Ecology and growth of juvenile California spiny lobster, Panulirus interruptus (Randall)

ABSTRACT TRANSCRIBED FROM ENGLE'S PH.D. ORAL DEFENSE PAMPHLET: The natural history of juvenile California spiny lobster, Panulirus interruptus (Randall), was investigated, with primary emphasis placed on ascertaining juvenile habitats, determining juvenile growth rates and component growth processes, and evaluating ecological and behavioral phenomena associated with juvenile survival and growth. Habitat surveys of island and mainland localities throughout southern and lower California revealed that small, greenish juveniles typically inhabit crevices or temporary burrows in 0-4m deep, wave-swept rocky habitats covered by dense beds of surf grass, Phyllospadix torreyi S. Watson. Phyllospadix beds were more abundant on gradually sloping rocky mainland beaches than on steeply sloping island shores. Phyllospadix abundance was positively correlated with P. interruptus abundance; however, at Santa Catalina Island, the Phyllospadix habitat was not extensive enough to be the sole lobster nursery. In laboratory tests, puerulus larvae and early juveniles chose Phyllospadix over rubble rocks or broad-bladed kelp, but did not consistently prefer Phyllospadix over reticulate algae. Ecology, growth, and behavior of juvenile P. interruptus inhabiting a discrete Phyllospadix habitat at Bird Rock, Santa Catalina Island, were investigated from October 1974 through December 1976 by means of frequent scuba surveys. Pueruli settled from June to November. Peak recruitment occurred from July to September, when seasonal temperatures were maximal. Settled larvae were approximately one year old. Juvenile growth was determined by size-frequency, single molt increment, mark-recapture, and laboratory culture studies. Carapace length vs. wet weight relationships fit standard power curve equations. Bird Rock juveniles grew from 7 to 32mm CL in 10-11 molts and from 32 to 56mm CL in 5-6 molts during their first and second benthic years, respectively. Growth rates were similar for males and females. Juveniles regenerating more than two limbs grew less per molt than intact lobsters. Long-term growth of laboratory-reared juveniles was 20% less than that of field lobsters. Growth component multiple regression analyses demonstrated that molt increment was directly proportional to premolt size and temperature for age 1+ lobsters. Molt frequency was inversely proportional to size and directly proportional to temperature. Temperature affected age 2+ lobsters similarly, but molt increment was independent of size, and molt frequency declined at a different rate. Juvenile growth rates more than doubled during warm water months compared to cold water months, primarily because of increased molt frequency. Based on results from this study and from previous investigations, it is estimated that P. interruptus males and females become sexually mature by ages 4 and 5 years, respectively, and that legai size is reached by 7 or 8 years of age. Juvenile P. interruptus activity patterns and foraging behavior were similar to those of adults, except that juvenile home ranges were proportionally smaller, and small juveniles were apparently not attracted to distant food. Small mollusks, abundant in Phyllospadix habitats, were the major food items. Size-dependent predation by fish and octopus apparently caused the considerable juvenile mortality observed at Bird Rock. Juveniles approaching 2 years of age gathered in mixed size-class aggregations by day and foraged beyond the grass beds at night. In autumn, these juveniles migrated to deeper habitats, coincident with new puerulus settlement in the Phyllospadix beds. Based on strong inferences from the results, it is proposed that size-dependent predation is the most important factor determining the !ife history strategy of juvenile P. interruptus. Life history tactics promoting rapid growth apparently function dually in reducing the period of high vulnerability to predation and decreasing the time required to reach sexual maturity. The Phyllospadix habitat is an excellent lobster nursery because it provides shelter from predators and possesses abundant food resources for sustaining optimum juvenile growth rates in shallow, warm water.

The food habits of four kelp-bed rockfishes (Scorpaenidae, Sebastes) off Santa Barbara, California

The diets of four common rockfishes from the kelp beds near Santa Barbara, California, were determined by gut contents analysis, and related to feeding strategies. The guts of one hundred specimens of each species were examined, and the importance of prey evaluated by their frequency of occurrence, numbers, and volumes. The volumes of stomach contents were standardized for the size of specimen. Estimates of overlap in diet between the species were made. Sebastes atrovirens fed primarily on small animals from the kelp canopy, and may have employed a browsing rather than pursuing strategy of feeding. It showed low overlap in diet with the three bottom-dwelling species, S. carnatus, S. chrysomelas, and S. vexillaris, all of which preferred larger types of prey and seemed more like pursuers. The closely related S. carnatus and S. chrysomelas were quite similar in diet, eating primarily medium sized demersal invertebrates, especially crabs and shrimp. S. vexillaris ate fewer crabs and shrimp but more large-sized fish and octopus than the latter two species. Its more active life style indicates that it may react to prey at greater distances and have a larger home range than these species, as has been predicted for pursuers feeding on larger (and rarer) prey.

