Toxic blue-green algae: The "problem" in perspective

The incidence of blue-green algal blooms and surface scum-formation are certainly not new phenomena. Many British and European authors have been faithfully describing the unmistakable symptoms of blue-green algal scums for over 800 years. There is no disputing that blue-green algal toxins are extremely harmful. Three quite separate categories of compound have been separated: neurotoxins; hepatotoxins and lipopolysaccharides. There is a popular association between blue-green algae and eutrophication. Certainly the main nuisance species - of Microcystis, Anabaena and Aphanizomenon are rare in oligotrophic lakes and reservoirs. Several approaches have been proposed for the control of blue-green algae. Distinction is made between methods for discharging algae already present (eg algicides; straw bales; viruses; parasitic fungi and herbivorous ciliates), and methods for averting an anticipated abundance in the future (phosphorous control, artificial circulation etc).

Effects of the Santa Barbara, Calif., Oil Spill on the Apparent Abundance of Pelagic Fishery Resources

Many studies have been made of the effects of oil on marine invertebrates, plants (marine algae and phytoplankton), and vertebrates such as seabirds and marine mammals. An excellent review of these findings, which includes some references to fish and pathological effects of aromatic hydrocarbons, has been published by the Royal Society, London (Clark, 1982). That review dealt with the environmental effects of such major oil spills or releases such as those by the tankers Torry Canyon (119,000 t) on the south coast of England, Metula (50-56,000 t) in the Straits of Magellan, Argo Merchant (26,000 t) off Cape Cod, and the super tanker Amoco Cadiz (223,000 t) on the coast of northern Brittany. Those spills were studied to determine their effect on living resources. In contrast there are few references on the impact of oil spills on pelagic fishery resources.

Spatial and temporal variability in the distribution and abundance of larval and juvenile fishes associated with pelagic Sargassum

A survey of the larval and juvenile fishes associated with the pelagic Sargassum habitat in the South Atlantic Bight and adjacent western Atlantic Ocean was conducted from July 1991 through March 1993. Fishes representing 104 taxonomic categories were identified, including reef fishes, coastal demersal, coastal pelagic, epipelagic and mesopelagic species. The most important families were Balistidae and Carangidae, each represented by 15 species. Species composition, species diversity and abundance varied both seasonally and regionally. Diversity was highest during spring through fall over the outer continental shelf and in the Gulf Stream. Abundance decreased from spring through winter and from the continental shelf into offshore waters. The numbers of fishes and fish biomass were found to be positively correlated with the wet weight of algae in most cases examined. The results of this study will be useful to fisheries managers assessing the potential impacts of commercial Sargassum harvesting in the region.

Algae and water pollution in Mahi Estuary

Distribution of phytoplankton, chlorophyll A and phaeophytin was studied at different locations in the Mahi Estuary, Gujarat, India during 1982. The water quality at the discharge point was poor while the region away from it was relatively unpolluted. The results indicated a wide range of variation in phytoplankton population (7.68-5010, 96 x 10 super(4) cells/l, chl. a 2.22-58.22 mg/m super(3) and phaeophytin [0.20-10.21 mg/m super(3)]. The ratio of chl. a/phaeophytin were remarkably low at highly polluted stations. Higher abundance of the genera Oscillatoria and Nitzschia were recorded at polluted stations. The diversity of species at the unpolluted station was higher (1.56) as compared to the polluted station (1.07).

Growth and reproductive performance of locally isolated brackish water rotifer (Brachionus plicatilis) feeding different micro algae

Population growth and reproductive capacity of brackishwater rotifer, Brachionus plicatilis, were evaluated, for a period of 8 days in a temperature controlled ( =25°C) microalgallaborarory, under three different algal feeding regimens. The algal species that were tested are: (i) Chlorella sp. (T1), Tetraselmis chui (T2), Nannochloropsis oculata (T 3). The feeding density of each algal species was maintained similar as of 4.5xW6 ceHs mi. The rotifer fed on T. chui showed the highest (p<0.05) population growth (131.5 ind./ml), compared to that fed on Chlorella sp (45.67 ind./ml) and N oculata (43.44 ind./ml). The abundance of egg bearing rotifers was also higher (35.77%) with T. chuithan with Chlorella sp (27.76%) and N oculara (24.60%). The results of the present study indicate that T. chui could be the most suitable algal food for the stock culture of locally isolated rotifer B. plicatilis.

