Conservation Biology of Elasmobranchs

Elasmobranchs are vital and valuable components of the marine biota. From an ecological perspective they occupy the role of top predators within marine food webs, providing a regulatory control that helps balance the ecosystem. From an evolutionary perspective, this group represents an early divergence along the vertebrate line that produced many unusual, but highly successful, adaptations in function and form. From man's perspective, elasmobranchs have been considered both an unavoidable nuisance, and an exploitable fishery resource. A few of the large shark species have earned a dubious notoriety because of sporadic attacks on humans that occur in coastal areas each year worldwide; the hysteria surrounding an encounter with a shark can be costly to the tourist industry. More importantly, elasmobranchs are often considered a detriment to commercial fishing operations; they cause significant economic damage to catches and fishing gear. On the other hand, consumer attitudes have changed concerning many previously unpopular food fishes, including elasmobranchs, and this group of fishes has been increasingly used by both recreational and commercial fishing interests. Many elasmobranchs have become a popular target of recreational fishermen for food and sport because of their abundance, size, and availability in coastal waters. Similarly, commercial fisheries for elasmobranchs have developed or expanded from an increased demand for elasmobranch food products. (PDF file contains 108 pages.)

Paciano II: the report of a conversation on whaling and science, 1-3 March 2008 (Paciano, Umbria)

In 2006 the UK-based charity, Global Ocean, with local support from the Third Millennium Foundation, convened a Conversation among specialists about the problems facing the conservation of whales. Called "A consultation on whaling", this gathering was held in the ancient village of Paciano, in Umbria near the border with Tuscany, 15 – 17 October 2006. There were 15 participants from 11 countries. Dr Kees Lankester served as moderator. The outcome was an Aide Memoire which served to guide the participants in the run-up to the 2007 meeting of the International Whaling Commission (IWC), held in Anchorage, Alaska, in June. One point of agreement was that a second consultation should be held in the months following the Anchorage meeting, involving some but not necessarily all of the participants in the first, but concentrating this time on scientific issues – especially those encountered in the Scientific Committee of the IWC –with particular attention to informing a wider public about those scientific activities in relation to the problems confronting the IWC and the views of scientists about them. This document is the report of that Conversation, referred to as Paciano II. The moderator was Dr Giuseppe Notarbartolo di Sciara and the Report was written by Kieran Mulvaney in consultation with all participants, and with reference to an Aide Memoire prepared by the Rapporteur, Dr Russell Leaper. The sponsor and organisers have agreed with the general sentiment expressed by participants in Paciano II that further such conversations should be held at roughly yearly intervals and they will try to satisfy that desire. Although these future gatherings would be concerned with the living ocean they would not necessarily be restricted in future to consideration of whales and whaling. Discussions are on-going for selection of a theme which is of both scientific interest and practical concern for conservation of marine life and management of the uses of ocean space. (Document has 18 pages)

Paciano II: a report of a conversation on whaling and science, 1-3 March 2008

In 2006 the UK-based charity, Global Ocean, with local support from the Third Millennium Foundation, convened a Conversation among specialists about the problems facing the conservation of whales. Called "A consultation on whaling", this gathering was held in the ancient village of Paciano, in Umbria near the border with Tuscany, 15 – 17 October 2006. There were 15 participants from 11 countries. Dr Kees Lankester served as moderator. The outcome was an Aide Memoire which served to guide the participants in the run-up to the 2007 meeting of the International Whaling Commission (IWC), held in Anchorage, Alaska, in June. One point of agreement was that a second consultation should be held in the months following the Anchorage meeting, involving some but not necessarily all of the participants in the first, but concentrating this time on scientific issues – especially those encountered in the Scientific Committee of the IWC –with particular attention to informing a wider public about those scientific activities in relation to the problems confronting the IWC and the views of scientists about them. This document is the report of that Conversation, referred to as Paciano II. The moderator was Dr Giuseppe Notarbartolo di Sciara and the Report was written by Kieran Mulvaney in consultation with all participants, and with reference to an Aide Memoire prepared by the Rapporteur, Dr Russell Leaper. The sponsor and organisers have agreed with the general sentiment expressed by participants in Paciano II that further such conversations should be held at roughly yearly intervals and they will try to satisfy that desire. Although these future gatherings would be concerned with the living ocean they would not necessarily be restricted in future to consideration of whales and whaling. Discussions are on-going for selection of a theme which is of both scientific interest and practical concern for conservation of marine life and management of the uses of ocean space. (19 page document)

