species. The stomachs of a further two whales contained unidentifiable upper beaks only, while the stomachs of five whales were completely empty. No whale appeared to have been satiated immediately before stranding, given that the maximum biomass of prey recently consumed by any one whale was calculated to be 〈5 kg. All squids ingested represented oceanic species, found from 50 to 1000 m but more common towards the deeper end of this range. These data both complement and contrast with the only other dietary information available for this species in New Zealand waters, reported from stomach contents of whales stranded on Farewell Spit, South Island in December 2005.

Beschreibung: Stomach contents of the long‐finned pilot whale, Globicephala melas, are reported for the first time from New Zealand waters. Analyses based on two male and three female whales (2.5–5.3 m in length) that stranded on Farewell Spit, Golden Bay, South Island in December 2005 revealed a diet comprised exclusively of cephalopods (2-33 lower cephalopod beaks per stomach). Two genera of cephalopod from two orders; arrow squid, Nototodarus spp. (Teuthoidea: Ommastrephidae), and common octopus, Pinnoctopus cordiformis (Octopoda: Octopodidae) were represented. A further five pilot whale stomachs were examined and found to be empty.

Beschreibung: Stomach contents of a resident community of bottlenose dolphins (Tursiops truncatus) from the Sarasota Bay area of the westcentral coast of Florida were studied to examine potential factors leading to patterns of habitat use. Composition and size of prey were analyzed and correlated with feeding behavior of individual dolphins of known histories. Examination of stomach contents of 16 stranded dolphins revealed a diet composed exclusively of fish (15 species), most of which were associated with seagrasses in varying degrees. Observational records for 21 years showed that feeding typically occurred in shallow (2–3 m) waters and in the vicinity of seagrasses in 23% of cases. Dolphins usually fed alone or in small groups and on non-obligate schooling prey. The main species of prey were soniferous, an indication that passive listening may be important in detection of prey. The close agreement between species of fishes represented in stomach contents and habitat of prey, as indicated by observations of feeding, suggests that analysis of stomach contents is a reasonable approach for studying prey and feeding patterns of dolphins. Meadows of seagrass are one of the habitats of importance to dolphins in the Sarasota Bay area, and their protection is important for conservation of these animals.

Beschreibung: The highly active squid which inhabit the pelagic zones of continental seas are characterized by high energy requirements and have been termed invertebrate athletes. In this paper, the physiological and biochemical background of muscular performance in squid from different environments is reviewed and the physiological and environmental factors limiting performance levels are addressed. One important factor is the highly concentrated haemocyanin which, in ommastrephid squid, and by virtue of their extreme pH dependence, helps to load oxygen efficiently in the gills and unload it fully into the tissues. Squid regulate their extracellular pH more efficiently than intracellular pH, so protecting the haemocyanin from fatal pH changes. However, a large proportion of the oxygen requirement in the mantle muscle must still be provided by oxygen uptake through the skin. Anaerobic mechanisms become involved beyond critical swimming speeds once oxygen supply to mitochondria becomes limiting. Onset of anaerobiosis also characterizes the limits of long-term tolerance to progressive hypoxia at a critical P O2 and to high, above-critical temperatures. In general, anaerobic energy production reflects an inability to meet oxygen demand and indicates transition to a time-limited situation. The development of energy-saving locomotion strategies therefore shifts critical thresholds and extends tolerance periods in species exposed to environmental extremes, typically in coastal areas. There, negatively buoyant squid make greater use of the fin for economical swimming, which is also advantageous because of the complexity of the environment. In Lolliguncula brevis, the rate at which anaerobic resources are used above the critical swimming velocity is minimized by oscillating between periods of high and low pressure jets, thereby extending the period during which the animal can dive into hypoxic or warm water. However, only jet propulsion can economically attain the high velocities necessary in the open sea. Accordingly, the highest performance levels are seen in squid inhabiting the open sea, and they are only made possible by the uniform environmental parameters. Some squid may be able to operate at their functional and environmental limits, revealing a trade-off between oxygen availability, temperature, performance level and, possibly, body size.

Beschreibung: A peculiar squid paralarva from Hawaiian waters was described by Young (1991, Bull. mar. Sci. 49(1–2): 162–185), but it could not be assigned to any known family. Two larger juvenile specimens have now been obtained, one collected near the surface in the eastern Pacific Ocean and the other rehydrated from a dried specimen originally recovered from the stomach of an Alepisaurus. A photograph of the latter specimen before dehydration was found among the unpublished notes of S. S. Berry. The squid are characterized by very large fins that dwarf the rest of the animal. The fins are terminal in position, mostly posterior to the mantle muscle. The tentacles are similar to the arms in general form, but are much more robust. Tentacle suckers are in eight series, whereas the crowded arm suckers constitute more than two series on some arm pairs. The distal portions of the arms and tentacles taper abruptly to thin vermiform filaments. The funnel cartilage of the net-collected juvenile is oval and the buccal connectives to Arms IV are ventral. Although some characters indicate a likely relationship with the chiroteuthid/mastigoteuthid group of families, the brachial crown differs from that found in any known family. Based upon these three specimens and the photograph, it is concluded that the squid represent a family not previously recognized by science. This family is named Magnapinnidae, with the type species Magnapinna pacifica n. gen., n. sp., the holotype of which is the net-collected juvenile. Although all three specimens are included in the family and genus, the possibility exists that the paralarva and the rehydrated specimen are not conspecific with the holotype. Therefore, paratypes are not designated.

Beschreibung: Cephalopod eggs and egg masses turn up in samples taken during oceanographic cruises (including subsamples consisting of the stomach contents of marine predators); they are encountered by Scuba divers and crews of manned submersibles, and stranded egg masses can be found on ocean beaches around the world. If it is comparatively easy to identify such material as "squid eggs", it is much more difficult to recognize the group or species to which the eggs belong. There are various reasons why the identification of eggs and egg masses is often difficult or impossible, especially for the non-specialist. The lack of standardized illustrated keys showing both the embryonic stages and the corresponding aspects of egg capsules for well known species is a major impediment to identification or further developments needed to optimize the chances of finding hitherto unknown material...