Significance To Humans

No fishery is directed at this species, although large quantities are sometimes landed between depths of 1,300 and 1,640 ft (400 and 500 m) in the northern Gulf of Mexico. ♦

Resources

Books

Able, K. W., and M. P. Fahay. The First Year in the Life of Estuarine Fishes in the Middle Atlantic Bight. Piscataway, NJ: Rutgers University Press, 1998.

Kurlansky, M. Cod. A Biography of the Fish That Changed the World. New York: Walker and Company, 1997.

Periodicals

Bardach, J. E., and J. Case. "Sensory Capabilities of the Modified Fins of Squirrel Hake (Urophycis chuss) and Searobins (Prionotus carolinus and P. evolans)." Copeia 2 (1965): 194-206.

Beacham, T. D. "Variability in Size or Age at Sexual Maturity of White Hake, Pollock, Longfin Hake, and Silver Hake in the Canadian Maritimes Area of the Northwest Atlantic Ocean." Canadian Technical Report of Fisheries and Aquatic Sciences 1157: iv+43p.

Cohen, D. M. "Gadiformes: Overview." In Ontogeny and

Systematics of Fishes, edited by H. G. Moser, W. J. Richards, D. M. Cohen, M. P. Fahay, A. W. Kendall, Jr. and S. L. Richardson. American Society of Ichthyology and Herpetology, Special Publication no. 1 (1984): 259-265.

-, ed. "Papers on the Systematics of Gadiform Fishes."

Science Series No. 32; Los Angeles County Museum of Natural History (1989): 143-158.

Cohen, D. M., T. Inada, T. Iwamoto, and N. Scialabba. "Gadiform Fishes of the World (Order Gadiformes)." An

Annotated and Illustrated Catalogue of Cods, Hakes, Grenadiers, and Other Gadiform Fishes Known to Date. FAO Fisheries Synopsis 10, no. 125 (1990): 1-442.

Fahay, M. P. "The Ontogeny of Steindachneria argentea Goode and Bean with Comments on Its Relationships." In Papers on the Systematics of Gadiform Fishes. Science Series No. 32, edited by D. M. Cohen. Los Angeles County Museum of Natural History (1989): 143-158.

Fahay, M. P., and K. W. Able. "The White Hake, Urophycis tenuis in the Gulf of Maine: Spawning Seasonality, Habitat

Use, and Growth in Young-of-the-Year, and Relationships to the Scotian Shelf Population." Canadian Journal of Zoology 67 (1989): 1715-1724.

Fahay, M. P., and D. F. Markle. "Gadiformes: Development and Relationships." In Ontogeny and Systematics of Fishes, edited by H. G. Moser, W. J. Richards, D. M. Cohen, M. P. Fahay, A. W. Kendall, Jr., and S. L. Richardson. American Society of Ichthyplogy and Herpetology, Special Publication no. 1 (1984): 265-283.

Fahay, M. P., P. L. Berrien, D. L. Johnson, and W. W. Morse. "Essential Fish Habitat Source Document: Materials for Determining Habitat Requirements of Atlantic Cod, Gadus morhua Linnaeus." NOAA Technical Memorandum (1999) NMFS-F/NEC: 41 p.

Markle, D. F. "Identification of Larval and Juvenile Canadian Atlantic Gadoids with Comments on the Systematics of Gadid Subfamilies." Canadian Journal of Zoology 60, no. 12 (1982): 3420-3438.

Marshall, N. B., and D. M. Cohen. "Order Anacanthini (Gadiformes): Characters and Synopsis of Families."

Memoirs of the Sears Foundation for Marine Research 1, no. 6 (1973): 479-495.

Merrett, N. R. "On the Identity and Pelagic Occurrence of Larval and Juvenile Stages of Rattail Fishes (Family Macrouridae) from 60 N, 20 W, and 53 N, 20 W." Deep-Sea Research 25 (1978): 147-60.

-. "The Elusive Macrourid Alevin and Its Seeming Lack of Potential in Contributing to Intrafamilial Systematics."

In Papers on the Systematics of Gadiform Fishes. Science Series No. 32, edited by D. M. Cohen. Los Angeles County Museum of Natural History. (1989): 175-185.

Rose, G. A. "Cod Spawning on a Migration Highway in the North-west Atlantic." Nature 366 (1993):458-461.

Scott, W. B., and E. J. Crossman. "Freshwater Fishes of Canada." Fisheries Research Board of Canada Bulletin. 184 (1973): 1-966.

Michael P. Fahay

Batrachoidiformes

(Toadfshes)

Class Actinopterygii Order Batrachoidiformes Number of families 1

Photo: A splendid coral toadfish (Sanopus splen-didus) near Cozumel, Mexico. Its striking appearance sets it apart from the other toadfishes. (Photo by J. W. Mowbray/Photo Researchers, Inc. Reproduced by permission.)

Photo: A splendid coral toadfish (Sanopus splen-didus) near Cozumel, Mexico. Its striking appearance sets it apart from the other toadfishes. (Photo by J. W. Mowbray/Photo Researchers, Inc. Reproduced by permission.)

Evolution and systematics

The family Batrachoididae is the only family in the order Batrachoidiformes, and is thought to be most closely related to the fishes in the order Lophiiformes containing the goose-fishes, frogfishes, and deepsea anglers. It has been divided into three subfamilies: Porichthyinae (Porichthys, 14 species and Aphos, 1 species) and Thalassophryninae (Daector, 5 species and Thalassophryne, 6 species) are the most derived and are restricted to the New World; Batrachoidinae containing at least 16 genera (including Opsanus and Sanopus) and about 51 species occur worldwide.

