Search

Cytoplasmic pH (pHi) of haemocytes of bigfin reef squid (Sepioteuthis lesso-niana Lesson) was determined with the fluorescent probe, 2′,7′-biscarboxyethyl-5,6-carboxyfluorescein (BCECF). The pHi of haemocytes suspended in nominally HCO3−-free medium (extracellular pH 7.4) averaged (±S.E.) 7.32±0.02. Intracellular pH was independent of external Na+ concentration and varied only slightly with changes in extracellular pH (pHe) (ΔpHi/ΔpHe=0.16 over the pHe range 6.8–7.8). Addition of weak acids (sodium propionate, potassium acetate) to haemocyte suspensions resulted in a rapid decrease in pHi. Haemocyte pHi then recovered with an average half-time of 3–4 min. Recovery of pHi was independent of external Na+ concentration and insensitive to amiloride, but was abolished by N-ethylmaleimide (NEM). These results argue against the involvement of plasma membrane Na+/H+ exchange or other Na+-dependent transport mechanisms in the pHi recovery of acid-loaded haemocytes. The results suggest that there is an NEM-sensitive proton extrusion mechanism in the plasma membrane of squid haemocytes.

Food consumption, food conversion and growth rates of the oval squid Sepioteuthis lessoniana were measured on an individaul basis fed on three kinds of live organisms, namely, fish, mysid and squid hatchling. Squid used in the present study were all reared from egg to the experimental size, ranged from 0.06 to 42.1g in wet body weight in an indoor aquarium. The daily food con-sumption rate ranged from 0 to 72% of body weight and depended upon the growth stage of the squid. Food conversion rate on a wet weight basis ranged from 15.4 to 43.8% and the rate was largely independent of the size of squid. Growth rate of the oval squid decreased with increasing size. The daily growth rate in body weight of hatchling reached 12.9% and that of the squid grown up to 30-50g in body weight ranged from 1.8 to 4.1%. The growth was dependent upon quality of food. Squid fed on squid hatchlings showed the highest growth rate followed by those fed on fish. The daily growth rate increased with each increment of the daily food consumption rate.

This study demonstrates the simultaneous use of acoustic and archival tags for obtaining data for near-shore species. Australian giant cuttlefish Sepia apama (off Whyalla, South Australia) and the tropical squid Sepioteuthis lessoniana (off Magnetic Island, Queensland, Australia) were tagged using a ‘hybrid’ tag consisting of a Vemco V8 acoustic tag potted with a Vemco minilog temperature–depth archival tag. Four of these animals were released and monitored inside radio-acoustic-positioning-telemetry (RAPT) buoy-system arrays that included bottom-mounted sensors that transmitted independent temperature records and a reference standard for sound conductivity and position. All were subsequently located out of RAPT range and two of the four archival tags were recovered. Tags were located using a boat-mounted hydrophone and VR60 receiver and recovery was aided by a diver operating a hand-held VUR96 receiver. This technology provides a cost-effective alternative to expensive satellite pop-up tags and is suitable for much smaller species that return to near-shore environments.

Previous observations on the mating behaviour of the southern calamary, Sepioteuthis australis Quoy & Gaimard 1833, revealed the potential for multiple paternities within egg strands, which contained up to eight eggs each. Six egg masses were laid in captivity from a possible 14 female and 20 male parents. By using five microsatellite loci, 112 eggs from 35 randomly selected egg strands were assigned sires using the potential fathers’ genotypes. Seven egg strands containing 22 eggs were also collected from the field to test that squid in captivity were apportioning eggs in natural ways, and that multiple paternity within egg strands was not an artefact of captivity. Ninety-seven per cent of strands laid in captivity showed multiple paternities. Similarly, multiple fathers were also evident in the field-laid egg strands. The maximum number of sires found within a single egg strand was four; however, three sires were more common. This is the first account of multiple paternities within egg strands laid by Sepioteuthis. It is likely that females are ‘spermatophore-limited’ when egg laying, and are promiscuous to ensure a ready supply of these sperm packets. Moreover, genetic diversity in a brood is increased by this mating strategy.