Ichthyological ecoregions of Argentina

The Argentine Republic is situated in the southernmost portion of the American continent, occupying over 2,785,600 km2 not including the Antarctic territory. The country ranges from subtropical areas (21º46’S) to subantarctic regions (55º03’S), extending latitudinally over about 4,000 km. It possesses significant latitudinal and altitudinal variation (33º of latitudinal range, and heights from Bajo de San Julián in Santa Cruz province at 105 m below sea level, up to Mt. Aconcagua, 6,959 m over sea level), as well as two gradients of physical variability, extending in north-south and east-west directions. Owing to these features, the country presents a wide range of climates and soil types, being one of the countries with greatest diversity of biogeographical units (Lean et al., 1990, In: Bertonatti & Corcuera, 2000). There are four main hydrographic systems: Río de la Plata basin, the Atlantic and Pacific drainages, and several endorrheic systems. Within these basins, the ichthyofaunistic assemblage is well represented, with different magnitude in accordance with the different taxonomic groupings and regions considered. From an ichthyogeographic standpoint, and according to the works of Ringuelet (1975) and Arratia et al. (1983), Argentina is included in the Brasilic and Austral Subregions. The first of these is represented by two domains: the Andean Domain, comprising the southernmost portion of Titicaca Province, and the Paranensean Domain, including part of Alto Paraná and Paranoplatensean Provinces. The Austral Subregion is represented in Argentina by the Subandean-Cuyan and Patagonian Provinces. The present survey indicates that there are about 441 fish species in Argentina, distributed throughout the country; this number represents less than 10% of the total fish species occurring in the Neotropical Region. There is a recognizable trend of faunal impoverishment, both in North-South and East-West direction, reaching its maximum expression in the provinces of Tierra del Fuego (situated at approximately 52º30’S to 55ºS, and 65ºS to 68º50’W) and San Juan (approximately 28º50’S and 67ºW to 70º45’W), which have 4 and 5 fish species respectively. In north-south direction, one of the regional indicators of this phenomenon is the Salado river basin in Buenos Aires province, which constitutes the southern distributional boundary for the majority of the paranoplatensean ichthyofauna; 12 of the families occurring in the Paraná-Plata system are absent from this pauperized paranensean ichthyofaunal assemblage. Most of the continental fish fauna of Argentina belongs to the primary division of Myers (1949), while some elements are included in the secondary division and others in an amphibiotic or ‘marine penetration’ category. This ichthyofaunistic scope encompasses a wide range of morphological, biological, ecological and ethological types (benthic and pelagic, migrating and sedentary, haematophagous or parasites, annual species, inhabitants of plains or heights, estivation-adapted, etc.) inhabiting different regions within the national territory.

Comparison of Torpedograss and Pickerelweed Susceptibility to Glyphosate

Torpedograss (Panicum repens L.) is one of the most invasive exotic plants in aquatic systems. Repeat applications of (N-phosphonomethyl) glycine (glyphosate) herbicides provide limited control of torpedograss; unfortunately, glyphosate often negatively impacts most non-target native species that grow alongside the weed. This experiment studied the effect of glyphosate on pickerelweed (Pontederia cordata L.), a native plant that shares habitats with torpedograss. Actively growing plants of torpedograss and pickerelweed were cultured in 8-liter containers and sprayed to wet with one of four rates of glyphosate: 0%, 0.75%, 1.0%, or 1.5%. Each treatment included a surfactant to aid in herbicide uptake and a surface dye to verify uniform application of the treatments. All herbicide treatments were applied with a backpack sprayer to intact plants and to cut stubble of both species. Four replicates were treated for each species-rategrowth combination during each of two experiment periods. Plant dry weights 8 weeks after herbicide application suggest that torpedograss was effectively controlled by the highest rate of glyphosate applied to cut stubble. Pickerelweed was unaffected when the highest rate of glyphosate was applied as a cut-and-spray treatment. These data suggest that a cut-and-spray application of a 1.5% solution of glyphosate may be an effective strategy to control torpedograss without deleteriously affecting pickerelweed. (PDF contains 4 pages.)