The diversity and abundance of zooplankton in the Lake Victoria and Kyoga basins and their relationship to fish production

Biological diversity of an ecosystem is considered a reliable measure of the state of health of the ecosystem. In Uganda's large lakes, the Victoria and Kyoga, the past three decades have been characterized by profound changes in fish species composition following the introduction of the piscivorous Nile perch (Oguto-Ohwayo 1990). Over 300 haplochromine cichlid species comprising a wide range of trophic groups were lost along with a host of non-cichlid fishes which occupied virtually all available ecological niches and in the lakes (Witte 1992). A second major ecological event has been the gradual nutrient enrichment of the water bodies (eutrophication) from diffuse and point sources, while at the same time pollutants have also gained entrance into the water systems in pace with indusfrial development and human population increases in the lake basins. Eutrophication and pollution have drastically altered the physical and-chemical character of the water medium in which different fauna and flora thrive. In Lake Victoria these alterations have resulted in changes of algal species composition from pristine community dominated by chlorophytes and diatoms (Melosira etc) to one composed largely of blue-green algae or Cyanobacteria (Microcystis, Anabaena, Planktolyngbya etc) (Mugidde 1993, Hecky 1993).

A Preliminary Check-List of the Marine Algae of the Moss Landing Jetty: An Annotated Floristic Compilation. Annual Report, Part 7, 1973

(PDF contains 55 pages)

Observations of the biological communities at Bolsa Chica artificial reef

Bolsa Chica Artificial Reef (BCAR) was constructed in November 1986 with 10,400 tons of concrete rubble and eight concrete and steel barges. Prior to any additional augmentation of BCAR, the u.s. Army Corps of Engineers and the California Coastal Commission required the California Department of Fish and Game (CDFG) to survey the bioloqical communities on and around BCAR. In April 1992, qualitative surveys of the biological communities were conducted on one of the eight modules at BCAR and at a nearby sand-only site. One of the modules, Module D, located in 90 feet of water (MLLW), was surveyed for fish, macroinvertebrates, and turf community organisms (small plants and sessile animals). Twelve species of fish were observed, including kelp bass (Paralabrax clathratus) and barred sand bass (P. nebulifer). Eight macroinvertebrate species were observed, rock scallops (Crassedoma giganteum) being the most abundant. The turf community was comprised of thirteen invertebrate taxa, among which erect ectoprocts (Bugula spp.) were the most numerous. Two species of foliose red algae (Rhodymenia pacifica and Anisocladella pacifica) were also observed. The reef has reached an advanced stage of successional development with fish and invertebrate communities diverse and well established. However, due,.to its depth and the turbidity of surrounding waters, this reef is not likely to ever support a diverse algal community. The diversity and abundance of fish and macroinvertebrates were, as to be expected, much lower in the nearby sand-only site. Only two species of fish and seven macroinvertebrate species were observed. Of these, only the sea pen, Stylatula elongata, was common. Overall, when compared to nearby sand-only habitats, Bolsa Chica Artificial Reef appears to contribute substantially to the local biological productivity. In addition, the concrete rubble used in BCAR' s construction appears to be performing as well as the quarry rock used in all of CDFG's experimental reefs. (Document pdf contains 22 pages)

Population Characteristics of Largemouth Bass Associated with Changes in Abundance of Submersed Aquatic Vegetation in Lake Seminole, Georgia

Population characteristics of largemouth bass ( Micropterus salmoides L.) including growth, body condition (relative weight), survival, and egg production were examined in relation to abundance of submersed aquatic vegetation (SAV) coverage (primarily hydrilla [ Hydrilla verticillata L.f. Royle]) in three embayments of Lake Seminole, GA, and compared to a previous study conducted in 1998. (PDF has 8 pages.)

