List of Amistad Lake Fish Species
Amistad Lake is a reservoir on the Rio Grande River, with regions in both Texas and Mexico. The US portion of the reservoir comprises the Amistad National Recreation Area. The waters in Lake Amistad are normally fairly clear, and the lake is deep, reaching a maximum of 217 feet. The substrate is rocky in most parts, with a combination of steep drop-offs and more gradual shorelines.
The vegetation profile depends on the water level, which has been known to fluctuate dramatically in the past. As well as being an important recreational resource, Amistad Reservoir is utilized for irrigation and the generation of electricity.
Amistad Lake experiences problems with quagga mussels. The draining and checking of boats is required before they are moved to a different reservoir to help prevent the spread of this ecologically damaging, invasive species.
List of Fish Species in Amistad Lake
1) Largemouth bass (Micropterus salmoides)
The largemouth bass is a popular game fish that has been introduced to a wide variety of places across the world. It is a large fish, with a maximum length of 97 cm (38 in), although it is more commonly found at lengths of approximately 40 cm (16 in). Although this species tends to prefer muddy or sandy substrate, it is fairly adaptable and has thrived in Amistad Lake despite the rocky environment.
Largemouth bass are occasionally cannibalistic but also feed on other fish species, crayfish, and frogs. Juvenile largemouth bass consume a slightly smaller diet of crustaceans and insects. During spawning, this species ceases feeding, and the male becomes more aggressive as he builds and guards his nest. Females may visit numerous nests, and it is the males that remain with the fertilized eggs for a month after spawning, to provide care in the form of fanning and protection from predation.
This species is reported to be one of the most exciting to catch – they are aggressive fish and will put up a decent fight, sometimes even leaping out of the water. The best times to fish for largemouth bass in Lake Amistad are through the fall, winter, and spring.
2) Smallmouth bass (Micropterus dolomieu)
Smallmouth bass can attain maximum lengths of around 70 cm (28 in), although similar to the largemouth bass, they are usually found to be much smaller, typically just 25 cm (10 in). They have a preference for shallow waters, so are well suited to the rocky shorelines of Amistad Lake. Juveniles consume plankton and aquatic insects, progressing to a diet of crayfish, larger insects, and even cannibalizing other smallmouth bass. In turn, smallmouth bass are also predated on by larger fish species and turtles.
Smallmouth bass return to the same area each year to build their nests and spawn. As in the largemouth bass, the female may visit several nests, while the male remains to guard and care for the eggs.
The popularity of smallmouth bass as a game fish has risen over recent years: similar to the largemouth bass, they are a highly aggressive species and can reach trophy sizes. The best time to catch smallmouth bass is typically through the spring and summer.
3) White bass (Morone chrysops)
The white bass can reach maximum lengths of 45 cm (18 in). It prefers shallower waters, rarely venturing below 14 m (46 feet). Juveniles consume small invertebrates, such as copepods and midge larvae, and once they reach maturity they transition to a diet of shad and juvenile sunfish.
White bass are abundant throughout Amistad Lake – interestingly, reservoirs have been found to contain more white bass than natural lakes do. The best time to fish for white bass in Amistad Reservoir is between late January and March: this is the time at which they spawn, and the fish congregate at the shoreline to lay their eggs. Once spawning is complete, the fish return to deeper waters.
As well as playing an important role in the ecosystem, both as predator and prey, white bass are gaining popularity as a game fish, due to their fighting nature once hooked.
4) Striped bass (Morone saxatilis)
Striped bass are incredibly popular game fish due to their size, with some individuals reaching trophy proportions – this species has a maximum length of 200 cm (79 in)! As well as being pursued by humans, the striped bass may be picked off by osprey, which are abundant in the Amistad National Recreation Area.
The striped bass itself is a fierce predator, with adults tackling a variety of prey including herring, eels, squid, and crabs. Juveniles tend to consume a slightly less ambitious diet of shrimp, annelid worms, and insects. It has been found that the size of the prey tackled by striped bass is related to the individual’s mouth gape, presumably so that the fish doesn’t bite off more than it can chew!
Due to its popularity, there are various regulations surrounding the fishing of striped bass, to ensure that fisheries are run sustainably. For example, fishing rates have been reduced to aid the growth of populations, and habitat damage is minimized when fishing for striped bass by using gill nets or hook and line gear.
