Posts Tagged ‘conservation’

Peacock Bass Science and Conservation – Peacock Bass pH Tolerance

September 16, 2011
The more anglers know about their quarry, the better they are able to successfully pursue it and manage its conservation. The giant peacock bass (Cichla temensis) roams a blackwater environment that is so significantly different from that of temperate zone freshwater sportfish, that it is worthwhile for peacock bass anglers visiting the Amazon to gain an understanding of the peacock’s home waters. The following article attempts to provide some insights via a research project assessing fishes’ acid tolerance in blackwater environments Throughout North America, Europe and Asia, pollution has caused serious damage to aquatic ecosystems. One of the worst culprits is acid rain. Resulting mostly from sulfur emitted by power plant smokestacks, this toxic acidification has been shown to cause massive fish kills and a serious loss of biodiversity in our lakes, rivers and streams.
On the other hand, in the Amazon basin, highly acidic “blackwater” regions exist that support a huge diversity of fishes in spite of being far more acidic than even our most damaged waters. In fact, this is the preferred home of the giant peacock bass. The most powerful freshwater gamefish in the world, lives in water with enough acid content to kill most species! The obvious question you might ask is, “How is this possible?” Many researchers have asked the same question. The answer may lie in the tea-colored material that gives blackwater its name.

Blackwater is formed when wet, oxygen-poor soils permit the slow decay of matter from vascular plant material. Runoff delivers a constant supply of this mixture of dissolved organic matter (mostly made up of tannic and humic acids). Not only does this material deliver blackwater’s characteristic coloration, but scientists have found convincing evidence that it actually protects fishes against the poisonous effects of acidic environments.

Acid water causes fishes to lose their body salts. Freshwater species have a biological pumping system in the cells of their gills that keeps the salt in their bodies from leaking out into the salt-free freshwater that surrounds them. Acid conditions attack these cells and cause them to stop working. The material in blackwater, however, appears to provide a protective effect for these cells, enabling them to continue to work normally. The peacock’s own ecosystem may be what protects it from environmental toxicity that kills fish elsewhere.

The Amazon is a giant enigma, with thousands of interlocking puzzles waiting to be solved. We haven’t even begun to understand how they fit together. Here is just one more reason why it must be protected at all costs. With more study, we might learn how to use Amazon-based knowledge to protect fishes in each of our various backyards. Perhaps we’ll find that reducing the constant deforestation in our countryside might put more of these blackwater materials into our waters and help slow the rate of environmental degradation and fish loss.

Note – The following unpublished paper is the result of an experiment performed on non-Amazon fishes, with an eye toward understanding more about the nature of Amazon Blackwater systems. The reference materials cited in this paper can provide additional information regarding this subject matter from peer-reviewed sources.

Laboratory Analysis of the Effects of Blackwater on Low pH Tolerance in Fishes

PAUL REISS; Rutgers University, Graduate Program in Ecology and Evolution, New Brunswick, NJ, 08901, USA
Rutgers University Marine Field Station, Tuckerton, NJ

Abstract

The unusually high level of fish biodiversity found in acidic “blackwater” systems in the Amazon basin suggests that the humic and fulvic acids in blackwater may provide some form of protection against the toxic effects of low pH, or that fishes endemic to this environment may be more tolerant of those effects. These ideas were tested by two experiments in a laboratory study. In the first experiment, seven fish species from three water types were subjected to a treatment regime of reduced pH to compare the species’ tolerance to pH toxicity. Species examined included: Enneacanthus obesus, Micropterus salmoides and Aphredoderus sayanus from blackwater; Fundulus heteroclitus, Menidia menidia and Cyprinodon variegatus from brackish water and Lepomis macrochirus from clear freshwater. The results demonstrated markedly different resistance to mortality in low pH among the species, as measured by the cumulative concentration of excess H+ ion over time. For example, Enneacanthus was able to tolerate almost three times as much exposure as Lepomis, a member of the same family, and over eight times the exposure of Cyprinodon, a brackish water fish. The results also demonstrated that fishes from blackwater are more resistant to low pH toxicity, as a group, than fishes from other source waters.

In a second experiment, the effect of water type on tolerance to low pH was measured among a subset of species selected from the first experiment, i.e., Fundulus heteroclitus, Cyprinodon variegatus and Lepomis macrochirus. Resistance to mortality ranged from 20% to 100% greater in both blackwater and brackish water than in clear freshwater for each species. These results indicate that there are effects inherent in both blackwater and brackish water that protect fishes against low pH and which are lacking in clear freshwater. The study examines the physiological aspects of pH toxicity in various water types, considers differences in innate or acquired tolerance to low pH among species and analyzes the relevance of ecosystem management strategies in relation to the toxic effects of acidification.

To read the full report, please click here.