Physical characteristics

Toadfishes are small- to medium-sized fishes with a broad, flattened head and a wide mouth that usually has barbels and/or fleshy flaps around it. The eyes are on top of the head and directed upwards. The pelvic fins are forward, in front of the pectoral fins, and have one spine and three soft rays. There are two separate dorsal fins, the first with two or three spines, and the second is long with 15 to 25 soft rays. The anal fin is somewhat shorter than the second dorsal fin. The pectoral fins are large with a broad base. The gill openings are small and are restricted to the sides of the body. Species of Porichthys have photophores (light organs) along their sides and ventral surface. Species in the subfamily Thalassophryninae have hollow, venomous spines in their first dorsal fin and opercles. Bi-fax lacinia has a flap with an eye spot at the end of the maxilla on each side of the mouth.

Toadfishes usually are rather drab colored, often brownish with darker saddles, bars, or spots; however, some species in the Atlantic genus Sanopus are brightly colored. Maximum size of species ranges from 2.2 in (56 mm) to at least 20.1 in (510 mm) standard length.

Distribution

Worldwide between about 51° N and 45° S along continents in marine and brackish waters, occasionally entering rivers. Several freshwater species in South America.

In the New World Pacific Ocean: the genus Porichthys occurs from southeast Alaska south to Ecuador; Aphos from Peru south to Chile; Daector from Costa Rica to Peru; and Batrachoides from Mexico to Peru. In the New World Atlantic Ocean: Porichthys occurs from Virginia south to Argentina; Opsanus from Massachusetts south to Belize; Sanopus from Yucatan, Mexico to Panama; Triathalassothia in Belize, Honduras, and Argentina; Amphichthys from Panama to Brazil; Thalassophryne from Panama to Uruguay. Species of Daector,

An oyster toadfish (Opsanus tau) resting on the ocean floor. It makes a "grunting" sound when caught. (Photo by Tom McHugh/Photo Researchers, Inc. Reproduced by permission.)
The oyster toadfish (Opsanus tau) has been used in studies of insulin and diabetes, drug metabolism, hearing, dizziness and motion sickness. (Photo by David Hall/Photo Researchers, Inc. Reproduced by permission.)

Thalassophryne, and Potamobatrachus occur in freshwater in South America.

In the eastern Atlantic Ocean Batrachoides, Halobatrachus, Perulibatrachus, and Chatrabus occur along the African coast. South Africa has several genera: Chatrabus, Batrichthys, and Austrobatrachus. Barchatus is found in the Red Sea and adjacent areas, Bifax in the Gulf of Oman as well as Austrobatrachus, which ranges to India. Allenbatrachus ranges from India through the Indo-Australian archipelago to the Philippines and north to Thailand. Toadfishes have not been recorded from Taiwan or Japan. The genus Halophryne occurs on the west, north, and east costs of Australia, and north to the Philippine Islands, and Batrachomoeus has the same range in Australia and ranges north through the Indo-Australian archipelago to Vietnam.

Habitat

Toadfishes rest on and bury in the substrata and are found from the shoreline down to deep water, at least to 1,200 ft (366 m). They occur in full-strength sea water, brackish water, and also freshwater. Their usual cryptic coloration allows them to blend with the subtrata where they can function as ambush predators. The species in the genus Sanopus typically live in sand depressions under coral heads.

Behavior

Toadfishes are known for their sound production resulting from the contraction of muscles on the swim bladder. Both males and females produce agonistic grunts, whereas only males make longer courtship calls, "boat whistles," or "hums."

Feeding ecology and diet

In addition to being ambush predators, toadfishes also move about feeding on invertebrates, mostly crabs, shrimps, mollusks, sea urchins, and fishes, and others take planktonic organisms from the water column.

Reproductive biology

Males prepare nests, usually in a cavity under a rock or shell, including objects discarded by humans such as cans or bottles. Males attract females by vocalizations, and then females lay large, adhesive eggs and leave the area. Males guard and fan the eggs until after hatching. The young may remain in the nest after hatching, still attached to the nest surface and even after free swimming. The plainfin midshipman has two types of males, larger nest holding ones and smaller sneaker males that dart into nests attempting to fertilize eggs of a nesting pair.

Conservation status

The IUCN lists five species of toadfishes as Vulnerable— the Cotuero toadfish (Batrachoides manglae), the whitespotted toadfish (Sanopus astrifer), the whitelined toadfish (S. green-fieldorum), the reticulated toadfish (S. reticulatus), and the splendid coral toadfish (S. splendidus). A number of species appear to have very limited distributions.

Significance to humans

Larger toadfish species are eaten, although there is no specific fishery for them. Species in the genus Allenbatrachus are occasionally collected and sold in the aquarium trade as freshwater fishes. Species in the genera Opsanus and Porichthys are used in laboratory studies. Venomous toadfishes in the subfamily Thalassophryninae can inflict pain if handled.

1. Atlantic midshipman (Porichthys plectrodon); 2. Oyster toadfish (Opsanus tau); 3. Plainfin midshipman (Porichthys notatus); 4. Splendid coral toadfish (Sanopus splendidus). (Illustration by Jacqueline Mahannah)

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