Occurrence and abundance of young mullet Mugil liza (Teleostei: Mugilidae) in the surf zone along the southern coast of Brazil

The southern population of Mugil liza is distributed from Argentina (47°S) to the state of São Paulo, Brazil (23°S). Young mullets use the estuaries as nursery grounds, and prior to recruitment into estuaries they use the surf zone as a temporary habitat. Based on 12 consecutive months of sampling, this study used generalized linear models (GLM) to analyse the relationships between environmental variables and the presence and relative abundance of young mullets in the surf zone adjacent to six major estuaries in southern Brazil (between 29°S and 33°S). Young mullets were present in all seasons over the sampling period, but the probability of occurrence was higher in winter and was associated with low temperatures. The water temperature alone explained more than half of the total deviance of the GLM models for presence (23%) and abundance (21%) of young mullets in the surf zone. Site 2 (Rio Grande) had lower temperatures in the colder months, the highest probability of occurrence of all collection sites and the greatest abundance (n=3402) of young M. liza, which represented 52% of the total of individuals (n=6493) caught among the six sites sampled.

The diversity and distribution of chigger mites associated with rodents in the South African savanna

Chigger mites (Trombiculidae) are temporary habitat-specific ectoparasites that often occur on rodents. Little ecological data are available on chiggers associated with rodents in South Africa. The study aims were to (1) record the chigger species associated with rodents in the savanna, (2) assess if chigger species display parasitope preference on the rodent body and (3) compare the distribution of chigger species in natural, agricultural and urban habitats. Rodents (n = 314) belonging to eight genera were trapped in the savanna biome during 2014 and 2015. Twelve chigger species, of which five are recently described species, were recorded from 161 rodent hosts. The data include three new country locality records. Microtrombicula mastomyia was the most prevalent species across sampling seasons and habitat types. Significant parasitope preference was recorded for two species, with the ear, face and tail base some of the preferred attachment sites. Sampling season and habitat type had a significant effect on chigger communities with summer and agricultural habitats recording the highest species richness, while the highest species diversity was recorded in natural habitats. The study contributes to our current knowledge regarding rodent-associated chigger diversity and distribution in South Africa and further highlights the importance of environmental characteristics in shaping chigger communities.

Sea catfishes (Ariidae) feeding on freshwater floodplains of northern Australia

Flooding of the terminal floodplains of northern Australian rivers provides a greatly expanded, productive habitat accessed by both freshwater and estuarine fishes. This study aimed to determine the extent to which sea catfishes (Ariidae) make use of floodplains and the reasons for doing so (i.e. spawning, feeding). Nine species were collected from floodplains and adjacent distributaries of the Mitchell and Flinders rivers; floodplain use was largely restricted to freshwater species. Evidence of prior wet season spawning was recorded for some species, and mesenteric lipid deposits indicated that fish were in good condition. However, little evidence of spawning on floodplains was found. Stomach content analysis and stable isotope analysis indicated dietary partitioning, particularly between freshwater and estuarine species, but also within freshwater species, and indicated that some species were responsive to variations in food availability. Isotope analyses suggest extensive movement between freshwater, estuarine and marine habitats at different life history stages for the catfish assemblage studied. Terminal floodplains of northern Australian rivers provide important temporary habitat for adult sea catfishes to feed upon, but do not appear to be used as spawning grounds.

Do Corncrakes Crex crex benefit from unmown refuge strips?

SummaryCorncrakes Crex crex mainly breed in grassland, where they are threatened by mowing. Conservation requires delayed mowing or modified mowing methods. In large fields, it has been suggested that leaving strips of uncut grass may reduce mortality, especially of unfledged chicks. We attended mowing operations (2012–2015) in the Lower Oder Valley National Park in north-eastern Germany, where 10-m refuge strips were introduced. We documented the escape behaviour of adults and chicks and their use of refuge strips by observations and radio-telemetry. Flightless chicks crossed significantly shorter distances of mown area (< 20 m) than adults. When mowing from the outside inwards, chicks were not able to successfully escape to the field edge at > 31 m, adults at > 60 m distance to the edge and returned to the unmown block. Twenty-three percent of adults, 30% of families and 49% of independent chicks survived in 10 m-wide strips until such strips were either mown or left as refuges. Whereas adults departed the strips the next day, independent chicks stayed for up to 22 days after mowing in 15–30 m wide refuges. We recommend refuge strips for breeding sites where more effective measures cannot be applied. Farmers face less additional effort and lower financial losses compared with delayed mowing. A width of 10 m should be considered as the absolute minimum, because most birds left the cover already > 10 m for the first time and only wider refuges served as temporary habitat for young.

Segara Anakan Lagoon (SAL): Fish Biodiversity and the Ecological Role

Two life stages of fish were sampled to examine the fish biodiversity and the ecological role of Segara Anakan lagoon (SAL). The fish were observed in during 2004 – 2014 while the larvae were sampled twice monthly during the full moon and dark periods in daylight hours only over 11 month periods (Novembre 2005 to Septembre 2006) at 10 sites located at SAL, Cilacap. Each trip two samples of the high tide and low ebb periods were taken from each station. The mature fish were sampled at Klaces and Karanganyar. The fish were also collected from fisherman. At least 90 genera of 48 family (65 mature fish and 64 larvae) were recorded at SAL. Gobbidae (range between 67.3 – 72.9 %) and Engraullidae (16.7 – 19.3 %) are the two most abundant larvae captured. Of the fish, at least 40 genera belongs to 16 families are of resident species that inhabit SAL for whole their life cycles. In other hand, 50 genera belongs to 31 families use SAL as temporary habitat (migratory). This finding suggests the important ecological role of SAL for fish.Keywords : segara anakan lagoon, biodiversity, ekological role