Litter dynamics and phenology of Melaleuca quinquenervia in south Florida

We monitored litterfall biomass at six different sites of melaleuca (Melaleuca quinquenervia (Cav.) S.T. Blake) forested wetlands in South Florida from July 1997 to June 1999. Annual litterfall of melaleuca varied between sites from 6.5 to 9.9 t dry wt ha(-1) yr(1) over the two-year period. Litterfall was significantly higher (p < 0.0001) in scasonally flooded habitats (9.3 t ha(-1) yr(1)) than in non-flooded (7.5 t ha(-1) yr(1)) and permanently flooded habitats (8.0 t ha(-1) yr(1)). Leaf fall was the major component forming 70% of the total litter, woody material 16%, and reproductive material 11%. Phenology of flowering and leaf flush was investigated by examination of the timing and duration of the fall of different plant parts in the litter traps, coupled with monthly field observations during the two-year study. In both years, flowering began in October and November, with peak flowers production around December, and was essentially completed by February and March. New shoot growth began in mid winter after peak flowering, and extended into the spring. Very little new growth was observed in melaleuca forests during the summer months, from May to August, in South Florida. In contrast, the fall of leaves and small wood was recorded in every month of the year, but generally increased during the dry season with higher levels observed from February to April. Also, no seasonality was recorded in the fall of seed capsules, which apparently resulted from the continual self-thinning of small branches and twigs inside the forest stand. In planning management for perennial weeds, it is important to determine the period during its annual growth cycle when the plant is most susceptible to control measures. These phenological data suggest that the appropriate time for melaleuca control in South Florida might be during late winter and early spring, when the plant is most active.

Perspektiven für die wichtigsten von der deutschen Fischerei genutzten Bestände für 1996

This article informs about the current status and development of fish stocks which are•of commercial importance for all branches of the German fisheries in the•entire North Atlantic. The information is based to a large extent on the reports of the Advisory Committee on Fishery Management (ACFM)of the International Council of the Sea(ICES) and in close connection with the results of scientific investigations of different institutes in Europe dealing with fish including the Institute for Sea Fisheries in Hamburg.

Les acadjas traditionnels dans le sud-est du Bénin

This study mission on acadja, the traditional way of fishing in the lagoons of the South-East part of Benin, permits us to understand how well-established this fishing practice is, in terms of time and spatial extention. The exploitation of acadja has a great profitability but it also represents the source of some problems as deterioration of branches, deforestation and social conflits. However, when acadjas are rationally exploited, they constitute a hope for waters which are in the process of losing their biological richness.

A preliminary study on the feasibility of using fenced brushparks for fish production in Lake Chilwa, Malawi

A study to investigate the feasibility of using fenced brushparks for fish ranching in Lake Chilwa was conducted for five months at the Kachulu Harbor. In a water depth of 1.4 m enclosures constructed from bamboo sticks embedded in the sediment and surrounded by a 13 mm seine net, were filled with three different subrates (Typha, bamboo, and Sesbania branches) and a no substrate enclosure served as a control. Netting materials contributed 57 per cent towards the total cost (US$ 0.24-0.30/m2) of brushpark contruction. Fish productivity was highest in the Typha, bamboo and control treatments and lowest in the Sesbania treatments. The decomposition of substrates did not affect water quality. The results indicate that enclosed brushparks may be a feasible technology for enhancing fish yields and providing alternative income sources to fisherfolk in small lakes and water bodies.

Stanford University’s John Otterbein Snyder: Student, Collaborator, and Colleague of David Starr Jordan and Charles Henry Gilbert

John Otterbein Snyder (1867–1943) was an early student of David Starr Jordan at Stanford University and subsequently rose to become an assistant professor there. During his 34 years with the university he taught a wide variety of courses in various branches of zoology and advised numerous students. He eventually mentored 8 M.A. and 4 Ph.D. students to completion at Stanford. He also assisted in the collection of tens of thousands of fish specimens from the western Pacific, central Pacific, and the West Coast of North America, part of the time while stationed as “Naturalist” aboard the U.S. Fish Commission’s Steamer Albatross (1902–06). Although his early publications dealt mainly with fish groups and descriptions (often as a junior author with Jordan), after 1910 he became more autonomous and eventually rose to become one of the Pacific salmon, Oncorhynchus spp., experts on the West Coast. Throughout his career, he was especially esteemed by colleagues as “a stimulating teacher,” “an excellent biologist,” and “a fine man.

