FASTING CONFINEMENT EFFECTS ON SHARKS 629 



In some elasmobranchs, alterations in interrenal morphology exist in ac- 

 cordance with the sexual cycle (Fancello 1937: Scy Ilium; Oguri 1960c: 

 Narke; Dittus 1941: Torpedo). No correlation between interrenal appearance 

 and reproductive status was observed for Triakis scy Ilia (Oguri 1960c); in the 

 present study the presence or absence of pups, or the relative ages of the 

 pups, did not correlate with the appearance of the interrenals. 



Observations reported above indicate lymphocytopenia, thrombocyto- 

 penia, and leukocytosis in the blood, with regression of lymphatic tissues 

 and an increase in tissue eosinophils and hypertrophy of phagocytic elements 

 of the reticuloendothelial system. Degenerative change in lymphatic tissue is 

 a common mammalian response to prolonged corticoid release (Cope 1972). 

 Alterations in the blood cell population of fishes following ACTH or Cortisol 

 injection include decreases in lymphocytes and thrombocytes (Weinreb 

 1968: Salmo gairdneri; Weatherley 1963: Perca fluviatilis) and increases in 

 neutrophils (Weinreb 1968: Salmo gairdneri). In Lepomis macrochirus, ad- 

 ministration of corticoids caused a hypertrophy of phagocytic cells of the 

 reticuloendothelial system and an increase in the presence of pigment gran- 

 ules (Fleming and Pasley 1965). 



In mammals, eosinopenia in the circulating blood follows corticoid ad- 

 ministration (Cope 1972) and is accompanied by an increased sequestration 

 of eosinophils in the spleen (Williams 1968). The present study reports an 

 increase in the eosinophils of both the blood and the tissues. With this 

 exception, the changes in histological appearance of the hematopoeitic tis- 

 sues resemble those attributed to the anti-inflammatory activity of corticoids 

 found in higher vertebrates. 



Ionic Alterations 



Little work has been done in examining directly the effects of starvation on 

 elasmobranchs. Hartman, Lewis, Brownell, Shelden, and Walther (1941) re- 

 ported elevated levels of serum sodium, chloride, and potassium in starved 

 Raja erinacea. Similar patterns were reported in later studies on the effects 

 of interrenalectomy on rajids, for both interrenalectomized and sham- 

 operated controls. In addition, this study reported an increase in serum 

 calcium. However, while Idler and Szeplaki (1968) reported increased serum 

 sodium and calcium, they observed decreases in serum potassium and chlo- 

 ride following interrenalectomy. 



In a later work, Idler (1969) described pools of corticosteriods in peri- 

 cardial and perivisceral fluids and suggested that the effects of inter- 

 renalectomy had been masked by a slow reentry of these cortical hormones 

 into the circulation. Thus it would appear that earlier studies had in fact 

 assessed only the effects of inanition. The present study agrees with Hartman 

 et al. (1941, 1944) with respect to increases in serum, sodium, potassium, 

 chloride, and calcium. 



In mammals, an increase in total body water accompanies sodium 

 retention during starvation or some other stress, and Baldridge (1972) 

 reported an increase in total body water in starved carcharhinid sharks. In 

 those elasmobranch species studied, integumentary permeability to water 