5) Channel catfish (Ictalurus punctatus)
Channel catfish are abundant throughout Amistad Reservoir. These fish can reach a maximum length of 132 cm (52 in) and are typically a blue-grey color with a white belly, although older males may be much darker.
With a preference for sandy or rocky substrate and deep, clean water, channel catfish thrive in Amistad Lake, where they consume a varied diet of small fishes, crustaceans, clams, snails, and even small mammals. Both the male and the female contribute to the building of the nest during spawning, which takes place between April and July. Once the eggs are laid, the male guards and cares for them alone.
As well as being popular game fish, they are also commonly seen in aquariums. They contribute enormous recreational and economic benefits to the local area, with many people journeying to fish for them on Amistad Lake.
6) Blue catfish (Ictalurus furcatus)
Blue catfish are morphologically very similar to channel catfish, although they do show some differences, such as having a greater maximum length of 165 cm (65 in). Another way the two species can be distinguished from one another is that the blue catfish has more than thirty anal rays, whereas the channel catfish has less than thirty. On the fly, it can be difficult to ascertain which species has been caught! As juveniles, blue catfish are silvery white, but as they age, they develop their characteristic blue color.
The blue catfish has a preference for clear waters, where it feeds on aquatic invertebrates and clams while immature, then progressing to a diet of various species of fish. Following the transition to a piscivorous diet, the growth of the blue catfish accelerates.
It is common for Ictalurus furcatus to hybridize with other catfish species, and it is thus valued for its contribution to diversifying fisheries. This species is abundant throughout Amistad Reservoir, however, it is most commonly located in areas of deep, open water.
7) Flathead catfish (Pylodictis olivaris)
Flathead catfish are only occasionally caught in Amistad Reservoir, the best time to catch them being after dark due to their nocturnal feeding habits. During the day they often hide underneath submerged logs. Despite the lower chances of finding them, people still pursue them in Lake Amistad for their trophy status, with some individuals attaining lengths of 155 cm (61 in).
Juvenile flathead catfish feed on aquatic insect larvae, while adults consume a diet of crayfish, clams, and fish. The barbels on their snouts enable them to locate their prey in low light conditions: these barbels host taste buds, allowing the catfish to taste their prey before it is even in their mouths.
This species is solitary and highly aggressive; the only exception being during spawning, which may last for several hours. Once spawning is complete however, the male then chases the female away and provides care for the eggs on his own.
8) Black crappie (Pomoxis nigromaculatus)
Black crappies prefer a muddy or sandy substrate, with clear water and plenty of vegetation to hide amongst. They will also hide by submerged logs or boulders. This species is fairly small, with a maximum length of 49 cm (19 in), and is highly social, forming schools for protection from predation.
The black crappie tends to feed in the middle of the night: small individuals consume planktonic crustaceans, whereas larger individuals may feed on small fishes. In turn, the black crappie is predated by other larger fish species, such as largemouth bass and channel catfish.
Black crappie are very similar to white crappie, but one simple way to distinguish between the two species is to count the number of spines in the dorsal fin: black crappies have seven or eight spines, whereas white crappies have just six. While coloration can be used to determine which species an individual is, the method of counting spines is much more reliable.
9) White crappie (Pomoxis annularis)
With a maximum length of 53 cm (21 in), white crappies are very similar in appearance to black crappies, although are typically paler in coloration. This species tends to prefer a muddy or sandy substrate and is tolerant of turbid waters.
Unlike black crappies, white crappies tend to feed diurnally: immature white crappies consume microcrustaceans and small insects, while adults subsist on a diet of forage fishes. Research has shown that white crappies will naturally hybridize with black crappies, although this potentially has its origins in poor water quality resulting in individuals being unable to determine the true coloration of their mate, in addition to the fact that the spawning periods of the two species overlap.
White crappies are easily caught in Amistad Lake and can be caught by a variety of different techniques. The best technique for obtaining white crappies is minnows.
10) Bluegill (Lepomis macrochirus)
Bluegills can reach maximum lengths of around 40 cm (16 in) and are generally olive-green in color with a purple sheen. The opercular flap that covers their gills is a characteristic dark blue or black, making these fish easy to identify. They prefer well-vegetated areas, where they consume a diet of snails, crayfish, insects, and worms.
