DISEASES OF MARINE FISHES
37
tumors were especially characteristic of pilotfish aiid developed within
a year after introduction of normal fish. Nigrelli (1952b) reported
malignant thyroid tumors in both wild and captive marine fish.
Tumors and hyperplastic growths in fishes may have a number of
causes other than genetic. Viral etiology for diseases such as lymphocystis has already been considered. Kudo (1924) and Nigrelli aiid
Smith ( 1 938, 1940) found Microsporidea and Myxosporidea associated
with tissue hyperplasia in certain fishes. Smith (1936) reported
papillomas of flounders possibly associated with invasion of larval
trematodes, and Reichenbach-Klinke (1955b) cited several instances
of fungi associated with tumors.
Increasing levels of pollution in the marine environment, in addition
to killing fish and destroying habitats, may produce abnormalities.
I n an interesting comparison of marine fishes taken in polluted and
unpolluted areas, Young (1964) described changes in consistency of
flesh, reduced weight, external lesions, exophthalmia and papillomas
as characteristic of fishes from grossly polluted waters off California.
External lesions on killifish, similar to those found on trawled species,
were produced experimentally by introducing sewer effluent diluted
with sea water. The possible association of pollution with increased
occurrence of n2oplnsnis in fishes had been made previously. Luck6
aiid Schlumberger (194 1) noted the common occurrence of epitheliomas
in catfish, Ictalurus nebulosus (LeSueur), from the Delaware River, and
Russell and Kotiii (1957) reported on papillomas of white croakers,
Genyonemus linentus (Ayres), from the same California area studied by
Abnormalities other than tumors have long attracted scientific
attention also. An unusual condition described as " jellied " flesh,
noted in several flatfish species, seems unrelated to a disease organism.
Templeman and Andrews (1956) reported the condition in 40% of the
catch of large American plaice, Hippoglossoides platessoides (Fabr.),
fished in cold waters of the Grand Bank of Newfoundland. Higher
water content and lower protein content made fillets perpared from
affected fish unsuitable for market. Most of the fish above 60 cm were
jellied. The authors postulated that large fish in cold waters could not
adequately meet protein demands of gonad development, tissue maintenance and growth. Evidence was cited for similar conditions in
other flatfish species as well as in cod and haddock that suggested a
generalized condition of muscle-protein impoverishment under stresses
of age, low temperature and gonad development.
Abnormalities in morphology are abundantly described in the
scientific literature. Gemmill (1912) published a book on teratology
Young.
37
tumors were especially characteristic of pilotfish aiid developed within
a year after introduction of normal fish. Nigrelli (1952b) reported
malignant thyroid tumors in both wild and captive marine fish.
Tumors and hyperplastic growths in fishes may have a number of
causes other than genetic. Viral etiology for diseases such as lymphocystis has already been considered. Kudo (1924) and Nigrelli aiid
Smith ( 1 938, 1940) found Microsporidea and Myxosporidea associated
with tissue hyperplasia in certain fishes. Smith (1936) reported
papillomas of flounders possibly associated with invasion of larval
trematodes, and Reichenbach-Klinke (1955b) cited several instances
of fungi associated with tumors.
Increasing levels of pollution in the marine environment, in addition
to killing fish and destroying habitats, may produce abnormalities.
I n an interesting comparison of marine fishes taken in polluted and
unpolluted areas, Young (1964) described changes in consistency of
flesh, reduced weight, external lesions, exophthalmia and papillomas
as characteristic of fishes from grossly polluted waters off California.
External lesions on killifish, similar to those found on trawled species,
were produced experimentally by introducing sewer effluent diluted
with sea water. The possible association of pollution with increased
occurrence of n2oplnsnis in fishes had been made previously. Luck6
aiid Schlumberger (194 1) noted the common occurrence of epitheliomas
in catfish, Ictalurus nebulosus (LeSueur), from the Delaware River, and
Russell and Kotiii (1957) reported on papillomas of white croakers,
Genyonemus linentus (Ayres), from the same California area studied by
Abnormalities other than tumors have long attracted scientific
attention also. An unusual condition described as " jellied " flesh,
noted in several flatfish species, seems unrelated to a disease organism.
Templeman and Andrews (1956) reported the condition in 40% of the
catch of large American plaice, Hippoglossoides platessoides (Fabr.),
fished in cold waters of the Grand Bank of Newfoundland. Higher
water content and lower protein content made fillets perpared from
affected fish unsuitable for market. Most of the fish above 60 cm were
jellied. The authors postulated that large fish in cold waters could not
adequately meet protein demands of gonad development, tissue maintenance and growth. Evidence was cited for similar conditions in
other flatfish species as well as in cod and haddock that suggested a
generalized condition of muscle-protein impoverishment under stresses
of age, low temperature and gonad development.
Abnormalities in morphology are abundantly described in the
scientific literature. Gemmill (1912) published a book on teratology
Young.