Recent years have seen the emergence of extensive studies of myopsid squid growth of the family Loliginidae. This has greatly advanced our understanding of their life histories. Growth data have accumulated from both statolith-based field studies and culture work. Validation studies on loliginids continue to support that statolith increments are laid down daily. Ageing work has also revealed that short lifespans are typical, with nine of the 21 species studied having lifespans 1 year. While growth is continuous and non-asymptotic, the marked plasticity in size-at-age has hindered the development of a general model to describe squid growth. Many loliginids are multiple spawners that continue to feed while growing and reproducing, although there has been some documented loss of conditon in mature individuals. An exception is Loligo opalescens, which has a terminal spawning strategy with a marked loss of condition and post-spawning mortality. Quantification of the cost of living and the energetics of loliginids are likely to be best achieved by combining field and culture studies on a species such as the Indo-Pacific squid Sepioteuthis lessoniana.

Light microscopical observation of serial sections of four kinds of decapoda which living in seas around Japan (Ommastrephes sloanei pacificus, Sepia esculenta, Doryteuthis bleekeri, Sepioteuthis lessoniana) was carried out. These specimens were fixed alive with 10% formaldehyde solution diluted with sea water and then dehydrated without decalcification with ethylalcohol diluted with sea water. After embedding in 6% celloidin, the specimens were cut into 30 microns thick and sections were stained with hematoxilineosin. Under light microscopic observation, the maculae, statoconial layers, cristae, cupulae, statoliths, central nervous system and static nerves were well preserved. The statocysts of all four decapod species were similar in shape. Color photographs of horizontal sections of the head, statocysts, processes, gravity recepter systems, angular acceleration receptor systems, statoliths and nerve fibers with the central nervous system of these four decapod species are shown.

Demersal trawl and dredge surveys of the Gulf of Carpentaria in the early summers of 1990 and 1991 provided the first comprehensive assessment of the cephalopod fauna of this shallow, tropical basin off northern Australia. Twenty-one taxa (comprising five loliginid squids, seven cuttlefishes, seven octopuses and two dumpling squids) were recorded. In addition to hosting species distributed broadly in the Indo-West Pacific (e.g. loliginid squids Sepioteuthis lessoniana, Photololigo cf. chinensis and P. cf. edulis; cuttlefishes Sepia eiliptica and Sepia pharaonis), the Gulf of Carpentaria represents the most northwesterly extent of the range of some eastern Australian species (e.g. Loliolus noctiluca and Sepia whitieyana). Squid catches were lower in the north-western gulf in 1990 and higher in shallower water during the more geographically restricted survey in 1991, whereas cuttlefish were more evenly distributed throughout the different sampling areas in both years. Broad size ranges of both sexes of the four most abundant species (P. cf. chinensis (northern form), P. cf. eduiis, S. eiliptica and S. pharaonis) are indicative of extended spawning seasons, and fully mature individuals of these species were evident throughout the gulf. Cephalopods are a minor component in reported domestic fisheries catches from the Gulf of Carpentaria, where penaeid prawns are targeted. High (though seasonal) squid catch rates were reported annually by Taiwanese trawlers targeting butterfish and squid from certain areas prior to 1979. With the observed population structure of the abundant cephalopod species and relatively high catch rates in some localities during these recent surveys, it is suggested that the cephalopod resources of the Gulf of Carpentaria could support increased commercial fisheries exploitation.

Acetyltransferase enzymatic activity was detected and measured in homogenates obtained from intact nerve fibers and their separate cellular components, in the tropical squid Sepioteuthis sepioidea. The levels of acetylcholine synthesis were determined in pooled samples of whole stellar nerve, intact giant nerve fiber, extruded axoplasm, axoplasm-free giant nerve fiber sheaths, and small nerve fibers. The values found per mg of protein for the axoplasm-free sheaths are about 3–9 times those of the extruded axoplasm, and comparable to those found for the intact giant nerve fiber. These experimental findings settle the question of whether the Schwann cells of the giant nerve fiber of S. sepioidea, under physiological conditions, contain acetyltransferase activity and are able to synthesize acetylcholine.

The effect of tetrodotoxin on the sodium currents of the squid (Doryteuthis plei and Sepioteuthis sepiodea) giant axons was studied under potential control conditions. The axons were immersed in artificial seawater at 21 degrees C and pH 7.5. When the effect of the toxin is studied in concentrations ranging from 0.1 to 50 nM the Eadie-Haldane plot is not a straight line and indicates that there are two populations of sodium channels open during activity. 19.0 +/- 4.7% of the channels are accociated to receptors with an apparent dissociation constant of 0.11 +/- 0.05 nM and 84.0 +/- 4.1% of the channels are related to receptors having an affinity constant of 4.90 +/- 0.49 nM (nine nerves).

