scholarly journals Population structure and reproductive status of the invasive Eriocheir sinensis (Decapoda, Varunidae) in the Tagus estuary (Portugal)

Limnetica ◽  
2018 ◽  
pp. 47-59
Author(s):  
Anastácio, Pedro M. ◽  
Marques, Mónica ◽  
Águas, Maria ◽  
Wójcik-Fudalewska, Dagmara ◽  
Normant-Saremba, Monika
Keyword(s):  
Population Structure ◽  
Eriocheir Sinensis ◽  
Reproductive Status ◽  
Tagus Estuary

Genetic diversity and population structure of the Chinese mitten crab Eriocheir sinensis in its native range

2009 ◽  
Vol 156 (8) ◽  
pp. 1573-1583 ◽  
Author(s):  
Liying Sui ◽  
Fumin Zhang ◽  
Xiaomei Wang ◽  
Peter Bossier ◽  
Patrick Sorgeloos ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Eriocheir Sinensis ◽  
Native Range ◽  
Chinese Mitten Crab ◽  
Mitten Crab

Diet and feeding ecology of Eriocheir sinensis on the Polish coast of the Baltic Sea and in the Tagus Estuary, Portugal

2019 ◽  
Vol 48 (3) ◽  
pp. 236-246 ◽  
Author(s):  
Dagmara J. Wójcik-Fudalewska ◽  
Monika Normant-Saremba ◽  
Agata Kolasa ◽  
Pedro M. Anastácio
Keyword(s):  
Feeding Ecology ◽  
Eriocheir Sinensis ◽  
Tagus Estuary ◽  
Vistula Lagoon ◽  
Stomach Fullness ◽  
Gulf Of Gdańsk ◽  
The Baltic Sea ◽  
Gulf Of Gdansk ◽  
The Baltic ◽  
The Vistula Lagoon

Abstract The feeding ecology of the Chinese mitten crab Eriocheir sinensis was studied by analyzing the stomach fullness and its content with regard to sex, size and brackish water habitats occurring on the coast of the Baltic Sea (Gulf of Gdańsk and Vistula Lagoon, Poland) and the Atlantic (Tagus Estuary, Portugal). The presented results show that neither the site, sex (except the Gulf of Gdańsk) nor the size of an individual had a significant (p > 0.05) effect on the stomach fullness of E. sinensis. However, the type of food consumed was significantly (p < 0.05) correlated with the inhabited locality. The stomachs of crabs contained the remains of animal and plant origin, as well as detritus. The remains of animals (Bivalvia, Amphipoda, Gastropoda and Polychaeta) were more frequently found in the crabs from the Gulf of Gdańsk, while the remains of plants (Tracheophyta, Chlorophyta) were most often found in the stomachs of crabs from the Vistula Lagoon and the Tagus Estuary. Detritus was found only in the Gulf of Gdańsk and the Vistula Lagoon. Research indicates that the feeding ecology of omnivore E. sinensis is habitat specific, which should be taken into account when assessing the risk associated with this invasive species.

Distribution, abundance, population structure and activity of Halobatrachus didactylus in the Tagus estuary (Portugal) and adjacent coastal waters

2011 ◽  
Vol 93 (2) ◽  
pp. 405-412 ◽  
Author(s):  
João Carlos Cotter ◽  
Tadeu José Pereira ◽  
Maria José Costa ◽  
José Lino Costa
Keyword(s):  
Population Structure ◽  
Coastal Waters ◽  
Low Frequency ◽  
Late Summer ◽  
Tagus Estuary ◽  
Water Current ◽  
Western Coast ◽  
Distinct Features ◽  
Discrete Populations ◽  
Structure And Activity

