Attempted Ambush Predation on Spawning Squids LoligoVulgaris Reynaudii by Benthic Pyjama Sharks, PorodermaAfricanum, off South Africa

1995 ◽  
Vol 75 (3) ◽  
pp. 739-742 ◽  
Author(s):  
Malcolm J. Smale ◽  
Warwick H. H. Sauer ◽  
Roger T. Hanlon
Keyword(s):  
South Africa ◽  
Rocky Reef ◽  
Underwater Video ◽  
Loligo Vulgaris ◽  
Video Recordings ◽  
Behavioural Interactions ◽  
Ambush Predation

This first description of behavioural interactions between benthic pyjama sharks Poroderma africanum (Chondrichthyes: Scyliorhinidae) and spawning squids Loligo vulgaris reynaudii (Cephalopoda: Loliginidae) was made from underwater video recordings. The behaviours are described and illustrated to show that the sharks searched for squids in egg beds, then rested there partially hidden and immobile. The pyjama sharks at-tempted to ambush the squids when they approached to lay their eggs after they had apparently habituated to the predators. Although normally nocturnal, the pyjama sharks had emerged by day from caves and cracks in the rocky reef to attack the spawning squids, thereby benefiting from an occasionally available resource.

СИСТЕМЫ СТАЦИОНАРНОГО ПОДВОДНОГО ВИДЕОНАБЛЮДЕНИЯ ПРИБРЕЖНЫХ АКВАТОРИЙ

2020 ◽  
Author(s):  
V.K. Fishchenko ◽  
P.S. Zimin ◽  
A.V. Zatserkovnyy ◽  
A.E. Subote ◽  
A.V. Golik ◽  
...  
Keyword(s):  
Marine Biology ◽  
Surveillance Systems ◽  
Underwater Video ◽  
Vital Activity ◽  
Geographically Dispersed ◽  
Video Recordings ◽  
Underwater Cameras ◽  
The Pacific ◽  
External Conditions ◽  
Marine Vessels

В Тихоокеанском океанологическом институте (ТОИ) ДВО РАН с 2012 г. ведутся разработки и исследования возможностей технологий стационарного подводного видеонаблюдения. Развернуты три подводныхкомплекса: два в бухте Алексеева (о-в Попова) и один в бухте Витязь (зал. Посьета). К настоящему времени накоплены значительные объемы информации в виде моментальных снимков и видеозаписей подводныхсцен. Разработаны интерфейсы для предоставления этой информации пользователям по каналам сети Интернет. Разработаны технологии поддержки работы территориально разнесенных экспертов, составляющихбиологические описания видеоматериалов, подобных тем, которые разрабатываются в ведущих зарубежныхорганизациях по морской биологии. Разработаны и апробированы методики оценивания по видеоинформации параметров жизнедеятельности некоторых видов морских гидробионтов. Благодаря непрерывностинаблюдения зафиксировано нескольких редких случаев, представляющих интерес для морских биологов. Разработаны и апробированы методики оценивания гидрологических характеристик среды на основе анализавидеотрансляций с подводных камер. Эти результаты представляются важными в контексте сопровождениянаблюдений за жизнедеятельностью морской биоты данными о внешних условиях, в которых она происходит. Продемонстрирована возможность использования звукового канала камер для регистрации и анализаакустических шумов от морских судов. Продемонстрирована возможность применения подводных видеокомплексов для организации экспериментов по изучению реакции морских гидробионтов на воздействие целенаправленных физических сигналов.Since 2012, the Pacific Oceanological Institute of FarEastern Branch of the Russian Academy of Science has beendeveloping and studying the capabilities of technologies ofstationary underwater video surveillance. Three of the underwatercomplexes have been deployed in different waterareas: two in the Alekseev Bay (Popova Island) and one inVityaz Bay (Posyet Gulf). At this point, complexes have accumulateda significant amount of data in the form of snapshotsand video recordings of underwater scenes, which canbe accessed through designed Internet-based interfaces. Allthe surveillance systems contain technologies as a support ofthe work of geographically dispersed experts involved in thebiological description of video materials, similar to ones developedin leading worldwide marine biology organizations.Besides, the estimation of vital parameters of some marinelife species by the video recordings can be performed usingdeveloped and tested methods. Thanks to continuous observation,the designed systems have already recorded severalrare cases of interest for marine biologists. Hydrologicalcharacteristics of surrounding media can be studied usingdeveloped and tested methods of analysis of video streamingfrom underwater cameras. These results are especially crucialfor accompanying observations of the vital activity ofmarine organisms with data on external conditions in whichthey occur. Cameras built-in audio channels can be used forrecording and analyzing noises of marine vessels. Designedunderwater video complexes provide an opportunity forconducting experiments on studying the reaction of marineorganisms to dedicated physical signals.