The purple hemocyanin formed on addition of a large quantity of ethyleneglycol to Sepioteuthis lessoniana oxyhemocyanin was characterized on the basis of various spectroscopic data such as the absorption, CD, esr, and Raman spectra. The purple hemocyanin is considered to be in an equilibrium state between the faintly denaturated species (ca. 60%) that is directly related with the purple color and the intensely denaturated species (ca. 40%) containing esr-detectable copper(II). The esr spectra suggest that the copper(II) exists as a mononuclear complex, that contains four nitrogeneous ligands.

INTRODUCTIONWild-caught squids have seldom survived for very long in laboratory aquaria. Tardent (1962) maintained Loligo vulgaris Lamarck, 1789 for a maximum of 60 days. Choe & Oshima (1963), Choe (1966) and LaRoe (1971) reared squids of the genus Sepioteuthis from eggs to adult size. Between 1975 and 1982 several successful attempts to maintain Loliginidae (e.g. Matsumoto, 1976; Hanlon, Hixon & Hulet, 1978, 1983; Yang et al. 1980, 1983) and Ommastrephidae (Flores et al. 1976; Flores, Igarashi & Mikami, 1977; O'Dor, Durward & Balch, 1977) were made. But to date only ten squid species have been maintained for more than forty days (review: Yang et al. 1980; Boletzky & Hanlon, 1983). Loligo opalescens Berry, 1911 holds the record for longevity in captivity at 233 days from egg to adult (Yang et al., 1983).

Growth, life span and spawning season of the oval squid Sepioteuthis lessoniana were studied in the outer waters adjacent to the Kii Channel, Japan. The spawning season was estimated during June to September. The von Bertalanffy's equations were applied to monthly size compositions. They were Lt=23.2[1-exp{-0.354(t+0.044)}] for female and Lt=25.7[1-exp{-0.408(t-0.063)}] for male, where Lt was mean mantle length (cm) at t months after hatching in August. These growth rates were much larger than those observed in aquaria. The life span was one year: S. lessoniana hatched out in summer and died just after spawning in next summer.

Some of the features of the behaviour of Sepioteuthis are described compared with that of other squids and of cuttlefish which it has come to resemble.

A technique for rearing the loliginid squids Sepioteuthis sepioidea and Doryteuthis plei is reported. Specimens of the former were reared from eggs to sexually mature adults, and maintained for a maximum of 146 days; adult D. plei were maintained for 38 days. Choice and quantity of food was most important for the survival of all sizes, particularly young squid. Newly hatched specimens thrived on Mysidium columbiae. Both species fed at a rate of 30 to 60% of their body weight daily; starvation occurred when intake fell below 10 to 15%. Food conversion efficiency averaged between 10 to 20%. Growth was rapid and steady. S. sepioidea grew to a maximum of 105 mm and 77 g in less than 5 months; D. plei grew an estimated 20 mm/month. Experimental data indicate a lethal minimum salinity for both species at about 27‰. Lethal minimum and maximum temperatures for young S. sepioidea are 17.5° to 18.0°C, and 32.5° to 33.0°C, respectively. Young consume 0.64μl O2/mg wet weight/h. Opaque tanks, with a semi-natural bottom substrate and special ultra-violet (UV) illumination, are advantageous for rearing and maintenance.

In the Fumoto's method, octopine is freed from arginine by the preliminary treatment with an Amberlite IRC-50 resin (pH 4.7) and photometrically determined by a modified method of Sakaguchi reaction. Applicability of this method was examined for the determination of octopine in squid muscle. As a result of the test using squid muscle extracts, recovery of added octopine was 90.9 ?? 97.9% (Table 1). Subsequent experiments in which octopine and free arginine were determined from the muscle extracts of two species of squid, revealed the following points. (1) A sample of Ommastrephes sloani pacificus STEENSTRUP contained free arginine smaller and octopine larger in amount than a ample of Sepioteuthis lessoniana FERUSSAC (Table 2). (2) However, the total amount of the substances always constituted one third of the extractive nitrogen in the muscles, regardless of the different species. (3) During the storage of Sepioteuthis lessoniana FERUSSAC at 5° ?? 7°C, free arginine rapidly decreased and octopine increased in the muscle (Fig. 1). From these results, the species-difference observed in the amount of octopine or free arginine in squid muscle was supposed to be due to either one of the following; post mortem duration is different between materials used, or rate of conversion of free arginine to octopine varies between species of the squid.

