Fin Erosion Research Articles

DISTRIBUTION OF NEOPLASMS AND OTHER DISEASES IN MARINE FISHES RELATIVE TO THE DISCHARGE OF WASTE WATER*

This study was based on an examination of approximately 290,000 fishes that comprised 151 species collected from southern California coastal waters, 1969 to 1976. Approximately 5 percent of the fishes were affected with external signs of disease, such as fin erosion, tumors, color anomalies, and attached macroparasites. Fin erosion diseases were reported in the greatest number of species and occurred at the highest frequencies. Fin erosion in Dover sole is the only disease that appears to be directly associated with discharge of municipal waste waters in southern California. It occurs primarily at one site, the Palos Verdes shelf, and appears to result from exposure to contaminated sediments at that site. The occurrence of skin tumors on young Dover sole covers an even wider geographic area, and the disease is quite similar to that which affects pleuronectids as far north as Bristol Bay, Alaska. The lack of association with specific waste discharge conditions coupled with an apparent relation to the life cycle of the Dover sole suggest that changes in waste discharge practices will have little impact on the prevalence of these tumors unless the changes affect survival rates and distributional patterns of young fish. The lack of infestation of Pacificmore » sanddabs by the parasite P. cincinnatus at Palos Verdes is curious and deserves further study. It is possible that the high levels of chlorinated hydrocarbons in the tissues of bottom fish at Palos Verdes are inimical to this and, possibly other, attached macroparasites.« less

ENVIRONMENTAL SIGNIFICANCE OF FIN EROSION IN SOUTHERN CALIFORNIA DEMERSAL FISHES*

The Dover sole was the species most often affected with eroded fins. Prevalence of the disease was highest on the Palos Verdes shelf, the site of a major municipal waste water discharge. Fin lesions in this species were characterized by a minimal inflammatory response and by the absence of associated microorganisms. The fins most frequently affected were those most often in contact with bottom sediments. Diseased specimens from the shelf had higher levels of total DDT and a tendency toward higher levels of total PCB in muscle tissue and a greater liver to body weight ratio than did unaffected specimens from the same area. Laboratory exposure of M. pacificus to contaminated sediments from the shelf resulted in the development of fin erosion. Chlorinated hydrocarbon levels and liver weight to body weight ratios in the exposed fish approached those measured in fish from the shelf. These studies suggest that fin erosion in M. pacificus is caused by exposure to contaminated sediments and that the role of chlorinated hydrocarbons should be tested directly in future experiments.

Hepatomas in marine fish from an urban estuary

Increased concern for the effects of urban wastes on aquatic animals prompted our investigation of the health of demersal fishes in the Duwamish River estuary, Seattle, Washington. The study of two diseases found in English sole (Parophrys vetulus) and starry flounder (Platichthys stellatus)--fin erosion (WELLINGS et al. 1976) and epidermal papillomas--led to the finding of hepatomas in English so~e. The frequency, gross pathology, and histopathology of the liver neoplasm will be reported here.

The occurrence of fin rot in mullet (Mugil cephalus) associated with crude oil contamination of an estuarine pond‐ecosystem

Four estuarine pond‐ecosystems equipped with tidal simulation were established and stocked with mullet, shrimp, and oysters. A 6 month pre‐spill sampling period established a consistently low incidence of disease in the mullet, Mugil cephalus, from all ponds. Following the preliminary study period, Empire Mix crude oil (4.0‐5.0 p.p.m.) was spilled on each of two of the ponds in mid‐July, 1974. Six to eight days following the oil spill all the mullet examined from the treated ponds had varying degrees of fin rot on one or more of their fins. The fin erosion involved primarily the caudal, pectoral, and pelvic fins with the caudal fin the most severely damaged. The degree of damage to the fins varied from a slight discoloration with no visible fraying to complete erosion of all of the fin elements. A gram negative rod tentatively identified as Vibrio sp. is considered the primary pathogen responsible for the fin erosion. Although the condition of the infected fish indicated the possibility of a systemic infection, only a low percentage of the kidney cultures taken from the diseased fish were positive indicating the infection was mostly external. The course of the infection was documented over a 56‐day period following the oil spill. Significantly, 96% of the mullet observed from the treated ponds had some degree of fin damage while only 6 % of those observed from the control ponds had eroded fins. The high incidence of fin rot which occurred in the estuarine‐pond ecosystems did not occur during numerous acute exposures of mullet to crude oil in the laboratory.

Fin Erosion Disease of Starry Flounder (Platichthys stellatus) and English Sole (Parophrys vetulus) in the Estuary of the Duwamish River, Seattle, Washington

Fin erosion in the starry flounder (Platichthys stellatus) and English sole (Parophrys vetulus) of the Duwamish River, Washington, is characterized by ulcerating chronic inflammation and fibrosis with resorption of fin rays. The end result is deformation, shortening, and retraction of residual fin tissue with loss of functional surface. We suggest that the incidence of fin erosion in a particular population is related to an interaction between genetic constitution and multiple environmental variables, including a variety of chemical pollutants.