scholarly journals Bottom temperature and in situ development of chokka squid eggs (Loligo vulgaris reynaudii) on mid-shelf spawning grounds, South Africa

2009 ◽  
Vol 66 (9) ◽  
pp. 1967-1971 ◽  
Author(s):  
Anè Oosthuizen ◽  
Mike J. Roberts
Keyword(s):  
South Africa ◽  
Bottom Temperature ◽  
Egg Development ◽  
Spawning Grounds ◽  
Loligo Vulgaris ◽  
Laboratory Results ◽  
Temperature Environment ◽  
Development Data ◽  
Shelf Temperature

Abstract Oosthuizen, A., and Roberts, M. J. 2009. Bottom temperature and in situ development of chokka squid eggs (Loligo vulgaris reynaudii) on mid-shelf spawning grounds, South Africa. – ICES Journal of Marine Science, 66: 1967–1971. The aim of the study was to test the development success of squid eggs on the mid-shelf (60–150 m deep) spawning grounds in relation to previous laboratory results, and to describe the mid-shelf temperature environment and how it could affect egg development. A series of in situ egg incubation experiments was conducted on the mid-shelf (∼119 m deep) spawning grounds using cages, temperature sensors, and acoustic releases for retrieval. Newly spawned eggs were collected by scuba, and continuous temperature data were collected at two points between the known inshore spawning grounds and the mid-shelf areas. Temperature variations followed a seasonal warming and cooling cycle, with superimposed peaks and troughs. Egg development data indicated that warm temperature peaks (10–13°C) are sufficient for normal development of eggs on the mid-shelf. Egg development time on the mid-shelf was 2–3 times longer (50–60 vs. 20–30 d) than inshore. The scarcity of abnormalities (0.45%) disputes previous laboratory results that suggested that ∼50% of eggs would suffer abnormalities in the colder mid-shelf temperature environment.

Fecundity of the chokka squid Loligo vulgaris reynaudii on the southeastern coast of South Africa

1999 ◽  
Vol 135 (2) ◽  
pp. 315-319 ◽  
Author(s):  
W. H. H. Sauer ◽  
Y. C. Melo ◽  
W. de Wet
Keyword(s):  
South Africa ◽  
Southeastern Coast ◽  
Loligo Vulgaris

scholarly journals Sequential Analysis of Livestock Herding Dog and Sheep Interactions

Animals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 352
Author(s):  
Jonathan Early ◽  
Jessica Aalders ◽  
Elizabeth Arnott ◽  
Claire Wade ◽  
Paul McGreevy
Keyword(s):  
Sequential Analysis ◽  
Empirical Studies ◽  
Trial Duration ◽  
Video Recordings ◽  
Efficient Performance ◽  
Competition Level ◽  
Chi Squared ◽  
Behavioural Interactions ◽  
Log Linear ◽  
Event Based

Livestock herding dogs are crucial contributors to Australian agriculture. However, there is a dearth of empirical studies of the behavioural interactions between dog and livestock during herding. A statistical approach that may reveal cause and effect in such interactions is lag sequential analysis. Using 48 video recordings of livestock herding dogs and sheep in a yard trial competition, event-based (time between behaviours is irrelevant) and time-based (time between behaviours is defined) lag sequential analyses identified several significant behavioural interactions (adjusted residuals greater than 2.58; the maximum likelihood-ratio chi-squared statistic for all eight contingency tables identified all sequences as highly significant (p < 0.001)). These sequences were: The dog ceasing all movement followed by the sheep also ceasing movement; the dog chasing the sheep and a group of sheep escaping the main flock; a single sheep escaping the flock and the dog chasing; sheep initiating movement followed by the dog following; foot-stamping followed by the dog ceasing all movement; and, foot-stamping by the sheep and the dog lip-licking in response. Log linear regression identified significant relationships among undesirable behaviours in sheep and both observed trial duration (p = 0.001) and trial score (p = 0.009). No differences in the herding styles of dogs were identified between sex of dog and frequency of sheep escape behaviours (p = 0.355) nor the sex of dog and competition level (p = 0.116). The identification of trial score as a predictor of efficient performance confirms the benefits of incorporating extant objective measures to assess livestock herding dogs.

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