This species is a member of the sunfish family and is a popular game fish despite its small size: hooked bluegills are known for their fighting spirit, which is enjoyed by many anglers. Bluegill is safe to be eaten raw, however it is reported to have a better flavor once cooked.
Following spawning, males guard the eggs for a period of seven days. However, cuckoldry is common, and many males manage to fertilize eggs and then leave the parental care to other, unwitting males.
11) Redbreast sunfish (Lepomis auritis)
Redbreast sunfish can attain maximum lengths of 30 cm (12 in), however they are more commonly found to be approximately 10 cm (4 in). They prefer either rocky or sandy substrates with plenty of vegetation, where they feed on both terrestrial and aquatic insects, including dragonflies.
Spawning tends to take place in deeper water with lower turbidity, where the male creates a depression in the substrate. The female may lay up to 1,000 eggs, following which she does not offer any form of parental care; this responsibility is left to the male. Redbreast sunfish are sensitive to environmental changes during spawning; heavily increased water flow during this time may result in nests being abandoned.
Some of the best spots to fish for redbreast sunfish include shorelines (both steep and gradual inclines), around islands or piers, and near sunken objects such as trees or boulders.
12) Tilapia (Oreochromis niloticus)
Tilapia is an invasive species that has seen great success in North America, since its introduction in the 1960s. This species has a maximum length of 60 cm (24 in) and feeds diurnally on phytoplankton and benthic algae. It is highly adaptable and can hybridize with other species of the Oreochromis genus.
Tilapia spawning is somewhat elaborate and different from the other fish found in Lake Amistad. Males fiercely defend territories that the females visit – courtship may then last several hours before spawning takes place, following which the female incubates the eggs in her mouth. She provides parental care without any input from the male.
Being an invasive species, some adverse effects of tilapia’s introduction are to be expected. Juvenile tilapia have been shown to be associated with habitat degradation, and tilapia of all ages may compete with native fish species, altering the dynamics of the ecosystem.
13) Alligator gar (Atractosteus spatula)
Alligator gars can reach enormous sizes, with maximum lengths of 300 cm (118 in). They are voracious predators, consuming crabs, turtles, waterfowl, and small mammals. Despite this, alligator gars are heavily armored against predation themselves, with tough scales complete with jagged edges to provide protection.
This species typically spawns between April and June, when water temperatures are between 20 and 30 degrees Celsius (68 to 86 degrees Fahrenheit). Spawning also tends to correlate with increases in water levels, the main reason being that this provides greater cover amongst submerged vegetation. Thus, the significant fluctuations in the water level in Lake Amistad may present problems for the alligator gar’s reproduction.
With their gigantic proportions, alligator gars can be difficult to catch. Bowfishing is a common method of harvesting alligator gars, however unlike using pole and line methods, the fish cannot be released following damage from an arrow. Declines in populations of alligator gar mean that conservation is of great concern, and maximizing re-release rates is essential to protect populations.
14) Longnose gar (Lepisosteus osseus)
The longnose gar is a popular large game fish, reaching maximum lengths of 200 cm (79 in). These fish prefer vegetated areas, where they predate fishes and crustaceans, and as in the alligator gar, are covered in tough scales that protect them from predators.
Longnose gars are an example of a living fossil – an animal that has retained primitive features and can be used to examine evolution. It has been estimated that the genus Lepisosteus has been present on earth for 180 million years. As well as providing information about primitive anatomy, gars are an excellent model species for studying embryonic development.
This species spawns between April and August, typically congregating in small groups in well-vegetated inlets. The eggs are adhesive, so clump together before sinking down to the substrate, where they remain for 3 – 9 days prior to hatching.
15) Spotted gar (Lepisosteus oculatus)
The smallest of the three gar species found in Lake Amistad, the spotted gar has a maximum length of 150 cm (59 in). It is relatively dark in color, with characteristic dark spots on its body and head. With a preference for clear waters, it predates on fish (such as bluegill) and crustaceans.
The best time to fish for spotted gars is during the spring, when they congregate in shallower waters for spawning, although they may be caught year-round in coves, around islands, and near sunken debris. Bait such as flies and minnows are recommended. While these are popular trophy fish, they are rarely eaten and are usually returned to the lake following capture.