Ecological imbalances in the coastal areas of Pakistan and Karachi Harbour

The marine environment of Pakistan has been described in the context of three main regions : the Indus delta and its creek system, the Karachi coastal region, and the Balochistan coast. The creeks, contrary to concerns, do receive adequate discharges of freshwater. On site observations indicate that freshwater continues flowing into them during the lean water periods and dilutes the seawater there. A major factor for the loss of mangrove forests as well as ecological disturbances in the Indus delta is loss of the silt load resulting in erosion of its mudflats. The ecological disturbance has been aggravated by allowing camels to browse the mangroves. The tree branches and trunks, having been denuded of leaves are felled for firewood. Evidence is presented to show that while indiscriminate removal of its mangrove trees is responsible for the loss of large tracts of mangrove forests, overharvesting of fisheries resources has depleted the river of some valuable fishes that were available from the delta area. Municipal and industrial effluents discharged into the Lyari and Malir rivers and responsible for land-based pollution at the Karachi coast and the harbour. The following are the three major areas receiving land-based pollution and whose environmental conditions have been examined in detail: (l) the Manora channel, located on the estuary of the Lyari river and serving as the main harbour, has vast areas forming its western and eastern backwaters characterized by mud flats and mangroves. The discharge of industrial wastewater from the S.I.T.E. and municipal effluents from the northern and central districts into the Lyari has turned this river into an open drain. This, in turn, has caused a negative impact on the environment of the port, fish harbour, and the adjacent beaches. (2) The Gizri creek receives industrial and municipal effluents from the Malir river as well as from several industries and power stations. The highly degraded discharges from the Malir have negatively impacted the environment in this creek. (3) The coastline between the Manora channel and Gizri creek where the untreated municipal effluents are discharged by the southern districts of Karachi, is responsible for the degraded environment of the Chinna creek, and also of the beaches and the harbour. The Balochistan coast is relatively safe from land-based pollution, mainly because of the lack of industrial, urban or agricultural activity, except the Hingol river system where some agricultural activities have been initiated.

Survival rates of different postlarval stages of Penaeus monodon Fabricius

The objective of this study is to determine survival rates of different postlarval stages upon stocking in the Leganes ponds. Twelve 3m x 2m x 2m suspension nets made of nylon cloth (mesh size = 0 . 1 mm) were set up in a Leganes Station pond (ave. water depth = 1 m) by means of 3-m long poles stacked at distances approximating the area of each net. The net bottom was filled with topsoil at least 15 cm thick to stimulate the pond bottom. At least 60 cm of the upper edge of each net was above the water level to prevent mixing of water inside and outside the net. P.monodon of stages P SUB-11 , P SUB-15 , P SUB-21 (from the hatchery) and P SUB-25 (from the wet lab) were stocked in the nets at 200/sq m or 1,200 fry/net. Due to lack of fry, only one P SUB-25 net was stocked. Each net had two large dried miapi branches as shelter from predation and cannibalism for the young sugpo fry. Fresh lablab was fed at the rate of one pail (approximately 5 kg) every four days per net. Harvest data show relatively higher survival rates for P SUB-15 and P SUB-18 compared to P SUB-11 and P SUB-25 with no significant difference between these two stages. The results for P SUB-25 may not be valid because the stock came from the wet lab in comparison to the other postlarval stages which were reared in the hatchery. Moreover, the P SUB-25 stock had no replicates and the net itself (no. 10) was discovered to have many holes. These preliminary results point to P SUB-15 as the best stage for harvest from the hatchery in terms of high pond recovery and lesser expense in rearing compared to older postlarvae.

Water quality assessment of Sonbolrood River by using hylsenhof index

This research investigates the quality of sonbolrood river by using Hylsenhof HFBI indicators and identified Macroinvertebrates invertebrates community in the family level. This study took place during 1388-1389 with four sampling season in four stations respectively in the forests of Kalyj kheyl village in Savadkuh (first station), industrial area of Islamabad (second Station), earth dam of Sonbolrood (third station) and the Place crosses Sonbolrood with Babolrood river (fourth Station). Macroinvertebrates invertebrates collected by quantitative sampler of Sorbr and they were isolated in laboratory by loop and they were identified in the family level. Generally, Macroinvertebrates of Sonbolrood river were formed three branches: Arthropods and flat worms and mollusks, including 3 tiers, 6 orders and 14 families that showed the maximum diversity and density in autumn and the least diversity and density in summer at all stations, also the third and fourth stations respectively were highest and lowest diversity and density. The water quality of Sonbolrood river based on the water quality Guide(Hylsenhof) is evaluated with excellent condition for all stations except third station. Sonbolrood river with having high slope, rocky and sandy bed, with self-refining act, completely is a proper ecosystem for aquatic organisms, but it is done due to increased organic matter and sewage factory located in industrial zone in the third station and then the increased water pollution caused by nurturing the water warm fish in the earth dam of Sonbolrood. (because of this, the water quality at third station based on the water quality Guide(Hylsenhof) are evaluated in a fairly good condition) and adding domestic sewages of adjacent villages like Seyedkola village and Shirdarkola caused increased pollution and increased trophy of Macroinvertebrates that are resistant to pollution and affect upon Macroinvertebrates community.