El Herbario: significado, valor y uso.

En la historia de la vida sobre la Tierra, el capítulo que trata sobre el almacenamiento y conservación de las plantas se escribe en los dominios del herbario. El herbario posee los ejemplares que documentan la exploración del hombre sobre la superficie terrestre, de manera que no sólo existe el documento escrito que narra la historia del explorador sino que tenemos el privilegio de tocar esos objetos o especímenes. Así, cada herbario en el mundo posee un tesoro escondido de especímenes históricos que son el fiel testigo de las hazañas de un investigador o de una exploración a algún lugar remoto. En las últimas dos décadas el medio en el que se desarrollan los herbarios y sus colecciones han subrido cambios muy significativos, los que a su vez han ejercido presiones sobre quienes manejan las colecciones. Algunos de estos cambios son la disminución de los aportes económicos a los herbarios, el cambio en el uso de la evidencia morfológica hacia la molecular en los estudios sistemáticos y la pérdida acelerada de la biodiversidad que trae aparejada la necesidad urgente de realizar inventarios florísticos. En una era de extinción de biotas, las colecciones valiosas como son hoy día, serán aún más valiosas en los años por venir. Las colecciones representan el testigo imprescindible para la ciencia y el vehículo para llegar a las posibles soluciones. Es por ello que el conocimiento del significado, valor y uso del herbario y sus colecciones reviste una vital importancia para la ciencia y para la sociedad.

Vertebrates Removed by Mechanical Weed Harvesting in Lake Keesus, Wisconsin

Mechanical weed harvesting has been used to control nuisance vegetation in Lake Keesus since 1979. Fish, turtles, and amphibians often become entangled in the vegetation and are incidentally removed from the lake while harvesting weeds. Mechanical harvesting removed 2 to 8% of the standing crop of juvenile fish in harvested areas in Saratoga Lake, New York (Mikol 1985) and 32% of the fish population in harvested areas in Orange Lake, Florida, representing an estimated replacement value of $6000 per ha (Haller et al. 19890). Engle (1990) found mechanical harvesting removed 21,000 to 31,000 fish per year from Lake Halverson, Wisconsin, representing 25% of the fry in the lake. Little other current information has been published concerning aquatic vertebrate removal by mechanical weed harvesting in Wisconsin, though it is a commonly used management tool. Additionally, only Engle (1990) reported information on the removal of turtles relative to weed harvesting, but none on amphibians. The objective of this study was to document the number, species, and size of vertebrates removed by mechanically harvesting weeds in Lake Keesus.

Compatibility of Glyphosate with Galerucella calmariensis; a Biological Control Agent for Purple Loosestrife (Lythrum salicaria)

By integrating Galerucella calmariensis with glyphosate there is potential to achieve both immediate and sustained control of purple loosestrife (Lythrum salicaria). The objective of this study was to determine the compatibility of glyphosate on the oviposition and survival of adult G. Calmariensis and on the ability of G. calmariensis third instar larvae to pupate to teneral adults. Our results revealed glyphosate (formulated as Roundup) at a concentration of 2% (2.43L/acre) and 4% solution (4.86 L/acre) had no impact on the ability of G. calmariensis third instar larvae to pupate to new generation adults. To examine the effect of a 2% solution of glyphosate on adult G. calmariensis oviposition and survival, adults were randomly divided between a direct contact group (adults sprayed directly), an indirect contact group (host plants with adults were sprayed), and a control group. Our results revealed that glyphosate does not impact G. calmariensis oviposition or adult survival. The results of this study indicate that G. calmariensis is compatible with glyphosate indicating that further field studies examining integrated control strategies for purple loosestrife are warranted.

The Rise and Fall of Water Net (Hydrodictyon reticulatum) in New Zealand

During the late 1980s to early 1990s a range of aquatic habitats in the central North Island of New Zealand were invaded by the filamentous green alga, water net Hydrodictyon reticulatum (Linn. Lagerheim). The alga caused significant economic and recreational impacts at major sites of infestation, but it was also associated with enhanced invertebrate numbers and was the likely cause of an improvement in the trout fishery. The causes of prolific growth of water net and the range of control options pursued are reviewed. The possible causes of its sudden decline in 1995 are considered, including physical factors, increase in grazer pressure, disease, and loss of genetic vigour.