Studies on mollusca of Saurashtra coast - 3. Composition

The paper presents the seasonal variations in moisture, protein, salt and ash in the meat of Murex virgineus, Solen sp., Loligo sp., Sepiella inermis and Octopus sp. Moisture and fat contents of twenty two species of molluscs are reported. Inverse relationship between protein and ash has been observed. Cephalopoda recorded higher meat, moisture and protein contents than amphineura, gastropoda and pelecypoda. Pelecypoda contains higher fat than amphineura, gastropoda and cephalopoda.

Pink Worlds and Blue Worlds: A Portrait of Intimate Polarity

Griffiths, Merris, 'Pink Worlds and Blue Worlds: A Portrait of Intimate Polarity', In: 'Small Screens: television for children', D. Buckingham (Ed.), (London: Leicester University Press), pp. 159-184, 2002 RAE2008

Habitat and distribution of the warm-water barnacle Solidobalanus fallax (Crustacea: Cirripedia)

New records are given of the occurrence of the warm-water barnacle Solidobalanus fallax in Britain and Europe. This barnacle is not found on rocks or stones, but settles on biological substrata, including algae, cnidarians, bivalves, gastropods and crustaceans. It also settles on plastic bags and nets, plastic-coated objects such as crab and lobster pots and octopus pots made of ceramic or plastic. With one exception the species was unrecorded in Europe before 1980; it may have increased in abundance during recent years as a result of rising temperatures. The cyprid larvae, which can metamorphose on plastic Petri dishes, appear to be adapted to seek out ‘low energy’ surfaces. One of the habitats colonized by S. fallax is the sea-fan Eunicella verrucosa, where it seems to have increased in recent years, possibly to the detriment of the cnidarian host. Solidobalanus fallax has the potential to be a serious pest of fish-farming structures to the south of Britain

THE INFORMATION ERA THREATENS PRIVACY: A Comparative Study of Electronic Money’s Privacy Policies and Privacy Laws

This thesis consists of an analysis of electronic money (e-money), e-money’s privacy policies and relevant privacy laws. The value of information and the development of technology enhance the risk of privacy violations in the information era. Consumer privacy interests with respect to e-money are governed in part by the Personal Information Protection and Electronic Documents Act (PIPEDA) in Canada and by the European Union’s Data Protection Directive. The analysis is directed at whether the privacy policies of three kinds of e-money – Octopus Card, PayPal and MasterCard – comply with the spirit and letter of these laws. In light of technology change, the laws should be interpreted to apply broadly to protect privacy interests. Enhanced privacy protection may in fact lead to greater adoption of e-money by consumers.

Distribution, extent of inter-annual variability and diet of the bloom-forming jellyfish Rhizostoma in European waters

Jellyfish (Cnidaria: Scyphozoa) are increasingly thought to play a number of important ecosystem roles, but often fundamental knowledge of their distribution, seasonality and inter-annual variability is lacking. Bloom forming species, due to their high densities, can have particularly intense trophic and socio-economic impacts. In northern Europe it is known that one particularly large (up to 30 kg wet weight) bloom forming jellyfish is Rhizostoma spp. Given the potential importance, we set out to review all known records from peer-reviewed and broader public literature of the jellyfish R. octopus (Linnaeus) and R. pulmo (Macri) (Scyphozoa: Rhizostomae) across western Europe. These data revealed distinct hotspots where regular Rhizostoma spp. aggregations appeared to form, with other sites characterized by occasional abundances and a widespread distribution of infrequent observations. Surveys of known R. octopus hotspots around the Irish Sea also revealed marked inter-annual variation with particularly high abundances forming during 2003. The location of such consistent aggregations and inter-annual variances are discussed in relation to physical, climatic and dietary variations.

Stranding events provide indirect insights into the seasonality and persistence of jellyfish medusae (Cnidaria : Scyphozoa)