Literature dealing with laboratory studies of live squid usually includes a statement that attempts to rear or maintain squid in aquaria are unsuccessful. When stated, the survival of squid in captivity is most often given for the longest lived individual and predictive survival rates are not specified. A considerable body of current research (principally that dealing with squid "giant axons") depends on a reliable supply and short term maintenance of squid. Several aspects of squid biology lag for want of effective means to carry out lengthy laboratory studies. Preparatory to possible future studies on the maintenance of the squid, Loligo pealei (Lesueur, 1821), we have observed squid survival when subjected to standardized conditions. Quantitative data were obtained in an attempt to specify survivorship for comparison with other reports and for evaluation of certain environmental factors. The most dramatic results of attempts to rear cephalopods were reported by Choe (1966), who succeeded in fostering a few individuals of three species for more than 100 days and one loliginid squid for over 40 days. Edward T. LaRoe (University of Miami, unpublished) has repeatedly reared Sepioteuthis sepioidea to near maturity. Adults of this species have been maintained in floating pens for two months and possibly longer (Arnold, 1965). Immature squid, Loligo vulgaris, were reported to survive captivity for several weeks (Bidder, 1950) and for two months (Tardent, 1962). Tardent (1962) stated that sexually mature L. vulgaris do not normally live more than two weeks in the Naples Aquarium. Bidder (1950) reported that L. vulgaris is less sensitive to handling than Loligo forbesi and quoted a Dr. Sereni in the opinion that L. pealei at Woods Hole is far hardier and more resistant to handling than L. vulgaris at Naples. Roper (1965) reported a female Doryteuthis plei which survived 18 days in an aquarium, laying two egg masses in that time. Arnold (1962) gives the survival of sexually mature L. pealei as about five days and one instance of a male surviving for 17 days. These survival times refer to the longevity of the last remaining individual. In all of the references cited, squid were fed regularly and provided with running seawater. Only references dealing with loliginid squid have been cited because the survival of other families of cephalopods may not be comparable due to differences in life habits and ecological tolerances.

1. Two decapod cephalopoda, Euprymna (a sepiolid) and Sepioteuthis (a squid) have been tested for their orientation behavior in a vertical beam of linearly polarized light and in horizontal light intensity patterns. 2. Like many arthropods these mollusks show four preferential swimming directions relative to the e-vector (0°, 90° and ±45°) 3. Horizontal intensity patterns induce only positive or positive and negative phototactic orientation. 4. When polarized light and intensity patterns are presented together the polarized light response predominates. 5. Polarized light vision in these decapod mollusks is a distinct perceptual process showing remarkable convergence wiht this function in arthropods.

Sepioteuthis bilineata (Quoy and Gaimard, 1832) (Mollusca : Cephalopoda : Loliginidae), were observed in February 1970 laying egg capsules on an artificial reef off Goat Island, Leigh, Northland, New Zealand. The behaviour of the squid throughout the procedure of capsule placement is described. A description of the egg mass and the newly hatched squid is also given.

Free amino acids, trimethylamine oxide, and betaine in the mantle muscle of six species of squids were determined, and interesting facts on the species-difference in the amount of components were observed, as shown in Table 2 and Fig. 1. Squids having a better taste, such as Loligo chinensis GRAY, Loligo kensaki WAKIYA and M. ISHIKAWA, Sepioteuthis lessoniana FERUSSAC, and Sepia esculenta HOYLE, were rich in free amino acids, in which glycine, proline, and alanine were prominent. In some squids inferior in taste, Ommastrephes sloani pacificus STEENSTRUP and Thysanoteuthis rhombus TROSCHEL, trimethylamine oxide was the dominent component with less amount of free amino adid, with single exception in arginine, than the other species of squids. From these facts, such free amino acids, as glycine, proline and alanine are assumed to be responsible for the deliciousness of squids.