Relative tolerance of mat-forming algae to copper

This study documents the relative tolerance of the common, weedy mat-forming green algae Hydrodictyon , Oedogonium , Pithophora , Rhizoclonium , and Spirogyra to copper. In addition, the copper tolerance of the cyanobacterial (blue-green algal) mat-forming Oscillatoria was assessed.

Euhrychiopsis lecontei distribution, abundance, and experimental augmentations for Eurasian watermilfoil control in Wisconsin lakes

The specialist aquatic herbivore Euhrychiopsis lecontei (Dietz) is currently being researched as a potential biological control agent for Eurasian watermilfoil (Myriophyllum spicatum L.). Our research in Wisconsin focused on 1) determining milfoil weevil distribution across lakes, 2) assessing limnological characteristics associated with their abundance, and 3) evaluating milfoil weevil augmentation as a practical management tool for controlling Eurasian watermilfoil.

Bowhead and white whale migration, distribution, and abundance in the Bering, Chukchi, and Beaufort Seas, 1975-78

From September 1975 to September 1977 we conducted field research on bowhead, Balaena mysticetus, and white, Delphinapterus leucas, whales in the U.S. Bering, Chukchi, and Beaufort Seas. The objectives were to determine the general distribution and migration of these whales in spring and autumn and to estimate abundance. We also surveyed the literature beginning in June 1975 through March 1978 to augment our empirical results. (PDF contains 48 pages)

Relationships between Larval and Juvenile Abundance of Winter-Spawned Fishes in North Carolina, USA

We analyzed the relationships between the larval and juvenile abundances of selected estuarine-dependent fishes that spawn during the winter in continental shelf waters of the U.S. Atlantic coast. Six species were included in the analysis based on their ecological and economic importance and relative abundance in available surveys: spot Leiostomus xanthurus, pinfish Lagodon rhomboides, southern flounder Paralichthys lethostigma, summer flounder Paralichthys dentatus, Atlantic croaker Micropogonias undulatus, and Atlantic menhaden Brevoortia tyrannus. Cross-correlation analysis was used to examine the relationships between the larval and juvenile abundances within species. Tests of synchrony across species were used to find similarities in recruitment dynamics for species with similar winter shelf-spawning life-history strategies. Positive correlations were found between the larval and juvenile abundances for three of the six selected species (spot, pinfish, and southern flounder). These three species have similar geographic ranges that primarily lie south of Cape Hatteras. There were no significant correlations between the larval and juvenile abundances for the other three species (summer flounder, Atlantic croaker, and Atlantic menhaden); we suggest several factors that could account for the lack of a relationship. Synchrony was found among the three southern species within both the larval and juvenile abundance time series. These results provide support for using larval ingress measures as indices of abundance for these and other species with similar geographic ranges and winter shelf-spawning life-history strategies.

Life History, Diet, Abundance and Distribution, and Length-Frequencies of Selected Invertebrates in Florida Bay, Everglades National Park, Florida

This report presents information on the life history, diet, abundance and distribution, and length-frequency distributions of five invertebrates in Florida Bay, Everglades National Park. Collections were made with an otter trawl in basins on a bi-monthly basis. Non-parametric statistics were used to test spatial and temporal differences in the abundance of invertebrates when numbers were appropriate (i. e., $25). Invertebrate species are presented in four sections. The sections on Life History, and Diet were derived from the literature. The section on Abundance and Distribution consists of data from otter-trawl collections. In addition, comparisons with other studies are included here following our results. The section on Length-frequency Distributions consists of length measurements from all collections, except 1984-1985 when no measurements were taken. Length-frequency distributions were used, when possible, to estimate life stage captured, spawning times, recruitment into Florida Bay for those species which spawn outside the Bay, and growth. Additional material from the literature was added when appropriate. (PDF contains 39 pages)