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Implementation Techniques for an Optimized Catch and Release Sport Fishery as a Tool for Sustainable Harvest

June 9, 2011

By Paul Reiss

(Complete Study: http://www.acuteangling.com/Reference/C&RProposal.html)

Introduction

Catch and release fishing has been demonstrated to be an extremely effective aquatic conservation and environmental protection mechanism. Widely used as a tool for the preservation of fish fauna, catch and release has been studied in great detail for nearly a half century. Shown to be more environmentally effective than the simple closing of aquatic areas, catch and release fishing is used in most environmentally advanced societies (1).

Aquatic fauna in any region, whether or not man is present, vary in population success over time, primarily due to a range of external factors and conditions. Natural factors define a fishery’s capacity to support fish of all types, for instance: Rapidly variable weather and water level changes directly affect the fish’s survival medium. Food supply and predation create an additional impact, typically cyclically raising and lowering specific species populations. Migratory behavior causes exposure to varied water types, conditions and hazards. Man, with his attendant environmental effects, such as commercial fish harvesting and pollution (water quality) can act as significant modifiers to these natural variables and incrementally affect the natural capacity of a fishery.

With few exceptions, in an unrestrained or undammed river system, man is unable to control natural factors. Therefore, uncontrollable natural conditions will continue to be primary defining factors of a fishery’s overall characteristics and capacities. Man’s artificial impact, whether minimal or extremely adverse, can, however, be controlled. Where an area is subject to significant human impact because of uncontrolled poaching, substantial improvements can be made by the introduction of low impact catch and release fishing programs. Increased surveillance of the river by catch and release fishermen can lead to significant reductions in poaching. Further, sport fishing produces regional economic benefits, resulting in greater community stewardship of the aquatic resources by the local population. Human impact can be made decidedly positive by substituting an intelligent program of non-consumptive, catch and release fishing (a form of sustainable harvest) for pre-existing, uncontrolled, haphazard exploitation.

This paper discusses the positive effects and applicability of the concept of catch and release fishing, using carefully selected techniques appropriate for the natural conditions and species make-up of a region. By using techniques that assure minimal environmental impact and very low mortality on fish fauna, sport fishing, with its associated tourism, can significantly increase the economic benefit to a region while simultaneously decreasing the incidence and negative impact of commercial fishing, poaching and meat hunting (100% mortality). A properly implemented program of catch and release sport fishing can create a human accessible fishery maintained in a natural state, protected by the alternative economic benefits brought to what might otherwise be an adversely impacting regional human population.

Specifically, this paper analyzes the potential environmental and economic benefits of applying a program of catch and release fishing on remote river systems on the fringe of the Amazon basin. Observations were made on a highlands river in the northern fringe of the Amazon basin to assess the sport fishing potential of the waters of the region. The species present, their sport fishing characteristics, spawning activities and the present effects of human activity were examined. These findings led to an analysis of the scientific literature available for the purpose of assessing potential catch and release mortality. Those results demonstrate that a catch and release program designed specifically for the observed fishery would create minimal environmental impact. (See the related paper, “Catch and Release Effectiveness and Mortality“.)

Observations of the result of implementing controlled catch and release fishing programs elsewhere in the Amazon basin show that such activities have resulted in the reduction of preexisting negative impacts on the environment and have created net environmental benefits. (See the related paper, “Observations of the Effects of Catch and Release Fishing in the Amazon Basin“.) Simultaneously, significant economic benefits have been observed in the regions involved as a result of controlled, selective, sport fishing tourism activity.

Understanding the environmental importance of Amazon fringe forest/savannah environments as a protective buffer zone of the Amazon basin as a whole and recognizing the value of the existing research performed in these unique ecosystems, as well as the future research potential, puts the necessity of protecting these regions into stark relief. The implementation of specifically designed catch and release sport fishing programs offers the potential of enhancing the protection of these regions as well as creating additional research opportunities relating to the regions’ aquatic resources.

To read the complete study, please click here.

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Sign the Earth Day Petition

April 17, 2011

From The Nature Conservancy, a wonderful organization whose mission is to preserve the plants, animals and natural communities that represent the diversity of life on Earth by protecting the lands and waters they need to survive:

About this Petition:

Sign this petition to encourage others and join us as we celebrate the planet we live on, the food it provides and the people we share it with. Picnic for the Planet will be the world’s largest virtual picnic – and you are invited! Choose a favorite outdoor location, round up some friends and take the planet out to lunch! http://earthday.nature.org

The Desired Outcome of this Petition:

To protect the lands and waters we rely on for survival…for our food. One of the most direct ways you can help achieve this outcome is by changing your individual impact on the planet through simple actions like eating more sustainably and greening your diet.

Sign the Earth Day Petition

Meanwhile, here’s a big Pirapitinga caught on an Acute Angling trip for your Sunday viewing pleasure:

Pirapitinga

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Take Me Fishing

April 13, 2011

Classic commercial part of the “Take Me Fishing” campaign, which encourages participation in recreational boating and fishing as well as generates awareness about the conservation of natural aquatic resources.

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