Otr experiments carried out at the Ikawazu Fisheries Laboratory, Tokyo University in 1960 proved that the fry of the squid, Sepioteuthis lessoniana, could be grown on a live mysisshrimp, Neomysis japonica, in tanks with running water, and also the rearing tried in 1961 by the same method went successfully in three species of cuttlefishes, Sepia esculenta, Sepia subaculeata and Sepiella maindroni. 1) The fry of cuttlefish and squid begin to hunt almost within 24 hours after hatching, their prey then being tiny crustaceans, such as mysis and the other larvae of shrimps. The fry of these Cephalopods appear to find sufficient nutriment in only the live mysis during the period immediately after emergence from the egg until they grow a month old. At the end of this period the fry fed sufficiently grew up to be the mantle-length of about 20mm in the cuttlefishes and 30mm in the squid. The rate of survival in every one of these species was much high, amounting to more than 80 per cent of the original fry. 2) In the Sepia and Sepiella, as they grow older, living food materials could be replaced by minced fish meat or salted mysis-shrimp placed on the bottom of tank, but such replacement seemed to be difficult in the Sepioteuthis, because they hardly cared for the dead or motionless prey. 3) Among the Sepia and other species there are some differences not only in the feeding habit as mentioned above, but in the swimming activity observed in tanks. The Sepia being rather sluggish, although S. subaculeata swims slowly about near the bottom at times, usually lie on the bottom. On the other hand the Sepiella and Sepioteuthis swim about actively and in schools.

Anion conductances of giant axons of squid, Sepioteuthis, were measured. The axons were internally perfused with a 100-mM tetraethylammonium-phosphate solution and immersed in a 100-mM Ca-salt solution (or Mg-salt solution) containing 0.3 microns tetrodotoxin. The external anion composition was changed. The membrane currents had a large amount of outward rectification due to anion influx across Cl- channels of the membrane (Inoue, 1985). The amount of outward rectification depended on the species of anion used and was strongly influenced by temperature and internal pH. In contrast to the anion conductances themselves, the conductance relative to Cl- (gA/gCl) was found to be quite stable against changes in the membrane potential, temperature, and pH. It is therefore suggested that each gA/gCl is an intrinsic quantity of the Cl- channel of the squid axon membrane. The sequence and values of gA/gCl obtained in this study were NO3- (1.80) greater than I- (1.40) greater than Br- (1.07) greater than Cl- (1.00) greater than MeSO3- (0.46) greater than H2PO2- (0.33) greater than CH3COO- (0.29) greater than SO4(2-) (0.06).

We report the formation of purple hemocyanin upon addition of ethyleneglycol to a solution of Sepioteuthis lessoniana oxyhemocyanin in 0.05 M Tris-HCl buffer (pH 7.5). Spectroscopic studies on the purple hemocyanin indicate that this transformation between the normal blue state and the purple state of oxyhemocyanin is essentially a reversible one. The purple hemocyanin exhibits esr signals that correspond to about one-fifth of the total copper obtained. The results suggest that ethyleneglycol causes a moderate and reversible deformation of the active site of the oxyhemocyanin.

Loliginid squids of the Sepioteuthis lessoniana complex are widely spread in the Indo-Pacific Ocean, where they constitute a commercially important resource for neritic fisheries. Sepioteuthis lessoniana is the only Lessepsian squid migrant till now, recorded for the first time in the Mediterranean in 2002 along the Turkish Levantine coasts. Two maturing males, with mantle lengths 193 mm and 244 mm, have been recently caught near the coasts of Rhodes Island (SE Aegean), extending the species distribution northward, into Hellenic waters. Their identity was confirmed by comparison of the main body, beak characteristics and morphometric measurements with those available in the literature for this species. Suspected expansion of the Lessepsian loliginid into the Aegean Sea, due to the gradual warming of the sea, is discussed.

A juvenile male specimen of the tropical corallophilic loliginid squid Sepioteuthis sepioidea (Blainville, 1823) is reported from Woods Hole, Massachusetts. Nearest recorded populations are at Cape Kennedy, Florida, and Bermuda at distances of 1440 and 950 km respectively. From current patterns it is inferred that the specimen was more likely wafted from the former area.

WE have succeeded (through improving the feed during the earlier stages after hatching) in rearing three species of the cuttlefish (Sepia esculenta Hoyle, Sepia subaculeata Sasaki and Sepiella maindroni de Rochebrune) and two species of the squid (Sepioteuthis lessoniana Lesson and Euprymna beryii Sasaki)1. The main points to note in rearing these animals are as follows