Graded behavioral responses and habituation to sound in the common cuttlefish, Sepia officinalis
Samson, J.E. ; Mooney, T.A. ; Gussekloo, S.W.S. ; Hanlon, R.T. - \ 2014
Journal of Experimental Biology 217 (2014)24. - ISSN 0022-0949 - p. 4347 - 4355.
equal-loudness contours - acoustic startle - water movements - squid - cephalopods - fish - predators - sensitization - lolliguncula - sensitivity
Sound is a widely available and vital cue in aquatic environments yet most bioacoustic research has focused on marine vertebrates, leaving sound detection in invertebrates poorly understood. Cephalopods are an ecologically key taxon that likely use sound and may be impacted by increasing anthropogenic ocean noise, but little is known regarding their behavioral responses or adaptations to sound stimuli. These experiments identify the acoustic range and levels that elicit a wide range of secondary defense behaviors such as inking, jetting, and rapid coloration change. Secondarily, it was found that cuttlefish habituate to certain sound stimuli. The present study examined the behavioral responses of 22 cuttlefish (Sepia officinalis) to pure-tone pips ranging from 80-1000 Hz with sound pressure levels of 85–188 dB re 1 µPa rms and particle accelerations of 0-17.1 m.s-2. Cuttlefish escape responses (inking, jetting) were observed between frequencies of 80-300 Hz and at sound levels above 140 dB re 1 µPa rms and 0.01 m.s-2 (0.74 m.s-2 for inking responses). Body patterning changes and fin movements were observed at all frequencies and sound levels. Response intensity was dependent upon stimulus amplitude and frequency, suggesting that cuttlefish also possess loudness perception with a maximum sensitivity around 150 Hz. Cuttlefish habituated to repeated 200 Hz tone pips, at two sound intensities. Total response inhibition was not reached, however, and a basal response remained present in most animals. The graded responses provide a loudness sensitivity curve and suggest an ecological function for sound-use in cephalopods.
Benefits and organization of cooperative research for fisheries management
Johnson, T.R. ; Densen, W.L.T. van - \ 2007
ICES Journal of Marine Science 64 (2007)4. - ISSN 1054-3139 - p. 834 - 840.
illex-illecebrosus - falkland islands - mortality - atlantic - stocks - squid - cod
Drawing on research in the northeastern USA and northwestern Europe, a description is given of how cooperative research is organized and a statement made of how involving fishers in research can contribute to better fisheries management. The focus is on improving stock assessments through the collection of better fishery-dependent and -independent data and through efforts to address bycatch through gear-selectivity studies. Direct benefits of cooperative research include increased quantity and quality of data, inclusion of fishers' knowledge in science and management, improved relevance of research to fisheries management, and reduced costs of science. Indirect benefits are the buy-in of science and management by industry and improved relationships and trust between fishers and scientists (and managers). These indirect benefits are best achieved under conditions of transparency and communication. In some cases, cooperative research also provides income to the industry and supports the maintenance of fishing infrastructure. Most important, cooperative research improves capacity-building and establishes intellectual property rights within the fishing industry, and it encourages innovative approaches to management, such as adaptive and ecosystem-based approaches. Finally, guidelines for making cooperative research more effective are outlined
Evidence for an elastic projection mechanism in the chameleon tongue
Groot, J.H. de; Leeuwen, J.L. van - \ 2004
Proceedings of the Royal Society. B: Biological Sciences 271 (2004)1540. - ISSN 0962-8452 - p. 761 - 770.
muscle - design - kinematics - tentacles - system - squid
To capture prey, chameleons ballistically project their tongues as far as 1.5 body lengths with accelerations of up to 500 m s-2. At the core of a chameleon's tongue is a cylindrical tongue skeleton surrounded by the accelerator muscle. Previously, the cylindrical accelerator muscle was assumed to power tongue projection directly during the actual fast projection of the tongue. However, high-speed recordings of Chamaeleo melleri and C. pardalis reveal that peak powers of 3000 W kg-1 are necessary to generate the observed accelerations, which exceed the accelerator muscle's capacity by at least five- to 10-fold. Extrinsic structures might power projection via the tongue skeleton. High-speed fluoroscopy suggests that they contribute less than 10% of the required peak instantaneous power. Thus, the projection power must be generated predominantly within the tongue, and an energy-storage-and-release mechanism must be at work. The key structure in the projection mechanism is probably a cylindrical connective-tissue layer, which surrounds the entoglossal process and was previously suggested to act as lubricating tissue. This tissue layer comprises at least 10 sheaths that envelop the entoglossal process. The outer portion connects anteriorly to the accelerator muscle and the inner portion to the retractor structures. The sheaths contain helical arrays of collagen fibres. Prior to projection, the sheaths are longitudinally loaded by the combined radial contraction and hydrostatic lengthening of the accelerator muscle, at an estimated mean power of 144 W kg-1 in C. melleri. Tongue projection is triggered as the accelerator muscle and the loaded portions of the sheaths start to slide over the tip of the entoglossal process. The springs relax radially while pushing off the rounded tip of the entoglossal process, making the elastic energy stored in the helical fibres available for a simultaneous forward acceleration of the tongue pad, accelerator muscle and retractor structures. The energy release continues as the multilayered spring slides over the tip of the smooth and lubricated entoglossal process. This sliding-spring theory predicts that the sheaths deliver most of the instantaneous power required for tongue projection. The release power of the sliding tubular springs exceeds the work rate of the accelerator muscle by at least a factor of 10 because the elastic-energy release occurs much faster than the loading process. Thus, we have identified a unique catapult mechanism that is very different from standard engineering designs. Our morphological and kinematic observations, as well as the available literature data, are consistent with the proposed mechanism of tongue projection, although experimental tests of the sheath strain and the lubrication of the entoglossal process are currently beyond our technical scope.