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  • 1
    Publication Date: 2022-05-25
    Description: Author Posting. © University of Chicago Press, 2007. This article is posted here by permission of University of Chicago Press for personal use, not for redistribution. The definitive version was published in American Naturalist 169 (2007): 543–551, doi:10.1086/512106.
    Description: Cephalopods are well known for their diverse, quick‐changing camouflage in a wide range of shallow habitats worldwide. However, there is no documentation that cephalopods use their diverse camouflage repertoire at night. We used a remotely operated vehicle equipped with a video camera and a red light to conduct 16 transects on the communal spawning grounds of the giant Australian cuttlefish Sepia apama situated on a temperate rock reef in southern Australia. Cuttlefish ceased sexual signaling and reproductive behavior at dusk and then settled to the bottom and quickly adapted their body patterns to produce camouflage that was tailored to different backgrounds. During the day, only 3% of cuttlefish were camouflaged on the spawning ground, but at night 86% (71 of 83 cuttlefish) were camouflaged in variations of three body pattern types: uniform (n=5), mottled (n=33), or disruptive (n=34) coloration. The implication is that nocturnal visual predators provide the selective pressure for rapid, changeable camouflage patterning tuned to different visual backgrounds at night.
    Description: This work was made possible by grant 7456-03 from the National Geographic Society Committee on Research and Exploration and support from the Sholley Foundation.
    Keywords: Crypsis ; Concealment ; Disruptive coloration ; Coincident disruptive coloration ; Cephalopod ; Sepia apama
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 2
    ISSN: 1432-0878
    Keywords: Statocyst ; Statolith defects ; Cephalopods ; Octopus ; Squid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Individuals of seven species of coleoid cephalopods (three species of octopus, three of squid, and one of cuttlefish), that were cultured and reared in laboratory aquarium systems, had a behavioral defect at hatching which was characterized by an inability to control orientation while swimming. These defective animals were designated as “spinners.” An examination of statocysts from individuals of five of the affected species revealed abnormalities of the neuroepithelial suprastructures: absence or malformation of the statolith of the gravity receptor system and absence of the cupulae of the angular acceleration receptor systems. The sensory epithelia did not differ from those of normal animals, nor did the synaptic structures and relationships, when examined both with scanning and transmission electron microscopy. The abnormalities were compared with congenital defects of the neuropeithelial suprastructures of the vestibular apparatus (especially in mammals). The defects observed in statocysts of spinner animals are thought to be the result of environmental causes, such as the temperature or chemistry of the seawater in the transportation vessels or rearing systems, rather than genetic causes.
    Type of Medium: Electronic Resource
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  • 3
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    Institut de biochimie et de biologie appliquée, Université de Caen
    In:  In: La seiche : actes du Premier Symposium international sur la seiche, Caen, 1-3 juin 1989. Institut de biochimie et de biologie appliquée, Université de Caen, Caen, pp. 313-323. ISBN 2-905461-55-1
    Publication Date: 2020-05-11
    Type: Book chapter , PeerReviewed
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  • 4
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    University of Hawaii Press
    In:  Pacific Science, 41 (1-4). pp. 104-122.
    Publication Date: 2020-06-15
    Description: Octopus digueti Perrier and Rochebrune, 1894 was reared through its life cycle at 25°C in a closed seawater system using artificial sea water. Two field-collected females produced 231 hatchlings: 193 hatchlings were groupcultured while 24 were isolated at hatching and grown individually to allow precise analyses of growth in length and weight over the life cycle. All octopuses were fed primarily live shrimps. Maturing adults fed at a rate of 4.7% of body weight per day and had a gross growth efficiency of 48%. Growth in weight was exponential for the first 72 days and described best by the equation: WW(g) = .0405e•0646t. The mean growth rate over this period was 6.4% increase in body weight per day (%/d), with no significant difference between male and female growth. From 72 to 143 days, growth was logarithmic and described best by the equation: WW(g) = (6.78 x 1O- 6) t3 .13. Females grew slightly faster than males over this growth phase. During the exponential growth phase, mantle length increased at a mean rate of 2.1% per day, declining to 1.1% per day over the logarithmic phase. No attempt was made to describe mathematically the period of declining growth rate beyond day 143. The primary causes of early mortality in group culture were escapes and cannibalism. Survival was good despite high culture density: 73% survival to date of first egg laying (day 111). Survival was better among the isolated growth-study octopuses: 88% to the date of first egg laying (day 130). Mean life span was 199 days in group-reared octopuses and 221 days in the growth-study octopuses. There was no significant difference between male and female life span. Progeny of the group culture were reared at similar stocking densities and fed predominantly fresh dead shrimp and crab meat. This diet resulted in cannibalism, with only 6% survival to first egg laying on day 128. Fecundity in this group was lower. Octopus digueti is a good candidate for laboratory culture and biological experimentation because of its small size, rapid growth, short life span, and good survival in group culture.
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  • 5
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    Canadian Science Publishing
    In:  Canadian Journal of Fisheries and Aquatic Sciences, 58 (5). pp. 845-857.
    Publication Date: 2021-07-02
    Description: Growth modeling in squid has been hampered by a paucity of raw growth data on live individuals. We reared wild juvenile squid Loligo pealeii, for up to 97 days post capture, to determine the form of growth and to test the hypothesis that a 5°C difference in temperature would significantly affect growth rates. Precapture growth rates (the instantaneous relative growth rate or percent increase in body mass per day (IRGR)) of 8-11% were estimated using statolith age data. Laboratory growth rates over a maximum of 97 experimental days fell into two phases in which most L. pealeii grew exponentially, albeit at a slower rate in phase 2. In both phases, the values of IRGR were significantly higher for L. pealeii reared at 20°C than for those reared at 15°C, being respectively, 4.36 and 2.69 in phase 1 and 2.57 and 1.63 in phase 2. This study provides strong evidence of phase-specific temperature sensitivity in squid growth. The IRGR values obtained were used to simulate the growth of squid hatched in nature from May to September in a simple predictive model. The growth simulations indicated that, by the end of phase-1 growth, squid hatched in June and July were two and three times the weight, respectively, at the same age, as squid hatched in May, owing to their exposure to warmer temperatures.
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  • 6
    Publication Date: 2021-08-23
    Description: Fatty acid and stable isotope analyses have previously been used to investigate foraging patterns of fish, birds, marine mammals and most recently cephalopod species. To evaluate the application of these methods for dietary studies in squid, it is important to understand the degree to which fatty acid and stable isotope signatures of prey species are reflected in the squids' tissue. Four groups of Lolliguncula brevis were fed on prey species with distinctly different fatty acid and stable isotope profiles over 30 consecutive days. One group of squid were fed fish for fifteen days, followed by crustaceans for a further fifteen days. A second and third group were fed exclusively on fish or crustaceans for thirty days. And a fourth group was fed on a mixture of fish and crustaceans for thirty days. Analysis of squid tissue showed that, after 10 days of feeding, fatty acid profiles of squid tended to reflect those of their prey. Squid that fed on a single prey type, i.e. fish or crustacean, showed only minor modifications in fatty acid proportions after the initial change and fatty acid profiles were clearly distinguishable between the two feeding groups. Shifts in fatty acid proportions towards respective prey profiles could clearly be observed in squid the diet of which was swapped after 15 days. Clear differences could also be seen in fatty acid profiles of squid feeding on a mixed diet with trends towards either fish or crustacean fatty acid signatures. Stable isotope signatures of squid tissues clearly distinguished between animals feeding on different diets and supported findings from fatty acid analysis, thus indicating both methods to be viable tools in feeding studies on squid species.
    Type: Article , PeerReviewed
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