Fin erosion in winter flounder

Abstract Diseased fish showing erosion of the fins have been recorded from polluted waters in several parts of the world. This article gives the results of a year's survey of fin erosion among fish in oceanic and estuarine waters of New York Bight. The pristine Great Bay was chosen as a control for the heavily contaminated Sandy Hook-Raritan Bay system. Almost all fin erosion was confined to demersal flat fish, particularly the winter flounder, a species which spends a long time in polluted estuaries near Sandy Hook.

Environmental Aspects of Fin Erosion and Tumors in Southern California Dover Sole

Abstract Between 1969 and 1972, a number of Dover sole (Microstomus pacificus Lockington) with eroded fins and skin tumors were collected in a series of trawls off the coast of southern California. Field and laboratory observations suggest that the two diseases were distinct syndromes operating at different growth stages in the life cycle of the Dover sole. Specimens with fin erosion were concentrated in the vicinity of the major municipal wastewater discharge site in the southern California area. Histological observations showed the disease to be external in nature: The distribution of the diseased fish and the patterns of erosion of the various fins suggest that the disease was brought on by contact with the sediments around the wastewater outfall. Tumor-bearing specimens were more evenly distributed throughout the southern California coastal waters, and the presence of the anomaly appeared to be a function of fish size (usually occurring in specimens of less than 150 mm standard length). The spatial an...

Essential Fatty Acids in the Diet of Rainbow Trout (Salmo gairdneri): Growth, Feed Conversion and Some Gross Deficiency Symptoms

Experiments are described to define further the fatty acid requirements of rainbow trout (Salmo gairdneri). In all cases, feeding semipurified diets containing no polyunsaturated fatty acids resulted in poor growth and feed conversion. Linolenic acid was superior to linoleic in stimulating growth and improving feed conversion. The requirement of linolenic acid (ω3 fatty acids) for rainbow trout is 1% of the diet or approximately 2.7% of the dietary calories. Essential fatty acid deficiency symptoms that were cured or prevented by linolenic acid included fin erosion, heart myopathy, and a shock syndrome. It is concluded that linolenic acid has an essential role in rainbow trout similar to that assigned to linoleic acid in man and higher animals.

The crystal resonator—a digital transducer: Hammond, P.L., Benjaminson, A., IEEE spectrum, vol 6, no 4 (April 1969) pp 53–58

Self-feeding systems, where fish actuate a trigger to obtain food, can be a useful feed management tool for aquaculture. However, some species such as the white-spotted charr Salvelinus leucomaenis can be poor self-feeders. The current experiment evaluated the production and welfare effects of growing a single competent self-feeding ‘demonstrator’ species, rainbow trout Oncorhynchus mykiss, in tandem with groups of inexperienced, ‘observer’ white-spotted charr. During Part I (PI, 50 days), all demonstrator groups (n = 4) utilised the self-feeders from day one, whilst no naïve charr successfully actuated the self-feeders. This enhanced utilisation had a significant and positive effect upon the growth and condition of observer charr. When demonstrator trout were removed during Part II (PII, 26 days), only one group of observer and one group of naïve charr started actuating the trigger, on the 1st and 21st day of PII, respectively. This resulted in poor growth performance in both observers and naïve charr, and there were no significant differences between treatments. However, observer fish still retained a significantly better condition factor than naïve fish at the end of PII. There were no significant differences in the levels of fin erosion, opercular erosion and mortality between observer and naïve charr throughout the experiment.This study confirms the previous assumption that white-spotted charr are poor self-feeders, but their production performance and welfare can be improved by growing charr in tandem with experienced and proficient self-feeding rainbow trout.

100MHz Surface acoustoelectric amplifier exhibiting stable terminal gain with dc drift field: Lakin, K.M., Collins, J.H., proc IEEE (April 1969) p 740

Self-feeding systems, where fish actuate a trigger to obtain food, can be a useful feed management tool for aquaculture. However, some species such as the white-spotted charr Salvelinus leucomaenis can be poor self-feeders. The current experiment evaluated the production and welfare effects of growing a single competent self-feeding ‘demonstrator’ species, rainbow trout Oncorhynchus mykiss, in tandem with groups of inexperienced, ‘observer’ white-spotted charr. During Part I (PI, 50 days), all demonstrator groups (n = 4) utilised the self-feeders from day one, whilst no naïve charr successfully actuated the self-feeders. This enhanced utilisation had a significant and positive effect upon the growth and condition of observer charr. When demonstrator trout were removed during Part II (PII, 26 days), only one group of observer and one group of naïve charr started actuating the trigger, on the 1st and 21st day of PII, respectively. This resulted in poor growth performance in both observers and naïve charr, and there were no significant differences between treatments. However, observer fish still retained a significantly better condition factor than naïve fish at the end of PII. There were no significant differences in the levels of fin erosion, opercular erosion and mortality between observer and naïve charr throughout the experiment.This study confirms the previous assumption that white-spotted charr are poor self-feeders, but their production performance and welfare can be improved by growing charr in tandem with experienced and proficient self-feeding rainbow trout.