It is becoming increasingly evident that jellyfish (Cnidaria: Scyphozoa) play an important role within marine ecosystems, yet our knowledge of their seasonality and reproductive strategies is far from complete. Here, we explore a number of life history hypotheses for three common, yet poorly understood scyphozoan jellyfish (Rhizostoma octopus; Chrysaora hysoscella; Cyanea capillata) found throughout the Irish and Celtic Seas. Specifically, we tested whether (1) the bell diameter/wet weight of stranded medusae increased over time in a manner that suggested a single synchronised reproductive cohort; or (2) whether the range of sizes/weights remained broad throughout the stranding period suggesting the protracted release of ephyrae over many months. Stranding data were collected at five sites between 2003 and 2006 (n = 431 surveys; n = 2401 jellyfish). The relationship between bell diameter and wet weight was determined for each species (using fresh specimens collected at sea) so that estimates of wet weight could also be made for stranded individuals. For each species, the broad size and weight ranges of stranded jellyfish implied that the release of ephyrae may be protracted (albeit to different extents) in each species, with individuals of all sizes present in the water column during the summer months. For R. octopus, there was a general increase in both mean bell diameter and wet weight from January through to June which was driven by an increase in the variance and overall range of both variables during the summer. Lastly, we provide further evidence that rhizostome jellyfish may over-wintering as pelagic medusa which we hypothesise may enable them to capitalise on prey available earlier in the year.

The energy density of jellyfish: Estimates from bomb-calorimetry and proximate-composition

Two techniques are described to calculate energy densities for the bell, gonad and oral arm tissues of three scyphozoan jellyfish (Cyanea capillata, Rhizostoma octopus and Chrysaora hysoscella). First, bomb-calorimetry was used, a technique that is readily available and inexpensive. However, the reliability of this technique for gelatinous material is contentious. Second, further analysis involving the more labour intensive proximate-composition analysis (protein, fat and carbohydrate) was carried out on two species (C capillata and R. octopus). These proximate data were subsequently converted to energy densities. The two techniques (bomb-calorimetry and proximate-composition) gave very similar estimates of energy density. Differences in energy density were found both amongst different species and between different tissues of the same species. Mean ( +/- S.D.) energy density estimates for whole animals from bomb-calorimetry were 0.18 +/- 0.05, 0.11 +/- 0.04, and 0.10 +/- 0.03 kJ g wet mass(-1) for C. capillata, R. octopus, and C. hysoscella respectively. The implications of these low energy densities for species feeding on jellyfish are discussed. (c) 2007 Elsevier B.V. All rights reserved.

The ocean sunfish Mola mola: insights into distribution, abundance and behaviour in the Irish and Celtic Seas

Here we provide baseline data on the distribution and abundance of Mola mola within the Irish and Celtic Seas, made during aerial surveys from June to October during 2003-2005. These data were considered in conjunction with concurrent observations of three potential jellyfish prey species found throughout the region: Rhizostoma octopus, Chrysaora hysoscella and Cyanea capillata. A total area of 7850 km(2) was surveyed over the three years with an observed abundance of 68 sunfish giving a density of 0.98 ind/100 km(2). Although modest, these findings highlight that the species is more common than once thought around Britain and Ireland and an order of magnitude greater than the other apex jellyfish predator found in the region, the leatherback turtle (Dermochelys coriacea). furthermore, the distribution of sunfish sightings was inconsistent with the extensive aggregations of Rhizostoma octopus found throughout the study area. The modelled distributions of predator-prey co-occurrence (using data for all three jellyfish species) was less than the observed co-occurrence with the implication that neither jellyfish nor sunfish were randomly distributed but co-occurred more in the same areas than expected by chance. Finally, observed sunfish were typically small (similar to 1 in or less) and seen to either bask or actively swim at the surface.

Jellyfish aggregations and leatherback turtle foraging patterns in a temperate coastal environment

Leatherback turtles (Dermochelys coriacea) are obligate predators of gelatinous zooplankton. However, the spatial relationship between predator and prey remains poorly understood beyond sporadic and localized reports. To examine how jellyfish (Phylum Cnidaria: Orders Semaeostomeae and Rhizostomeae) might drive the broad-scale distribution of this wide ranging species, we employed aerial surveys to map jellyfish throughout a temperate coastal shelf area bordering the northeast Atlantic. Previously unknown, consistent aggregations of Rhizostoma octopus extending over tens of square kilometers were identified in distinct coastal

Developing a simple, rapid method for identifying and monitoring jellyfish aggregations from the air

Within the marine environment, aerial surveys have historically centred on apex predators, such as pinnipeds, cetaceans and sea birds. However, it is becoming increasingly apparent that the utility of this technique may also extend to subsurface species such as pre-spawning fish stocks and aggregations of jellyfish that occur close to the surface. In light of this, we tested the utility of aerial surveys to provide baseline data for 3 poorly understood scyphozoan jellyfish found throughout British and Irish waters: Rhizostoma octopus, Cyanea capillata and Chrysaora hysoscella. Our principal objectives were to develop a simple sampling protocol to identify and quantify surface aggregations, assess their consistency in space and time, and consider the overall applicability of this technique to the study of gelatinous zooplankton. This approach provided a general understanding of range and relative abundance for each target species, with greatest suitability to the study of R. octopus. For this species it was possible to identify and monitor extensive, temporally consistent and previously undocumented aggregations throughout the Irish Sea, an area spanning thousands of square kilometres. This finding has pronounced implications for ecologists and fisheries managers alike and, moreover, draws attention to the broad utility of aerial surveys for the study of gelatinous aggregations beyond the range of conventional ship-based techniques.

