Species Accounts
Sciaenidae - Drums and Croakers - Tambours
Drums or croakers are found in the Atlantic, Indian and Pacific oceans and some species are permanent residents of freshwater. There are about 270 species with 3 species on Canada's Pacific coast, 2 on the Atlantic coast, and 1 in freshwater Arctic and Atlantic drainages.
These fishes have long dorsal fins with a short section having 6-16 spines separated by a deep notch or gap from 1 spine and 20-35 soft rays. The anal fin has only 1-2 spines and 6-13 soft rays. The tail fin is deeply forked. The mouth is usually on the lower side of a rounded head. Jaw teeth are small but some species have massive throat teeth for crushing molluscs and crustaceans. The lateral line scales run to the tip of the caudal fin. Scales are cycloid or ctenoid and cover the head and body. The chin may have small barbels or conspicuous pores and slits. The head has large canals as part of the lateral line system. The upper edge of the opercle bone is forked, with a bony flap over the gill cover. The swimbladder is complex often with many twig-like or finger-like branches; some have been likened to a carrot, others are hammer or anchor-shaped. The sagittal otolith is very large in many species.
Drums are common shallow water species in warmer areas of the world around estuaries, in bays and on banks. Some are found as deep as 600 m. Freshwater species are common in South America but there is only one such species in North America. The swim bladder is used as a "drum" or resonating chamber to produce sound by the action of the drumming muscles. The sounds include quacks, tapping, grunting and snoring as well as drumming and croaking. These noises were understandably a source of confusion to the first sonar operators. Sounds made by Japanese submarines before the Pearl Harbour attack were thought to be drums. The sounds are used in courtship by males. Some species without swimbladders grind their throat teeth to make sounds. The large sagittal otolith or earstone of one of the inner ear canals has been used as jewelry and a good luck charm. Scales are also used to make jewelry. Some drums are used in aquarium displays. They are popular sport fish and are excellent food fish.
Freshwater Drum / Malachigan
Aplodinotus grunniens Rafinesque, 1819
Taxonomy
Other common names include Sheepshead, Silver Bass, Grunter, Red River Bass, Thunder-pumper, White Perch, Goo, Gray Perch, Lake Drum, River Drum, Jewel-head, Bubbler, Grinder, Crocus, Achigan blanc and Gaspergou. "Gaspergou" or casburgot from "casser" (to break) and "burgeau" (a kind of shellfish) is a Cajun word.
Key Characters
This is the only freshwater species of this family in Canada. The massive second anal fin spine and lateral line running to the end of the tail are diagnostic.
Description
The first dorsal fin has 8-10 spines, the second dorsal fin with 1 spine and 24-33 soft rays. The anal fin has 2 spines and 7-8 branched rays. The lateral line to the tail base has 48-53 scales. Short gill rakers number 19-21.
Colour
The back is dark green to olive-brown, bronze or silvery-bluish. Flanks are silvery to bluish or purplish and the belly is white. Fins are dusky except for white to cream or orange-tinged pelvics and clear pectorals. There are some reports of fins being almost fluorescent purple.
Size
Reaches 1.2 m and 27.7 kg. The world, all-tackle angling record weighed 24.72 kg and was caught in 1972 at Nickajack Lake, Tennessee. A 9.35 kg fish was caught in the French River, Ontario. A 22 pound fish was caught at the base of the Rideau Falls in July 1961 (Hopkins, 1990b).
Distribution
Found from Hudson Bay south to Guatemala, but not in Atlantic coast drainages south of the St. Lawrence River basin. This is the greatest range in latitude of any North American freshwater fish. In Canada from the upper St. Lawrence River basin, Ottawa River, at Abitibi in the James Bay drainage, in the Great Lakes except for Lake Superior, in Manitoba to Hudson Bay and in southwestern Saskatchewan. This species is known mostly from the Ottawa River in the NCR and, rarely, in the Rideau River with one specimen taken between the Bank and Bronson Street bridges in 1998 (Phelps et al. (2000). It is not commonly caught in the NCR, with less than 10 fish on record before 2004, but this may be misleading as it is based on scientific collections. It is probably quite common in the Ottawa River, being regularly caught by anglers at Petrie Island for example, and it is also present in the South Nation River (personal observations, August 2004).
Origin
This species entered the NCR from a Mississippian refugium.
Habitat
The favoured habitat of this species is large and shallow waters including both lakes and rivers. Both clear and turbid water is occupied. Freshwater Drums retire to deeper waters in winter and in summer are found at less than 10 m in Lake Erie for example. Its preferred temperature is 26.5°C.
Age and Growth
Females attain larger sizes than males and grow faster after the first 5 years. Males can be mature at 2 years and all are mature at 6. Females mature 1 year later than males. Most drums in Lake Erie are 3-8 years old but they live at least 17 years.
Food
Food is insects, crustaceans such as crayfish, molluscs and fish. River populations are said to favour clams and snails, which are crushed by the large molariform throat teeth, but molluscs are not as significant a part of the diet as might be expected from the specialised throat teeth. However, the exotic zebra mussels are eaten by drums which may help control this pest. The young eat crustaceans and aquatic insects.
Reproduction
Spawning occurs from June to September in southern Canada but comparatively little is known about it. It may take place over sand or mud in shallows or in open water far from shore. Temperatures in mid- to late June are 20-23°C in Manitoba when mature fish are found. Courtship is accompanied by the drumming sounds of the males, especially in the evening, and has been likened to the sound of rumbling traffic at a distance. Up to 686,000 eggs of 1.7 mm diameter are found in each female. Eggs float to the surface, an unusual feature in freshwater Canadian freshwater fishes.
Importance
An angler catch of 129,327 drums was made in Ontario waters of Lake Erie from June to August 1978. It is also a commercially important species and is marketed as "white perch". Over half a million kg have been caught annually from Lake Erie in Canadian waters. Small (1883) and Small and Lett (1884; 1885) noted that this species had been abundant on Ottawa markets, had declined and was again increasing. The flesh is firm and flavourful and is delicious when smoked. The Ontario Ministry of Natural Resources publishes a print and on-line "Guide to Eating Ontario Sport Fish" (www.mnr.gov.on.ca/MNR/) and has advisory limits for eating this species in the South Nation River. As these limits are apt to change, anglers consuming this fish should consult the most recent version.
This species is the only known host for the glochidia (= larvae) of the Pink Heelsplitter, a freshwater mussel (Potamilus alatus)(A. Martel, personal communication, 2002).
© Brian W. Coad (www.briancoad.com)