PIKE FLY- FISHING ASSOCIATION

Member of the Salmon & Trout Association

                                      PIKE DISEASES

 

The pike is host to a

vast assemblage of parasites. Toner (1966) in his summary of information on the pike listed almost a full page of published records.  Hoffman (1967) listed the following parasites for this species in North America: fungi, Protozoa, Trematoda, Cestoda, Nematoda, Acanthocephala, leeches, Mollusca, and Crustacea. 

  

 The parasite most often seen and of concern to anglers is the strigeid fluke Uvulifer ambloplitis. The externally encysted stage of this trematode, called black-spot, is often present in extreme numbers on individual pike. This parasite is not transferable to man.

 

 

 This species also suffers from a septicaemic "red sore" disease caused by the bacterium Pseudomonas hydrophila, which is also responsible for the condition in frogs known as "red leg." In northern pike it results in ugly red necrotic lesions involving the muscle tissue (Margolis 1951). The pike also are subject to neoplastic tumors that are true cancerous lymphosarcoma. Both render the fish unsightly and can cause concern to those who catch the infected fish. Neither of these "diseases" is known to be transferable by contact to man. 

 

 

Broad Fish Tape Worm

 

Tapeworms are the most highly specialised flatworms. Adults parasitise the guts of vertebrates. The head or scolex bears attachment organs and is embedded in the wall of the gut. Tapeworms themselves have no guts. They absorb nutrients directly form the host’s gut through their tegument. The neck region protrudes into the lumen of the gut and buds off a chain (a strobila) of segments or proglottids, each with a set of male and female gonads. Mature proglottids usually release eggs, which pass out in the faeces and are then picked up by an intermediate host. The eggs hatch into a small hooked, hexacanth larva, which develops into a resting, often also proliferative stage, in the tissues of the host. The nature of this stage varies from species to species. The life cycle is completed when the flesh of the intermediate host is eaten by the definitive host in which the adult tapeworm develops The Broad fish tape worm in certain areas infects Pike and if the flesh is inadequately cooked and then eaten this parasite can be transferred to man.

 



    

9. NEOPLASMS OF NORTHERN PIKE (Esox lucius) AND MUSKELLUNGE (Esox masquinongy)

9.1 Neoplasms of the skin

Lymphosarcoma is a common disease involving the skin and dermis of northern pike. It occurs throughout North America and Europe and may reach prevalence rates of 10-20 percent (Sonstegard 1976). The disease in muskellunge has been observed from Lake Huron and the St. Lawrence River. The symptoms of the disease are similar in both the northern pike and muskellunge. Anatomically, the lesions can occur anywhere on the body. Grossly, the lesions vary in appearance depending upon their anatomic location. For example, skin lesions usually occur as reddish-purple "blisters" and ulceration is common (Figure 15), whereas fin lesions (the pelvic fin is commonly affected) appear as a greatly thickened irregular mass enveloping the fin. Jaw lesions produce reddening and thickening of the gingival tissue and lesions of the head may be a single nodule or appear as multiple coalescing groups. The occurrence of lymphosarcoma is cyclic and prevalence is highest in the spring and fall. It is almost always fatal to muskellunge (Sonstegard 1976)

Confounding lesions

Most lesions characterized by open sores (ulcers) can be confuse with lymphosarcoma. Similar symptoms may result from wounds, parasites (including lamprey), and bacterial, fungal, and viral infections. The need to confirm field diagnosis with histological diagnosis cannot be over emphasized.

Etiology

Extensive data indicate an infectious etiology. Lymphosarcoma is transmissible by inoculation of cell-free homogenates in northern pike, and in both species, cell-free homogenates yield evidence of the presence of an RNA virus (Papas et al. 1976). These diseases appear to have a viral etiology (Sonstegard 1976). Because of the pronounced seasonal variation in disease prevalence, samples collected at different seasons and/or water temperatures, will yield different prevalence data and confound temporal and spatial analysis.

Can anglers help prevent infections in fish?

YES!  Fish secrete a mucous coating over the entire length of their body that wards off fungal, viral and bacterial infections. If this muscous coating is removed, the fish becomes more suseptable to infection. Anglers can help prevent infections by taking extra care when returning fish to the water.To protect the mucous coating, remove the hook while the fish is still in the water or wet your hands before handling the fish. Release the fish gently and as quickly as possible after the hook is removed.