Ecological impact of Mahshahr petrochemical activities on abundance and diversity of macrobenthic fauna in Zangi Creek (Persian Gulf)

The Moosa Creek extends from its opening into the Persian Gulf, with some sub narrow creeks leading to it. Zangi creek is one of the main branches of Moosa creek. The creek contains numerous sources of organic pollution, including sewage outlet flows and boat waste. After establishing the Petrochemical special Economic Zone (PETZONE) in 1997 near to the Zangi Creek, the pipelines, streets and railway made it distinct from eastern and western parts of this creek. Industrial activities have released sludge and effluents in this creek along these years. A survey of the Zangi creek was performed, assessing water properties, organic pollution, and the population density, distribution and diversity of macrobenthic fauna through bi-monthly sampling from July 2006 to September 2007. Samples were collected from water near the bottom and sediment at 7 stations include 2 stations inside the distinct Zangi creek and 4 stations along a transect with 1 km distances between them in eastern free part and one reference station located at the Persian Gulf entrance to the Moosa creek. The environmental parameters such as temperature, salinity, pH, dissolved oxygen, COD, turbidity, EC and heavy metals include Hg, Cd, Pb, Ni as well as percentage silt-clay and total organic matter of the sediment were measured. The faunal population density and their distribution are discussed in relation to the environmental changes. Results showed spatial heterogeneity in faunal distribution of the Zangi creek. Nine groups of macrofauna were identified out of distinct zangi creek. Polychaets formed the dominant group (48%) followed by bivalves (13%), gastropods (10%), Decapods (2%), Tanaids (5%), and all other groups (22%). The distinct creek was heavily polluted without any macrofauna communities probably as a consequence of the high pH, COD, low salinity and heavy metals contamination specially Cd and Pb. The other stations near to the disposal site were found with macrofauna communities commonly tolerant to organic pollution, At 3 km east of the disposal site, macrofauna is comparable to the surrounded creek, whereas macrofauna still indicate environmental degradation. Farther a way, faunal density decreases and equilibrium taxa gradually replace opportunistic species, while the other stations were far from polluted area contained lower pollution and relatively healthy macrofauna. The mean biomass of macrobenthic fauna were estimated for the whole studied area. The results are considered in Minimum density and biomass in surrounded creek and maximum density and biomass in 3 km of surrounded area. Biodiversity Indices were low in surrounded creek. The Shanon-weaver information index was used to describe the spatially variations in diversity. Macrofauna density, shanon and simpson index were significantly variable between surrounded and free parts of Zangi creek (p<0.05). The numerical abundance of macrobenthose varied from 221. m-2 in polluted area to 4346 m-2 in free part of Zangi creek. The Shanon-weaver information index varied from 0.4 in distinct area to 2.9 in reference station. The physico- chemical changes between distinct and free creeks showed significant variations such as pH, salinity and EC. Salinity and EC were significantly positive correlate to macrofauna density, whereas pH and TOM percentage indicated significantly negative correlation to density. Heavy metals concentrations in sediments were higher than water samples. Concentration pattern of heavy metals in sediments and water samples were Ni>Pb>Cd>Hg. Salinity and pH were significantly correlated to metals in sediments (p<0.01). No significant correlation were found between Macrofauna density and heavy metals (p<0.05).

La estructura y reproducción de Acanthococcus antarcticus Hooker et Harvey

The present paper gives a full description of the organization of Acanthococcus antarcticus Hooker et Harvey, a not well known member of the Rhodophyllidaceae as well as gives for the first time description of the male and tetrasporic plants. Detailed organization of the carpogonial branches, spermatia and tetraspores is also presented. Nineteen figures illustrate the text (material collected at Deseado port, Santa Cruz prov., Argentina). The following text is the content of the discussion. From the description it is possible to confirm the position of Acanthococcus in the Rhodophyllidaceac as was done by Kylin (Kylin 1960, p. 290 et seg.). It has many similarities in the development of the carpogenic branches and in the formation of spermatia as well in the production of the zonately divided tetrasporangia with the genera of the family whose reproduction is known; Cystoclonium purpureum (Hudson) Batters and Rhodopyllis bifada (Good. et Woodw.) Kützing (Kylin 1923); Calliblepharis jubata (Good. et Woodw.) Kützing (Kylín 1928) and Craspedocarpus erosus (Hook. et Harvey) Sehmitz (Kylin 1932). Apparently the distinguishing feature of Acanthococcus is the structure of the vegetative frond, with the abundant development of rhizoidal filaments in the medula, besides the characteristic appendages of the cystocarps. Harvey's figure (Harvey 1847, P. 181, Fig. 3) of the tranverse section of the plant shows the central portion composed of a dense small-celled medula limited by a region of large cells which is externally covered by a small-celled cortex. As we have seen the small-celled filaments are not restricted to the central portion, but extend into the large-celled portion and can reach the cortex. On the other hand, the eros section of Acanthococcus depicted by Kützing (Kützing 1867, T. 93, Fig. h, under Callophyllis antartica), apparently belongs to another plant, so different in the structure when one compares his figure with Harvey's and the ones in this paper. RESUMEN EN ESPAÑOL Este trabajo presenta una completa descripción de la organización de Acanthococcus antarcticus Hooker et Harvey, un miembro poco conocido de las Rodofilidáceas, así como presenta por primera vez descripciones de las plantas masculinas y de las tetraspóricas. También por primera vez es presentada la organización detallada de las ramas carpogoniales, de los espermecios y de las trásporas. Diecinueve figuras completan el texto (material coleccionado en Puerto Deseado, Prov. Santa Cruz, Argentina).