Identification of genetically and oceanographically distinct blooms of jellyfish

Reports of nuisance jellyfish blooms have increased worldwide during the last half-century, but the possible causes remain unclear.Apersistent difficulty lies in identifying whether blooms occur owing to local or regional processes. This issue can be resolved, in part, by establishing the geographical scales of connectivity among locations, which may be addressed using genetic analyses and oceanographic modelling. We used landscape genetics and Lagrangian modelling of oceanographic dispersal to explore patterns of connectivity in the scyphozoan jellyfish Rhizostoma octopus, which occurs en masse at locations in the Irish Sea and northeastern Atlantic. We found significant genetic structure distinguishing three populations, with both consistencies and inconsistencies with prevailing physical oceanographic patterns. Our analyses identify locations where blooms occur in apparently geographically isolated populations, locations where blooms may be the source or result of migrants, and a location where blooms do not occur consistently and jellyfish are mostly immigrant. Our interdisciplinary approach thus provides a means to ascertain the geographical origins of jellyfish in outbreaks, which may have wide utility as increased international efforts investigate jellyfish blooms. © 2013 The Authors.

Quantification of interpoint topographic correlations of threshold values in glaucomatous visual fields

Purpose: The authors sought to quantify neighboring and distant interpoint correlations of threshold values within the visual field in patients with glaucoma. Methods: Visual fields of patients with confirmed or suspected glaucoma were analyzed (n = 255). One eye per patient was included. Patients were examined using the 32 program of the Octopus 1-2-3. Linear regression analysis among each of the locations and the rest of the points of the visual field was performed, and the correlation coefficient was calculated. The degree of correlation was categorized as high (r > 0.66), moderate (0.66 = r > 0.33), or low (r = 0.33). The standard error of threshold estimation was calculated. Results: Most locations of the visual field had high and moderate correlations with neighboring points and with distant locations corresponding to the same nerve fiber bundle. Locations of the visual field had low correlations with those of the opposite hemifield, with the exception of locations temporal to the blind spot. The standard error of threshold estimation increased from 0.6 to 0.9 dB with an r reduction of 0.1. Conclusion: Locations of the visual field have highest interpoint correlation with neighboring points and with distant points in areas corresponding to the distribution of the retinal nerve fiber layer. The quantification of interpoint correlations may be useful in the design and interpretation of visual field tests in patients with glaucoma.

Sensitivity and specificity of frequency-doubling technology, tendency-oriented perimetry, and Humphrey Swedish interactive threshold algorithm-fast perimetry in a glaucoma practice

PURPOSE: To evaluate the sensitivity and specificity of the screening mode of the Humphrey-Welch Allyn frequency-doubling technology (FDT), Octopus tendency-oriented perimetry (TOP), and the Humphrey Swedish Interactive Threshold Algorithm (SITA)-fast (HSF) in patients with glaucoma. DESIGN: A comparative consecutive case series. METHODS: This was a prospective study which took place in the glaucoma unit of an academic department of ophthalmology. One eye of 70 consecutive glaucoma patients and 28 age-matched normal subjects was studied. Eyes were examined with the program C-20 of FDT, G1-TOP, and 24-2 HSF in one visit and in random order. The gold standard for glaucoma was presence of a typical glaucomatous optic disk appearance on stereoscopic examination, which was judged by a glaucoma expert. The sensitivity and specificity, positive and negative predictive value, and receiver operating characteristic (ROC) curves of two algorithms for the FDT screening test, two algorithms for TOP, and three algorithms for HSF, as defined before the start of this study, were evaluated. The time required for each test was also analyzed. RESULTS: Values for area under the ROC curve ranged from 82.5%-93.9%. The largest area (93.9%) under the ROC curve was obtained with the FDT criteria, defining abnormality as presence of at least one abnormal location. Mean test time was 1.08 ± 0.28 minutes, 2.31 ± 0.28 minutes, and 4.14 ± 0.57 minutes for the FDT, TOP, and HSF, respectively. The difference in testing time was statistically significant (P <.0001). CONCLUSIONS: The C-20 FDT, G1-TOP, and 24-2 HSF appear to be useful tools to diagnose glaucoma. The test C-20 FDT and G1-TOP take approximately 1/4 and 1/2 of the time taken by 24 to 2 HSF. © 2002 by Elsevier Science Inc. All rights reserved.