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1.
Abstract. The production of the hymenosomatid crab Elamenopsis kempi was calculated for a period of 18 months from a subtidal area of the Garmat-Ali river, southern Iraq. The highest average individual somatic energy was attained in spring. Maximum population biomass and production were attained by the summer cohort and the minimum values were exhibited by the overwintering cohort. The fluctuations of the average population biomass were followed throughout the sampling period. Average total annual population production was 13.2 g DW · m-2· a-1 and the P/B ratio was 5.9. These values were compared with those of the most common crustaceans in the region.  相似文献   
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Abstract. The population biology of the portunid crab Liocarcinus arcuatus is analyzed over a yearly cycle in beach zones and mussel raft culture areas in the Ria de Arousa.
The breeding cycle of this species has two annual peaks, which result in two annual cohorts that are recruited in different areas. The growth rate is higher in the group settled in spring than in autumn, and, especially, in the culture areas compared with the beach zones. There are movements from the beach zones to the raft polygons related to reproductive and feeding behavior as well as growth. The role of mussel culture in the dynamics of this species is discussed.  相似文献   
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INTRODUCTIONRaninoidesfoundbyH .MilneEdwards,1 83 7,nowincludessixspeciesinIndo PacificOceans:R .personatusHenderson ,1 888,R .seratifronsHenderson,1 888,R .hendersoniChopra,1 93 1 ,R .barnardiiSakai,1 974 ,R .crosnieriRibes,1 989andR .intermediusDaietXu,1 993 .RecentlyreportedR .perso…  相似文献   
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A new species, Crustorhabditis chitwoodi, was discovered in nutrient agar plates inoculated with beach sand collected from an ocean beach in New South Wales, Australia. The three other known species of the genus have all been found as commensal inhabitants of ocypodid shore crabs. It is suggested that the sand inoculum was seeded with dauer larvae of the nematode that had been dispersed by scavenging crabs. The new species is distinguished from the three previously described species by possessing a smaller number of differently arranged bursal papillae, eight rather than 10. The species is amphimictic, oviparous, and produces abundant dauer larvae in culture, which can be sustained indefinitely on sea water nutrient agar in which it feeds on associated bacteria.  相似文献   
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Variation in a fragment of the mitochondrial control region was investigated to assess the population history of the mangrove land crab, Ucides cordatus L., based on 100 individuals from five locations throughout the Brazilian coast. There was considerable variability in the studied fragment, with every individual showing a distinct haplotype. When regions of ambiguous alignment were removed, 90 haplotypes were still recognized, of which only 1 was shared among locations. There was no statistically significant evidence for geographical structure in the pattern of genetic variability based on a nested clade analysis, even though the geographical distances among the farthest collection sites exceeded 3000 km. Moreover, the mismatch distribution of pairwise differences showed a smooth unimodal distribution that is consistent with a recent population expansion of U. cordatus, either when each location was analysed in isolation or when all samples were combined. Interestingly, the estimates for the duration of such expansion vary latitudinally, suggesting that the expansion of the population of U. cordatus proceeded in a southward direction. These results indicate a possible relationship between the growth in the population of the mangrove land crab and the dynamics of mangrove ecosystems during the Quaternary.  相似文献   
7.
Direct measurements of coastal currents around southern New Zealand   总被引:2,自引:2,他引:0  
Results are presented from direct measurements of subsurface currents at ten coastal positions around the southern half of New Zealand, and from geomagnetic electrokinetograph measurements of surface currents between these positions. Currents on the continental shelf were predominantly tidal. Strongest mean flows were found on the continental slope adjacent to areas where the continental shelf is narrowest. The flow on the west coast of the South Island was southwards south of 44° S, with a maximum mean speed at a depth of 100 m of 0.64 m.s‐1. On the east coast of the South Island the flow was generally towards the north, with a maximum speed at a depth of 100 m of 0.21 m.s‐1 near latitude 42° 30’ S.  相似文献   
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Recruitment of glass‐eels into freshwater is in two distinct phases characterised by behavioural differences: an initial invasion from the sea, and an upstream migration. Catches made at night in the Makara Stream, Wellington (41° 13'S, 174° 43’ E) indicate that the invasion by both New Zealand species commences in July, with that of the long‐finned eel Anguilla dieffenbachii Gray finishing by November, and that of the short‐finned eel A. ausiralis schmidlii Phillipps by December.

The length of post‐metamorphic sea‐life influences both morphology and behaviour of the glass‐eels. Differences in this period of sea‐life between early and late season glass‐eels explain the initial avoidance but later attraction of fresh water to the glass‐eels. Responses to fresh water also explain the preference for early season glass‐eels to invade on the flood tide and late season glass‐eels on the ebb tide. Neither the lunar cycle nor rainfall appear to be significant influences on invasion periodicity.  相似文献   
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