Laboratory Evaluation of Mefluidide Effects on Elongation of Hydrilla and Eurasian Watermilfoil

The potential of mefluidide (N-(2,4-dimethyl-5[[trifluromethyl) sulfonyl] amino] phenol) acetamide) to act as a submersed aquatic plant growth regulator was evaluated using a laboratory bioassay system. Main stem elongation of hydrilla (Hydrilla verticillata (L.f.) Royle) and Eurasian watermilfoil (Myriophyllum spicatum L.) was effectively reduced by mefluidide at low concentrations. The lowest effective concentration of mefluidide that reduced stem length in Eurasian watermilfoil (100 yg a.i./L) was 5 times lower than that for hydrilla (500 yg a.i./L). Short-term net photosynthetic rates of these plants were not affected by mefluidide at concentrations as high as 1000 yg a.i./L. The minimum exposure time required to maintain an inhibitory effect for at least 28 days at a concentration of 500 yg ai.i./L was 3 to 7 days for Eurasian watermilfoil and 7 to 14 days for hydrilla. The results suggest that mefluidide is a more effective growth regulator for Eurasian watermilfoil than hydrilla. Exogenously applied gibberellic acid (GA) did not completely overcome the inhibitory effect of mefluidide even when GA was added at a high concentration (10-5 M). In addition, the internodal lengths of stems treated with mefluidide were not reduced as they were when treated with gibberellin synthesis inhibitors. The reduction of main stem elongation by mefluidide appeared to be due to the inhibition of new cell and tissue development at the stem tip rather than from inhibition of GA biosynthesis.

Seasonal Changes in Chemical Composition of Eurasion Watermilfoil (Myriophyllum spicatum L.) and Water Temperature at Two Sites in northern California: implications for Herbivory

We compared seasonal changes in Eurasian watermilfoil (Myriophyllum spicatum L.) characteristics and water temperature for a shallow poind in Davis, CA, and the Truckee River, near Tahoe City, CA. Tissue C and N were 15% lower in plants from the Truckee River than in plants from the Davis pond. Seasonal fluctuations in tissue N were also different. Mean phenolic acid content of Truckee River palnts (162yM g-1) was less than those from the shallow pond (195 yM g-1). Phenolic acid content was positively related to tissue C for Truckee River and Davis pond plants and, tissue C:N ratio for Truckee River plants. Mean monthly water temperature (1990 to 1998) for the Truckee River site was less than 20 C. Water temperatures were warmer in August and September at this site. However, Eurasian watermilfoil collected during these months was characterized by lower levels of tissue N. During a 29-month period beginning January 1994, mean monthly water temperature for the Davis pond exceeded 20 C, only during July to September 1995. Tissue N was generally greater during summer for watermilfoil growing in the pond. These results imply that Eurasian watermilfoil biological control agents may have different developmental rates in these habitats, and thus different impacts on watermilfoil populations.

Common Coastal Plants in Florida: a guide to planting and maintenance

(PDF has 125 pages.)

Wilmington gray to blue

Wilmington is situated on the divide of two major watersheds, the Cape Fear River and the Atlantic Intracoastal Waterway. All surface waters in Wilmington drain to one of these two water bodies and are divided into two groups: tidal creeks and Cape Fear River tributaries. Cape Fear River tributaries drain directly to the Cape Fear River and comprise the western portion of Wilmington’s surface waters. Tidal creeks drain directly into the Atlantic Intracoastal Waterway and make up the eastern portion of Wilmington’s surface waters. (PDF contains 4 pages)

The decline of migratory salmonid stocks: a new threat to pearl mussels in Scotland

The general decline of the endangered freshwater pearl mussel Margaritifera margaritifera (L.) throughout its holarctic range is well documented. Scotland is considered to be a stronghold of margaritifera, containing approximately half of the world's known remaining viable populations. However, even here the majority of populations have declined and many have disappeared completely. This article provides an overview of the freshwater pearl mussel life-cycle and the life-cycle of salmonids which are the host fish during the freshwater mussels short parasitic larval phase. The authors highlight the potential implications of the decline of salmonids for freshwater populations in Scotland.