Degenerative retinopathy in captive Atlantic menhaden, Brevoortia tyrannus (L.)

Abstract

Blindness developed in Atlantic menhaden, Brevoortia tyrannus (L.), within 4 weeks of captivity in an indoor open culture system. Ophthalmoscopic changes indicative of retinal degeneration were substantiated by the absence of retinal electrical activity as measured by conventional electroretinography. Results of histological evaluation suggest that photo-receptor degeneration, occurring initially in the rods of the central retina, was the primary abnormality. With chronicity. all retinal layers degenerated. and marked pigment proliferation developed. Other pathological changes included uveal vascular engorgement, vitreal and anterior chamber haemorrhage. and cataracts. With the exception of dermal hyperpigmentation, no systemic abnormalities were consistently observed. Phototoxicity is the suspected cause of this degenerative retinopathy.

Retinal and lenticular lesions in vitamin‐C‐deficient juvenile red drum, Sciaenops ocellatus (L.)

“…Factors that affect the threshold for light damage include the species, body temperature, light intensity and photoperiodicity (Bellhorn 1980;Tso 1989). Phototoxic retinopathy has been reported in several species of fish (Penn 1985;Raymond, Bassi & Powers 19SN;Nasisse et al 1989). In Atlantie menhaden, the eentra) retina was more severely affeeted than the peripheral retina (Nasisse et al 1989), as was the case in fish in this study.…”

“…The loealized involvement of the posterior subcapsular and cortical lens makes this particularly likely. Cataracts in this location are commonly associated with retinal degenerations in human beings and other species (Heckenlively 1982;Zigler & Hess 1985) and have been observed in fish with retinal degeneration (Nasisse, Noga & Davidson 1989). It has been suggested this type of cataract is caused by toxic aldehydes that are formed by lipid peroxidation of degenerating retinal tissue and that reach the lens via the vitreous (Zigler & Hess 1985).…”

Effects of Dissolved Carbon Dioxide on Cataract Formation and Progression in Juvenile Atlantic Cod, Gadus morhua L.

“…According to Menzies et al (), cataracts are potentially one of the most economically important diseases of farmed Atlantic salmon, Salmo salar . Product quality is often lowered because fish with cataracts often display dermal hyperpigmentation (Shariff et al ; Nasisse et al ). Also, as eye condition is an indicator of product quality, fish with cataracts may be unappealing in whole fish markets (Hargis ).…”