We use great care releasing big cats and rarely take them completely out of the water. This 200 pound piraiba was safely released.
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 – 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)
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.
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.
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
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.
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.