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Octopus (Octopus vulgaris, Mollusca, Cephalopoda) is an important and valuable fishery resource on the eastern and southern coasts of Tunisia, but its landings are highly variable. This paper explores the effect of environment on octopus catch per unit effort (CPUE) during a 12‐year period, through correlation analyses and the incorporation into surplus production models of sea surface temperature (SST) and rainfall data collected during cold (January–May) and hot (August–October) seasons. CLIMPROD software was used to select the appropriate model and fit it to the fishery and environment data. In both seasons, SST significantly contributed to CPUE variability; fishery production was influenced positively by cold season SST but negatively by hot season SST. Due to a poor fit with cold season data, the impact of rainfall was analysed only for the hot season, during which it has a positive effect on production. Results are discussed in view of the life‐cycle of octopus and the dynamics of the Tunisian fishery. This first study of octopus variability in Tunisia highlights the necessity to incorporate environmental influence into stock assessment and management advice.  相似文献   
2.
Twenty-seven species of cephalopods are identified from an exposure of the Grayson Formation, Washita Group at the Waco Dam Spillway, McLennan County, north-central Texas. Mariella (Mariella) camachoensis (Böse), (?)Stomohamites sp., Engonoceras serpentinum (Cragin), Puzosia cf. crebrisulcata Kossmat, Mantelliceras cf. cantianum Spath, Mantelliceras saxbii (Sharpe), Sharpeiceras mexicanum (Böse), (?)Paracalycoceras sp., and Neohibolites sp. are reported from the Grayson Formation for the first time. The occurrence of Mantelliceras cf. cantianum, Mantelliceras saxbii, Sharpeiceras mexicanum, and (?)Paracalycoceras sp. indicates an early Cenomanian age for the Grayson exposed at the Waco Spillway locality. Previously, these mantellicerid ammonites have been recorded from the Buda Limestone interval which overlies the Grayson in north-central Texas.  相似文献   
3.
An ammonite fauna from the upper Abderaz Formation of Kuh-e-Bul in the northwestern part of the Koppeh Dagh (Iran) is described and illustrated. The collection of 30 specimens is assigned to seven species, all of which are recorded from Iran for the first time: Pseudophyllites indra (Forbes, 1846), Pachydiscus (Pach.) haldemsis (Schlüter, 1867), Patagiosites stobaei (Nilsson, 1827), Menuites wittekindi (Schlüter, 1876), Glyptoxoceras retrorsum (Schlüter, 1872), Lewyites elegans (Moberg, 1885) and Trachyscaphites spiniger (Schlüter, 1872). This fauna is of a typical Boreal character, with all taxa having been described from northwest Europe originally. The stratigraphic range indicated by the ammonites is lower upper Campanian, below the first occurrence of Nostoceras (Bostrychoceras) polyplocum (Roemer, 1841) and probably above the last occurrence of Hoplitoplacenticeras (H.) vari (Schlüter, 1872). A nannofossil sample from the ammonite-bearing interval corresponds to the upper Campanian nannofossil zone UC15/CC22. Thus, on the basis of both ammonites and calcareous nannofossils, the upper Abderaz Formation is shown to be younger than assumed previously.  相似文献   
4.
The position of the Cenomanian-Turonian boundary is established for the first time in Charente-Maritime, northwestern Aquitaine (France), on the basis of ammonite occurrences and the δ13C isotope curve, corresponding to Oceanic Anoxic Event 2, that straddles the boundary. The earliest Turonian ammonites recognised are a monospecific occurrence of the early early Turonian pseudotissotiine Bageites bakui Zaborski, 1998, previously known only from northern Nigeria. Newly collected material and well-preserved specimens from existing collections supplement previous records, and include species of Placenticeras, Morrowites, Kamerunoceras, Romaniceras (Romaniceras), Spathites (Jeanrogericeras), Mammites, Fagesia, Neoptychites, Choffaticeras (Leoniceras), Collignoniceras and Lecointriceras. These confirm the presence of the upper lower Turonian nodosoides Zone and the lower middle Turonian turoniense and kallesi zones/subzones of authors.  相似文献   
5.
Long-finned pilot whales (Globicephala melas), Risso's dolphins (Grampus griseus), melon-headed whales (Peponocephala electra), Cuvier's beaked whales (Ziphius cavirostris), Sowerby's beaked whales (Mesoplodon bidens), northern bottlenose whales (Hyperoodon ampullatus), sperm whales (Physeter macrocephalus), dwarf sperm whales (Kogia sima) and pygmy sperm whales (Kogia breviceps) make up the large community of deep-diving odontocetes occurring off the Bay of Biscay, northeast Atlantic. The ecology of these toothed cetaceans is poorly documented worldwide. The present study described their prey preferences from stomach content analysis and showed resource partitioning within the assemblage. The majority of the species appeared to be mostly teutophageous. Fish was an important food source only for the Sowerby's beaked whale and, to a lesser extent, for the long-finned pilot whale. In terms of foraging habitats inferred from prey composition, either pelagic oceanic or demersal neritic habitats were exploited by toothed whales in the Bay of Biscay, with only the long-finned pilot whale foraging in the two habitats. Finally, with more than 14,000 identified cephalopods from 39 species, the present study highlighted also the poorly known deep-sea cephalopod community off the Bay of Biscay using top predators as biological samplers.  相似文献   
6.
Coiled nautiloid cephalopods from the British Silurian are described and their taxonomy revised. The Order Oncocerida is represented by a single specimen of Oxygonioceras oxynotum. Twelve species from the Order Tarphycerida (within which is here subsumed the Order Barrandeocerida) are described: one of Trocholites, two of Ophioceras, two of Catyrephoceras, three of Lechitrochoceras, one of Peismoceras, two of Systrophoceras, and one of Uranoceras. Their distribution, stratigraphical and geographical, is indicated.  相似文献   
7.
中国经济头足类增养殖现状及展望   总被引:1,自引:1,他引:0  
头足类(Cephalopods)是软体动物门的重要组成部分,在中国海洋渔业中占有重要的经济地位。开展头足类增养殖,对于保护中国种质资源、提高头足类产量具有重要意义。本文就目前中国主要的经济头足类,包括金乌贼(Sepia esculenta)、拟目乌贼(S.lycidas)、虎斑乌贼(S.pharaonis)、无针乌贼(Sepiella japonica)、长蛸(Octopus minor)、真蛸(O.vulgaris)以及短蛸(Amphioctopus fangsiao)的繁殖习性、幼体培育、成体养成等各阶段生活史的研究进展和存在问题进行阐述,并对其发展前景进行展望,旨在为中国头足类养殖产业提供借鉴。  相似文献   
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