Fish of the Week: Catfish – Sorubim

September 26, 2011
Sorubim

Sorubim

Our “Fish of the Week” is Catfish – Sorubim, which is a beautiful species sporting an elegant pattern of hieroglyphic black markings on a silver grey background dorsally and stark white ventrally. The common name sorubim is used for several similarly shaped species in the genus. Body markings, typical habitat and maximum size differ. P. tigrinum is commonly encountered by anglers in Amazon lowland, highland and Guyana shield fisheries.

The Sorubim is distinguished by its flattened head, elongate body and large terminal mouth. Its silvery gray upper body with heiroglyphic markings dorsally, and tiger stripes laterally, also set it apart. Sorubim’s fin markings continue from the body, evolving into spots toward margins. The silver gray on its dorsum changes abruptly to white on its ventral sides, as well as its abdomen. Specimens up to one meter in length and more than 100 pounds have been reported. The genus contains eight recognised species, and although all are similarly elongate, many are uniquely marked and have separate ranges. Common names include Barred Shovelnose (English); sorubim, suribim, cachara (local); and Bagre rayado.

This catfish can be found in Brazil, Peru, Guyana, Ecuador, Bolivia, Suriname, Columbia, Venezuela and Argentina, particularly in the Amazon, Orinoco, Essequibo, Corantijn and Parana drainages and river basins. They usually occupy lotic (moving water) environments in blackwater river systems. Primarily feeding on fishes, P. fasciatumis are readily encountered with cut bait on shallow sandbars in river channels. Although mostly an evening and nocturnal feeder, anglers are often surprised by large sorubim attacking artificial lures in open water at any time of day. The current IGFA record is 35 pounds, 10 ounces.

In addition to being a great angler’s target, the barred sorubim is a pleasant adjunct to any fishery. Its habit of attacking artificial lures and then fighting like whiskered tuna, makes it endearing to peacock bass anglers and catfishermen alike. In most high gradient fisheries sorubim can be targeted by anglers at evening time. They tend to congregate and forage at the edges of shallow beaches with nearby drop-offs to deeper water. Small live bait or pieces of cut bait are equally effective when cast onto the beach and allowed to drift naturally to the nearby drop-off. An effective rig consists of a 10/0 to 14/0 circle hook (or smaller J hook) with a wire leader and relatively light sinker (approx. 1 oz.), enough to keep it down while still allowing the current to slowly carry it. The take is usually quite forceful. Once hooked, sorubim will fight in open water with strong runs and surprising stamina.

Pintado

Pintado

Pintado - Psuedoplatystoma corruscans - up to 1.5 meter
This larger catfish is found outside the Amazon in the Pantanal and the Sao Francisco and Parana river basins
(Illustration from “Peixes do Pantanal” – Embrapa – poster)

Pintado

Pintado

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The Amazon Sky

September 23, 2011

The beautiful Amazon sky

 

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Jenny Schools “The Fish Finder!”

September 22, 2011

World champion peacock bass angler Steve Townson joins Jenny Reiss of Acute Angling on a Blackwater Explorer trip. In this episode Steve gives Jenny some pointers on peacock bass fishing and Jenny thanks him by catching the bigger fish. To learn more about peacock bass fishing, visit http://www.acuteangling.com.

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Fall Trips Still Available But Going Fast!

September 21, 2011

We have several exotic fishing trips still available for the fall. Space is limited and they’re going fast, so make sure you schedule the fishing trip of a lifetime before they’re sold out! You can do so by visiting our interactive trip finder.

(This could be you!)

(This could be you!)

 

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Photo – Elaine Riedel Conquers an Enormous Red-Tailed Catfish

September 20, 2011

Elaine Riedel conquered this enormous red-tailed catfish (Pirarara) on our Fall Fly-in Safari trip to the Rio Unini.

Elaine Riedel With an Enormous Red-Tailed Catfish

Elaine Riedel With an Enormous Red-Tailed Catfish

 

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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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Connect With Us On Social Media!

September 14, 2011

You can now stay up to date with Acute Angling and everything exotic fishing through the following channels:

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Whatever your preferred network, we encourage you to get involved and join the conversation as we bring you news, facts, articles, photos, videos and more!

Photo – Ron Kiley With A Beauty

September 13, 2011

Ron Kiley caught this beauty on a backwater of the Rio Matupiri on a Fall Yacht trip.

Ron Kiley - Peacock Bass

Ron Kiley - Peacock Bass

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Fish of the Week: Payara – Hydrolycus scomberoides

September 12, 2011
Hydrolycus scomberoides

Hydrolycus scomberoides

Our “Fish of the Week” is Payara – Hydrolycus scomberoides, which is readily distinguished from its congeners by three features: It possesses serrations on the exposed portion of its scales; It has a small black spot on the base of the innermost pectoral fin ray; The base of the pelvic fin is dorsal of the ventral profile of the body.

The key to identifying a Hydrolycus scomberoides is its silvery, elongate body, as well as the unique black spot on pectoral fin base. It also has a dark blotch above the pectoral fin. Its adipose fin also has a dark pigmentation. Hydrolycus scomberoides also is mostly silvery, darker dorsally, with dark pigmentation on anal and caudal fins. This fish features a black spot on its pectoral fin and has 93-106 lateral line scales. Museum specimans have been measured up to 300 mm.

Similar to Hydrolycus armatus, this fish can be found in Brazil, Peru, Ecuador, Bolivia and Venezuela, particularly in the river basins of the Amazon, above Tapajos and Rio Apure drainages.

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Lures Everywhere!

September 9, 2011

Check out some of these lures! What type of tackle is your favorite to fish with?

Lures

Lures

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