The Lusitanian toadfish Halobatrachus didactylus is a demersal teleost and the only species of the family Batrachoididae that occurs along the continental Portuguese coast. It is a subtropical species that is more abundant in the south of Portugal, whereas along the western coast it is concentrated in discrete populations, located in estuaries and coastal recesses. The distinct features of these estuaries have revealed important changes in the respective Lusitanian toadfish populations, namely particularities in their distribution and population structure, and also in the morphology and breeding behaviour of the specimens. A survey covering 31 stations in the Tagus estuary, Portugal, and adjacent coastal waters sampled these stations over an 18 month period. This study characterized the distribution, abundance, population structure and activity of H. didactylus in this coastal zone. Toadfish showed a preferential distribution in the intermediate and lower estuarine stretches, and was more abundant in the Montijo Bay, a small bay within the Tagus estuary. Three length-groups were identified, with larger specimens more abundant in deeper areas. The specimens also revealed a preference for areas of higher water temperature, low water current and muddy substrates. Female specimens were slightly more abundant than males and type II males had a very low frequency of occurrence (3.2%). Captures of toadfish were high in spring and late summer and very low in winter.

Population-Structure and Reproductive Status of Koalas on Raymond Island, Victoria

1988 ◽  
Vol 15 (5) ◽  
pp. 511 ◽  
Author(s):  
PJ Mitchell ◽  
R Bilney ◽  
RW Martin
Keyword(s):  
Population Structure ◽  
Reproductive Tract ◽  
Older Age ◽  
Reproductive Status ◽  
Age Classes ◽  
Tract Disease

In December 1980, 87 adult (>1-year-old) koalas (36 males, 51 females) were captured and marked on Raymond Island, in the Gippsland Lakes of Victoria. A further 85 adults and 34 juveniles (6-12 months old) were sighted but not captured. In August 1985, 25 females and 24 males were captured and examined. The proportions of animals in the older age classes (age classes 4 and above) were 61% in 1980 and 39% in 1985, while the reproduction rates were 38 and 40%, respectively. The low reproduction rates, and the high proportions of older animals in 1980, were attributed to reproductive tract disease, although the presence of this disease did not prevent the population from increasing to a density at which trees were being overbrowsed.

scholarly journals Wildlife population, structure and reproduction based on hunters’ returns to a bush meat market in Abeokuta, Ogun state, Nigeria

2019 ◽  
Vol 6 (1) ◽  
pp. 541
Author(s):  
Muideen Alade Yisau ◽  
Israel Oluyinka Oloyede Osunsina ◽  
Samuel Akinyele Onadeko
Keyword(s):  
Population Structure ◽  
Animal Species ◽  
Wild Animal ◽  
Reproductive Status ◽  
Sex Structure ◽  
Age Class ◽  
Ogun State ◽  
Wildlife Population ◽  
Bush Meat ◽  
Meat Market

Assessment of the population structure and reproductive status based on hunters’ returns to bush meat market were carried out in Ogun state, Nigeria. Information on animal species was collected before they are dissected or processed; names of species, age class, sex, weight and sources. After dissection, its reproductive status viz number of foetus and stages of development were observed. The data collected covered a period of three months. The result from the study showed that nine hundred and eighty-nine animals were returned by hunters to the market within the period. The highest hunters’ returns occurred at week four while the highest returns were also during the first four weeks. Canerat (Thryonomys swinderianus) and Maxwell duiker (Cephalophus maxwelli) were animals with the highest frequency returned. The result shows that 342 fetuses were recorded from all the species. The highest of fetuses was from Cane rat and Maxwell duiker. Seven orders of mammals were discovered in the population and rodentia had the highest percentage followed by artiodactyla. In terms of sex structure of the wild animal returned, female had the highest population (558) than male which has 431 animals. Also, for the age class structure, the adult had the highest frequency and percent than the sub-adult and juvenile. The patterns of returns by hunters from various sources showed that the highest animal return was from Tibo (157) and the least from Oba (8). The highest mean weight of animals returned was 19.0±0.00kg and the least mean weight of animal was 0.46±0.22kg. It is therefore, recommended that wildlife resources should be treated as an asset to be conserved, managed and given emphasis in land management for the benefit of all humanity. Vigorous efforts towards checking indiscriminate hunting of animals of all sexes and reproductive conditions must be pursued.

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