给“龙虾”一个正式名分

《餐饮世界》2003年第5期载《“龙虾”也疯狂》一文，开篇说：“老话说：眼睛一眨，母鸡变鸭！原长于南方稻田沟塘河汊、田头地角的“龙虾”（姑且名之），经过数年的奋斗，竟然堂而皇之地举跃到城市的餐桌上，成了现代人趋之若骛的美食！”对于这一美食之名，何必要“姑且名之”，应该用一个恰当的词语加以确定。其实，它早就有名，学名为“克氏螯虾”

Observation on Behavior of Procambarus clarkii and Eriocheir sinensis in Polyculture System

[Objective] This study aimed to observe and explore the behavior of Procambarus clarkii and Eriocheir sinensis in polyculture system. [Method] P. clarkii and E. sinensis with the same weight were used for the experiment in a relatively small polyculture system. The agonistic behavior of P. clarkii and E. sinensis in the first 30 min of the initial encounter and the fighting results were observed and recorded; the approach-avoidance behavior of P. clarkii to bigger E. sinensis in a relatively large space （the ＂Y＂ maze） was observed and recorded. [Result] The re- sults showed that the times of first aggressions and approaches and the total times of active aggressions and approaches of P. clarkii in the initial period of polyculture experiment were all significantly more than E. sinensis （/：＇〈0.05）; after 30 d of poly- culture, P. clarkfi died in 30% of the groups while E. sinensis died in only 10% of the groups, and they coexisted in 60% of the groups. In the experiment of ap- proach-avoidance behavior of P. clarkii to bigger E. sinensis, with the increase of experiment times, the tendency of approach and avoidance of P. clarkii to the con- trol and E. sinensis became control-prefer （P〈0.05） from insignificantly different （P〉 0.05）, which indicated that the recognition ability of P. clarkii for E. sinensis was sig- nificantly improved, and the selection behavior of E. sinensis was obviously inhibited. [Conclusion] Presumably, polyculture of crayfishes and crabs can achieve better effi- ciency when under appropriate habitat conditions.

Technical Standards for Lotus Root-Redswamp Crayfish Integrated Farming

Lotus root-redswamp crayfish integrated farming is a kind of ecologicalgrow mode on the basis of paddy field, which is an innovated mode for agricultural structure adjustment and special agriculture with high efficiency. In order to regulate producing technology of this mode, the essay puts forward some technical require- ments, stressing on cultivar selection, field works, farming technology and product quality, which aims at providing technical support for agricultural production.

Does Procambarus Clarkii （Girard, 1852） Represent a Threat for Estuarine Brackish Ecosystems of Northeastern Adriatic Coast （Italy）？

The ongoing expansion of P. clarkii in the aquatic environments of northern Italy, where it is very common and abundant in most of the streams, lakes and reservoirs, led us to worry about the possibility of invasion into the estuarine and lagoonal brackish environments of the Adriatic coast, which is important not only for their peculiar fauna and flora and high biodiversity, but also for fishing and aquaculture. We carried out laboratory tests to investigate whether this species could live, moult and breed in water with different salinity levels. Several stocks of adult individuals, acclimated before the laboratory experiments, were maintained and monitored daily for a long period （100 days） in glass aquaria with water salinity varying from 5 to 33 ppt. They not only survived during the whole experiment period in levels up to 25 ppt, but also they regularly moulted and mated. These results confirmed that the species could invade the estuarine and brackish environments of the Adriatic coast, with all the implied consequences for the native species of both vertebrates and invertebrates and for human livelihoods.

Preliminary Results of Crayfish Distribution and Diseases in Latvia

A lot of water reservoirs offer good natural conditions for crayfish breeding. Today there are four crayfish species present in Latvia--the European species noble crayfish （Astacus astacus）, narrow-clawed crayfish （Astacus leptodactylus）, the North American signal crayfish （Pacifastacus leniusculus） and spiny-cheek crayfish （Orconectes limosus）. In general, crayfish were found in 258 localities--lakes （175）, rivers and streams （66）, reservoirs, ponds and gravel-pits （17）. A. astacus in Latvia is the dominant crayfish species distributed in all regions. Narrow-clawed crayfish was registered since 1960s. North American signal crayfish was introduced due to its resistance to diseases, but spiny-cheek crayfish arrived from Lithuania waters spontaneously. The main threat for crayfish population is crayfish plague, initiated by mucus Aphanomyces astaci. Astacus astacus was more susceptible species in comparison with Pacifastacus leniusculus and Orconectes limosus. Though the North American signal crayfish and spiny-cheek crayfish were not only resistant, they were the carriers of this disease. The physical habitat alterations, pollution and overfishing are significant during the first year breeding period. Crayfish might serve as bacteria carriers and can cause substantial fish diseases （such as aeromonosis, flavobacteriosis）.

Temperature increase impacts personality traits in aquatic non-native species： Implications for biological invasion under climate change

Climate change, such as elevated temperatures, may facilitate biological invasion. Aquatic animal systems are more vulnerable to biological invasion when the temperature rises. Animal personality also plays an important role in the possibility of successful establishment of invasive species. However, it is still unclear how personality traits of invasive species will respond to global warming. This study focuses on juveniles of red swamp crawfish Procambarus clarkii, an invasive poikilothermic species with wide distribution throughout the world, and explores how slight temperature increases influence three personality traits （ac- tivity, boldness and aggressiveness） ofP. clarkii. For each personality, individual variation is to be presented in condition of the same temperature. Individual personality values can significantly increase with the subtle rising of water temperature. Significant correlations among activity, boldness and aggressiveness are found at any temperature stage, and such relationships are main- tained at a similar level in the face of different temperatures. It is most likely that significant expressions of personality traits may be an ecological compensation strategy to offset increased metabolic costs when faced with small temperature increases. Aggres- sion syndromes are formed due to stable linkages between personality traits, in order to acquire allopatric resources efficiently and establish a new population in this species

Can native species crucian carp Carassius auratus recognizes the introduced red swamp crayfish Procambarus clarkii？

Procambarus clarkii is native to the south-central United States （Louisiana） and northeastern Mexico, and is a highly efficient predator that poses a damager to native species after its introduction or invasion. In its natural habitat, P. clarkii consumes Carassius auratus, however, whether C. auratus recognizes P. clarkii as a predator is not yet clear. In laboratory experiments, we investigated whether experienced and inexperienced C. auratus recognize P. clarkii as a predatory threat and the specific sensory modality used by C. auratus to respond to chemical and visual stimuli from P. clarkii. In the chemical stimuli experiment, two kinds of chemical stimuli were used, water from a tub containing P. clarkii previously fed with C. auratus （C. auratus diet cues） and water from a tub containing unfed P. clarkii （P. clarkii cues）. In the visual experiment, experienced C. auratus decreased activity, but inexperienced C.auratus avoided the predator compartment. When C. auratus diet cues were presented, both experienced and inexperienced C. auratus increased the use of shelter, decreased activity in the initial response phase. Compared with the blank treatment, experienced C. auratus responded to P. clarkii cues by decreasing activity; however, inexperienced C. auratus showed no reduction in activity. C. auratus appears to recognize P. clarkii as a predator both through visual and chemical cues. Further analysis revealed that C. auratus may recognize R clarkii visually through the disturbances caused by P. clarkii movement and chemically by detecting conspecific alarm cues in the diet of P. clarkii. The results also indicate that ex- perienced C. auratus can recognize R clarkii by innate chemical cues from P. clarkii, whereas inexperienced C. auratus cannot [Current Zoology 57 （3）： 330-339, 2011].